Subterranean coal seams contain substantial quantities of natural gas, primarily in the form of methane. Such reservoirs are commonly referred to as coal-bed methane (CBM) reservoirs. To effectively produce gas from CBM reservoirs, one or more stimulation methods are used to increase the output.
The most common CBM stimulation methods include directionally drilling parallel to the bedding of the seam, the creation of a cavity in a coal seam, or hydraulic fracturing of the coal.
Directional drilling involves angling the drill stem so that drilling is not vertical but will parallel the coal seam. Because the bore hole trends along the formation, a greater area of the wellbore is in contact with the coal seam and thus higher gas extraction is possible.
The cavitation completion method creates on or more cavities in the coal. The purpose is to reduce the amount of damage to the surrounding structure that may have resulted during drilling, to create an enhanced permeability zone outside of the cavitated area, and to reduce the near wellbore flow resistance arising from the convergence of flow in a radially inward flow field. Typically cavity completions are performed on open-hole completed wells (no casing across the production interval) in a cyclic manner thus the treatment is usually referred to as cavitation cycling as described for example in: Palmer, I. D., Mavor, M. J., Spitler, J. L., Seidle, J. P., and Volz, R. F. 1993b. Openhole cavity completions in coalbed methane wells in the San Juan Basin. Journal of Petroleum Technology, 45(11):1072-1080 (November).
Compressed air is most frequently used to pressurize the near wellbore zone. These gases can be foamed to reduce their apparent mobility in the cleat network and contain them in the near wellbore region where they will be most effective. The pressure is bled off as fast as possible, rubblizing the near wellbore zone and producing it out of the wellbore, creating a rather large cavity surrounding the wellbore. The procedure reduces the wellbore skin effect.
Cavitation cycling uses several mechanisms to link the wellbore to the coal fracture system. These mechanisms include creating a physical cavity in the coals of the open-hole section (up to 10 feet in diameter); propagating a self-propping, vertical, tensile fracture that extends up to 200 feet away from the wellbore (parallel to the direction of maximum stress and perpendicular to the minimum principal stress); and creating a zone of shear stress-failure that enhances permeability in a direction perpendicular to the direction of least stress as described for example in: Khodaverian, M. and McLennan. 1993. Cavity completions: a study of mechanisms and applicability. Proceedings of the 1993 International Coalbed Methane Symposium (Univ. of Alabama/Tuscaloosa), pp. 89-97.
Cavitation is accomplished by applying pressure to the well using compressed air or foam, and then abruptly releasing the pressure. The over-pressured coal zones provide a pressure surge into the wellbore (a “controlled blowout”), and the resulting stress causes dislodgement of coal chips and carries the chips up the well. These cycles of pressure and blowdown are repeated many times over a period of hours or days, and the repeated alternating stress-shear failure in the coal formation creates effects that extend laterally from the wellbore as described for example in: Kahil, A. and Masszi, D. 1984. Cavity stress-relief method to stimulate demethanation boreholes. SPE Paper No. 12843, Proceedings 1984 SPE Unconventional Gas Recovery Symposium (Pittsburg).
Fracturing is another important method to enhance CBM production. As described for example in: Holditch, S. A. 1990. Completion methods in coal seam reservoirs. SPE 20670, Proceedings 65th SPE Annual Technical Conference (New Orleans), p. 533., typically hydraulic fracturing is performed on cased-hole perforated completion wells typically when the coal permeability is less than 20 mD. There are a great many variations of hydraulic fracturing coal formations, but in a rough approximation, the techniques involve injecting a fluid into the formation at sufficient pressure to initiate and propagate a hydraulic fracture, filling the fracture with proppant by continuing injection of a proppant laden fluid, and then flushing the treatment so that the proppant fills the fracture but not the wellbore. Olsen, et al., describe some additional considerations for fracturing coal-bed methane reservoirs in: Olsen, T. N., Brenize, G., and Frenzel, T.: “Improvement Processes for Coalbed Natural Gas Completion and Stimulation,” SPE 84122, presented at the SPE Annual Technical Conference and Exhibition, Denver (Oct. 5-8, 2003).
Conventional hydraulic fracturing technique is described in many literature sources, as well as when applied to coal rocks. Directional drilling cannot be considered as a pure stimulation technique. It is worth to note that both fracturing (either conventional fracturing or cavitation) and directionally drilling simply increases the amount of the coal seam which is in direct contact with the well bore, and, no technological method has been found yet to increase the original porosity of the formation.    Palmer, I. D., Mavor, M. J., Spitler, J. L., Seidle, J. P., and Volz, R. F. 1993b. Openhole cavity completions in coalbed methane wells in the San Juan Basin. Journal of Petroleum Technology, 45(11):1072-1080 (November).    Holditch, S. A. 1990. Completion methods in coal seam reservoirs. SPE 20670, Proceedings 65th SPE Annual Technical Conference (New Orleans), p. 533.    Palmer, I. D., Lambert, S. W., and Spitler, J. L. 1993a Coalbed methane well completions and stimulations. Chapter 14 in AAPG Studies in Geology 38, pp. 303-341.    Olsen, T. N., Brenize, G., and Frenzel, T.: “Improvement Processes for Coalbed Natural Gas Completion and Stimulation,” SPE 84122, presented at the SPE Annual Technical Conference and Exhibition, Denver (Oct. 5-8, 2003).    Khodaverian, M. and McLennan. 1993. Cavity completions: a study of mechanisms and applicability. Proceedings of the 1993 International Coalbed Methane Symposium (Univ. of Alabama/Tuscaloosa), pp. 89-97 or the above paper by Kahil, A. and Masszi, D. 1984.
Fracturing fluid leak-off through the cleat network during the fracturing process is a major limitation of modern hydraulic fracturing methods in CBM reservoirs. Fracturing fluid efficiency is the simple ratio of the volume of the created fracture at the end of pumping divided by the total volume of fluid injected to create the fracture. For obvious reasons, low fracturing fluid efficiency is undesirable. Expense and waste aside, the leaked off fluid can substantially reduce the permeability of the cleat network and defeat the benefit of the stimulation treatment. Moreover, due to various operational constraints (such as maximum injection pressure, maximum injection rate, cost, etc.) low fluid efficiency limits the fracture length that may be achieved.
Fracturing fluids injected into CBM reservoirs create a complex fracture comprised of some dominant channel and numerous minor channels. The minor channels may be part of the cleat network. High leak-off of the fracturing fluid through the cleat network reduces both the rate of growth of the main fracture and the maximum fracture length. Injecting the fracturing slurry at higher flow rates can compensate for leak-off losses, but the leaked off fluid may be trapped in the cleats, blocking the pathway through which reservoir fluids can flow from the reservoir to the wellbore. The cleat aperture can be too small for proppant to enter and prop the cleats in normal practice. Recently, fracturing fluids have been developed that are non-damaging to cleats. Whilst leaking off into the cleat network, they are free of macro-molecules that create immobile plugs in the cleats. Thus, because they are free of polymers and insoluble solids, the non-damaging filtrate is easily displaced from the cleats when the well is put on production. Olsen et al above describe such a fracturing fluid.
It is also known to use water-based fluids with dewatering aids and proppant. The presence of water in a porous medium reduces the flow capacity of that medium to other immiscible fluids such as oil or gas. In the case of CBM reservoirs, water from the injected hydraulic fracturing fluids can infiltrate the cleat network and negatively impact the surface properties (mainly wettability) of the coal. These changes can result in reduced dewatering and lead to coal fines migration, which can plug the cleats. U.S. Pat. No. 5,229,017, by Nimerick and Hinkel, describes chemicals, such as butoxylated glycols, that adsorb onto coal surfaces, rendering them hydrophobic. The hydrophobic coal surface maintains the original surface properties of the coal and hinders re-wetting and re-absorption of surfactant present in the fracturing fluid. These surfactants are delivered in the fracturing fluid and result in more rapid coal dewatering and fracturing fluid recovery out of the fracture.
Other known techniques attempt to control the leak-off into cleats. For example, U.S. Pat. No. 5,474,129 describes a process of using injected gases to perform cavity completions. Water with a foaming agent is added to the gas to create a foam downhole. The foam reduces the rate of gas leaking away from the wellbore through the cleat network. Instead, gas is trapped in the near wellbore region where it adsorbs into the near wellbore coal. Upon depressurization, the trapped gas expands and destroys the coal fabric and promotes the cavity completion process. This patent is referenced because it identifies the role of the cleats in conducting fluids away from a source. Foamed fracturing fluids are often used in CBM reservoirs to control leak-off, to reduce the hydrostatic head in the wellbore at the end of the treatment (and improve fracturing fluid recovery), and to reduce the amount of damaging polymers that enter the cleat network.
Methods of enhancing coal-bed methane production are considered enhanced recovery techniques. Enhanced recovery techniques involve flooding the CBM reservoir with gases that adsorb to coal more strongly than methane, and thus displace methane or lighter hydrocarbones from the micropore structure of the coal. Several papers describe various aspects of this technique including:    Fulton, P. F., Parente, C. A., Rogers, B. A.: “A Laboratory Investigation of Enhanced Recovery of Methane from Coal by Carbon Dioxide Injection,” SPE/DOE 8930, presented at the 1980 SPE/DOE Symposium on Unconventional Gas Reservoirs, Pittsburg (May 18-21, 1980);    Chaback, J. J., Morgan, D., and Yee, D.: “Sorption Irreversibilities and Mixture Compositional Behavior During Enhanced Coal Bed Methane Recovery Processes,” SPE 35622, presented at the Gas Technology Conference, Calgary (Apr. 28-May 1, 1996);    Zhu, J., Jessen, K., Kovscek, A. R., and Orr, F. M.: “Analytical Theory of Coalbed Methane Recovery by Gas Injection,” SPE Journal, pp 371-379 (December 2003); or    Gorucu, F. B., Jikich, S. A., Bromhal, G. S., Sams, W. N., Ertekin, T., and Smith, D. H.: “Matrix Shrinkage and Swelling Effects on Economics of Enhanced Coalbed Methane Production and CO2 Sequestration in Coal,” SPE 97963, presented at the 2005 SPE Eastern Regional Meeting, Morgantown (Sep. 14-16, 2005).
The use of liquid gas fracturing with proppant with mixtures of carbon dioxide and nitrogen or only carbon dioxide is published in general and is used for example in Canada and in the Eastern United States for shallow gas well stimulation. Liquid CO2 or foams/emulsions created by mixtures of CO2 and nitrogen are reported to be undamaging because the fluid will vaporize and be produced after the treatment. Descriptions of the known methods can be found for example in:    Lillies, A. T., and King, S. R.: “Sand Fracturing with Liquid Carbon Dioxide,” SPE 11341, presented at the SPE Production Technology Symposium, Hobbs (Nov. 8-9, 1982);    Yost, A. B., Mazza, R. L., and Gehr, J. B.: “CO2/Sand Fracturing in Devonian Shales,” SPE 26925, presented at the SPE Eastern Regional Meeting, Pittsburg (Nov. 2-4, 1993);    Mazza, R. L.: “Liquid-Free CO2/Sand Stimulations: An Overlooked Technology—Production Update,” SPE 72383, presented at the SPE Eastern Regional Meeting, Canton (Oct. 17-19, 2001); and    Cambell, S. M., Fairchild, N. R., and Arnold, D. L.: “Liquid CO2 and Sand Stimulations in the Lewis Shale, San Juan Basin, New Mexico: A Case Study,” SPE 60317, presented at the SPE Rocky Mountain Regional/Low-Permeability Reservoirs Symposium and Exhibition, Denver (Mar. 12-15, 2000).
Once the appropriate bore hole(s) is completed by using one of the above methods, dewatering must occur to reduce the pressure in the formation. Pressure drop in turn promotes methane release from within the coal into the cleats. If the cleats contain a high enough permeability, that is, inter-connectivity, then the methane will flow from the coal into the well bore and can be extracted.
In U.S. Pat. No. 6,412,559, there is described a process of stimulating and enhancing methane production in coal reservoirs. The process uses a stronger adsorbing gas (SAG, stronger than methane such as carbon dioxide or H2S), which swells the formation during the fracturing process, the key element of their process is repeated SAG injection and shut-in steps after the stimulation treatment. The shut-in steps may be between 1 day and 1 year in length. The principle reason for the use of a SAG is to promote enhanced coal-bed methane recovery as the SAG preferentially adsorbs onto the coal and displaces adsorbed methane. The fracturing is employed at the beginning of the repeated SAG injection and shut-in steps to improve the infectivity of the SAG, i.e., the fracturing step is to reduce wellbore skin and enable improved CO2 injection.
In the published US patent application 20050082058 the reaction of a predetermined gas with the coal is used to induce shrinkage within the coal matrix, thus reducing effective stress and enhancing the fracture void volume. This increased fracture void volume increases coal-bed permeability and resultant increase in methane gas flows. It also allows placement of proppant within the coals to maintain open fractures in the regions surrounding the propped fracture, thus allowing the enhanced fracture system to communicate more effectively with both the natural fracture system and the wellbore and aiding methane recovery.
In the U.S. Pat. No. 5,014,788 there is described a method to improve production by introduction of a swelling gas into the coal which after release generates uneven stress fractures. The emphasis of the known method is in the “relatively rapid reduction” in the pressure.


