A system, method and computer program product are provided for improving display characteristics in a computer graphics pipeline. Initially, color data is received from memory of the computer graphics pipeline. Thereafter, the saturation and/or sharpness of the color data is altered for improving display characteristics. Next, the color data is outputted for being displayed by a display device.

The present invention relates to computer graphics, and more particularly to improving display characteristics in a computer graphics processing pipeline.
Prior art FIG. 1 illustrates a graphics system 100 constructed in accordance with the prior art. As shown, such graphics system 100 includes a graphics processor 102, a frame buffer 104, an RGB look-up table 106, digital-to-analog converters 108, and a display device 110.
The graphics processor 102 traditionally may include a transform module, a lighting module, a rasterizer and/or any other components commonly utilized in a computer graphics pipeline. Together, such components may be dedicated to rendering picture element (pixel) data that is to be displayed on the display device 110. The pixel data that is displayed on the display screen may be stored in the frame buffer 104 of the graphics system 100 in a digital pixel format.
During operation, the contents of the frame buffer 104 repeatedly are read out of the frame buffer 104 for the purpose of looking up appropriate digital RGB values utilizing the RGB look-up table 106. Such digital values are then fed to the digital-to-analog converters 108, which convert the digital RGB values into analog representations of the colors red, green and blue in order to be shown on the display device 110. In the alternative, the digital values may be fed directly to a digital display device 110.
For pixels that encode color using separate red, green, and blue values, saturation is proportional to the difference between these three values. Increasing the difference, while keeping their average the same, increases saturation. Note Prior Art FIG. 2.
Many problems result from there being a lack of control of saturation and other graphics parameters such as sharpness in graphic systems. For example, display devices 110 are often utilized in lighted environments, e.g. offices, etc. When external light falls on the face of a display device 110, some reflects back and is added to the emitted image. This reduces contrast, sharpness, and saturation. Further, graphics-intensive applications such as games or the like are often developed utilizing high-quality graphics systems and monitors. In use, however, such graphics-intensive applications are usually executed utilizing lower quality hardware, thus affording lower graphics quality.
There is thus a need for improving display characteristics, i.e. saturation, sharpness, etc. inside a computer graphics pipeline.
A system, method and computer program product are provided for improving display characteristics in a computer graphics pipeline. Initially, color data is received from memory of the computer graphics pipeline. Thereafter, the saturation of the color data is altered in the computer graphics pipeline for improving display characteristics. Next, the color data is outputted for being displayed by a display device.
In one embodiment of the present invention, the color data may include a red value, a green value, and a blue value (RGB values). Further, the saturation of the color data may be altered utilizing the following equations:
red value=red value+(red value+red valuexe2x88x92green valuexe2x88x92blue value)/2n;
green value=green value+(green value+green valuexe2x88x92red valuexe2x88x92blue value)/2n;
and
blue value=blue value+(blue value+blue valuexe2x88x92red valuexe2x88x92green value)/2n;
where n is selected from the group of numbers consisting of four (4), eight (8), and sixteen (16). One of the RGB values of the color data is thus altered based on the values of the remaining RGB values. It should be noted that the foregoing equations may include any arbitrary non-zero denominator. Optionally, the color data may be subsequently clamped based on a predetermined threshold.
In another embodiment of the present invention, the step of altering the color data may include sharpening the color data. As set forth earlier, the color data may include RGB values. Further, the color data may be sharpened by increasing a difference between a current, and previous and next values thereof.
These and other advantages of the present invention will become apparent upon reading the following detailed description and studying the various figures of the drawings.

System, method and computer program product for altering saturation in a computer graphics pipeline


Data read out from each memory cell in a memory cell array is compared with an expected value by a comparator, and the quality of a memory cell is determined by performing program verify and erase verify. Based on the comparison result of the comparator, a detected defective cell is repaired by replacing it with a spare cell. Every time a defective cell is replaced with a spare cell, information on the defective cell is stored in a register, and whether a defective cell exists and whether the repair is possible are determined on the basis of the information. When the repair is possible, a control circuit is caused to execute control, and a detected defective cell is repaired by replacing it with a spare cell. When the repair is impossible, the defect repair stops.

1. Field of the Invention
The present invention relates to a semiconductor device and test method therefor, and is applied to tests for, e.g., a memory equipped with a redundancy circuit and a memory-embedded microcomputer.
2. Description of the Related Art
Highly integrated semiconductor devices require a manufacturing process which adopts more advanced micropatterning. The efficiency percentage, i.e., yield of products sensitively depends on the presence of dust and dirt in the manufacturing process, variations in process, and the like. The percentage of complete nondefectives in which all bits are nondefective is naturally low for highly integrated memories. Under such a circumstance, the yield must be increased by a technique of preparing redundancy spare cells in addition to memory cells of a necessary capacity, and replacing a defective memory cell with a spare cell to repair the defective memory cell (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2000-57795).
However, the cost of tests is high and occupies a large portion of the unit cost of a memory equipped with a redundancy circuit or a memory-embedded microcomputer. This is because the above-mentioned technique requires not only a time taken to test the function and reliability of a memory cell but also a function test for checking the function of the entire memory area including a defective cell repair redundancy circuit and a test for checking whether a defective cell can be repaired.
In general, after the manufacturing process of a memory ends, a function test is conducted on the initial stage. If a defective cell is detected, it is repaired by a redundancy circuit, and then the process advances to the next test step. The function test on the initial stage is done following, e.g., the next procedures.
Write/read and erase/read are executed at a high temperature for respective chips of a wafer having undergone the manufacturing process, and a fail bit map is created by a memory tester. The presence/absence of defective cells is determined on the basis of the fail bit map. If no defective cell exists, the chip is determined to be nondefective, and the process normally ends. If a defective cell exists, whether the repair is possible is determined on the basis of the fail bit map. If it is determined on this stage that the repair is impossible, the chip is determined to be a defective chip, and the test ends. If the repair is determined to be possible, the defective chip is repaired by replacing with a spare cell a defective cell at an address stored on the fail bit map. The function test is conducted again to check whether the replaced spare cell functions normally.
In the function retest, write/read and erase/read are executed at a high temperature in the above-described way, and a fail bit map is created by the memory tester. The presence/absence of defective cells is determined on the basis of the fail bit map. If no defective cell exists, the chip is determined to be nondefective, and the process normally ends. If a defective cell exists, whether the repair is possible is determined on the basis of the fail bit map. If the repair is determined to be impossible, the chip is determined to be a defective chip, and the test ends. If the repair is determined to be possible, the defective chip is repaired by replacing with a spare cell a defective cell at an address stored on the fail bit map. The function test is then conducted again.
This operation is repeated for memory cells at all addresses as far as spare cells remain. The chip quality can be determined, and a defective cell can be repaired by replacing it with a spare cell.
At this time, the problem lies in the memory function test and the redundancy replacement time. This test poses problems (1) to (4) because a fail bit map is created using the memory tester and the function test and redundancy replacement are executed on the basis of the fail bit map.
(1) In order to create a fail bit map using the memory tester, data must be written from the memory tester to a memory (chip) and read out from the chip to the memory tester. A long time is taken for data transfer between the chip and the tester. For a large-capacity memory, a large amount of data must be transferred from the tester and written, and a large amount of data must be read out and transferred to the tester. A long time is taken for the data transfer.
(2) The address width of a memory and its data width capable of read/write at once are determined by chip specifications, and the input/output data amount is limited. For example, to input/output 32-bit data to/from a chip capable of 8-bit external input/output, the data must be divided into four and separately read/written. As a result, the data read/write time becomes long.
(3) Creation of a fail bit map needs an expensive memory tester and complicated processes.
(4) A dedicated program is necessary for recognizing the address of a defective cell subjected to redundancy replacement on the basis of the fail bit map created by the memory tester.
As described above, the conventional semiconductor device and test method therefor suffer a long test time and high test cost. The rise in test cost is reflected in the cost of the semiconductor device, and increases the unit cost of the product.

Semiconductor device and test method thereof


An active device provided by the invention is disposed on a substrate and includes a gate, a gate insulating layer, an oxide semiconductor channel layer, a plurality of nano conductive wires, a source and a drain. The gate insulating layer is disposed between the gate and the oxide semiconductor channel layer. The nano conductive wires are distributed in the oxide semiconductor channel layer, in which the nano conductive wires do not contact the gate insulating layer and the nano conductive wires are arranged along a direction and not intersected with each other. The source and the drain are disposed on two sides opposite to each other of the oxide semiconductor channel layer, in which a portion of the oxide semiconductor channel layer is exposed between the source and the drain.

1. Field of the Invention
The invention generally relates to a semiconductor device, and more particularly, to an active device.
2. Description of Related Art
The most popular liquid crystal display (LCD) today is composed of a thin film transistor (TFT) array substrate, a color filter substrate and a liquid crystal layer between the above-mentioned two substrates. On a conventional TFT array substrate, it is mostly adopted that the amorphous silicon (a-Si) TFT or the low-temperature polysilicon TFT servers as a switching element of each sub-pixel. In recent years, some studies have pointed out that in comparison with an a-Si TFT, an oxide semiconductor TFT has higher field-effect mobility; and in comparison with a low-temperature polysilicon TFT, an oxide semiconductor TFT has better threshold-voltage uniformity (Vth uniformity). As a result, the oxide semiconductor TFT has the potential to become a key element for the next generation's planar displays. However, under its existing architecture, the conventional oxide semiconductor TFT is not easy to further enhance field-effect mobility.


A data processing apparatus 2 is provided which is responsive to data access instructions to perform data access operations. These data access instructions have a first form utilising a 12-bit offset field but with a fixed addressing mode and a second form utilising a shorter 8-bit offset field but with an addressing mode specified within a manipulation mode control field of the data access instruction.

