Electric field coupling between floating gates of a high density flash EEPROM cell array has been found to produce errors in reading the states of the cells, particularly when being operated with more than two storage states per cell. The effect of this coupling is overcome by placing a conductive shield or insulating material with a low dielectric constant between adjacent floating gates, and/or by compensating for the coupling when reading the states of the cells.

This invention relates generally to flash electrically erasable and programmable read only memories (EEPROMS), and, more specifically, to such memories with a very high density of cells, particularly when operated with more than two threshold states (termed "multi-state" or "multi-level" operation) to store more than one bit of data in each cell.
Most existing commercial flash EEPROM products operate each memory cell with two ranges of threshold voltages, one above and the other below a breakpoint level, thereby defining two programmed states. One bit of data is thus stored in each cell, a 0 when programmed into one state and a 1 when programmed into its other state. A chunk of a given number of bits of data is programmed at one time into an equal number of cells. The state of each cell is monitored during programming so that application of programming voltages stops when the threshold level an individual cell is verified to have moved within the range that represents the value of the bit of data being stored in the cell.
In order to increase the amount of data stored in a flash EEPROM system having a certain number of storage cells, the individual cells are operated with more than two threshold level states. Preferably, two or more bits of data are stored in each cell by operating the individual cells with four or more programmable states. Three threshold breakpoint levels are necessary to define four different threshold states. Such a system is described in U.S. Pat. Nos. 5,043,940 and 5,172,338, which are being incorporated herein by this reference. In multi-state operation, an available operating voltage range of the individual cells is divided into an increased number of states. The use of eight or more states, resulting in storing three or more bits of data per cell, is contemplated. The voltage range of each state necessarily becomes smaller as the number of states is increased. This leaves less margin within each state to accommodate any error that might occur during operation of the memory system.
One type of error is termed a "disturb," wherein electrons are unintentionally added to or taken away from a floating gate during operation of the memory. One source of a disturb is the presence of a leaky oxide dielectric positioned between the floating gate and another conductive gate of a cell. The charge level programmed onto a floating gate of a cell changes when such a leaky oxide is present, thus leading to the possibility that the state of the cell will be incorrectly read if the change in charge has been large enough. Since few to no errors can be tolerated in a mass digital data storage system, a sufficient margin for this error is provided by making the voltage range allocated to each state sufficient to include an expanded range of voltages that can occur as the result of such disturbs. This necessarily limits the number of states that can be included in a multi-state flash EEPROM system since the total available voltage range is limited.
It is a general object of the present invention to provide flash EEPROM structures and operating techniques that improve the accuracy of data stored in and read from the memory, particularly when operating in a multi-state mode.
It is a more specific object of the present invention to shrink the size of a flash EEPROM array of cells on an integrated circuit chip without adversely affecting the ability to accurately program and read the memory, particularly when operating in a multi-state mode.

High density non-volatile flash memory without adverse effects of electric field coupling between adjacent floating gates


A semiconductor device package comprises a substrate (20) having a metallization pattern (22) on at least one surface, and a semiconductor device (10) having an active surface (12) and a grounded surface (14) on opposed sides. The semiconductor device is electrically attached to the substrate metallization pattern with the active surface (12) facing the substrate. A polymeric underfill material (30) substantially fills the space between the semiconductor device and the substrate. An electrically conductive material (35) covers the exposed grounded surface (14) of the semiconductor device and at least a portion of the metallization pattern (22), providing electrical connection between the grounded surface of the semiconductor and the metallization pattern (22) on the substrate.

Silicon integrated circuit chips are typically packaged in sealed enclosures, such as chip carriers or dual in-line packages (DIP), and interconnected with other components on printed circuit boards. The integrated circuit is typically connected to a carrier substrate with the active or upper surface of the integrated circuit facing away from the carrier substrate. Interconnections between the IC and the substrate is typically made by thin metal wires or wirebonds welded between the pads of the IC and the circuitry on the printed circuit board.
In an alternate packaging configuration known as flip chip, the integrated circuit is bonded directly to the substrate by means of solder bumps or other metal interconnects and is mounted with the active surface facing the printed circuit board. This type of interconnection eliminates the expense, unreliability, and low productivity of manual or automated wirebonding. It also allows the use of interior or array contacts as opposed to the limitation of using peripheral contacts with wirebonding methodology. The flip chip or control-collapse-chip-connection (C4) utilizes solder bumps deposited on wettable metal terminals of the chip and a matching footprint of solder wettable terminals on the substrate. The upside down flip chip is aligned to the substrate, and all interconnections are made simultaneously by reflowing the solder. This is opposite to the traditional method of bonding where the active side of the chip is facing up and is wirebonded to the substrate.
When chips are mounted in the conventional manner, that is, wirebonded, a ground connection to the backside ground plane of the chip can be made by forming a conductive connection between the backside ground plane of the chip and the ground of the printed circuit board. This is easily performed by means of conductive epoxy or solder, for example. In flip-chip devices the connection of the ground plane of the IC to the ground of the substrate is more difficult because now the ground plane is facing away from the substrate. Wirebonds may be formed between the ground of the IC and the ground of the substrate but this negates the advantages realized by the flip-chip mounting scheme.
A method of achieving a ground connection between the back side ground of the flip chip and the ground of the circuitry is needed that eliminates the cumbersome, costly and unreliable wirebonds.

Backplane grounding for flip-chip integrated circuit


Disclosed is a method for preparing a carbide-derived carbon-based anode active material. The method includes preparing carbide-derived carbon, and expanding pores of the carbide-derived carbon. Here, expanding of pores is performed as an activation process of heating the prepared carbide-derived carbon in the air. The pores formed inside the carbide-derived carbon can be expanded during the activation process in the preparation of the carbide-derived carbon-based anode active material. In addition, by applying the carbide-derived carbon to an anode active material, lithium secondary battery having improved charge-discharge efficiency can be prepared.

The present invention relates to a method for preparing an anode active material of a lithium secondary battery and an anode active material prepared by the same, and more particularly, to a method for preparing an anode active material based on carbide-derived carbon having pores therein and an anode active material prepared by the same.
Generally, carbon is classified into amorphous carbon, graphite, diamond, fullerene-like structures, nanotubes, and the like depending on properties thereof, and carbon having specific structures and properties can be created by varying reaction conditions. Graphite requires high temperature conditions and carbon atoms of graphite exhibit extremely low mobility. Diamond requires difficult reaction conditions based on high pressure or high-energy activation technology. Recently, with the development of nano-techniques, demand for techniques capable of controlling growth of atomic-level carbon materials has been increasing.
Carbon is mainly used as an anode material for secondary batteries, particularly, lithium secondary batteries. More particularly, hard carbon, which is non-graphite carbon, or graphitized soft carbon is mainly used as the anode material.
Graphite constituting a LiC6 structure has a theoretical capacity of 380 mAh/g based on a charge-discharge reaction mechanism of secondary batteries, and carbonized materials having a structure beyond such theoretical capacity based on the charge-discharge reaction mechanism have been developed in the art.
Carbide-derived carbon (CDC) is a carbon material prepared by selectively removing metal atoms from crystalline metal carbide, which is a compound of metal and carbon and has a highly crystalline structure, and nano-sized pores are formed at positions from which metal atoms are removed (Korean Patent Application Publication No. 10-2001-0013225 A).
The carbide-derived carbon allows efficient supply and discharge of reactants and by-products through the nano-sized pores, and has a large surface area. Therefore, efforts to use the carbide-derived carbon as an energy reservoir are ongoing, and although technology to apply the carbide-derived carbon to an anode material for secondary batteries has been developed (Korean Patent No. 10-0814817), the technology in the art has insufficient efficiency.
The present invention solves these problems, as well as others.

Method for preparing carbide-derived carbon-based anode active material and anode active material prepared by the same


A rotary printing machine with a sheet-surface treating device disposed between a last cyclically operating printing unit and a device for conveying sheets on a sheet pile, the sheet-surface treating device including at least one fixed drier past which the sheets are guidable, includes at least one module composed of two rotating conveying elements having a like circumferential speed for transporting the sheets along the sheet-surface treating device, the conveying elements carrying grippers for grasping a respective leading edge of one of the sheets, the sheets being supplied to the module and discharged from the module, respectively, during a rotation of the grippers in accordance with a printing cycle, a plurality of gripper arms, the grippers of a respective conveying element disposed first along a conveying path of the sheets being carried by at least one of the gripper arms, guiding elements for freely guiding the sheets otherwise, the grippers of the conveying element disposed second along the conveying path of the sheets being carried by at least one of the gripper arms, and rotating curved supporting elements arranged in cicumferential direction between the gripper arms so that the sheets are disposable thereon.

FIELD OF THE INVENTION
The invention relates to a rotary printing machine with a device for treating the surface of sheets and, more particularly, to a sheet-fed rotary printing machine having a delivery wherein at least one drier for varnish or printing ink is provided. In such rotary printing machines, conveying elements, such as chain conveyors or transfer drums, for example, which have grippers assembled thereon, are provided in the delivery, and have thermal drying devices, cooling devices, powdering devices or redampening devices assigned thereto for treating the surface of the sheets. The printed surface of the sheets are prevented thereby from smearing or smudging, and the sheets are prevented from sticking to one another.
At high machine speeds, in order to achieve the desired effect, it is necessary to employ a large amount of energy in the treatment of the surface and for the energy-active stage to have dimensions which are as large as possible. Heretofore known devices for treating the surface of the sheets have therefore require a great amount of space. For example, the construction shown in the published German Patent Document DE 66 03 661 U1 requires a relatively great erection height in order to accommodate vertically arranged chain conveyors. For a web-fed printing machine having a modular construction, the published European Patent Document WO 95/29813 A1 provides, for each module, a drier which is assigned to a web length running rectilinearly in a vertical direction.
In the construction shown in German Patent 688,935, a drying drum with a large circumference is used, the dry air serving for the drying being also effective during the rotation of the drum. The dwell time of the fresh printing ink in the drying air may be further lengthened if the diameter of the drying drum is increased in size. In addition to the large volume which has to be provided for the drying drum, a disadvantage arises in that the print on the surface of the sheets is damaged by resting on screen-like supporting elements. The supporting elements impair the effectiveness of the drying air supplied. Moreover, the provision of a co-rotating drier device is complicated from a construction standpoint.

