A data storage device is provided. The data storage device, which is coupled to a data processing device, includes a memory array partitioning into a plurality of memory banks. The data storage device further includes a bank enable circuit for enabling at least one of the memory banks from the plurality of memory banks of the memory array. The data storage device also includes an operation/pseudooperation enable circuit (OPEC) for generating an operation or a pseudooperation signal to one or more banks enabled by the bank enable circuit. The OPEC has a first input for receiving an operation request signal from the data processing device and a second input. Additionally the data storage device includes a pseudooperation control circuit for controllably generating a pseudooperation request signal to the bank enable circuit and to the second input of the OPEC.

(1) Field of the Invention
The present invention relates to the field of static memories. More specifically, the present invention relates to an apparatus and method for discharging bit lines in a memory device.
(2) Description of the Related Art
Many microprocessors include set-associative level-1 (L1) cache devices to enhance performance. Often, L1 caches implement a "cache-banking" and "stop-clock" scheme to reduce power dissipation. The "stop-clock" mechanism involves halting the toggling of the clock signal, that is routed to various units of the microprocessor including the cache, if those units are not currently used. A set of elaborate conditions are used to detect when the clocks routed to a particular unit of the processor may be safely stopped without causing a malfunction--the details of those conditions are beyond the scope of this discussion.
To facilitate the understanding of the "cache-banking" scheme, which will be explained later in this section, the following discussion uses as a non-limiting example a cache device with the following characteristics: the address bus is 32 bits wide; the cache has 20 tag address bits (address bits 31:12); the cache has 8 set address bits (address bits 11:4) thus cache will have 256 sets; the cache has a line-size of 16 bytes (128 bits), the 4 lowest address bits [3:0] being used to specifically access any of the 16 bytes within a cache line; the cache can have any number of ways (depending on the cache size).
FIG. 1a shows a column of an SRAM cache device. In this cache device, 256 SRAM cells 2 are placed on a same Bitline 4 and Bitline# 6, each SRAM cell having its own Wordline 8. The Bitline 4 and Bitline # 6 are gated as inputs to a sense amplifier 10 which detects differences in a level of voltage between Bitline and Bitline #. A pre-charge circuit 12 pre-charges the Bitline and Bitline # to the same level (VCC-V.sub.tn), during a first half of every clock cycle. A write-control circuit 14 is used to drive the appropriate data values from a Drive Input line 15 along bitline and bitline # during a write cycle.
FIG. 1b shows a gate level representation of a typical SRAM cell. A pair of cross-coupled inverters will store a logic value and respectively, a logic complement of the logic value. The two NMOS transistors 17 and 19 serve as pass gates when a pulse is sent via the wordline 8. Data stored in the SRAM cell is thus read by driving bitline and bitline # with data stored in the SRAM cell.
FIG. 2 shows the structure of a complete data array for an "unbanked" cache using Single Data Bit Array elements "SDBA" elements. An SDBA represents one column of the cache device. Since each cache line has 16 bytes (128 bits), 128 SDBA elements are shown in this figure. A set address decoder 218 decodes the Set address bits [11:4] outputting decoded wordlines WLDEC [255:0]. Only one of the 256 lines is active at any time. A Pulse Timer circuit 220 receives a CACHE.sub.-- CYCLE signal from a processor (not shown). CACHE.sub.-- CYCLE indicates that the cache is currently accessed by the processor. If the CACHE.sub.-- CYCLE signal is active, the Pulse Timer generates, every clock cycle, a pulse of a certain length, after a certain delay, on each of the lines "wordline-pulse" and "sense-amp-pulse." The pulse on the "wordline.sub.-- pulse" line causes an appropriate wordline decoded by the Set Address Decoder 218 to be pulsed.
An AND gate 222 is provided for each wordline of the cache. Each one of the 256 outputs of the Set Address Decoder is coupled to one input of a different gate 222. However, only one of these AND gates 222 will receive a WL.sub.DEC signal set to `1`. The "wordline pulse" line 223 coupled to Pulse Timer 220 is also input to each of the gates 222. Gate 222 generates at its output, which is connected to a wordline 224 of the cache array, a wordline signal WL which replicates the wordline pulse issued by the Pulse Timer if the corresponding wordline decode signal WL.sub.DEC is set to logic 1. In other words, if the address of a specific line has been decoded by the address decoder 218 and a CACHE CYCLE signal is issued by the processor, a selected line of the cache array will be pulsed. In so doing, an operation issued by the processor, such as a "read" or a "write", can be performed upon the cache array when additional signals required for these operations are provided by the pulse timer circuit 220 of FIG. 2. Upon reading or writing from or to a particular SRAM cell, the respective bitline and bitline # coupled to the SRAM accessed by the microprocessor will be discharged. Typically, the bitlines of a static memory, such as the memory shown in FIGS. 1 and 2, act as capacitors and are precharged to a predetermined voltage prior to reading the SRAM cells. The state assumed by the SRAM memory cell is read by applying an input voltage to the selected wordline and sensing which bitline experiences a change in voltage. The state assumed by a selected SRAM memory cell determines which bitline, Bitline or Bitline #, will be discharged towards ground or VSS when the cell is read. A write operation is performed in a similar way by discharging a specific bit line.
Accesses to the cache device are sequenced by a clock generating clock cycles. Each clock cycle can be conceptually divided into two equal phases. The first phase, first half of the clock-cycle, is the precharge phase, wherein the precharge circuitry 12 of FIG. 1 precharges the bitline and bitline# to the same high voltage level (VCC-V.sub.tn) where V.sub.tn is the threshold voltage for the NMOS device used to precharge the two bitlines. The precharger is turned off in the second phase, when one of three following events will occur. One possibility is that no bit is accessed during that clock cycle, the bitline and bitline# remaining precharged at their high levels. The bitlines will not be discharged and, thus, no power will be dissipated. None of the wordlines nor the sense-amp-enable will be activated if no cache access occurs during the second phase. Another possibility is that a particular SRAM cell is written to. In this case the "Write Control Circuit" 14 of FIG. 1a will drive a "1" on bitline and a "0" on bitline# or vice-versa, depending on the value that is written into the SRAM cell. The appropriate wordline, for the correct set, will be pulsed and the correct value will be written in the SRAM cell for that particular set. The sense-amp-enable signal does not need to be activated for a write cycle. Yet, another possibility is that a particular SRAM cell is read from. The appropriate wordline including that SRAM cell will be pulsed, causing that SRAM cell to drive the bitline and bitline#, using the data stored therein. The sense-amp enable line will be pulsed and the sense-amplifier will sense the voltage difference between bitline and bitline# driving thus the correct logic level at the sense-amp output.
In all the cases mentioned above, whenever a high value is driven on bitline and bitline#, that high-value is always driven through NMOS devices via one of the following: the bitline precharger, the SRAM cell itself, or the write control circuit. Accordingly, the high level on either the bitline and bitline# should not exceed (VCC-V.sub.tn). Henceforth, whenever the term "voltage" is mentioned in the context of the sense-amplifier gain, reference will be made to the "inactive" high-voltage level at which bitline and bitline# are found, when there is no cache access and thus no discharge of the bitlines. This voltage level, theoretically, has to be the same as the precharge-level. As it will be further explained, this is not always the case.
As it is apparent from FIG. 3, which illustrates by way of non-limiting example, a plot of a sense amplifier gain versus the above-mentioned "inactive" high voltage, the sense-amplifier has a high-gain region between 1.3 V and 2.2 V. Outside this region, the gain drops off very dramatically. In the particular case, the VCC was at 2.7 V and the (VCC-V.sub.tn) level was within the high-gain region 1.3 V 2.2 V.
In an "unbanked" cache design, all 128 SDBAs will share the same wordlines [255:0] and the same sense-amp enable lines shown in FIG. 1. Since the sense-amp enable of all 128 SDBAs are connected together, the sense-amplifiers in all SDBAs would be turned on as soon as a CACHE CYCLE signal is executed. Therefore, during any cache read-operation wherein a pulse would be sent through one of the wordlines, all the bitlines (and bitlines #) of all 128 SDBAs would be discharged, thereby causing power to be dissipated in all the bitlines of the cache device.
Part of the power dissipated in an "unbanked" cache, when a read/write operation is issued by the processor, can be saved by using a "cache-banking" scheme. FIG. 4a illustrates a banked cache. The "cache-banking" scheme is premised on the fact that in most cache accesses, the micro-processor data-path (computational logic) does not use all the information that is present in a cache line at one time. For example, according to cache-banking scheme shown in FIG. 3, the 16-byte cache-line can be divided into smaller "chunks", each of which can be accessed as an atomic unit. A cache line 308 can be divided into four 4-byte chunks or into eight 2-byte chunks and so on. The granularity of this division depends on factors like the data path width of the microprocessor and on how much power needs to be saved.
Each cache line (16 bytes) in FIG. 4a is thus divided into four 4-byte (32 bit) chunks. Each such chunk will be called hereinafter a "bank." Banks are accessed as follows:
Access Bank 0.fwdarw.(bytes 0,1,2,3 of cache line).fwdarw.bits [31:0] PA1 Access Bank 1.fwdarw.(bytes 4,5,6,7 of cache line).fwdarw.bits [63:32] PA1 Access Bank 2.fwdarw.(bytes 8,9,10,11 of cache line).fwdarw.bits [95:64] PA1 Access Bank 3.fwdarw.(bytes 12,13,14,15 of cache line).fwdarw.[127:96]
