1. Field of the Invention
An aspect of the present invention relates to a thin film deposition apparatus and a method of manufacturing an organic light emitting device (OLED) by using the same, and more particularly, to a thin film deposition apparatus to form a fine pattern on a large-sized substrate and a method of manufacturing an OLED by using the same.
2. Description of the Related Art
A display device using an organic light emitting device (OLED) has a wide viewing angle, excellent contrast, and rapid response time and thus has recently been highlighted as a next generation display device.
In general, an OLED emits light when holes and electrons respectively injected from an anode and a cathode are recombined in an organic light emitting layer, thereby generating visible light. However, in this structure, it is difficult to obtain high light emission efficiency. Thus, in an OLED, other organic layers such as an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer may be selectively disposed between the anode and the cathode along with the organic light emitting layer.
Moreover, electrodes, the organic light emitting layer, and the organic layer of the OLED may be formed using various methods including deposition. In order to manufacture an organic light emitting display device using deposition, a fine metal mask (FMM) having a pattern of a thin film to be formed is closely adhered to the surface of a substrate on which the thin film is to be formed, and a material for forming the thin film is deposited on the FMM, thereby forming a thin film having a predetermined pattern.
However, it is difficult to form a fine pattern of organic thin films and red, green, and blue luminous efficiency may vary according to the pattern and thickness of the organic thin films. Thus, there are limitations in improving luminous efficiency of an OLED.
In addition, while the size of current display devices is gradually increasing, it is difficult to pattern an organic thin film over a large area by using a conventional thin film deposition apparatus. Thus, it is difficult to manufacture a large-sized OLED having satisfactory driving voltage, current density, brightness, color purity, luminous efficiency, and life span.


This invention relates to high temperature electrochemical converters and specifically to high performance systems employing such devices and methods.
Electrochemical converters perform fuel-to-electricity conversions in a fuel cell (electric generator) mode or electricity-to-fuel conversions in an electrolyzer (fuel synthesizer) mode. The converters are capable of high efficiencies, depending only on the relation between the free energy and enthalpy of the electrochemical reaction, and are not limited by Carnot-cycle considerations.
The key components in an electrochemical energy converter are a series of electrolyte units onto which electrodes are applied and a similar series of interconnectors disposed between the electrolyte units to provide serial electrical connections. Each electrolyte unit is an ionic conductor having low ionic resistance thereby allowing the transport of an ionic species from one electrode-electrolyte interface to the opposite electrode-electrolyte interface under the operating conditions of the converter. Various electrolytes can be used in such converters. For example, zirconia stabilized with such compounds as magnesia, calcia or yttria can satisfy these requirements when operating at an elevated temperature (typically around 1000.degree. C.). The electrolyte material utilizes oxygen ions to carry electrical current. The electrolyte should not be conductive to electrons which can cause a short-circuit of the converter. On the other hand, the interconnector must be a good electronic conductor. The interaction of the reacting gas, electrode and electrolyte occurs at the electrode-electrolyte interface which requires the electrodes be sufficiently porous to admit the reacting gas species and to permit exit of product species.
The approach of forming electrolyte and interconnector components as free-standing plates was disclosed by the present inventor in U.S. Pat. No. 4,490,445, issued Dec. 25, 1984, which is herein incorporated by reference. However, during operation, the stacks of electrolyte and interconnector plates can experience thermal non-equilibrium. Thus, it is important to reduce thermal gradients across the entire converter assembly by facilitating the transfer of heat to and from the electrolyte elements.
When an electrochemical converter performs fuel-to-electricity conversion in a fuel cell mode, waste energy in the form of heat must be removed from the electrolyte surfaces. Conversely, when the converter performs electricity-to fuel conversion in the electrolyzer mode, the electrolyte must be provided with heat to maintain its reaction. In prior systems, heat exchanging has been achieved primarily by the convective heat transfer capabilities of the gaseous reactants as they travel through the assembly. Such reliance on the heat capacity of the reactants creates an inherent thermal gradient in the system, resulting in non-optimum electrochemical processes.
To rectify this problem, the approach of integrating with the electrochemical converter a series of heat transfer elements was disclosed by the present inventor in U.S. Pat. No. 4,853,100, issued Aug. 1, 1989, which is herein incorporated by reference. The above-mentioned integration system facilitates the heat transfer from the fuel cell stacks by reducing thermal gradients across the converter assembly. However, there still exists a need for further improvements in the thermal control mechanisms within electrochemical energy systems. In particular, an improved electrochemical energy conversion system having the ability to more efficiently regulate the operating temperature within the electrochemical assembly would represent a major improvement in the industry.


1. Field of the Invention
The present invention relates generally to a server computer system that provides centralized computing resources to a plurality of users. More particularly, the invention relates to a system and method for maintaining a pool of free virtual machines available to be assigned to users on a server computer.
2. Description of the Related Art
Many commercial businesses and enterprises make extensive use of personal computers (PCs) in their daily operations. Typically, each user of a PC in the enterprise has a networked PC at his/her desk or work area. As the number of networked computer systems utilized in an enterprise increases, the management of resources in the network may become increasingly complex and expensive. Some of the manageability issues involved in maintaining a large number of networked computer systems may include ease of installation and deployment, the topology and physical logistics of the network, asset management, scalability (the cost and effort involved in increasing the number of units), troubleshooting network or unit problems, support costs, software tracking and management, as well as the simple issue of physical space, be it floor space or room on the desktop, as well as security issues regarding physical assets, information protection, software control, and computer virus issues.
Many of these issues may be addressed by centralizing the locations of computing resources. For example, each individual user may connect through a network to a server computer system and use computing resources provided by the server computer system.
Some server computer systems are capable of leveraging the physical hardware resources available by providing virtualization capabilities. Virtualization provides the ability for multiple virtual machines to run together on the same physical server computer. For example, each virtual machine may execute its own operating system and may appear to a user of the virtual machine to be the same as an independent physical computer. The software layer that executes on the physical server computer and manages the various virtual machines is called a hypervisor or virtual machine host software. The hypervisor can run on bare hardware (called a Type 1 or native VM) or under control of an operating system (called a Type 2 or hosted VM).


1. Field of the Invention
The present invention relates to an inkjet recording apparatus which ejects ink droplets to record an image on a recording medium.
2. Description of the Related Art
Japanese Unexamined Patent Publication No. 59597/2005 (Tokukai 2005-59597) discloses an inkjet printer including a conveyance mechanism having a drum which rotates to convey a sheet carried on the outer circumferential surface thereof; a plurality of inkjet heads each having an ejection surface, which are aligned in a conveyance direction of the sheet so that the ejection surface of the each inkjet heads faces the outer circumferential surface of the drum; and a wiper for wiping the ejection surface. In this inkjet printer, all the inkjet heads are fixed on a frame structure. The frame structure is moveable between a printing position and a wiping position. The printing position is a position where the frame structure is disposed when ink droplets are ejected from an ejection surface to a sheet conveyed by the conveyance mechanism. The wiping position is such a position that the ejection surface is disposed farther apart from the outer circumferential surface of the drum, compared to the printing position. At a time of printing, the wiper is in a standby position and faces no ejection surfaces, and the frame structure is positioned in the printing position. At a time of a wiping operation, the frame structure moves to the wiping position. Then, the wiper moves in the circumferential direction of the drum, from the standby position to an opposing position so as to face the ejection surface. Then, the wiper reciprocates in the axial direction of the drum, thereby wiping the ejection surface.


Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple out (MIMO) system.
Some conventional advanced devices include multiple radios for transmitting/receiving using different Radio Access Technologies (RATs). Examples of RATs include, e.g., Universal Mobile Telecommunications System (UMTS), Global System for Mobile Communications (GSM), CDMA2000, WiMAX, WLAN (e.g., WiFi), Bluetooth, LTE, and the like.
An example mobile device is an LTE User Equipment (UE), such as a fourth generation (4G) mobile phone. Such 4G phone may include various radios to provide a variety of functions for the user. For purposes of this example, the 4G phone includes an LTE radio for voice and data, an IEEE 802.11 (WiFi) radio, a Global Positioning System (GPS) radio, and a Bluetooth radio, where two of the above or all four may operate simultaneously. While the different radios provide useful functionalities for the phone, their inclusion in a single device gives rise to coexistence issues. Specifically, operation of one radio may in some cases interfere with operation of another radio through radiative, conductive, resource collision, and/or other interference mechanisms. Coexistence issues include such interference.
This is especially true for the LTE uplink channel, which is adjacent to the Industrial Scientific and Medical (ISM) band and may cause interference therewith It is noted that Bluetooth and some Wireless LAN (WLAN) channels fall within the ISM band. In some instances, a Bluetooth error rate can become unacceptable when LTE is active in some channels of Band 7 or even Band 40 for some Bluetooth channel conditions. Even though there is no significant degradation to LTE, simultaneous operation with Bluetooth can result in disruption in voice services terminating in a Bluetooth headset. Such disruption may be unacceptable to the consumer. A similar issue exists when LTE transmissions interfere with GPS. Currently, there is no mechanism that can solve this issue because LTE by itself does not experience any degradation
With reference specifically to LTE, it is noted that a UE communicates with an evolved NodeB (eNB; e.g., a base station for a wireless communications network) to inform the eNB of interference seen by the UE on the downlink. Furthermore, the eNB may be able to estimate interference at the UE using a downlink error rate. In some instances, the eNB and the UE can cooperate to find a solution that reduces interference at the UE, even interference due to radios within the UE itself. However, in conventional LTE, the interference estimates regarding the downlink may not be adequate to comprehensively address interference.
In one instance, an LTE uplink signal interferes with a Bluetooth signal or wireless local area network (WLAN) signal. However, such interference is not reflected in the downlink measurement reports at the eNB. As a result, unilateral action on the part of the UE (e.g., moving the uplink signal to a different channel) may be thwarted by the eNB, which is not aware of the uplink coexistence issue and seeks to undo the unilateral action. For instance, even if the UE re-establishes the connection on a different frequency channel, the network can still handover the UE back to the original frequency channel that was corrupted by the in-device interference. This is a likely scenario because the desired signal strength on the corrupted channel may sometimes be higher as reflected in the measurement reports of the new channel based on Reference Signal Received Power (RSRP) to the eNB. Hence, a ping-pong effect of being transferred back and forth between the corrupted channel and the desired channel can happen if the eNB uses RSRP reports for handover decisions.
Other unilateral action on the part of the UE, such as simply stopping uplink communications without coordination of the eNB may cause power loop malfunctions at the eNB. Additional issues that exist in conventional LTE include a general lack of ability on the part of the UE to suggest desired configurations as an alternative to configurations that have coexistence issues. For at least these reasons, uplink coexistence issues at the UE may remain unresolved for a long time period, degrading performance and efficiency for other radios of the UE.