Rotary printing machine with a device for treating the surface of sheets


An apparatus for manipulating a food item, the apparatus having a chassis, an actuator, a first jaw, and a second jaw. The actuator is connected to the chassis and rotatable about a pivot. The first jaw is connected to the chassis and mechanically linked to the actuator. The first jaw is further adapted to move along a first arc. The second jaw is also connected to the chassis and mechanically linked to the actuator. The second jaw is also further adapted to move along a second arc. Rotation of the actuator about the pivot in a first direction brings together the first jaw and the second jaw, the first and second jaws moving along the first and second arcs, respectively. Rotation of the actuator in a second direction opposite the first direction brings apart the first jaw and the second jaw, the first and second jaws moving along the first and second arcs, respectively.

The traditional preparation of food is oftentimes a labour intensive procedure that requires intricate manipulations and complex maneuvers. For example, preparing food can require, variously, bending, rolling, smoothing, pinching, lifting, stirring, and moving food items or aspects thereof.
Certain food preparation operations are particularly conducive to automation. For example, mechanical mixers and food processors can help reduce the manual effort required to mix and process ingredients. Conveyor belts may be employed, for example, to move items from one location to another.
Other food preparation operations are more complex, and accordingly, more complex machines may be required in order to perform such operations. The preparation of a croissant is one such example. While mixers and other standard machines may be used to prepare the dough and to shape the dough into a tubular shape, a croissant is typically crescent shaped, and in some circumstances, the tips of the croissant are made to overlap or be connected.
There are existing methods of shaping a croissant. For example, one method involves carrying tubular croissants on a conveyor, having such tubular croissants engage with a vertical piston to stop its forward motion, and using specially positioned rollers to bend the tips of the croissant together. This method is, however, very dependent upon the accuracy of the initial placement of the individual piece. If the initial placement of the croissant is incorrect or unexpected, the resulting shape of the croissant is non-optimal. More generally, the motion of bringing together the tips of a croissant, and potentially overlapping such tips, is a complex maneuver not readily possible to effect using simple machines and operations.
Accordingly, there is a need for an apparatus for shaping a croissant which is intended to assist with eliminating or alleviating some of all of the aforementioned problems associated with the prior art approaches.


A process for fabricating an integrated circuit package includes: selectively etching a leadframe strip to define a die attach pad and at least one row of contact pads; mounting a semiconductor die to one side of the leadframe strip, on the die attach pad; wire bonding the semiconductor die to ones of the contact pads; releasably clamping the leadframe strip in a mold by releasably clamping the contact pads; molding in a molding compound to cover the semiconductor die, the wire bonds and a portion of the contact pads not covered by the clamping; releasing the leadframe strip from the mold; depositing a plurality of external contacts on the one side of the leadframe strip, on the contact pads, such that the external contacts protrude from the molding compound; and singulating to provide the integrated circuit package.

According to well known prior art IC (integrated circuit) packaging methodologies, semiconductor dice are singulated and mounted using epoxy or other conventional means onto respective die attach pads (attach paddles) of a leadframe strip. Traditional QFP (Quad Flat Pack) packages incorporate inner leads which function as lands for wire bonding the semiconductor die bond pads. These inner leads typically require mold locking features to ensure proper positioning of the leadframe strip during subsequent molding to encapsulate the package. The inner leads terminate in outer leads that are bent down to contact a mother board, thereby limiting the packaging density of such prior art devices.
In order to overcome these and other disadvantages of the prior art, the Applicants previously developed a Leadless Plastic Chip Carrier (LPCC). According to Applicants' LPCC methodology, a leadframe strip is provided for supporting several hundred devices. Singulated IC dice are placed on the strip die attach pads using conventional die mount and epoxy techniques. After curing of the epoxy, the dice are wire bonded to the peripheral internal leads by gold (Au), copper (Cu), aluminum (Al) or doped aluminum wire bonding. The leadframe strip is then molded in plastic or resin using a modified mold wherein the bottom cavity is a flat plate. In the resulting molded package, the die pad and leadframe inner leads are exposed. By exposing the bottom of the die attach pad, mold delamination at the bottom of the die pad is eliminated, thereby increasing the moisture sensitivity performance. Also, thermal performance of the IC package is improved by providing a direct thermal path from the exposed die attach pad to the motherboard. By exposing the leadframe inner leads, the requirement for mold locking features is eliminated and no external lead standoff is necessary, thereby increasing device density and reducing package thickness over prior art methodologies. The exposed inner leadframe leads function as solder pads for motherboard assembly such that less gold wire bonding is required as compared to prior art methodologies, thereby improving electrical performance in terms of board level parasitics and enhancing package design flexibility over prior art packages (i.e. custom trim tools and form tools are not required). These and several other advantages of Applicants' own prior art LPCC process are discussed in Applicants' U.S. Pat. No. 6,229,200, the contents of which are incorporated herein by reference.
In applicant's own U.S. Pat. No. 6,585,905, issued Jul. 1, 2003 and incorporated herein by reference, a process is provided for fabricating a leadless plastic chip carrier in which the semiconductor die sits in a portion of the die attach pad that is reduced in thickness. The leadframe strip is selectively etched to define a pattern for the die attach pad and the contact pads such that a portion of the die attach pad has reduced thickness compared to the thickness of the contact pads. The semiconductor die is mounted in the portion of the die attach pad with reduced thickness, followed by wire bonding and overmolding. This structure provides for several advantages. For example, the package profile can be reduced and the length of the wire bonds from the semiconductor die to the die attach pad and to the contact pads is reduced, thereby reducing electrical impedance in the package. Also, the three-dimensional nature of the die attach pad provides additional exposed metal for adhering to the molding compound, thereby providing a more robust package.
Still further improvements in high performance integrated circuit (IC) packages are driven by industry demands for increased thermal and electrical performance, decreased size and cost of manufacture.

Integrated circuit package and process for fabricating the same


An improved magnet assembly apparatus is provided for a filter cartridge magnetic attachment such as disclosed in U.S. Pat. No. 5,510,024. With the present invention, the improvement is comprised of a first shunt element attached to a first end of the first particle-attracting magnet. A second shunt element is attached to a first end of the second particle-attracting magnet, and a first or more shunt magnets are connected between the first shunt element and the second shunt element. The first shunt element and the second shunt element are made from iron-containing material. The first particle-attracting magnet has a first longitudinal axis, the second particle-attracting magnet has a second longitudinal. The first longitudinal axis and the second longitudinal axis are parallel, and the first shunt magnet has a first longitudinal shunt axis which is perpendicular to the first longitudinal axis and the second longitudinal axis. With one embodiment of the invention, the first longitudinal axis the second longitudinal axis and the first longitudinal shunt axis lie in a common plane. With another embodiment of the invention, a second shunt magnet is connected between the first shunt element and the second shunt element. With another embodiment of the invention, a third shunt magnet is connected between the first shunt element and the second shunt element. The first particle-attracting magnet, the second particle-attracting magnet, the first shunt magnet, the second shunt magnet, and the third shunt magnet are cylindrical magnets.

1. Field of the Invention
The present invention relates generally to an improved magnet assembly, and more particularly, to a magnet assembly especially useful as a filtering device or as a filter cartridge magnetic attachment for magnetically collecting metallic particles within a filter.
2. Description of the Prior Art
This patent is an improvement of the filter cartridge magnetic attachment set forth in U.S. Pat. No. 5,510,024 by the same inventor herein. In this respect, U.S. Pat. No. 5,510,024 is incorporated herein by reference.
In U.S. Pat. No. 5,510,024, a first magnet 18 and a second magnet 20 are employed along with either a single shunt 34 or a pair of shunts comprised of a first shunt member 50 and a second shunt member 52. The use of only two magnets and up to two shunts, such as described in U.S. Pat. No. 5,510,024, provides a somewhat limited magnetic configuration that influences the metal particles inside the filter cartridge 14. In this respect, it would be desirable if a filter cartridge magnetic attachment can provide a wide variety of magnetic configurations with a wide variety of magnetic strengths.
In U.S. Pat. No. 5,510,024, the first magnet 18 and the second magnet 20 are spaced apart from one another by a predetermined distance and fit into complementary reception channels in the heat sink 22. To provide additional magnetic configurations, it would be desirable if additional magnets could be configured so that two of the magnets fit into the complementary reception channels in the heat sink 22 as described in U.S. Pat. No. 5,510,024.
In other contexts, throughout the years, a number of innovations have been developed relating to configurations of magnets and shunts, and the following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 2,613,246, 2,936,408, 3,067,366, 3,168,686, 4,578,663, and 4,816,796. It is noted, however, that none of the configurations of magnets and shunts disclosed in U.S. Pat. Nos. 2,613,246, 2,936,408, 3,067,366, 3,168,686, 4,578,663, and 4,816,796 are suitable for use with the reception channels in the heat sink 22 disclosed in U.S. Pat. No. 5,510,024.
Thus, while the foregoing body of prior art indicates it to be well known to use magnets and shunts in a variety of configurations, the prior art described above does not teach or suggest an improved filter cartridge magnetic attachment which has the following combination of desirable features: (1) provides a wide variety of magnetic configurations with a wide variety of magnetic strengths; and (2) permits additional magnets to be configured so that two of the magnets fit into the complementary reception channels in the heat sink as described in U.S. Pat. No. 5,510,024. The foregoing desired characteristics are provided by the unique improved filter cartridge magnetic attachment of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.


