The present invention is notably directed to a resistive memory element comprising a resistively switchable material coupled to two conductive electrodes, wherein the resistively switchable material is an amorphous compound comprising carbon and oxygen. Moreover, the carbon and oxygen stoichiometric ratio can be within a range of 1:0.30 to 1:0.80.

The present invention relates in general to the field of resistive memory elements, and more particularly to resistive memory elements based on doped amorphous carbon, for example resistive random-access memory elements.
Resistive switching refers to a physical phenomenon occurring in a material that suddenly changes its resistance under action of a strong current or electric field. The change is non-volatile and reversible. Several classes of switching materials (ranging from metal oxides to chalcogenides) have been proposed in the past. The performances of these materials are appreciated mainly in terms of power consumption, integration density potential, retention, and endurance. Typical resistive switching systems are capacitor like devices, where electrodes are ordinary metals and the dielectric a resistive switching material, e.g., a transition metal oxide.
An interesting application of resistive switching is the fabrication of non-volatile resistive random-access memories (RRAM), which are promising candidates to replace conventional flash memories as they offer better scalability, higher integration density, lower cost, and lower power consumption. Recently, amorphous carbon (a-C) has been proposed as a resistive switching material for RRAM applications. Compared to oxide-based RRAM, carbon promises higher memory density and lower power consumption. The mono-atomic nature of carbon would make a carbon-based memory cell scalable even to single bonds. Such cell dimensions would limit the reset current, thus reducing the power consumption. In addition, the high resilience of carbon would enable operation at high temperatures.
Another intrinsic advantage of a-C-based RRAM is the switching mechanism. Amorphous carbon is mainly formed by sp2 bonds (conductive) and sp3 bonds (insulating). When a set voltage is applied across the a-C layer, the electric field and the Joule heating induce a clustering of sp2 bonds, bringing the cell into a low resistive state. When another voltage (reset) is applied across the cell, causing a high current to flow through the sp2 filaments, these filaments break down owing to Joule heating, and the cell returns to a high resistance state. No electrochemical reaction is involved: the resistive switching in carbon is unipolar, i.e., the memory can be set and reset by means of voltages of the same polarity. In contrast, resistive switching in oxide-based RRAM occurs owing to the reduction (set) and oxidation (reset) of oxygen vacancies. Therefore, voltages of opposite polarity are needed to set and reset the cell (bipolar switching). Unipolar resistive switching, as it occurs in carbon-based RRAM, simplifies the circuit design of the memory devices, compared to bipolar switching circuits.
Another advantage of carbon-based RRAM is that no "conditioning step" is required. This step is needed in oxide-based RRAM and involves the application of a high voltage across the cell to induce a soft breakdown and form the channel in which the filaments will then grow. Because the conditioning voltage is typically much higher than the set voltage, this step might degrade the device endurance and therefore is not desirable.
To be suitable for RRAM applications, a-C needs to have the right trade-off in the content between sp2 (conductive) and sp3 (insulating) bonds. As one increases the sp3 content, the resistance of the film and the set voltage increase accordingly. This happens because the electric field that is needed to induce the clustering of sp2 bonds is higher. On the other hand, during the reset process, the sp2 filament is surrounded by a high number of sp3 bonds. This guarantees that the reset current flows only along that filament and makes it easier to break the filament down by Joule heating. In general, high resistance (high sp3 content) a-C is needed to provide reversible resistive switching.
The production of high-resistance a-C is not trivial because it requires either special deposition tools or the introduction of certain dopants in the carbon layer. Regarding the first option, it is possible to deposit tetrahedral amorphous carbon (ta-C), which presents a high sp3 content (>70%), by using deposition techniques such as filtered cathodic arc deposition (FCAD) or pulsed laser deposition (PLD).
Another way to increase the electrical resistance of a-C is to dope it with H2, to form sp3 bonds with carbon. It was for instance demonstrated that the resistance of hydrogenated amorphous carbon (a-C:H) could be tuned by seven orders of magnitude by adjusting the H2 content and that the resistive switching in a-C:H is reversible.
Some manufacturers have recently focused their research efforts on developing new carbon-based resistive memories. To resolve the issue of producing high-sp3-content carbon layers, they proposed different approaches, namely to:                use metal electrodes with a steering and a compressive function to increase and stabilize sp3 bonds, also compensating the H2 outgassing in a-C:H;        thermally anneal the carbon layer before depositing the top electrode, eventually, under a UV lamp and in N2, Ar, H2, CO, CO2, He or Xe;        dope carbon with one or more of: H, B, N, Si, Ti and another compound between SiO2, SiON, Si3N4, C3N4, BN, AlN, Al2O3, SiC.
In other approaches, resistive switching has also been reported in graphene oxide and graphite oxide. Graphite oxide is a compound of carbon, oxygen and hydrogen, obtained by treating graphite with strong wet oxidizers. Like graphite, graphite oxide has a layered and planar structure. Each layer consists of carbon atoms arranged in a hexagonal lattice and epoxy, hydroxyl and carboxyl groups bonded to some of the carbon atoms. Graphene oxide is the monolayer form of graphite oxide and is obtained by dispersing graphite oxide in basic solutions.

Resistive memory element based on oxygen-doped amorphous carbon


Electrical components comprising a ohmic contact-providing layer and a charge transport layer wherein the ohmic contact-providing layer comprises a fluorinated carbon filled fluoropolymer.

The present invention relates to an electrically conducting polymer composition or ohmic contact-providing composition comprised of a fluorinated carbon filled fluoropolymer. The ohmic contact is useful as a coating for hole transport layers, and especially, for aromatic amine hole transport layers, reference for example U.S. Pat. No. 4,265,990. In an embodiment, the ohmic contact-providing composition is coated onto a hole transport layer, thereby forming a perfect hole injecting or ohmic contact to that layer. As an alternative embodiment, the ohmic contact-providing composition can be coated onto a supporting substrate, and a transport layer can be coated on the composition. The composition can be selected as an injecting or ohmic contact for holes into materials which are capable of transporting electronic charge. The composition may be useful in any active organic device that depends for its operation on contact to an external circuit where the contact interface does not itself inhibit the supply of charge. The polymer composition ohmic systems, when coated or otherwise deposited onto a hole transporting layer yield the ohmic interface useful for optimum device performance. Further, the polymer compositions of the present invention, in embodiments, will retain ohmic contact with the same transport polymers even after the transport molecules or transport polymers have been rendered conductive by chemical modification. The compositions of the present invention are particularly useful for organic light emitting diode structures, field effect transistors, and any other active organic device that is capable of carrying an electrical current.
Substantial research has been conducted on finding compositions which form ohmic contact layers to media which efficiently transport charge. In general, it is difficult to make stable ohmic contact to organic insulators and semiconductors. Problems encountered in providing an ohmic contact to organic media arise from intrinsic effects like interfacial energy mismatch as well as incompatibilities between the contacting surfaces associated with extrinsic factors like chemical contaminants. When there is such an energy mismatch or electrical incompatibility, the result is a decrease in the efficiency of the interfacial transfer of charge. In these so-called emission limited situations, the contact controls the supply of current which can limit device performance. Therefore, the desired situation is to have a perfect ohmic contact between the current source and the device to which the current is provided in order to obtain a 100% efficient current flow. In the latter case where the contact does not limit the supply of charge carriers to the bulk of the transport medium, the current is said to be bulk controlled.
The compositions of present invention have solved or minimized the above problems by providing an organic composition which, when coated onto or otherwise applied to a transport medium, supplies fully as much charge as the bulk of the transport medium can accommodate under the action of an applied electric field. In embodiments, the supply of electrical current is, therefore, not limited by the contact layer.


A head positioning method controls a position of a servo head from a first arbitrary track position on a disk to a second arbitrary track position on the disk during a seek operation, where the servo head reads a servo signal from tracks formed on the disk. The head positioning method comprises the steps of setting an moving quantity of the servo head, controlling velocity and position of the servo head depending on the initial moving quantity and a difference between a present track position of the servo head and the second arbitrary track position, and ending the seek operation after a predetermined access time elapses from a start of the seek operation when an actual access time is shorter than the predetermined access time. The predetermined access time is preset depending on the initial moving quantity, and the actual access time is a time it actually takes for the servo head to move from the first arbitrary track position to the second arbitrary track position.