1. Field of the Invention
The present invention is directed to a ground contact height sensor for a harvesting header having two pivotally coupled rigid arms.
2. Description of the Prior Art
Agricultural combines may be provided with header height control systems to control the position of the harvesting header relative to the ground. Ground contact sensors may be used to determine the distance of the bottom of the header to the ground. These ground contact sensors generally comprise a downwardly extending arm that contacts the ground below the header. As the arm is deflected upwardly by an obstruction the arm moves a mechanical linkage or a potentiometer which signals the automatic header height control system raising the harvesting header.
In one sensor configuration a J-shaped rigid arm is coupled to a transverse rotatable shaft. As the arm is deflected the shaft is rotated shifting a potentiometer or a mechanical linkage. Because of the J-shape and the rigid nature of the arm it can be difficult to store these arms inside the floor of the header. In addition, these J-shaped arms have a relatively narrow radius, so it can be difficult to put the combine in reverse without damaging the sensor.
In another sensor configuration bowed spring steel hoops form the arms. The hoops can be flattened out to fit within a recess under the floor of the platform. In addition, the hoops form a large radius facilitating reverse movement of the combine. However hoop sensors can be easily damaged during sharp turns if they are following a furrow.
It is an object of the present invention to provide a ground contact height sensor that can be easily stored within a recess under the floor of the header, that will not be easily damaged during sharp turns, and that will not be easily damaged during reverse movements.
The sensor comprises a transverse rotatable shaft, a first rigid arm, a second rigid arm and a connecting member. The rotatable shaft is rotatively mounted to the frame of the header. The first rigid arm has a first end that is rigidly mounted to the rotatable shaft. The first arm extends downwardly and rearwardly from the rotatable shaft in a curved manner. The second rigid arm is pivotally coupled to the second end of the first rigid arm. The second rigid arm extends upwardly and rearwardly from the second end of the first rigid arm. The first and second rigid arms defining a relatively large radius. A connecting member secures the rearmost end of the second rigid arm to the frame of the header. In the illustrated embodiment the connecting member comprises a chain. To maintain the radius of the two pivotally connected rigid arms the hinge joint joining the two rigid arms is provided with a torsion spring. The limits of the pivoting movement is controlled by stops.


This invention relates to a black pigment, a process for making such a pigment and paints and/or plastics containing this pigment.
Heat stable black pigments which contain no carbon have generally been made from materials containing heavy metals and/or other highly toxic materials. Such materials are described, for example, in the Colour Index published in Great Britain and the brochure entitled "Classification and Chemical Descriptions of Mixed Metal Oxide Inorganic Colored Pigments" published by the Dry Color Manufacturers' Association, 1117 North 19th Street, Suite 100, Arlington, Va., 22209. These heavy metal-containing and/or highly toxic materials are, however, undesirable in many applications.


1. Technical Field.
This invention pertains to fluid control systems and particularly to valves. The apparatus of this invention is useful for preventing and correcting the deleterious affects of marine mussels colonizing in marine raw water inlet systems of boats and equipment. The valve apparatus is useful for winterizing these systems where introduction of antifreeze compounds may be desired.
2. Background Information.
Raw water inlet systems, such as those commonly employed in boat engines, marine heads, and marine generators, operate most efficiently when a free and unrestricted flow of water is able to pass through them. The water is used for cooling of engines or machinery, and for flushing of sanitation devices. If the flow of water should become restricted or stopped, the effected equipment may be disabled or damaged.
It has been determined that some marine animals, particularly zebra mussels, dreissena polymorpha, will colonize in the raw water inlets of marine equipment thereby disabling or damaging the equipment. It is therefore economically advantageous to control or eliminate these colonies in boats and marine equipment. The zebra mussel is a small bivalve mollusk which has an elongated thick shell showing alternating light and dark bands. The zebra mussel is found in all of the Great Lakes and is expected to proliferate into other freshwater systems in the Midwestern and Eastern portions of the United States. The zebra mussel is believed to have a substantial negative impact on commercial and recreational boating, including damage to boat cooling and sanitation systems due to constriction of boat plumbing by colonies of the animal. Current zebra mussel control techniques involve scraping or application or chemicals such as hydrogen sulfide, chlorine, ozone, and copper sulfate. It is known that zebra mussels are sensitive to temperatures above 37 degrees C. (98.6.degree. F.), are quickly killed at temperatures between 45.degree.-55.degree. C. (113.degree.-131.degree. F.) and are immediately killed at temperatures above 60.degree. C. (140.degree. F.). This property, sensitivity to heat and chemicals, is utilized by the apparatus and method of the present invention to control zebra mussel infestation.
In addition to the problems associated with zebra mussel infestation in marine plumbing systems, boats and equipment that are laid up in winter due to freezing conditions are subject to damage of their machinery and plumbing systems from internal build up of ice. It is therefore necessary to winterize this equipment by draining and/or the introduction of antifreeze compounds into the raw water systems of the equipment.
In the past, various devices and/or methods have been used or proposed, to either control zebra mussel colonization or permit marine system winterization. However, these devices and methods have significant limitations and shortcomings. And no single apparatus or method is known to have been used for both purposes.
Despite the need in the art for an apparatus and method which overcome the shortcomings and limitations of the prior art, none insofar as is known has been developed or proposed. Accordingly, it is an object of the present invention to provide an apparatus and method of use therefor, which prevents and corrects zebra mussel colonization in marine raw water inlet systems of boats and other equipment. It is also an object of this invention to provide an apparatus and method which is usable to introduce antifreeze and other compounds into the raw water inlet systems of boats and other equipment for winterization purposes. It is an additional object of the invention to provide a combined mussel control and antifreeze introduction system using a single, unitary fittng or set of fittings disposed in the marine equipment. It is a further object of this invention to provide a Zebra mussel control and marine winterization apparatus which is reliable, efficient, economical, and usable by operators and service personnel at marinas and boat yards, as well as owner operators of marine equipment, and which overcomes the limitations and shortcomings of the prior art.