Provided is a pedal system that can adjust control pedals on the basis of driver's physical conditions. The adjustable pedal system includes a support bracket that includes a guide groove formed in a substantially vertical direction and a predetermined hole, and is connected to a vehicle; a linear actuator that includes a drive arm linearly movable in a substantially vertical direction and applies a driving force to the drive arm; and a pedal arm. The pedal arm has a hinge hole that is connected to the drive arm by a first pin, a sliding slot that is connected to the predetermined hole by a second pin and is formed to be inclined with respect to the guide groove, and a pedal. The hinge hole is connected to the drive arm by a first pin, and the sliding slot is connected to the predetermined hole by a second pin and is formed to be inclined with respect to the guide groove. In this case, the portion of the pedal arm near the sliding slot slides with respect to the second pin, so that the position of the pedal arm can change.

1. Field of the Invention
The present invention relates to control pedals of an automobile, and more particularly, to control pedals that can be adjusted on the basis of driver's physique.
2. Description of the Related Art
For several years, makers or designers of automobiles have had an interest in ergonomic aspects for drivers with different physiques. An automotive control unit such as a steering wheel of an automobile is designed to be adjustable for the drivers with different physiques, so that the drivers with different physiques can drive the automobile. Since the driving comfort of the driver is an important factor, in respect to safety and ergonomics, the automotive control unit becomes very important.
Control pedals are commonly provided to a vehicle, and are stepped on by a driver's foot. The control pedals for a brake and an accelerator, which are separated from each other, are provided in the vehicle. If a vehicle is provided with a manual transmission, another control pedal used to drive a transmission clutch is provided in the vehicle. Front seats of the vehicle are configured to be movable along tracks to front and/or rear directions. However, by moving only the seat, it still does not sufficiently provide proper adjustment for a driver. Accordingly, there is a demand for a system that is used to adjust the positions of the control pedals so as to correspond to drivers with different physiques. This system is called an APS (Adjustable Pedal System).
An example of a system in the related art relating to the adjustable pedal system is disclosed in U.S. Pat. No. 6,571,660. The adjustable pedal system disclosed in U.S. Pat. No. 6,571,660 includes a support bracket, a pedal assembly, first and second pins, and a linear actuator. The support bracket is connected to a vehicle, and includes first and second slots that are spaced apart from each other and are not parallel to each other. The pedal assembly is disposed adjacent to the support bracket, and includes a pedal. The first and second pins are provided to the pedal assembly, and are inserted through the first and second slots, respectively. The linear actuator is connected to the pedal assembly so that the pedal assembly slides along the support bracket. The adjustable pedal system having the above-mentioned structure allows a driver to easily adjust the position of the pedal.
However, according to the slots and the pins, which cause the pedal assembly to slide along the support bracket, in the adjustable pedal system disclosed in U.S. Pat. No. 6,571,660, the slots are formed in the support bracket. Accordingly, the pedal assembly in the support bracket is exposed due to the slot formed in the support bracket. For this reason, there is a possibility that particles, fluid, and impurities enter the connection part between the pedal assembly and the pins coupled to the pedal assembly. This causes problems in the adjustable pedal system in that it is difficult to accurately control the adjustable pedal system.
In addition, the adjustable pedal system disclosed in U.S. Pat. No. 6,571,660 has been applied to one control pedal. However, since a common vehicle includes at least two pedals (for example, an accelerator pedal and a brake pedal), to adjust each of the positions of the control pedals becomes complicated and there is a problem in that an actuator should be provided for each of the control pedals. Further, it is necessary for the accelerator pedal and the brake pedal to be interlocked with each other to be adjusted


A method and apparatus for encoding and decoding data using an overall code comprising an outer parity-check and an inner parallel concatenated convolutional, or turbo code. The overall code provides error probabilities that are significantly lower than can be achieved by using turbo codes alone. The output of the inner code can be punctured to maintain the same turbo code rate as the turbo code encoding without the outer code. Multiple parity-check codes can be concatanated either serially or in parallel as outer codes. Decoding can be performed with iterative a posteriori probability (APP) decoders or with other decoders, depending on the requirements of the system. The parity-check code can be applied to a subset of the bits to achieve unequal error protection. Moreover, the techniques presented can be mapped to higher order modulation schemes to achieve improved power and bandwidth efficiency.

Advances in error-correcting codes, such as convolution codes and trellis codes, have enabled designers of digital communications systems to achieve increased bit rates for a given level of error rate performance. One of the most significant developments in the area of digital error correcting codes are the recursive convolution codes collectively known as "turbo codes." Turbo codes operate by combining a plurality of encoders with permuters to iteratively encode data to improve performance using a corresponding number of soft input/soft output decoders which operate iteratively.
An early description of turbo codes appears in C. Berrou, et. al, "Near Shannon limit error-correcting coding and decoding: Turbo codes," Proc. 1993 Int. Conf. Communication (Geneva, Switzerland, May 1993), pp. 1064–1070. Berrou, et. al discloses a parallel-concatenated turbo code. The input data is applied to a first convolutional encoder and an interleaved version of the input data is applied to a second convolutional encoder. Some of the redundant bits generated by the encoders may be subjected to a puncturing prior to the mapping step in order to improve bandwidth efficiency.
While turbo codes can reduce the level of received signal-to-noise ratio to achieve a desired level of error rate performance, the complexity of turbo codes can create significant end-to-end delay, or latency, which is undesirable in many applications. In addition, parallel concatenated turbo codes, like the one described in Berrou, exhibit an error floor phenomenon wherein the improvement in coding gain is far less dramatic at lower error rates and may be comparable to, or even worse than, the lower error rates achieved using more conventional encoding and decoding.
Serial concatenated turbo codes have also been suggested as disclosed by S. Benedetto, et al, in "Serial concatenation of interleaved codes: Performance analysis, design, and iterative decoding," IEEE Trans. Inform. Theory, vol. 44, pp. 909–926, May 1998. In a serially concatenated turbo code, the input data is applied to a first convolutional encoder and the output bits of the first encoder, after interleaving, are used as the input bits for a second convolutional encoder. The error floor phenomenon associated with parallel-concatenated turbo codes is less pronounced for serial-concatenated turbo codes, thereby providing better coding gain at lower error rates. However, the performance of these codes in the low signal-to-noise regions is generally not as good as turbo codes. Furthermore, these serial-concatenated turbo codes generally generate more redundant bits than in the parallel case, so that they are less bandwidth-efficient. Moreover, they too require prohibitive complexity with associated delays.
Neither the parallel-concatenated nor the serial-concatenated turbo codes described above are bandwidth efficient; each of the designs has a bandwidth efficiency of less than two bits per two-dimensional signal point when used with quadrature phase-shift-key (QPSK) modulation. More bandwidth-efficient parallel concatenated turbo codes have been designed, including, for example, "Bandwidth efficient parallel concatenated coding schemes," by S. Benedetto, et al, Electron. Lett., vol. 31, pp. 2067–2069, 1995, and P. Robertson, et al, and "Coded modulation scheme employing turbo codes," Electron. Lett., vol. 31, pp. 1546–1547, 1995. The arrangements described in these references achieve high coding gains at high error rate while featuring an improved bandwidth efficiency of a full 2 bits per 2D signal point by using rate-2/3 trellis codes designed jointly with a 2D 8-PSK signaling constellation in contrast to the convolutional codes with the 2D 4-PSK constellation used in the Berrou design. However, the Benedetto codes still exhibit the undesirable error floor phenomenon and associated long delays.
Moreover, the error floor tends to occur at high error probabilities when the turbo code is based on very simple constituent codes and when the block length is short (generally from several hundred to several thousand bits). For wireless communication systems, short block lengths and simple constituent codes are usually required. One motivation for these requirements is to keep the decoder simple enough to implement the decoding in a cost-effective manner. The complexity of the decoder has currently limited the application of turbo codes to the reverse link, so that the turbo decoder is implemented in hardware at the base station. In addition, turbo codes can be used in hybrid automatic repeat request (ARQ) schemes that use code combining, but these methods have not been implemented in any of the current telecommunication standards. One probable reason for this is that previously proposed code-combining ARQ techniques all require additional iterative maximum a posteriori (MAP) decoding of the entire packet when additional code symbols are received. This additional iterative decoding results in significantly higher processing requirements and longer delays. Thus, it desirable to consider other code structures that can provide similar or better performance than turbo codes while also reducing the complexity.
To overcome the inherent limitations of turbo codes, several authors have suggested the use of an outer code error correction code with a turbo inner code. J. D. Andersen suggested the use of an outer Bose-Chaudhuri-Hochquenghem (BCH) cyclic, error-correcting, code in the Proceedings of the 1995 IEEE International Symposium on Information Theory and the October Issue ofIEE Electronics Letters. Narayanan and Stuber suggested a variation on this scheme in the September 1997 issue of IEEE Communications Letters. Kim and Lee considered a variation of the BCH outer code in the Proceedings of the 2000 IEEE International Symposium on Information Theory, as did Takeshita et al in the April 2001 IEEE Transactions on Communications. A Reed-Solomon (a type of non-binary BCH) code was used an outer code with a turbo inner code by Costello et al in the Proceedings of the 1996 IEEE International Symposium on Information Theory and Its Applications and by Valenti in the Proceedings of the 2000 IEEE Military Communications Conference.
In addition, single parity-check codes and concatenations of single parity-check codes have been investigated by many authors, including Caire et al in the Proceedings of the 1994 Global Telecommunications Conference, Hagenauer et al in the March 1996 IEEE Transactions on Communications, Ping et al in the September 1997 IEE Electronics Letter and the Proceedings of the 1998 IEEE International Conference on Communications, and Rankin and Gulliver in the August 2001 IEEE Transactions on Communications.
However, while mitigating the inherent problems of using a turbo code alone, the above proposed paired inner and outer error correcting codes suffer from a significant reduction in code rates and fail to utilize the soft-outputs of the turbo decoder. Therefore, there is a need in the art to provide a new error-correcting code comprising an outer code error correction code with a turbo inner code that can significantly outperform existing coding schemes without requiring a significant reduction in code rate.
The following patents, describing various error coding schemes, are incorporated herein by reference to the extent they are not inconsistent with the disclosure, teachings, and principles of the subject invention: U.S. Pat. Nos. 4,785,451; 5,406,570; 5,446,747; 5,563,897; 5,729,560; 5,920,578; 5,996,104; 6,023,783; 6,028,897; 6,122,763; and 6,351,832.
All patents, patent applications, provisional applications, and publications referred to or cited herein, or from which a claim for benefit of priority has been made, are incorporated herein by reference in their entirety to the extent they are not inconsistent with the explicit teachings of this specification.

