1. Field of the Invention
The present invention relates to a technology for realizing low damage sputtering regardless of materials (such as, an inorganic or organic material) in a surface analysis method, and relates to a technology for realizing improvement of sensitivity by improving secondary ion yield in a secondary ion mass spectroscopy method.
2. Description of the Related Art
An ion source for surface analysis that can perform sputtering without any damage to a target sample has not yet been developed. In the surface analysis, argon ion (Ar+) is the most common ion species for sputtering, but it is known that the occurrence of damage due to the sputtering is high.
In addition, in a secondary ion mass spectroscopy method (SIMS) as one of surface analysis methods, a primary ion beam that has been used so far is a noble gas ion or a metal ion (Cs+, Ar+, Ga+, Au+, or the like). Some of them can be reduced to a small beam in the order of several tens nanometer, but the occurrence of large damage to a sample is a common drawback.
In addition, if these ions are used as a primary ion source, secondary ion yield is very low, and secondary ion generation efficiency is low. Therefore, in order to overcome the drawback of the SIMS using them as the primary beam, a cluster ion SIMS has been developed. A beam source thereof is Au3++, Bi3++, or the like. By using the cluster ion (Au3++, Bi3++, or the like) consisting several atoms, desorption efficiency of the secondary ions is significantly increased in a non-linear manner. Such result is due to the generation of ablation.
On the other hand, because a target sample surface and its vicinity are significantly damaged, application of the conventional system to a biological material is difficult; and nondestructive observation of molecule ions is difficult; specifically, the sample receives large fragmentation, and a surface of the sample is decomposed and polymerized.
A cluster ion source of C60+ ion is commercialized; and hence, a low damage sputtering technology is realized though in a limited manner. Further, the desorption efficiency is further increased in the SIMS using the C60+ ion source as the primary ion source. However, the following phenomena are caused: (1) an inorganic material is contaminated with a carbon component derived from C60; (2) craters are generated in a surface of the material so that surface destruction occurs; (3) a biological sample or the like is significantly damaged; and (4) the secondary ion yield is low in the SIMS, and when the beam diameter is decreased, ionic strength is weakened so that utility value as the SIMS is deteriorated (particularly in an organic material). Refer to Japanese Patent Application Laid-open No. 2005-134170, Journal of Physical Chemistry B, 108, pp 7831-7838, and Applied Surface Science 231-232, pp 936-939, FIG. 4.
There is a surface analysis method utilizing a gas cluster ion beam (GCIB) that has been recently popular, in which noble gas (such as argon (Ar)) is ejected in vacuum to form a jet stream, gas temperature is decreased, and neutral clusters having an n value of Arn+ of a few thousands to a few tens of thousands are formed and ionized to generate Arn+, which is accelerated to impact the sample.
With this method, depth profile analysis with low-damage sputtering for an organic material (such as a polymer) is confirmed to be effective and is commercialized. However, for an inorganic material (such as a ceramic material) that is relatively hard, the sputtering speed is extremely slow so that it is not practical. Therefore, a range of the sample types to be analyzed is inevitably limited to mainly organic industrial materials.
In addition, when the GCIB is used as the primary ion source in the secondary ion mass spectroscopy method, it is known that the secondary ion yield thereof is low; and hence, it is not practical when used for improving sensitivity in the secondary ion mass spectroscopy method. Refer to Japanese Patent Application Laid-open No. Hei 04-354865, Japanese Patent Application Laid-open No. 2008-116363, and Analytical Chemistry, 2011, 83(10), pp 3793-3800, FIG. 7.
In addition, an ion beam technology using a charged droplet method has been developed. In this method, a capillary is disposed in the atmosphere, solvent is supplied through inside of the capillary, and an extraction electrode that is applied with a high voltage negative with respect to the capillary is disposed in front of the capillary so as to generate ions in the atmosphere.
A vacuum chamber is separated into several steps from low vacuum side to high vacuum side with small diameter orifices. The ions are made to pass through the orifices and are transported to vacuum atmosphere so as to be used as ion beam. In this case, the cluster ions generated in the atmosphere inevitably collide with gas molecules in the atmosphere so that many ions are scattered. Therefore, the amount of ions that are actually transported to the vacuum side and can be effectively used is small; and in addition, downsizing of the cluster ion (fission of the cluster) also occurs due to vaporization in the atmosphere side.
In addition, to use the ion beam, it is necessary to apply a high voltage, which is positive with respect to the ground potential, to the capillary as a source, and it is also necessary to apply a high voltage to parts for lens effect or the like in a low vacuum region during the ion transportation process. Therefore, discharge phenomenon tends to occur in various parts. Consequently, it becomes difficult to stably obtain the ion beam, and it is also difficult to decrease the beam size to be small.
On the other hand, a differential pumping system for evacuating the separated vacuum chamber also becomes large in scale which causes difficulty when in use. Refer to Japanese Patent Application Laid-open No. 2011-141199.
Consequently, a practical ion source that can support various types in etching layer-by-layer without damaging a surface of the sample after irradiation has not been developed yet, and an ion source succeeding in dramatic improvement of sensitivity in the secondary ion mass spectroscopy method has also not yet been developed.
A charged droplet ion source of the related art is described below. In FIG. 5, a charged droplet ion source 701 includes a vacuum chamber 710.
The vacuum chamber 710 is connected to first and second vacuum evacuating devices 729a and 729b so that the inside of the vacuum chamber 710 can be evacuated.
An extracting electrode 721 is provided with a small hole (orifice) so that gas flows in the vacuum chamber 710 through the extracting electrode 721 when the inside of the vacuum chamber 710 is evacuated. First, the inside of the vacuum chamber 710 is evacuated by the first and second vacuum evacuating devices 729a and 729b.
An emission tube (capillary) 703 is disposed outside the vacuum chamber 710.
The distal end of the emission tube 703 is directed towards the small hole of the extracting electrode 721; and a base part thereof on the opposite side is connected to a liquid supply pipe 743. The liquid supply pipe 743 is connected to an ionization liquid supply device 705.
The ionization liquid supply device 705 includes a liquid storing portion 732 and a liquid feeding pump 731. The ionization liquid stored in the liquid storing portion 732 is supplied to the base part of the emission tube 703 through the liquid supply pipe 743 by the liquid feeding pump 731, passes a thin tube in the emission tube 703, and is emitted to the outside of the emission tube 703 from an emission opening 735 at the distal end of the emission tube 703. The emission tube 703 is surrounded by an outer cylinder 707. When carrier gas (here, nitrogen gas) is supplied from a carrier gas source 708 to the inside of the outer cylinder 707, the gas is released from a distal end opening 736 of the outer cylinder 707.
The emission opening 735 is disposed between the distal end opening 736 of the outer cylinder and the small hole of the extracting electrode 721. Around the emission opening 735, there is formed a flow of the carrier gas from an upstream side as the base side of the emission tube 703 to a downstream side on which the extracting electrode 721 is located with the small hole.
An extraction power supply 728 is disposed outside the vacuum chamber 710.
In a state where the carrier gas supplied from the carrier gas source 708 is released from the distal end opening 736, the liquid feeding pump 731 supplies the ionization liquid to the emission opening 735, the extraction power supply 728 applies a voltage between the emission tube 703 (made of a metal here) and the extracting electrode 721 so that an electric field thereof extracts droplet cluster ions charged with a positive charge from the ionization liquid positioned in the emission opening 735. Then, the cluster ions pass through the small hole of the extracting electrode 721 and enter the inside of the vacuum chamber 710.
On the downstream side of the extracting electrode 721, there are disposed accelerating electrodes 722 and 723 with small holes and transport lens electrodes 724 and 725. When voltages are applied to the electrodes 722 to 725, the droplet cluster ions entering the inside of the vacuum chamber 710 pass through holes formed in the electrodes 722 to 725 so as to be a droplet cluster ion beam, and further propagates toward the downstream side.
A size of an initial droplet cluster ion generated in the atmosphere is approximately 100 nm in diameter. However, the droplet cluster ion generated in the atmosphere is downsized due to Rayleigh fission that occurs when Coulomb repulsion of itself exceeds surface tension of the droplet. Further, the droplet cluster ions inevitably collide with gas molecules in the atmosphere so that many ions are scattered. Therefore, only a small amount of the droplet cluster ions can enter the inside of the vacuum chamber 710, and the size of the droplet cluster ion is decreased to be smaller than that of initially generated one.
In addition, for use as the droplet cluster ion beam, it is necessary to apply a positive high voltage with respect to the ground potential to the emission tube 703 as the generation source. Further, it is also necessary to apply high voltages to the extracting electrode 721, the first accelerating electrode 722, and the transport lens electrode 724 disposed in the low vacuum environments in the vacuum chamber 710. Therefore, an arcing phenomenon is apt to occur in the vacuum chamber 710, and hence it is difficult to obtain the droplet cluster ion beam.
In addition, it is necessary to separate the atmosphere outside the vacuum chamber 710 from the inside space of the vacuum chamber 710, both of which are connected to each other through the small hole of the extracting electrode 721. Therefore, the first and second vacuum evacuating devices 729a and 729b for evacuating the inside space of the vacuum chamber 710 are required to be large ones; and hence, difficulty arises when they are used in that they occupy large areas and in terms of cost.
Consequently, in the ion source on the conventional technology, disposing the emission opening of the emission tube in the atmosphere so that the droplet cluster ion beam is generated in the atmosphere provides small amount of the droplet cluster ions that can be actually used. Hence, the conventional technology is of little practical use.