This invention relates to a method and control for defrosting the outdoor coil of a heat pump in a manner which optimizes efficiency and conserves energy.
When a heat pump operates in its heating mode, frost builds up on the pump's outdoor coil. As the frost thickness increases, heat transfer from the outdoor air decreases and the efficiency of the heat pump drops significantly, a substantial amount of energy therefore being wasted. Hence, it is necessary to periodically defrost the outdoor coil. This is usually accomplished by reversing the refrigerant flow in the heat pump which will heat the outdoor coil and melt the frost.
It is recognized that there is an optimum point of frost accumulation at which the heat pump should be switched to its defrost mode of operation. If defrost is commanded too soon or too late, energy will be wasted and efficiency will suffer. Unfortunately, it has been very difficult to achieve such optimum operation in the past. Moreover, these previous defrost systems are unreliable in operation and/or are not adaptable to all types of outdoor coils.
Substantially less expensive defrost control systems have also been developed, but these systems are not capable of adjusting to the prevailing weather conditions. In one such system, the differential between the outdoor ambient (dry bulb) temperature and the refrigerant temperature in the outdoor coil is measured. The outdoor coil temperature decreases as frost builds up, and this increases the temperature split or difference between the outdoor ambient temperature and the coil temperature. When the temperature split increases to a predetermined value, the outdoor coil is defrosted. These prior temperature differential type defrost controls, however, fail to take the weather conditions into account. The temperature split between the outdoor ambient air (dry bulb) temperature and the refrigerant temperature in the outdoor coil for clean coil operation is a function of the outdoor wet bulb temperature and not the dry bulb temperature. For example, when the outdoor ambient air has a 35.degree. F. dry bulb temperature, a 34.degree. F. wet bulb temperature, and a relative humidity of about 90%, the refrigerant temperature in the outdoor coil of a typical three ton heat pump may be about 23.degree. F. when the outdoor coil is frost-free, the clean coil temperature split (namely, the outdoor ambient temperature minus the outdoor coil temperature) thereby being 35.degree.-23.degree. or 12.degree.. (All temperatures mentioned herein will be F or Fahrenheit.) For the same outdoor dry bulb temperature, an outdoor wet bulb temperature of 28.degree. and an outdoor relative humidity of about 40% may then provide an outdoor coil temperature of about 17.degree., resulting in a clean coil temperature split of 35.degree.-17.degree. or 18.degree.. Neither humidity condition is uncommon in most areas. Thus, if the defrost control were set, when the ambient air has a 34.degree. wet bulb temperature, to initiate defrost at a temperature differential of, for example, 5.degree. above its expected clean coil condition, defrost would occur when the temperature differential became 12.degree.+5.degree. or 17.degree. and dry weather conditions would result in the system continually defrosting itself without time for frost buildup on the outdoor coil.
Even if the temperature split, at which defrost should occur, is properly determined when the outdoor coil is frost-free, long before frost builds up and that temperature split is reached the weather conditions (namely, the outdoor temperature and/or relative humidity) may change significantly, and that previously determined temperature split may no longer be appropriate or valid. If there is a decrease in outdoor temperature between defrost modes, excessive frost would build up on the outdoor coil and defrost should now be initiated at a smaller temperature split, not the one previously determined. On the other hand, as the outdoor temperature rises the same system may go into needless defrost because the control would assume that frost is building up on the coil, when it may not.
This phenomenon may be appreciated and more fully understood by observing FIG. 1 which provides a graph of the performance of the typical three ton heat pump mentioned previously. The graph plots the wet bulb temperature of the outdoor air versus the outdoor ambient or dry bulb temperature at different outdoor relative humidities. The graph shows the liquid line temperature, which is essentially the same as the outdoor coil temperature or the coil surface temperature, under clean coil conditions at various wet bulb temperatures. The clean coil temperature splits (the outdoor dry bulb temperature minus the liquid line temperature) for different weather conditions, namely at different points on the graph, may easily be determined by subtraction of one temperature from the other at the point that represents the weather conditions. The graph clearly illustrates that the liquid line temperature is strictly a function of the wet bulb temperature, and thus the moisture in the outdoor air.
It will be assumed that on a given day at about 7 a.m. the weather conditions in a particular area are as depicted by point 11 in FIG. 1, namely about 12.degree. outdoor ambient temperature, 10.5.degree. wet bulb temperature and about 77% relative humidity, the liquid line temperature for clean coil conditions thus being about 4.5.degree. to provide a clean coil temperature split of 12.degree.-4.5.degree. or 7.5.degree.. Point 12 indicates the assumed weather conditions on the same day at 10 a.m.--29.degree. outdoor dry bulb temperature, 23.degree. wet bulb temperature, about 40% relative humidity and a liquid line temperature of about 13.5.degree., the clean coil temperature split thereby being 29.degree.-13.5.degree. or 15.5.degree.. This corresponds to an 8.degree. increase (15.5-7.5) in the temperature split for a clean outdoor coil. If the control system were programmed, in accordance with the data at 7 a.m., to initiate defrost after there is a 4.degree. temperature increase in the clean coil temperature split, a needless defrost cycle would occur with no frost build up on the outdoor coil. Points 13 and 14 in FIG. 1 depict the assumed weather conditions at 4 p.m. and 11 p.m., respectively, on the same given day. The graph indicates that the clean coil temperature split would change downward from about 18.degree. to 11.5.degree., or about 6.5.degree., between 4 p.m. and 11 p.m. Thus, a 4.degree. programmed differential would require that the initial 18.degree. clean coil split at 4 p.m. would have to increase to 22.degree. before defrost would occur, whereas the optimum defrost split (the difference between the outdoor temperature and the coil temperature when the defrost mode should be initiated) for the weather conditions at 11 p.m. would be 11.5.degree. plus 4.degree., or 15.5.degree.. Hence, the split would increase 6.5.degree. (from 15.5.degree. to 22.degree.) above the optimum defrost condition before defrost would be initiated and excessive frost would accumulate. The conditions assumed in explaining the FIG. 1 graph are not uncommon, since the outdoor temperature and relative humidity may experience wide variations over a 24-hour period.
The defrost control system of the present invention is a substantial improvement over those previously developed. The system is not only relatively inexpensive but the initiation of outdoor coil defrost is timed to occur at the optimum point regardless of changing weather conditions so that defrost only and always occurs when it is necessary, thereby increasing the efficiency of the heat pump, conserving energy and improving system reliability. Any time there is a significant change in the weather conditions, the control system of the present invention will effectively recalculate when a defrost cycle should be initiated.


Compounds of Formula I: ##STR1##
are structurally novel antiepileptic compounds that are highly effective anticonvulsants in animal tests (Maryanoff, B. E, Nortey, S. O., Gardocki, J. F., Shank, R. P. and Dodgson, S. P. J Med. Chem. 30, 880-887, 1987; Maryanoff, B. E., Costanzo, M. J., Shank, R. P., Schupsky, J. J., Ortegon, M. E., and Vaught J. L. Bioorganic & Medicinal Chemistry Letters 3, 2653-2656, 1993). These compounds are covered by U.S. Pat. No.4,513,006. One of these compounds 2,3:4,5-bis-O-(1-methylethylidene)-.beta.-D-fructopyranose sulfamate known as topiramate has been demonstrated in clinical trials of human epilepsy to be effective as adjunctive therapy or as monotherapy in treating simple and complex partial seizures and secondarily generalized seizures (E. FAUGHT, B. J. WILDER, R. E. RAMSEY, R. A. REIFE, L D. KRAMER, G. W. PLEDGER, R. M. KARIM et. al., Epilepsia 36 (S4) 33, 1995; S. K. SACHDEO, R. C. SACHDEO, R. A. REIFE, P. LIM and G. PLEDGER, Epilepsia 36 (S4) 33, 1995), and is currently marketed for the treatment of simple and complex partial seizure epilepsy with or without secondary generalized seizures in approximately twenty countries including the United States, and applications for regulatory approval are presently pending in several additional countries throughout the world.
Compounds of Formula I were initially found to possess anticonvulsant activity in the traditional maximal electroshock seizure (MES) test in mice (SHANK, R. P., GARDOCKI, J. F., VAUGHT, J. L., DAVIS, C. B., SCHUPSKY, J. J., RAFFA, R. B., DODGSON, S. J., NORTEY, S. O., and MARYANOFF, B. E., Epilcpsia 35 450-460, 1994). Subsequent studies revealed that Compounds of Formula I were also highly effective in the MES test in rats. More recently topiramate was found to effectively block seizures in several rodent models of epilepsy (J. NAKAMURA, S. TAMURA, T. KANDA, A. ISHII, K. ISHIHARA, T. SERIKAWA, J. YAMADA, and M. SASA, Eur. J. Pharmacol. 254 83-89, 1994), and in an animal model of kindled epilepsy (A. WAUQUIER and S. ZHOU, Epilepsy Res. 24, 73-77, 1996).
Cluster headache is an excruciating painful disorder associated with considerable suffering which is characterized by severe, short duration, unilateral orbital-temporal pain, Ipsilateral autonomic dysfunction and chronobiological disturbances. (A. Kudrow, The pathogenesis of a cluster headache, Curr. Opin. Neurol. 7:278-282, 1994; Headache Classification Committee of the International Headache Society, Classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain, Cephalgia S7:1-96, 1988). Although treatment is often successful, some patients have intractable pain. Thus, a need remains for effective treatments for cluster headaches.
Studies on five patients treated with topiramate have revealed previously unrecognized pharmacological properties which suggest that topiramate is effective in treating cluster headaches.


Many aerial vehicles (e.g., manned or unmanned vehicles such as airplanes, helicopters or other airships) are configured to operate in two or more flight modes. As one example, an aerial vehicle may be configured to engage in forward flight, or substantially horizontal flight, a mode in which the aerial vehicle travels from one point in space (e.g., a land-based point or, alternatively, a sea-based or air-based point) to another point by traveling over at least a portion of the Earth. In forward flight, the aerial vehicle may be maintained aloft by one or more net forces of lift that are typically induced by airflow passing over and below wings, consistent with a pressure gradient. As another example, an aerial vehicle may be configured to engage in vertical flight, a mode in which the aerial vehicle travels in a vertical or substantially vertical direction from one altitude to another altitude (e.g., upward or downward, from a first point on land, on sea or in the air to a second point in the air, or vice versa) substantially normal to the surface of the Earth, or hovers (e.g., maintains a substantially constant altitude), with an insubstantial change in horizontal or lateral position. In vertical flight, the aerial vehicle may be maintained aloft by one or more net forces of lift that are typically induced by rotating blades of a propeller or another source. As yet another example, an aerial vehicle may be configured to engage in both forward and vertical flight, a hybrid mode in which a position of the aerial vehicle changes in both horizontal and vertical directions.
An aerial vehicle that is configured to operate in multiple modes may utilize one or more propulsion systems and/or control surfaces (e.g., wings, rudders, ailerons, flaps or other components) at different times, depending on requirements of a given mission in which the aerial vehicle is to operate in each of such modes. For example, an aerial vehicle may utilize a first set of motors or rotors when operating in forward flight, and a second set of motors or rotors when operating in horizontal flight. Likewise, the aerial vehicle may utilize a first set of control surfaces when operating in horizontal flight, and a second set of control surfaces when operating in vertical flight. When motors, rotors, control surfaces or other components of an aerial vehicle are not being utilized for propulsion or control, such components merely act as dead weight to the aerial vehicle.
The use of imaging devices or other sensors on aerial vehicles is increasingly common. In particular, unmanned aerial vehicles, or UAVs, are frequently equipped with one or more imaging devices such as digital cameras; position sensors such as Global Positioning System, or GPS, sensors; radar sensors; or laser sensors, such as light detection and ranging, or LIDAR, sensors. Such sensors aid in the guided or autonomous operation of an aerial vehicle, and may be used to determine when the aerial vehicle has arrived at or passed over a given location, when the aerial vehicle is within range of one or more structures, features, objects or humans (or other animals), or for any other purpose. Outfitting an aerial vehicle with one or more of such sensors typically requires installing housings, turrets or other structures or features by which such sensors may be mounted to the aerial vehicle. Such structures or features add weight to the aerial vehicle, and may increase the amount or extent of drag encountered during flight, thereby exacting a substantial operational cost from the aerial vehicle for the use of such sensors in exchange for their many benefits.