Method and coding means for error-correction utilizing concatenated parity and turbo codes


A varistor comprises a varistor portion, a metal portion, and buffer portion. The varistor portion has a varistor element body exhibiting a nonlinear current-voltage characteristic and two electrode portions. The metal portion has a thermal conductivity higher than that of the varistor element body. The buffer portion is disposed between the varistor portion and metal portion so as to be bonded to each of the varistor portion and metal portion and mainly composed of glass. The two electrode portions are arranged in the varistor element body so as to be electrically insulated from each other while exposing at least a portion of each thereof from an outer surface of the varistor element body. The metal portion and varistor portion are joined firmly to each other. The heat transmitted to the varistor can efficiently be diffused from the metal portion.

1. Field of the Invention
The present invention relates to a varistor and a light-emitting apparatus comprising the varistor.
2. Related Background Art
Known as a varistor is one comprising a element body having a varistor element body exhibiting a nonlinear current-voltage characteristic and a pair of internal electrodes disposed so as to interpose a portion of the varistor element body between them, and a pair of terminal electrodes formed on an outer surface of the element body and respectively connected to their corresponding internal electrodes (see, for example, Japanese Patent Application Laid-Open No. 2002-246207).


In a trigger mechanism for firearms, in particular of the adjustable type for target-shooting pistols, the actuator of the mechanism is constituted by an elastic element (29) which is pivoted to the hammer (23) in an upward position and is pivoted, in a downward position, to an element (39) which can slide on the body (5) of the firearm; by acting on the sliding element, the elastic element is inclined so as to vary the direction of the actuation force with respect to the lever arm formed by the fulcrum (25) of the hammer with the upper pivot (27) of the elastic element. The safety device disengages the trigger from the operation of the firing mechanism.

Several types of safety mechanisms are known: some safely devices are adapted to lock the trigger actuation lever assembly; other devices are adapted to place a rigid member in front of the striking mass; still others are adapted to extend the actuation spring.
A common type of safety mechanism, for example, is simply constituted by a safety pin which, in safety position, makes contact with a portion of the trigger in order to prevent any movement thereof, whereas in normal firing position it leaves the trigger free to perform its movements.
This type of safety device has the advantage of being extremely simple from the constructive point of view and of being adaptable to numerous and various firing mechanisms; however, in practice it cannot be used for example in firing mechanisms which provide an adjustment of the trigger, as occurs in target-shooting pistols.
UK Patent No. 213,805 discloses a self-loading pistol having a toggle link interposed between the hammer and the percussion spring. Depressible means operable by the act of gripping the pistol handle are provided to impart an initial movement of the toggle link from a safety position into a ready position. In one embodiment, the percussion spring is oscillable, being accomodated in a casing which is oscillably mounted in the handle.
Due to the complicated firing mechanisms and to the particular operating conditions, target-shooting pistols are normally not provided with a safety mechanism. Safety mechanisms, such as the one described above, would in fact interfere with the extremely sensitive operation of the trigger mechanism.
It is nonetheless advisable to provide a safety mechanism for this type of firearms as well, and this need is now even more strongly felt because of new regulations enforced by some countries.

Safety device for trigger mechanisms, in particlar for firearms


A thin film transistor has a gate electrode; a gate insulating layer provided so as to cover the gate electrode layer; a pair of impurity semiconductor layers forming source and drain regions which is provided so that at least part of each of them overlaps the gate electrode layer and which are provided with a space therebetween; a microcrystalline semiconductor layer provided over the gate insulating layer in part of a channel length; a semiconductor layer provided over the gate insulating layer so as to cover at least the microcrystalline semiconductor layer; and an amorphous semiconductor layer provided between the semiconductor layer and the pair of impurity semiconductor layers. An impurity element which reduces the coordination number of silicon and generates dangling bonds is made to exist in the semiconductor layer.

1. Field of the Invention
The present invention relates to thin film transistors.
2. Description of the Related Art
As one type of field effect transistor, a thin film transistor in which a semiconductor layer which is provided over a substrate having an insulating surface is used for a channel formation region is known. For the semiconductor layer used in the thin film transistor, techniques using amorphous silicon, microcrystalline silicon, and polycrystalline silicon are disclosed (see Patent Documents 1 to 5). Thin film transistors have been used for, for example, liquid crystal television devices and have been put to practical use as switching transistors of pixels which form a display screen.    [Patent Document 1] Japanese Published Patent Application No. 2001-053283    [Patent Document 2] Japanese Published Patent Application No. 05-129608    [Patent Document 3] Japanese Published Patent Application No. 2005-049832    [Patent Document 4] Japanese Published Patent Application No. 07-131030    [Patent Document 5] Japanese Published Patent Application No. 2005-191546

Semiconductor Energy Laboratory Co., Ltd.


A wire lead-in device for leading wires into a building from the upper side of a roofing material laid on a roof structural member includes a main body having a transversely long plate-like base part that is mounted on the roofing material, an insertion hole that penetrates through the base part and through which the wires are capable of being inserted, a peripheral wall that surrounds the wires passing through the insertion hole and extending to an eaves side from right, left, and ridge sides, and extends upward from the base part, and of which lower ends are inclined upward toward the eaves side, and an inclined bottom wall that couples the inclined lower ends of the peripheral wall, and a lid member that is detachably mounted on the main body and is capable of closing an upper opening of the peripheral wall.

1. Field of the Invention
The present invention relates to a wire lead-in device for leading wires such as distributing cables of solar cell modules into a building from the upper side of a roofing material laid on a roof structural member.
2. Description of the Related Art
The present applicant has proposed a wire lead-in device (wire lead-in tool) for leading wires such as distributing cables from solar cell modules and an antenna cable from a television antenna into a building from the upper side of a roofing material laid on a roof structural member such as rafter and a roofboard configuring a roof of the building (See, Japanese Patent Application Laid-open No. 2008-266977). The wire lead-in device includes a main body and a cover. The main body has a box shape extending in the roof flow direction (inclined direction) and is opened upward and toward the eaves. The cover covers the upper opening of the main body. An insertion hole through which the wires can be inserted is formed in the main body of the wire lead-in device in the vicinity of an end portion at the ridge side. Further, the box-shaped main body of the wire lead-in device includes a flange-form mounting part extending from the longer side of the bottom portion in the direction orthogonal to the roof flow direction. The mounting part is mounted on the roofing material, so that the main body is mounted on the roofing material.
The above-mentioned wire lead-in device can lead the wires into the building from the upper side of the roof in the following manner. That is, the main body of the wire lead-in device is mounted on the roofing material such that the insertion hole is matched with a through-hole formed on the roofing material and the wires are extended into the building through the insertion hole in the main body and the through-hole from the opened eaves-side end portion of the main body. The wire lead-in device can prevent rainwater from entering the building through the insertion hole with the box-shaped main body extending in the roof flow direction.
The conventional wire lead-in device has the bottom surface of the main body, which is a flat surface extending in the roof flow direction. This arises a problem that the main body cannot be mounted on the roofing material when the roofing material formed by a metal plate (metal roof) or the roofing material having a bent part or a step with respect to the roof flow direction is used. To be specific, for example, when the metal roof is laid on the roof structural member such as the roofboard in a horizontal roofing manner, the metal roof is inclined such that a space between the metal roof and the roofboard becomes larger toward the eaves side from the ridge side when focusing one metal roof. When the wire lead-in device is mounted on the metal roof in this state, the inclined thin metal roof is pressed by the bottom surface of the wire lead-in device so as to be in parallel with the roofboard and the metal roof is largely bent by the eaves-side end portion of the wire lead-in device. If the metal roof is bent, there arises a problem that the strength of the metal roof is lowered. Further, in this case, there is a risk that a ridge-side portion (coupling part coupling the metal roofs) of the metal roof located at the eaves side is crushed by the bottom surface of the wire lead-in device. If the place is crushed, there arises a problem that waterproof performance of the metal roof is lowered significantly. For this reason, the wire lead-in device cannot be mounted, resulting in a problem.
Therefore, for example, there is a problem that even if a user desires to install the solar cell module on roof, the user gives up installing the solar cell module because the wire lead-in device cannot be mounted. Alternatively, there is the following problem. That is, the cost for installation of the solar cell module is largely increased if the roofing material is replaced such that the wire lead-in device can be mounted for installing the solar cell module. In addition, in the conventional wire lead-in device, the opening on the eaves-side end portion through which the wire is led out is formed over the substantially entire height of the main body. This arises a risk that rainwater enters from the eaves-side end portion.