Hydraulic pumps compress and move hydraulic fluids by mechanical action in order to generate and transmit power. In hydraulic tool systems, hydraulic pumps provide high-pressure fluid to various actuators that transmit forces necessary to perform work. The actuators of such hydraulic tool systems often require that hydraulic fluid be provided at different flow rates and pressures for proper function. Variable displacement pumps can be utilized to accommodate the varied flow rate and pressure requirements, both individually and collectively, of the multiple actuators of hydraulic tool systems.
Swashplate-type axial piston pumps are variable displacement pumps commonly used in hydraulic tool systems. Swashplate-type axial piston pumps include a plurality of plungers having one end held against an engagement surface of a tiltable swashplate. A ball-and-socket slipper joint is provided at the interface between each plunger end and the engagement surface of the swashplate to allow for relative sliding and pivoting motion. Each plunger reciprocates within an associated cylinder as the plungers rotate relative to the tilted engagement surface of the swashplate. When a plunger is retracted from an associated cylinder, low-pressure fluid is drawn into that chamber. When the plunger is forced back into the cylinder by the engagement surface of the swashplate, the plunger pushes fluid from the cylinder at an elevated pressure.
Each cylinder and associated plunger together at least partially form a pumping chamber configured to intake hydraulic fluid from an inlet passage and to discharge hydraulic fluid into an outlet passage. Each pumping chamber interfaces with the inlet passage and the outlet passage through a port plate. The port plate includes an inlet port through which hydraulic fluid is drawn from the inlet passage into the pumping chamber and an outlet port through which hydraulic fluid is expelled from the pumping chamber into the outlet passage. As a plunger of a pumping chamber moves from a top-dead-center (TDC) position at the end of a discharge stroke to a bottom-dead-center position at the end of an intake stroke, the plunger passes the inlet port as it rotates relative to the port plate. As a plunger of a pumping chamber moves from a bottom-dead-center (BDC) position at the end of an intake stroke to a top-dead-center position at the end of a discharge stroke, the plunger passes the outlet port as it rotates relative to the port plate.
The tilt angle of the swashplate is directly related to an amount of fluid pushed from each cylinder during a single relative rotation between the plungers and the swashplate. Similarly, based on a restriction of a fluid circuit connected to the pump, the amount of fluid pushed from the cylinder during each rotation is directly related to the flow rate and pressure of fluid exiting the pump. Accordingly, a higher swashplate tilt angle of a pump equates to a greater flow rate and/or pressure of the pump, while a lower swashplate tilt angle results in a lower flow rate and/or pressure. Likewise, a higher swashplate tilt angle requires more power to produce the higher flow rates and pressures than does a lower swashplate tilt angle. As such, when the demand for fluid from the hydraulic tool system is low, the swashplate angle is typically reduced to lower the power consumption of the pump.


(1) Field of the Invention
The invention relates to an inflatable packing device including a sophisticated elastomeric inflatable bladder, either alone or in combination with a sophisticated cover.
(2) Definition of Terms
As used herein and in the claims, the phrase "inflation initiation" refers to the location or point on the exterior of the device where first flexing of the contour of the device resulting from effective inflation is expected to occur. Inflation initiation can occur at a plurality of locations or points, depending upon choice of design.
As used herein and in the claims, the phrase "inflation element" means: the sub-assembly generally composed of the bladder, ribs, cover, upper securing means and lower collars or securing means.
As used herein and in the claims, the phrase "point of contact" means: the initial and subsequently latest expected location of interface between the exterior of the device and the wall of the well during effective inflation.
As used herein and in the claims, the phrase "effective inflation" means: the quantum of expansion of the bladder during the setting of the packing device from the run-in position of the apparatus to from between no more than about 70% to no more than about 85%, by volume, of the interior of the bladder when fully set in the well bore.
As used herein and in the claims, the phrase "departure angle" means: the angle between a straight line parallel to the longitudinal axis of the well and along the inside diameter wall of the well passing through a point of contact and a straight line drawn tangent to the exterior surface of the device for an interval of length extending from the point of contact to a distance of about one run-in diameter, this line too passing through the same point of contact. The longitudinal axis of the borehole and the two lines defining the departure angle must all be coplanar.
As used herein and in the claims, the phrase "expansion profiles" means: the transitional forms taken by the flexible portion of the inflation element during effective inflation.
As used herein, the phrase "uniform inflation profiles" means: the circumstance when the "expansion profiles" taken by the inflation element closely approximate straight line profiles from the point of contact to the end of the collar.
As used herein, the phrase "expansion ratio" means: the ratio of the diameter of the fully set inflation element, divided by the run-in diameter of the inflation element.
(3) Description of the Prior Art
Inflatable packers, bridge plugs, and the like, have long been utilized in subterranean wells. Such inflatable tools normally comprise an inflatable elastomeric bladder element concentrically disposed around a central body portion, such as a tube or mandrel. A sheath of reinforcing slats or ribs is typically provided exteriorally around the bladder with an elastomeric packing cover concentrically disposed around at least a portion of the sheath. Generally, a medial portion of the sheath will be exposed and without a cover for providing anchoring engagement of the packer to the wall of the well. Pressured fluid is communicated from the top of the well or interior of the well bore by means of a down hole pump to the interior of the body and thence through radial passages provided for such purpose or otherwise around the exterior of the body to the interior of the bladder during inflation.
Normally, an upper securing means engages the upper end of the inflatable elastomeric bladder and the reinforcing sheath (if included in the design), sealably securing the upper end of the bladder relative to the body, while a lower collar or securing means engages the lower end of the bladder and reinforcing sheath, securing the lower end of the bladder for slidable and sealable movement relative to the exterior of the body, in response to inflation forces. The elastomeric cover may be secured to the exterior of the sheath or placed around the exterior of the bladder, in known fashion.
With inflatable packers of this type, it has been observed that the portion of the bladder adjacent the exposed sheath section of the packer prematurely inflates prior to the other portions of the bladder which are reinforced against expansion by the reinforcing sheath and/or the elastomeric packing cover element. When the inflation element expands, one end of the bladder moves toward the other end of the device, and the bladder area adjacent the exposed sheath inflates until it meets the wall of the well bore, which may be cased or uncased. If the well bore is uncased, the well bore will have an earthen wall, and if the well bore is cased, the wall of the well bore will be the internal diameter surface of the casing.
It has been noted in a number of prior art designs that when service conditions encompass moderate expansion ratios, a propensity for the bladder to pinch around the exterior of the body arises, creating either a seal or a convoluted fold in the bladder that sometimes prevents the effective communication of further fluid throughout the bladder and preventing contiguous inflation propagation. The pinching seal and/or fold(s) can become entrenched in the bladder whereupon they obstruct further passage of fluid employed for inflating the bladder and therein keep fluid from reaching the farthest portions of bladder to be inflated. When this occurs in service, it always results in a soft set condition and in the imminent loss of seal between the cover and wellbore. This problem is discussed in detail in Eslinger, et al. "Design and Testing of a High-Performance Inflatable Packer," SPE 37483, Society of Petroleum Engineers (1997). Tools designed to control inflation shape problems are discussed in the Eslinger paper are described in detail in U.S. Pat. No. 5,605,195 issued Feb. 25, 1997, and entitled "Inflation Shape Control System For Inflatable Packers," and in U.S. Pat. No. 5,507,341 issued Apr. 16, 1996, and entitled "Inflatable Packer With Bladder Shape Control."
Folds in the bladder can be expected to occur in prior art devices like that shown in FIG. 18 when the expansion ratio is greater than 2:1. Designs of this sort inherently experience large departure angles and unfavorable expansion profiles when the expansion ratio is about 2:1 or more. By utilization of the design of the present invention, the departure angle is preferably controlled at no more than about 15.degree. and the inflation element experiences a uniform inflation profile and therefore, no folds or pinches will occur even if the expansion ratio is 3:1, or even higher. Elimination of the propensity to form folds and pinches in the present invention can be attributed to exceptionally low departure angles throughout inflation and the propagation of uniform inflation profiles throughout effective inflation.
The formation of folds creates unusually high triaxial stresses and strains in the vicinity of the fold. Correspondingly, these triaxial stresses and strains create a condition that causes localized failure of the bladder by means of cracking and/or tearing. Failure occurs because the physical properties of the elastomeric material composing the bladder are not adequate to survive the localized triaxial stresses and strains.
Except for the devices described in my patents U.S. Pat. No. 5,469,919, U.S. Pat. No. 5,564,504 and U.S. Pat. No. 5,813,459, all other prior art devices having an element construction similar to that shown in FIG. 18 experience large departure angles and unfavorable expansion profiles when the expansion ratio is greater that 2.00:1, i.e., departure angles greater than 25.degree. at a 2:1 expansion ratio and expansion profiles similar to that shown in FIG. 18. An expansion profile would be deemed unfavorable if the slope of the exterior surface at any point on the inflation element exceeds 15.degree. relative to the longitudinal axis of the wellbore. The term "unfavorable expansion profile" is only applicable to the "effective inflation" portion of the inflation cycle. The propensity to form pinching seals and folds is directly related to undesirable combinations of expansion ratio, departure angles and expansion profiles of the device. In prior art devices, pinching seals and folds are experienced upon the combination of departure angles greater than about 15.degree. and an expansion ratio greater than about 2.35:1.
With regard to covers, at expansion ratios of 2:1 and more, the departure angle in prior art devices other than those for the preferred embodiments in my aforementioned patents will be greater than 20.degree. and the combination of a departure angle greater than 20.degree. and an expansion ratio greater than about 2:1 has been observed to result in cracking and tearing in covers. Once a tear or tears occur, non-uniform rib spacing results. Non-uniform load distribution within the cover also occurs and general discontinuity of the cover results. These conditions, in turn, can result in extrusion of the bladder between ribs resulting in subsequent failure of the bladder and service failure of the device.
In my U.S. Pat. Nos. 5,469,919, and 5,564,504, and 5,813,459 entitled "Programmed Shaped Inflatable Packer Device," issued Sep. 29, 1998, I disclose methods to abate the formation of pinching seals and folds during inflation of prior art devices by using a design which includes a series of shaped-controlling means on an elastomeric packing cover along the length of the bladder in the form of high and low modulus modules of varying lengths and thicknesses. While this design is an advancement in the art, the design of the modules leaves comparatively sharp angled transitional chamfers and significant size Differences between the high and low modules. These chamfers and different diameters are of such magnitude that they are easily detected by the naked eye. The short transitional chamfers give rise to localized stresses and strains in expanded covers. These localized stresses and strains can cause cracking and/or tearing in the covers which can ultimately result in device failure.
In another prior art device which was subjected to service conditions having expansion ratios of 2.35:1 and 3:1, the minimum achievable departure angles were about 15.degree. and 23.degree., respectively. This device used a plateau cover interval concept in accordance with my patents U.S. Pat. No. 5,469,919, U.S. Pat. No. 5,564,504 and U.S. Pat. No. 5,813,459 and has been made commercially available by High Pressure Integrity, Inc. under the product name "Z-44". While this product was an advancement and improvement over other prior art devices, the variations of constant thickness cover intervals with abrupt and relatively short transitions from one thickness to another caused comparatively high localized stress and strain concentrators in the cover which occasionally resulted in cracking and tearing of the cover. Z-44 and similar devices always exhibited rib kinking and experienced occasional rib cutting of the bladder. Additionally, inflation profiles exhibited plateau intervals (intervals of constant diameter along the length of the device) rather than relatively straight sloped profiles in the interval between the last point of contact with the casing (POC) and the end of the collar. Additionally, the plateau cover interval concept abated the formation of pinches and folds in bladders at moderate expansion ratios, but did not eliminate their occurrence at expansion ratios greater than 2.35:1.
The ability to successfully deflate and retrieve an inflatable device is a common service requirement. A pinch or fold might still have formed in a bladder during inflation even though the inflation element effected a satisfactory seal against the wall of the well. During deflation, a fold can pinch and seal around the body, obstructing the transmission of fluid out of the lower portions of the bladder and thereby prevent complete deflation of the bladder. Once a fold is formed, it is permanently entrenched in the bladder and results in multiple layers of bladder beneath the ribs. These layers in turn result in a deflated diameter which is greater than the initial run-in diameter of the inflation element. Retrieval of the device to the earth's surface is thus compromised since the device might not be able to pass through restrictions in the well bore as it is moved upwardly therein.
I have now discovered that the problems described above can be further abated by providing an inflatable packing device having a combination of an excellent uniform expansion profile during effective inflation and minimal departure angles throughout the inflation cycle.
The invention permits orchestration of varying sophisticated contours and configurations in the bladder or in a combination of the bladder and the cover to provide a uniform expansion profile in an expected, i.e., pre-determinable, manner which can be achieved with only minimal or nominal experimentation which will be within the ordinary skills of those knowledgeable in the design and use of inflatable elastomeric devices for use in subterranean wells, and by adhering to the teachings herein.