1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to the encoding of data access program instructions for use in data processing systems.
2. Description of the Prior Art
It is known to provide data processing systems with data access instructions. An example of such a class of program instructions is the LDR/LDRB/STR/STRB class of instructions of the ARM instruction set (see for example the ARM Architecture Reference Manual). These are a group of instructions that are orthogonally encoded with respect to each other, in the sense that they specify different main operations, but each main operation can use the same addressing modes or other sub-operations as all the others. The ARM instruction set is a 32-bit instruction set and the LDR/LDRB/STR/STRB class of instructions contains 20 bits that affect the addressing mode calculation:
4 bits (bits[19:16]) to specify the base register;
13 bits (bit[25] and bits[11:0]) to specify either a 12-bit immediate offset (a first form of the instruction) or an index register and a shift (or rotate) to be applied to it (a second form of the instruction); and
3 bits (P=bit[24], U=bit[23], W=bit[21]) to specify the manipulation to be performed on the base register value and the offset.
Examples of the addressing modes that may be specified are offset addressing, pre-indexed addressing, post-indexed addressing and unprivileged post-indexed addressing. Such data access instructions provide considerable flexibility in the way that the data access operation may be specified. This helps to reduce the number of instructions required to transfer the desired data to or from memory thereby increasing speed and improving code density.
A common problem within data processing systems is that the encoding bit space available is a finite resource and competing demands are made upon this encoding bit space for different types of instructions which may be useful in different circumstances. It is often the case that the number of potentially useful instructions that might be provided exceeds the encoding bit space available within the processor architecture. Accordingly, measures which can improve the efficiency of use of the encoding bit space are strongly advantageous.

Data access program instruction encoding


A turbine blade with a spar and shell construction in which the spar includes a blade tip and a dove-tail on the root end of the spar. A pair of platform halves form a fir-tree attachment capable of sliding into an attachment slot formed within a rotor disk. The platform halves form a slot within the fir-tree configuration that will pinch the dovetail slot of the spar and secure the spar to the platform halves against radial displacement. The shell is secured between the spar tip and the platform of the platform halves when assembled together. The spar includes cooling air passages and impingement cooling holes to provide backside impingement cooling of the shell. A fastener secures the two platform halves together so that the spar and shell blade assembly can slide into the attachment slot within the rotor disk.

1. Field of the Invention
The present invention relates generally to fluid reaction surfaces, and more specifically to a turbine blade with a spar and shell construction.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
In a gas turbine engine, such as an aero engine used to power an aircraft or an industrial gas turbine engine used to produce electrical power, a turbine section includes a plurality of stages of rotor blades and stator vanes to extract the energy from the hot gas flow passing through. The engine efficiency can be improved by increasing the temperature of the hot gas flow entering the turbine. However, the inlet temperature is limited to the material properties of the first stage vanes and rotor blades. To improve the efficiency, a complex internal cooling circuits have also been proposed to provide impingement and film cooling to these airfoils in order to allow for a higher gas flow temperature.
A recent improvement in the high temperature resistant airfoils is the use of a spar and shell construction in which a shell having the shape of the airfoil is secured to a spar for support. The shell is typically made from a material that cannot be cast or forged like the nickel based super-alloys used to make turbine blades and vanes. The shell is fabricated from exotic high temperature materials such as Niobium or Molybdenum or their alloys in which the airfoil shape is formed by a well known electric discharge machining process (EDM) or a wire EDM process that can make a thin wall shell suitable for near wall impingement cooling in an airfoil. Because the turbine blade would be under high centrifugal forces during operation, the shell could even be made from a ceramic material because the spar would support the load, allowing for the shell to be exposed to the high temperature gas flow.
Turbine rotor disks also include blade attachment slots in which a root of the turbine blade having a fir-tree configuration is inserted to secure the blade to the rotor disk in the radial direction. The single piece cast nickel super-alloy turbine blade includes the root portion with the fir-tree configuration to fit within the disk slot. There is a need in the prior art for a spar and shell constructed blade to be capable of replacing the nickel super-alloy blade by using the attachment slot within the rotor disk to insert the spar and shell constructed blade.
The Prior Art U.S. Pat. No. 4,790,721 issued to Morris et al on Dec. 13, 1988 and entitled BLADE ASSEMBLY discloses a turbine blade with a metal core having a cap or blade tip, a metal liner functioning as a coolant containing surface, and a ceramic blade jacket secured between the blade tip of the metal core and the platform of the base having the fir-tree configuration. The metal core that holds the ceramic blade jacket (the shell) is secured to the fir-tree base by bonding. This construction is considered to be very weak in holding the blade together during operating speeds producing high centrifugal forces that tend to pull the spar away from the fir-tree root or base. Also, this construction does not permit removal and replacement of the shell component, which is known to be the life limiting part of the spar and shell constructed blade.
It is an object of the present invention to provide for a turbine blade of the spar and shell construction that can be inserted into the dove-tail slot of the rotor disk.
It is another object of the present invention to provide for a turbine blade having a spar and shell construction that can withstand the high centrifugal forces during operation of the engine.
It is another object of the present invention to provide for a turbine blade of the spar and shell construction with a fir-tree root in which the shell can be easily replaced.

Turbine blade with spar and shell construction


The invention provides a semiconductor memory device which realizes high speed reading by automatically adjusting and optimizing charge and discharge timings even when a change in an operation environment such as a variation in an operation voltage, an operation temperature, a process parameter and so on occurs. First and second dummy bit lines are provided for a bit line, each having a wiring load twice the wiring load of the bit line. A first sense circuit sensing the voltage of the first dummy bit line is provided to control a charging time according to a first sense signal. A second sense circuit sensing the voltage of the second dummy bit line is further provided to control a discharging time according to a second sense signal. A sense amplifier sensing the voltage of the bit line is activated in response to the second sense signal.

1. Field of the Invention
The invention relates to a semiconductor memory device, particularly, a semiconductor memory device which reads out data stored in a memory cell transistor by charging a bit line connected to the memory cell transistor and then discharging the bit line according to the data stored in the memory cell transistor.
2. Description of the Related Art
Recently, the nonvolatile memory is used not only for consumer goods such as a mobile, a digital camera and the like but also for on-vehicle, aerial or medical equipments, an ID card and the like which require high reliability in data storage.
The EEPROM (Electronically Erasable and Programmable Read Only Memory) is known as a general nonvolatile memory. This stores binary or multivalued digital data depending on whether or not a predetermined charge amount is accumulated in a floating gate and reads the digital data by sensing the change of conduction of a channel according to this charge amount. This EEPROM includes a stacked gate type EEPROM having a structure where a floating gate and a control gate are sequentially stacked on a semiconductor substrate and a split gate type EEPROM having a structure where a floating gate and a control gate face a channel of a semiconductor substrate.
FIG. 3 is a cross-sectional view showing one memory cell transistor MT of the split gate type EEPROM. An n+-type drain 102 and an n+-type source 103 are formed on a front surface of a P-type semiconductor substrate 101 at a given distance from each other, and a channel 104 is formed therebetween. A floating gate 106 is formed on a portion of this channel 104 and a portion of this source 103 with a gate insulation film 105 being interposed therebetween. An insulation film 107 thicker than the gate insulation film 105 is formed on the floating gate 106.
A tunnel insulation film 108 is formed covering the side surface of the floating gate 106 and a portion of the upper surface of the thick insulation film 107. A control gate 109 is formed on the tunnel insulation film 108 and a portion of the channel 104.
The operation of the memory cell transistor MT having this structure is as follows. First, when data "0" is written, a predetermined voltage is applied to the control gate 109 and the source 103 (e.g. 0V to the P-type semiconductor substrate 101 and 2V to the control gate 109) and a high voltage (e.g. 10V) is applied to the source 103 to flow a current through the channel 104, and thereby channel hot electrons are injected into the floating gate 106 through the gate insulation film 105. The channel hot electrons injected into the floating gate 106 are held in the floating gate 106 as electric charge.
On the other hand, when the data "0" stored in the memory cell transistor MT is erased, the drain 102 and the source 103 are grounded and a predetermined high voltage (e.g. 13V) is applied to the control gate 109 to flow a Fowler-Nordheim tunneling current through the tunnel insulation film 108, and thereby electrons accumulated in the floating gate 106 are extracted to the control gate 109. By this erasing, the digital data stored in the memory cell transistor MT turns to "1".
When the data stored in the memory cell transistor MT is read out, a predetermined voltage is applied to the control gate 109 and the drain 102 (e.g. 3V to the control gate 109 and 1V to the drain 102). Then, a cell current Ic flows between the source and the drain according to the charge amount of electrons accumulated in the floating gate 106. When the data "0" is already written, the threshold of the memory cell transistor MT is high and thus the cell current Ic is usually about 0 μA. When the data "1" is already written, the threshold of the memory cell transistor MT is low and thus the cell current Ic is usually about 40 μA. The described technique is described in Japanese Patent Application Publication No. 2000-173278.
As a method of reading data, there are a current sensing method where data stored in a memory cell transistor is judged to be "0" or "1" by comparing a cell current Ic with a reference current Iref, and a voltage sensing method where data stored in a memory cell transistor is judged to be "0" or "1" by converting a cell current Ic into a voltage and comparing the voltage with a reference voltage Vref.
Hereafter, the structure of a read circuit with the voltage sensing method will be described referring to FIG. 4. A plurality of memory cell transistors shown in FIG. 3 is disposed into a matrix, forming a memory array 1. FIG. 4 shows only one memory cell transistor MT. The memory cell transistor MT is provided at an intersection of a bit line BL extending in the Y direction and a word line WL extending in the X direction, where a source 103 is connected to a source line SL extending in the X direction, a drain 102 is connected to the bit line BL, and a control gate 109 is connected to the word line WL.
A numeral 2 designates a sense amplifier comparing the voltage of the bit line BL and a reference voltage Vref (0<Vref<Vcc), which is activated by a sense enable signal SAENB from a read control circuit 3. A numeral 4 designates a precharge transistor precharging the bit line into H level (a supply voltage Vcc). The precharge transistor 4 is configured of a P-channel type MOS transistor, and a precharge enable signal PC from the read control circuit 3 is inputted to the gate thereof through an inverter 5.
The read control circuit 3 is configured of a circuit shown in FIG. 5 having a first delay circuit 31 delaying a read enable signal RDE, a second delay circuit 32 delaying the output of this first delay circuit 31, and an AND circuit 33 performing logical multiplication of the read enable signal RDE and an inverted signal of the output of the first delay circuit 31. Each of the first and second delay circuits 31 and 32 is configured of a resistor and a capacitor. The precharge enable signal PC is obtained from the output of the AND circuit 33, and the sense enable signal SAENB is obtained from the output of the second delay circuit 32.
The operation of this read circuit will be described referring to FIG. 6. When the word line WL turns to H level, the memory cell transistor MT is turned to a selected state. When the read enable signal RDE turns to H level, the precharge enable signal PC turns to H level and keeps it for a period t1. When the precharge enable signal PC turns to H level, the precharge transistor 4 turns on and the bit line BL is charged into H level.
Then, when a period t2 passes, the sense enable signal SAENB turns to H level and the sense amplifier 2 is activated. During this period t2, the data stored in the memory cell transistor MT is read out. In detail, the cell current Ic flows when the data stored in the memory cell transistor MT is "1", and the bit line BL is discharged into L level (a ground voltage Vss). In this case, the output of the sense amplifier 2 becomes L level. On the other hand, when the data stored in the memory cell transistor MT is "0", the cell current Ic hardly flows and thus the voltage of the bit line BL keeps H level. In this case, the output of the sense amplifier 2 becomes H level.
The period t1 is determined by the delay time of the first delay circuit 31, and the period t2 is determined by the delay time of the second delay circuit 32.
As described above, the bit line BL is charged and then discharged in the reading operation, and the periods t1 and t2 for charging and discharging (=the reading time) are set by the first delay circuit 31 and the second delay circuit 32, respectively. Therefore, in this read circuit, the periods t1 and t2 are set so that the reading operation can be performed in the worst operation environment taking account of variation in an operation voltage, an operation temperature, a process parameter and so on. This causes a problem that an unnecessary margin is required in the reading time under a condition which is not in the worst environment and thus a high speed reading operation is not achievable.