A method for producing a metal mask for screen printing is provided, in which dross that is deposited at the time a boring operation is conducted via a laser beam is removed, without causing warpage or bending. The method for producing a metal mask for screen printing includes steps of: forming openings in the metal plate by melting the metal plate at positions irradiated by the laser beam; and ejecting an abrasive onto the other surface of the metal plate after the openings are formed. The abrasive ejected in the abrasive ejection step is one having a predetermined flat shape (plate-shaped abrasive), so as to form a plate shape having a flat surface, or an elastically deformable abrasive, with an average grain diameter of a dispersed or carried abrasive grain being 1 mm to 0.1 μm, and which is ejected at an incident angle of equal to or less than 80 degrees with respect to the other surface of the metal plate, and at an ejection pressure of 0.01 MPa to 0.7 MPa or at an ejection speed of 5 m/sec to 150 m/sec, so as to slide along the other surface of the metal plate.

1. Field of the Invention
The present invention relates to a method for producing a metal mask for screen printing. More specifically, the present invention relates to a method for producing a metal mask for screen printing that includes steps of: forming opening portions for printing (hereinafter referred to as "opening") via laser irradiation, and removing dross (burrs) deposited by the opening forming process.
2. Description of the Related Art
A "metal mask" formed with a pattern of openings that corresponds to the printing pattern on a metal plate such as stainless steel is employed in fields that require relatively detailed printing, such as solder paste printing or photoresist layering during a method for producing printed circuits, IC substrates, etc. Accordingly, when such a metal mask abuts the surface of the product to be treated, and a solder paste or ink paste is applied from the opposing surface with a squeegee, etc., printing is performed on the surface of the product to be printed with the paste, corresponding to the pattern of openings.
A metal mask employed in this type of screen printing is formed with openings that correspond to the printing pattern of the abovementioned metal plate. Accordingly, various conventional etching technologies may be employed as the method for forming this type of pattern of openings, such as melting by laser irradiation, electrolytic polishing, etching by chemicals, etc. However, with the current popularization of CAD and CAM, by controlling the trajectory of laser irradiation in accordance with a predesigned predetermined print pattern, via computer numerical control (CNC) that employs CAD data, etc., even complicated patterns of openings can be processed relatively easily. Accordingly, operations for forming the above-described openings via laser irradiation have been frequently employed in recent years.
However, in this type of opening formation via laser irradiation, the openings are formed by melting the metal plate at the positions of laser irradiation. Accordingly, a portion of the metal melted by laser irradiation is attached and hardened at an edge of an opening on the surface of the metal plate on the opposite side from the side that was irradiated, and the raised edge portions of the openings where burrs arise are referred to as the portions where "dross" is deposited (refer to FIG. 2).
Therefore, when a metal mask with dross deposits like this is employed in screen printing and the dross deposited surface thereof is employed as the surface to be in close contact with the product to be printed, the metal mask cannot be brought into close contact with the surface of the product to be printed. As a result, because of the space arising between the metal mask and the surface of the product to be printed, detailed printing cannot be conducted. Conversely, when the dross deposited surface is positioned on a side opposite to that of the surface to be printed, the inflow of the paste into the inside of the openings is inhibited by the dross, so that an accurate amount of solder paste or ink paste cannot be supplied.
Accordingly, when boring a metal mask via this type of laser irradiation, an operation for removing this dross is conducted after the openings are formed by laser irradiation.
However, one method for removing these dross deposits involves, for example, etching the surface of a metal mask by being immersed in a chemical such as ferric chloride, etc., or electro-polishing the surface, with a metal mask placed in an electro-polishing solution.
However, when the abovementioned method is employed, not only are the dross deposits removed, but the edge portions surrounding the openings formed in the metal mask are also etched and polished. Accordingly, because the post-processed openings become larger at the front and rear surfaces, and the hole diameter in the center portion is formed into a narrowed drum shape (bilaterally symmetrical conical notch), the narrowed central portion presents resistance against the passage of solder paste or ink paste through the openings, which impedes the supply of solder paste or ink paste.
Moreover, because the diameters are enlarged by etching the edges of the openings, the actual printed shape becomes larges than the intended printing shape. As a result, even if the openings are formed into a shape with corners, for example, a planar rectangular shape, etc., because these corners are removed by etching, etc., and formed into a rounded shape, the printing of an extremely detailed shape cannot be performed, so that the quality of the printing is decreased.
In addition, when performing the elimination of dross deposited by electro-polishing or chemical etching, a chemical such as an electro-polishing solution or an etching solution is employed. Accordingly, when these chemicals are directly disposed of, etc., they cause considerable stress on the environment.
In such cases, a treatment is required to detoxify these chemicals before disposal, with the expenses required for this treatment being passed on to the cost of the metal mask itself, which in turn increases the production cost.
Thus, in recent years, conversion from a chemical treatment that employs chemicals, etc., to a dry-type treatment that does not employ chemicals, etc., has been sought.
As a method for performing dross removal via such a dry-type treatment, a method for producing a metal mask is provided whereby the surface of the metal plate is ground by sandblasting after a predetermined pattern of openings is formed by laser irradiation (refer to Japanese Patent No. 3160084).
Moreover, in the metal mask production method described in the abovementioned Japanese Patent No. 3160084, the sandblasting is intended not only to remove the deposited dross, but also to provide a satin-like finish to the surface of the metal mask (refer to paragraph [0014] of the abovementioned Japanese Patent No. 3160084). Unlike this method, however, a method has also been proposed whereby, rather than forming a satin-like finish, a glossy or mirror-like finish is provided on the surface of the product to be treated via the ejection of an abrasive. As the abrasive for providing this glossy or mirror-like finish to the product to be treated, an elastic abrasive is provided in which abrasive grains are supported on the surface of a core consisting of an elastic body, or the abrasive grains are dispersed by being kneaded into the core consisting of the elastic body, etc. (Japanese Unexamined Patent Application Publication No. 2006-159402; Japanese Unexamined Patent Application Publication No. 2001-207160; and Japanese Patent No. 2957492).

Method for producing metal mask for screen printing


A bushing allows for adjustability of a position of a headrest. The bushing includes a head portion having an opening and a passageway opening. The bushing also includes a body portion defining an internal passageway. The passageway opening of the head portion is aligned with the internal passageway of the body portion. The body portion includes a wall surrounding an area of reduced thickness, and a protrusion is located on an internal surface of the area of reduced thickness. The bushing also includes a moveable portion received in the opening of the head portion. The moveable portion is moveable between a first position where a feature engages a notch of a post receivable in the internal passageway of the body portion and the passageway opening of the head portion to retain the headrest in a position and a second position where the feature is disengaged from the notch of the post, allowing the post and the headrest to move relative to the bushing.

A vehicle seat can include an adjustable headrest mounted to a backrest of the vehicle seat. The headrest can be moved in a generally vertical direction relative to the seat. Two posts are mounted to the headrest. Two guide sleeves are located within the backrest of the vehicle seat, and a bushing is received in each of the two guide sleeves. Each post is receivable in one of the two guide sleeves.
Each post includes a plurality of notches. One bushing includes a mechanism that is received in one of the notches, securing the post and the attached headrest in a position. When the headrest is to be moved to another position relative to the backrest of the vehicle seat, the mechanism of the bushing is removed from the notch of the post, allowing the post, and therefore the attached headrest, to slide in the generally vertical direction relative to the backrest of the vehicle seat to a desired position. Once the headrest is in the desired position, the mechanism is released to allow the mechanism to engage another notch of the post, securing the headrest in the desired position.

Headrest adjustment mechanism for vehicle seats


A transdermal system in the form of a patch that comprises a tamoxifen derivative and an absorption-promoting additive for systemic administration.