The present invention generally relates to methods and circuits for controlling head position, and more particularly to a method of controlling head position in a magnetic disk unit in which a voice coil motor is used to drive a head during a seek operation, and a circuit for controlling the head position in the magnetic disk unit.
When controlling the head position during a seek operation in which a voice coil motor is used to drive the head, it is desirable to move head at a high velocity and to minimize the seek error rate.
FIG. 1 shows an example of a head positioning circuit of a conventional magnetic disk unit. In FIG. 1, a voice coil motor 43 drives a servo head (magnetic head) 42 which reads servo information from a magnetic disk 41, and the head position is determined by the voice coil motor 43. A position signal generating circuit 44 generates a position signal Ps from a signal which is read by the servo head 42, and supplies the position signal Ps to a velocity detection circuit 45, a position error detection circuit 46 and a track crossing pulse generating circuit 47. The magnetic disk 41 is one of a plurality of magnetic disks which are arranged coaxially.
The velocity detection circuit 45 detects an actual velocity Vr from the position signal Ps and a detection circuit Ic which will be described later, and supplies the actual velocity Vr to a velocity error detection circuit 48. The velocity error detection circuit 48 detects a velocity error signal .DELTA.V from the actual velocity Vr and a target velocity Vc, and supplies the velocity error signal .DELTA.V to a power amplifier and switching part 49. A control current Is which is output from the power amplifier and switching part 49 drives the voice coil motor 43 and is detected by a control current detection circuit 50 which generates the detection current Ic described above. This detection current Ic is supplied to the velocity detection circuit 45 as described above and is also supplied to the position error detection circuit 46. The position error detection circuit 46 detects a position error signal .DELTA.P from the position signal Ps and the detection current Ic, and supplies the position error signal .DELTA.P to the power amplifier and switching part 49.
The track crossing pulse generating circuit 47 generates a track crossing pulse from the position signal Ps, and supplies the track crossing pulse to a main control part 51 which is formed from a micro processor unit (MPU). The main control part 51 generates the target velocity Vc depending on a moving quantity of the servo head 42, monitors the position of the servo head 42 from the track crossing pulse, and supplies to the power amplifier and switching part 49 a coarse/fine switching signal which switches the control from a coarse velocity control to a fine position control in a vicinity of the target position. The switching part of the power amplifier and switching part 46 switches the velocity error signal .DELTA.V from the velocity error detection circuit 48 or the position error signal .DELTA.P from the position error detection circuit 46 in response to the coarse/fine switching signal, and outputs the control current Is.
The velocity detection circuit 45 and the velocity error detection circuit 48 form a velocity control part. On the other hand, the position error detection circuit 46, the track crossing pulse generating circuit 47, the power amplifier and switching part 49, the control current detection circuit 50 and the main control part 51 form a position control circuit.
When the main control part 51 receives the moving quantity (number of tracks) of the servo head 42, the main control part 51 generates the target velocity Vc which is dependent on the moving quantity and supplies the target velocity Vc to the velocity error detection circuit 48. As a result, the control current Is is supplied to the voice coil motor 43 via the velocity error detection circuit 48 and the power amplifier and switching part 49, so as to drive the servo head 42. When it is detected via the position signal generating circuit 44 and the track crossing pulse generating circuit 47 that the servo head 42 has reached a position in the vicinity of the target position, the power amplifier and switching part 49 is switched to the position control side. As a result, the position control of the servo head 42 is carried out depending on the position error signal .DELTA.P which is output from the position error detection circuit 46, and the servo head 42 is positioned to the target track.
The above described head positioning control is carried out by the procedure shown in FIG. 2. When the seek operation is started in FIG. 2, a step S1 sets the moving quantity of the servo head 42. A step S2 starts the velocity control of the servo head 42, and a step S3 decides whether or not the velocity control is ended. When the decision result in the step S3 becomes YES, a step S4 starts the position control of the servo head 42. A step S5 decides whether or not the position control is ended, and the process ends when the decision result in the step S5 becomes YES.
However, when the position control of the servo head 42 is carried out in the magnetic disk unit, the resonance of the servo head 42 may occur. The conventional positioning control circuit delays the access time with respect to a seek instruction which is received within a predetermined time after the resonance of the servo head 42 is detected, and suppresses the resonance by providing a constant resonance attenuation time. For this reason, there is a problem in that the access time is inevitably delayed every time the seek instruction is received within the predetermined time after the resonance of the servo head 42 is detected.
FIG. 3 shows an example of the scanning locus SC of the servo head 42 when the seek operation is carried out. In FIG. 3, CFS denotes a switching time when the coarse/fine switching signal from the main control part 51 undergoes a transition, t1 denotes a time when the positional error of the servo head 42 falls within a certain range (for example, .+-.3 .mu.m), and t2 denotes a time when the seek operation is ended. For example, the time t2 occurs 1.0 ms after the time t1. As may be seen from FIG. 3, even if a seek instruction is received between the times t1 and t2, the access time is delayed to a time after the time t2 so that the resonance of the servo head 42 is suppressed.
However, although the resonance is suppressed to a certain degree by the provision of the settling time of 1.0 ms, the access time becomes long. Particularly when two seek operations are made immediately after one another, the resonance of the servo head 42 is accumulated, and it takes considerable time for the positional error of the servo head 42 to fall within the certain range.

Method and circuit for controlling head position


A component has at least one MEMS element and at least one cap made of a semiconductor material. The cap, in addition to its mechanical function as a terminus of a cavity and protection of the micromechanical structure, is provided with an electrical functionality. The micromechanical structure of the MEMS element of the component is situated in a cavity between a carrier and the cap, and includes at least one structural element which is deflectable out of the component plane within the cavity. The cap includes at least one section extending over the entire thickness of the cap, which is electrically insulated from the adjoining semiconductor material in such a way that it may be electrically contacted independently from the remaining sections of the cap.

1. Field of the Invention
The present invention relates to a component having at least one MEMS (micro-electromechanical system) element and having at least one cap made of a semiconductor material, the micromechanical structure of the MEMS element being situated in a cavity between a carrier and the cap and including at least one structural element, which is deflectable out of the element plane within the cavity.
2. Description of the Related Art
Components having MEMS elements have been manufactured in mass production for some years for greatly varying applications, for example, in the field of automotive technology and consumer electronics. The MEMS element may be a sensor element having detection means for detecting the deflection of the micromechanical structural element or also an actuator element having drive means for activating the deflectable structural element. The cap protects the micromechanical structure of the MEMS element from environmental influences, such as particles, moisture, and aggressive environmental media. In addition, defined pressure conditions may be produced within the cavity if the cap is installed in a hermetically sealed way.
A concept for a vertical hybrid integrated component is presented in US Patent Application Publication No. 2011/0049652 A1, according to which a chip stack is formed from an ASIC, a MEMS, and a cap. In the method described here, the starting substrate for the MEMS element is bonded onto an already processed ASIC substrate. Only thereafter is a micromechanical structure produced in the MEMS substrate, which includes at least one deflectable structural element. Independently thereof, a cap is structured from a semiconductor material and prepared for the installation above the micromechanical structure of the MEMS substrate, on the ASIC substrate. The cap wafer thus processed is bonded after the structuring of the MEMS substrate onto the ASIC substrate, so that the micromechanical structure is enclosed hermetically sealed in a cavity between the ASIC substrate and the cap.
The component described in US Patent Application Publication No. 2011/0049652 A1 is equipped with a capacitor system, which—depending on the MEMS function—may be used for detecting externally caused deflections of the structural element or also for activating, i.e., for moving, the deflectable structural element. For this purpose, the capacitor system includes at least one deflectable electrode on the deflectable structural element of the MEMS element and stationary electrodes, which are implemented here in a structured metal layer on the surface of the ASIC substrate.


The invention concerns a carrier for Integrated Circuits (ICs). The ICs are carried by a multi-layer board, constructed of individual layers. Some layers carry conductive traces, and the traces are connected together to form a 3-dimensional network connecting the ICs. The individual layers are constructed of a flexible material, which is commercially available in large sheets, thus allowing multiple copies of the trace patterns to be printed simultaneously. The multi-layer board is attached to a standard printed circuit board, by pins which are driven through them both, and soldered into place.

The speed at which microprocessors can execute instructions has increased dramatically in recent years. The increase in speed has been so great that propagation delays in data travelling to and from the microprocessor chip have become a limitation on processor performance.
As an example, the 8080 microprocessor, which was introduced around 1973, commonly operated at a clock speed of 1 MegaHerz (MHz). Each instruction requires between 3 and 5 clock cycles, giving a resulting speed of approximately 200,000 to 300,000 instructions per second. In contrast, a processor of the '486 family, available in 1991, can have a clock rate of 50 MHz. A typical instruction requires about 2.5 clock cycles, resulting in a speed of about 20 million instructions per second. Plainly, this speed is about 100 times faster than that of the 8080 processor.
In order to reduce propagation delays between the microprocessor and associated memory components, developers have devised ways to pack large numbers of ICs onto small carriers. One such carrier is the Multi-Chip Module, or MCM, shown in FIG. 1. The MCM is a multi-layered structure, in which conductors 3 interweave among themselves to interconnect between the ICs and external traces 6. The interweaving can be explained by reference to FIG. 2. Different layers 9 and 12 carry different patterns 15 and 18 of conductors 20. When the layers are assembled, vias 21 connect the patterns, and the assembly provides a 3-dimensional interwoven connection system, which allows any arbitrary point A to connect with any other arbitrary point B, as indicated by dashed path D.
Several types of MCM are in use. One type is constructed of multi-layered printed-circuit boards. The conductive patterns are printed using silk-screen techniques, and have a line width limit of about 0.005 inches (i.e., about 5 mils). (The limit refers to a minimum width of lines: the narrowest line possible is 5 mils. Line width is inversely proportional to interconnect density. The lines are referred to as interconnects, and narrower lines allow more of them to be packed into a given space, thus increasing the density, measured in number of lines per square inch.)
With such a large line width, the density of lines is small, compared to that available in other approaches, as will be seen. However, the cost is relatively low. A single, completed, pattern-bearing layer costs roughly 10 cents per square inch. A 10-layer board would thus cost about $1.00 per square inch.
A second type utilizes ceramic layers on which the patterns are printed by a silk-screen process. The line width is about 5 mils. For single layers in the form of squares about 2.times.2 inches or smaller, the price is roughly $1.00 per square inch. For larger sizes, the price increases significantly.
A third type utilizes copper polyimide layers positioned on top of ceramic layers. The printing process is photolithography, which can provide a minimum line width of less than 1 mil. However, the present cost is roughly $32 per square inch for a four-layer unit.
A fourth type uses silicon layers, with photolithographic printing. The line width can be less than 1 mil, and the cost is about $15 per layer, totaling about $60 for four layers.
The cost estimates given above are approximate, and can vary greatly, depending on numerous factors, such as quantity purchased, previous dealings between the parties, and complexity of the conductor patterns.
In these types of MCM, the cost increases as line width becomes smaller. Smaller line widths are required for higher IC densities. Consequently, as IC densities increase, these types of MCM will impose higher costs.