The starting address and the length (amount of data to be read/written) of a cache cycle, will determine which of the cache banks should be accessed during a cycle. In all cache accesses, all 4 bytes in each bank are accessed as a group. More than one bank 1 however, can be accessed simultaneously. For example, if the starting address of an 8-byte read access is at byte 4, Bank 1 and Bank 2 need to be accessed. In a banked cache when a microprocessor's control unit sends out the starting address and the length (in bytes) for each cache access, this information is used to intelligently turn on only those banks that are needed for that cycle. Since all the tag and (least recently used) LRU/valid bits for any cache line need to be accessed for any cache cycle, the tag and LRU/valid arrays will not be banked.
As one can see from FIG. 4a, the data array 308 is divided into four banks as explained above. Each bank of the data array 308 has 256 AND gates 322. Each of these gates 322 receive the following inputs: a line WL.sub.DEC from decoder 318, which corresponds to the respective wordline of the data cache array to which gate 322 is coupled at an output thereof; a wordline pulse coupled to pulse timer 320 for coupling a wordline pulse signal to the gate 322; and a bank select Bank.sub.se1 line coupled to a bank select circuit (not shown) for enabling one or more selected banks of the cache data array 308. When a particular bank is selected, then only the appropriate wordline of that particular bank will be pulsed upon the generation of a wordline pulse signal by the pulse timer 320. As one can see, the other remaining three banks will have their Bank.sub.se1 signal set to 0 logic and, thus, the output of gate 322 coupled to the respective un-selected banks will be 0. According to this scheme, even in the instances where the CACHE CYCLE signal, input to the pulse timer 320, is issued by the processor to initiate a cache access to data array 308, the wordlines of non-selected banks of memory will not be pulsed. Thus, in these banks power will not be dissipated upon the access of one of the SRAM cells of a selected bank.
As one can see from FIG. 4a, an AND gate 324 has an output coupled to the sense amplifiers of each bank. Each Bank.sub.se1 signal is coupled to the gate 324 corresponding to the respective bank. Therefore, the sense amplifier corresponding to each bank will only be turned on if both a "Sense Amp Pulse" signal is issued and a bank select signal Bank.sub.se1 is issued.
For example, for accesses which only require Bank 1 and Bank 2 to be turned on, the bitlines in Bank 0 and Bank 3 will not be discharged and similarly the respective sense amplifiers corresponding to Bank 0 and Bank 3 will not be turned on. In this example, the banked-cache scheme can save about half the power that otherwise would be dissipated in an "unbanked" cache data array. If access is needed to only one bank during a certain cycle, the power saved can be even greater. The power saving can increase as the granularity of banking in the cache line is increased, e.g. a cache with eight 2-byte banks would end up saving more power for certain cycles. Another related benefit of using cache-banking is that this scheme reduces the relative frequency of power surges on the chip since not all banks need to be discharged for every cache cycle. This helps mitigating electron-migration problems in silicon. Power surges (high power dissipation) causes high current densities in the metal lines that route VCC, VSS, and other signals throughout the chip. If the incidence of such high current densities become very frequent, it causes those metal lines to become thinner due to migration of electrons ("electron migration"). The lines may ultimately break, causing functional failure. While the cache banking scheme can significantly reduce the power dissipated in a cache memory, static memories suffer from a problem inherent in the structure of these memories. This problem is called "voltage creep" and will be explained in conjunction with the following discussion.
The "bitline creep" is a behavior of a cache device which can be encountered when the voltage on the bitline and bitline# starts "creeping up" above (VCC-V.sub.tn), due to leakage through the transistors in the precharge circuit and write-enable circuit. For each individual clock cycle, the amount of leakage, or the creep in voltage is minuscule. However, if this leakage is allowed to occur over many hundreds clock cycles, the cumulative creep in bitline and bitline# voltages will take these lines out of the "high-gain" region for the sense-amplifier as shown in FIG. 4b. If this occurs, then on the next read-access to the cache, the sharply reduced gain of the sense-amp will cause a much longer delay in generating the sense-amp output. Thus, the sense-amp will output meaningless data for a longer duration before it will be able to successfully detect the differential between bitline and bitline#, and thus send out the correct output data. This delay in sense-amp output generation, will cause many problems such as incorrect hit/miss detection in the tag-comparison logic and setup-time violations in the logic that uses the cache data output.
However, any read/write access operation to the data memory array before its bitline inactive-voltage "creeps" out of the "high-gain" region of the sense-amp can cause the bitline and bitline# to descend to the normal "VCC-V.sub.tn" level, thereby discharging bitline and bitline#. As mentioned before, for a read access, the SRAM cell will actively drive a high value of (VCC-V.sub.tn) on one of the lines, through the corresponding NMOS transistor in the SRAM cell. For a write access, the write-control-logic will actively drive a high value of (VCC-V.sub.tn) on one of the lines, through the corresponding NMOS transistor in the Write Control Circuit. Accordingly, the voltage "creep" problem occurs only if there is a sufficiently long and continuous series of inactive cycles which will allow the bitline and bitline# voltage to creep beyond the high-gain region of the sense-amp.
FIG. 4b shows a graph of bitline-voltage vs. time during a long period of inactivity. This graph illustrates the "voltage creep" in an SRAM device that does not use a "bitline-discharge" mechanism. FIG. 4b also shows how this "voltage creep" problem is alleviated by using a bitline discharge mechanism.
Such mechanism is disclosed in the patent application of Chang, et al. 08/437,090 issued to Intel Corporation of Santa Clara, Calif., which discloses a memory with a bitline discharge mechanism for unbanked caches which do not have a "stop-clock" mechanism. FIG. 5 illustrates some of the salient features of Chang. The circuit illustrated in this figure is used for generating a wordline pulse to an un-banked cache memory (not shown) to avoid the bit line creep problem. The counter 530 is a simple digital up-counter, with a reset gate for receiving a reset signal. Whenever the Reset signal is asserted, the counter starts counting from 0 up to the "Maximum Count Value." As this figure shows, the counter will be automatically reset once the maximum count value is reached. When the counter reaches the Maximum Count Value, an additional bitline discharge is triggered by having the pulse timer 536 issue a wordline-pulse signal. This additional bitline discharge hereinafter will be denominated as a pseudooperation. If a "RESET" signal, due to assertion of "Cache.sub.-- Cycle", is received before the counter reaches the "Maximum Count Value," the counter will be reset starting to count from 0. This counter-driven discharging mechanism for the bitlines causes additional power dissipation. Furthermore, since all bitlines (i.e. the full cache line in the data array) are discharged at the same time, it causes relatively frequent "power surges." This could result in serious electron migration problems in silicon.
Banked cache memories may additionally use a "stop-clock" mechanism for saving power. In this case, even though the cache may be accessed during a particular cycle, not all the banks and, thus, bitlines in the data array may necessarily be discharged if a bitline discharge mechanism such as the one illustrated in FIG. 5 was used. To understand this problem, let us assume that during 100 clock cycles, Bank1, Bank2, and Bank3 of the banked cache device shown in FIG. 3 are frequently accessed, but Bank0 is not accessed at all during this time. In this case, there will be at least one cache access for every 100 clocks and, thus, the counter of FIG. 5 will be reset each time such that the counter will not reach a count of 100 (Maximum Count Value). We will assume that the bitlines will "creep up" beyond the "high-gain" region of the sense-amplifier, during 100 clocks of inactivity required for triggering a bit line discharge within those clocks, because the counter was reset for every cache access to any bank. This would prevent any pseudooperation bitline discharge from occurring in Bank0, causing the bitlines of Bank 0 to remain inactive for 100 clocks. Accordingly, because Bank 0 was not accessed during 100 consecutive clock cycles, the voltage of bitlines in Bank 0 will creep up beyond the "high-gain" region of the sense-amp. Thus, the next read access to Bank0 may encounter a large delay while the sense-amplifier tries to detect the differential between bitline and bitline#. A speed failure would occur if the Chang reference was used in conjunction with a banked cache.
Moreover, the "stop-clock" feature described above complicates the problem even more. Whenever the clock is stopped, the counter in FIG. 5, which runs on the clock, stops counting. Accordingly, if the counter has been stopped due to a stop-clock signal for a time longer than 100 clocks, enough time would elapse to cause the bitlines to creep up to a voltage which is beyond the "high-gain" region of the sense amplifier. It is, thus, possible that an actual cache read access would be issued to the cache memory before the counter reaches its Maximum Count Value and is able to trigger an additional bit line discharge. In this case, the sense amplifier may cause a substantial delay, thereby causing a failure in the operation of the cache memory.
Accordingly, it is desirable to provide for a banked data storage device with a mechanism for providing bitline discharges such that the creep up problem is avoided. Additionally, it is desirable to provide for a bank data storage device having a stop clock feature for saving power such that the voltage on the bitlines will not creep up in cases where the clock is stopped for a period of time longer than the time that generally takes to the bitline to creep up.