1. Field of the Invention
The most important medicament for the treatment of specific tumour forms, especially hormone-dependent breast tumours, is the antioestrogen tamoxifen (1-(p-3-dimethylaminoethoxyphenyl)-trans-1,2-diphenylbut-1-ene).
2. Background Art
Tamoxifen is available commercially in various oral formulations under various Trade Marks, in particular Novaldex.RTM.. Tamoxifen is administered perorally in the long-term treatment of tumours at from 10 to 40 mg per single dose. The daily dose is from 20 to 40 mg. In the case of long-term therapy, however, tamoxifen exhibits serious undesired side-effects, for example, the paradoxical stimulation of the ovaries, which presents a limiting factor in its long-term use. During passage through the liver after absorption from the gastrointestinal tract, the active metabolite 4-hydroxytamoxifen is produced from the tamoxifen and, on a molecular basis, is more active than tamoxifen by a factor of approximately 100. That value is based on the publication by Katzenellenbogen et al. (Bioactivities, oestrogen receptor interactions, and plasminogen activator-inducing activities of Tamoxifen and Hydroxytamoxifen Isomers in MCF-7 Human Breast Cancer Assays) in Cancer Research, 44 (1984) 112-119, on MCF-7 cell lines. The substance isomeric to 4-hydroxytamoxifen, 3-hydroxytamoxifen (Droloxifen), likewise binds very much more strongly to oestrogen receptors in vitro, that is by a factor of from 20 to 60, than tamoxifen itself. As in the case of 4-hydroxytamoxifen, the oestrogenically active component is less than in tamoxifen, whereas the antioestrogenic activity is in each case higher. The oestrogenic component of both tamoxifen and its hydroxy derivatives is associated with the stereoisomeric E-form, whilst the antioestrogenic component results from the Z-form. The hydroxy derivatives of tamoxifen undergo extensive metabolisation in the liver, at any rate after oral administration, as described, for example, by DE-C-2 807 599. The substances are very rapidly conjugated and thereby inactivated (Rochefort et al, (Cellular and molecular mechanism of action of antioestrogens) in J. Steroid Biochem., 19 (1983) 69-74).
On account of the high receptor affinity of hydroxytamoxifen derivatives, their therapeutic use would be desirable but, using the peroral route, it is very severely restricted because of their rapid inactivation in the liver. For that reason EP-B-0 169 214 and EP-B-0 151 326 describe the topical administration of 4-hydroxytamoxifen in an aqueous/alcoholic gel. The gel is provided for the topical application of 4-hydroxytamoxifen. In Cancer Research, 46 (1986) 1521-1525, Mauvais-Jarvis et al describe the topical administration of an alcoholic solution to 12 female patients. In that study, the distribution of radioactive 4-hydroxytamoxifen in breast tissue was examined. The authors discovered that the percutaneous topical application of 4-hydroxytamoxifen resulted first of all in a high retention of the active ingredient in the oestrogen receptor-containing breast tissue and transition to the plasma compartment was delayed for a very prolonged period. Only approximately 0.5% of the dose applied was found unchanged in the plasma.
The provision of a systemic method of administration is desirable, however, in the case of, for example, metastasising tumours, where 4-hydroxytamoxifen cannot be administered topically in every case. The percutaneous form of medicament described in the above-mentioned EP-B publications, that is the aqueous/alcoholic gel, is disadvantageous. Such gels cannot be applied per se to defined cutaneous areas, and cannot be protected from external influences, such as being washed off, or rubbed off by clothing, during the period of action. The delivery of active ingredient from such gels is accordingly very variable and unreliable.
The problem underlying the invention is to make available a systemic method of administration for tamoxifen derivatives.

Transdermal system in the form of a patch comprising a tamoxifen derivative


Antisense compounds, compositions and methods are provided for modulating the expression of Phospholipase A2 Group IV. The compositions comprise antisense compounds, particularly antisense oligonucleotides, targeted to nucleic acids encoding Phospholipase A2 Group IV. Methods of using these compounds for modulation of Phospholipase A2 Group IV expression and for treatment of diseases associated with expression of Phospholipase A2 Group IV are provided.

Phospholipase A2s (PLA2s) are a ubiquitous family of enzymes which have been shown to mediate several cellular responses including metabolism, phospholipid digestion, host defense, apoptosis and signal transduction. The PLA2 enzymes are abundant in nature with a strong presence in snake and insect venoms and the pancreatic fluids of mammals (Kramer and Sharp, FEBS Lett., 1997, 410, 49-53).
Although there are several forms of PLA2 enzymes in mammalian tissues, each with a distinct localization, structure, regulation and function, the common role of PLA2 enzymes is to maintain the integrity of the cell membrane. Following activation, PLA2 enzymes hydrolyze phospholipids, producing free fatty acids and lysophospholipids. These lipid hydrolysis products have been shown to act as second messengers and metabolic precursors for molecules having major implications in inflammation and degenerative disorders such as Alzheimer's disease (Murakami et al., Crit. Rev. Immunol., 1997, 17, 225-283). Consequently, these enzymes have been the topic of intense study in an effort to develop novel therapeutic agents against inflammatory and degenerative diseases.
Phospholipase A2 Group IV (also known as cytosolic Phospholipase A2), a member of the PLA2 family of enzymes, is found in most mammalian tissues and preferentially cleaves arachidonate-containing phospholipids. In mammalian cells, the predominant fatty acid component of phospholipids is arachidonic acid. This fatty acid once liberated from the phospholipid is the precursor to a group of pro-inflammatory molecules known as eicosanoids which include prostaglandins, leukotrienes, and thromboxanes (Kramer and Sharp, FEBS Lett., 1997, 410, 49-53).
Phospholipase A2 Group IV is unique in that it is the only member of the PLA2 family that exhibits properties of a receptor-regulated protein. This means that the activation of Phospholipase A2 Group IV is triggered in response to extracellular stimuli including ligand binding. A variety of stimuli have been shown to activate Phospholipase A2 Group IV including growth factors, cytokines, mitogens, vasoactive peptides, integrin engagement, and interferons (Kramer and Sharp, FEBS Lett., 1997, 410, 49-53). In addition, stress stimuli such as oxidation, hyperglycemia and UV light have also been shown to activate Phospholipase A2 Group IV (Murakami et al., Crit. Rev. Immunol., 1997, 17, 225-283).
Manifestations of altered Phospholipase A2 Group IV regulation appear in both cell and tissue injury as well as disease states and the products of Phospholipase A2 Group IV hydrolysis have been shown to contribute to inflammatory and degenerative diseases. It is known that during ischemia, the concentration of free fatty acids in the brain increases, the most predominant being arachidonic acid presumably liberated by the action of Phospholipase A2 Group IV (Kramer et al., J. Lipid Mediat. Cell Signal., 1996, 14, 3-7). Using antibodies to Phospholipase A2 Group IV, other studies have shown that there is an elevated level of the Phospholipase A2 Group IV protein in the brains of Alzheimer's disease patients suggesting that an active inflammatory process occurs in the disorder (Stephenson et al., Neurobiol. Dis., 1996, 3, 51-63).
Furthermore, the phosphorylation state of Phospholipase 10 A2 Group IV has been implicated in the process of apoptosis. It is currently believed that sustained phosphorylation is necessary for the activation of Phospholipase A2 Group IV in apoptotic cells (OBrien et al., J. Immunol., 1998, 161, 1525-1532).
Inhibitors of Phospholipase A2 Group IV have been used to elucidate the role of Phospholipase A2 Group IV in hypotonic cell swelling in human neuroblastoma cell lines. These studies showed that AACOCF3 (arachidonyl trifluoromethylketone) reduced the release of arachidonic acid from the cells by inhibiting Phospholipase A2 Group IV thereby reducing cellular swelling (Basavappa et al., J. Neurophysiol., 1998, 79, 1441-1449). Another inhibitor, 3,3-Dimethyl-6-(3-lauroylureido)-7-oxo-4-thia-1-azabicyclo[3,2,0] heptane-2-carboxylic acid, a beta lactam, was shown to partition into the phospholipid bilayer and compete with the phospholipid substrate for the active site of Phospholipase A2 Group IV (Burke et al., J. Enzyme Inhib., 1998, 13, 195-206).
Wu et al. demonstrated that an antisense oligonucleotide targeted to the initiation site of human Phospholipase A2 Group IV and the Phospholipase A2 Group IV inhibitor, 4-bromophenacyl bromide significantly inhibited TNF-induced cytotoxicity in U937 human leukemic cells and concluded that disruption of Phospholipase A2 Group IV activation may represent a possible mechanism by which leukemia cells may become resistent to TNF-mediated apoptosis (Wu et al., Cancer Res., 1998, 58, 633-640). Other studies using an antisense targeted to the first 21 bases in the coding sequence of the high molecular weight Phospholipase A2 Group IV showed that increased Phospholipase A2 Group IV synthesis occurs when skin is exposed to UV doses sufficient to cause erythema and that an S-oligonucleotide antisense to Phospholipase A2 Group IV and methyl arachidonate fluorophosphate, a Phospholipase A2 Group IV specific inhibitor, blocked this effect (Gresham et al., Am. J. Physiol., 1996, 270, C1037-1050). In addition, monocytes cultured in the presence of an antisense oligonucleotide targeted to 16 bases just downstream from the initiation site of Phospholipase A2 Group IV showed reduced chemokine-induced chemotaxis (Locati et al., J. Biol. Chem., 1996, 271, 6010-6016).
These strategies, however, have not been expanded to the therapeutic level of treatment and consequently there remains a long felt need for additional agents capable of effectively inhibiting Phospholipase A2 Group IV function.

Antisense modulation of phospholipase A2 group IV expression


Configuration of a hinge for avoiding likely collection of water provides a connector to prevent difficulty of opening or closing a cover by freezing of the hinge. A connector mounted in an electric vehicle and connected with a connector of a charging cable is provided with a housing, a cover rotatively pivoted about the housing so as to open or close the cover, and a shaft. The cover is provided with a pair of cover side mounting plates including a shaft hole passing the shaft therethrough, and the housing is provided with a pair of housing side mounting plates including a shaft hole passing a shaft therethrough, and positioning the pair of cover side mounting plates therebetween. The pair of cover side mounting plates is provided with a boss cylindrically upstanding from each of faces opposite to the pair of housing side mounting plates, and passing the shaft therethrough.