This invention relates to an improved method of preparing high purity polyamic acids, to be transformed into polyimide resins which, in turn, are used in the processing of circuitry in the microelectronics industry. The improvement relates to increased yield.
Due in part to such characteristics as high tensile properties, desirable electric properties and excellent stability in the face of heat and water, polyimide resins have been widely used in the processing of microelectronic circuitry. However, the electrical properties of microelectronic circuits can be impaired by the presence of ionic impurities, hence it is vital that polyamic acids and polyimides prepared from them, be ionically "pure". The necessity of using polyamic acids with reduced ionic impurities, when working in the electronics field, is well-recognized. For example, see U.S. Pat. No. 4,225,702, issued Sept. 30, 1980, to Mikino et al.
Mikino et al. disclose a method of preparing a polyamic acid with reduced ionic impurities. It involves reacting a diamine or diaminoamide compound monomer with a polycarboxylic acid dianhydride monomer, wherein said monomer compounds have been purified by a recrystallization process so that they have reduced ionic impurities.
While recrystallization is an acceptable method of reducing impurities, it has the disadvantage of yielding purified monomers in an amount equivalent to only about 80 to 85% by weight of the unpurified monomer.
The present invention provides an improved method of preparing high purity polyamic acids that provides an increased yield of the purified monomers.


This invention is directed to disposable swimpants and swimsuits for incontinent adults and children. More particularly, the swimpants include a material which is permeable to fluid, but substantially impermeable to larger bowel movement material.
For example, disposable swimpants and swimsuits for pre-toilet trained children usually have absorbent cores and moisture barriers to prevent leaks of urine and bowel movements. When a child swims while wearing a disposable swimpant, water gets inside the swimpant. One potential problem is that if bowel movement material is also inside the swimpant, when the child leaves the water, or stands up above the surface of the water, water will exit the swimpant through the leg openings and/or the waist opening and the bowel movement material may also exit along with the water, thus creating a sanitation problem. Even if the disposable swimpant has containment flaps, the bowel movement material could conceivably exit the swimpant along with the water through the leg openings and/or waist opening.
Another possible problem is that sand may end up within the swimpants and swimsuits of children at the beach. The sand can be an irritant to the skin and uncomfortable to the wearer. However, currently available disposable swimwear is not designed to allow sand to move away from direct contact with the wearer's skin.
There is a need or desire for a swimwear garment that provides bowel movement containment before and after swimming and also allows sand to move away from direct contact with the wearer's skin.


1. Technical Field
Embodiments of the present invention relate to a projector and a keystone distortion correction method for a projector.
2. Related Art
In a projector, the tilt of the chassis in the installation condition causes a keystone distortion in the projected image. Although such a keystone distortion has been corrected by the user with button operations, automated correction methods have gradually been adopted in recent years.
For example, there has been known a method of installing a range sensor for measuring the distance between the projector and the screen in the projector, detecting the tilt angle of the projector with respect to the screen based on an output of the range sensor, and correcting the keystone distortion in accordance with the tilt angle (see, e.g., JP-A-2000-122617).
Further, there has also been known a method of providing an acceleration sensor inside the projector to detect the tilt of the projector, and thus performing the keystone distortion correction of the projection image (see, e.g., JP-A-2003-283963).
However, according to these methods, an expensive component such as a range sensor or an acceleration sensor needs to be incorporated therein, and a problem of increase in cost arises. Therefore, particularly in projectors, it is difficult for low price popularization models to incorporate it from a viewpoint of cost, and accordingly, a problem arises that the automated keystone distortion correction function (auto keystone function) can hardly be implemented in popularization models.


Siphons supplying carbonated water (soda) use dispenser valve heads which, normally, comprise a valve body crossed by a circulation channel. This channel, at one end, ends in a dispenser outer spout, while at the other ends into a dip tube located inside the bottle.
In general, the valve body is formed by the head walls, therefore this kind of head has a large volume and require a large mass of material for its manufacture.
Further, in order to allow dispensing of the liquid contained into the bottle, a check valve is included into this circulation channel, which is actuated by means of a rigid lever projecting outwardly from the valve head. Therefore, this kind of rigid lever is the means used typically by conventional valve heads.
On the other hand, by means of the improvements of the instant invention, a head is obtained the valve body of which is covered by a covering hood having a diametrical slot, constituting an operating channel for command thereof. The latter, being intended to hold a check valve, has its fulcrum in said covering hood and comprises an articulated arm which is foldable over the covering hood, wherein folding stops and a folding straps are located for retaining the end of the arm which partially closes said diametrical slot.
This constitution of the head affords a better operation and requires a smaller mass of constituting material, which makes the head lighter and less expensive. In fact, the valve body does not act as a support for the command means, therefore, the latter is reduced to its minimum possible expression. This simplification of the valve body is compensated by the presence of a covering hood protecting it from shocks and dirt.
Further, the instant covering hood is designed for serving as mounting means for a command means the articulated arm of which is foldable on said hood, where it has folding stops and a strap retaining its end. The inclusion of a diametrical slot allows fixing the strap and unfolding the articulated arm.
The smaller base of the hood and the cited stops prevent the folding articulated arm from being pressed in by any accidental pressure, in which case the valve stem would be displaced and an undesirable delivery of liquid would take place. Therefore, frequent shocks and pressures produced during storage and loading and unloading of trucks may not actuate the command means which is folded inside the diametrical slot and also properly strapped.
The perfect compatibility between the forming elements is demonstrated by the engagement between the valve body and the covering hood, since they not only have connecting means therebetween, but, further, the hood has a side mouth. This mouth, originated at the edge of the open larger base, allows the passage of the outer spout through which the carbonated liquid is delivered.