Banked SRAM device with bit line refresh


Novel supported catalysts, well adapted for the catalytic conversion of exhaust gases emanating from internal combustion engines, include a porous carrier material, e.g., alumina spheres, such porous carrier material having a catalytically effective amount of at least one non-platinum group catalytically active element, e.g., cerium, essentially homogeneously concentrated throughout the depth of a defined peripheral face surface layer (outer band or ring) thereof.

1. Field of the Invention
The present invention relates to novel supported catalysts and to a process for the production thereof.
By "supported catalyst" is intended a catalyst of porous material, having catalytically active elements deposited onto the surface thereof, particularly by an impregnation process.
This invention especially relates to supported catalysts having at least one catalytically active element deposited onto a portion of a carrier therefor, namely, onto the peripheral outer layer (band or ring) of the carrier (support).
2. Description of the Prior Art
Supported catalysts have long been known to this art and they are useful in many processes, such as treating petroleum cuts or treating effluents, e.g., catalytically converting the exhaust gases emanating from internal combustion engines.
The catalysts typically comprise a carrier produced by shaping a porous material such as alumina. Thus, the carrier may assume various shapes, such as spheres, cylindrical extrusions or extrusions having a polylobal cross-section or a cross-section of various shapes, such as a wheel.
The porous materials generally used are alumina, silica, resin, zeolites or the like.
These carriers generally have a large specific surface area, e.g., over 20 m.sup.2 /g, to provide a large area which is rendered catalytically active by depositing catalytically active elements thereon.
The catalytically active elements may be grouped into several categories:
(i) catalytically active elements proper; these are typically elements of the platinum group of the Periodic Table, such as palladium, rhodium and the like,
(ii) promoting elements therefor, which promote or enhance the catalytic activity of the above elements.
Currently, various elements are typically impregnated onto the entire surface area of the carrier, except for the elements of the platinum group and more specifically the element platinum. It is not possible to control the depth to which the element penetrates into the carrier, or the concentration of that element in each part of the area.
In view of the speed at which the reagents are diffused into the catalyst, it is known to this art that only a peripheral part of the catalyst is effective. Consequently, only a fraction of the elements deposited will actually be catalytically effective.
The catalytically active elements are typically very expensive materials and significantly affect the cost of carrying out a given catalytic process. Attempts have therefore long been made to reduce the amount of catalytically active elements in catalysts, while maintaining a level of catalytic activity which is high and at least equivalent.
One solution to the above problem is described in U.S. Pat. No. 3,674,680 to Hoesktra et al.
This solution entails forming the carrier or catalyst into special shapes, such as to provide a catalyst of a thickness which is no more than twice the thickness of the diffusion layer of the reagents. Thus, the greater part of the catalyst is in contact with the reagents.
However, this limitation on thickness makes it necessary to have complex shapes, resulting in catalysts which are brittle and expensive to produce.
A method has also been proposed to this art for impregnating metals of the platinum group, enabling the impregnation to be carried out solely within a sheath about the periphery of the carrier. The process uses a solution of platinum salt. However, it cannot be adapted to deposit other elements, e.g., transition metals or rare earths.