Interconnection system for integrated circuits


State retention registers for use in low-power standby modes of digital IC operation are provided, wherein: a differential circuit (M1−M3; M1−M4) is used to load the shadow latch from the normal functional latch; the signal (REST, RESTZ) used to restore data from the shadow latch to the normal functional latch is a “don't care” signal while the shadow latch is retaining the data during low-power standby mode; retained data from the shadow latch is restored to the normal functional latch via a transistor gate connected to a node (N10) of the shadow latch where the retained data is provided; a power supply (VDD) other than the shadow latch's power supply (VRETAIN) powers the data restore operation; and the normal functional latch is operable independently of the operational states of the high Vt transistors (M1, M2, M5 and M6; M3, M4, M5 and M6) used to implement the state retention functionality. In addition, an isolation apparatus is provided to retain an output of a logic module while the logic module is powered-down.

The demand for higher clock-rates and lower power supply voltages in digital integrated circuits such as CMOS circuits results in rapidly increasing levels of standby leakage current (i.e., the current consumed by a CMOS circuit when the clock is not active). As an example, multi-million gate I.C.s operating in the Gigahertz region with supply voltages below 1.5V can have standby leakage of 100 mA or higher. This level of leakage current represents a significant problem for portable (battery operated) applications. This problem is conventionally addressed by introducing products that feature state-retentive, low-leakage standby modes.
Most conventional state retention schemes collapse the power supplies partially or entirely while maintaining the state of all the register elements. Upon restoration of the power, all circuit nodes return to their previous state since all nodes can be derived directly from the state of the register elements.
In conventional power-down applications, power supply to circuits can be turned off in order to reduce the standby power consumption. The state retention flip-flops that store the status of operation of the circuit need to store the data in latches with low leakage current during power-down phase. The retention latch (called a shadow latch hence forth) is formed with thick-oxide (low leakage) transistors and is powered by a separate permanent power supply to retain data in power-down or retention mode. Some disadvantages of such a scheme are: the additional circuitry required for such a shadow latch implementation is magnified at chip level when a large number of retention flip-flops are required; generation of additional control signals required to drive the flip-flop in and out of retention mode not only increase the flip-flop area, but also pose routing problems at block level; and additional shadow latch and control circuitry can load the speed-critical path of the flip-flop worsening the propagation delay of the flip-flop.
As mentioned above, some conventional approaches use retention registers (including shadow latches) to retain state while lowering the device leakage. One such scheme has two supplies, a permanent supply for retention and a virtual supply for conventional logic power. Low Vt (leaky) devices are powered by the virtual supply, while High-Vt (low leakage) devices are used for retention and powered from the permanent supply. This architecture has limitations. Both supplies must be present for normal operation. This introduces a physical design overhead of routing an additional power rail to all the registers. Also, minimum operating voltage is limited by the High-Vt devices, effectively prohibiting conventional Vbox-min testing.
It is desirable in view of the foregoing to provide state retention registers which avoid the aforementioned disadvantages of conventional approaches. The various disadvantages of the conventional approaches can be avoided by various exemplary embodiments of the present invention, wherein: a differential circuit is used to load the shadow latch from the normal functional latch; the signal used to restore data from the shadow latch to the normal functional latch is a "don't care" signal while the shadow latch is retaining the data during low-power standby mode; retained data from the shadow latch is restored to the normal functional latch via a transistor gate connected to a node of the shadow latch where the retained data is provided; a power supply other than the shadow latch's power supply powers the data restore operation; and the normal functional latch is operable independently of the operational states of the high Vt transistors used to implement the state retention functionality. In addition, an isolation apparatus is provided to retain an output of a logic module while the logic module is powered-down.

Retention register for system-transparent state retention


A book forming and pressing machine includes a reshaping device to perform a shaping operation on a book block, a pressing device having a number of spaced-apart pressing plates and burn-in rails to press the book block during the shaping operation, and a loading device that includes a loading table. The loading table includes a book block back support arrangement to support the book block back during the shaping operation. The latter arrangement includes at least one pair of prism plates having shaped upper edges and arranged spaced-apart, extending parallel or quasi-parallel to each other to support a correspondingly shaped book block back during the shaping operation. The arrangement further includes at least one feed element operatively connected with each prism plate and adjustable to a position to support a differently shaped book block back in place of the shaped upper edges of the prism plates.

The invention relates to a book forming and pressing machine comprising a pressing device, a loading device, wherein the loading device includes a loading table and the pressing device includes a number of spaced-apart pressing plates and joint-burning rails. The loading table is equipped with a mechanism that functions to support the book block back and is operatively connected to the shaping operation.
Known book production lines successively combine a book block and a cover in a clocked operation to form a book. A book forming and pressing machine is used for one of the final production steps, for example as disclosed in the German patent document DE 4422783 A1.
The aforementioned document discloses a book forming and pressing machine which comprises a number of pressing devices with thereon arranged joint-burn-in devices, as well as a rotor that is driven intermittently around a vertical axis. The books themselves are supplied via a feed-in station into a pressing device where they are accommodated fully and are formed continuously with the aid of the burn-in rail and remain permanently in the same pressing jaw until they are removed again via the discharge station. Between the feeding in of the book blocks encased in covers and the discharge of the bound and pressed books, the rotor executes some intermittent rotational movements which are utilized as intervals for the pressing and joint burning. In the loading station, the books are divided into the two book flows via a loading rake with associated guide web, so that they are subsequently transported while supported on the side and supported by the loading rake and a counter rake from a loading table equipped with prism bars from below into the opened, stopped pressing device. The prism bars are provided for this with special inserts, designed for round or flat book backs. Format changes for books therefore require machine stops and setup times for replacing the prism plates since the complete machine is provided for safety reasons with a cover which generally has to be removed first. When changing from a flat to a rounded book block back, or when changing to an insert having different dimensions which can be used to achieve a better rounding, the machine must be powered down, the cover opened and the machine subsequently restarted.
With books having a flat or straight back, differently wide support rails are provided as individual bars for which the dimensions are adapted to the thin book format, wherein these bars are screwed immovably into the frame. These are replaced with two straight bars for the wider formats, wherein these are 2 parallel arranged plates for which the narrow longitudinal surfaces point upward once they are fully installed.
According to the prior art, at least one of the plates is installed fixedly in the frame while the second plate can be displaced with the aid of different advancing mechanisms to a defined distance parallel to the first plate. The distance between the two surfaces which point toward the outside corresponds to the book thickness. The book rests with its back on the narrow longitudinal surfaces. With a configuration of this type, thicker books always only rest with the outer region of the book block back on the bars.


A microcontroller has a memory storing a program with an instruction that causes the microcontroller's central processing unit to enter a standby mode, in which data output from the memory is halted. The standby mode is exited by input of an interrupt. The microcontroller also has a control circuit that, by storing the next few program instructions internally before placing the memory in standby, or by delaying the interrupt signal, provides extra time for memory operation to stabilize on exit from the standby mode. Malfunctions on recovery from standby are thereby prevented, and the microcontroller can conserve power by placing the memory in a deep standby mode with a comparatively long recovery time.

The present invention relates to a microcontroller, more particularly to a microcontroller with reduced power consumption.
Referring to FIG. 1, a conventional microcontroller has a central processing unit (CPU) 1 and a read-only memory (ROM) 2. The data stored in the ROM 2 include a program that, when executed by the CPU 1, controls peripheral circuits (not visible) in the microcontroller, enabling the microcontroller to communicate with the outside world and perform various useful functions. Program instructions and other data read from the ROM 2 are passed to the CPU 1 through a data latch 3.
The ROM 2 has an enable terminal (CE) that receives a stop signal (STP) from the CPU 1. While the stop signal is at the low logic level, the ROM 2 is enabled and provides data (DAT) to the data latch 3 in response to address signals (ADR) received from the CPU 1. When the stop signal is at the high logic level, the ROM 2 conserves power by withholding data output. The data latch 3 also receives the stop signal. When the stop signal is at the low logic level, the data latch 3 operates transparently, passing the data (DAT) received from the ROM 2 immediately to the CPU 1. When the stop signal goes high, the data latch 3 holds and continues to output the last data (DAT) received while the stop signal was low. The state in which the stop signal is at the high logic level will be referred below to as a standby mode.
Normally, the CPU 1 holds the stop signal STP at the low logic level and executes instructions read sequentially from the ROM 2. From time to time, the CPU 1 issues a control command to a peripheral circuit, then sets the stop signal to the high logic level, stops program execution, and enters the standby mode to wait for the peripheral circuit to finish processing the command. Power is conserved because the ROM 2 also enters the standby mode.
When the peripheral circuit finishes processing the command, it sends the CPU 1 an interrupt signal (not shown), causing the CPU to resume program execution. Specifically, the CPU 1 reads the instruction held in the data latch 3 and sets the stop signal to the low logic level. The ROM 2 then resumes output of data (DAT) in response to further address signals received from the CPU 1.
Among the types of ROM employed in microcontrollers, one of the most advantageous is flash ROM, which is nonvolatile but can be electrically erased and reprogrammed. Flash ROM has a regular standby mode and a deep standby mode. Power consumption is greatly reduced in the deep standby mode, but recovery from that mode to the normal operating mode takes extra time. If the deep standby mode is employed in a conventional microcontroller, then when the CPU comes out of standby and attempts to read further instructions from the flash ROM, the flash ROM may be unstable and unable to provide correct output. To avoid consequent malfunctions, conventional microcontrollers employ the flash ROM's regular standby mode, which yields a comparatively modest reduction in power consumption.