Usually, in the CIS-based thin film solar cell module, layers including a metallic base electrode layer, a p type light absorbing layer, a high resistance buffer layer and an n type window layer (a transparent conductive film) are respectively laminated on the surface of a substrate (109) to form the CIS-based thin film solar cell module. A filler (103) having a sealing effect such as an EVA (Ethylene-Vinyl Acetate) resin, PVB (Polyvinyl Butyral), etc. is put thereon and cover glass (102) of an upper surface is laminated and attached thereon. The obtained solar cell module is surrounded by a frame (101) made of aluminum etc. to cover an end part of the solar cell module. Between the frame and the solar cell module, a resin is sandwiched (not shown in the drawing) to prevent moisture such as water from entering from the end part of the cover glass (102) and improve a weather resistance (see FIG. 1).
On the other hand, there is a frameless solar cell module to which an aluminum frame is not attached in order to lighten the solar cell module and reduce a production cost. As such a frameless solar cell module, a solar cell module that includes a light receiving surface side film, a light receiving surface side filler, a plurality of solar cell elements electrically connected together by connecting tabs, a back surface side filler and a back surface side film which are sequentially arranged so as to be piled, and has a structure in which a peripheral edge part of the light receiving surface side film is fusion welded to a peripheral edge part of the back surface side film is proposed (see patent document 1).
Further, as another frameless solar cell module, a structure in which when a frameless solar cell module is laid on a member to be attached such as a roof of a residence having a gradient, rod shaped joint fillers are held between the solar cell modules adjacent in the direction of the gradient of the member to be attached to lay the solar cell modules so that all the rod shaped joint fillers do not protrude from the surfaces of the solar cell modules is proposed (see patent document 2).
Further, a frameless solar cell module that has an edge space (a space where device layers are not piled) provided in a periphery of a solar cell circuit is also proposed (see FIG. 2 and patent document 3). When the edge space is provided, the frame does not need to be attached and a production cost can be more reduced and the solar cell module can be more lightened than the solar cell module of a type having the frame. As a manufacturing method of the solar cell module of this type, after a laminated film (a first electrode (108)/a semiconductor layer (107)/a second electrode (104)) is formed on the entire surface of a light receiving surface side of a substrate (109), the laminated film of an area corresponding to the edge space is removed by a laser or a sandblaster etc. to form the edge space (see FIG. 2). For instance, patent document 4 discloses a technique for removing a laminated film of an edge space area by using a YAG laser.


Recently linear low density polyethylenes have become available in pelletized form and they have properties which render them desirable for use in making film by the bubble extrusion process. Unfortunately high clarity, high tack film which is essential to food packaging and pallet wrap films can only be accomplished with such LLDPE resins by chill roll casting or similar techniques which employ chilled rolls or mandrels for rapid cooling of the molten extrudate.


A muffler usually comprises two housing parts, namely two half-shells, which are joined with a seal being interposed therebetween. Such a seal must withstand high temperatures and compensate for unevenness at the sealing faces as well as withstand vibrations and gas pulsations of the muffler.
Experience has shown that the silicon seals or fiber seals normally used do not withstand the high temperatures which can be approximately 500.degree. C. so that considerable leakage can develop even after a short operating time. The arrangement of copper seals is likewise not satisfactory since warpage occurring because of high temperatures can lead to leakage and mechanical wear occurs because of unavoidable relative movements between the housing parts produced by vibration.


This invention relates generally to layered perovskite superconductors and, more particularly, to substrates on which layered perovskite superconductors are deposited to form high-frequency electronic devices and circuits.
Materials exhibiting superconductivity at temperatures above the advantageous liquid-nitrogen temperature of 77 K were discovered only recently and have triggered a world-wide explosion in scientific and technological research. The first material to exhibit superconductivity above the temperature of liquid nitrogen was an oxygen-depleted layered perovskite compound of yttrium, barium, copper and oxygen, identified by the formula Y1Ba2Cu3O7. Since this discovery, other similar layered perovskite copper oxide compounds, identified by the formula R1Ba2Cu3O7, where R is a rare earth element, have also been found to be superconductive at temperatures above the liquid-nitrogen temperature. This particular group of layered perovskite superconductors is commonly referred to as xe2x80x9c1-2-3xe2x80x9d compounds, because of the number of atoms of each metal element in the copper oxide compound.
Still other layered perovskite copper oxide compounds, with even higher critical temperatures (the temperature at which superconductivity occurs), have been more recently discovered. These newer compounds contain four metallic elements instead of the three metallic elements contained in the xe2x80x9c1-2-3xe2x80x9d compounds, and they do not contain a rare earth element. In place of the rare earth element, these newer compounds contain metals such as bismuth or thallium.
The major advantage of the layered perovskite superconductors is that superconductive temperatures can be maintained using liquid nitrogen, which is considerably less expensive and troublesome than using liquid helium, as required in the past. Therefore, these superconductors can be expected to find many new applications. One major application already being investigated is integrated circuits, in which thin films of these new superconductors are deposited on substrates to form, for example, Josephson junctions, waveguides and microwave transmission lines. These superconductor circuit elements can be combined to form high-speed, high-frequency and low-power integrated circuits with unparalleled performance.
However, thin films of the layered perovskite superconductors can only be grown with optimal properties on substrates having crystal structures and lattice constants that closely match those of the superconductors. Strontium titanate (SrTiO3) is one such material, and is currently being used as a substrate. Unfortunately, strontium titanate is unsuitable at high frequencies because it is very lossy and has an extremely high dielectric constant at superconductive temperatures. Accordingly, there has been a need for a substrate material having good high frequency characteristics and a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. The present invention clearly fulfills this need.
The present invention resides in a substrate of lanthanum aluminate (LaAlO3) on which thin films of layered perovskite copper oxide superconductors are formed. Lanthanum aluminate, with a pseudo-cubic perovskite crystal structure, has a crystal structure and lattice constant that closely match the crystal structures and lattice constants of the layered perovskite superconductors. Therefore, it promotes epitaxial film growth of the superconductors, with the crystals being oriented in the proper direction for good superconductive electrical properties, such as a high critical current density. In addition, LaAlO3 has good high frequency properties, such as a low loss tangent and low dielectric constant at superconductive temperatures. Finally, lanthanum aluminate does not significantly interact with the superconductors. Lanthanum aluminate can also be used to form thin insulating films between the superconductor layers, which allows for the fabrication of a wide variety of superconductor circuit elements.
It will be appreciated from the foregoing that the present invention represents a significant advance in the field of superconductors. Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.


Various mechanisms exist for power management in a platform. However, existing power management techniques require a process or agent to have access to all components to be managed.
Existing multi-processor platforms may have processors, devices and/or memory partitioned. One platform may then behave as two computing devices. A platform may have multiple processors with hardware partitioning so that the platform may act as multiple machines with multiple operating systems. There may be only a single motherboard on the platform.
Power utilization of platforms is becoming more important. It is desirable to minimize or optimize the power that a platform or set of platforms utilize. As partitioning becomes more prevalent, it may become desirable to manage the power utilization of the various partitions of a system and the system overall.
However, partitioning has traditionally been performed in enterprise-class machines, such as servers, and other large-size deployed machines. Power utilization has become more important as more machines are used in one location. Environmental concerns are now an issue. For instance, it may not be possible to co-locate enough compute power and maintain an appropriately cooled environment. The air conditioning unit may not be able to handle the heat dissipation of that much power utilization. With the multi-core and mini-core deployments planned for the future, many usage models require partitioning. It is becoming more common for platforms to comprise more than one processor. Further, other devices are often present in multiples within the platform.
Portions of a system may be sequestered, for partitioning. Power management in an existing system may use an agent that can monitor the processor burden rate (busy time), control throttling, etc. The agent is typically in control of the platform, but when resources are sequestered, the agent no longer maintains control of the sequestered resources. If the agent cannot see a resource, the agent can no longer manage that resource. Thus, the traditional power management schemes are no longer viable solutions for partitioned platforms with sequestering.


Mission requirements for near-future radars dictate high levels of operational capability provided by systems that are light in weight. Such radars must feature agile, reconfigurable beams coupled with high effective transmit power and high receive sensitivity.
The operational requirements are fulfilled by adopting large aperture active phased array antennas having transmit/receive (TIR) electronics distributed with the radiating elements. Distributing the active TIR circuits over the array antenna also necessitates distributing their associated prime power converters and controllers, plus providing means for effective thermal management and conveying RF/power signals. It is desirable that these phased array antennas be realized with minimum weight to promote high mobility in ground radar applications and to minimize top-side mass for shipboard systems.
Accordingly, there is a need for a lightweight active phased array antenna having distributed transmit/receive (T/R) electronics radiating elements, power converters, and controllers. Such a phased array antenna should also have effective thermal management and a mechanism for conveying the RF/power signals.