The present invention concerns a model of the acoustic sound channel associated with the human phonation system and/or music instruments and which has been realized by means of an electrical filter system.
Furthermore, the invention concerns new types of applications of models according to the invention, and a speech synthesizer applying models according to the invention.
The invention also concerns a filter circuit for the modelling of an acoustic sound channel.
In its most typical form, this invention is associated with speech synthesis and with the artificial producing of speech by electronic methods.
One object of the invention is to create a new model for modelling e.g. the acoustic characteristics of the human speech mechanism, or the producing of speech. Models produced by the method may also be used in speech recognition, in estimating the parameters of a genuine speech signal and in so-called Vocoder apparatus, in which speech messages are transferred with the aid of speech signal analysis and synthesis with a minor amount of information e.g. over a low information rate channel, at the same time endeavouring to maintain the highest possible level of speech quality and intelligibility.
Since the model of the invention is intended to be suitable for the modelling of events taking place in an acoustic tube in general, the invention is also applicable to electronic music synthesizers.
The methods of prior art serving the artificial producing of speech are divisible into two main groups. By the methods of the first group only such speech messages can be produced which have at some earlier time been analyzed, encoded and recorded from corresponding genuine speech productions. Best known among these procedures are PCM (Pulse Code Modulation), DPCM (Differential Pulse Code Modulation), DM (Delta Modulation) and ADPCM (Adaptive Differential Pulse Code Modulation). A feature common to these methods of prior art is that they are closely associated with signal theory and with the general signal processing methods worked out on its basis and therefore imply no detailed knowledge of the character or mode of generation of the speech signal.
The second group consists of those methods of prior art in which no genuine speech signal has been recorded, neither as such or in coded form, instead of which the speech is generated by the aid of apparatus modelling the functions of the human speech mechanism. First, from genuine speech are analyzed its recurrent and comparatively invariant elements, phonetic units or phonemes and variants thereof, or phoneme variants, in varying phonetic environments. In the speech synthesizing step, the electronic counterpart of the human speech system, which is referred to as a terminal analog, is so controlled that phonemes and combinations of phonemes equivalent to genuine speech can be formed. To date, these are the only methods by which it has been possible to produce synthetic speech from unrestricted text.
In the territory between the said two groups of methods of prior art is located Linear Predictive Coding, LPC, /1/ J. D. Markel, A. H. Gray Jr.: Linear Prediction of Speech, New York, Springer-Verlag 1976. Differing from other coding methods, this procedure necessitates utilization of a model of speech producing. The starting assumption in linear prediction is that the speech signal is produced by a linear system, to its input being supplied a regular succession of pulses for sonant and a random succession of pulses for unvoiced speech sounds. It is usual to employ as transfer function to be identified, an all-pole model (cf. cascade model). With the aid of speech signal analysis, estimates are calculable for the coefficients (a.sub.i) in the denominator polynomial of the transfer function. The higher the degree of this polynomial (which is also the degree of the prediction), the higher is the precision with which the speech signal can be provided with the aid of the coefficient a.sub.i.
The filter coefficients a.sub.i are however nonperspicuous from the phonetic point of view. To realize a digital filter using these coefficients is also problematic, for instance in view of the filter hardware structures and of stability considerations. It is partly owing to these reasons that one has begun in linear predicting to use a lattice filter having a corresponding transfer function but provided with a different inner structure and using coefficients of different type.
In a lattice filter of prior art, bidirectionally acting and structurally identical elements are connected in cascade. With certain preconditions, this filter type can be made to correspond to the transfer line model of a sound channel composed of homogeneous tubes with equal length. The filter coefficients b.sub.i will then correspond to the coefficients of reflection (.vertline.b.sub.i .vertline.<1). The coefficients b.sub.i are determinable from the speech signal by means of the so-called PARCOR (Partial Correlation) method. Even though the coefficients of reflection b.sub.i are more closely associated with speech production, i.e., with the articulatory aspect, generation of these coefficients by regular synthesis principles has also turned out to be difficult.
It is thus understood that speech synthesis apparatus of the terminal analog type, known in prior art, implies that speech production is modelled starting out from an acoustic-phonetic basis. For the acoustic phonation system, consisting of larynx, pharynx and oral and nasal cavities, an electronic counterpart has to be found of which the transfer function conforms to the transfer function of the acoustic system in all and any enunciating situations. Such a time-variant filter is referred to as a terminal analog because its overall transfer function from input to output, or between the terminals, aims at analogy with the corresponding acoustic transfer function of the human phonation system. The central component of the terminal analog is called the sound channel model. As known, this is in use e.g. in vowel sounds and partly also when synthesizing other sounds, depending on the type of model that is being used.
Since the human phonation system is extremely complex of its acoustical properties, a number of simplifications and approximations must be made when formulating models for practical applications. A problem of principle which figures centrally in such model formulation is that the sound channel is a subdivided system with an acoustic transfer function composed of transcendental functions. Creation of a corresponding terminal analog arrangement using lumped electrical components requires that the acoustic transfer function can be approximated with the aid of rational, meromorphic functions.
Another centrally important point is the controllability of the model, that is the number and type of control parameters required in the model to the purpose of creating speech, and the degree in which the group of control parameters meets the requirements of optimal, "orthogonal" and phonetically clear-cut selection.
As known in the prior art, in constructing sound channel models, the acoustic sound channel is simplified by assuming it to be a straight homogeneous tube, and for this the transfer line equations are calculated (cf. /2/ G. Fant: Acoustic Theory of Speech Production, the Hague, Mouton 1970, Chapters 1.2 and 1.3; and /3/ J. L. Flanagan: Speech Analysis Synthesis and Perception, Berlin, Springer-Verlag 1972, p. 214-228). The assumption is made that the tube has low losses and is closed at one end; the glottis, or the opening between the vocal cords, closed; and the other end opening into the free field. The acoustic load at the mouth opening may be simply modelled either by a short circuit or by a finite impedance Z.sub.r. The acoustic transfer function that is being approximated will then have the form: ##EQU2## where
y (s)=.alpha.+j.beta.=propagation coefficient
.alpha.=attenuation factor
.beta.=.omega./c=phase factor
.omega.=angular frequency
c=velocity of sound
Z.sub.r =radiation load impedance
Z.sub.o =characteristic impedance of the channel
l=length of the channel.
Assuming that the losses of the channel are minor and that the channel terminates in short circuit (Z.sub.r =0), or that the channel is lossless and Z.sub.r is resistive, Equation (1) becomes: ##EQU3## where A, a and k are real. The logarithmic amplitude graph of the absolute value of the transfer function H.sub.A (.omega.) is shown in FIG. 7. The homogeneous sound channel chosen as starting point for the approximation is most nearly equivalent to the situation encountered when pronouncing a neutral vowel (.omega.). The profile of the sound channel and its transfer function are altered for other vowel sounds.


In various communication systems, digital-to-analog converters are used to convert digital signals to analog signals before transmission. Digital-to-analog converters may introduce quantization noise into the analog signals—particularly when a large number of signal levels are used. Examples of techniques that utilize a large number of output levels include Tomlinson-Harashima-Precode and advance modulation schemes such as OFDM and discreet multi-tone modulation.
Typically, to reduce the effect of quantization noise on system performance, a power spectrum density (PSD) level of the quantization noise should be below a predetermined PSD level of unavoidable noises. A typical requirement is for the quantization noise to have a PSD that is 10 decibels below the PSD of unavoidable noises. Examples of unavoidable noises include additive white Gaussian noise (AWGN), alien cross-talk from other cables or transmitters and quantization noise of the analog to digital converter at the receiver.
Conventional digital-to-analog converter designs produce a quantization noise with a white PSD evenly distributed among all frequency components. However, the communication system performance is often limited by a worst case channel. The frequency response of this channel varies significantly within the transmission bandwidth. As a result, the quantization noise from the transmitter digital-to-analog converter may be shaped by the channel and observed by the receiver.
The peak of the quantization noise PSD (shaped by the channel) observed by the receiver must be lower than other noises by a predetermined level. As a result, a large number of bits may be required for the digital-to-analog converter input and the digital-to-analog converter size and complexity are increased. Reducing the size and complexity of a digital-to-analog converter would lower the overall cost of the system.
Referring now to FIG. 1, a transmitter 8 having an input 10 from an advance modulation scheme or a pre-coding scheme is illustrated. The input 10 generates an N-bit digital input to a truncation module 12. The truncation module 12 truncates the N-bit signal to an M-bit signal, where M is an integer less than N. The truncation module 12 eliminates the least significant bits from the N-bit digital input signal. The M-bit signal is provided to a digital-to-analog converter 14 where it is converted to an analog output signal corresponding to the M-bit signal.
Referring now to FIG. 2, a signal model illustrating the input signal an, which corresponds to the output of the truncation module 12, is summed with truncation noise qn at a summing module 16. The truncation noise qn is inherent in the truncation module 12. The truncation noise is sometimes referred to as quantization noise.
Referring now to FIG. 3, a 10GBASE-T transmitter 20 having a pre-coder 18 is illustrated. An input signal ak is provided to a summing module 22, the addition module 22 generates a summed signal dk as will be described below. The signal dk is provided to a modulo operation module 24 where it is converted to a signal sk that has N-bits. Feedback of the signal sk is provided through a feedback filter 26 having a transfer function P(z). The output of the feedback filter 26 is provided to the addition module 22. Referring back to modulo operation module 24, the N-bit signal, sk is provided to the truncation module 28, which truncates the signal to an M-bit signal that is provided to the digital-to-analog converter 32 conversion to an analog signal. The digital-to-analog converter 32 illustrated in FIG. 3 may be implemented with Tomlinson-Harashima-Precode (THP). The approach illustrated in FIGS. 1-3 has quantization noise problems that degrade the performance of the communication system.