Microcontroller performing safe recovery from standby mode


A compound type expert system comprising a first fuzzy expert system and a second expert system connected to the first expert system through a calculation control system. The first expert system executes fuzzy rule-based inference according to a first rule set that can describe ambiguity of language information and outputs a definite value. The second expert system executes rule-based inference according to a second rule set that can describe only information without ambiguity of language. The calculation control system is arranged between the first and second expert systems so as to activate the second expert system in response to the definite value output from the first expert system.

1. Field of the Invention
The present invention relates to a compound type expert system which is suitably applicable to a control system for optimization of a plant or an engine, a diagnostic device for a plant, an engine, a vehicle or a computer system, or a backup system for operation of a vehicle, computer equipments or domestic electric devices.
2. Description of the Related Art
An expert system operates with the use of a computer program based on a knowledge base of expert's knowledge in a specific field. Therefore, by using the expert system, even a non-professional can do works as good as an expert does, which increases the application of the expert system since it meets the requirements of upgrading the data-processing quality and decreasing the number of workers or operators.
However, in accodance with the related art expert system, the data of the knowledge base has to be written as definite information without fuzziness and contradiction. Also, it is difficult to write fuzzy information of human feelings such as "young" or "the color is a little thin" in the knowledge base. Accordingly, to make such a fuzzy and complicated decision or dudgement as human feelings, the data amount of the knowledge base becomes very enormous, which makes it difficult to maintain and tune the knowledge base data. This is because that the inference according to the related art expert system ignores the partial satisfaction of required conditions.
On the other hand, there is a fuzzy expert system to which the fuzzy theory is applied to quantify the fuzziness of language information. In accordance with the fuzzy expert system, since it is possible to use qualitative language data, the data amount of the knowledge base can be much reduced. Also, the system admits the partial satisfaction of conditions to make an inference and allows entry of contradictory data in appearece since the system makes a conciliated decision from a plurality of intermediate judgements.
However, in accordance with the inference algorithm of the expert system according to the related art, the final inference result obtained during the process of making the conciliated decision from a plurality of intermediate judgements gives only a qualitative analysis and can not be used as information in the subsequent data processing operation without additional information data of human judgement regarding the result.
For example, in the field of control technique, the information data requires a concrete definite value for control motion such as "set the temperature to be 45.degree. C." or "incline the robot arm by 30.degree. C.". In order to obtain such a concrete data, that is, to make the information not fuzzy, in the fuzzy expert system, a numerical data is calculated from the result of inference with the use of mathematical technique. However, as mentioned above, since the inference result is qualitative, it can not be determined whether the calculated value is reasonable or not.
It is to be noted that the expert system and the fuzzy expert system are disclosed in "Electronic Data Communication Handbook" edited by Electronic Data Communication Society, published by Ohm Co., 1988, Nikkei Electronics, Mar. 21, 1988, and Japanese Patent Application Laying Open (KOKAI) Nos. 63-123177 and 63-123124.


Devices and processes for synthesizing, purifying and analyzing large numbers of compounds for use in combinatorial libraries, are disclosed. The processes involve generating a series of compounds in multi-well plates or multi-tube racks, purifying the reaction mixtures, analyzing the purified compounds, and optionally performing bioassays on the compounds. The information regarding the compounds is stored in a central database. The devices include one or more multi-tube arrays, a purification device, means for transferring the contents of the tubes, a solvent evaporator, analytical instrumentation, and, optionally, a weighing instrument. The multi-tube array(s) optionally include a cover, which can be placed on or removed from the array by computer control. By correlating the orientation of tubes from one stage to the next, it is possible to use a single bar code or other identifying mark for each multi-tube array rather than for each individual tube. This simplifies data collection for large numbers of compounds.

This invention is generally in the area of the synthesis, purification, characterization and assay of combinatorial libraries of compounds.
Before the advent of combinatorial chemistry, the development of new biologically active compounds was dependent on the rational design and synthesis of compounds with a structure similar to existing biologically active compounds. Scientists looked at structure-activity relationships (SARs) to rationally develop a small series of compounds which might be expected to have similar bioactivity. The types of compounds selected for testing typically belonged to narrowly defined chemical classes, such as peptides, steroids, and the like. Such a process is generally known as a rationl approach to synthesis.
The rational approach involved selecting a singular molecular candidate, prepared either via chemical synthesis or isolated from natural sources, and evaluating the molecular candidate for a particular bioactivity. (See, for example, Testa, B. and Kier, L. B. Med. Res. Rev. 1991, 11, 35-48 and Rotstein, S. H. and Murcko, M. A. J. Med. Chem. 1993, 36, 1700-1710.) The cycle was repeated until a molecule possessing the desirable properties was identified. The rational approach was necessary because the synthesis, purification, and evaluation of potential lead compounds was time consuming, labor intensive, and expensive.
One relatively new approach for identifying biologically active compounds is known as combinatorial chemistry. In this approach, libraries of compounds with structures similar to the existing biologically active compound are prepared in small quantities, but in large numbers, and the entire library can be evaluated, for example, using various binding studies.
Many useful drugs have been discovered through the screening of randomly chosen compounds rather than through the rational approach. Combinatorial libraries of randomly-built chemical structures are routinely screened for specific biological activity. (Brenner, S. and Lerner, R. A. Proc. Natl. Acad. Sci. USA 1992, 89, 5381). Rapid screening allows one to evaluate combinatorial libraries, as well as large numbers of compounds, related or not, whether or not they are produced through chemical synthesis or isolated from natural sources, or by using the rational approach.
Both solid phase and solution phase chemistry have been used to develop combinatorial libraries. Solid phase combinatorial chemistry has been used, for example, to prepare oligonucleotide and peptide libraries. A limitation of solid phase chemistry is the scale at which it can be performed. Solution phase chemistry is applicable to a wider variety of chemical reactions, and is more amenable to scaleup, other than solid phase chemistry.
A limitation with combinatorial chemistry is not only in generating new compounds, but purifying, analyzing and screening the compounds. Often, so many compounds can be synthesized that a bottleneck is created at the purification, chemical analysis, and bioassay stages.
Several methodologies have been developed to synthesize, purify, analyze and screen combinatorial libraries. Some of these involve preparing compounds in multi-well plates, and others involve multi-tube arrays. A limitation of using multi-well plates is that it the scale of the reactions tends to be rather limited due to the size of the wells, and it can be difficult to determine chemical yield, since it is difficult to obtain the weight of individual samples in a plurality of wells. Synthesizing compounds in multi-tube arrays allows one to scale up the synthesis somewhat, but suffers from the disadvantage that the tubes are not fixed in position, so that human error can occur if the tubes are misplaced.
Further, there is little standardization in the combinatorial chemistry field. For example, multi-tube arrays often include 48 or 96 tubes. However, automated purification and chemical analysis equipment is not necessarily designed around the number of tubes in the multi-tube arrays used to prepare the compounds. This makes it difficult to track the identity and properties of compounds as they progress through stages of synthesis, purification and chemical analysis.
Prior attempts at overcoming these limitations have typically involved placing individual labels eg., bar codes on each tube in a multi-tube array. The bar codes allow one to keep track of tubes which might have been misplaced due to human error, and also to keep track of tubes moved to and from different multi-tube racks with varying numbers of tubes per rack.
An example of a combinatorial approach that uses bar codes to track the synthesis, purification and chemical analysis of libraries of compounds is a system developed by MDS Panlabs. This system synthesizes compounds at a 1 mmole scale in multi-tube arrays, subjects the compounds to preparative scale HPLC, and analyzes the compounds by flow inject mass spectrometry. Each tube in the array is identified with a bar code, and is moved from stages of synthesis, purification and chemical analysis using robotic arms. The bar codes are typically attached using an adhesive, which can evaporate at any stage when the tubes are subject to conditions involving increased temperatures and/or reduced pressures.
Given the size of many combinatorial libraries, it may be a tremendous burden to place, and keep track of, individual bar-codes on a plurality of tubes. It would be advantageous to provide new devices and processes for analyzing and screening large numbers of compounds without the need to generate bar codes for each tube used to synthesize, characterize or otherwise handle the compounds. The present invention provides such devices and processes.
The present invention is directed to devices and processes for synthesizing, purifying and analyzing large numbers of compounds, in particular, those generated for use in combinatorial and lead optimization libraries.
The processes involve generating a series of compounds in multi-well plates or multi-tube racks, storing the location of the individual tubes in a computerized device, transferring the contents of each tube to a chromatographic device for purification/characterization, removing the solvent from each eluted fraction containing the compound of interest, chemically analyzing the compounds, and then optionally submitting them for bioassays, while maintaining the ability to correlate the position of the tubes in the original multi-well plate or multi-tube array to the position of the tubes generated or used in the next stage of the operation.
The devices include one or more multi-tube arrays, a chromatographic or other purification device, means for transferring the contents of the tubes to the purification device, a solvent evaporator, means for adding solvent to the solvent-evaporated tubes, analytical instrumentation, and a means for transferring some or all of the contents to, and optionally from, the analytical instrumentation. Optionally the devices include a weighing instrument.
In one embodiment, the multi-tube array(s) include a cover, which may be placed on or removed from the array by computer control. This permits the computer to move tubes from the multi-tube array to other locations, such as a weighing station, and also protects the tubes from being moved manually. This overcomes the need to place a bar code on each tube to minimize the types of human error which result in misplaced tubes, and minimizes the error associated with evaporation of adhesives on the bar code label, which can often be greater than ten percent of the weight of the sample.
In some embodiments, the number of tubes in the multi-tube arrays in each step is constant. Alternatively, the number of tubes can vary from one stage to the next. However, a correlation between the orientation of the tubes from one stage can be made with the orientation of the tubes in a subsequent stage.
By correlating the orientation of tubes from one stage to the next, it is possible to use a single bar code or other identifying mark for each multi-tube array rather than for each individual tube. This simplifies data collection for large numbers of compounds.
Compounds which can be evaluated using the process and methods described herein include, for example, pharmaceutical compounds and agricultural chemicals, such as insecticides, pesticides, and herbicides.
In one embodiment, the compounds are arranged in the multi-tube arrays in the form of arrays of different chemical compounds with a common structure, and are each modified in a controlled fashion to create a combinatorial library of structurally related compounds. The common structure preferably has one, and more preferably, at least two sites capable of undergoing a reaction to change the structure, usually by the addition of other molecules.
In one embodiment, the compounds are not synthesized using the devices and processes described herein, but are purified, analyzed and optionally subjected to bioassays after having been previously prepared.
The steps described above can be carried out globally on the array or individually on each tube. For example, during the synthesis step, reagents can be added globally to each of the tubes. During the purification step, the contents of the tubes can be individually transferred to a purification device. When the solvent is removed from the tubes, the entire rack can laced in a solvent removal device. When the reaction products are characterized, the contents of each tube can individually be sent to analytical instruments. Depending on the particular device which is used, those of skill in the art can readily optimize the process by performing certain steps globally and certain steps individually on the tubes in the arrays.