Given a data matrix X of size n by p, clustering assigns the observations (rows of X) to clusters, or groups based on some or all of the data variables (columns of X). Clustering is a cornerstone of business intelligence, with wide-ranging applications such as market segmentation and fraud detection.


Distributed database systems include a plurality of storage devices spread among a network of interconnected computers. The distributed database systems typically have greater reliability and availability than parallel database systems, among other benefits. Various internet services, for example social networking services, employ distributed database systems to manage the storage and retrieval of information. Generally, the need to efficiently and accurately read and write data across the database system increases with a greater amount of information, a greater number of users, and stricter latency requirements.
In distributed systems, there is a need for coordination and synchronization among the storage devices. In particular, the coordination and synchronization may be needed to ensure that only certain processes should perform certain tasks, ensure the proper execution of a set of functions, ensure the allocation of unique IDs, orchestrate multiple processes, and/or facilitate other coordination operations. Apache ZooKeeper™ is an example of an existing centralized service for maintaining configuration information, providing distributed synchronization, and providing group services.
However, the application programing interface (API) for ZooKeeper™ is complex such that faulty function calls or faulty services interfacing with ZooKeeper™ only fail in certain edge cases. As a result, these faulty function calls or faulty services may be difficult to detect or may otherwise go undetected, may be difficult for programmers to debug, and/or may cause difficulties in fencing. Accordingly, there is an opportunity for configurations and frameworks that decrease the complexity exposed to developers for many use-cases of a distributed database.


The present invention generally relates to the preparation of low hysteresis rubber.
The hysteresis of an elastomer refers to the difference between the energy applied to deform the elastomer and the energy recovered as the elastomer returns to its initial, undeformed state. In many industries, it is often desirable to produce elastomeric compounds exhibiting reduced hysteresis when properly compounded with other ingredients, such as reinforcing agents, and then vulcanized. Such elastomers, when compounded, fabricated, and vulcanized into components for constructing articles such as tires, power belts, and the like, will manifest properties of increased rebound and reduced heat build-up when subjected to mechanical stress during normal use. In pneumatic tires, lowered hysteresis properties are associated with reduced rolling resistance and heat build-up during operation of the tire. As a result, lower fuel consumption is realized in vehicles using such pneumatic tires.
Compounded elastomer systems are known in the art and are comprised of at least one elastomer, a reinforcing filler agent (such as carbon black or mineral fillers such as clay, silica, and the like), and a vulcanizing system. Notably, interaction between the elastomer molecules and the reinforcing filler agent(s) is known to affect hysteresis.
It has been recognized that hysteresis and other physical properties of compounded elastomer systems can be improved by ensuring good dispersion of carbon black throughout the elastomer component. In particular, it has been recognized that individual carbon black aggregates should be well dispersed in order to minimize the contact between them. By preparing elastomers with end groups capable of interacting with reinforcing fillers such as carbon black, dispersion of individual carbon black aggregates is stabilized, reducing interaggregate contacts and thereby reducing hysteresis. Thus, increased interaction between elastomer chain ends and reinforcing fillers will tend to decrease hysteretic losses.
Thus, there exists a need in the art for increasing interaction between elastomer molecules and reinforcing fillers within a compounded elastomer system. More particularly, there exists a need in the art for a terminator that provides elastomer molecules with end groups that interact with the functionality of carbon black and other reinforcing fillers. There also exists a need in the art for a process for terminating polymers with such desired end groups.
In the present invention, lithium-initiated polymers are terminated with oxazoline compounds. Useful oxazoline compounds may be selected from organic halide oxazoline compounds and branched or unbranched vinyl oxazoline compounds.
When organic halide oxazoline compounds are employed, the carbon-lithium chain end of the propagating polymer reacts with the halide provided by the oxazoline compound, and the polymer is terminated with the organic oxazoline.
When a branched or unbranched vinyl oxazoline compound is employed, the vinyl oxazoline compound is inserted between the propagating polymer and the lithium atom, thereby effectively terminating further polymer propagation with chemical units other than vinyl oxazoline compounds or, more broadly, monomers that will polymerize with a substituted acrylate anion, such as, for example, esters of methacrylic acid, acrylic acid, cyanoacrylic acid and the like.
The oxazoline ring of these terminators interacts with carbon black, and the resulting functional polymers therefore exhibit reduced hysteresis in cured, compounded rubber, when compared to unterminated, yet otherwise identical, controls.
Generally, the present invention provides a method of forming an oxazoline functionalized polymer. The method includes the steps of forming a solution of one or more anionically polymerizable monomers in an alkane solvent, and polymerizing the monomers in the presence of a lithio-containing initiator so as to produce a living lithium polymer as is known in the art. The living lithium polymer is then terminated with an oxazoline compound according to the formula (I):
wherein R1 to R5 are selected according to the following criteria:
R1 is selected from the group consisting of:
an organic halide according to the following formula (II):
wherein each R6 may be the same or different and is selected from the group consisting of a branched or linear C1-C20 alkyl moiety, a C3-C20 cycloalkyl moiety, a C6-C20 aryl moiety, and a C7-C20 alkylaryl moiety, R7 is selected from the group consisting of a branched or linear C1-C20 alkylene moiety, a C4-C20 cycloalkylene moiety, and a C6-C20 alkylarylene moiety, and X is a halogen;
a branched or unbranched vinyl moiety according to the following formula (III):
wherein R8 is selected from the group consisting of hydrogen, a branched or linear C1-C20 alkyl moiety, a C3-C20 cycloalkyl moiety, a C6-C20 aryl moiety, and a C7-C20 alkylaryl moiety;
a moiety according to formula (IV):
wherein each R6 may be the same or different and is selected according to the same criteria set forth in formula (II); and
hydrogen; and
R2-R5 may be the same or different and are selected from the group consisting of:
hydrogen;
an organic halide, xe2x80x94R7xe2x80x94X, wherein R7 is as already defined, and X is a halogen; and
a branched or linear C1-C20 alkyl moiety, a C3-C20 cycloalkyl moiety, a C6-C20 aryl moiety, and a C7-C20 alkylaryl moiety, with the proviso that if R1 is selected from either an organic halide according to formula (II) or a vinyl moiety according to formula (III), R2-R5 are selected from hydrogen, a branched or linear C1-C20 alkyl moiety, a C3-C20 cycloalkyl moiety, a C6-C20 aryl moiety, and a C7-C20 alkylaryl moiety; and if R1 is selected from either hydrogen or a moiety according to formula (IV), one of R2-R5 is selected from an organic halide, xe2x80x94R7xe2x80x94X, the other R2-R5 groups are selected from the group consisting of hydrogen, a branched or linear C1-C20 alkyl moiety, a C3-C20 cycloalkyl moiety, a C6-C20 aryl moiety, and a C7-C20 alkylaryl moiety.
The present invention also provides compounds according to the following formula:
wherein X is a halogen, and each Z is the same and is selected from the group consisting of hydrogen and a methyl group.
As mentioned, it has been found that the oxazoline ring of the terminators disclosed herein beneficially interact with carbon black to reduce hysteresis in rubbers compounded with carbon black. Thus, the present invention also provides a method for producing a tire having reduced hysteresis. This method includes terminating a lithium-initiated rubber with an oxazoline compound; and compounding the oxazoline-terminated rubber with carbon black, wherein the oxazoline compound employed to terminate the lithium-initiated rubber is selected according to formula (I) under the criteria as set forth above with respect to formula (I).


File systems organize and track where data is stored in memory and where free or available space exists in memory. Distributed or clustered file systems can store thousands or even millions of files. These files and the corresponding metadata are distributed across a large number of storage devices, such as disk drives.
Counters are used in the file system to track counts for various types of information. Many file systems use simple counters that are not distributed. This approach does not scale well on clustered file systems. Other file systems implement counters that cannot be recovered in the event of corruption without a scan of the entire file system by a file system checker (fsck). Such scans can be quite time-consuming for large file systems.
Methods and systems are needed to improve the management of counters in clustered file systems.