1. Field of the Invention
The present invention relates generally to a system and method for easy and rapid instruction of second language skills. More particularly, the present invention relates to a system and method for rapid instruction of second language skills that can accelerate profession-specific language learning skills.
2. Related Art
While it may be that the English language is the primary, or most used, language in the United States, the number of people in the U.S. who do not speak English is increasing daily. For instance, it has been estimated that the number of U.S. residents who speak Spanish may shortly outnumber the residents who speak English. This increase of non-English speaking residents posses difficulties for many businesses and organizations. For example, many businesses located in the U.S. are structured around the English language. Advertisements, menus, directions, etc. are often provided in English. Many of a business' employees may speak little or no foreign (that is, non-English) languages. Conversely, an increasing number of an employer's employees may have little or no skill in speaking English.
In order to provide effective service to people who do not speak English, a business currently has a limited number of options. First, it may recruit and hire employees who speak multiple languages and who are capable of communicating and serving speakers of languages other than English. This is problematic in that the number of available people in the job pool are correspondingly decreased and the cost of employing the employees is increased.
Second, a business may train its existing employees in other languages to enable them to better serve customers who speak languages other than English. This option is problematic in that current foreign language systems can be very costly and very time consuming, and aren't focused toward teaching the basic language skills needed to communicate on a basic level with a speaker of the second language. Also, most conventional training systems are focused primarily on teaching second language skills which encompass a large array of situations in which a person may require or use the second language, rather than focusing on specific needs for a particular profession.
These problems also arise in the instance where a business employs employees who speak little or no English, but who are nonetheless expected to serve English speaking customers.


Nowadays, in order to improve spectral efficiency, modern wireless communication systems use modern modulation and coding scheme techniques that involve multiple subcarriers direct or indirect mapping, such as OFDM (orthogonal frequency division multiplexing), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single-carrier frequency division multiple access), WCDMA (wideband code division multiple access) or multi-carrier GSM (global system for mobile communication). These systems however suffer from high peak to average power ratios (PAPR), which originate from superposing subcarriers or various signals from diverse users. It is known that such kind of high PAPR is undesired because it requires more back-off for the subsequent power amplifier, and thus has a direct consequence on the amplifier's average output power. In order to reduce the dynamics of the incoming composite antenna signal, techniques like Crest Factor Reduction (CFR) are used to improve the PAPR and improve the efficiency of the transmission chain. However such processing algorithms may cause out-of-band spectral regrowth if not designed correctly, leading to non-compliance to regulatory spectral emission masks (SEM).
The noise shaping process is a clipping and filtering crest factor reduction technique which has been proposed to reduce the PAPR. The objective of the noise shaping process is to remove energy from the peaks of a signal and then to add that energy as a noise, inside and outside the signal bandwidth. As a result, the foregoing has the effect of reducing the PAPR as well as introducing in-band distortions which increase the bit-error ratio and also out-of-band degradations which interfere with communications in neighboring frequency bands.
Although effective, it would be desirable to improve the noise shaping process to reduce the PAPR even more.