Method and apparatus for synthesizing characterizing and assaying combinatorial libraries


A system for providing field deployable electrical power distribution is provided. The system includes a plurality of power sources providing electrical power to meet the electrical needs of a field operations camp. The power sources include at least one regenerative fuel cell that is arranged to provide a electrical power when renewable energy sources are unavailable. Also provided is at least one generator and one regenerative fuel cell electrically connected to the plurality of loads. Also provided is a plurality of power converters, each of the plurality of power converters being electrically connected between the at least one generator and regenerative fuel cell and one of the plurality of loads. An arrangement is also included for providing a high availability battery charging station.

With the collapse of the Soviet Union, the government officials who operated the former communist state allowed the global proliferation of modern military equipment by selling off equipment through alternative channels of commerce. Through these black-market channels, even insignificant warlord chieftains and terrorists were granted access to weaponry that can disrupt the operations of some of the world's most sophisticated armies. In October 1993 U.S. Army Rangers raided a compound in Mogadishu, Somalia. The U.S. was responding to seizures of humanitarian supplies by local militia who were seeking to exploit the charity of the international community for their own pecuniary gain. During the raid, the militia's forces fired a surface-to-air missile, downing a U.S. Blackhawk helicopter. As a result, U.S. Army commanders redirected foot soldiers and mechanized forces to aid the injured pilots.
During the midst of a firefight and with enemy forces closing in on the helicopter's debris, commanders needed to rely on paper maps and surveillance video to generate routes to the injured pilots. The commanders radioed turn-by-turn directions to the soldiers only to discover that many roads along the routes were impassable due to enemy obstructions. In the ensuing battle-lasting fewer than 24 hours—the U.S. lost two more Blackhawk helicopters and suffered 18 casualties.
To avoid such situations in the subsequent missions, military planners took advantage of advancements in technology to provide soldiers, and their commanders access to an unprecedented amount of information. Some of the information is now collected in real-time using computers, sensors and communications equipment carried by each soldier in the field.
This so-called "integrated soldier technology" created a system that meshes each soldier into the digitized battlefield as a "weapons system" in his own right, each man-platform contributing to the larger, network enabled environment where each soldier platform becomes a key component within the network centric battlefield system. Enhanced communications capability including voice, data, images and internet facilities is now available to each member on the battlefield. The system provides adequate bandwidth for the transfer of large volumes of tactical information. This technology combined with softer camouflage textiles will provide durability, environmental protection and reduced thermal signature.
In addition to its role as protective gear, the modern soldier's helmet has a computerized display that enables the user to view the weapon's mounted sight as well as computer generated images. Together with alternative displays such as weapon mounted sights and hand held computers these elements provide remote viewing of mission critical data including maps, images and video from stored or real-time sources. These remote sources could include weapons sights from other section members, ground sensor pictures sent directly from unattended sensors or from their commanders, or surveillance cameras mounted on unmanned aerial or ground vehicles. GPS systems are combined with navigation sub-systems, to provide fully integrated navigation, orientation and target acquisition capability. The soldier can plan a route in advance, incorporating waypoints and avoiding dangers, using helmet mounted display with visual or audible cues.
Through the use of advanced communications equipment carried by the individual soldiers, additional benefits are also gained. A common problem encountered by modern armed forces during the confusion of battle, as evidenced during the Gulf War, is the phenomenon known as "friendly fire" in which forces accidentally fire on their own troops causing unnecessary casualties and fatalities. Instances of friendly fire often involve aircraft or helicopters accidentally firing on their own ground troops. By combining the communications capabilities with the GPS systems, commanders, pilots and individuals can avoid mistaking their fellow troops as the enemy.
Using this advanced technology, the military planners hope to avoid or stop situations such as that which occurred Mogadishu. However, the additional capabilities come at a price. The equipment and supplies carried by the average soldier, currently weigh nearly 80 lbs. For an average three day mission requires that the soldier carry 20 lbs to 30 lbs of batteries. This added weight has a detrimental effect on the mobility of soldiers.
While existing power systems are suitable for their intended purposes, there still remains a need for improvements in providing a reliable, light weight and field deployable power systems to provide military field operations with the electrical power to complete their missions and allow access to recharging facilities that minimize the need to carry large amounts of batteries. In particular, a need exists for a topology for a power system that provides a means for continuously providing power for recharging batteries when natural resources are unavailable.

Field deployable power distribution system and method thereof


A method of dangling reference detection and garbage collection of VHDL objects within a program includes the steps of providing an Access Value having an Object Reference pointing to an Allocated Object and having and an Access Count pointer pointing to an integer object named Access Count which models a shared access count for the access values. The method sets the Object Reference and the Access Count pointer to null when constructing a new access value and enables an assignment of a negative Access Count to the shared access count when de-allocating a pointer to the Allocated Object. The method also maintains an exact count of a number of pointers pointing to the Allocated Object.

1. Technical Field
The present invention relates to the field of dangling reference detection and garbage collection, more particularly, to dangling access values and garbage collection of objects in a simulation environment.
2. Description of the Related Art
A logic simulator is a software tool, which is capable of performing functional and timing simulations for digital electronic designs which are written in a hardware description language such as Very High Speed Integrated Circuit Hardware Description Language (VHDL) or Verilog. VHDL, for example, permits hardware designers to define signals at a very high level of abstraction. The abstracted signal representations can be translated to actual pins on a microchip using any of a variety of commercial electronic design automation (EDA) software tools.
VHDL provides a measure of flexibility by allowing hardware designers to declare signals of various user-defined types. A user-defined type can either be a scalar or a composite type. Scalars further can be subdivided into four different types, namely enumeration, integer, floating point, and physical. Composites, however, can be subdivided into two types: arrays and records. Still, other defined types include access types and file types.
Scalar and composite types are generally used to represent either single data items or regular collections of data. In some applications such as simulation programs, collections of data of unknown size might need to be stored. Scalar and composite types are insufficient when data objects need to be created as required during a simulation and where links between the data objects need to be represented. In VHDL, access types are primarily used for this function.
In VHDL, access types are used mainly in high-level behavioral models. Access types support dynamic allocation of objects, which is very useful for writing testbenches. An access type in VHDL is like a pointer type found in many programming languages. An access value is like a pointer in VHDL, which points to a dynamically allocated object in VHDL. In VHDL, unlike high level programming languages like C++, an access value can only point to a dynamically allocated object. In particular it can not point to an object created by an object declaration such as a variable declaration.
Although several garbage collecting techniques are known and used by high level programming languages such as JAVA and C++ or in operating systems, such existing techniques will be either inefficient or would render many runtime applications useless in practical terms when used in an HDL Simulation environment. For example, the existing techniques for garbage collecting would utilize excessive amounts of CPU resources to allow a simulation program to operate effectively.
Thus, a technique and system is needed in simulation programs and other programs that efficiently detects dangling references as well as memory leaks and efficiently performs garbage collection of objects.