Wireless power transfer (WPT) or wireless energy transmission is the transmission of electrical power from a power source to a receiving device without using solid wires or conductors. Generally, the term refers to a number of different power transmission technologies that use time-varying electromagnetic fields. In wireless power transfer, a transmitter device is connected to a power source, such as the mains power line, and transmits power by electromagnetic fields across an intervening space to one or more receiver devices, where it is converted back to electric power and utilized. Wireless power techniques may fall into two categories, non-radiative and radiative.
In near-field or non-radiative techniques, power may be transferred over short distances by magnetic fields using inductive coupling between coils of wire by electric fields using capacitive coupling between electrodes, for example. Using these techniques, it may be possible to transfer power wirelessly within two meters distance with an efficiency of 70% at a frequency of 100 kHz. Applications of this type include, but are not limited to, cell phone, tablets, laptops, electric toothbrush chargers, RFID tags, smartcards, and chargers for implantable medical devices like artificial cardiac pacemakers, and inductive powering or charging of electric vehicles like cars, trains or buses. In radiative or far-field techniques, sometimes called “power beaming”, power may be transmitted by beams of electromagnetic radiation, like microwave or laser beams. These techniques can transport energy longer distances but are typically aimed at the receiver.
Numerous standardized technologies have been developed over the years, including, but not limited to, Alliance for Wireless Power (“A4WP”) which is based on an interface standard (“Rezence”) for wireless electrical power transfer based on the principles of magnetic resonance, where a single power transmitter unit (PTU) is capable of charging one or more power receiver units (PRUs). The interface standard supports power transfer up to 50 Watts, at distances up to five centimeters. The power transmission frequency may be 6.78 MHz, and up to eight devices can be powered from a single PTU depending on transmitter and receiver geometry and power levels. A Bluetooth Smart link may be provided in an A4WP system for controlling power levels, identification of valid loads, and protection of non-compliant devices.
Another standardized WPT technology includes “Qi” which relies on electromagnetic induction between planar coils. A Qi system may include a base station, which is connected to a power source and provides inductive power, and a device that consumes inductive power. The base station may include a power transmitter having a transmitting coil that generates an oscillating magnetic field; the device may include a power receiver holding a receiving coil. The magnetic field from the transmitter may induce an alternating current in the receiving coil by Faraday's law of induction. A further standardized WPT technology includes “Powermat” adopted by the Power Matters Alliance (PMA), which is based upon inductively coupled power transfer, where a transmitter may vary current in a primary induction coil to generate an alternating magnetic field from within a charging spot. The receiver in the consuming device may have its own induction coil that takes power from the magnetic field and converts it back into electrical current to charge the device battery. An additional part of the technology is the use of system control communication via Data over Coil (DoC), where the receiver may send feedback to the transmitter by changing the load seen by the transmitter coil. The protocol is frequency based signaling, thus enabling fast response of the transmitter.
In WPT systems, it is often necessary to place a consuming device, having a receiver antenna, within the general area and range of a WPT transmitter in order to receive power. While adequate power may be provided when the consuming device is physically placed in the general area and range of the WPT transmitter, the placement may not be optimal, which may result in less-than optimal power transfer. In cases where the receiving entity is of a larger size (e.g., car, truck, train, etc.) this problem may be compounded. Accordingly, technologies are needed to optimize wireless charging alignment between a WPT transmitter and one or more receivers.