Semiconductor memory device with dummy bit lines for charge and discharge timing


A novel class of discotic liquid crystals represented by the following formula was synthesized, and a layer thereof was incorporated in an organic electroluminescence device.

The present invention relates to a novel discotic liquid crystal having a polyfluorinated side chain and a broad and stable liquid crystal phase and to an organic electroluminescence device using the discotic liquid crystal.
Discotic liquid crystal phase is a liquid crystal phase discovered in 1977 by Chandrasekhar, et al. (Pramana, 9, 471 (1977)). As described in their paper entitled xe2x80x9cDiscotic Liquid Crystalsxe2x80x9d (Rep. Prog. Phys., 53, 57 (1990)) and in a paper entitled xe2x80x9cDesign and Synthesis of Discotic Liquid Crystal Moleculesxe2x80x9d by Shunsuke Takenaka (Japanese Chemical Society, Seasonal Publication, General Review, vol. 22, pp. 60+), the discotic liquid crystal phase is found in compounds having a disk-shaped core and a plurality of relatively long chains connected to the core. Such compounds may be classified into various types according to their core structure, inclusive of derivatives of hexa-substituted benzene and tri-substituted benzene; derivatives of phthalocyanine and porphyrin; derivatives of triphenylene, truxene and pyrylium, respectively; tribenzocyclononene derivatives, azacrown derivatives, and cyclohexane derivatives.
Based on the structural characteristic of a discotic liquid crystal, several reports have been made suggesting application thereof to devices. A systems including conjugated xcfx80-electrons, as found in derivatives of phthalocyanine or triphenylene, can provide a channel for electrons (or holes) (Piechocki, et al., J. Am. Chem. Soc., 104, pp. 5245 (1982)). Further, a system including an annular core, as found in an aza-crown derivative, can provide a molecular channel using the central spacing thereof as a selective molecular passage (Lehn, et al., J. Chem. Soc., Chem. Commun., pp. 1794 (1985)).
On the other hand, since 1987 when T. W. Tang et al. proved that a high luminance light emission was achieved by a low voltage drive of a laminate of their films of a fluorescent metal chelate complex and a diamine molecule, extensive research has been made on organic electroluminescence devices (hereinafter, the term xe2x80x9celectroluminescencexe2x80x9d is sometimes abbreviated as xe2x80x9cELxe2x80x9d according to a common usage in the field) as luminescence or light emission devices having a high speed responsiveness and a high efficiency. An organic EL device is a carrier injection-type self-light emission device utilizing luminescence caused at the time of recombination of electrons and holes having reached the luminescence layer.
FIGS. 2 and 3 respectively illustrate a laminate structure of an ordinary organic EL device. Referring to FIG. 2 (or FIG. 3), an EL device includes a cathode metal electrode 21 (or 31) and an anode transparent electrode 24 (or 35) disposed on a transparent substrate 25 (or 36) for taking out luminescent light. Organic compound layers, each having a thickness on the order of several hundred xc3x85 (angstoms), are sandwiched between the electrodes. The cathode may generally comprise a metal having a small work function, such as aluminum, aluminum-lithium alloy, magnesium-silver alloy, etc. The anode may comprise a conductive material having a large work function, such as indium tin oxide (ITO). The organic compound layers, may ordinarily have a two layer structure including a luminescence layer 22 and a hole-transporting layer 23 as shown in FIG. 2 or a three layer structure including an electron-transporting layer 32, a luminescence layer 33 and a hole-transporting layer 34 as shown in FIG. 3.
The hole-transporting layer has a function of effectively injecting holes from the anode into the luminescence layer, and the electron-transporting layer has a function of effectively injecting electrons from the cathode into the luminescence layer. The hole-transporting layer also has a function of confining electrons, and the electron-transporting layer also has a function of confining holes, respectively, into the luminescence layer, i.e., carrier-blocking functions for enhancing the luminescence efficiency. For these carrier-transporting layers, inclusive of the hole-transporting layer and the electron-transporting layer, a charge-transporting performance, particularly a carrier mobility, may be regarded as an important property. An organic compound in an amorphous state may generally exhibit a carrier mobility on the order of 10xe2x88x925 cm2/V.sec, which cannot be said to represent a sufficient transporting performance. It is believed that if the mobility of a carrier-transporting layer is increased, a larger amount of carrier can be injected into the luminescence layer to enhance the luminescence efficiency, and simultaneously the thickness of the carrier-transporting layer (generally having a thickness on the order of several hundred xc3x85) can be increased (to a thickness up to ca. 1 xcexcm), so that it becomes possible to effectively prevent a short circuit between the electrodes sandwiching the organic layers and provide an improved productivity.
At present, in order to achieve a higher efficiency organic EL device, extensive work toward the development of various compound materials for the carrier-transporting layers has been made. Along with the activity, some proposal has been made to achieve a higher mobility by imparting mesomorphism to organic compounds forming carrier-transporting layers. Organic films generally used in organic EL devices are in an amorphous state and have no regularity regarding molecular alignment. In contrast thereto, some organic compounds in a liquid crystal state, i.e., having some order of molecular alignment, have been found to show a high mobility, thus calling attention.
For example, Haarer, et al. observed that a long chain triphenylene compound, a representative discotic liquid crystal material, exhibited a high hole mobility of 10xe2x88x921 cm2/V.sec (Nature, vol. 371, p. 141 (1994)). Further, Haarer, et al. examined a relationship between hole mobility and molecular alignment order in columnar phase for a series of triphenylene-type discotic liquid crystals and reported that a higher order provided a higher mobility (Adv. Mater., vol. 8, p. 815 (1996)). Thus, a molecular alignment control advantageous for carrier transportation is expected to be achieved by utilizing spontaneous alignment of mesomorphic organic compounds, thus providing excellent carrier-transporting materials. On the other hand, organic EL devices involve problems regarding durability, such as deterioration of luminescence performance due to moisture and due to reaction between organic compound layers.
Some discotic liquid crystal compounds having polyfluorinated side chains have been reported in Liquid Crystal, vol. 19, No. 6, pp. 759-764 (1995). More specifically, three species of triphenylene derivatives (5a, 5b and 5c), each having 6 polyfluorinated side chains, are shown in FIG. 2 at page 760 of the above report. These compounds have an intermediate carboxyl group in their side chains and do not cause transformation from the discotic columnar phase to clarifying point (Iso), but reach a decomposition point on temperature increase as shown in a table at an upper left portion of page 761, so that they cannot be regarded as stable discotic liquid crystal compounds.
A generic object of the present invention is to solve the above-mentioned problems of the prior art.
A more specific object of the present invention is to provide a novel discotic liquid crystal compound having a stable and broad discotic liquid crystal phase.
Another object of the present invention is to provide an organic electroluminescence device exhibiting stable and good luminescence performance by using the liquid crystal compound.
According to the present invention, there is provided a discotic liquid crystal compound represented by formula (1) below:
Ar"Parenopenst"Xxe2x80x94R)nxe2x80x83xe2x80x83(1),
wherein Ar denotes a group of 2,3,5,6-benzoquinone-tetra-yl, 2,3,4,6,7,8-anthraquinone-hexa-yl, 2,3,6,7,10,1 1-triphenylene-hexa-yl, 2,3,7,8,12,13-truxene-hexa-yl, 2,3,6,7,10,11-tricycloquinazoline-hexa-yl, or 1,2,5,6,8,9,12,1 3-dibenzopyrene-octa-yl; X denotes a single bond, an oxygen atom, a sulfur atom, xe2x80x94OOCxe2x80x94 or xe2x80x94COOxe2x80x94; R denotes a linear or branched alkyl group having 3-20 carbon atoms, of which at least 2 hydrogen atoms have been replaced with fluorine atoms and of which one methylene group can be replaced with an oxygen atom, a sulfur atom, xe2x80x94CHxe2x95x90CHxe2x80x94 or xe2x80x94Cxe2x89xa1Cxe2x80x94; and n is an integer of 4, 6 or 8 corresponding to a valence of the group Ar. The discotic liquid crystal of the present invention is essentially different from the above-mentioned discotic liquid crystal compounds disclosed in Liquid Crystal having polyfluorinated side chains that include intermediate carboxyl (i.e., ester) groups.
The present invention further provides an organic electroluminescence device including a layer comprising the discotic liquid crystal of the present invention.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.