A device for storage of an uncured rubber product is provided. The device comprised of:. a bobbin composed of two flanges, each equipped with a border support portion fitted on the axially interior side of said flange, the border support portion having the general appearance of a spiral forming several turns, said border support portion being shifted forward, on each turn, axially toward the outside;. an interleaf in the form of an elongated strip, resting on the said border support portions, the interleaf having a variable width, adapted to the axial distance between the said border support portions.

The present invention concerns production of rubber products. More precisely, it relates to storage of uncured rubber products delivered from extrusion.
It is known that, in the non-vulcanized state, rubber presents a rather plastic state. It results that it is very difficult for this material to keep its geometric dimensions unchanged if it is stressed mechanically, for example by materials handling operations. It is thus that it is common usage to use interleaves on which the uncured rubber product to be manipulated is laid. The interleaf is constructed of a material presenting sufficient resistance to elongation. It can be rigid or flexible according to the expected utilization. In all cases, it plays the role of a holder for the uncured rubber material (whose state is plastic) and provides a grip permitting all desired manipulations.
As an illustration of the state of the art, patent application EP 0 567 147 can be cited, illustrating an interleaf used in the tire industry. The latter is shown in the form of an elongated strip, of dimensions which cannot be altered under the effect of stresses from utilization, presenting two border portions intended to protect the product stored between them on the strip. Unfortunately, when it is desired to store the product in bobbins, the proposed solution is somewhat maladapted because the border portions in question, even when cut at regular intervals, inevitably impede flexing of the said strip during winding.

Device for storage of non-vulcanized rubber products on bobbins

Compagnie Generale des Etablissements Michelin-Michelin et Cie


A transmission line substrate includes: a dielectric substrate; a signal line disposed on the upper surface of the dielectric substrate; first and second ground conductors disposed on the upper surface of the dielectric substrate, field-coupled to the signal line, having potentials different from each other; a dielectric film disposed between an overlapping part of the first ground conductor and a part of the second ground conductor at which the first and second ground conductors overlap each other, to constitute a MIM capacitor; a capacitor connected between the first ground conductor and the second ground conductor in parallel with the dielectric film; and a resistor connected between the first ground conductor and the second ground conductor in series with the capacitor.

1. Field of the Invention
The present invention relates to a transmission line substrate having a coplanar line, and more especially to a transmission line substrate that can transmit signals over a broad band.
2. Background Art
A transmission line substrate having a coplanar line has been known (for example, refer to Japanese Patent Laid-Open No. 2000-244209). In some cases, the ground conductor of the coplanar line has two potentials. In this case, in a conventional transmission line substrate, two ground conductors having different potentials were AC-coupled.

Transmission line substrate having overlapping ground conductors that constitute a MIM capacitor


A testing method and apparatus for determining whether surgical cartridges have excess drivers. A blade is disposed in the slots of the cartridge and displaced while it contacts the floor of the slot. If an excess driver is encountered, the blade is displaced away from the floor and this movement is detected, preferably by an electronic sensor. The apparatus includes a base plate to which a carriage is mounted, either directly or through other structural members. The carriage is configured to slide along a pair of parallel shafts, and is driven by a pneumatic ram or other linear prime mover. A tooling plate is moveably mounted to the carriage, and the blade is mounted to the tooling plate. Movement by the blade due to excess drivers results in movement by the tooling plate relative to the carriage, which is detected and recorded, such as by a computer.

1. Field of the Invention
This invention relates generally to an apparatus and a method for testing surgical cartridges into which discrete articles have been inserted, and more particularly for testing whether there are too many discrete articles in a surgical stapling cartridge.
2. Description of the Related Art
In the field of microsurgery, a surgical instrument having a cutting blade traverses a specific path through tissue. One feature of the surgical instrument is a single-use cartridge, shown in FIG. 1, that is a holder for surgical staples. The cartridge is an elongated plastic body with a longitudinal channel that serves as a guide for a surgical blade. The cartridge has rows of small staples on opposite sides of the channel, and these rows are aligned parallel to the guide channel. Drivers are inserted in apertures (also called "pockets") aligned with the rows in order to push the staples out of the cartridge and through the adjacent tissue. Before the blade has made its cut, each side of the incision is stapled together by displacing the drivers relative to the cartridge. This displacement forces the staples against an anvil on the opposing side of the surgical instrument as the cartridge and the anvil deflect the points of the staples into a clasping position.
There may be as many as fifty or more very small staples on each side of a two-inch incision. Each staple can be driven into the tissue to close the incision by the correspondingly small drivers. The task of inserting the drivers into the cartridge is labor-intensive due to the small size and number of the drivers and the apertures.
It is known in the prior art to insert drivers mechanically into surgical stapling cartridges, as shown in U.S. Pat. No. 5,836,147 to Schnipke, U.S. Pat. No. 5,653,928 to Schnipke, U.S. Pat. No. 6,158,205 to Schnipke et al., and U.S. Pat. No. 7,207,168 to Doepker et al., all of which are incorporated herein by reference. Workers manually position the cartridges, as well as the holders that contain the drivers and hold them relative to the machine, in the machines disclosed in these patents, and then actuate the machine to insert the tiny drivers into the pockets in the cartridges. After a fraction of the total number of drivers is inserted by one machine, the cartridge is then manually transported to the next machine, which inserts another fraction of the drivers. In U.S. Pat. No. 6,729,119 to Schnipke et al., which is incorporated herein by reference, a robotic loader is described for use in filling the cartridges discussed herein with the use of fewer workers than the prior art.
During the surgical procedure in which the surgical cartridges described above are used, the surgeon displaces two "sleds" longitudinally by manually depressing a trigger or otherwise actuating the surgical device that holds the cartridge. During this actuation, the sleds of the cartridge drive the drivers out of their home position, thereby driving the staples into the tissue, and a knife is displaced to make the incision. It is important that the knife make the incision either after, or while, the staples are driven into the tissue.
It is possible for too many, or for fewer than the required number of, drivers to be placed in a particular aperture during assembly of the cartridge. While the latter results in harm due to a staple not being driven at one region of the incision, the former results in a jammed instrument, thereby creating a severe danger to the patient. It is extremely difficult to determine whether too many or too few drivers are placed in a particular aperture, because of the relative size of the apertures and the drivers. There is, however, no way known to Applicants to rapidly and conveniently test a cartridge to determine if it has precisely the correct number of drivers in each aperture.
Therefore, there is a need for a machine for testing whether there are too many drivers inserted in apertures in a surgical cartridge.