Dangling reference detection and garbage collection during hardware simulation


A method for testing a plurality of DUTs using a plurality of DC instruments and a pulsed instrument includes contemporaneously applying DC signals to the DUTs with respective DC instruments and sequentially performing pulsed measurements on the DUTs with the pulsed instrument.

The present invention relates to the testing of semiconductor devices and, in particular, to the use of pulsed testing.
Testing of semiconductor devices, e.g., field effect transistors, presents ever increasing challenges. Geometries shrink, complexity increases, power density increases, speed increases and new materials and manufacturing processes are introduced.
Old testing methods are often unsatisfactory in light of these developments. New methodologies are needed to provide the metrics necessary for the implementation and monitoring of these advances.


A method for driving a pixel matrix is provided, and the pixel matrix includes multiple sub-pixels arranged in a matrix. Voltages applied along any one of data lines change in polarity once every four sub-pixels or every two sub-pixels, any one of the data lines controls voltage inputs of sub-pixel respectively connected to two sides thereof or controls voltage inputs of two sub-pixels both connected to one side thereof. The method includes: receiving an image data and acquiring original pixel data according to the image data; generating a first driving voltage and a second driving voltage according to the original pixel data; and loading the first driving voltage or the second driving voltage to the pixel matrix along any one of the data lines. The invention also provides a display device corresponding to the method. The invention can avoid crosstalk, bright dark lines and improve display effect.

VA type liquid crystal panels are widely used in current display products. At present, VA type panels are mainly divided into two types, one is Multi-domain Vertical Alignment (MVA) type, and the other is Patterned Vertical Alignment (PVA) type. The principle of MVA technology is to add protrusions to form multiple visible areas. The liquid crystal molecules are not completely vertically aligned in the static state, and the liquid crystal molecules are horizontally arranged after the voltage is applied, so that the light can pass through the layers. PVA is an image vertical adjustment technology that directly changes the structure of the liquid crystal cell, so that the display performance can be greatly improved to obtain brightness output and contrast superior to MVA.
However, in the existing 4-domain VA technology, with the adjustment of the viewing angle, the structure of the VA-type liquid crystal display panel is prone to color washout at a large viewing angle, so that the displayed image is easily distorted, especially the performance of the character's skin color tends to be lighter blue or brighter white. See FIG. 1, as the viewing angle increases (0°, 45°, 60°), the color washout phenomenon becomes more serious. In the 4-domain arrangement, the sub-pixel polarity is affected, which causes crosstalk and bright dark lines, and the display effect is poor.

Method for driving pixel matrix and display device

XIANYANG CAIHONG OPTOELECTRONICS TECHNOLOGY CO., LTD


Acrylic copolymer PSA compositions having enhanced peel strength without substantially decreasing shear properties have been formulated by producing the copolymer with a broad molecular weight distribution such that the ratio M.sub.w /M.sub.n is above 6, preferably above 10. The alkyl (meth)acrylate and (meth)acrylic acid monomers are emulsion polymerized over a temperature profile wherein the difference between the maximum and minimum polymerization temperatures is at least about 40.degree. C. and less than about 70.degree. C., preferably using a redox initiator system such as bromate/bisulfite.

According to the "Glossary of Terms Used in the Pressure Sensitive Tape Industry," a pressure sensitive adhesive (PSA) is a material which is aggressively and permanently tacky, adheres without the need of more than finger pressure, exerts a strong holding force, and has sufficient cohesiveness and elasticity that it can be removed from substrates without leaving a residue.
Low T.sub.g acrylic copolymers are being used as PSAs. Such copolymers have usually been prepared by emulsion polymerization of acrylic monomer mixtures through free radical initiation. Copolymers made by this process usually have molecular weight distributions, M.sub.w /M.sub.n, in the range of 2-4 as measured by gel permeation chromatography (GPC). While the resulting adhesive is often satisfactory to obtain certain properties, such as tackiness and peel strength on substrates such as polyester or stainless steel, certain properties are generally found to be deficient, particularly the holding power on these same substrates. Previously, increasing the peel strength of acrylic copolymers to a value greater than 2.0 pounds per inch generally caused the holding power (1 kg over one inch square on stainless steel) to diminish to below 40 hours. Attempts to increase the holding power to over 40 hours, however, resulted in a peel strength lower than 2.0 pounds per inch. In practical applications, it is desirable to maintain a high holding power while improving the peel strength, particularly when the PSA is to be used to prepare an adhesive tape.
Various polymerization techniques have been attempted to prepare satisfactory acrylic polymer emulsions. For example, in Japanese Patent J-51125472, a petroleum resin emulsion is obtained by polymerizing vinyl monomers in the presence of petroleum resins having softening points of from 40.degree. to 160.degree. C., an average molecular weight of 300 to 3000, and an acid value and saponification value of less than 1. The monomers include, for example, alkyl (meth)acrylates, vinyl acetates, vinyl chlorides, styrene, acrylonitrile, and acrylic acid. The emulsified mixture is then reacted in an emulsion polymerization reaction to form a shelf-stable emulsion adhesive. The resin emulsion produced is described as having fine particle sizes and ample stability and when cured, the films produced have excellent water resistance and gloss.
Also, U.S. Pat. No. 4,645,711 to Winslow et al. describes the incorporation of hydrocarbon resins from many sources, i.e., from hydrogenated resin esters, polyterpene, polymerized alkyl styrene, and polymerized petroleum-derived monomer resins, into PSA tape compositions where the adhesive is a polymerized acrylic emulsion. The patent describes physically mixing the resin with the polymer emulsion.
Numerous approaches have been used to produce resin emulsions. One approach is to dissolve the resin in a hydrocarbon solvent, combine the resin solution and water to form an emulsion, and strip the solvent. Invariably some residual hydrocarbon solvent remains in the finished emulsion which is undesirable in certain applications. This has led to the development of solvent-free dispersions (see U.S. Pat. No. 2,809,948) and emulsions (see U.S. Pat. No. 3,377,298) of petroleum resins. In both of these formulations, ionic emulsifiers have been utilized. In the former, a mixture of cationic and non-ionic surface active agents is used to achieve a resin emulsion, and in the latter an ionic surfactant is used in combination with an aqueous gel of a swelling earth to produce an emulsion paste of a petroleum resin. These resin emulsions have been commercially used to tackify natural rubber, carboxylated styrene-butadiene and acrylic latexes for many adhesive applications.
The art is also replete with various polymerization techniques intended to improve other properties of polymers obtained through either redox initiation or temperature ramping during polymerization. For example, in U.S. Pat. No. 3,700,456 to Smith, there is described the preparation of a photographic silver halide emulsion by emulsion polymerization of acrylate and other unsaturated monomers with a redox initiator wherein the oxidant is bromate or chlorate and the reductant is bisulfate. Other examples of bromate-sulfite, -bisulfite and -metabisulfite polymerization redox initiators are found in U.S. Pat. No. 3,929,751 to Gershberg (polyacrylamide); U.S. Pat. No. 4,748,217 to Malhotra (polytetrafluoroethylene); and U.S. Pat. No. 4,739,008 to Robinson et al. (water-in-oil biphase polymerization).
In U.S. Pat. No. 4,588,791 to Bieringer et al., vinyl chloride was suspension polymerized with an ascending temperature control to produce a polyvinyl chloride said to have a broad molecular weight distribution. The polyvinyl chloride product was said to exhibit improved flowability for injection molding and to produce injection molded articles having smooth, transparent surfaces.
In U.S. Pat. No. 4,536,556 to Tijssen et al., there is described the emulsion polymerization of .alpha.-methylstyreneacrylonitrile copolymers with a free radical initiator and a chain transfer agent wherein the temperature increases over the course of the polymerization. This technique is said to maintain monomer conversion rates at a maximum and to improve heat resistance.
Accordingly, there still remains a need for improvements in the procedures used to prepare an acrylic copolymer in the form of a latex-like dispersion for application as a PSA having increased peel strength without serious decrease in shear. As mentioned above, there has generally been a decrease in shear properties associated with modifications made in an effort to obtain an increase of peel strength and tackiness. There is a need to improve the peel strength of PSAs while yet maintaining high shear properties and thus obviating the decline in shear usually resulting from variations intended to increase peel strength.

Adhesive acrylic copolymers with a broad molecular weight distribution


An electroslag refining starter includes a refined disk fixedly joined in a central aperture of a mounting ring. The mounting ring supports the starter in a crucible below an ingot being electroslag refined. The disk is consumed during starting and is replaceable in the same mounting ring for subsequent reuse.