Discotic liquid crystal and organic electroluminescence device using same


Disclosed are a method and apparatus for inspecting a wafer for electrical defects. A first electron beam is irradiated onto an area of the wafer including an inspection region to charge the area. A second electron beam is irradiated onto the inspection region to inspect the inspection region after focusing the second electron beam on the inspection region. A third electron beam is irradiated onto the area to discharge charges accumulated on the area. Therefore, the electrical defect of the wafer can be precisely detected with increased voltage contrasts for distinguishing the electrical defect. This method and apparatus have improved detection sensitivity and detection reliability over conventional methods.

1. Field of the Invention
The present invention relates to a method and an apparatus for inspecting a wafer. More particularly, the present invention relates to a method for inspecting a wafer for electrical defects of a semiconductor device formed on the wafer using electron beams and an apparatus for performing the same.
2. Description of the Related Art
Generally, semiconductor devices are fabricated by performing a series of unit processes to a wafer. When the unit processes for manufacturing the semiconductor devices are performed, defects that cause failures of the semiconductor devices can be generated on a wafer. These defects are generally divided into physical defects, like contaminant particles and electrical defects, which cause faulty operation or electrical deterioration of the semiconductor devices. For example, electrical defects can include problems such as a contact that is not opened or a contact with an increased resistance.
Wafers are usually analyzed with electron beams to find electrical defects. In a method for analyzing wafers for electrical defects using electron beams, the electron beams are primarily irradiated onto a surface of a predetermined inspection region of a wafer. The surface of the wafer is charged instantly, and secondary electrons are then emitted from the wafer surface. The secondary electrons are detected and electrical defects on the wafer can then be analyzed by contrasting the voltages of the secondary electrons.
U.S. Pat. No. 6,091,249 (issued to Talbot et al.) discloses a method for analyzing a defect of a wafer using electron beams. According to the disclosure in U.S. Pat. No. 6,091,249, the process for analyzing wafers for defects is performed by instantly charging a pre-determined surface of a region of the wafer. However, when the surface of the wafer has been charged insufficiently, a sufficient voltage contrast generated from a defective region may not be obtained. As a result, an electrical defect generated on the surface of the wafer may not be detected.
After the analysis of the first region of the surface of the wafer is finished, another region of the wafer surface is then analyzed. When this second region of the wafer is adjacent to the first analyzed region of the wafer, which is common for ease of analysis, a section of the second region can overlap the first region. Because the first region has already been inspected and now has a charge, the overlapping section in the second region will have different charge characteristics from the rest of the second region. These different conditions can interfere with the detection process in the second region. This in turn can reduce the detection sensitivity and detection reliability of the testing apparatus.

Method for inspecting a wafer and apparatus for inspecting a wafer


A drum type washing and drying machine has a water tank (4), a rotary drum rotatably provided in the water tank (5), a dehumidifying heat exchanger for dehumidifying air introduced from inside of the rotary drum (5), a heater unit for heating the air dehumidified by the dehumidifying heat exchanger, and a blower (131) for introducing the air in the rotary drum (5) into the dehumidifying heat exchanger and delivering into the rotary drum (5) the air heated by the heater unit. A filter (160) is placed in a suction-side channel between the rotary drum (5) and the blower and on an upstream side of air flow produced by the blower (131) in a drying process. The filter (160) is placed so as to be soaked in water supplied into the water tank in a washing process or in a rinsing process.

FIG. 1 shows a schematic cross-section of a conventional drum type washing and drying machine (see JP 2001-149689 A, for example).
The drum type washing and drying machine includes an outer casing 1, a water tank 4 placed in the outer casing 1, a rotary drum 5 placed in the water tank 4 and intended for accommodating a wash, a transparent inflexible outside door 3, an automatic door opening/shutting mechanism 10, and a dryer unit 24 for drying the wash.
On a front face of the outer casing 1 is formed an outer casing opening 1a. A wash is put in and taken out through the outer casing opening 1a. The outer casing opening 1a is opened and shut by the outside door 3 that is slidable upward and downward with respect to the outer casing 1. On upper part of the front face of the outer casing 1 is provided an operation panel 11 having operation keys, display units, and the like. A control unit 2 for controlling operation of the drum type washing and drying machine is provided on reverse side of the operation panel 11 (on a side of the water tank 4), and thus input into the operation panel 11 allows successive or separate performance of a washing process, a rinsing process, a dewatering process, and a drying process. The outer casing 1 elastically supports the water tank 4 through medium of a suspension 8 as an example of an elastic support unit.
The water tank 4 has a shape of a bottomed cylinder with a water tank opening 4a that opens in face of the outer casing opening 1a, and is positioned transversely and slantly so that rear side thereof (bottom side of the water tank 4) is in lower position. The water tank opening 4a and the outer casing opening 1a face each other with a space between. A transparent lid body 6 is mounted on the water tank with use of hinge mechanism, so that the water tank opening 4a can be opened and shut by the lid body. On the lid body 6 is formed convex part 6a that protrudes toward inside of the rotary drum 5 when the opening 4a of the water tank 4 is shut. A sealing member 41 is provided on inner circumferential surface part of the water tank opening 4a and, while the water tank opening 4a is shut by the lid body 6, the water tank opening 4a is held watertight by intimate contact between the sealing member 41 and the convex part 6a.
The rotary drum 5 has a shape of a bottomed cylinder with a drum opening 5c that opens in face of the water tank opening 4a, and is positioned transversely and slantly so that rear side thereof (bottom side of the rotary drum 5) is in lower position. A motor 9 is connected to backside of the rotary drum 5 through a shaft 5e, and drives the rotary drum 5 to rotate in accordance with control by the control unit 2. A plurality of small bores 5a are formed on a whole area of a circumferential wall of the rotary drum 5. The small bores 5a allow circulation of washing water (water such as tap water and bath water or water containing detergent or the like), dry air or the like between a space between the water tank 4 and the rotary drum 5 and a space in the rotary drum 5. On an inner wall surface of the rotary drum 5 are provided baffles 5b protruding inward in radial directions. The baffles 5b are provided circumferentially at three sites at intervals of 120°, for example, and repeatedly lift up and drop the wash with rotation of the rotary drum 5. When the rotary drum 5 is rotating, a fluid balancer 5d that surrounds the drum opening 5c from outside reduces unbalance caused by one-sided wash and washing water, through agency of motions of fluid sealed in the fluid balancer 5d.
The dryer unit 24, which has a blower 31 and a heater unit 32, is provided on top of the water tank 4. In the dryer unit 24, the blower 31 is positioned on rear side and the heater unit 32 is positioned on front side with respect to front and rear of the drum type washing and drying machine. The blower 31 includes blower blades 34 in a casing 33 and a fan motor 35 for driving the blower blades 34 to rotate, which motor is provided outside the casing 33. The fan motor 35 is directly connected to the blower blades 34 so as to drive the blower blades 34 to rotate with use of a direct drive structure. On the other hand, the heater unit 32 includes a heater 36 in a heater case 26, and inlet part of the heater case 26 communicates with outlet part of the casing 33 of the blower 31.
At bottom of the water tank 4 is provided a drain valve 20 that is opened/shut by a drain valve motor not shown. Upon opening of the drain valve 20, water in the water tank 4 is drained through a flexible drain hose 19 to outside.
In the outer casing 1, a blower duct 38 is placed on front side of the water tank 4. One end of the blower duct 38 communicates with outlet part of the heater case 26, and the other end of the blower duct 38 forms a jet 38a communicating with inside of the water tank 4 and inside of the drum opening 5c in peripheral part of the water tank opening 4a. That is, the blower duct 38 and the jet 38a act as a blower unit for supplying heated air toward inside of the rotary drum 5 through the water tank opening 5c.
In addition, a dehumidifier 27 is provided on back side of the water tank 4 in the outer casing 1. With water poured into the dehumidifier 27 through upper part thereof, the dehumidifier 27 performs dehumidification by cooling and condensing water content in air that passes therethrough. The dehumidifier 27, which is hollow as a whole, has a water inlet 27a and an air outlet 27b in the upper part and has an air inlet 27c doubling as a water outlet in lower part thereof. The air outlet 27b of the dehumidifier 27 communicates with inlet part of the casing 33 of the blower 31, and the air inlet 27c communicates with lower part of inside of the water tank 4. To the water inlet 27a is connected a feed water supply system not shown.
In accordance with the drum type washing and drying machine having the above configuration, a user opens the lid body 6 directly and manually, thereafter puts a wash into the rotary drum 5 through the outer casing opening 1a, and then shuts the lid body 6 directly and manually. Thus inner rim 41a of the sealing member 41 is brought into intimate contact with rim of the lid body 6 so that the water tank 4 is sealed. When the user manipulates the operation panel 11 so that a washing operation is started on basis of an instruction from the control unit 2, the automatic door opening/shutting mechanism 10 initially slides the outside door 3 in an upward direction in the drawing along a front panel 7. Then the outside door 3 shuts the outer casing opening 1a, as shown in FIG. 2, while making a track generally shaped like an arc. Upon termination of the washing operation, subsequently, the automatic door opening/shutting mechanism 10 slides the outside door 3 in a downward direction in the drawing along the front panel 7. Thus the outer casing opening 1a is opened again as shown in FIG. 1. After that, the user opens the lid body 6 directly and manually and subsequently takes the wash out of the rotary drum 5.
In a drying operation, the blower 31 is driven to rotate while the heater 36 is energized for heating. Thus air supplied by the blower 31 is heated by the heater 36 while passing through the heater case 26, and the air having got a high temperature is forwarded through the blower duct 38, the jet 38a, and the water tank opening 5c toward the wash in the rotary drum 5, so as to dry the wash. The hot humid air having absorbed moisture of the wash in the rotary drum 5 is exhaled, from the small bores 5a formed on a circumferential surface of the rotary drum 5, into the space between the rotary drum 5 and the water tank 4. The space between the rotary drum 5 and the water tank 4 communicates with a space around the dehumidifier 27, as described above, and the air flowing around the dehumidifier 27 comes into contact with a wall of the dehumidifier 27 cooled by cold water flowing through the dehumidifier 27, then forms dew, and thereby undergoes dehumidification. The dehumidified air is forwarded afresh by the blower 31 via the heater 36 into the rotary drum 5. In this manner, the process of drying the wash in the rotary drum 5 is carried out. Such a drum type washing and drying machine is disclosed in JP 2001-149689 A, for example.
In the drying process in the drum type washing and drying machine, however, the action of lifting up a wash by the baffles 5b and thereafter dropping the wash is repeated with the rotary drum 5 rotated at a low speed and, in progress of the drying process, minute dust such as lint, fluff, or fuzz appears from the dried wash. Such minute dust may enter into the casing 33 with the air circulation caused by the dryer unit 24.
In the washing process or the rinsing process, normally, such foreign matter as lint in washing water is removed by a filter unit or the like (not shown) provided before the drain valve 20; in the drying process, however, such foreign matter circulating with air passing through the dryer unit 24 is not removed and may adhere to a shaft linking the blower blades 34 to the fan motor 35 and may form a resistance against the rotation of the blower blades 34 and the shaft, which resistance may degrade blowing capacity of the blower 31 with long-term use thereof.