Method and apparatus for testing for the presence of excess drivers in a surgical cartridge


Provided are a solid-state imaging element which can be simply manufactured and can control movement of electric charges in an accumulation region with a high degree of accuracy, and a method of manufacturing the same. A solid-state imaging element (1a) includes a substrate (11) having a first conductivity type; an accumulation region (12) having a second conductivity type and provided in the substrate (11); a read-out region (13) for receiving the transferred electric charges accumulated in the accumulation region (12); and a transfer section (14) for transferring the electric charges from the accumulation region (12) to the read-out region (13). An impurity concentration modulation region 121 having a locally high concentration of an impurity having the second conductivity type, or having a locally low concentration of an impurity having the first conductivity type is formed in a part of the accumulation region (12). An area of the impurity concentration modulation region (121) per unit distance with respect to the transfer section (14), or a density of the discretely provided impurity concentration modulation region (121) increases with decreasing distance to the transfer section (14).

The solid-state imaging element such as the CCD imaging sensor or the CMOS imaging sensor is mounted on an imaging device such as a digital video camera or a digital still camera, and is mounted on various kinds of electronic devices each having an imaging function, such as a camera cell-phone, a scanner, a copying machine, and a fax machine.
The solid-state imaging element includes a photoelectric conversion unit such as a photodiode in a substrate to generate electric charges by photoelectrically converting light inputted to the substrate. The generated electric charges are accumulated in an accumulation region in the substrate, and are subsequently transferred to a read-out region in the substrate through a transfer section. Thus, based on the charges transferred to the read-out region, one signal composing an image is generated.
Recently, it has been required to make the solid-state imaging element highly sensitive. However, when the accumulation region increases in size so that the solid-state imaging element is made highly sensitive, there is a decrease in transfer speed of the electric charges through the transfer section, which causes a problem.
This problem will be described with reference to FIG. 21. FIG. 21 is a view showing a conventional solid-state imaging element. In addition, FIG. 21 (a) is a plan view of one pixel in the solid-state imaging element, FIG. 21 (b) is a cross-sectional view showing a cross-sectional surface taken along X-X in FIG. 21 (a). Furthermore, FIG. 21 (c) is a graph showing a potential in the cross-sectional surface taken along X-X in FIG. 21 (a).
As shown in FIGS. 21 (a) and (b), a solid-state imaging element 100 includes a substrate 101, an accumulation region 102 formed in the substrate 101, for accumulating electrons generated by a photoelectric conversion, a read-out region 103 formed in the substrate 101, for receiving transferred electrons accumulated in the accumulation region 102, a transfer section 104 for transferring the electrons from the accumulation region 102 to the read-out region 103, and an insulating film 105 formed on a surface of the substrate 101. The transfer section 104 serves as a gate electrode formed on the insulating film 105 and is formed between the accumulation region 102 and the read-out region 103.
The substrate 101 has a P type (P-sub), the accumulation region 102 has an N type (N−), and the read-out region 103 has the N type (N+). In the solid-state imaging element 100, an N-type high-concentration impurity region 1021 (impurity concentration modulation region) having an N type (N) is formed by separately implanting an N-type impurity into an implantation region 106 which is provided in the accumulation region 102 and which is provided adjacent to the transfer section 104. Therefore, according to the solid-state imaging element 100 in the present example, a photodiode is composed of the substrate 101 and the accumulation region 102, and the electrons are accumulated in the accumulation region 102.
When a predetermined potential is applied to the transfer section 104 in this solid-state imaging element 100, the potential in the substrate 101 just below the transfer section 104 is lowered, and the electrons accumulated in the accumulation region 102 are transferred to the read-out region 103. At this time, when an area of the accumulation region 102 is large as descried above, some electrons are accumulated in a position far away from the transfer section 104, in the accumulation region 102. Thus, it takes a long time for the electrons to reach the transfer section 104.
When the N-type high-concentration impurity region 1021 is provided in the accumulation region 102, in the solid-state imaging element 100, the electrons are accumulated in the accumulation region 102. However, as shown in FIG. 21 (c), a potential in the N-type high-concentration impurity region 1021 is lower than that of a peripheral part due to the implantation of the N-type impurity, but the potential is flat. Therefore, movement of the electrons accumulated in the N-type high-concentration impurity region 1021 to the transfer section 104 is not particularly accelerated, and it takes a long time for the electrons to reach the transfer section 104.
Thus, in the case where the electrons accumulated in the accumulation region 102 cannot be completely transferred to the read-out region 103 within a predetermined read-out period, the electrons remain in the accumulation region 102, and these electrons are added to electrons to be generated by next photoelectric conversion, so that a residual image is generated in an obtained image, which is the problem.
Thus, for example, Patent Document 1 discloses a solid-state imaging element in which movement of the electrons to the transfer section is accelerated by inclining a potential in the accumulation region. This solid-state imaging element will be described with reference to FIG. 22. FIG. 22 is a view showing a conventional solid-state imaging element. In addition, FIG. 22 (a) is a plan view of one pixel in the solid-state imaging element, FIG. 22 (b) is a cross-sectional view showing a cross-sectional surface taken along Y-Y in FIG. 22 (a). Furthermore, FIG. 22 (c) is a graph showing a potential in the cross-sectional surface taken along Y-Y in FIG. 22 (a).
As shown in FIGS. 22 (a) and (b), a solid-state imaging element 200 includes a substrate 201, accumulation regions 2021 to 2024 which are formed in the substrate 201 and which accumulate electrons generated by a photoelectric conversion, a read-out region 203 which are formed in the substrate 201 and which receives the transferred electrons accumulated in the accumulation regions 2021 to 2024, a transfer section 204 for transferring the electrons from the accumulation region 2024 to the read-out region 203, and an insulating film 205 formed on a surface of the substrate 201. The transfer section 204 serves as a gate electrode formed on the insulating film 205 and is formed between the accumulation region 2024 and the read-out region 203.
The substrate 201 has the P type (P-sub), the accumulation regions 2021 to 2024 have the N type, and the read-out region 203 has the N type (N+). Therefore, according to the solid-state imaging element 200 in the present example, a photodiode is formed of the substrate 201 and the accumulation regions 2021 to 2024, and the electrons are accumulated in the accumulation regions 2021 to 2024. The accumulation regions 2021 to 2024 are formed by sequentially implanting the N-type impurity to implantation regions 2051 to 2054. In addition, the implantation regions 2051 to 2054 are close to the transfer section 204, respectively, and the implantation regions 2051, 2052, 2053, and 2054 are decreased in size in this order.
According to the solid-state imaging element 200, a concentration (N---) of the N-type impurity in the accumulation region 2021 provided farthest from the transfer section 204 is lowest, a concentration (N--) of the N-type impurity in the accumulation region 2022 provided second farthest is second lowest, a concentration (N-) of the N-type impurity in the accumulation region 2023 provided third farthest is third lowest, and a concentration (N) of the N-type impurity in the accumulation region 2024 provided closest to the transfer section 204 is highest. Therefore, as shown in FIG. 22 (c), the potential in the accumulation regions 2021 to 2024 can be inclined so as to decrease with the decreasing distance to the transfer section 204. Thus, it is possible to accelerate the movement of the electrons in the accumulation regions 2021 to 2024 to the transfer section 204. Therefore, even when the area of the accumulation regions 2021 to 2024 increases, the electrons accumulated in the accumulation regions 2021 to 2024 can be immediately transferred to the read-out region 203.