Cardiovascular diseases are a class of diseases that involve the heart or blood vessels. Mendis et al., Global Atlas on Cardiovascular Disease Prevention and Control—World Health Organization, World Heart Federation, and World Stroke Organization 2011. Cardiovascular diseases include coronary artery diseases such as angina and myocardial infarction (commonly known as heart attack), stroke, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, cardiac arrhythmia, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, and venous thrombosis. Id.; Lancet 2014, 385, 117-171. Cardiovascular diseases are the leading cause of death globally. Mendis et al., Global Atlas on Cardiovascular Disease Prevention and Control—World Health Organization, World Heart Federation, and World Stroke Organization 2011. In 2013, cardiovascular diseases resulted in 17.3 million deaths (31.5%), up from 12.3 million (25.8%) in 1990. Lancet 2014, 385, 117-171. In the United States, 11% of people between 20 and 40 have a cardiovascular disease, while 37% between 40 and 60, 71% of people between 60 and 80, and 85% of people over 80 have a cardiovascular disease. Go et al., Circulation 2013, 127, e6-e245.
One form of cardiac arrhythmia is bradycardia, a slow heart rate condition, which can cause fainting, dizziness, malaise, general weakness, excessive fatigue, chest pain, or failing memory. With no approved drug therapy available for effective treatment of chronic bradycardia, a cardiac pacemaker must often be installed into a patient to sustain his/her life. Although several studies had investigated potential therapy with some drugs (Alboni et al., Am. J. Cardiol. 1990, 65, 1037-1039; Ling et al., Ann. Pharmacother. 1998, 32, 837-839; Benditt et al., Am. J. Cardiol. 1983, 52, 1223-229), the adverse side effects at therapeutic doses prevent routine, long-term use of these previously tested drug candidates. Thus, currently, there is no approved drug worldwide for treating bradycardia. The treatment of choice for chronic, symptomatic bradycardia is limited to the implantation of a cardiac pacemaker. It is estimated that the United States and Europe, as well as other advanced countries, have a rate of pacemaker implantation of about 50-60/100,000 people per annum. A worldwide survey published in 2009 indicates that approximately one million pacemaker implantations (approximately 740,000 new implants) were performed in the 61 countries responding to the survey. By 2028, it is estimated that over 700,000 new pacemaker implantations will be done in the US alone. The 10-year prevalence (US 1999-2008) of clinically defined bradycardia (abnormally slow heart rate, RPR (resting pulse rate)<60 beats/min) is 15.2% for male adults and 6.9% for females. US National Health Statistics Reports 2011, 41, 1-16. Since the human pulse rate is inversely associated with age and the aged population is increasing worldwide, there will be a continually increasing number of patients with bradycardia requiring pacemaker implants. Furthermore, due to the adverse side effects and high cost of pacemakers, many bradycardia patients either cannot or elect not to have a pacemaker implanted even when needed from a medical perspective.
As noted, current medical treatment for bradycardia requires a surgical insertion of a cardiac pacemaker. The first use of a buried cardiac pacemaker occurred in Sweden in 1958. Since then, this approach for the treatment of abnormal cardiac rhythms has gradually spread all over the world. In recent years, the quality of pacemakers has improved; and as a result, the use of pacemakers to treat bradycardia has greatly increased. Unfortunately, cardiac pacemakers have some limitations. For example, pacemakers require a surgical procedure for implantation in the human body, and infections requiring device removal do occur with a finite frequency. In addition, pacemakers may not provide a normal physiological heart rate response to exertion or a normal contractile pattern. Because of inadequate or inappropriate heart rate response during exertion, patients may develop significant symptoms related to inadequate cardiac output. In addition, pacing the right ventricle only (as occurs with single or dual chamber pacemakers) may lead to significant left ventricular dysfunction and worsening of heart failure in some patients. Left ventricular failure associated with right ventricular pacing may be ameliorated by implantation of a bi-ventricular pacemaker, but this procedure is time consuming, difficult, and not always possible due to technical issues. As has been recently observed, pacemakers and pacemaker leads may fail and are subject to periodic recalls by sovereign regulatory agencies such as the FDA. Finally, the costs of pacemaker implantation, replacement and follow up are high. Nonetheless, in the absence of a reasonable alternative treatment for bradycardia, doctors and patients usually opt to use a pacemaker when it is necessary. Furthermore, many bradycardia patients delay or forgo the pacemaker surgery due to the potential complications discussed herein and choose to live with bradycardia and the associated potentially fatal medical risks instead. Therefore, there is an unmet need for an effective drug therapy for treating bradycardia.


For a bistable nematic liquid crystal display, state transitions (ON-to-OFF or OFF-to-ON) occur under the influence of appropriately applied dynamic electric fields. See, for example, G. Boyd et al., "Liquid-Crystal Orientational Bistability and Nematic Storage Effects," Appl. Phys. Lett. 36, pp. 556-558 (1980) and J. Cheng et al., "Threshold and Switching Characteristics of a Bistable Nematic Liquid-Crystal Storage Display," Appl. Phys. Lett. 37, pp. 1072-1074 (1981). In particular, vertical electric fields cause orientational director transitions to a predominantly vertical alignment configuration, an ON state, for example, for the liquid crystal molecules. Similarly, horizontal electric fields cause orientational director transitions to a predominantly horizontal alignment configuration, an OFF state, for example, which is topologically distinct from the vertical alignment configuration. See U.S. patent application, Ser. No. 98,976 filed on Nov. 30, 1979, U.S. Pat. No. 4,333,708.
In this bistable nematic liquid crystal medium, the horizontal and vertical electric fields are produced with an array of interdigital electrodes as a matrix addressing arrangement for activating and deactivating individual display cells. Although this type of arrangement can provide low to moderate addressing speeds for a moderate electric field strength, it is incapable, from a practical viewpoint, of providing high speed operation. In addition, interdigital electrodes require both a large number of connections per display cell and complex control circuits to activate particular electrodes for switching.
Interdigital electrodes generate nonhomogeneous electric fields and exhibit two distinct switching thresholds for liquid crystal displays, namely, a longitudinal threshold and a transverse threshold. These thresholds represent minimum electric field strengths necessary for detaching disclinations in the liquid crystal medium from boundary discontinuities in surface alignment or topography. Existence of the two separate thresholds and the creation of nonhomogeneous electric fields substantially impair the effectiveness of interdigital electrodes for high speed matrix addressing purposes in liquid crystal displays.
Homogeneous or uniform vertical electric fields can be generated by an array of orthogonally disposed, continuous uniform strip electrodes as the matrix addressing arrangement. This type of electrode arrangement facilitates transitions from the horizontal state to the vertical state, that is, OFF to ON state transitions. Furthermore, it exhibits a single sharp switching threshold for horizontal to vertical state transitions which is of sufficient magnitude and definition to assure reliable, high speed switching. However, the array of strip electrodes is unsuited for generating the fields necessary for vertical to horizontal state transitions, that is, ON to OFF state transitions.


Lighting systems may be deployed to provide lighting for various environments such as parking lots, roadways, sidewalks, structures, etc. In some of these environments, the illumination from the fixtures may be managed by photocontrols that adjust the amount of light produced based upon the amount of ambient light detected by the photocontrol. For example, a photocontrol placed outside may switch off light output from the light fixture during daylight hours and switch on the light output during the evening.
However, changing the programming of these photocontrols to, for example, disable light output or temporarily switch on the light, may be a complicated task. To accomplish the task, a user often needs to have physical access to the photocontrol, which may be installed in a location that is difficult to access, such as a atop a 40-ft. light pole. The difficulty can be magnified when there are many photocontrols which need to be adjusted.