A connector 201 shown in FIGS. 7 to 11 is a conventional one that has been employed for an electric vehicle, and that is connected with a connector 9 of a charging cable for charging a battery of the electric vehicle (see PTL 1).
The connector 201 is provided with a housing 202, a cover 203 rotatively pivoted about the housing 202 so as to open or close openings 221a and 222a of the housing 202, a lock 204 rotatively pivoted about the housing 202 so as to keep a state by engaging with an edge 233 of the cover 203 in which the cover 203 covers the openings 221a and 222a, with the openings 221a and 222a covered, and shafts 207 and 208.
The aforementioned housing 202 is formed of synthetic resin, which is provided with a housing main body 220, a flange 223 annularly disposed on outer surface of the housing 220, a pair of housing side mounting plates 224 disposed away from each other on the outer surface of the housing 220 for attaching the cover 203, and a pair of lock mounting plates 225 disposed away from each other on the outer surface of the housing 220 for attaching the cover 204. In the pair of housing side mounting plates 224 is disposed a shaft hole 224a passing a shaft 207 therethrough. Also, in the pair of lock mounting plates is disposed a shaft hole passing a shaft 208 therethrough.
The aforementioned housing 220 is provided with a plurality of terminal cavities 222, and a housing cavity 221 receiving a hood of the connector 9 of the charging cable. The terminal cavity 222 extends in a direction of engaging with the connector 9 of the charging cable, at an upper end and a lower end of which openings 222a and 222b are formed, respectively. From the lower end opening 222b is inserted a terminal having electric wire (not shown), from the upper end opening 222a is inserted a terminal of the connector 9 of the charging cable (not shown). These terminal having electric wire and the connector 9 of the charging cable 9 are engaged with each other within the terminal cavity 222.
The aforementioned cover 203 is formed of synthetic resin, which is provided with a plate 232 stacked on the upper end of the housing 220, an edge 233 disposed on an outer edge of the plate 232, and a base 230 disposed on an outer edge of the plate 232 and an opposite side of the edge 233. The base 230, as shown in FIG. 8, is provided with a extension 236 extending from an outer edge of the plate 232, a pair of cover side mounting plates 237 and 238 upstanding from the extension 236 and opposing each other. The pair of cover side mounting plates 237 and 238 is provided with shaft holes 237a and 238a passing the shaft 207 therethrough.
Also, the pair of cover side mounting plates 237, 238 is positioned between the pair of housing side mounting plates 224, and the shaft 207 is passed through the shaft holes 237a, 238a of the pair of cover side mounting plates 237, 238 and the shaft hole 224a of the pair of housing side mounting plates 224, resulting in the cover 203 being rotatively pivoted about the housing 202. The cover 203, when the connector 9 of the charging cable is inserted into the housing 202, also opens the openings 221a, 222a, and closes the openings 221a, 222a except in the case of charging to prevent water or dust from entering therein.
The aforementioned lock 204 is formed of synthetic resin, and provided with a shaft hole 241 passing the shaft 208 therein. The lock 204 is positioned between the pair of lock mounting plates 225 of the housing 202, and the shaft 208 is passed through the shaft hole 241 and a shaft hole of the pair of lock mounting plates 225, so as to be rotatively pivoted about the housing 202.


Methods, systems and network elements are described to improve the speed of handover in a mobile radio telecommunications system. In one embodiment a mobile terminal (114) transmits a list of addresses of network nodes (102, 103, 105, 122, 125) to a target base station (106) in preparation for setting up a new radio link to the target base station (106). The list of addresses can be used by the target base station (106) to select a node (122, 125) which is common to both the old and the new communication path and to address this node directly without requiring a cross-over switch network query. The new path (122, 110, 106) can then be set up quickly ready for the handover to target base station (106). In a further embodiment the network distributes pre-authenticated signatures for a mobile terminal (114) to the nodes (102, 103, 105, 122, 125) of the network currently supporting a communication. This allows local verification of a mobile terminal (114) when it attempts to set up a new radio link with a target base station (106). In yet a further embodiment the target base station (106) starts fast power control with the mobile terminal (114) before the new communications path (125, 110, 106) has been set up through the network.

Cellular mobile telephone systems rely on the reuse of radio frequencies in different cells or radio coverage areas. When a mobile terminal moves from communication with a base station in one cell (original base station) to another it is necessary to "handover" the mobile terminal to the base station (target base station) of the new cell. Handovers may be passive or active, i.e. a handover may be necessary when there is no active communication and the mobile terminal is "camped" on the current cell and must be transferred to the new cell (passive handover) or when there is an active communication which must be transferred from the current to the target base station (active handover). In order to avoid loss of data during an active handover it is preferred if the handover is quick. In order to improve the speed of handovers both "seamless" and "soft" handovers have been proposed. A seamless handover is a "hard" handover (new connection to the target base station is made at the time of loss of the old connection) in which the network connections up to the target base station are reserved and synchronised so that when the actual handover takes place there is the minimum of interruption between breaking the communication with the old base station and connecting through to the new base station. In a soft handover the mobile terminal communicates with both the old base station and the target base station at the same time and the network may decide, based on certain communication qualities or other criteria, when the signals arriving via the target base station are acceptable and the link to the original base station may be broken.
Hard handover methods may suffer from suddenly varying signal strength. The deterioration of the signal quality of communications with the original base station may be masked by shadowing and widely varying fading on the current communication channel so that the reduction in signal quality which triggers the handover may occur suddenly and catastrophically (for example, the "corner effect"). In this situation communication with the original base station is lost suddenly and a handover procedure which relies on a handover request being sent to the original base station may fail. Schemes have been proposed to deal with this situation, e.g. on loss of communication with the original base station the mobile terminal attempts a forward handover, i.e. it tries to make contact with a target base station and the network attempts to set up the new route through the network from the target base station. Setting up the new network path takes some time, particularly as the network has not been prepared in any way for this emergency operation, so that it is almost impossible with this method not to loose some data. Very often the complete communication is lost.
An alternative is to allow communication with more than one base station at the same time so that sudden loss of communication with one base station has no affect on the current communication. A method and a system for providing a communication with the mobile terminal through more than one base station during the handover process are disclosed in U.S. Pat. No. 5,625,876. Using this system, a communication between the mobile terminal and the end user is not interrupted by a handoff from the original base station to a target base station. This type of handover may be considered as a "soft" handover in that communication with the target base station is established before communication with the original base station is terminated. When the mobile terminal is in communication with two base stations, a single signal for the end user may be created from the signals from each base station by a cellular or personal communication system controller.
In systems in which a mobile terminal may communicate with several base stations at the same time, e.g. CDMA systems, mobile terminal assisted handoff may operate based on the signal strength of beacon or pilot signals from several sets of base stations as measured by the mobile terminal. An Active Set is the set of base stations through which active communication is established. The Neighbour Set is a set of base stations surrounding an active base station comprising base stations that have a high probability of having a pilot or beacon signal strength of sufficient level to support communication of adequate quality. The Candidate Set is a set of base stations having a pilot or beacon signal strength of sufficient level to establish communication.
When communications are initially established, a mobile terminal communicates through a first base station and the Active Set contains only the first base station. The mobile terminal monitors the pilot or beacon signal strength of the base stations surrounding at and each of these is allocated to the Active Set, the Candidate Set, or the Neighbour Set. When a pilot or beacon signal of a base station in the Neighbour Set exceeds a predetermined threshold level, the base station is added to the Candidate Set and removed from the Neighbour Set of the mobile terminal. The mobile terminal communicates a message to the original base station identifying the new base station. A cellular or personal communication system controller decides whether to establish communication between the new base station and the mobile terminal. Should the cellular or personal communication system controller decide to do so, the cellular or personal communication system controller sends a message to the new base station with identifying information about the mobile terminal and a command to establish communications therewith. A message is also transmitted to the mobile terminal through the original base station. The message identifies a new Active Set that includes the original and the new base stations. The mobile terminal searches for the new base station transmitted information signal and communication is established with the new base station without termination of communication through the original base station. This process can continue with additional base stations.
When the mobile terminal is communicating through multiple base stations, it continues to monitor the signal strength of the base stations of the Active Set, the Candidate Set, and the Neighbour Set. Should the signal strength corresponding to a base station of the Active Set drop below a predetermined period of time, the mobile terminal generates and transmits a message to report the event. The cellular or personal communication system controller receives this message through at least one of the base stations with which the mobile terminal is communicating. The cellular or personal communication system controller may decide to terminate communications through the base station having a weak pilot or beacon signal strength.
The cellular or personal communication system controller upon deciding to terminate communications through a base station generates a message identifying a new Active Set of base stations. The base station through which communication is established sends a message to the mobile terminal. The cellular or personal communication system controller also communicates information to the relevant base station to terminate communications with the mobile terminal. The mobile terminal communications are thus routed only through base stations identified in the new Active Set. In a cellular or personal communication telephone system, maximising the capacity of the system in terms of the number of simultaneous telephone calls that can be handled is also extremely important. If the mobile terminal is communicating simultaneously with several base stations, for example, when the mobile terminal is close to the boundaries of several different cells, additional radio and network resources are occupied which reduces the total capacity of the system. Hence, it is advantageous to limit the number of simultaneous communications of the same data using up radio capacity. Further, a high bit-rate, high priority mobile terminal which approaches a cell boundary may be operating at high power due to poor communication channels. This high power signal may seriously increase the noise level in the target cell. Generally, fast power control of the mobile terminal from the target base station will only be effective after the soft handover is complete. During this delay the users in the target cell may receive poor communication quality and/or loss of their calls.
As mobile cellular telephone systems have become more sophisticated, the handover requirements have also become more complex. In particular, there is an increase in the types of communications supported by mobile telecommunication systems and the requirements of these communications may be widely different. Important parameters of any communication may be its urgency, i.e. how quickly must the handover take place and how much delay or interruption is acceptable, its bandwidth, its minimum or preferred signal quality, its data rate, its priority, i.e. is the communication a premium service which may take priority over less important messages. Conventionally, certain types of data are considered to require a very quick handover with little loss or delay of the communication, e.g. telephone conversations. The increasing use of Internet telephones indicates, however, that delays in voice communications may be acceptable provided there is a significant cost saving. In addition, there is an increasing use of voicemail. Some telephone users only use their fixed telephones for outgoing calls and switch all ingoing calls to voicemail leaving them undisturbed until they wish to create a communication. With voicemail it is only necessary that the voice information is recorded accurately, exactly when it arrives is not of such a great importance. These changes in voice communications mean that different levels of service may be provided by the mobile communication network operator, e.g. a high price voice communication with high urgency and priority and a low price voice communication in which delays in duplex communications are possible and have to be accepted. On the other hand, certain types of data transmissions suffer greatly if there is an interruption during handover. Also, the bandwidth for different types of voice or data transmissions may vary widely, e.g. video, computer file downloads, voice or fax. Thus, there are several different qualities of service (QoS) which may be required for any particular transmission. During a handover the required QoS of the current transmission may be one of the parameters which influences the handover decision, i.e. can the new path support the required QoS. Checking the QoS for the new path requires knowledge about the properties of the new route from the target base station through the network to the end user to decide whether or not it meets the minimum QoS or the present QoS of the current transmission. This increase in sophistication of the handover decision increases its complexity and the time taken for its successful completion. For example, if one of the QoS requirements of an existing transmission is its priority i.e. it has a higher priority than other transmissions in the old cell or new cell it may be necessary to terminate lower priority communications in the target cell or to arrange for them to be handed over to another cell before the high priority communication can itself be handed over.
Summarising the above, there is a need for a very fast handover which can accommodate QoS requirements such as priority, urgency, bandwidth or cell or packet delay and which is easy to implement.