Solid-state imaging element and method of manufacturing the same


A temporary shield for covering a vehicle wheel in the course of applying a detailing solution to the sidewall of a vehicle tire seated on the rim of the wheel and comprising a generally disk-shaped body having a plurality of circumferentially extending markings in spaced concentric relation to one another relatively near the outer peripheral edge of the body and away from the center of the body to define circumferential lines of separation for selective removal of the circumferential portions radially outwardly of a selected marking so as to size the body to the size of the wheel. The body is of generally conical configuration and the markings are defined by circumferentially extending shoulder portions concentric to one another and to the outer peripheral portion of the wheel so that when the body is cut to size to fit a particular size of wheel the shoulder portion will fit snugly over the outer peripheral portion of the wheel.

Detailing of automobile tires is customarily accomplished by spraying or otherwise applying a solution, such as, ARMORALL.RTM. over the sidewall of the tire so as to better preserve the appearance of the sidewall and minimize any tendancy of the sidewall to crack, fade or otherwise become discolored. A particular problem associated with detailing is to completely cover the vehicle wheel so as to prevent accidental spraying of the solution onto the wheel since, unless it is quickly removed, it can be unsightly and seriously detract from the appearance of the car.
Protective shields have been devised in the past for releasably covering selected parts of a wheel or tire and for example U.S. Letters Patent No. 4,784,440 to Fair discloses a shield of generally convex configuration which is provided with a central knob for manual grasping or handling purposes and is provided with a hanger bracket to engage the flange of a wheel rim for the purpose of retaining it in place during the detailing operation. U.S. Letters Patent No. 4,792,191 shows a hand-held shield composed of a cardboard material and intended to cover a vehicle wheel during a detailing operation. U.S. Letters Patent No. 2,627,839 to Hudgins discloses a wheel mask intended for use in cleaning automobile wheels. Other patents of interest are U.S. Letters Patent Nos. 1,424,199 to Humelbau; 2,580,543 to Henderson; 3,007,401 to Kordenbrock; 3,854,448 to Kromanaker; 4,628,858 to King et al and 4,792,191 to Framer.
There continues to be a definite need for a lightweight, inexpensive protective shield or cover for vehicle wheels which can be accurately fit over the wheel in such a way as to completely shield it from accidental application of the solution applied to the sidewall in detailing and assures that the shield can be securely held in place either by the hand or by releasably securing to the wheel or tire. For manufacturing purposes it is also highly desirable that one shield can be produced and interchangeably used for different sized vehicle wheels by providing concentric markings for different sized or diameter wheels so that the shield can be easily cut to the desired size and releasably held in place over the vehicle wheel during the detailing operation.


A fluid transfer device includes a syringe barrel having a chamber, a first plunger slidably movable inside the chamber, and a second plunger slidably movable inside the chamber. The distal end portion of the first plunger is engageable with the proximal end portion of the second plunger such that when the distal end portion of the first plunger and the proximal end portion of the second plunger are engaged, the second plunger is movable by the first plunger. A check valve may be incorporated into the distal end portion of the second plunger to allow a fluid to pass therethrough in a direction towards the proximal end portion of the second plunger and prevent a fluid to pass therethrough in a reverse direction. A fluid transfer assembly and a sampling method are also described.

In pharmaceutical, biotechnology, food, beverage, and other industries, it is often desired to take many samples to monitor process development and/or optimize process steps. Conventional fluid sampling is commonly conducted with a needle-free sampling valve connected to a reactor or other processing vessels via small diameter tubing. The operator first swabs the connection of the sampling valve with a cleaner, typically an ethanol or methanol solution. Next a standard syringe is connected and a full sample is drawn, disconnected, and discarded. This is done to clear the tubing and valve of any dead leg which would result in an inaccurate reading. Then, the sampling valve is cleaned again and a new syringe is connected to take a representative sample.
The conventional process of cleaning is operator-dependant and can easily be missed or improperly conducted. Further, to get a sample, the operator needs to connect twice to the system with different sampling devices, doubling the chance of contamination. Therefore, there is a need for an improved fluid transfer device, system, and method that can overcome the various disadvantages in conventional fluid sampling.

Fluid transfer device, system and method


A screw and driver combination designed so that the screw is releasably axially couplable with the driver and so that the screw is positively rotatably engageable with the driver. The screw comprises an axial bore of circular cross section and a counterbore of polygonal cross section. The driver comprises a radially-compressible front portion sized to engage the axial bore of the screw with a minor spring interference fit and an intermediate portion sized to positively rotatably engage the counterbore of the screw.

In certain situations, it is desirable that a screw be both rotationally as well as axially releasably couplable with a driver. For instance, in limited-access work applications, e.g., in arthroscopic or other "closed" surgeries, where a screw is to be inserted into a hole which is not readily accessible, it is advantageous to axially couple the screw with the driver before inserting the screw into the surgical site. Such axial coupling is also beneficial where the screw implantation site is accessible, e.g. where the screw is inserted in a downwardly facing hole.
With such screw and driver combinations, the screw is first attached to the driver and then the driver is manipulated until the screw contacts the implantation site, whereupon the driver is rotated until the screw is fully implanted. Then, the driver is disengaged from the screw by pulling it axially away from the screw.
Such screw and driver combinations are known in the art, as illustrated by U.S. Pat. Nos. 2,329,398, 2,511,051, 2,775,913, 3,463,209, 3,695,321, and 3,888,144. Known screw and driver combinations typically suffer from one or more problems which limit their utility and acceptance in certain situations. For instance, known screw and driver assemblies when designed to provide sufficient axially locking engagement can be difficult to operate, inasmuch as the driver must be inserted with an unacceptably large axial force to overcome the frictional interference between screw and driver. With some screw and driver combinations, the rotational engagement between the screw and driver is not sufficiently positive, i.e., there often is an unacceptably large amount of play between the screw and driver. Other screw and driver combinations (1) tend to be relatively expensive to produce due to the relatively complex shapes of the screw and driver and (2) can permit some axial wobble between screw and driver, i.e., the combination is not designed to ensure the driver is always perfectly co-axially aligned with the screw.