The present invention relates to intermediate molecular weight shaped polyethylene articles such as polyethylene fibers exhibiting relatively high tenacity, modulus and toughness, and to products made therefrom. The polyethylene article is made by a process which includes the step of stretching a solution of polyethylene dissolved in a solvent at a stretch ratio of at least about 3:1.
Polyethylene fibers, films and tapes are old in the art. An early patent on this subject appeared in 1937 (G.B. No. 472,051). However, until recently, the tensile properties of such products have been generally unremarkable as compared to competitive materials, such as the polyamides and polyethylene terephthalate. Recently, several methods have been discovered for preparing continuous low and intermediate molecular weight polyethylene fibers of moderate tensile properties. Processes for the production of relatively low molecular weight fibers (a maximum weight average molecular weight, Mw, of about 200,000 or less) have been described in U.S. Pat. Nos. 4,276,348 and 4,228,118 to Wu and Black, U.S. Pat. Nos. 3,962,205, 4,254,072, 4,287,149 and 4,415,522 to Ward and Cappaccio, and U.S. Pat. No. 3,048,465 to Jurgeleit. U.S. Pat. No. 4,268,470 to Cappaccio and Ward describes a process for producing intermediate molecular weight polyolefin fibers (minimum molecular weight of about 300,000).
The preparation of high strength, high modulus polyolefin fibers by solution spinning has been described in numerous recent publications and patents. German Off. No. 3,004,699 to Smith et al. (Aug. 21, 1980) describes a process in which polyethylene is first dissolved in a volatile solvent, the solution is spun and cooled to form a gel filament, and, finally, the gel filament is simultaneously stretched and dried to form the desired fiber. U.K. Patent Application No. 2,051,667 to P. Smith and P. J. Lemstra (Jan. 21, 1981) discloses a process in which a solution of a polymer is spun and the filaments are drawn at a stretch ratio which is related to the polymer molecular weight, at a drawing temperature such that at the draw ratio used, the modulus of the filaments is at least 20 GPa (the application notes that to obtain the high modulus values required, drawing must be performed below the melting point of the polyethylene; in general, at most 135.degree. C.). Kalb and Pennings in Polymer Bulletin, Volume 1, pp. 879-80 (1979), J. Mat. Sci., Vol. 15, pp. 2584-90 (1980) and Smook et al. in Polymer Mol., Vol 2, pp. 775-83 (1980) describe a process in which the polyethylene is dissolved in a non-volatile solvent (paraffin oil), the solution is cooled to room temperature to form a gel which is cut into pieces, fed to an extruder and spun into a gel filament, the gel filament being extracted with hexane to remove the parafin oil, vacuum dried and stretched to form the desired fiber.
Most recently, ultra high molecular weight fibers have been disclosed. U.S. Pat. No. 4,413,110 to Kavesh and Prevorsek describes a solution spun fiber of from 500,000 molecular weight to about 8,000,000 molecular weight which exhibits exceptional modulus and tenacity. U.S. Pat. Nos. 4,430,383 and 4,422,993 to Smith and Lemstra also describe a solution spun and drawn fibers having a minimum molecular weight of about 800,000. U.S. Pat. No. 4,436,689 to Smith, Lemstra, Kirschbaum and Pijers describes solution spun filaments of molecular weight greater than 400,000 (and an Mw/Mn<5). In addition, U.S. Pat. No. 4,268,470 to Ward and Cappacio also discloses high molecular weight polyolefin fibers.
In general, the known processes for forming polyethylene and other polyolefin fibers may be observed as belonging in one of two groups: those which describe fibers of low average molecular weight (200,000 or less) and those which describe fibers of high average molecular weight (800,000 or more). Between the two groups, there is a molecular weight range which has not been accessible to the prior art methods for preparing fibers of high tensile properties.
There are advantages to the molecular weight ranges thus far mastered. Lower molecular weight polymers are generally synthesized and processed into fibers more easily and economically than high molecular weight fibers. On the other hand, fibers spun from high molecular weight polymers may possess high tensile properties, low creep, and high melting point. A need exists for fibers and methods which bridge this gap, combining good economy with moderate to high tensile properties. Surprisingly, our process makes it possible to accomplish these results.


For example, a weatherstrip is mounted on an opening edge of a vehicular body side opening section opened or closed by means of a vehicular trunk in order to secure a sealing characteristic. This weatherstrip 30 includes a welt section 32 in a substantially letter U shape in cross section and fitted to a flange 31 mounted on a peripheral edge section of the vehicular body side opening section and a trim lip 34 extended from an outer surface of this welt section 32 and which covers and hides an end edge of vehicular body trim 33. This trim lip 34 causes the end edge of vehicular body trim 33 not to be exposed and an outer appearance quality is improved. Welt section 32 is provided with holding lips 35, 35 extended toward obliquely a summit section from an inner surface of the respective side wall sections mutually connected from the summit section. When these holding lips 35 are elastically contacted on flange 31, welt section 32 is held by flange 31 (for example, refer to a Patent document 1).


1. Field of Our Invention
Our invention relates to apparatus for testing mechanical heart valves, and in particular mechanical heart valves having a rigid annulus and one or more pivoting leaflets mounted therein.
2. Description of Related Art
Various types of heart valve prostheses have been proposed, and many give generally satisfactory operation. One popular design for a heart valve prosthesis includes an annular valve body in which a pair of opposed leaflet occluders are pivotly mounted. The occluders are moveable between a closed, mated position, blocking blood flow in an upstream direction, thereby minimizing regurgitation, and an open position, allowing blood flow in a downstream direction. One such heart valve is described, for example, in U.S. Pat. No. 5,147,390 to Campbell, which patent is assigned to CarboMedics, Inc., the assignee of our invention.
A mechanical heart valve, such as that described in the '390 patent, can be expected to open and close a great number of times during its use. It is desirable to minimize, in so far as possible, the number of failures experienced in the use of a prosthetic heart valve. Testing for function is therefore an important part of prosthetic heart valve development and manufacture. Heart valve function testers are known which open and close the mechanical heart valve in an in vitro environment, mimicking the action of the heart. Fluid is forced past the valve to open the valve. An existing back pressure is then allowed to close the valve when the pulsatile forward pressure is removed.
There is, however, another possibility for defects which can be tested. Minute cracks or other surface defects in pivots of leaflet occluders or in pivot recesses of the valve body are difficult to detect. It is known, however, from the application of fracture mechanics, that cracks below a certain maximum size will not cause failure. Cracks or other surface defects larger than the maximum allowable size can be detected by applying a proof test load to the component. The proof test load should be some multiple of the functional vivo load, to provide a factor of safety associated with the test. The primary purpose of proof testing is to detect components of heart valves with flaws larger than a specific size.


Nitrogen is an important plant nutrient. In addition to phosphorous, potassium, and other nutrients, nitrogen is needed to support the growth and development of plant life. Some plants, such as legumes, through a symbiotic relationship with Rhizobium bacteria, fix elemental nitrogen from the atmosphere and fix this nitrogen into the soil. However, most plants grown to produce human and animal food require the use of nitrogen fertilizer in order to sustain their agricultural production.
The most widely used and agriculturally important high-analysis nitrogen fertilizer is urea, CO(NH2)2. While most of the urea currently produced is used as a fertilizer in its granular form, urea-based fluid fertilizers are also well known. As used herein, the term “fluid fertilizers” encompasses liquid fertilizers, i.e. aqueous solutions of fertilizers, and suspension fertilizers, i.e. fertilizer compositions which in addition to water and water-soluble components also contain insoluble components kept in suspension by a suspending agent, such as clay. Suspension fertilizers are excellent carriers for pesticides and micronutrients.
The most commonly known urea-based liquid fertilizer is an aqueous solution of urea and ammonium nitrate, referred to in the fertilizer trade as UAN solution. These fluid fertilizers are used on a variety of crops, such as corn and wheat. When applied to moist soil, the urea component of the fluid fertilizer becomes a source of ammonia as a result of hydrolysis catalyzed by urease, an enzyme produced by numerous fungi and bacteria. The process is fully disclosed in U.S. Pat. No. 5,364,438, which is hereby incorporated by reference. Unfortunately, the urease-catalyzed hydrolysis often converts the urea to ammonia more quickly than it can be absorbed by the soil, resulting in undesirable ammonia loss to the atmosphere through a process called volatilization.
Urease inhibitors slow down the conversion of urea to ammonia, extending the period of nitrogen release. One urease inhibitor is N-(n-butyl) thiophosphoric triamide (NBPT). When incorporated into a urea-based fertilizer, NBPT reduces the rate at which urea is hydrolyzed to ammonia. This allows the nutrient nitrogen to be available to the soil and plants over a longer period of time. NBPT is widely recognized as an effective urease inhibitor, but NBPT is notoriously difficult to handle, because industrial grade NBPT is a waxy, sticky, heat-sensitive and water-sensitive material. As a result, a solvent system was disclosed in U.S. Pat. No. 5,364,438, that allowed the solution of NBPT to be applied to UAN. However, this solution had stability problems as well as problems in delivering and metering into fluid fertilizer.
U.S. Pat. No. 5,352,265, which is hereby incorporated by reference, discloses a granular fertilizer comprising about 90 to 99% urea, 0.02 to 0.5% NBPT and about 0 to 2.2% DCD. The NBPT is added to molten urea as a concentrated solution in an amide solvent. The DCD is added to the urea melt as a solid. This granular product is made to apply directly to the field crop.
The present invention of a dry flowable additive, is prepared by coating a solid urea-formaldehyde polymer (UFP) with a solution or suspension of NBPT in a liquid solvent, preferably an amide solvent. Optionally, the coated UFP may be blended with solid DCD. Prior to application of the fertilizer to the field crop, the dry flowable additive is blended with a UAN solution or aqueous urea, to form the fluid urea-containing fertilizer composition, or blended with solid or molten urea to form a solid urea-based fertilizer. The present invention provides a fluid or solid fertilizer composition that is easy to handle and stable when stored.


Pyrolytic incineration operates on a starved air principle, and air supplied to the pyrolysis chamber generally constitutes less than half of the stoichiometric air requirement for combustion of the waste. The low air supply rate achieves partial combustion and vaporization of the waste, and results in low gas velocity and turbulence in the pyrolysis chamber which minimizes mechanical entrapment of particulate matter in the waste gases.
The waste gases from the pyrolysis chamber, then pass into the thermal reactor section of the incinerator which is located in the stack. Atmospheric air is drawn into the thermal reactor section to achieve substantially complete combustion of the combustible waste gases in a second zone of combustion.
The normal incinerator is designed for peak thermal capacities, and the peak capacity is rarely attained except when waste material is being charged into the combustion chamber. Consequently, the incinerator is normally operating well below peak capacity.
Certain liquid wastes, such as solvents, paint, lacquer, and the like, have a high BTU content, while other water base liquid wastes have a relatively low BTU content. In addition, the viscosity and solids content of the liquid waste can vary considerably.
In the past, incinerators have been designed to separately burn either solid or liquid waste materials and in some cases, incinerators have been designed with sequential combustion chambers to handle both liquid and solid waste. However, none of the incinerators, as used in the past to handle both solid and liquid waste materials have been programmed to utilize the spare, below-peak capacity of the solid waste incinerator.