A. Technical Field
The present invention relates to an ink jet recording material and a coating agent therefor, more particularly, relates to: an ink jet recording material which displays sufficient water resistance and further, excellent definition of initial images; and a coating agent therefor to give such an ink jet recording material.
Ink jet recording apparatuses are machines such as printers, facsimile machines, and copiers. For the ink jet recording apparatus, U.S. Pat. No. 5,486,854 issued Jan. 23, 1996 is hereby incorporated by reference. The ink jet recording apparatus is to make a recording by jetting ink from a recording means (i.e. a recording head which is a part of the ink jet recording apparatus) onto a recording material, wherein the recording material is, for example, a paper sheet, or a plastic sheet such as transparent PET sheet.
The ink jet recording material, generally, suffers from a lack of water resistance. That is, an exposure to water usually will dissolve and destroy the image (the imaged ink). To prevent this, the image must be rendered water-resistant, and further, if the ink is, for example, an organic dye, then the image must also be fixed. Examples of known methods of giving the image the water resistance to thereby fix the image include arts to fix dyes with mordants and arts involving the use of adsorptive pigments. However, operations thereof are complicated, or the optimal method is different according to the composition of the ink, so the above known methods are not commonly usable means.
In comparison, JP-A-035090/1998 discloses a water-resistant composition for ink jet recording sheets, comprising a polymer containing an amino group (and/or quaternary ammonium salt) and a carboxyl group (and/or acid anhydride) and a crosslinking agent containing at least two oxazoline groups, as a method of not giving the image the water resistance, but carrying out a water-resisting pretreatment for the recording material. However, as to this technique, not only is the resultant water-resistification insufficient, but also there are problems on the definition of initial images.
An object of the present invention is to provide: an ink jet recording material which displays sufficient water resistance and further, excellent definition of initial images; and a coating agent therefor to give such an ink jet recording material.
To solve the above problems, the present invention provides the following:
A first coating agent for ink jet recording materials, according to the present invention, comprises: an aqueous polymer having a carboxyl group; and a water-soluble polymer having an oxazoline group as a crosslinking agent.
A second coating agent for ink jet recording materials, according to the present invention, comprises a polymer and a crosslinking agent, wherein the polymer has both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group.
An ink jet recording material, according to the present invention, has on at least one face thereof a coated and cured layer of the above present invention first coating agent and/or a coated and cured layer of the above present invention second coating agent.
These and other objects and the advantages of the present invention will be more fully apparent from the following detailed disclosure.
The first coating agent, according to the present invention, comprises: an aqueous polymer having a carboxyl group; and a water-soluble polymer having an oxazoline group as a crosslinking agent.
The aqueous polymer having a carboxyl group is not especially limited if it is a polymer that has a carboxyl group and further is aqueous (that is, water-soluble or water-dispersible). To obtain the polymer having a carboxyl group, a monomer having a carboxyl group is, for example, polymerized as a raw material, or a carboxyl group is introduced into a polymer (as prepared beforehand) by denaturation. To obtain the aqueous polymer, a hydrophilic monomer (available whether it has a carboxyl group or not) is, for example, used in the ratio of preferably 10 mol % or higher, more preferably 50 mol % or higher, to the entire monomer component.
Examples of the monomer having a carboxyl group include: unsaturated monocarboxylic acids, such as acrylic acid, methacrylic acid, and crotonic acid; unsaturated dicarboxylic acids, such as maleic acid, itaconic acid, citraconic acid, and fumaric acid; and unsaturated dicarboxylic anhydrides, such as maleic anhydride, itaconic anhydride, and citraconic anhydride.
Examples of the method, in which a carboxyl group is introduced into a polymer (as prepared beforehand) by denaturation, include a method including the step of jumping up a polymer, having an OH group in opposite terminal portions, with pyromellitic dianhydride.
Examples of the hydrophilic monomer include: monomers having a carboxyl group; and other monomers, such as hydroxyethyl acrylate, hydroxyethyl methacrylate, vinylpyrrolidone, dimethylaminoethyl acrylate, and chloridized-triaminoethyl methacrylate.
Examples of the aqueous polymer having a carboxyl group, as preferably usable in the present invention, include: polyvinyl alcohols having a carboxyl group (for example, anionic KEPS series made by Dai-ichi Kogyo Seiyaku Co., Ltd., and K Polymer made by Kuraray Co., Ltd.); (meth)acrylic ester copolymers (for example, Arolon made by Nippon Shokubai Co., Ltd.); vinyl ether-maleic anhydride copolymers (Gantrez AN series made by ISP); and aqueous polymers having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group. Particularly preferable ones are the aqueous polymers having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group.
Examples of the above aqueous polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group include a polymer having a structural unit of general formula (1) below:
wherein: each of R1 and R2, independently of each other, denotes a
hydrogen atom or a methyl group;
R3 denotes a divalent organic residue;
R4 denotes a monovalent organic residue;
Z denotes a halogen atom;
a denotes an integer of 1xcx9c1,000;
b denotes an integer of 3xcx9c110,000; and
n denotes an integer of 3xcx9c5,000.
This polymer can be synthesized by carrying out cationic polymerization of an oxazoline compound in the presence of an unsaturated halide to synthesize a polyoxazoline macromonomer having a radical-polymerizable double bond at a polymerization-initiating terminal, and then copolymerizing this polyoxazoline macromonomer and a monomer having a carboxyl group, as is illustrated by the following chemical reaction formula:
wherein R1, R2, R3, R4, Z, a, b, and n are the same as those in general formula (1).
Examples of the oxazoline compound, as usable in the above cationic polymerization, include 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-(n-propyl)-2-oxazoline, 2-(i-propyl)-2-oxazoline, 2-(n-butyl)-2-oxazoline, 2-(i-butyl)-2-oxazoline, and 2-(t-butyl)-2-oxazoline. Preferable ones among them are compounds with not more than 3 carbon atoms in R4, of which specific examples include 2-ethyl-2-oxazoline.
Examples of the above unsaturated halide include chloromethylstyrene, allyl chloride, epichlorohydrin, and chloroethyl vinyl ether. A preferable one among them is chloromethylstyrene.
As to the monomer having a carboxyl group, compounds in which R2 is a hydrogen atom or a methyl group are preferable among the above-exemplified monomers having a carboxyl group. Specific examples of such compounds include acrylic acid and methacrylic acid.
Therefore, preferable examples of the aqueous polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group include poly(2-methyl-2-oxazoline)/(meth)acrylic acid copolymers, poly(2-ethyl-2-oxazoline)/(meth)acrylic acid copolymers, poly(2-(n-propyl)-2-oxazoline)/(meth)acrylic acid copolymers, poly(2-(i-propyl)-2-oxazoline)/(meth)acrylic acid copolymers, poly(2-(n-butyl)-2-oxazoline)/(meth)acrylic acid copolymers, poly(2-(i-butyl)-2-oxazoline)/(meth)acrylic acid copolymers, and poly(2-(t-butyl)-2-oxazoline)/(meth)acrylic acid copolymers.
The above aqueous polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group is available whether it contains a structural unit other than the structural unit of general formula (1) above or not.
In addition, in the above general formula (1), a is an integer of 1xcx9c1,000, preferably 1xcx9c500, and b is an integer of 3xcx9c10,000, preferably 3xcx9c5,000, and n is an integer of 3xcx9c5,000, preferably 10xcx9c5,000, more preferably 2xcx9c100, still more preferably 5xcx9c500.
The weight-average molecular weight of the above aqueous polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group is preferably in the range of 50,000xcx9c1,000,000, more preferably 100,000xcx9c500,000.
Examples of the water-soluble polymer having an oxazoline group as a crosslinking agent, as contained in the first coating agent according to the present invention, include a polymer containing an oxazoline group as obtained by polymerizing a monomer component which comprises an addition-polymerizable oxazoline and, if necessary, further comprises a monomer copolymerizable therewith. Examples of the addition-polymerizable oxazoline include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-4-ethyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and 2-isopropenyl-4,5-dimethyl-2-oxazoline. These may be used either alone respectively or in combinations with each other. A preferable one among them is 2-isopropenyl-2-oxazoline, because it is industrially easily available.
The amount of the addition-polymerizable oxazoline, as used, is not especially limited, but is preferably 5 weight % or larger, more preferably in the range of 30xcx9c60 weight %, of the entire monomer component. In the case where the amount is smaller than 5 weight %, the extent of the curing is insufficient. In the case where the amount exceeds 60 weight %, it will have a bad effect on the water resistance.
Examples of the monomer copolymerizable with the addition-polymerizable oxazoline include: (meth)acrylic esters, such as methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-aminoethyl (meth)acrylate and its salts; unsaturated nitriles, such as (meth)acrylonitrile; unsaturated amides, such as (meth)acrylamide, N-ethylol(meth)acrylamide, and N-(2-hydroxyethyl)(meth)acrylamide; vinyl esters, such as vinyl acetate and vinyl propionate; vinyl ethers, such as methyl vinyl ether and ethyl vinyl ether; xcex1-olefins, such as ethylene and propylene; halogen-containing xcex1,xcex2-unsaturated monomers, such as vinyl chloride, vinylidene chloride, and vinyl fluoride; and xcex1,xcex2-unsaturated aromatic monomers, such as styrene, xcex1-methylstyrene, and sodium styrenesulfonate. These may be used either alone respectively or in combinations with each other.
To obtain the water-soluble polymer, the ratio of the hydrophilic monomer to the entire monomer component to be polymerized is preferably 50 weight % or higher, particularly preferably in the range of 60xcx9c90 weight %. Examples of the hydrophilic monomer include addition-polymerizable oxazolines, 2-hydroxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polyethylene glycol mono(meth)acrylate, and 2-aminoethyl (meth)acrylate and its salts, and further, sodium (meth)acrylate, ammonium (meth)acrylate, (meth)acrylonitrile, (meth)acrylamide, N-methylol(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and sodium styrenesulfonate, as are selected from among the aforementioned monomer components.
The aqueous polymer having a carboxyl group is contained in the first coating agent in the ratio of preferably 5xcx9c95 weight %, more preferably 10xcx9c90 weight %, still more preferably 50xcx9c90 weight %, in terms of solid content, to the entire weight of the first coating agent. The water-soluble polymer having an oxazoline group, as used as the crosslinking agent, is contained in the first coating agent in the ratio of preferably 5xcx9c95 weight %, more preferably 10xcx9c90 weight %, still more preferably 10xcx9c50 weight %, in terms of solid content, to the entire weight of the first coating agent.
The first coating agent may further comprise components other than the aqueous polymer having a carboxyl group and the water-soluble polymer having an oxazoline group as the crosslinking agent, if necessary. Examples of such other components include: curing catalysts, such as paratoluenesulfonic acid (PTSA); organic or inorganic fine particles; dye mordants; pigments; dispersants; and ultraviolet absorbing agents.
The second coating agent, according to the present invention, comprises a polymer and a crosslinking agent, wherein the polymer has both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group. Incidentally, this xe2x80x9cpolymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl groupxe2x80x9d is mentioned in detail above.
Examples of the crosslinking agent, as used for the second coating agent, include the water-soluble polymer having an oxazoline group as mentioned in detail above, and further, melamine, aziridine, isocyanate, and epoxy.
The polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group is contained in the second coating agent in the ratio of preferably 5xcx9c95 weight %, more preferably 10xcx9c90 weight %, still more preferably 50xcx9c90 weight %, in terms of solid content, to the entire weight of the second coating agent. The crosslinking agent is contained in the second coating agent in the ratio of preferably 5xcx9c95 weight %, more preferably 10xcx9c90 weight %, still more preferably 10xcx9c50 weight %, in terms of solid content, to the entire weight of the second coating agent.
The second coating agent may further comprise components other than the polymer having both a structural unit, as formed by ring-opening polymerization of an oxazoline compound, and a carboxyl group and the crosslinking agent, if necessary. Examples of such other components include: curing catalysts, such as paratoluenesulfonic acid (PTSA); organic or inorganic fine particles; dye mordants; pigments; dispersants; and ultraviolet absorbing agents.
The ink jet recording material, according to the present invention, has on at least one face thereof a coated and cured layer of the present invention first coating agent and/or a coated and cured layer of the present invention second coating agent.
The ink jet recording material is a sheet-shaped material as used to record images thereon with ink jet recording apparatuses. Examples of such ink jet recording materials include: paper, synthetic paper such as Tyvek (made by E.I. Du Pont DE NEMOURS and Co., Ltd.); cloths, such as canvas, clothing fabrics and non-woven composites; films or sheets of plastics such as polyvinyl chloride, polypropylene, and polyethylene terephthalate (PET).
The amount of the present invention first or second coating agent, as coated, is preferably in the range of 3xcx9c50 g, more preferably 5xcx9c40 g, per square meter. In the case where the amount is smaller than 3 g, water cannot sufficiently be absorbed from ink. In the case where the amount exceeds 50 g, much time and energy are necessary for drying the sheet. In addition, the coating thickness is preferably in the range of 1xcx9c50 xcexcm, more preferably 5xcx9c40 xcexcm. In the case where the coating thickness is less than 1 xcexcm, water cannot sufficiently be absorbed from ink. In the case where the coating thickness exceeds 50 xcexcm, the improvement of the ink absorbency cannot be expected very much, so there are economical disadvantages.
The curing temperature is preferably in the range of 50xcx9c200xc2x0 C., more preferably 80xcx9c150xc2x0 C. The curing time depends on the curing temperature, but is preferably in the range of 1xcx9c60 minutes, more preferably 1xcx9c30 minutes.
(Effects and Advantages of the Invention):
Coating an ink jet recording material with the present invention coating agent for ink jet recording materials can give an ink jet recording material which displays sufficient water resistance and further, excellent definition of initial images.
Hereinafter, the present invention is more specifically illustrated by the following examples of some preferred embodiments in comparison with comparative examples not according to the invention. However, the invention is not limited to the below-mentioned examples. In addition, in the examples, unless otherwise noted, the units xe2x80x9c%xe2x80x9d and xe2x80x9cpart(s)xe2x80x9d denote those by weight.
 less than Synthesis of FX-AA as an Aqueous Polymer having a Carboxyl Group and further a Structural Unit of General Formula (1) greater than
A mixture of 297 g of 2-ethyl-2-oxazoline, 9.2 g of chloromethylstyrene (mixture of m- and p-isomers) and 252.4 g of ethanol was charged into a 1-liter autoclave, and then heated at 130xc2x0 C. for 4 hours, thus obtaining an ethanol solution of poly(2-ethyl-2-oxazoline) macromonomer with a styrene functional group at a polymerization-initiating terminal. Then, 43.2 g of acrylic acid, 3.5 g of 2,2xe2x80x2-azobis(isobutyronitrile) and 50 g of ethanol were added to this ethanol solution, and the resultant mixture was heated within the range of 105 to 135xc2x0 C. for 6 hours. The reaction mixture was cooled, thus obtaining an ethanol solution of a poly(2-ethyl-2-oxazoline) macromonomer/acrylic acid copolymer (655.3 g of FX-AA; solid content=59.6 weight %).
 less than Synthesis of Water-soluble Polymer (A) having an Oxazoline Group as a Crosslinking Agent greater than
A mixture of 29 parts of deionized water and 1 part of V-50 (polymerization initiator made by Wako Pure Chemical Industries, Ltd.: 2,2xe2x80x2-azobis(2-amidinopropane) dihydrochloride) were charged into a flask having a stirrer, a reflux condenser, a nitrogen-introducing tube, a dropping funnel, and a thermometer, and then heated to 60xc2x0 C. under a slow nitrogen gas current. Thereto, a monomer mixture was added from the dropping funnel over a period of 1 hour, with this monomer mixture having been prepared beforehand and comprising 0.4 parts of ethyl acrylate, 5.6 parts of methyl methacrylate, 4 parts of methoxypolyethylene glycol methacrylate (NK Ester AM-90G made by Shin-Nakamura Chemical Industrial Co., Ltd.), and 10 parts of 2-isopropenyl-2-oxazoline. During the reaction, nitrogen gas was continuously run, and the temperature in the flask was kept at 60xc2x11xc2x0 C. After the end of the addition, the same temperature was maintained for 9 hours, and then the mixture was cooled, thus obtaining an aqueous solution of a polymer (water-soluble polymer (A)) containing a 2-oxazoline group, of which the nonvolatile content was 40%, and the pH was 8.3.