The invention provides a method for determining the presence of leptin in a sample.

Obesity, defined as an excess of body fat relative to lean body mass, is associated with important psychological and medical morbidities, the latter including hypertension, elevated blood lipids, and Type II or non-insulin-dependent diabetes mellitus (NIDDM). There are 6-10 million individuals with NIDDM in the U.S., including 18% of the population of 65 years of age (Kamel, H K, et al, Clin. Geriatr. Med., 1999, 15, 265). Approximately 45% of males and 70% of females with NIDDM are obese, and their diabetes is substantially improved or eliminated by weight reduction (Harris 1991, Diabetes Care, 14, 639).
Leptin, the product of the obese gene (Zhang, Y., et al. 1994, Nature 372, 425) functions as a peripheral signal to the brain that regulates food intake and energy metabolism. Leptin is thought to exert its action in the hypothalamus through its receptor, OB-R (Tartaglia, L. A., et al, 1995, Cell 83, 1263). Rodents with mutations that prevent normal expression of either leptin or full-length OB-R are profoundly obese, diabetic, and have a reduced metabolic rate (Coleman, D. L. 1978, Diabetologia 14, 141). However, human obesity does not appear to be associated with mutations in the genes encoding leptin or OB-R (Considine, R. V., et al. 1995, J. Clin. Invest. 95, 2986; Considine, R. V., et al, 1996, Diabetes 19, 992). Although mice with a mutant obese gene can be returned to normal weight by administration of recombinant leptin (Pelleymounter, M. A., et al. 1995, Science 269, 540; Halaas, J. L., et al, 1995, Science 269, 543; Campfield, L. A., et al, Science 269, 546), it seems unlikely that this approach will succeed in obese humans because their serum leptin levels are chronically elevated (Maffei, M., et al, 1995, Nature Med. 1, 1155; Considine, R. V., et al, 1996, N. Engl. J. Med. 334, 292; Sinha, M. K., et al, 1996, J. Clin. Invest. 98, 1277). Obese humans, therefore, appear to be "leptin resistant" (Maffei, M., et al, 1995, Nature Med. 1, 1155; Flier, J. S. & Elmquist, J. K. 1997, Nature Biotech. 15, 20; Campfield, L. A., et al, 1996, Horm. Metab. Res. 28, 619) in that they do not generate a signal commensurate with their serum leptin levels, perhaps because of defective transport of leptin across the blood-brain barrier (Caro, J. F., et al, 1996, Lancet 348, 159) or an inadequate OB-R response. Analysis of OB-R signaling pathways may reveal alternative therapeutic approaches of boosting OB-R responses to overcome leptin resistance and reverse obesity. Leptin and OB-R are members of the four-helical bundle cytokine and receptor superfamilies respectively (Tartaglia, L. A., et al, 1995, Cell 83, 1263; Madej, T., et al, 1995, FEBS Lett. 373, 13). OB-R is most closely related to the gp130 signal transducing receptor that is activated by cytokines such as Interleukin-6 and CNTF, whose signaling pathways have been intensively studied (Kishimoto, T., et al, 1992, Science 258, 593; Stahl, N. & Yancopoulos, G. D. 1994, J. Neurobiology 25, 1454). Leptin receptors are translated as several alternatively spliced products with different cytoplasmic domains (Tartaglia, L. A., et al, 1995, Cell 83, 1263; Lee, G.-H., et al, 1996, Nature 379, 632; Chen, H., et al, 1996, Cell 84, 491; Cioffi, J. A., et al, 1996, Nature Med. 2, 585; Wang, M. Y., et al, 1996, FEBS Lett. 392, 87), but only one isoform, known as the long form or OB-Rb, appears capable of mediating leptin's weight controlling effects (Lee, G.-H., et al, 1996, Nature 379, 632; Chen, H., et al, 1996, Cell 84, 491; Ghilardi, N., et al, 1996, Proc. Natl. Acad. Sci. USA 93, 6231; Baumann, H., et al, 1996, Proc. Natl. Acad. Sci. USA 93, 8374). Obese diabetic (db) mice have a mutation in OB-R that prevents expression of the long OB-R splice isoform, which renders them incapable of appropriately mediating leptin's actions (Lee, G.-H., et al, 1996, Nature 379, 632; Chen, H., et al, 1996, Cell 84, 491).
The discovery of new biologically active molecules, which are used as drugs for the treatment of life-threatening diseases, has involved two basic operations: (i) a more or less random choice of a molecular candidate, prepared either via chemical synthesis or isolated from natural sources, and (ii) the testing of the molecular candidate for the property or properties of interest. The discovery cycle is repeated indefinitely until a molecule possessing the desirable properties is located. In the majority of cases, the molecular types chosen for testing have belonged to rather narrowly defined chemical classes. For example, the discovery of new peptide hormones has involved work with peptides; the discovery of new therapeutic steroids has involved work with the steroid nucleus. As a result, the discovery of new functional molecules, being ad hoc in nature and relying predominantly on serendipity, has been an extremely time-consuming, laborious, unpredictable, and costly enterprise.
Modern theories of biological activity state that biological activities, and therefore physiological states, are the results of molecular recognition events. For example, nucleotides can form complementary base pairs so that complementary single-stranded molecules hybridize, resulting in double- or triple-helical structures that appear to be involved in regulation of gene expression. In another example, a biologically active molecule, referred to as a ligand, binds with another molecule, usually a macromolecule referred to as ligand-acceptor (e.g. a receptor or an enzyme), and this binding elicits a chain of molecular events which ultimately gives rise to a physiological state, e.g. normal cell growth and differentiation, abnormal cell growth leading to carcinogenesis, blood pressure regulation, nerve-impulse-generation and propagation, etc. The binding between ligand and ligand-acceptor is geometrically characteristic and extraordinarily specific, involving appropriate three-dimensional structural arrangements and chemical interactions.
A currently favored strategy for development of agents which can be used to treat diseases involves the discovery of forms of ligands of biological receptors, enzymes, or related macromolecules, which mimic such ligands and either boost (i.e., agonize) or suppress (i.e., antagonize) the activity elicited by the acceptor or receptor. The discovery of such desirable ligands has traditionally been carried out either by random screening of molecules (produced through chemical synthesis or isolated from natural sources, for example, see K. Nakanishi, Acta Pharm. Nord., 1992, 4, 319-328.), or by using so-called "rational" approach involving identification of lead-structure, usually the structure of the native ligand, and optimization of its properties through numerous cycles of structural redesign and biological testing (for example see Testa, B. & Kier, L. B. Med. Res. Rev. 1991, 11, 3548 and Rotstein, S. H. & Mureko, M. A., J. Med. Chem. 1993, 36, 1700). Since most useful drugs have been discovered not through the "rational" approach but through the screening of randomly chosen compounds, a hybrid approach to drug discovery has recently emerged which is based on the use of combinatorial chemistry to construct huge libraries of randomly-built chemical structures which are screened for specific biological activities. (Brenner, S. & Lerner, R. A. Proc. Natl. Acad. Sci. USA 1992, 89, 5381). Any screen of such huge libraries of randomly built chemical structures requires a cost-effective biological assay that is amenable to automation.
Leptin is traditionally assayed in vivo by injecting it to ob/ob mice and observing their reduction in body mass. This bioassay is cumbersome, takes a long time and not reproducible. It is also not suitable for e.g. high throughput screening of libraries containing millions of compounds. Yet, some simpler assay systems were described. For example, the finding that the long form of OB-R contains the sequence YXXQ (Tartaglia, L. A., et al, (1995) Cell 83, 1263), which is a motif that specifies STAT3 activation (Stahl, N., et al, (1995) Science 267, 1349), raised the possibility that STAT3 is critical for mediating leptin responses. Recent results verify that STAT3 is activated both in cultured cells (Ghilardi, N., et al, (1996) Proc. Natl. Acad. Sci. USA 93, 6931; Baumann, H., et al, (1996) Proc. Natl. Acad. Sci. USA 93, 8374; Rosenblum, C. I., et al, (1996) Endocrinology 137, 5178) and in vivo (Vaisse, C., et al, (1996) Nature Gen. 14, 95) by the long form of OB-R, and not by a truncated OB-R or the long form of OB-R with a mutant YXXQ motif (Baumann, H., et al, (1996) Proc. Natl. Acad. Sci. USA 93, 8374; White, D. W., et al, (1997) J. Biol. Chem. 272, 4065). PCT patent application No. WO9857177 proposes the use of STAT3 activation as a basis for a simple in vitro leptin bioassay. However, STAT3 is activated by many other hormones and cytokines, including IL-6, CNTF, interferon alpha and beta, growth hormone and many more cytokines and polypeptide hormones. Therefore, activation of STAT3 can not be used as a specific marker of leptin activity.
PCT application WO9740380 discloses the use of a DNA cassette termed "leptin response element". Attachment of this DNA cassette to a promoter such as the thymidine kinase promoter and a reporter gene such as luciferase will provide a suitable reporter vector. Cells expressing the leptin receptor OB-Rb are transfected with the reporter vector. Such cells are proposed as tools for assay in vitro of leptin. However, according to PCT application WO9740380 the proposed "leptin response element" is identical with the "gamma activation sequence", a well-known element that is activated by many other cytokines, and particularly interferon gamma, interferon alpha and interferon beta. Therefore, assays based on the gamma activation sequence will not be able to discriminate between leptin-mimetic activity and e.g., interferon-mimetic activity.
Still another in vitro assay is based on a chimeric receptor consisting of the extracellular domain of OB-R fused to a transmembrane domain and an intracellular domain of a reporter receptor such as the IL-3 receptor. It is shown that IL-3-dependent cells expressing said chimeric receptor can be used for measuring leptin, which promotes cell proliferation. Thus, upon exposure to leptin, said cells will proliferate and their proliferation may be determined by MTT staining or by incorporation of radiolabelled thymidine (Verploegen S A, et al, 1997, FEBS Lett. 405, 237). This assay system is reliable, it is useful for measuring leptin and is amenable to high throughput screening. However, molecules selected by this high throughput screening based on this assay may not be leptin-mimetic at all. It was shown for instance that a true insulin mimetic agent, found by a high throughput screen acts by interacting with the cytoplasmic domain of the insulin receptor (Zhang B., et al, 1999, Science 284, 974). Therefore, there is a risk that molecules selected by chimeric receptors such as said leptin-IL-3 receptor chimera will interact with the cytoplasmic IL-3-derived domain of the chimera and therefore will be IL-3 mimetic rather than being leptin mimetic. Hence this assay is not reliable for screening of leptin-mimetic agents.
Leptin, the product of the obese gene is expressed in adipocytes and it regulates food intake and energy metabolism through its hypothalamic receptor OB-Rb. Lack of leptin, as in the case of ob/ob mice or lack of OB-Rb, as in the case of db/db mice leads to morbid obesity. However, the most common cases of human obesity are not associated with leptin deficiency. In fact, serum leptin correlates with body mass index and therefore obese individuals have high levels of serum leptin. This correlation led to the notion that obesity is associated with some form of leptin resistance. One possible mechanism of leptin resistance is the inefficient transfer of leptin through the blood brain barrier. Indeed, intracerebroventricular administration of leptin was significantly more effective in reducing adipose tissue mass of rodents as compared with peripheral routes of leptin administration.
Development of leptin-mimetic agents that may cross the blood brain barrier may solve the problem of leptin resistance. For this purpose it is advantageous to screen libraries consisting of low molecular weight agents in order to identify individual agents that exhibit leptin-mimetic activity. Such a screen requires a simple and specific bioassay of leptin activity. So far, as described above, the biological activity of leptin could be determined only by assay in animals. Such assays are cumbersome and therefore not suitable for screening libraries consisting of millions of different substances. Several in vitro assays were described but they are not specific for leptin. Therefore, there is a need to establish a simple and specific assay of leptin's activity that will be easily amenable to automation.