This invention relates to sensors that measure torque applied to a shaft. It particularly relates to sensors having a sleeve torsionally engaged with the shaft and sensing means responsive to torsional strain in the sleeve.
Many known torque sensors operate by responding to magnetostrictive effects resulting from strain in a stressed member or transducer. Some of these are in commercial production. Efforts have been directed toward using magnetostrictive effects to measure the torque applied to the steering wheel by the driver of a motor vehicle. One known design torsionally engages a sleeve having desirable magnetostrictive properties to a portion of the steering wheel shaft. Another design uses the magnetostrictive properties of a current production steering wheel shaft to eliminate the cost of attaching a sleeve to the steering wheel shaft. In a third known design magnetostrictive material is beam or vapor deposited on a steering wheel shaft. The known designs have not proved entirely satisfactory. Known methods of attaching a sleeve require processes that are not easily adapted to large volume production. The same is true of beam or vapor deposition of magnetostrictive materials. Efforts to use the shaft itself have suffered from the difficulty of obtaining shafts consistently having desired magnetostrictive properties. For measuring steering torque in an automobile the ideal sensor would be inexpensive and compatible with existing steering wheel shafts.
The expression xe2x80x9ctorsionally engagedxe2x80x9d is used herein to describe engagement between a first element and a second element for transmitting torque therebetween. It includes engagement for transmitting torque by a rigid attachment such as a weld or adhesive joint or both elements being made of one piece of material. It also includes engagement by means that transmit only torque exemplified by a wrench socket engaging the head of a bolt. The expression xe2x80x9ctorsionally engagedxe2x80x9d is used to cover a broad range of torque transmitting engagement means that may or may not transmit forces in addition to torque.
A torque sensor incorporating a sleeve of magnetostrictive material is described in U.S. Pat. No. 5,351,555 issued Oct. 4, 1994 to Garshelis. Particular attention is focused on the Garshelis patent because it is believed to offer the lowest cost sensor responsive to torque applied to a magnetostrictive sleeve. However, the invention is applicable to any torque sensor having a sleevelike transducer that is torsionally stressed when torque is applied to a shaft.
The Garshelis design provides a sleeve (xe2x80x9ctransducerxe2x80x9d) permanently magnetized in its circumferential direction. Garshelis discusses attachment of the transducer to the torsionally stressed shaft and (column 15 beginning at line 7) describes requirements which must be met by the chosen method of attachment:
xe2x80x9cproper operation . . . requires that there be no slippage between any of the components at their interfaces. . . . Somewhat less obvious, but no less important, is the requirement that there be no inelastic strain in shaft 8 in any cross section which includes the transducer 4. Thus, all strains associated with the transmission of torque must be fully recoverable when the torque is relaxed.xe2x80x9d
and in column 16 beginning at line 5
xe2x80x9cAs already indicated, the transducer 4 and underlying shaft must act as a mechanical unit. Rigid attachment of the transducer 4 either directly or indirectly to shaft 8 is crucial to proper operationxe2x80x9d.
In fact, attachment by adhesive bonding (using known adhesives and known designs) or interference fit (Garshelis"" preferred method) do not satisfy the above quoted requirements. All known designs based on adhesive bonding or interference result in peak stresses exceeding the capabilities of the bond.
In column 16 beginning at line 5 and continuing through line 23 of column 17 Garshelis discusses three categories of torsional engagements between the transducer and the shaft. The categories are 1) salient point, i.e. splines, knurls, teeth etc. at the ends of the transducer mating with similar features on the shaft; 2) distributed, i.e. adhesive bonding or interference fit; 3) diffuse, i.e. welding or brazing the ends of the transducer to the shaft. The first xe2x80x9c1) salient pointxe2x80x9d and the last xe2x80x9c3) diffusexe2x80x9d work well but manufacturing methods for achieving these attachments are not easily adapted to automotive manufacturing procedures.
About friction or adhesive bonding Garshelis states (column 16 lines 37 through 41):
xe2x80x9cThis bonding limits the maximum measurable torque to a lower value than might otherwise be handled by the shaft 8 alone or transducer 4 alone, but is advantageous for other reasons as indicated previously.xe2x80x9d
Accordingly, Garshelis expresses a known need for an xe2x80x9cadvantageousxe2x80x9d process such as adhesive bonding that does not limit the maximum measurable torque to xe2x80x9ca lower value than might otherwise be handled by the shaft 8 alone or transducer 4 alonexe2x80x9d. Garshelis goes on to state (column 16 lines 41 through 47):
xe2x80x9cPress or shrink fits can be used to obtain the desired circular anisotropy, and can provide very substantial gripping forces which as a practical matter will not be broken by expected torques on shaft 8. With clean, degassed (and perhaps deoxidized) surfaces, the effective coefficient of friction can rise without limit and act somewhat like a weld.xe2x80x9d
Providing xe2x80x9cclean, degassed (and perhaps deoxidized) surfacesxe2x80x9d on the elements before they are joined by press or shrink fits is expensive and time consuming. It is difficult to assure such qualities in many millions of parts as required for automotive production. It is not stated in the Garshelis patent but it is believed that to achieve in a press fit an effective coefficient of friction that xe2x80x9ccan rise without limit and act somewhat like a weldxe2x80x9d as stated in Garshelis the xe2x80x9cclean, degassed (and perhaps deoxidized) surfacesxe2x80x9d must be joined and heat treated at high temperatures in a suitable atmosphere for many hours. To obtain a shrink fit heat treatment is believed to be required both to achieve an effective coefficient of friction that xe2x80x9ccan rise without limit and act somewhat like a weldxe2x80x9d and to cause the shrinkage required for a shrink fit.
Another method of achieving an interference fit between the transducer and the shaft is described by Garshelis with reference to FIGS. 14, 15 and 16. In this method the shaft is hollow and an expander is drawn through the shaft to expand it thereby providing the desired hoop stress. This process also is believed to be difficult and expensive to implement in mass production of steering wheel shafts.
The following numerical examples will clarify the issues related to attaching a sleeve by adhesive or interference fit (without heat treatment or other processes to achieve an effective coefficient of friction that xe2x80x9ccan rise without limit and act somewhat like a weldxe2x80x9d). In column 10 lines 3 through 5 Garshelis cites the example of a shaft diameter of 0.5 inch (1.27 centimeters) and a transducer wall thickness in the 0.030 to 0.050 inch (0.076 centimeters to 0.127 centimeters) range. The wall thickness is important to achieve sufficient magnetic flux (Garshelis column 10 lines 24 through 31). From the well known fact that torque transmitted by a shaft is distributed as the third power of the radius it follows for the case of the aforementioned 0.5 inch diameter shaft that if the transducer and shaft have similar shear moduli (which is likely to be the case) 36 percent of the total torque will be transferred to the transducer in the case of 0.030 inch transducer wall thickness and 52 percent of the total torque will be transferred to the transducer in the case of 0.050 inch transducer wall thickness. A possible diameter of a steering wheel shaft of an automobile is 2 cm and it might be subjected to a maximum torque of 600 newton-meters (450 ft-lbs). Such a torque might be applied by a large healthy male driver after the wheel reached the end of its travel. At the one centimeter radius of the outer surface of the steering wheel shaft 600 newton-meters torque creates a tangential force of 60,000 newtons (13500 lbf). If 36 percent of the torque is transmitted to the transducer 21,600 newtons (4860 lbf) must be transferred between the transducer and the shaft by the attachment means. The fraction of the force transferred between the transducer and the shaft would be 36 percent in the case of the 2 centimeter diameter shaft if the inside diameter of the transducer is also 2 centimeters and the thickness of its wall is 1.2 millimeters (0.047 inches). The fraction would be much larger if the inside diameter of the transducer is larger and the thickness remains 1.2 millimeters. Assuming an adhesive shear strength of 10 newtons per square millimeter (1419 psi) and assuming means exist for providing constant shear stress over the area of adhesive attachment, transferring 21,600 newtons requires 21.6 square centimeters or 3.5 centimeters of shaft length of bonded area at each end of the transducer.
The second example is an interference fit. If the transducer wall thickness is 1.2 millimeters and is stressed to a hoop stress of 700 mpa (100,000 lbf/in2) and the coefficient of friction is 0.3, 1575 newtons (353 lbf) of shear force can be transferred per millimeter of length. Transferring the aforementioned 21,600 newtons of shear force requires about 1.4 centimeters of shaft length of contact with the shaft at each end of the transducer.
In summary, in the case of a two centimeter diameter steering wheel shaft, both bonding by adhesive and attachment by press fit would require contact with the shaft for one to four axial centimeters beyond each end of the active area of the transducer to transmit the forces encountered in operation assuming uniform shear forces. To prevent higher stresses that would cause adherence to fail the shear force must be distributed uniformly over the area of attachment. In fact, known technology does not enable the hereinabove reproduced requirements (Garshefis column 16 lines 37 through 41 and column 16 lines 41 through 47) to be achieved with any amount of adhesive or conventional press fit adherence area because the shear stresses peak at the ends of the attachment regions and exceed the maximum shear capabilities of adhesives and/or press fits.
A substantial difference is now evident between xe2x80x9cdistributed attachmentxe2x80x9d (adhesive, friction) and xe2x80x9csalient point attachmentxe2x80x9d and xe2x80x9cdiffuse attachmentxe2x80x9d. In the latter two attachment is truly at the ends of the transducer and the transducer operates as a unit with the shaft. This is also true in the aforementioned case where the effective coefficient of friction rises without limit and acts somewhat like a weld which is believed to be properly categorized as a xe2x80x9cdiffuse attachmentxe2x80x9d. In the xe2x80x9cdistributed attachmentxe2x80x9d cases attachment forces are required to be distributed over lengths of shaft such as the aforementioned one to four centimeter attachment regions at each end of the transducer.
It will also be appreciated from the above numerical examples taken with the following that where the transducer has a constant thickness as illustrated in FIGS. 1, 3, 4 and 6 through 16 of Garshelis (all of the figures that illustrate transducers) the end portions of the transducer do not xe2x80x9cact as a mechanical unitxe2x80x9d with the steering wheel shaft unless the ends are effectively welded to the shaft. For the transducer to xe2x80x9cact as a mechanical unitxe2x80x9d with the steering wheel shaft it must twist as the steering wheel shaft twists over its entire length. However, if a constant thickness transducer is attached by adhesive or press fit, sufficient torque to twist the transducer and cause it to xe2x80x9cact as a mechanical unitxe2x80x9d with the steering wheel shaft is only achievable in a xe2x80x9ccentral regionxe2x80x9d between the aforementioned attachment regions. Outside the xe2x80x9ccentral regionxe2x80x9d the torque available to twist the transducer diminishes with distance from the xe2x80x9ccentral regionxe2x80x9d because the transmission of torque is xe2x80x9cdistributedxe2x80x9d and the twisting of the transducer diminishes as the torque diminishes with distance from the central regions causing the torsional strain of the transducer and the shaft to be different far from the central regions. In Garshelis"" words cited hereinabove: xe2x80x9cThis bonding limits the maximum measurable torque to a lower value than might otherwise be handled by the shaft 8 alone or transducer 4 alone.xe2x80x9d
An object of this invention is to provide a torque sensor transducer which can be attached by adhesive to a torque carrying shaft and which will then operate xe2x80x9cas onexe2x80x9d with the torque carrying shaft.
A general object of this invention is to provide a torque sensor which also overcomes certain disadvantages of the prior art.
The present invention provides a torque sensor for measuring the torque applied to a shaft. It comprises a magnetostrictive sleeve torsionally engaged with two shear levelers. The shear levelers are bonded by adhesive to the shaft. The shear levelers have flared ends and regions of varying torsional elasticity that operate to level the shear stress in the adhesive. The term xe2x80x9clevelxe2x80x9d is used herein with reference to shear stress in adhesives to describe causing the shear stress to be constant and without peaks over the area bonded by adhesive. It may include being constant at two or more different levels at two or more areas bonded by adhesive.
Further, in accordance with the invention, the torque sensor is attached to the shaft by adhesive which is stressed in shear without stress peaks thereby enabling designs wherein the adhesive can transfer torques approaching the yield limit of the shaft.
Further, in accordance with the invention, the shear levelers have varying torsional stiffnesses to provide a uniform shear stress in the adhesive.
Further, in accordance with the invention, the shear levelers have flared ends and varying thickness adhesive at the flared ends further distributes stress in the adhesive and enables designs wherein the adhesive transmits torques that approach the yield torque of the shaft.
Further, in accordance with a first embodiment of the invention, low magnetic permeability isolation rings magnetically isolate the shear levelers from the magnetostrictive central segment.
Further, in accordance with the aforementioned first embodiment of the invention, the isolation rings are welded to the shear levelers and the magnetostrictive central segment.
Further, in accordance with the aforementioned first embodiment of the invention, the magnetostrictive central segment is pressed onto a stack of washers with crowned outer circumferences that maintains the transducer in its cylindrical shape and minimizes the torque that must be accumulated by the shear levelers. Great hoop stress in the magnetostrictive central segment is achieved by heat treatment after the magnetostrictive central segment is pressed onto the stack of washers.
Further, in accordance with the aforementioned first embodiment of the invention, each washer of the aforementioned stack of washers with crowned outer circumferences is coated with a thin layer of material that evaporates during heat treatment thereby leaving each washer separated from adjacent washers and therefore free to rotate without friction when the transducer is torsionally strained.
Further, in accordance with a second embodiment of the invention, the shear levelers are unitary with a low magnetic permeability middle segment upon which the magnetostrictive central segment is pressed and welded and possibly shrunk whereby great hoop stress in the magnetostrictive central segment is achieved which advantageously provides desirable magnetic properties.
Further, in accordance with the aforementioned second embodiment of the invention, the shear levelers are unitary with a low magnetic permeability middle segment upon which the magnetostrictive central segment is placed and welded and great hoop stress in the magnetostrictive central segment is achieved by expanding the middle segment and the magnetostrictive central segment together which advantageously provides desirable magnetic properties.
Further, in accordance with a third embodiment of the invention, the shear levelers are unitary with the magnetostrictive central segment and annular grooves are provided between the shear levelers and the magnetostrictive central segment. The grooves enhance magnetic anisotropy and provide surfaces against which force may be applied to facilitate installation of the transducer on the shaft.
Further, in accordance with the invention, a torque sensor comprises a circularly symmetric magnetic element centered on the rotation axis of a magnetostrictive element for providing a lower reluctance magnetic field path and less sensitivity to a bent shaft or other asymmetry.
A complete understanding of this invention may be obtained from the description that follows taken with the accompanying drawings.