Recent rapid advances in the development of data processors and software implementations are making more and more data processing services available to users. Basic services, such as the processing and manipulation of data in response to instructions and commands and the managing of data including storing such data in records and files, modifying the stored data and reading the stored data are now within economic reach of both small and large users. Typically, the processing is provided by one or more digital computers cooperating with externally connected user devices, such as data terminals, which may provide the data to be manipulated, managed or transferred or the commands and instructions for the data.
Some "users" of data processing services may find it preferable to process data in their own, on-premises, host computer. A single such "user" may have widely geographically separate "subsidiary" locations (such as "outlets" for a manufacturer) and thus have need for processing services at these various locations. One solution is to send all raw data through the common carrier network to the "user" host and return processed data, as needed, to terminals at the "outlet locations". Another solution is to provide distributed processing services at or near the various terminal locations to reduce the carrier network communications between each terminal and the host computer. More specifically, in accordance with the latter solution, it is advantageous to provide local services such as editing of "text", interpretation of commands, creation of forms, accumulation and manipulation of numerical and text data and the like, at locations adjacent or near to the several terminals. The carrier network communication between the host and the terminals is then limited to data after such accumulation, manipulation and editing at the various locations. It has been suggested that the provision of such distributed processing services can be appropriately handled by a service vendor for a plurality user "customers", reducing the cost for each "customer" by time-sharing the usage of processing equipment among such plurality of "customers".
Since each customer has unique and differing processing needs, individualized programs, specially tailored for these needs, must be available for the several customers. It is therefore clear that each distributed processing location (or node) for the above-described service necessarily must accommodate a large number of programs (for a plurality of customers) and each node might preferably comprise a plurality of processors or CPUs, each processor supporting a plurality of programs. As is well known in the art, only one program can actually be "executing" at any given time in a computer. However, if the program currently running should terminate, time-out, or go into a "wait" state pending the occurrence of some "event", such as the completion of any input/output operation, another program is immediately available to begin executing, thus permitting different customer programs the opportunity to time-share computer time.
In discussing the execution of a program, it is important to understand the concept of "processing". A process is the total environment in which a program (or image) executes and has, in addition to the image, three further components, namely: (1) memory space allocated to the process for storing the image, for storing data generated and used by the image and for storing control information; (2) a software context which includes such pieces of information such as priorities and privileges allocated to the process, a unique process identifier, accounting information and so on; and (3) a hardware context which comprises the contents at any instant of time of the general purpose registers within the processor or CPU. Whenever execution of the process is suspended, its hardware context is stored in memory before another process begins execution. When a process is again allowed to execute, its hardware context is restored in the registers so that the process can resume execution at the point it was interrupted without again processing previously manipulated data or reexecuting commands or instructions.
As previously noted, each customer of a service vendor typically has needs and requirements that differ from, in part, and are similar to, in part, the needs and requirements of other customers. To satisfy these diverse customers, it is advantageous for the service vendor to create an individual process to execute each "customized" program developed for the unique needs of each customer and create other processes to execute programs having "universal capabilities" which satisfy common needs of a plurality of customers.
A communication subsystem for transferring data between the several processes is a critical element in an integrated distributed-processing system suitable for diverse time-sharing customers or users. An important attribute in such a communication subsystem is to identify and select process-to-process connections in response to a request from an originating process to call a terminating end-point process which may be in a different processor in the same or in a different node and to provide communication criteria or parameters for the call, such as a rate of data flow and a grade of service. It is therefore advantageous to pass data defining such communication parameters over external communication links between the processors and the nodes (by way of foreign systems such as common carrier networks) so that the end point (users) can process such communication parameter data and intercommunicate within the parameters.
In order to communicate over another (foreign) system, an interface is required to convert the "processed" data to information suitable for conveyance over the "foreign" system. This interface which provides the suitable conversion is necessarily transparent to the communication parameter data provided by (and destined to) the end-point users. This limits the usefulness of the interface since it must be "blind" to the parameter data and thus cannot receive calls as would an end-point user or process. It is an object of this invention to enhance the usefulness of an interface process.


1. Field
This disclosure generally relates to repeaters in wireless communication systems.
2. Background
Wireless communication systems and techniques have become an important part of the way we communicate. However, providing coverage can be a significant challenge to wireless service providers. One way to extend coverage is to deploy repeaters.
In general, a repeater is a device that receives a signal, amplifies the signal, and transmits the amplified signal. FIG. 1 shows a basic diagram of a repeater 110, in the context of a cellular telephone system. Repeater 110 includes a donor antenna 115 as an example network interface to network infrastructure such as a base station 125. Repeater 110 also includes a server antenna 120 (also referred to as a “coverage antenna”) as a mobile interface to mobile device 130. In operation, donor antenna 115 is in communication with base station 125, while server antenna 120 is in communication with mobile devices 130.
In repeater 110, signals from base station 125 are amplified using forward link circuitry 135, while signals from mobile device 130 are amplified using reverse link circuitry 140. Many configurations may be used for forward link circuitry 135 and reverse link circuitry 140.
There are many types of repeaters. In some repeaters, both the network and mobile interfaces are wireless; while in others, a wired network interface is used. Some repeaters receive signals with a first carrier frequency and transmit amplified signals with a second different carrier frequency, while others receive and transmit signals using the same carrier frequency. For “same frequency” repeaters, one particular challenge is managing the feedback that occurs since some of the transmitted signal can leak back to the receive circuitry and be amplified and transmitted again.
Existing repeaters manage feedback using a number of techniques; for example, the repeater is configured to provide physical isolation between the two antennae, filters are used, or other techniques may be employed.


1. Field of the Invention
The present invention relates to a semiconductor memory device, and particularly to a semiconductor memory device suitable for mounting on a portable terminal.
2. Description of the Background Art
Semiconductor memory devices, which are used in portable terminals such as cellular phones, employ pseudo-SRAMs (Static Random Access Memories) for achieving large capacities and easy control. The pseudo-SRAM includes DRAM (Dynamic Random Access Memory) cells as internal memory cells, and also includes an interface, which is asynchronous to a clock similar to that of a SRAM, as an external interface for defining input control signals and address signals. A refresh operation is not controlled by an externally applied signal, but is performed internally and automatically (e.g., see Japanese Patent Laying-Open No. 2002-352577).
For further achieving a high speed operation, a synchronous pseudo-SRAM, which additionally employs a synchronous interface, has been available, e.g., as CellularRAM® disclosed on the Internet Web site (URL: http://www.micron.com/products/psram/cellularram/). This synchronous pseudo-SRAM includes a synchronous interface synchronized with a clock similar to that of a SRAM in addition to an asynchronous interface not synchronized with the clock.
According to the synchronous pseudo-SRAM, a WAIT signal is issued to notify that external access is prohibited, before elapsing of a command latency CL, which is the number of clocks issued until data is output after reception of a read or write request, and while self-refresh is being performed. In a conventional structure, command latency CL is externally applied. However, the synchronous pseudo-SRAM does not require such external application because the WAIT signal can be internally issued to notify that the access is impossible. Command latency CL of a more appropriate value can be determined by internally determining it within the synchronous pseudo-SRAM according to a current state, as compared with the case of externally determining the command latency.
In contrast to the above, Japanese Patent Laying-Open No. 2001-155484 has disclosed a latency determining circuit, which can adjust a latency according to a clock frequency. This latency determining circuit includes a latency determining instruction input unit, which issues an internal start signal in response to activation of a latency determination start signal for starting latency determination in synchronization with a clock signal, a latency section defining circuit, which issues a predetermined latency determination section signal at every edge of the clock signal in response to the latency determination start signal, a delay unit issuing a delay signal to adjust the latency by delaying the internal start signal by a predetermined time, and a latency instructing circuit, which determines a latency number in response to the latency determination start signal and the latency determination section signal at the point in time of activation of the delay signal. The latency determining circuit described above can internally determine the latency without an external instruction.
For example, Japanese Patent Laying-Open No. 07-226077 has disclosed a method, in which self-refresh is performed simultaneously with reading or writing in the case where a pseudo-SRAM has multiple banks. More specifically, according to the paragraph [0020] in Japanese Patent Laying-Open No. 07-226077, even when one of first to fourth cell banks 10-13 is in a refresh mode, first to fourth row address latch circuits and buffers 80-83 can transmit second load address signals A0-An-2 latched by a row address latch circuit 70 to remaining three cell banks to allow access to data even during the refresh mode.
However, the following problems arise in the methods disclosed in the foregoing references.
Although Japanese Patent Laying-Open No. 2001-155484 has disclosed a manner of internally setting the latency, it has not disclosed timing for setting the latency.
Although Japanese Patent Laying-Open No. 07-226077 has disclosed a manner of performing the refresh simultaneously with reading or writing when the bank to be refreshed is different from the bank of a reading or writing target, it has not disclosed a manner of determining the bank to be refreshed such that the bank to be refreshed may not overlap with the bank of the reading or writing target.
Further, in a structure having a plurality of pseudo-SRAMs accommodated in a single package, each pseudo-SRAM performs the refreshing according to timing different from the timing of the others. This results in a conflict of the WAIT signals issued from the respective pseudo-SRAMs.
Further, there is such a problem that data cannot be output according to timing earlier than the timing defined by command latency CL.
In the case where the pseudo-SRAM has multiple modes such as a synchronous mode and an asynchronous mode, and operates in one mode selected from these modes, a preamplifier, which can operate appropriately in a certain mode, may not operate appropriately in another mode, and thus may not correctly perform amplification.
In the case where a processing target changes to a next row during continuous reading or writing, a byte mask signal must be applied after an externally applied WAIT signal notifies of the completion of processing for starting processing of a next row (i.e., deactivation of a word line in the last processed row, activation of a word line in the next target row, amplification by a sense amplifier and others).
For precharging a bit line pair, a chip enable signal must be externally deactivated, and thus external control is required.
Semiconductor memory devices such as a CellularRAM® cannot operate synchronously with a clock of a low frequency.
When a chip is on standby, or is inactive because another chip is being accessed, an input/output buffer continues an operation, and thus wastes a current.