Screw and driver for securing a bone block


An element of an office panel includes a back support member closed at either end by molded end pieces. The molded end pieces in combination with the back support member define a front opening recess into which a filler material is inserted. A decorative facing material is applied over the filler material and attached to the back support member and the molded end pieces, whereby the facing material forms a finish face of the element. With this arrangement, the back support member is more easily manufactured, as it is open at either end and the molded end pieces can easily be inserted within the back support member to effectively close the member and provide a complete support for the element. According to an aspect of the invention, the molded end pieces include molded components thereon by means of which the element can be effectively supported by an office panel frame.

Office panelling systems for subdividing office space have become a well recognized approach for effectively subdividing office space and defining various work stations. One of the most popular approaches with respect to office panelling systems is that each office panel has a separate frame to which office panel elements are secured to effectively cover the frame and provide a finished surface. Each frame may be adapted to receive a plurality of office panel elements to one side or to both sides and typically the frames have a plurality of vertical members interconnected by horizontal members or horizontal rail members.
These office panel elements are designed to absorb sound and have a sound absorbing filler material immediately behind the facing material which is often cloth, particularly in the case of sound absorbing elements. A metal back support member provides the recess for receiving and supporting the filler material and has typically been made of a metal, having metal sides and metal ends with the front being open for receiving the filler material. The fabric is then applied over the combination and is typically adhesively secured in a more or less tensioned state to the rear surface of the back support. Each element typically includes a peripheral edge region of shallower depth which overlaps with the frame, with a central area being of greater depth and being received within the recess of the frame. Various clips are secured to the back support and often form a spring detente arrangement maintaining the element within an office panel frame. As can be appreciated, the procedures for manufacturing of the back support require closing of both the sides and ends and complicate the manufacture of the element.


A detector detects whether or not a first line induced voltage and a second line induced voltage match each other, the first line induced voltage being a potential difference of a first phase potential of phase potentials relative to a reference potential, and the second line induced voltage being a potential difference of a second phase potential of the phase potentials other than the first phase potential relative to the reference potential. The phase potentials is outputted by the armature due to an induced electromotive force. The reference potential is any one of a minimum phase and a maximum phase. A rotation-position setting unit sets, to a predetermined value, an estimation value of a rotation position of the motor 2 at a point in time when the first line induced voltage and the second line induced voltage match each other.

In Japanese Patent Application Laid-Open No. 2010-233390 an inverter that drives a permanent-magnet synchronous motor is described, and a rotation position of the motor is detected based on a line voltage of the motor. In Japanese Patent Application Laid-Open No. 2010-233390, phase voltages are detected, and a line voltage is calculated based on these phase voltages. Then, by detecting a zero-crossing point of these line voltages, a rotation position of the motor is determined to a position corresponding to the zero-crossing point.
Further, as techniques relevant to the present disclosure, Japanese Patent Application Laid-Open No. 2011-19348 and Japanese Patent No. 2609840 are disclosed.

Device for detecting rotation position and air conditioner


The present invention provides apparatus for utilizing planar HTS probe coils in substantially coplanar coil sets, each set comprised of a plurality of coils, two such similar sets being positioned on opposite sides of the sample to form a plurality of coil pairs. The coil pairs may be used for excitation of the sample, for receiving the NMR response signal or for both. A feature of the invention is the ability afforded to adjust the coupling between coil pairs to a minimum value to thereby prevent interaction between coil pairs having simultaneously applied high power signals and weak NMR response signals.