Existing communications methods and systems are overly power hungry and/or spectrally inefficient. Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such approaches with some aspects of the present method and system set forth in the remainder of this disclosure with reference to the drawings.


Currently, the Wi-Fi Alliance is proposing that packets be aggregated into larger groups of packets before being sent in tunnel mode to a remote station (STA). For stations that support a VHT (Very High Throughput) mode, the number of aggregated packets may be very large. The aggregation is a key part of reaching a stated goal of 1 gigabit per second for wireless communications.
The selection of the number of packets to be aggregated greatly affects the transmission rate, the amount of overhead, and the airtime required to transmit the packet. In addition, to aggregate packets, the system must wait for all of the packets that are to be aggregated to arrive before they can be aggregated. In addition, the system must wait for enough packets to arrive to satisfy the conditions for aggregation. This introduces delays that impact applications or user experiences.


Certain oxadiazine compounds have been described as useful as pesticides and as pharmaceutical agents. For example, U.S. Pat. No. 5,536,720 describes substituted 2-phenyl-1,3,4-oxadiazine-4-carbamide compounds useful as insecticides and acaricides. Trepanier et al, J. Med. Chem 9: 753-758 (1966) describe certain 2-substituted 4H-1,3,4-oxadiazines useful as anticonvulsants in mice. U.S. Pat. No. 3,420,826 describes certain 2,4,6-substituted 4H-1,3,4-oxadiazines, useful as sedatives, anticonvulsants, and as pesticides against nematodes, plants, and fungi. U.S. Pat. No. 3,420,825 describes methods for producing certain 2,4,6-substituted 4H-1,3,4-oxadiazines.
It is a purpose of this invention to provide novel dihydrooxadiazine derivatives useful as insecticides.


This section is intended to provide information relevant to understanding various technologies described herein. As the section's title implies, this is a discussion of related art that should in no way imply that it is prior art. Generally, related art may or may not be considered prior art. It should therefore be understood that any statement in this section should be read in this light, and not as any admission of prior art.
In modern manufacturing of integrated circuits, conventional cell architecture designs are typically generated with two-dimensional Electronic Design Automation (EDA) tools that are inefficient and cumbersome to employ. Some 2D design flows may directly adopt a 2D placement solution to determine the standard cell and inter-tier via locations, with limited results for three-dimensional (3D) optimizations. Some other 2D design flows propose block partitioning for 3D optimizations across multiple tiers. However, the inter-tier via locations are typically determined by the 2D placement solution from a single tier, which lacks co-optimization between multiple tiers.


1. Field of the Invention
The present invention relates to an image forming apparatus which displays a preview upon outputting images of a plurality of pages, a control method thereof, and a storage medium.
2. Description of the Related Art
Some image forming apparatuses such as digital multifunction peripherals (MFPs) include a function of displaying a thumbnail of a generated page image as an image formation target on a liquid crystal panel of an operation unit as a preview so as to prevent a wasteful output due to a setting error. In an image forming apparatus which includes post-processing functions such as stapling, folding, and punch hole functions, a method of processing a page image generated based on input print data, and displaying a finish preview which allows the user to recognize a final output form applied with post-processes has been proposed.
For example, Japanese Patent Laid-Open No. 2003-87560 has proposed an image forming apparatus which displays pages in a two-page spread state except for the first and last pages, when post-processing is stapling processing upon displaying a finish image indicating a state applied with the post-processing by processing image data obtained by converting input image data to reduced-scale data. Also, Japanese Patent Laid-Open No. 2010-35030 has proposed a preview method which prevents user's confusion by displaying finish information outside a print sheet area of a preview image so as to improve visibility, and deciding a direction of the preview image in accordance with the convey direction of a sheet.
However, the above related arts suffer the following problems. For example, in an image forming apparatus which includes a preview function in consideration of post-processing like in the related art, the user can confirm if post-processing settings are as the user intended, but a configuration which allows the user to recognize a relationship between pages before and after a preview target page is not provided. That is, in a preview of the related art, a preview image is displayed by reflecting a finish result for each page image of a sheet, or only the method of displaying sheets in a two-page spread state upon designation of stapling as a case in which pages are displayed to allow easy understanding of an anteroposterior relationship has been proposed. For this reason, in an image forming apparatus including various finishing functions and output instruction forms, a preview method which allows the user to easily recognize a relevance according to output forms between a plurality of pages such as the anteroposterior relationship or positional relationship of a plurality of pages to be output is demanded.


This invention relates to a method for the cleavage of carboranyl carbon-silicon bonds in compounds and polymers containing same, and in addition, to a method for preparing meta-carborane using this technique.
ORTHO-Carborane, of the empirical formula C.sub.2 B.sub.10 H.sub.12, has an icosahedral structure and was the first icosahedral carborane discovered and prepared in quantity. Subsequently, methods were developed for isomerizing the ortho derivative to the meta-and para-isomers. For example, ortho-carborane may be rearranged or isomerized to meta-carborane in a hot tube flow process at high temperatures (i.e., 600.degree. C) involving short residence times. See S. Papetti, et al, Industrial Engineering Chemical Product Research and Development, 5,334 (1966). At these temperatures, carborane vapors may burn or explode if allowed to contact air and hence such a process is not attractive for industrial operation.
Another process is known for isomerizing carboranes in bulk and is disclosed in U.S. Pat. No. 3,440,265. The process involves the thermal rearrangement of large silyl group-substituted ortho-carboranes to the metal-isomer at significantly lower temperatures than the prior technique. In contrast to the earlier flow process, this bulk isomerization occurs readily at the reflux temperature and can be performed using conventional laboratory equipment. Furthermore, the method is adaptable to large-scale industrial production.
The metal-isomer has become increasingly important as the key ingredient of high performance metal-carborane-siloxane polymers. Such polymers have excellent high temperature characteristics and can be prepared by methods known in the art. For example, linear, high molecular weight carborane-siloxane polymers and methods for their preparation are disclosed in commonly-assigned, copending U.S. Pat. Application Ser. No. 770,509, filed Feb. 22, 1977. These polymers may be compounded with suitable fillers and additives and fabricated into cured elastomeric articles. The excellent high temperature properties of such elastomers make them especially useful for a wide variety of applications, such as gaskets, seals, wire and cable insulation, and the like. Although carborane-siloxane polymers have excellent high temperature and other high performance characteristics, they are extremely expensive to produce. Hence, it would be an advantage to be able to reclaim the carborane portion from scrap, off-grade or otherwise used-up polymer, and also to recover or regenerate carborane monomer by-products used in forming the carborane-siloxane polymers.
It is known in the art that the carborane icosahedral structure is subject to attack by strong bases. See, for example, Papetti, et al, Inorganic Chemistry, 3 1444 (1964) which discloses without detailed explanation that some cyclic silylated carboranes are cleaved. In addition, Schwartz, et al, Inorganic Chemistry, 4, 661-4 (1955) indicate that a very labile diethoxysilylated carborane is cleaved under acidic or basic conditions not specified.
The present invention provides a technique for highly selectively cleaving carboranyl carbon-silicon bonds in monomeric silylated carboranes and carborane polymers. The method taught herein is highly selective in that the carborane cage contained in these materials may be recovered intact which is highly advantageous due to the expensive nature of the materials involved. Further, this novel technique may be employed in a process for the formation of metal-carborane in bulk when used in combination with known techniques. This represents a significant advance since this method for preparing meta-carborane in high yield in bulk may be practiced on a large-scale, industrial level.


This invention relates to an air conditioning system and more particularly to those having freeze tanks using ice to store cooling power.
Generally, in the past, devices have been used wherein a coolant is partially frozen and the part remaining liquid is used as a coolant. An article describing one of these systems is shown in the September, 1979 issue of Mechanix Illustrated.
Patents which are related to devices of this type are set forth below: U.S. Pat. No. 2,097,556; U.S. Pat. No. 2,158,707; U.S. Pat. No. 2,448,453; and U.S. Pat. No. 2,737,027.


It is a problem with currently available solutions that binaural transmission, i.e. transmission between the two hearing instruments of a binaural hearing aid system, creates an additional latency to the hearing aid processing because of signal buffering, quantization, coding, synchronization, etc. Typically, the hearing instruments may either only transmit or receive audio signals at a given time instant. This means that in order to have hearing instruments operate synchronously within a time slot, the hearing instruments are required to wait until the audio signal packages have been transmitted and received at both hearing instruments.
By only transmitting the audio signal in one direction, such processing delay may be reduced, because waiting for an audio package, which is transmitted in the opposite direction will not be necessary. Therefore, in order to design binaural signal processing algorithms (e.g., binaural noise reduction algorithms) which make use of signals sent only in one direction, there is a need to provide a solution to the problem of how to decide, at any given moment, in which direction (i.e. from which hearing instrument to which hearing instrument) the signal is to be sent.