A high pressure synthetic gas stream is produced by gasifying coal. Hydrogen sulfide is removed by contacting the high pressure gas stream with a physical solvent, such as an alcohol, in an absorber column. A low temperature is maintained in the absorber column, typically by chilling both the solvent and the incoming high pressure synthetic gas stream, where a portion of the cooling requirement is supplied by adiabatically expanding the cleaned high pressure gas stream exiting the absorber. Typically, the cleaned high pressure gas stream will be expanded in a turbine expander to provide mechanical energy in addition to cooling capacity. The cleaned synthetic gas is useful as a fuel or chemical feedstock.

1. Field of the Invention
The present invention relates generally to methods for low temperature solvent absorption of acid gases from high pressure gas streams. More particularly, the present invention relates to a method for expanding a cleaned synthetic gas stream to provide at least a portion of the cooling requirement for the low temperature solvent absorption.
Synthetic gas streams produced by coal gasification are usually contaminated with sulfur, typically in the form of hydrogen sulfide, carbonyl sulfide, and the like. Before the synthetic gas can be used as a fuel for combustion or as a feed stock for chemical synthesis, it is usually necessary to remove such sulfur species to low levels.
Various processes are used for sulfur removal, including absorption processes which rely on contacting the synthetic gas stream with a physical or chemical solvent under conditions which promote absorption. Of particular interest to the present invention, physical solvents, such as lower monohydric alcohols, e.g. methanol, and polyhydric alcohols, e.g. ethylene glycol, may be contacted with the synthetic gas streams at low temperatures to effect the absorption of hydrogen sulfide. Such low temperature physical solvent absorption processes are commercialized under the tradenames Selexol (DMPEG), Ucarsol, Rectisol (low temperature), Purisol (NMP), and Fluor Solvent (propylene carbonate).
Low temperature solvent absorption of acid gas may be achieved in a conventional contactor, such as a tray or packed column, where the inlet solvent and/or the inlet synthetic gas are chilled and the column is insulated. Chilling of the solvent and/or inlet gas has usually been accomplished by direct or indirect heat exchange with a refrigerant which has been cooled in external refrigeration equipment. Although effective, the need to use external refrigeration equipment requires substantial energy and reduces the overall energy efficiency of the solvent absorption process.
It would therefore be desirable to provide a low temperature solvent acid gas absorption process having improved energy efficiency. In particular, it would be desirable to provide such low temperature acid gas absorption processes having a reduced requirement for external refrigeration. Even more particularly, it would be desirable to arrange the absorption process to employ energy available from the treated gas itself to provide for at least a portion of the necessary refrigeration requirement. Additionally, it would be desirable to arrange the absorption process to allow extraction of mechanical energy from the treated gas, where such mechanical energy can be used for producing electricity or other purposes.
2. Description of the Background Art
U.S. Pat. No. 4,019,314, discloses a coal gasifier which produces a synthetic gas which is fed to a scrubber-cooler. The scrubbed synthetic gas is fed to an expansion turbine, where mechanical energy is extracted. U.S. Pat. No. 4,524,581, describes a high pressure coal gasification process. U.S. Pat. No. 4,212,160 describes acid gas removal processes in combination with coal gasification. U.S. Pat. Nos. 4,211,540 and 4,155,988, describe the use of low temperature physical solvents for absorbing hydrogen sulfide from synthetic gases produced by coal gasification. None of the processes described in these patents disclose the expansion of gas with gas treating to reduce refrigeration requirements and increase efficiency.

Efficient low temperature solvent removal of acid gases


A digital camera includes a CCD imager. In a successive picture-taking mode, each time a subject is taken by the CCD imager, a corresponding main image signal is compressed by a JPEG CODEC. The compressed main image signals produced upon each picture taking are accumulated in a SDRAM. A compression process of thumbnail image signals is performed after completing successive picture taking by the CCD imager. That is, each of the compressed main image signals secured in the SDRAM is decompressed by the JPEG CODEC, a thumbnail image signal is produced on the basis of a decompressed image signal so that a produced thumbnail image signal is compressed by the JPEG CODEC. When all the compressed thumbnail image signals are produced, each of a compressed main image signal and compressed thumbnail image signal is recorded onto a memory card.