The present invention relates generally to electroslag refining, and, more specifically, to electroslag refining of superalloys.
Electroslag refining (ESR) is a process used to melt and refine a wide range of alloys for removing various impurities therefrom. U.S. Pat. No. 5,160,532-Benz et al. discloses a basic electroslag refining apparatus over which the present invention is an improvement. Typical superalloys which may be effectively refined using electroslag refining include those based on nickel, cobalt, zirconium, titanium, or iron, for example. The initial, unrefined alloys are typically provided in the form of an ingot which has various defects or impurities which are desired to be removed during the refining process to enhance metallurgical properties thereof including oxide cleanliness, for example.
In a conventional electroslag apparatus, the ingot is connected to a power supply and defines an electrode which is suitably suspended in a water cooled crucible containing a suitable slag corresponding with the specific alloy being refined. The slag is heated by passing an electric current from the electrode through the slag into the crucible, and is maintained at a suitable high temperature for melting the lower end of the ingot electrode. As the electrode melts, a refining action takes place with oxide inclusions in the ingot melt being exposed to the liquid slag and dissolved therein. Droplets of the ingot melt fall through the slag by gravity and are collected in a liquid melt pool at the bottom of the crucible. The slag, therefore, effectively removes various impurities from the melt to effect the refining thereof.
The refined melt may be extracted from the crucible by a conventional segmented, cold-wall induction-heated guide (CIG). The refined melt extracted from the crucible in this manner provides an ideal liquid metal source for various solidification processes including, for example, powder atomization, spray deposition, investment casting, melt-spinning, strip casting, and slab casting.
In the exemplary electroslag apparatus introduced above, the crucible is conventionally water-cooled to form a solid slag skull on the surface thereof for bounding the liquid slag and preventing damage to the crucible itself as well as preventing contamination of the ingot melt from contact with the parent material of the crucible, which is typically copper. The bottom of the crucible typically includes a water-cooled, copper cold hearth against which a solid skull of the refined melt forms for maintaining the purity of the collected melt at the bottom of the crucible. The CIG discharge tube below the hearth is also typically made of copper and is segmented and water-cooled for also allowing the formation of a solid skull of the refined melt for maintaining the purity of the melt as it is extracted from the crucible.
A plurality of water-cooled induction heating electrical conduits surround the guide tube for inductively heating the melt thereabove for controlling the discharge flow rate of the melt through the tube. In this way, the thickness of the skull formed around the discharge orifice in the guide tube may be controlled and suitably matched with melting of the ingot for obtaining a substantially steady state production of refined melt which is drained by gravity through the guide tube.
In order to achieve steady state operation of the electroslag refining apparatus, the apparatus must be suitably started without introducing undesirable contamination or impurities. In a conventional cold start method, a solid starter plate is fixed into position at the bottom of the crucible and above the discharge guide tube.
Conventional slag in particulate form is deposited atop the starter plate around the electrode. An electrical current is passed through the electrode to the starter plate and then through the atmosphere to cause an electrical arc to jump therebetween. The heat from the arc melts the surrounding solid slag. When sufficient slag is melted, the electrode is lowered into the slag to extinguish the arc, at which time power to the electrode effects direct resistance heating of the slag pool for increasing its temperature.
The heated slag pool then continues to melt the tip of the electrode and the starter plate until a hole is melted through the starter plate and liquid metal fills the crucible atop the guide tube. The hole through the starter plate enlarges until it reaches the outer perimeter of the plate, and resulting refined metal and slag skulls line the crucible and the guide tube. Steady state operation is reached when the rate of melting of the electrode and discharge flowrate from the guide tube are substantially equal.
The starter plate is formed of the same material as the ingot electrode except that it has been pre-refined and suitably machined for integral assembly into the electroslag refining apparatus. It is therefore expensive.
For example, the starter plate may be cut from a billet formed by ESR. Since the refined alloy is typically a superalloy, it is extremely strong and difficult to machine. Accurate machining is required, however, to properly assemble the starter plate at the bottom of the crucible in a close-tolerance fit which effects both sealing and good electrical contact with the crucible for carrying the thousands of amps of electrical current during starting.
Accordingly, it is desired to provide a less expensive electroslag refining starter and method of making thereof.


The present invention relates to a process for the production of ethylbenzene from dilute ethylene streams, especially from mixtures of ethane and ethylene where such mixture is the offgas from a refinery operation, such as a fluid catalytic cracking (FCC) operation and wherein the unreacted ethane from the alkylation reactor is dehydrogenated to produce ethylene which is recycled into the original dilute ethylene stream.

The present invention relates to a process for the production of ethylbenzene from dilute ethylene streams, especially from mixtures of ethane and ethylene where such mixture is the offgas from a refinery operation, such as a fluid catalytic cracking (FCC) operation. The conventional processes for utilizing this type of stream for ethylbenzene production are generally focused on methods of utilizing only the "contained" ethylene. In particular, it has been difficult to upgrade the ethane component in the FCC offgas due to its dilute concentration coupled with the presence of olefinic materials in the mixture. The process of the present invention provides methods for not only converting the dilute ethane component to the more valuable ethylene but also for increasing the concentration of ethylene in the feedstream going to an alkylation reactor, thereby reducing the hydrocarbon throughput to the reactor and providing an efficient process overall. Ethylbenzene is useful for preparing styrene.
Ethylbenzene is usually prepared by the alkylation of benzene with ethylene. Commercial processes include liquid phase alkylation with Friedel-Crafts catalysts, such as aluminum chloride and phosphoric acid or zeolite catalyst, and vapor phase alkylation with acidic carrier catalysts, such as crystalline alumino-silicates. A disadvantage of these processes is that they require an essentially pure stream of ethylene. Typically, polymer grade ethylene is used to alkylate benzene in an alkylation reactor. Such polymer grade/pure ethylene is expensive to produce.
Ethylene is primarily obtained from the thermal cracking of saturated hydrocarbons, such as natural gas rich in ethane, propane and n- and iso-butane. Ethylene may also be obtained from the thermal or steam cracking of naphtha. A disadvantage of cracking is that other products are also produced, including diolefins and acetylene which must be separated from the ethylene, and such separations are costly and significantly increase the cost of producing ethylbenzene. Separation methods include extractive distillation and/or selective hydrogenation of the acetylene back to ethylene. Such separation methods may include cryogenic separation of ethylene from acetylene. A typical ethylene separation section of an ethylene plant utilizes a complex sequence of cryogenic and fractionation steps.
U.S. Pat. No. 5,138,113 discloses a two-step cracking-alkylation process for production of alkylaromatic hydrocarbons from natural gas containing mostly methane, the process comprising: 1) thermal cracking of the natural gas with formation of hydrogen and C.sub.2 -C.sub.3 hydrocarbons, particularly, ethylene and acetylene; 2) separation of the C.sub.2 -C.sub.3 hydrocarbons, particularly the ethylene and acetylene, by cooled adsorption in a solvent, and 3) conversion of the C.sub.2 -C.sub.3 hydrocarbons from step (2) into alkylaromatics. This type of process leads to the production of alkylaromatic mixtures, primarily alkyltoluenes, which may be useful for premium gasoline blending but are not necessarily useful for preparing for a high purity chemical grade ethylbenzene as a single major product.
U.S. Pat. No. 4,524,230 discloses a method for preparing alkylaromatic compounds comprising a one-step cracking-alkylation process using a paraffinic hydrocarbon as a source of an alkylating agent. The process comprises cracking a paraffinic hydrocarbon into olefinic products on the surface of a non-acid catalyst comprising a metal from group VIII of the Periodic Table which may be supported on a nonacid-acting support in the presence of an aromatic compound. To prepare ethylbenzene, however, this process requires propane as a feedstock which must be decomposed on the surface of the catalyst to generate fragmented alkylating agent, i.e., ethylene. On the other hand, the FCC offgas usually contains only a minute amount of propane, and the process of the present invention does not require propane as an alkylating agent nor desire the fragmentation of propane or any other paraffins to occur during the alkylation reaction.
One method of reducing ethylene costs is to alkylate with dilute ethylene streams, which are available from most refinery FCC units. U.S. Pat. No. 4,107,224 discloses the vapor phase alkylation of benzene to ethylbenzene using a ZSM-5 zeolite as the catalyst. It is taught that the catalyst can handle feedstreams containing from abut 15 to about 20 weight percent ethylene while yielding an ethylbenzene purity of greater than 97 weight percent.
While this reference process shows that the contained ethylene can be alkylated in a vapor phase reactor using a zeolite catalyst, it does not teach conversion of the ethane component in a dilute ethylene stream. The diluents such as ethane and methane are used to control temperature of alkylation reactions, and then purged out for use as fuel.
U.S. Pat. No. 5,430,211 discloses a two-step process of preparing ethylbenzene or substituted ethylbenzenes. The process uses as raw materials, ethane and benzene or substituted benzene and comprises dehydrogenating ethane using a mordenite zeolite catalyst to produce a dilute stream of ethylene, and thereafter, alkylating benzene or substituted benzene with the dilute ethylene stream to yield ethylbenzene or substituted ethylbenzene. The dehydrogenation step comprises contacting an ethane feedstream with a catalytic amount of a dehydrogenation catalyst in a dehydrogenation zone under reaction conditions such that a dehydrogenation product stream containing predominantly ethylene and unreacted ethane is formed. The examples of ethane sources given are natural gas or naphtha. In the second step, the dehydrogenation product stream, with essentially no further purification or separation, and a benzene co-feed are contacted with a catalytic amount of an alkylation catalyst in an alkylation zone under reaction conditions such that ethylbenzene is produced. The catalytic dehydrogenation step is said to produce ethylene in high selectivity without the formation of unwanted impurities, such as acetylene and diolefins. The dehydrogenation product stream which contains predominantly unreacted ethane and a dilute concentration of ethylene can be fed without further purification or separation directly to the alkylation zone. The alkylation product stream is separated via fractional distillation, and unreacted ethane can be recycled to the dehydrogenation zone. It is stated that an advantage of the process is that it does not require a thermal cracker or expensive separation technologies. However, in order for this process to deliver a dilute ethylene stream from the dehydrogenation step without purification to the alkylation step, the conversion of ethane in the dehydrogenation step has to be kept relatively low to avoid formation of impurities such as propylene and xylenes. As a consequence, the concentrations of ethylene in the dilute ethylene stream generated are said to be as low as 5 weight percent and the amount of ethane to be recycled becomes correspondingly high; thus its usefulness for commercial application may be limited. Besides, the alkylation catalysts disclosed in this process do not consume ethylene completely and, therefore, an appreciable amount of unreacted ethylene will be recycled back to the dehydrogenation zone unless it is separated from ethane, which is a costly separation. The ethylene recycled to the dehydrogenation zone will reduce the life time of the dehydrogenation catalyst particularly in the absence of aromatic compounds in the ethane feedstream which may help to scavenge ethylene impurity.
U.S. Pat. No. 5,245,099, describes a method of using pressure swing adsorption technology to recover ethylene and heavier components from a hydrocarbon feedstream such as an FCC offgas for use in an ethylene plant. There is no disclosure of using a dilute ethylene/ethane stream to make ethylbenzene.
U.S. Pat. No. 5,365,011 describes a method of separating a gaseous alkene from a gaseous alkane by a pressure swing adsorption process unit alone or in combination with a distillation column wherein the alkene is preferentially adsorbed onto a bed of 4A zeolite at a temperature of abut 50.degree. C. to about 200.degree. C.,