Universal Mobile Telecommunications System (UMTS) networks have seen an explosive data growth in past few years and, in future, are expected to see continuing growth in the Packet Switched (PS) domain. Beyond data traffic volume growth, an even more aggressive growth in data signaling load has been detected. Among all the signaling messages/procedures on UMTS networks, Radio Access Network (RAN) signaling procedures have caused the most growth and impact. This is due to complicated radio resource sharing techniques required to conserve resources occupied by various users and services.
The majority of RAN signaling events are for connection setup and state transitions (e.g., during Channel Switching). Typically, when a data payload is to be sent from/received by a user equipment (UE), a request is sent to a radio network controller (RNC) to establish a dedicated channel (DCH). Once the data payload is sent or received, multiple inactivity timers are triggered by the RNC and upon expiration of the timers, the RNC transitions the UE from DCH to forward access channel (FACH) and then to IDLE state. To achieve resource efficiency, such timers are often set to short values (cumulatively around 12-16 seconds). Thus, the UE is quickly moved into the IDLE state after completion of a current data session (download and/or upload). Since there is no active data connection between the UE and the core network during the IDLE state, power consumption is minimized. Data applications on the UE initiate multiple data payloads for communication between the UE and RNC. However, the applications operate independently from the radio network perspective, which leads to requesting and establishing multiple independent connections for payloads from different applications. As a result, even though battery life of the UE is conserved, a large number of signaling events are generated and RNC processing load is substantially increased.
In addition to network initiated inactivity-based state transition, UE manufacturers have introduced a fast dormancy (FD) feature that initiates direct transition from DCH to IDLE or FACH to IDLE, before the respective network inactivity timer expires. In this type of system control, the UE proactively releases the data connection, established by the RNC, directly from DCH to IDLE or FACH to IDLE as quickly as possible, to further conserve UE battery life. However, once the UE is in the IDLE state, the data connection must be reestablished to communicate another payload. The reestablishment of the data connection is resource intensive, consumes a high amount of power in the RNC, and can significantly drive up the RNC load.


Particularly for medical purposes, an image which is stored in a storage layer as a latent image is produced from an object, for example a patient, by means of X-ray radiation. It is mostly a phosphor layer which is used as the storage layer in this case. The storage layer is excited by means of a radiation source in order to read out the X-ray image stored in the storage layer. Therefore, on the basis of this excitation the storage layer emits light which has an intensity corresponding to the stored X-ray image. The light emitted by the storage layer is received by a receiving means and subsequently converted into electric signals such that the X-ray image stored in the storage layer can subsequently be visualized. The X-ray image can be displayed, for example, directly on a monitor, or else be written onto a photographic X-ray film which can be used specifically for X-ray images. After the X-ray image has been read out from the storage layer, the latter is erased by an erasing device, in order to be able to store a subsequent X-ray image.
Such storage layers can be arranged in an X-ray cassette. European patent EP 0 288 014 B1 discloses erasing a storage layer which is located in an X-ray cassette. The X-ray cassette contains an opening mechanism such that the X-ray cassette can be opened in order to erase information stored in the storage layer. Present outside the X-ray cassette is an erasing means which outputs an erasure radiation. This erasure radiation is irradiated into the open X-ray cassette and projected onto the storage layer. The irradiation of the storage layer by means of the erasure radiation erases the information stored in the storage layer. The known X-ray cassette contains a reflector or a diffusing means for the purpose of reflecting the erasure radiation irradiated into the cassette, and of scattering it over the width of the storage layer.
A device for reading out information stored in a storage layer is disclosed in patent U.S. Pat. No. 5,038,037. An X-ray table for X-raying patients is described therein. The X-ray table contains two phosphor layers which are fitted on the top side and underside of a tape and serve for storing X-ray information. Both for the phosphor layer fitted on the top side and for that fitted on the underside of the tape, the known X-ray table has a dedicated device for reading out information from this phosphor layer. Furthermore, the X-ray table contains two erasing means which are used to erase the phosphor layers. A dedicated erasing means is provided for each of the phosphor layers. Serving as erasing means is an erasing lamp which—viewed in the transport direction of the tape—is arranged upstream of that point at which the X-ray image of the patient is taken. As a result, an “old” X-ray image stored in the phosphor layer is erased before a “new” X-ray image is taken. A plurality of erasing lamps arranged next to one another are likewise used as erasing means, being arranged in the X-ray table below that position at which the X-ray image is projected onto the stationary tape with the phosphor layers. Before the taping of a “new” X-ray image, the “old” X-ray image is therefore firstly erased with the aid of this erasing means, the tape being stationary. In this type of erasing means, the phosphor layer cannot be used directly for a “new” picture. The erasure of the phosphor layers does not take place until immediately before the subsequent taking of a “new” X-ray image. This means that time is lost and tuning takes place between the operations of erasure and subsequent storage. The erasure must firstly be terminated before the next X-ray image can begin to be taken.
Patent application WO 99/28765 discloses an X-ray cassette in which both a device for reading out information stored in the storage layer and an erasing means for erasing information stored in the storage layer are present. The erasing lamp extends over the entire width of the storage layer in which information can be stored. By means of a drive, the erasing means is guided over the storage layer along a transport direction running perpendicular to the line direction. The storage layer can be erased in this way line by line.


In paper manufacturing processes, cellulose fibers are deposited as an aqueous slurry on a screen. The water is removed to form the paper. Frequently, a dewatering fabric is used in a second stage of water removal from the aqueous slurry.
Eschmann (U.S. Pat. No. 5,204,171) describes a papermaking fabric comprising a blocking layer.
Chuang et al (WO9616305) describes a capillary dewatering method and apparatus.
New fabrics for dewatering during the papermaking process are desired because improved efficiency in water removal can provide cost savings by reducing or eliminating the need for subsequent elevated temperature drying steps. The present invention is directed to these and other important ends.


With the development of multimedia technologies, in an increasing number of application scenarios, multiple devices need to be used to constitute a synchronous playback system for synchronous audio playback, to implement synchronization of sounds played from the multiple devices, so as to implement a function and an effect that are difficult to be implemented by a single device. For example, synchronous audio playback performed by a synchronous playback system constituted by multiple mobile phones can implement effects that cannot be implemented by a single mobile phone, such as multi-channel surround sound and mobile phone speaker array.
In the prior art, an audio playback manner generally used by a synchronous playback system is controlling devices in the synchronous playback system to play an audio file simultaneously. The prior art has the following characteristic, when an audio file is played in a synchronous playback system, the audio file is generally divided into several audio clips, and then the audio clips are played one by one. However, playback of each audio clip requires processing procedures such as decoding, audio mixing, digital signal processing (DSP), and output, and therefore, there is a time difference from start of playback of an audio clip to actual generation of a sound, and this time difference is a playback delay. A value of the playback delay is determined by a hardware configuration and a software environment of a device, and when hardware configurations or software environments of various devices are different, values of playback delays are also different.
Because playback delays of various devices are different, when various devices start to play a same audio clip simultaneously, sounds are actually generated by the various devices at different time points. When hardware configurations or software environments between various devices differ greatly, a time deviation in actual generation of sounds also becomes large. For example, in a case in which a HUAWEI MATE1 mobile phone and a HUAWEI HONOR mobile phone start to decode a same audio clip simultaneously, a time difference in actual generation of sounds may be 130 milliseconds (ms) to 168 ms. Further, a time deviation between various devices is generated when each audio clip is played, and with an increasing number of played audio clips, the time deviation in actual generation of sounds between various devices gradually accumulates. As a result, the problem of time inconsistency between various devices in actual generation of sounds becomes increasingly serious, which makes it difficult to implement synchronous audio playback.


The present invention is directed toward a portable golf practicing device and more particularly toward a golf club having a telescoping shaft and a ball retrieval system such as a fishing reel attached thereto.
Golf clubs with telescoping shafts have been proposed in the past. One such golf club is shown, for example, in U.S. Pat. No. 3,424,464. This patent shows a golf club in the form of a putter which has a telescoping shaft and which is intended primarily as a novelty item. The putter is mounted on a small stand which has an open front and can, therefore, function as a practice cup. Thus, the putter can actually be used by an executive or the like practicing putting in his office.
A golf club with a telescoping shaft is also shown in U.S. Pat. No. 2,107,983. This patent is directed toward a club which is intended to be actually used on a golf course and which can be adjusted during the course of play to the effective length desired without materially disturbing the balance of the club. This patent, as with the prior patent described above, is directed toward a golf club only and includes no means for retrieving a ball after it has been hit.
Golf clubs have also been proposed which include retrieval devices in combination therewith so that a ball can be retrieved after it has been hit. These prior devices include fishing reels attached near the handle of the golf club as shown, for example, in U.S. Pat. Nos. 3,065,563 and 4,526,374.
The first-mentioned patent includes a fishing reel which is relatively permanently fixed to the golf club handle and the shaft of the golf club includes a plurality of eyelets secured thereto for guiding the line. The second patent, on the other hand, includes a fishing reel carried by its own bracket which is adapted to be secured to substantially any golf club. In both cases, the end of the line is secured to a golf ball.
While each of the devices shown in U.S. Pat. Nos. 3,065,563 and 4,526,374 show the use of a retrieval device in the form of a fishing reel, the devices are used on substantially conventional golf clubs. There is no suggestion in these patents that the golf club be provided with a telescoping shaft. Furthermore, the fishing reels must be manually rewound in order to retrieve the ball after it has been hit. No automated means for retrieving the ball is proposed.