1. Field of the Invention
This invention relates generally to digital cameras and, more particularly, to a digital camera which records, to a recording medium, in a compressed state of main and size-reduced image signals corresponding to respective images of a subject taken successively.
2. Description of the Prior Art
According to DCF (Design rule for Camera File system), there is a need of producing thumbnail image signals in addition to main image signals so that both the image signals are recorded in a compressed state to a recording medium. Consequently, in the conventional digital camera, the main image signal is first compressed and then the thumbnail image signal produced from the main image signal is compressed so that both compressed signals are recorded to a recording medium. Meanwhile, during successive picture taking, totally-twice compression processes of main and thumbnail image signals must be waited for taking the next picture. After completing the last-time picture taking, all the compressed signals are recorded to the recording medium.
However, during successive picture taking, the picture-taking interval increases if the next picture taking is commenced after twice of compression processes have been done. It would be possible to shorten the picture-taking interval by compressing both the main and thumbnail image signals after completing successive picture taking. This however results in increase in the capacity of an internal memory.

Digital camera including the compression of size-reduced images after picture taking is completed


A multitrack recorder enables performance of easy identification as to whether a certain track is a monaural type or a stereo type, by means of level meters. The multitrack recorder can set tracks 3 and 4, among a plurality of tracks 1 through 4, to either a monaural type or a stereo type. When track types are stored in memory and when level meters are displayed in a display section, a width of each of track number displays and the number of level displays are changed between the monaural type and the stereo type.

A hitherto-known multitrack recorder records a sound signal into a plurality of tracks. A multitrack recorder makes it possible to record a rhythm guitar part in a track 1 and a lead guitar part in a track 2 by use of; for instance, an electric guitar and a vocal sound in a track 3 by use of a built-in microphone and mix down them to thereby generate and record a stereo signal.
It is desirable that the multitrack recorder be able to record a sound signal in as many tracks as possible. In the meantime, when an attempt is made to make the multitrack recorder compact in consideration of portability, limiting the number of tracks might be unavoidable. Measures that are conceivable in the circumstances are to limit the number of tracks to a certain number; for instance, four and make some of the tracks assignable to either a monaural type or a stereo type rather than fixing the tracks solely to monaural types to enhance user's convenience.
JP 2010-232950 A discloses an audio mixing device that displays signal levels of a plurality of channels as a level meter image and that also enables simultaneous observation of other pieces of information about the respective channels. When a signal type of an individual channel exhibits a correlation with a signal of an adjacent channel, the channel is displayed in a shape of a common link with the adjacent channel.
In a configuration where the number of tracks is limited to a constant number and where some of the tracks can be set to either a monaural type or a stereo type, it is necessary to accurately take hold of types of respective tracks during processing, such as a case where a sound signal recorded in a certain track is replicated (copied) to anther track. However, the configuration where the user memorizes which tracks are of a monaural type and which tracks are of a stereo type casts an additional burden on the user. In the meantime, it will also be troublesome for the user to check, each time, which tracks are of a monaural type and which tracks are of a stereo type on a dedicated screen, or the like. The user usually visually identifies a level meter in order to ascertain a level of a sound signal of each track. Hence, it is convenient for the user to be able to grasp a track type of each track at a glance on a display screen of the level meter.


Processing of mineral material containing precious metal with one or more sulfide minerals and non-sulfide gangue minerals including acid-consuming carbonate may include preparation of a sulfide concentrate by flotation with the flotation or conditioning prior to flotation using a gas comprising carbon dioxide. Flotation may be at an acidic pH without prior decomposition of the acid-consuming carbonate and may be without addition of acid for pH adjustment.

Significant amounts of precious metal, especially gold, are found dispersed in pyritic sulfide minerals, such as for example in pyrite, marcasite, pyrrhotite, arsenopyrite and/or arsenian pyrite. Often, very little of the gold contained in these sulfide minerals is recoverable by direct leaching with cyanide or other gold lixiviants. Rather, it is typically necessary to decompose the sulfide minerals to a significant extent to expose the gold and make the gold available to be leached. Sulfide mineral decomposition may involve an oxidative treatment, for example pressure oxidation or biooxidation. Processing may include preparing a sulfide concentrate by flotation prior to the oxidative treatment. Preparing a concentrate reduces the amount of material that must be processed in the oxidative treatment and provides higher sulfide sulfur concentrations that may be beneficial to drive desired reactions during some oxidative treatment techniques. For example, one oxidative treatment is acidic pressure oxidation in which a sulfide-containing mineral material, such as an ore, concentrate or ore/concentrate blend, is contacted with oxygen in an autoclave at elevated temperature and pressure in an acidic environment. In the autoclave, oxygen gas reacts with sulfide sulfur resulting in decomposition of sulfide minerals and generation of sulfuric acid. The sulfide sulfur oxidation is exothermic and the process may be thermally autogenous provided the feed contains a sufficiently high concentration of sulfide sulfur to generate adequate heat and sufficiently high acid concentrations.
Some ores contain significant quantities of acid-consuming carbonate that complicates processing. Many carbonate minerals, for example calcite, magnesite, siderite and dolomite, will react with sulfuric acid resulting in decomposition of the carbonate, generation of carbon dioxide and formation of sulfate salts. A small amount of acid-consuming carbonate in mineral material feed to acidic pressure oxidation feed may be acceptable, but as carbonate concentrations become larger consumption of sulfuric acid by the carbonate can be a significant detriment to the pressure oxidation operation. One way to address high concentrations of carbonate material in sulfide ores to be pressure oxidized is to pre-treat the ore with sulfuric acid to decompose the carbonates prior to being fed to the pressure oxidation autoclave, so that the carbonate will not be available to react in the autoclave and therefore will not interfere with desired reactions during pressure oxidation. However, the cost of sulfuric acid consumed in such a pre-treatment operation can be significant. For ores with high gold concentrations, the cost of pre-treatment may be justifiable, but for many carbonate-containing ores such pre-treatment may be cost prohibitive even with carbonate levels that are in the range of one weight percent, or even less in some cases.
Carbonate content in an ore can also be a significant problem for flotation processing to prepare a sulfide concentrate for oxidative treatment. For many sulfide gold ores, flotation to prepare a sulfide concentrate may be most effective if performed at an acidic pH, and feed slurries to flotation are adjusted to the desired acidic pH by addition of acid, commonly sulfuric acid. However, when the ore contains significant acid-consuming carbonate, significant acid is consumed to decompose the carbonate before the pH of the ore slurry can effectively be adjusted to the desired acidic pH for flotation. Additionally, as a result of the acidification precipitates may form that may have a very small size that can complicate flotation and post-flotation filtration of flotation concentrates, such as by causing filter plugging. Especially when mineral material contains significant acid-consuming carbonate in the form of calcite, very fine particles of calcium sulfate (gypsum) precipitate may form. The presence of such precipitates during flotation may interfere with flotation performance, which may lead to a need to perform flotation at a lower slurry solids density. Also, the presence of such precipitates in the flotation concentrate may interfere with effective dewatering of flotation concentrates, such as by filtration. Filtration plugging can become a significant problem as a result of such very fine precipitates.

Method for processing mineral material containing acid-consuming carbonate and precious metal in sulfide minerals


A four-phase (or multi-phase) generation circuit, related method of operation, and transceivers or other systems utilizing such a circuit, are disclosed herein. In one example embodiment, the circuit includes two input ports respectively configured to receive positive and negative differential input signals, and four output ports respectively configured to output first, second, third and fourth output signals, respectively, the second, third, and fourth output signals being respectively phase-shifted relative to the first output signal by or substantially by 90, 180, and 270 degrees. Also, the circuit includes four SR latches respectively including output terminals that are respectively coupled to the respective output ports. Further, the circuit includes two tunable delay circuits respectively coupled at least indirectly between the input ports and latches, and two comparison circuits configured to output respective feedback signals. The latches receive two delayed input signals provided by the delay circuits based upon the feedback signals.

Four-phase generators (e.g., quadrature generators) are employed in a variety of applications and circumstances, such as in the context of computer applications and communications applications involving radio frequency (RF) transmitters, receivers, or transceivers. Such four-phase generators are utilized to generate multiple output signals having different phases that are based upon one or more input signals that are lesser in number than the output signals, but that share the same frequency. The multiple output signals typically are identical or substantially similar to one another (e.g., in terms of magnitude, and/or amplitude, period, and/or waveform) except in terms of their phases.
Conventional four-phase generators can involve any of several concepts or techniques. For example, according to a first concept, frequency division is achieved by using an input clock signal that has a higher input clock frequency than the frequency of the output signals that are generated. Also for example, according to a second concept, a filter is employed to generate 90° phase shifts from an input signal to one or more output signals. Further for example, according to a third concept, a high-speed logic combination of already-existing differential quadrature signals can be employed to generate four-phase outputs from the already-existing differential quadrature signals.
Although such conventional concepts or techniques can be employed to generate four phases from one or more input or source signals (such as can be provided by a differential input clock), such conventional concepts or techniques each have one or more disadvantage(s). To begin, depending upon the implementation of these concepts, additional circuits may be needed to convert the 50% duty cycle outputs to 25%. Additionally, particularly with respect to the first concept involving the higher input clock frequency, this concept requires that a higher input frequency clock be generated or otherwise be available in the system, which in turn increases the system level complexity and power consumption.
Also, with respect to the second concept involving the use of a filter, this concept relies upon such a filter being tuned to the desired frequency in order to generate the desired 90° phase shifts. This narrow-band solution is sensitive to process variations and is not easily scalable to other frequencies. Further, with respect to the third concept involving high-speed logic, this concept can only be implemented in certain circumstances, insofar as the concept requires that existing differential signals be already available for use. Further, the high-speed logic employed by the third concept also can introduce additional phase error.
For at least one or more of these reasons, or one or more other reasons, it would be advantageous if new or improved systems, concepts, or circuits could be developed, and/or improved methods, processes, or techniques for operation or implementation could be developed, so as to address any one or more of the concerns discussed above or to address one or more other concerns or provide one or more benefits.