Currently, computing devices, particularly those associated with machine learning for autonomous and semi-autonomous vehicles, store three dimensional (3D) models that are used as training data for machine learning. This type of training data is computationally expensive and requires a large amount of storage space. As such, it may be difficult for on-board vehicle processors to effectively utilize the training data.


1. Field of the Invention
The present invention relates to high density memory devices based on phase change memory materials, including chalcogenide based materials and on other programmable resistance materials, and methods for manufacturing such devices.
2. Description of Related Art
Phase change based memory materials, like chalcogenide based materials and similar materials, can be caused to change phase between an amorphous state and a crystalline state by application of electrical current at levels suitable for implementation in integrated circuits. The generally amorphous state is characterized by higher electrical resistivity than the generally crystalline state, which can be readily sensed to indicate data. These properties have generated interest in using programmable resistance material to form nonvolatile memory circuits, which can be read and written with random access.
The change from the amorphous to the crystalline state is generally a lower current operation. The change from crystalline to amorphous, referred to as reset herein, is generally a higher current operation, which includes a short high current density pulse to melt or breakdown the crystalline structure, after which the phase change material cools quickly, quenching the molten phase change material and allowing at least a portion of the phase change material to stabilize in the amorphous state.
The magnitude of the current needed for reset can be reduced by reducing the size of the phase change material element in the cell and/or the contact area between electrodes and the phase change material, so that higher current densities are achieved with small absolute current values through the phase change material.
One approach to reducing the size of the phase change element in a memory cell is to form small phase change elements by etching a layer of phase change material. However, reducing the size of the phase change element by etching can result in damage to the phase change material due to non-uniform reactivity with the etchants which can cause the formation of voids, compositional and bonding variations, and the formation of nonvolatile by-products. This damage can result in variations in shape and uniformity of the phase change elements across an array of memory cells, resulting in electrical and mechanical performance issues for the cell.
Additionally, it is desirable to reduce the cross-sectional area or footprint of individual memory cells in an array of memory cells in order to achieve higher density memory devices. However, traditional field effect transistor access devices are horizontal structures having a horizontally oriented gate overlying a horizontally oriented channel region, resulting in the field effect transistors having a relatively large cross-sectional area which limits the density of the array. Attempts at reducing the cross-sectional area of horizontally oriented field effect transistors can result in issues in obtaining the current needed to induce phase change because of the relatively low current drive of field effect transistors.
Thus, memory devices including both vertically and horizontally oriented field effect transistors have been proposed. See, for example, U.S. Pat. No. 7,116,593. However, the integration of both vertically and horizontally oriented field effect transistors can be difficult and increase the complexity of designs and manufacturing processes. Thus, issues that devices having both vertically and horizontally oriented field effect transistors need to address include cost and simplicity of manufacturing.
Although bipolar junction transistors and diodes can provide a larger current drive than field effect transistors, it can be difficult to control the current in the memory cell using a bipolar junction transistor or a diode adequately enough to allow for multi-bit operation. Additionally, the integration of bipolar junction transistors with CMOS periphery circuitry is difficult and may result in highly complex designs and manufacturing processes.
It is therefore desirable to provide both vertically and horizontally oriented field effect transistors on the same substrate that are readily manufactured for use in high-density memory devices, as well as in other devices that may have a need for both types of transistors on one chip. It is also desirable to provide memory devices providing the current necessary to induce phase change, as well as addressing the etching damage problems described above.


1. Field of the Invention
The present invention relates to virtual reality displays.
2. Related Art
Prior methods of virtual reality display systems deployed head or helmet mounted display that placed a viewing screen directly in front of the user's eyes and recorded the movement of the users head to determine what should be shown on the display. Thus, when the head turned to one side, the display was refreshed to show what was in the virtual world in the direction they turned their head.


1. Technical Field
The present invention relates to an improved information-retrieval apparatus. In particular, the present invention relates to an improved digitally-based information-retrieval apparatus. More particularly, the present invention relates to magnetic storage media, such as digital recording tapes. Still more particularly, the present invention relates to magnetic recording heads for writing and reading data to digital recording tapes.
2. Description of the Related Art
Various magnetic recording techniques exist for recording data to and from magnetic storage media, such as magnetic tape. Magnetic tapes are used for data storage in computer systems requiring data removability, low-cost data storage, high data-rate capability, high volumetric efficiency and reusability. The constantly increasing operational speeds of digital computers are creating a demand for corresponding increases in the data storage capacities of magnetic tape recording and reproducing systems, while maintaining the special requirements of high speed digital tape systems.
Tape recording and reproducing systems for use as computer data storage devices are required to provide high data transfer rates and to perform a read check on all written data. To satisfy these requirements, conventional tape systems typically employ methods of recording known as linear recording, in which the tracks of data lie parallel to each other and to the edge of the tape. Linear recording techniques offer high data transfer rates. However, it is desirable to obtain even higher data densities while retaining the advantages of such recording techniques.
Digital linear tape (DLT) is a magnetic linear tape medium that is increasingly being utilized as a medium for data storage. DLT is a magnetic storage medium used to back up data, typically in computer systems. DLT allows for the rapid transfer of data, in comparison to other tape storage technologies. For example, various forms of magnetic read/write heads can be utilized in association with servo mechanisms to read and write data to and from a track of a particular DLT.
Because DLT is currently being utilized as an important tool for data storage, it is desirable to increase the recording density, thus allowing for the faster and more efficient retrieval and writing of data. One method of increasing this storage density involves azimuth recording. The term "azimuth" refers to the horizontal angular distance from a particular reference direction. The use of the word "azimuth" in "azimuth recording" thus suggests a form of angular recording.
Azimuth recording involves the use of a rotating recording head, such that data tracks on a tape may be recorded at different angles with respect to the edge of the tape. Azimuth recording results in a recorded track pattern in which the magnetization directions of adjacent data tracks lie at different azimuth angle to each other. To date, most recording systems have relied strictly on magnetic heads which contain read/write elements but which record only vertically, thus not allowing for angular or "azimuthal" recording of data. One of the principal advantages of azimuth recording over non-azimuth recording is that azimuth recording promotes very high data track packing. Azimuth recording provides much denser track packing than regular track packing spacing because regular track packing spacing typically requires gaps between tracks.
Those systems which do attempt to implement azimuth recording techniques are faced with the challenge of providing fine positioning servo tracking. Servo tracking techniques have been developed to reduce the effects of tracking error and thus improve the data capacity of tape systems. Known servo techniques vary widely, but most involve methods of dynamically moving a read head gap to continually reposition it over a written servo track. The movement of a servo read head gap compensates for lateral tape motion during a read. However, lateral tape motion during writing is not controlled with respect to the write head gap. Thus, the distance between tracks is still limited to the magnitude of the lateral tape motion in order to avoid over-writing previously written tracks.
Based on the foregoing it can be appreciated that a need exists for an improved azimuth recording system which does not encounter problems associated fine positioning servo tracking. A need also exists for an inexpensive and easy to implement apparatus and method which provides fine positioning servo tracking. It is believed that the apparatus and method presented herein solves these problems.


(a) Field of the Invention
The present invention relates to a liquid crystal display and a drive method thereof, in which liquid crystal molecules respond fast even at data voltages of an intermediate grayscale level. More particularly, the present invention relates to a liquid crystal display and a drive method thereof, which improves a liquid crystal response speed with respect to the application of a gate voltage of a twisted nematic liquid crystal display.
(b) Description of the Related Art
A twisted nematic liquid crystal display (TN LCD) has the advantages of enabling control at very thin profile configurations, and of consuming very little power. However, the drawbacks of TN LCDs are that they have slow response speeds with respect to applied voltages, and a limited viewing angle.
FIG. 1 shows a graph of response curves when a voltage is applied to pixels of a TN LCD.
As shown in FIG. 1, a response time of twisted nematic liquid crystals is roughly 15–17 ms from the moment a voltage is applied, and when the applied voltage is switched off, a response time of approximately 20 ms is required. Accordingly, it is difficult to realize images containing a large amount of data.
Various configurations are used to improve response speeds. These include the surface stabilized ferroelectric liquid crystal display (SSFLCD) and the anti-ferroelectric liquid crystal display (AFLCD). However, in these LCDs, alignment and the display of grayscale levels are difficult to obtain, and a high reset voltage is required such that practical applications of the LCDs are not fully feasible.
In more traditional configurations, the slow response speeds make the display of certain images (e.g., moving images) unclear since these images require the display of large amounts of grayscale levels during a short interval of time. Therefore, the TN LCD particularly needs an improvement in response speeds.