In the art of deposition of films of material onto a surface of a substrate, there are many known techniques, including vacuum evaporation deposition, ion plating, ion- and plasma-assisted sputtering or chemical vapor deposition ("CVD"), and the more modern ICB approach. ICB deposition is an ion-assisted technique in which the material to be deposited on a substrate is heated in a crucible and its vapor ejected through a small nozzle into a vacuum region. The vapor forms loosely-held atomic clusters, each cluster comprising 100 to 2000 atoms of the material. Some of the ejected vaporized atomic material is ionized by electron bombardment and the atoms are accelerated toward the substrate disposed in the vacuum region. The ionized material, together with the neutral (i.e., non-ionized) component of the vapor, arrive at the substrate surface for deposition thereon. ICB deposition offers the ability to precisely control the deposited film structure by applying kinetic energy to the vapor clusters during film deposition. Kinetic energy control is achieved by varying the acceleration voltage and the electron current for ionization.
In most of the known ion- and plasma-assisted deposition techniques, the individual atoms of the material to be deposited on the substrate generally impact the substrate surface with excessive kinetic energy, producing a relatively high number of defects in the substrate and/or the deposited film. With ICB deposition, a more useful lateral energy is obtained as the clusters impact the substrate and the atoms break off, without damaging the film and substrate. Due to the effects of ionized cluster bombardment, ICB deposition produces films with high density, strong adhesion, a low impurity level, and a smooth surface. Also, film properties usually associated with relatively high substrate temperatures in conventional vacuum depositions can be obtained at lower substrate temperatures in the ICB technique. This results in a distinct advantage in semiconductor device fabrication. See, for example, U.S. Pat. Nos. 4,152,478, 4,217,855, 5,350,607 and 5,380,683, all of which are hereby incorporated by reference.
The trend in the semiconductor manufacturing industry has always been to increase the number of active devices (e.g., transistors, resistors, capacitors) formed in an area of a semiconductor substrate (e.g., silicon, germanium, gallium arsenide). This increase in IC density has been achieved primarily by decreasing the size of the active devices and associated electrically-isolating areas (e.g., field oxide) formed within the IC substrate. Sizes of such devices and areas are now down into the submicron range. This size reduction has been achieved largely through improved fabrication methodologies and structures.
For example, it is common to employ one or more thin horizontal layers of a high-conductivity metal (e.g., aluminum), separated by insulating layers, together with associated vertical, high-conductivity interconnecting plugs or vias routed through the insulating layers. This is to connect between the active devices in the semiconductor substrate. In this approach, holes are formed in the insulating layers at desired connection points. The holes are filled with a high-conductivity, low-resistivity material to form the vias. The overlying horizontal metallization layer is then deposited. This process is repeated for subsequent vertical plugs and horizontal overlying layers. In this way, an ohmic contact is formed between active device areas (e.g., the source and drain terminals of an MOS transistor, or the collector, base and emitter terminals of a bipolar transistor) in the silicon substrate. Interconnections can be made in the different metal layers as cross-overs, thereby further increasing IC density. This interconnect process is generally referred to as "metallization".
However, conventional metallization techniques encounter problems as device geometries become increasingly smaller. For example, as device sizes shrink, contact or via holes formed closer together, are of smaller diameter and have steeper vertical sidewalls. As a result, it has become difficult to accurately deposit conventional materials, such as aluminum, using conventional techniques (e.g., sputtering), into the holes to achieve uniform contact with device contact areas and metallization layers. Non-uniform contact within the interconnects results in problems such as non-planar topographies and electrical breaks formed at the edges of the holes. The result is manifested in relatively poor step coverage of the metallization layers and vias. Other problems include those related to the reliability of the interconnect lines, such as electromigration or wear-out failures.
Also, as device sizes shrink, connection lines become smaller, thereby subjecting the interconnects to higher current densities. At these higher densities, aluminum metallization layers and plugs are increasingly susceptible to stress migration and electromigration damage. Further, conventional metallization materials such as aluminum exhibit higher resistance, which increases the RC time constants of the device, thereby limiting overall device speed.
In an attempt to overcome these problems, it is known in the prior art to utilize tungsten as the material comprising the metallization layers and/or the plugs, or as a separate, additional barrier layer utilized in conjunction with an aluminum layer or plug. Tungsten is utilized in part because, relative to aluminum, tungsten has a higher resistance to electromigration. The tungsten barrier layer acts as a backup layer, maintaining the electrical connection integrity of the metallization layers and plugs if the primary aluminum layers and plugs fail due to stress migration and electromigration. Still further, tungsten can be deposited somewhat more uniformly than aluminum, thereby reducing the aforementioned concerns with step coverage.
However, an inherent problem with the use of tungsten alone as the material comprising the metallization layers and plugs is that tungsten has approximately three times the resistivity of aluminum. Therefore, it is desired to utilize tungsten as the primary constituent of a tungsten alloy formed as a metallization layer or plug, and to deposit the tungsten alloy layer onto a semiconductor substrate using the ICB approach.


Securing items during transport from one location to another location can be difficult for those without a vehicle. Depending on the distance from the retailer, the act of transporting the items can be physically demanding and frozen items can melt or defrost along the way.


2-bromo-4,6-dinitromesitylene may be used as a starting material to form a number of compounds, such as for example 2-perfluoroalkyl-4,6-diaminomesitylene, which in turn may be used as one of the main constituents in polyamides, polyimides, urethanes, ureas, and the like.
2-bromo-4,6-dinitromesitylene has been prepared so far by reacting nitric acid or a mixture of fuming sulfuric and nitric acids with bromomesitylene. Such preparations are shown for example in very old as well as more recent references, such as "Fittig and Storer, Liebigs Ann. Chem., 147, 1-11 (1868)", "Suessenguth, Liebigs Ann. Chem., 215, 242-252 (1882)", and "Adams and Miller, J. Amer. Chem. Soc., 62, 53-56 (1940)."
The following is translated from Fittig and Storer (p. 8): "By pouring fuming nitric acid over bromomesitylene at ambient temperature and after short standing, it is converted into the (title) compound, which through washing with water and recrystallization with alcohol is easily purified. It crystallizes in fine, colorless needles, which dissolve little in cold alcohol, easier in hot alcohol, yet are much less soluble than the starting compound. Its melting point is 189.degree.-190.degree. C. Under warming, the compound develops a genuine musk smell."
______________________________________ Analysis: Calculated Found ______________________________________ C9 108 37.37% 37.16% H9 9 3.11 3.29 Br 80 27.68 27. 2 NO.sub.2 92 1.84 -- 289 100.00 ______________________________________
This preparation appears to be simple and leading to a pure product, since there are only two positions in the aromatic ring of bromomesitylene, which are open for substitution by nitro groups. Simple elemental analysis, indicates the reaction to be clean and straightforward. However, more careful examination of this reaction reveals it to be considerably more complicated.
Depending on how the reaction is conducted, a number of undesirable by-products, such as 2,4,6-trinitromesitylene, 2,4-dibromomesitylene, and 2,4-dibromo-6-nitromesitylene, are formed. Some of these by-products are extremely difficult to separate, because they cocrystallize with the desired product, even upon repeated recrystallization from a variety of solvents. These by-products may also prove to be catastrophic to polymers intended to be made from derivatives of the main product (dinitro compounds) after hydrogenation (diamines), since monoamine derivatives will serve as chain terminators, and triamine derivatives will serve as crosslinkers. Thus, expensive procedures, such as repeated crystallizations, sublimations, and the like are needed for purifying the products obtained in subsequent conversions of impure 2-bromo-4,6-dinitromesitylene, to free these products from undesirable impurities.
In contrast to previous attempts, considerably purer 2-bromo-4,6-dinitromesitylene may be prepared according to the methods of the present invention.


1. Field of the Invention
The present invention relates to an air-controlled support for a vehicle seat and, more particularly, to an air-controlled lumbar support apparatus for use in a vehicle seat.
2. Description of the Prior Art
A conventional air-controlled lumbar support apparatus is disclosed in U.S. patent application Ser. No. 4,190,286 to Bentley. An example of the conventional apparatus is shown generally in FIG. 1 and includes a vehicle seat 10 with a backrest 12 having a series of inflatable chambers 14. Each of the inflatable chambers 14 is connected to a valve mechanism 16 by individual tubes 18. The valve mechanism 16 controls the intake and exhaust of the air within the inflatable chambers 14. Additional air is supplied to the inflatable chambers 14 by means of an air pump 20, which delivers the air supply through the valve mechanism 16.
Since several inflatable chambers 14 are installed within the backrest 12 of the seat 10, the valve mechanism 16 requires a series of valves (not shown) for controlling the intake and exhaust of air to the inflatable chambers 14. As a result, the valve mechanism 16 typically is oversized and unduly complicated. Furthermore, the valve mechanism 16 and the air pump 20 must be independently mounted on the seat 10. Therefore, considerable space is required to position the tubes 18, the valve mechanism 16, the inflatable chambers 14 and the air pump 19 in reasonable proximity to each other.


1. Field of the Invention
This invention relates to display systems utilizing holographic lenses and more particularly to a display system incorporating a holographic lens constructed with aberrated wavefronts which is used in conjunction with other optical elements including cylindrical, tilted and decentered surfaces to provide correction of the aberrations in the holographic lens.
2. Description of the Prior Art
Previously, optical systems utilizing holographic lenses have been designed with good image quality over small fields of view and poor image quality over large fields of view. Also, optical systems utilizing holographic lenses have been required to operate at relatively small off-axis angles because of the aberrations inherent in a holographic lens utilizing large off-axis angles. Aberrations arise for the on-axis image point in a holographic lens designed for a large field of view because the wavefront used in the reconstruction process is not identical to either construction beam. This arises because there is a pupil-to-pupil relationship between the construction beam sources while an object-to-image relationship must hold upon reconstruction. The holographic lens is constructed with coherent sources located close to or at the desired entrance and exit pupil locations of the holographic lens so that the Bragg condition is met for the chief rays, thus providing a high reconstruction efficiency across a large field of view. The principal aberrations in a holographic lens constructed as above and operating at a relatively large off-axis angle are axial astigmatism, axial coma and an assymetric variation of coma and astigmatism across the field. In addition there is a considerable amount of field tilt and distortion. The assymetric variation of astigmatism arises principally because the field tilt for fans of rays traced in a vertical plane is different from the field tilt for fans of rays traced in a horizontal plane. Unless compensation is provided for the aberrations in the holographic lens operating at a relatively large off-axis angle, the display provides a very poor image quality that may be unsatisfactory for operations such as helmet-mounted displays or aircraft head-up displays.