Method and apparatus for setting up a communication with a target base station in a cellular or cordless mobile telecommunications system


Concerning an all-optical switch which makes use of a nonlinear change of a refractive index of a nonlinear waveguide caused by absorption of a control light, a method that an electrostatic field is applied to the nonlinear waveguide is known as an effective one for shortening a lifetime of the carrier which obstructs an improvement of a repetition frequency of a switching operation. The semiconductor nonlinear waveguide is constituted of a pin-structure which comprises a nondoped InGaAsP optical waveguide, an under cladding layer formed of a N-type InP substrate and an upper cladding layer formed of a p-type InP layer and etc. Moreover, the under and upper cladding layers are electrically shortcircuited via upper and lower electrodes. Since a builtin voltage caused by a difference in Fermi level between n and p-type cladding layers is applied to a InGaAsP optical waveguide, and electrostatic field can be applied to the optical waveguide of the pin structure to some extent without using a constant-voltage power supply. By application of the aforementioned electrostatic field, the effective lifetime of the carrier is shortened, and a repetition frequency of an switching operation of the all-optical switch can be improved.

The invention relates to a semiconductor nonlinear waveguide and an optical switch comprising a semiconductor nonlinear waveguide, and especially to a semiconductor nonlinear waveguide and an optical switch used in a field of an optical fiber communication and an optical information process.
In an all-optical switch comprising a semiconductor nonlinear waveguide, if a period of repetition of the control light pulses is shorter than the lifetime of the carriers generated in a core of the semiconductor nonlinear waveguide, the all-optical switch operates in a condition that the carriers accumulate in the core of the semiconductor nonlinear waveguide. The accumulation of the carriers degrades the nonlinear property of the semiconductor nonlinear waveguide, and obstructs the realization of the all-optical switch with excellent performances. Accordingly, it can be admitted that a method proposed in Japanese Patent Kokai 4-3125, in which an electrostatic field is applied to the semiconductor nonlinear waveguide to shorten the lifetime of the carrier, is an effective one for deducing the accumulation of the carriers, but the structure of the all-optical switch becomes complicated.
Accordingly, it is an object of the invention to provide a semiconductor nonlinear waveguide, in which an electrostatic field can be applied to a core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
It is a further object of the invention to provide a semiconductor nonlinear waveguide, in which an electrostatic field can be applied to an InGaAsP core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
It is a still further object of the invention to provide an optical switch according to a Mach-Zehnder interferometer having a pair of semiconductor nonlinear waveguides, in each of which an electrostatic field can be applied to a core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
It is a yet further object of the invention to provide an optical switch according to a Mach-Zehnder interferometer having a pair of semiconductor nonlinear waveguides, in each of which an electrostatic field can be applied to an InGaAsP core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
It is a yet still further object of the invention to provide an optical switch having a single semiconductor nonlinear waveguide, in which an electrostatic field can be applied to a core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
It is an additional object of the invention to provide an optical switch having a signal semiconductor nonlinear waveguide, in which an electrostatic field can be applied to an InGaAsP core layer of the semiconductor nonlinear waveguide without using an external constant-voltage power supply.
According to the first feature of the invention, a semiconductor nonlinear waveguide comprises:
a nondoped core layer formed of a medium showing a nonlinear refractive index caused by absorption of a control light,
an under cladding layer of a first conductivity type formed under the nondoped core layer,
an upper cladding layer of a second conductivity type formed on the nondoped core layer, and
means for electrically shortcircuiting the under and upper cladding layers.
According to the second feature of the invention, a semiconductor nonlinear waveguide comprises:
a n-type InP substrate,
a nondoped InGaAsP optical waveguide of a strip structure formed on the n-type InP substrate,
nondoped InP layers formed on both sides of the nondoped InGaAsP optical waveguide,
a p-type InP layer formed on the nondoped InGaAsP optical waveguide and the nondoped InP layers,
a p-type InGaAs cap layer formed on the p-type InP layer,
electrodes respectively formed on an obverse surface of the InGaAs cap layer and a reverse surface of the n-type InP substrate, and
means for electrically shortcircuiting the electrodes formed on the obverse and reverse surfaces.
According to the third feature of the invention, an optical switch comprises:
a Mach-Zehnder interferometer provided with a pair of semiconductor nonlinear waveguides on both arms thereof,
wherein a refractive index of each of the semiconductor nonlinear waveguides changes by absorption of a control light, and
means for supplying the semiconductor nonlinear waveguides with the control light pulses in turn at a predetermined difference in time, which is shorter than a relaxation time of the change of the refractive index of each of the semiconductor nonlinear waveguides,
wherein each of the semiconductor nonlinear waveguides comprises:
a nondoped core layer formed of a medium showing a nonlinear refractive index,
an under cladding layer of a first conductivity type formed under the nondoped core layer,
an upper cladding layer of a second conductivity type formed on the nondoped core layer, and
means for electrically shortcircuiting the under and upper cladding layers.
According to the fourth feature of the invention, an optical switch comprises:
a Mach-Zehnder interferometer provided with a pair of semiconductor nonlinear waveguides on both arms thereof,
wherein a refractive index of each of the semiconductor nonlinear waveguides changes by absorption of a control light, and
means for supplying the semiconductor nonlinear waveguides with the control light pulses in turn at a predetermined difference in time, which is shorter than a relaxation time of the change of the refractive index of each of the semiconductor nonlinear waveguides,
wherein each of the semiconductor nonlinear waveguides comprises:
a n-type InP substrate,
a nondoped InGaAsP optical waveguide of a strip structure formed on the n-type InP substrate,
nondoped InP layers formed on both sides of the nondoped InGaAsP optical waveguide,
a p-type InP layer formed on the nondoped InGaAsP optical waveguide and the nondoped InP layers,
a p-type InGaAs cap layer formed on the p-type InP layer,
electrodes respectively formed on an obverse surface of the InGaAs cap layer and a reverse surface of the n-type InP substrate, and
means for electrically shortcircuiting the electrodes formed on the obverse and reverse surfaces.
According to the fifth feature of the invention, an optical switch comprises:
a semiconductor nonlinear waveguide, which shows a change in a refractive index by absorption of a control light,
means for separating a signal light into two linearly polarized signal lights perpendicular to each other,
means for generating a difference in a propagation time between the two linearly polarized signal lights perpendicular to each other,
means for propagating the two linearly polarized signal lights perpendicular to each other through the semiconductor nonlinear waveguide,
means for supplying a control light to the semiconductor nonlinear waveguide at a predetermined time, and
means for canceling the difference in the propagation time between the two linearly polarized signal lights perpendicular to each other,
wherein the nonlinear waveguide comprises:
a nondoped core layer formed of a medium showing a nonlinear refractive index,
an under cladding layer of a first conductivity type formed under the nondoped core layer,
an upper cladding layer of a second conductivity type formed on the nondoped core layer, and
means for electrically short circuiting the under and upper cladding layers.
According to the sixth feature of the invention, an optical switch comprises:
a semiconductor nonlinear waveguide, which shows a change in a refractive index by absorption of a control light,
means for separating a signal light into two linearly polarized signal lights perpendicular to each other,
means for generating a difference in a propagation time between the two linearly polarized signal lights perpendicular to each other,
means for propagating the two linearly polarized signal lights perpendicular to each other through the semiconductor nonlinear waveguide,
means for supplying a control light to the semiconductor nonlinear waveguide at a predetermined time, and
means for canceling the difference in the propagation time between the two linearly polarized signal lights perpendicular to each other,
wherein the nonlinear waveguide comprises:
a n-type InP substrate,
a nondoped InGaAsP optical waveguide of a strip structure formed on the n-type InP substrate,
nondoped InP layers formed on both sides of the nondoped InGaAsP optical waveguide,
a p-type InP layer formed on the nondoped InGaAsP optical waveguide and the nondoped InP layers,
a p-type InGaAs cap layer formed on the p-type InP layer,
electrodes respectively formed on an obverse surface of the InGaAs cap layer and a reverse surface of the n-type InP substrate, and
means for electrically shortcircuiting the electrodes formed on the obverse and reverse surfaces.

Semiconductor nonlinear waveguide and optical switch