Reduced engine operation times in plug-in hybrid electric vehicles (PHEVs) enable fuel economy and reduced fuel emissions benefits. However, the shorter engine operation times can lead to longer refueling intervals ultimately resulting in fuel in a fuel tank of the vehicle becoming old, or sour. Fuel souring may cause acid formation and/or waxing, for example.
One approach to address potential souring of on-board fuel is to force engine on operation to a greater extent, even if not needed. However, the inventors herein have recognized a problem with such an approach. Namely, user satisfaction with the plug-in vehicle may become degraded because the user may be aiming to minimize addition of fuel, and forcing engine operation to utilize stale fuel is directly contrary to the user's goal.
Thus, the inventors herein have devised an approach to at least partially address the issue described above. In one example, a method for a vehicle including an engine and a motor includes displaying a recommended engine fuel fill amount based on a history of actual fuel usage. As an example, the recommended engine fuel fill amount may be determined based on an amount of fuel consumed over a duration, such as since a last fuel refill.
In this way, forced engine operation may be reduced such that user satisfaction may be improved. For example, by determining the amount of fuel consumed since the last fuel refill, an operator of the vehicle may be informed of his/her fuel usage via a display in the vehicle. As such, when the operator refills a fuel tank of the vehicle, the operator may refill the fuel tank with just enough fuel for a selected duration (e.g., three months) such that fuel souring may be prevented. Further, as the operator follows the recommended fuel fill amount, a frequency of forced engine operation (e.g., a fuel maintenance mode) may be reduced, as there is no longer excess fuel that needs to be consumed before souring can occur.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.


Currently available laser delivery techniques used for dermatology, such as for tattoo removal and medical laser ablation, typically operate in the UV, visible, or infrared spectra. Furthermore, current dermatological applications typically involve the propagation of waves using picosecond, nanosecond, microsecond, or millisecond pulse widths, and also involve continuous wave lasers. Often, a fiber optic bundle, articulated mirror system, or the like directs the laser light from a beam source into a hand-piece control unit positioned above the skin and aimed toward the target. This creates an area of free space (i.e., an air gap) between the hand-piece and the target. Because these procedures propagate a laser through free space to illuminate target tissue, they allow for a dangerous degree of electromagnetic energy to be released, both when the wave propagates in free space and when the propagated light reflects off of the target tissue. Under typical circumstances, even a diffuse reflectance of 1% of the transmitted wave into the eyes of an operator or patient is enough to cause permanent ocular damage.
In addition, conventional laser systems exhibit poor heat dissipation at the tissue-air interface. This can exacerbate the negative thermal effects at the tissue surface, which result in potentially drastic changes to the tissue being treated, diminishing overall effectiveness of the treatment, prolonging the time needed to recover between treatments, increasing the number of treatments required, etc. For example, excessive heat can damage or permanently scar the topmost layers of skin, reduce the efficacy of subsequent treatments, and even vaporize water within the tissue. In addition to damaging the target tissue, vaporizing water within the tissue increases the relative fat density at the surface, which causes even more back-scattered light to reflect from the tissue surface during treatment.


1. The Field of the Invention
This invention relates to computerized methods for testing and tracking and, more particularly, to novel systems and methods for testing, tracking, and correcting errors due to software or hardware.
2. Background
Product development cycles have become shorter and shorter. More of the responsibility for testing and “debugging” products falls to the actual beta testers or alpha testers. Nevertheless, products are continuing their development cycle well into their marketing bases.
For example, software is often released for public purchase before the known errors from beta testing have been cured. Hardware is often likewise premature, and more difficult to correct. Alternatively, beta testing may be inadequate, leaving various problems extant within either hardware, software, or a combination thereof.
Purchasers are often left with a need for identification and cure of errors in commercially available software and hardware. In some instances, product manufacturers and suppliers actively solicit comments, improvements, detection and identification of errors, and the like. In other situations, manufacturers and marketers of products are not so forthcoming.
For example, occasionally, problems are comparatively esoteric, and may occur only in a few rare conditions or instances. Nevertheless, some errors occur with sufficient regularity as to seriously encumber users unaware of the existence of such product flaws.
In recent years, computer and software manufacturers have been repeatedly surprised, even amazed, at the groundswell of opposition to products that are not adequately tested, supported, corrected, recalled, or otherwise identified as having correctable flaws.
Software, in particular, has arrived at a new threshold of pain for purchasers and users. Never since the advent of government agencies for consumer protection against fraud, product failure, product inadequacy, manufacturer non-responsiveness, and the like, have so many dollars of product value been subject to such massive amounts of owner and operator time in order to obtain the purported benefits of the products.
Some manufacturers are swift to seek out and post notification of errors existing in their products. Typically, errors are identified, with associated patches for correcting the errors. In some cases, products are recalled. With the advent of the world wide web, a host of users may provide a corresponding host of error corrections, all freely available to users interested in improving the performance or reliability of a purchased software or hardware product in the computer industry.
Historically, a manufacturer or other purveyor of a computer-related product may face a dilemma with respect to certain product flaws. To the extent that an error, built into or programmed into a computer-related product, is comparatively esoteric and unlikely to cause problems for the majority of users, a manufacturer or developer may prefer to ignore it. To the extent that such a flaw or error is ubiquitous and likely to cause pervasive and obvious problems, a manufacturer may prefer to cure the problem. Similarly, to the extent that a problem is likely to cause a comparatively small disruption of promised service, a manufacturer may choose to ignore it. Alternatively, to the extent that a problem is likely to cause serious economic damages to a commercial or industrial user of a software product or physical damage to persons or property as a direct result of the failure of a computer-based product, a manufacturer will take appropriate steps to find a correction to the problem, announce the presence of the flaw and the availability of a corrective measure, and seek to bring all copies of the product into compliance with a corrected version thereof.
Nevertheless, product improvement is largely a matter of motivation. Motivation may arise from personal interest, individual or enterprise-wide frustration, desirability of a result, previous experiences and expectations, and the like. In current process for product improvement, little incentive exists to provide for skilled third parties to improve marketed products. By the same token, manufacturers, whether large or small, may have limited motivation, resources, or the like to locate and correct errors. In fact, a certain motivation may exist to not seek out errors, nor to highlight them, nor even to repair them, in many instances.
What is needed is a mechanism, whereby software and hardware products related to computer systems may be improved profitably by third parties. Likewise, what is needed is an apparatus and method for consistently providing the necessary resources for testing, correction, notification, and product redistribution for products and upgrades related to computer-related based products, whether software or hardware.


1. Field of the Invention
The present invention relates to an image forming apparatus, such as an electronic copying apparatus and a laser printer, and more particularly to an image forming apparatus which has a fixing unit for fixing a developer (e.g., powdered toner) transferred onto a sheet.
2. Description of the Related Art
In recent years, an image forming apparatus (e.g., an electronic copying apparatus and a laser printer) has come to employ the so-called clam shell structure, for easy maintenance and for easy removal of sheets causing an abnormal transfer state. In the clam shell structure, the housing is divided into first and second units (i.e., upper and lower units), with the boundary therebetween defined by a sheet transport path formed inside the apparatus, and wherein the first unit can be opened in a direction away from the second unit.
The image forming apparatus comprises a fixing means for fixing a developer image to a sheet. Normally, the fixing means is of a heating roller type. It includes a pair of fixing rollers (namely, a heating roller and a pressing roller) which are in rolling contact with each other, and a releasing claw which is used for releasing a sheet from the fixing rollers, to prevent the sheet from being wound around the fixing rollers.
Published Unexamined Japanese Patent Application (PUJPA) No. 63-6588 discloses an example of a conventional image forming apparatus which is the clam shell type and which employs a fixing means of the heating roller type. As may be understood from the example in the reference, the releasing claw remains engaged with the fixing rollers even after the first unit is opened or separated from the second unit.
In the conventional image forming apparatus, the releasing claw remains engaged with the fixing rollers even after the first unit is opened, as mentioned above. If the releasing claw is touched by something and is thus subject to an external force, an impact is applied between the releasing claw and the fixing rollers. In such a case, it is likely that the tip end of the releasing claw will be broken or the surfaces of the fixing rollers will be scratched, so that a satisfactory fixing operation or a reliable releasing operation cannot be performed thereafter.


1. Field of the Invention
This invention relates to a process for the preparation of crystalline oxytitanium phthalocyanine. Particularly, it relates to a novel process for the preparation of crystalline oxytitanium phthalocyanine suitable for use in an electrophotographic photoreceptor.
2. Description of the Prior Art
In this field, it is well known that the oxytitanium phthalocyanine may be produced either in a semi-stable .alpha.-crystal phase or in a stable .beta.-crystal phase depending on the production conditions. Further, it is also known that those two crystal phases may be converted from one to another under the influences of physical distortion, organic solvent and/or heat. For example, .alpha.-phase oxytitanium phthalocyanine can be converted into .beta.-phase by heating in an organic solvent such as N-methylpyrrolidone.
On the other hand, Japanese Patent Application Laying Open (KOKAI) No. 63-20365 discloses that crystalline oxytitanium phthalocyanine of which crystal phase can not be classified neither as the .alpha.-phase nor as the .beta.-phase and which shows an intense peak in the X-ray diffraction spectrum at a Bragg angle (2.theta.) of 27.3.degree. can be produced by forming an aqueous suspension of .alpha.-phase oxytitanium phthalocyanine obtained by the acid paste method, adding an aromatic hydrocarbon solvent into the suspension and heating the suspension, and that the obtained phthalocyanine is an useful material particularly as a recording material of an optical disc.
The object of the present invention is to provide a novel and industrially applicable process for the production of oxytitanium phthalocyanine having a crystal phase useful for various purposes such as for use in an electrophotographic photoreceptor.