Magnetic discs and disc drives provide quick access to vast amounts of stored information. Both flexible and rigid discs are available. Data on the discs is stored in circular tracks and divided into segments within the tracks. Disc drives typically employ one or more discs rotated on a central axis. A magnetic head is positioned over the disc surface to either access or add to the stored information. The heads for disc drives are mounted on a movable arm that carries the head in very close proximity to the disc over the various tracks and segments.
The increasing demands for higher areal recording density impose increasingly greater demands on thin film magnetic recording media in terms of coercivity (Hc), remanent coercivity (Hr), magnetic remanance (Mr), which is the magnetic moment per unit volume of ferromagnetic material, coercivity squareness (S*), signal-to-medium noise ratio (SMNR), and thermal stability of the media. These parameters are very important to the recording performance and they depend primarily on the microstructure of the materials of the media. For example, as decreasing the grain size reduces the SMNR or reducing exchange coupling between grains, it has been observed that the thermal stability of the media decreases.
The requirements for high areal density, i.e., higher than 30 Gb/in2, impose increasingly greater requirements on magnetic recording media in terms of coercivity, remanent squareness, medium noise, track recording performance and thermal stability. It is extremely difficult to produce a magnetic recording medium satisfying such demanding requirements, particularly a high-density magnetic rigid disk medium for longitudinal and perpendicular recording.
As the storage density of magnetic recording disks has increased, the product of Mr and the magnetic layer thickness t has decreased and Hr of the magnetic layer has increased. This has led to a decrease in the ratio Mrt/Hr. To achieve a reduction in Mrt, the thickness t of the magnetic layer has been reduced, but only to a limit because the magnetization in the layer becomes susceptible to thermal decay and medium noise.
Medium noise in thin films is a dominant factor restricting increased recording density of high-density magnetic hard disk drives, and is attributed primarily to inhomogeneous grain size and intergranular exchange coupling. Accordingly, in order to increase linear density, medium noise must be minimized by suitable microstructure control.
Longitudinal magnetic recording media containing cobalt (Co) or Co-based alloy magnetic films with a chromium (Cr) or Cr alloy underlayer deposited on a non-magnetic substrate have become the industry standard. For thin film longitudinal magnetic recording media, the desired crystallized structure of the Co and Co alloys is hexagonal close packed (hcp) with uniaxial crystalline anisotropy and a magnetization easy direction along the c-axis that lies in the plane of the film. The better the in-plane c-axis crystallographic texture, the more suitable is the Co alloy thin film for use in longitudinal recording to achieve high remanance and coercive force. For very small grain sizes coercivity increases with increased grain size. The large grains, however, result in greater noise. Accordingly, there is a need to achieve high coercivities without the increase in noise associated with large grains. In order to achieve low noise magnetic recording media, the Co alloy thin film should have uniform small grains with grain boundaries capable of magnetically isolating neighboring grains thereby decreasing intergranular exchange coupling. This type of microstructural and crystallographic control is typically attempted by manipulating the deposition process, and proper use of underlayers and seedlayers.
It is recognized that the magnetic properties, such as Hcr, Mr, S and SMNR, which are critical to the performance of a magnetic alloy film, depend primarily upon the microstructure of the magnetic layer, which, in turn, is influenced by the underlying layers, such as the underlayer. It is also recognized that underlayers having a fine grain structure are highly desirable, particularly for growing fine grains of hcp Co alloys deposited thereon.
For high signal to noise ratio (SNR) magnetic recording media, it is desirable to have a high signal in a very thin film. Higher signal can be achieved by increasing the saturation magnetization (Ms) of the material at the top of the magnetic layer, and correspondingly increasing the fringing magnetic field that provides signal. Prior art magnetic recording systems generally employ media including a magnetic layer alloy including Co and Cr, and other elements often including Pt, and B. These magnetic layer systems generally require 10-25% Cr, and often use 5-15% B in order to isolate the magnetic grains in the magnetic layer and reduce noise.
There exists a continuing need for high areal density longitudinal magnetic recording media exhibiting high Hcr and high SMNR while overcoming the deficiencies of the prior art solutions.


Speech is a natural form of human expression. Irrespective of age, whether it's a small child or a grown up individual, speech comes naturally to humans and is “the” mode of human interaction. Realizing this preferred mode of human interaction, computer scientists have extended this natural form of human interaction to computing systems, and over the years speech recognition systems have evolved considerably in recognizing human speech. Therefore, whether it's a simple command application or a dictation system, speech recognition systems have become quite useful in human-computer interaction. However, one problem with any speech system is spurious speech recognition, especially in a noisy environment, such as, traffic or a factory establishment. Spurious or background noise severely impacts the ideal use of a speech recognition system and creates difficulties during interaction. This affects the system's reliability since the speech recognition system is unable to distinguish between a speech input and a spurious input.


1. Statement of the Technical Field
The present invention relates to the field of markup language processing, and more particularly to the processing of frames in markup language.
2. Description of the Related Art
Conventional markup can be visually presented through use of a content browser. Content browsers process display attributes embedded in markup to properly format content also contained within the markup. Notable variants of the content browser include the venerable Web browser, as well as the more recent extensible markup language (XML) browser. Regardless of the type of browser, all conventional markup processors are preconfigured to parse and interpret attribute tags embedded in markup. Examples of attribute tags include the well-known hypertext markup language (HTML) tags, <HEAD>, <BODY>, <H1>, <P>, <HREF>, <HTML> and <FRAMESET>.
In regard specifically to the <FRAMESET> attribute tag defining a set of displayable frames, many content distributors have incorporated frames in the design of Web pages, as frames allow Web sites to organize the presentation of disparate information in a logical and unified manner. Often, the enablement of multiple, scrollable regions of a single Web page forms the basis for the use of frames within the Web page. For example, it is known to use one frame to present a menu, while a second, adjacent frame can display the content associated with a particular menu choice. As another example, the results of a query can be presented in a first, scrollable frame, while the content associated with a particular result can be presented in an adjacent frame.
While frames can provide the benefit of screen organization and scrolling, frames can pose some difficulty in the support of bidirectional environments. Bidirectional environments relate to the directional manner in which information can be presented in an electronic document. Specifically, western languages such as English present information visually from left to right. In contrast, middle-eastern languages such as Hebrew and Arabic present information visually from right to left. In the course of undertaking internationalizing the presentation interface of computer software, solutions have been proposed which address the problem of bidirectional text. For instance, in one solution, text can be rearranged in a display window according to the underlying language associated with the character codes of each word in the text.
Other internationalization solutions address not only the underlying directional orientation of text, but also the arrangement of user interface controls in a graphical user interface. For example, in Kaplan, Internationalization with Visual Basic, (SAMS 199x), check boxes, labels, option buttons and text boxes can be horizontally “flipped” in terms of orientation to accommodate a bidirectional environment. The particular user interface control elements which can be flipped in the Kaplan reference, however, are flipped inasmuch as those control elements usually accompany text—hence the need to re-orient the control. By comparison, the teachings of Kaplan explicitly inhibit the re-orientation of other user interface controls such as combo boxes, command buttons, scroll bars, list boxes, picture boxes and, most importantly, frames.
While the use of frames in a conventional GUI as described in the Kaplan reference rightfully inhibits the re-orientation of frame elements because frames play little role in the GUI of a stand-alone application, the same cannot be said of an application whose interface relies upon the presentation attributes of a markup language. Specifically, frames play a crucial role in the presentation interface of a markup language defined user interface. Thus, in the context of markup, the directional implication of a language is not merely limited to the characters which form a word, or the words which form a sentence. Rather, the directional implication of a language can include the layout of the frames within the document itself. More particularly, in a right to left orientation, it can be preferable to horizontally re-orient adjacent frames in a content browser to accommodate a right-to-left environment.
Unfortunately, existing content browsers and markup languages do not account for bidirectional documents. In fact, in the HTML specification, while the “dir” attribute can specify a directional orientation, including “rtl” and “ltr”—right to left and left to right, respectively—the HTML specification cannot account for a document whose orientation can vary from right to left and left to right. Rather, to accommodate the bidirectional circumstance, separate markup must be maintained for both cases of left to right and right to left configurations. As one skilled in the art will recognize, however, maintaining two sets of markup to support the presentation the same content in different directional orientations requires the maintenance and synchronization of both sets of markup—a distinctly undesirable solution.


1. Field of the invention
The present invention relates to landscape edging used to demarcate areas of lawns, gardens and the like, and more particularly to an illuminated landscape edging.
2. Description of the Prior Art
Landscape edging is very widely used to provide demarcation between areas of lawns, gardens and the like. For instance, landscape edging may be used to form a barrier between botanical types, wherein, for example, on one side thereof is a lawn and on the other side thereof is a flower garden. In order to provide a barrier to passage therethrough of flora, landscape edging is implanted into the ground along the line of selected demarcation, and a portion thereof is located above the surface of the ground.
One very common type of landscape edging is depicted in FIG. 1. This prior art landscape edging 10 is characterized by a planar member 12 which is structured to be implanted into the ground and by a tubular member 14 which is structured to be located above ground. The planar member 12 is provided with a medial ribbing 16 and usually provided with an end hook 18. Both the medial ribbing 16 and the end hook 18 serve to anchor the planar member into the ground. This prior art landscape edging 10 is constructed of a plastic material, which is believed to be invariably black and opaque. The prior art landscape edging is elongated and is supplied in long rolls which may be cut into sections to suit the length needs of a particular landscaping job. Sections of the prior art landscape edging are serially joined by a tubular connector 20 inserting into open ends of adjoining tubular members 14.
Increasingly, homeowners are installing landscape lighting to illuminate their lawns and other landscape features. Usually, this form of illumination is in the form of a series of discrete lighting units which are partly implanted into the ground and which operate on a low voltage line supplied from the home utility service. These units can sometimes be the target of vandals or may be the accidental victims of an untoward incident, such as being hit by a lawn mower.
What is needed in the art is to somehow combine the benefits of landscape edging with the attractiveness of landscape lighting.