Process for production of ethylbenzene frome dilute ethylene streams


A circuit for driving a hydraulic cylinder of a construction machine includes: a hydraulic pump; a tank; a control valve; a bottom side line; a rod side line; a quick return circuit having a branch line branched off from the bottom side line and led to the tank and a quick return valve which allows hydraulic fluid to be flowed through the branch line only when the control valve is switched to a contraction driving position; and a recycling circuit which supplies a part of return fluid discharged from a bottom side fluid chamber to a rod side fluid chamber of the hydraulic cylinder. The recycling circuit allows the hydraulic fluid to be flowed only from the bottom side fluid chamber into the rod side fluid chamber of the hydraulic cylinder only when the hydraulic cylinder is switched to the contraction driving position.

1. Field of the Invention
The present invention relates to a hydraulic circuit for driving a hydraulic cylinder of a construction machine including a working attachment, such as an excavator, for example.
2. Description of the Background Art
Background art relating to the present invention will be described, showing an excavator shown in FIG. 5 as an example. The excavator includes a lower propelling body 1, an upper slewing body 2 mounted on the lower propelling body 1 so as to be free to slew, and a working attachment 3 attached to the upper slewing body 2. The working attachment 3 includes: a boom 4 capable of being raised and lowered; an arm 5 attached to a tip end of the boom 4 rotatably about a horizontal axis extending in a right-left direction; a bucket 6 attached to a tip end of the arm 5 rotatably about the horizontal axis in a right-left direction; a boom cylinder 7 which is a hydraulic cylinder capable of being expanded and contracted so as to drive the boom 4 in a raising direction and a lowering direction; an arm cylinder 8 which is a hydraulic cylinder capable of being expanded and contracted so as to rotate the arm 5 in a pushing direction, that is, a direction away from the upper slewing body 2, and a retracting direction, that is, a direction toward the upper slewing body 2; and a bucket cylinder 9 which is a hydraulic cylinder capable of being expanded and contracted so as to rotate the bucket 6 in respective directions corresponding to an excavating operation and a dumping operation. Each hydraulic cylinder includes a bottom side fluid chamber for receiving a supply of hydraulic fluid to expand the hydraulic cylinder, and a rod side fluid chamber for receiving a supply of hydraulic fluid to contract the hydraulic cylinder.
The excavator further includes a hydraulic circuit for driving each hydraulic cylinder. The hydraulic circuit includes a hydraulic pump, a tank, and a control valve interposed between the hydraulic cylinder and the hydraulic pump and tank. The control valve has selectable positions: a position for allowing hydraulic fluid to be supplied to the bottom side fluid chamber of the hydraulic cylinder and allowing hydraulic fluid in the rod side fluid chamber to be discharged; and a position for allowing hydraulic fluid to be supplied to the rod side fluid chamber and allowing hydraulic fluid in the bottom side fluid chamber to be discharged, thereby enabling the expansion/contraction operations of the hydraulic cylinder to be controlled.
Each hydraulic cylinder has a difference between a sectional area of the bottom side fluid chamber and a sectional area of the rod side fluid chamber, the difference corresponding to a sectional area of a rod of the hydraulic cylinder. This sectional area difference makes a flow rate of the hydraulic fluid returning to the tank, namely return fluid, from the bottom side fluid chamber during a contraction operation of the hydraulic cylinder be greater than that of the hydraulic fluid supplied to the rod side fluid chamber, thereby involving a problem of increasing pressure loss in a return side fluid passage.
In response to this problem, a first conventional technique described in Japanese Patent Application Publication No. 2002-339904 uses a quick return circuit branched off from a bottom side line of the hydraulic cylinder and communicated with the tank bypassing the control valve. The quick return circuit returns a part of the return fluid discharged from the bottom side fluid chamber during the contraction operation of the hydraulic cylinder directly to the tank, thereby reducing the pressure loss in the return side fluid passage.
The quick return circuit, however, reduces a flow rate of the hydraulic fluid returning to the tank via the control valve, thus increasing a possibility of cavitation in a supply side fluid passage particularly when the hydraulic cylinder is operated in an identical direction to a direction in which gravity acts on the attachment itself. Specifically, for example, when the arm cylinder 8 is driven in the arm pushing direction, or in other words the direction for contracting the arm cylinder 8, from such an attitude that the arm 5 is enfolded, as shown in FIG. 5, or in other words an attitude in which the weight of the arm 5 and the bucket 6 acts on the arm cylinder 8 in a direction for contracting the arm cylinder, a back pressure of the arm cylinder 8 is reduced to make a rod side pressure, that is, a supply side pressure, be negative, thereby generating a possibility of cavitation.
Meanwhile, a second conventional technique described in Japanese Patent Application Publication No. 2004-92247 uses a recycling circuit interconnecting a rod side line and the bottom side line for the hydraulic cylinder to prevent cavitation due to a reduction in the pressure in the supply side fluid passage from occurring. The recycling circuit suppresses the reduction in the supply side pressure by recycling a part of the discharge side fluid to return to the supply side bypassing the control valve. However, it is difficult to apply the recycling circuit according to the second conventional technique directly to the first conventional technique for the purpose of prevention of cavitation in the first conventional technique. If the recycling circuit were added to the first conventional technique to return a part of the return fluid from the bottom side fluid passage to the rod side fluid passage, or in other words if the recycling circuit were simply added to a hydraulic circuit including the aforethe quick return circuit, the fluid supplied to the bottom side fluid chamber for moving the hydraulic cylinder in an expansion direction could return to the tank through the quick return circuit or could be flowed into the rod side through the recycling circuit. This hinders the hydraulic circuit from functioning as a circuit for actually driving a hydraulic cylinder.

Hydraulic circuit for construction machine

KOBELCO CONSTRUCTION MACHINERY CO., LTD.


A medical connector for connecting medical tubing to a catheter includes a connector body and a height compensating foot. The connector body has a catheter leg adapted to connect to the catheter, a medical tubing leg adapted to connect to the medical tubing, and an angular bend intermediate the legs. The height compensating foot is attached to the catheter leg and extends outwardly therefrom at an angle to prevent the connector from rocking and tubing from overhanging a patient's knuckles when connected to the catheter inserted in a patient.

In the medical and surgical fields, intravenous (IV) fluids are generally administered to a patient through a catheter inserted into a vein of the patient. The catheter is typically coupled to an IV connector, which is connected by IV tubing to a container of IV fluid.
Generally the catheter includes an insertion end and a connecting end configured as a female fitting having a diameter substantially larger than the catheter itself. A cooperating connector has a male fitting portion adapted to mate with the female fitting. The female and male fittings are commonly configured as luer lock type fittings. As luer fittings, the male portion of the IV connector has a precise tapered outer surface, and the catheter's aperture has a similarly tapered female bore. When assembled, the tapered male and female surfaces engage in a slip type interference fit to frictionally fit the catheter and connector together. A fastening means is provided to lock the catheter and connector together.
By design, the threaded collar or female catheter has a larger outside diameter than the male connector, catheter and associated medical tubing connected thereby to the catheter. Problematically however, the relatively larger diameter of the connector portion causes the assembled catheter and connector to teeter, or rock, back and forth about the centerline of the connector. This teetering effect can cause patient discomfort, and some loosening of dressings holding the catheter in place, when the catheter is inserted in a patient.
Additionally, this teetering or rocking about the connector can cause in-and-out movement of the catheter tip causing vessel wall damage, or even full infiltration of the catheter tip through the vessel wall.

Angled medical connector with height compensator