Negative-feedback four-phase generator with twenty-five percent duty cycle output


Systems and methods are described for maintaining a user's common data across multiple platforms. The common data is information about the user and graphical and design elements of publications that should be consistently presented across online, other electronic, and non-electronic platforms, such as websites, social networking profiles, electronic and printed business listings, email and print newsletters, business cards, letterhead, and the like. The common data may be stored and updated by a centralized or distributed system including one or more servers communicating with the platforms and with a content database that retains the common data in a stored data structure. The system may provide an interface to the user, receive common data elements input by the user, add the common data elements to the stored data structure, and distribute the common data elements to the platforms. The system may identify which platforms require which elements of the common data.

The Internet comprises a vast number of computers and computer networks that are interconnected through communication links. The interconnected computers exchange information using various services. In particular, a server computer system, referred to herein as a web server, may connect through the Internet to a remote client computer system and may send, to the remote client computer system upon request, one or more websites containing one or more graphical and textual web pages of information. A request is made to the web server by visiting the website's address, known as a Uniform Resource Locator ("URL"). Upon receipt, the requesting device can display the web pages. The request and display of the websites are typically conducted using a browser. A browser is a special-purpose application program that effects the requesting of web pages and the displaying of web pages.
Browsers are able to locate specific websites because each website, resource, and computer on the Internet has a unique Internet Protocol (IP) address. Presently, there are two standards for IP addresses. The older IP address standard, often called IP Version 4 (IPv4), is a 32-bit binary number, which is typically shown in dotted decimal notation, where four 8-bit bytes are separated by a dot from each other (e.g., 188.8.131.52). The notation is used to improve human readability. The newer IP address standard, often called IP Version 6 (IPv6) or Next Generation Internet Protocol (IPng), is a 128-bit binary number. The standard human readable notation for IPv6 addresses presents the address as eight 16-bit hexadecimal words, each separated by a colon (e.g., 2EDC:BA98:0332:0000:CF8A:000C:2154:7313).
IP addresses, however, even in human readable notation, are difficult for people to remember and use. A URL is much easier to remember and may be used to point to any computer, directory, or file on the Internet. A browser is able to access a website on the Internet through the use of a URL. The URL may include a Hypertext Transfer Protocol (HTTP) request combined with the website's Internet address, also known as the website's domain name. An example of a URL with a HTTP request and domain name is: http://www.companyname.com. In this example, the "http" identifies the URL as a HTTP request and the "companyname.com" is the domain name.
Domain names are much easier to remember and use than their corresponding IP addresses. The Internet Corporation for Assigned Names and Numbers (ICANN) approves some Generic Top-Level Domains (gTLD) and delegates the responsibility to a particular organization (a "registry") for maintaining an authoritative source for the registered domain names within a TLD and their corresponding IP addresses. For certain TLDs (e.g., .biz, .info, .name, and .org) the registry is also the authoritative source for contact information related to the domain name and is referred to as a "thick" registry. For other TLDs (e.g., .com and .net) only the domain name, registrar identification, and name server information is stored within the registry, and a registrar is the authoritative source for the contact information related to the domain name. Such registries are referred to as "thin" registries. Most gTLDs are organized through a central domain name Shared Registration System (SRS) based on their TLD.
The process for registering a domain name with .com, .net, .org, and some other TLDs allows an Internet user to use an ICANN-accredited registrar to register their domain name. For example, if an Internet user, John Doe, wishes to register the domain name "mycompany.com," John Doe may initially determine whether the desired domain name is available by contacting a domain name registrar. The Internet user may make this contact using the registrar's webpage and typing the desired domain name into a field on the registrar's webpage created for this purpose. Upon receiving the request from the Internet user, the registrar may ascertain whether "mycompany.com" has already been registered by checking the SRS database associated with the TLD of the domain name. The results of the search then may be displayed on the webpage to thereby notify the Internet user of the availability of the domain name. If the domain name is available, the Internet user may proceed with the registration process. Otherwise, the Internet user may keep selecting alternative domain names until an available domain name is found. Domain names are typically registered for a period of one to ten years with first rights to continually re-register the domain name.
The information on web pages is in the form of programmed source code that the browser interprets to determine what to display on the requesting device. The source code may include document formats, objects, parameters, positioning instructions, and other code that is defined in one or more web programming or markup languages. One web programming language is HyperText Markup Language ("HTML"), and all web pages use it to some extent. HTML uses text indicators called tags to provide interpretation instructions to the browser. The tags specify the composition of design elements such as text, images, shapes, hyperlinks to other web pages, programming objects such as JAVA applets, form fields, tables, and other elements. The web page can be formatted for proper display on computer systems with widely varying display parameters, due to differences in screen size, resolution, processing power, and maximum download speeds.
Websites can be generated from structured data stored in a database or other data store. In a basic implementation, the data can include multiple records having a data type and content, and a web programming interface can access the database, retrieve records having the desired data types, and add the content of those records to one or more web pages. Additionally, data formats and schema exist that optimize the structured data for inclusion on a website. For example, the Microdata format is a set of HTML tags used to delineate types of data on a web page. Microdata tags can be used in conjunction with a defined data type vocabulary, such as that provided by schema.org, to retain information relating to the data type of data extracted from the database and placed on the website. Retaining such information allows Internet search engines to better understand the content of a website.
The Internet continues to be increasingly valuable to individuals and businesses alike. More people use the Web for everyday tasks, from social networking, shopping, banking, and paying bills to consuming media and entertainment. E-commerce is growing, with businesses delivering more services and content across the Internet, communicating and collaborating online, and inventing new ways to connect with each other. It is advantageous for individuals and businesses to maintain an online presence, which may include presenting information about the individual or business on multiple online platforms. For example, a business might have its own website at www.thebusiness.com, business listings on GOOGLE Places for Business and BING Places for Business, a profile page on FACEBOOK, one or more blast email lists and a mobile application ("app") that customers download to their mobile device. These platforms can have different virtual locations (i.e. different domains) and partially or fully incompatible formats, despite sharing common information.
Information that is typically common across platforms normally includes the most important information. For individuals, this might be name, photo, phone number, TWITTER handle, blog or personal web page address, and the like. For businesses, this might be name, address, phone number, hours of operation, news feed, product information such as menus or inventory, and the like. Whether such information changes frequently or only on rare occasion, it is very important to the individual or business that the information is consistently presented across all of its online platforms. Unfortunately, the incompatibilities between platforms can require the individual or business to either manually update the information multiple times, or engage a web design firm to maintain the information at some expense and with some risk of errors or omissions as the information is repeatedly updated.
Relatedly, an individual or business may wish to maintain a consistent visual presentation, referred to herein as a theme, across its platforms. Platform incompatibility may prevent or limit the consistency of the theme. For example, color schemes, graphic elements, and layouts are all completely customizable for a standalone website, but FACEBOOK imposes a strict profile format where graphics and layout cannot be easily carried over. It would be advantageous to identify the elements of a theme that can be adapted for use on each platform, in order to best provide the desired consistent presentation. Further, changes to the theme could be more easily propagated across platforms.
Despite the increasing use of the Internet and other online or electronic platforms, individuals and businesses still have physical presences and use printed collateral to convey some of the information from their web presence. Again, the information conveyed on printed collateral, such as flyers, brochures, catalogs, business cards, newsletters, and the like, can include name, contact information, and other information that must be kept consistent. Additionally, printed collateral frequently determines or shares the theme or themes used online. Printed collateral can be designed electronically, using graphic design software such as ADOBE PHOTOSHOP, publishing software such as PAGEPLUS, and other software. These programs can store the information and graphics to be printed in design files that can be accessed by other programs or interfaces.

Method for maintaining common data across multiple platforms


Techniques for achieving tenant data confidentiality in a cloud environment are presented. A daemon process within a Tenant Storage Machine (TSM) manages a key store for a particular tenant of a cloud storage environment having multiple other tenants. Just TSM storage processes are given access to the key store. Data is decrypted for the particular tenant when access is needed and data is encrypted using encryption keys of the key store when written in the cloud storage environment.

Cloud computing is rapidly changing the Internet into a collection of clouds, which provide a variety of computing resources, storage resources, and, in the future, a variety of resources that are currently unimagined.
Specifically, cloud computing is a technology infrastructure that facilitates: supplementing, consuming, and delivering Information Technology (IT) services. The cloud environment provides elastic provisioning of dynamically scalable virtual services.
A tenant is considered as a subscriber of some amount of storage in the cloud or an application who owns part of the shared storage environment. Multi-tenancy is an architecture where a single instance of software runs on a server, which is serving multiple tenants. In a multi-tenant environment, all tenants and their users consume the service from a same technology platform, sharing all components in the technology stack including the data model, servers, and database layers. Further, in a multi-tenant architecture, the data and configuration is virtually partitioned and each tenant works with a customized virtual application instance.
In a Cloud Service Provider's environment, multiple customers, tenants, applications share a common storage infrastructure. The shared storage infrastructure includes storage controllers and raw storage disks. It is often a common scenario that some enterprise customers or users have a stringent requirement that their data is stored in an encrypted manner so that no one else can read their data.
Specifically today, whenever, data needs to be encrypted for confidentiality, several encryption algorithms are used with a key being stored at the tenant (or client) or at the server (storage controller).
So, tenant or client can manage the storage keys or the storage controller can manage the storage keys.
The problem with the key being stored at tenant (or client) is that in the case of key being lost by the tenant (or client), the encrypted data on the server becomes useless. This results in a complete loss of data.
The problem with the key being stored on the server (or the storage controller) is that, the administrator of the storage controller who knows the root password can use the key to decrypt the data. So, true confidentiality is never achieved this way.
Moreover in both the cases, there is a problem with the confidentiality of the data of the tenant.

Techniques for achieving tenant data confidentiality from cloud service provider administrators