1. Field of the Invention
The present invention relates to a laminated gas sensor element, a gas sensor equipped with the laminated gas sensor element, and a method for manufacturing the laminated gas sensor element.
2. Description of the Related Art
Conventionally, known gas sensors include those for detecting a particular gas component contained in exhaust gas or for measuring the concentration of the particular gas component. Some of these gas sensors employ a laminated gas sensor element configured such that a pair of electrodes are provided on a solid electrolyte body. The solid electrolyte body of zirconia or the like used in the gas sensor element becomes active at a high temperature of 300° C. or higher. Usually, the gas sensor element is used in an activated state upon heating by a heater laminated on the solid electrolyte body. In this case, adhesion, to the gas sensor element, of a water or oil droplet contained in a gas to be measured (hereinafter, also referred to as adhesion of water) may generate a crack in the gas sensor element due to thermal shock. According to a known technique for solving this problem, a distal end portion (detecting portion) of the gas sensor element which is exposed to a gas to be measured is protected with a porous protection layer. For example, Patent Document 1 discloses a technique for restraining the generation of a crack at corner portions of a gas sensor element by increasing the thickness of a protection layer at the corner portions, which are susceptible to the generation of a crack.
[Patent Document 1] Japanese Patent Application Laid-Open (kokai) No. 2003-322632
3. Problems to be Solved by the Invention
However, even in the case of a laminated gas sensor element whose detecting portion is protected with a porous protection layer as in the case of Patent Document 1, the protection layer may fail to provide sufficient protection. Namely, adhesion thereto of a larger amount of water droplets or oil droplets contained in a gas to be measured (adhesion of water), potentially results in the generation of a crack in the laminated gas sensor element due to thermal shock.


The present invention relates to a new and distinct cultivar of Begonia plant, botanically known as Begonia hybrida, commercially referred to as a Rex Begonia and hereinafter referred to by the name ‘KRBELSS01’.
The new Begonia plant is a product of a planned breeding program conducted by the Inventor in Ermelo, The Netherlands. The objective of the breeding program is to create new Rex Begonia plants with unique and attractive leaf coloration.
The new Begonia plant originated from a cross-pollination made by the Inventor in Ermelo, The Netherlands in January, 2009 of a proprietary selection of Begonia hybrida identified as code number KV07B0399-003, not patented, as the female, or seed, parent with a proprietary selection of Begonia hybrida identified as code number KV06B0370-002, not patented, as the male, or pollen, parent. The new Begonia plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in Ermelo, The Netherlands in January, 2010. Asexual reproduction of the new Begonia plant by leaf cuttings in a controlled greenhouse environment in Ermelo, The Netherlands since February, 2010 has shown that the unique features of this new Begonia plant are stable and reproduced true to type in successive generations.


Fluid flow pipe systems provide the infrastructure necessary to accommodate the flow of fluids, such as, liquids, gases, or slurries, etc, in residential and commercial applications. For example, such systems are commonly found in residential homes, office buildings, factories, car washes, swimming pools, irrigation installations, septic installations, etc.
Regardless of the applications, most fluid flow pipe systems share certain common elements, such as:                (a) pipes: pipes are hollow cylindrical members configured to conduct or transfer fluids. Pipes may comprise metal materials (e.g., carbon steel, stainless steel, copper, copper alloys, copper-nickel, etc.) or plastic materials (e.g., PVC, CPVC, UPVC, FRP, FRE PEX, etc.);        (b) pipe fittings: pipe fittings are attachments that are placed or affixed to the end pipe ends to provide versatility in changing the direction of fluid flow, distribution, increase or decrease flow capacity and interconnections. Pipe fittings may comprise a variety of configurations (e.g., elbows, bends, returns, tees, crosses, reducers, end caps, plugs, nipples, unions, couplings, bosses, etc.);        (c) valves: valves are mechanical devices configured to control the flow and pressure within the pipe system (e.g., gates, globes, plugs, balls, butterflies, checks, diaphragms, pinches, pressure reliefs, control valves, etc.;        (d) fixtures: fixtures are elements or amenities disposed at the end of pipe runs (e.g., faucets, toilets, showers, bidets, spigots, sprinklers, icemakers, etc.); and        (e) pipe system service equipment: such equipment includes, but not limited to, water heaters, filtration units, desalinization units, water softeners, back-flow preventers, sump-pump units, etc.
For a variety of reasons, including but not limited to, environmental conditions, rust/corrosion, pressure variations, component fatigue/failure, substandard installation practices, etc., it is not uncommon for elements of fluid flow pipe systems to deteriorate or become defective, thereby requiring repair or replacement servicing. Repair/replacement servicing often requires that the fluid in the locally-affected area or defective equipment, or sometimes in the entire pipe system infrastructure, be sufficiently evacuated prior to the repair or replacement, resulting in time-consuming delays, inefficiencies, and customer inconvenience.


1. Field of the Invention
The invention relates to degaussing coils or degaussers designed to be fitted into cathode-ray tubes for color televisions. The degaussing coil is constituted by a winding of enamelled electrical wire shielded by a heat-sealed insulator sheath. This wire is fastened to the glass fixtures of the mask picture tube and it is connected to the electrical circuit of the television set by a pair of conductors that end in a bipolar connector. The conductors are electrically connected to the two ends of the winding in a region that is not covered by the insulator sheath. This uncovered region is then confined in an insulating envelope that ensures the electrical shielding and the mechanical strength of the connected parts. The envelope can be formed by taping or by two shells of synthetic organic resin forming an interconnection case.
2. Discussion of the Background
Coils manufactured according to taping techniques or by the positioning of a case require equipment whose difficulty of handling entail considerable extra costs. These coils may have a defect in the sealing quality at the interconnection and they lack aesthetic quality.


A lens array optical system including a plurality of lens portions is used for an imaging lens for a compound-eye imaging apparatus, a secondary image forming lens in an autofocus module of a single-lens reflex camera, an illumination lens in a semiconductor exposure apparatus, a condenser lens in a liquid crystal projector panel, and the like. The lens array optical system can be manufactured at low cost with optical plastic having high processability. However, the optical plastic not only has a high thermal expansion coefficient bus also is inferior in durability and light transparency, and accordingly is not suitable to be used stably on a high-temperature or high-humidity severe condition. Therefore, optical glass that has a low thermal expansion coefficient and is superior in durability under high temperature or high humidity is required to be used for the lens array optical system in order to enable stable use in various environments.
As a method for manufacturing a lens array optical system made of optical glass having multiple spherical or aspheric lenses, a method is proposed in which preforms made of glass with a larger curvature than a concave curvature of a forming die are placed, one by one, in transfer portions and are hot stamped (refer to Patent Literature 1). An excess of the preforms over the volumes of cavities for forming optical surfaces of the multiple lenses flows into junctions of the cavities and are integrally fused. However, there is a problem with the method of Patent Literature 1 that it takes much time and trouble to place the preforms on the optical transfer surfaces on the die. Moreover, air may remain in the junction (fused portion or joint) due to variations in the preforms to result in a reduction in the strength of the junction of the preforms. Moreover, there is also a problem that as the number of lens portions increases, the forming process becomes more difficult, and accordingly it becomes impossible to obtain a lens array having an intended optical surface shape.
Moreover, as another method for manufacturing a lens array optical system, a method is also proposed which does not use a die, supplies a liquid material to a substrate where a plurality of through-holes is formed, and forms a plurality of lenses on the substrate (refer to Patent Literature 2). However, there is a problem with the method of Patent Literature 2 that it is difficult to form an optical surface of the lens into an aspheric shape so that it is not possible to appropriately design the optical surface of the lens portion and optically correct various aberrations.
Moreover, as another method for manufacturing an optical glass lens array optical system, the drop method is known which forms a lens by dropping molten glass into a die. The drop method has few constraints on the shape of an optical surface since the forming process is performed in a state where the viscosity of the glass is relatively low. Moreover, a reduction in the occurrence of forming failure ascribable to the fluidity of a material can be expected. As the method for manufacturing a lens array by the drop method, Patent Literature 3 describes a method for manufacturing a lens array having 2×2 lens portions by dropping a glass drop on the center of one of dies having 2×2 optical transfer surfaces and pressing it with the other die. However, Patent Literature 3 does not describe the production of a lens array having lens portions more than 2×2, such as 4×4 or 5×5, in a lattice form. If an attempt is made to obtain a lens array having 4×4 lens portions by dropping a glass drop on a center portion of, for example, 4×4 optical transfer surfaces in accordance with the manufacturing method described in Patent Literature 3, an optical transfer surface that has been insufficiently filled with the glass may be produced as described below. Moreover, in Patent Literature 3, a projection is provided to change the flow of the glass drop to make adjustments such that the glass drop flows along the transfer surface of an optical surface near its edge side close to the projection, the edge side having a large inclination angle. Accordingly, an attempt is made to transfer the optical surface with high accuracy. However, there are problems that the manufacturing cost may increase if a glass projection is provided to the die as a preliminary process, and the die processing cost is high and the life of the die is influenced if the projection is formed upon die processing. If an attempt is made to drop a plurality of glass drops individually and respectively onto the optical transfer surfaces, forming failure may be invited, or gas entrainment may occur upon reaching the die, due to time differences in die arrival timings among the glass drops. Moreover, a problem also arises in which it becomes difficult to perform a forming process by pressing to a desired thickness since it becomes easy to become cold and harden as the result of a reduction in the volumes of the individual glass drops.