Nuclear magnetic resonance (NMR) spectrometers first became available in 1946. In 1950 observations of "shifted" resonances in nitrogen spectra by W. G. Proctor & F. C. Yu, Phys. Rev. 77, 717, (1950) stimulated efforts to improve the homogeneity and stability of magnets used in the experiments and led to the observation of chemically shifted resonances in proton spectra by J. T. Arnold, S. S. Dharmatti, and M. E. Packard, Jour. Chem. Phys. 19, 1608, (1951). This marked the beginning of high resolution NMR and its application as an analytical tool for chemistry, and sparked rapid growth in the development of NMR spectrometers. This development continues today at a pace limited only by the availability of relevant technology. Recent work is predicated upon improvements in rf probe performance incorporating receiver coils made from recently available high temperature superconducting (HTS) materials.
Nuclei of most isotopes of the elements have non-zero spin and exhibit gyromagnetic properties. They behave like microscopic spinning bar magnets and possess a coupled nuclear magnetic moment. In the absence of an externally applied magnetic field the nuclear moments of an ensemble of non-zero spin nuclei are randomly oriented in their atomic or molecular environment. When a static homogeneous magnetic field B is applied, the magnetic moments interact with the field and become oriented with respect to it. The spins are then said to be "polarized" by the field. Only certain orientations are allowed in accordance with well known quantum mechanical principles as described in "Nuclear Magnetic Resonance--Principles and Theory", R Kitamaru, eds. Elsevier Science Publishers, 1990, Chap 2, pp. 25-36. As a consequence of the interaction of the field with the nuclear spin system, the nuclear energy level splits into multiple discrete levels corresponding to the different allowed orientations. Nuclei with spin equal 1/2 are the most suitable and most frequently used for high resolution NMR experiments. For simplicity and without loss of generality with respect to this present work, spin equal 1/2 nuclei will be assumed hereinafter. The split into two energy levels, corresponds to magnetic quantum numbers +1/2 and -1/2 for a spin 1/2 nucleus. The separation of the energy levels is proportional to the intensity of the magnetic field at the nucleus and to a proportionality constant .gamma. called the magnetogyric ratio. In thermal equilibrium in the static field, a Boltzmann distribution of energies is maintained. There are more spins in the lower energy state than in the higher energy state. This difference is called the Boltzmann excess.
When an ensemble of nuclei are simultaneously subjected to both a static magnetic field and an appropriate rf magnetic field of frequency .nu. such that the energy of a quantum of radiation h.nu., where h is Planck's constant, is equal to the energy difference between the two spin energy levels, transitions can occur with equal probability from one state to the other. Due to the Boltzmann excess there is a net absorption of energy by the nucleus from the rf field. This transfer of energy is a necessary condition for obtaining a NMR signal.
In the aggregate, large ensembles of nuclei such as would be present in practical size samples obey the laws of classical dynamics. For convenience of visualization and ease of understanding, a classical vector model of the NMR phenomenon is hereinafter described.
With the static magnetic field applied, individual nuclei align themselves to the field, some with their microscopic magnetization vector substantially in the direction of the field, which is the low energy state corresponding to spin equal +1/2. Also, some nuclei align with their magnetization vector substantially in the direction opposite to the field, which is the high energy state corresponding to spin equal -1/2. In accordance with the Larmour Precession Theorem the individual nuclei precess about the direction of the field with an angular frequency .omega..sub.L =.gamma.B, where .gamma. is the aforementioned magnetogyric ratio for each of the isotopic species, and B is the local field at the nuclei. More nuclei align in the direction of the field than in the direction opposite to the field, the difference being equal to the Boltzmann excess. Therefore, collectively the ensemble of nuclei exhibits a net macroscopic nuclear magnetization vector in the direction of the applied polarizing field B.
To generate a NMR signal, rf excitation is applied to the sample by a rotating magnetic field in the plane perpendicular to the direction of the polarizing field thereby enabling a transfer of energy to the spin system. The rotating field is provided by an alternating current in an excitation coil having its axis of symmetry perpendicular to the direction of the polarizing field. A linear oscillating magnetic field is generated along the x- axis of the excitation coil as shown in FIG. 1a. The linear oscillating field can be decomposed into two counterrotating components, one of which, usually called the B.sub.1 field, rotates in the direction of rotation of the aforementioned ensemble of nuclear spins, as shown in FIG. 1b. When the angular frequency .omega. of the two rotating magnetic field components 20 and 22 is equal to .omega..sub.L, the angular frequency of precession of the ensemble of nuclei 23, a resonance condition exists and, as shown in FIG. 1c, the net magnetization vector 8 tilts away from the z-axis 24 which is the direction of the static polarizing field 12 and precesses about it. As the magnetization vector 8 precesses about the polarizing field, it intersects the turns of a receiver coil, thereby generating a NMR signal. At resonance the angular frequency .omega. in the vector description equals 2.pi..nu., where .nu. is the frequency of excitation which produces transitions between spin states in the quantum description of the phenomenon.
The broad general utility of NMR as a tool for determining the chemical structure of compounds is due to the influence of the molecular environment on the local magnetic field at the nuclei. The local magnetic field at the nucleus of a particular nuclear species at a particular site in a molecule is the vector addition of the externally applied field, altered slightly by the magnetic influence of its molecular environment. By way of example, circulation of electrons about the nucleus caused by the applied field results in an induced field at the nucleus which in some instances opposes the applied field (diamagnetism), and in some instances augments it (paramagnetism). By way of further example the local field at the nucleus can be additionally modified, taking on multiple values or "splitting" due to interactions with other non-zero spin nuclei in the molecule. As discussed hereinafter, these two effects, known as "chemical shift" and "spin-spin coupling" respectively are major sources of the fine structure seen in NMR spectra as described in "Introduction To NMR Spectroscopy", R. Abrahms.; J Fisher, P. Loftus, pubs. J Wiley & Sons, 1993, chap. 2, pp. 13-33, chap. 3, pp. 34-53. NMR spectra which are characterized by resonance lines that are narrower than the shifts in resonance caused by chemical shift and spin-spin coupling are known as high resolution spectra and are primarily made possible by the application of an extremely homogeneous polarizing field.
An NMR spectrometer is comprised of: 1) a D.C. magnet which provides said stable homogeneous magnetic field for polarizing the spins, 2) an rf system which provides a suitable rf excitation signal, 3) a coil or a plurality of coils for coupling the rf excitation to the spins and for receiving the NMR response signal, 4) a detection system for detecting the NMR response signal, 5) a signal processing system for processing the detected NMR response signal, and 6) an output device for displaying the NMR signal. For high resolution NMR studies, the compound under investigation is usually dissolved in or mixed with a suitable solvent and is in liquid form contained in a sample tube which is typically 5 mm in diameter. The sample is held in a sample holder portion of a probe which positions it in the most homogeneous region in the magnetic field. The coil or coils for coupling the rf excitation to the sample and for detecting the NMR signal are mounted on the probe.
NMR is an inherently insensitive technique. Sensitivity is strictly defined in terms of the minimum concentration of a test material required to produce a signal that is just detectable above the level of noise. For practical purposes however, the signal to noise ratio, S/N, is generally considered a good measure of sensitivity and the terms sensitivity and S/N ratio will be used interchangeably hereinafter.
The NMR signal is small for two fundamental reasons and numerous practical considerations. The first fundamental reason is that the energy changes involved in NMR transitions are small, and the second is that the net absorption of energy by an ensemble of nuclei is proportional to only the excess in population of the lower of the two energy states involved in the transition (i.e. the Boltzmann excess), rather than the total population. Specifically, the ratio of the number of spins in the higher energy state to the number in the lower energy state is (1-h.nu./kT) where k is the Boltzmann constant. Therefore this excess population is very small, a typical value being of the order of 1 part in 10.sup.5. Other reasons for the small signal include the need to use dilute solutions of the species being observed, either because of limited availability of sample material or to prevent spectra being complicated and rendered unreproducible by the effects of intermolecular coupling.
As further discussed hereinafter, the dominant source of noise which enters into the determination of sensitivity is generally thermal noise originating in the receiver coil of the spectrometer.
In early continuous wave (CW) spectrometers, sample resonances were excited one at a time by a continuous sweep of the rf excitation or static magnetic field.
In modern NMR spectrometers one or more high intensity rf excitation pulses of short duration are applied and the NMR response of the spin system to the excitation is received and recorded as the spin system relaxes back towards its equilibrium state. The receiver is off during the excitation pulse. Then when the transmitter is switched off, the receiver is switched on to record the NMR response. Since one is off when the other is on, the excitation and receive functions can time share the same coil. Alternately, separate coils can be used for excitation and reception. When the rf excitation is removed the magnetization vector relaxes and precesses about the static field. As it precesses and intersects the turns of the receiver coil, an NMR time domain response signal called a Free Induction Decay, FID, is generated. The terminology "Free Induction Decay" derives from the characterization of the signal as being induced by a magnetization vector "free" of the influence of the rf excitation, while it is "decaying" back to equilibrium. The time domain FID signal is then converted to a frequency domain spectrum, by means of a Fourier Transformation. Instruments operating in this manner are called Pulsed FT NMR Spectrometers.
In a pulsed FT spectrometer all frequencies in the spectral band of interest are excited simultaneously and the resulting FID, when Fourier transformed, yields a spectrum over the entire band of interest. The time for acquiring data in a pulsed spectrometer is therefore greatly reduced and as a consequence, time averaging of FID's from multiple scans can be done in a reasonable time prior to Fourier transformation of the data. This results in an improvement in the signal to noise ratio, S/N, on the order of the square root of the number of scans. Time averaging is one of many methods and techniques that are routinely used to improve the sensitivity of NMR spectrometers.
Continued improvement in sensitivity has been a constant objective in the development of NMR spectrometers. Increasing signal strength, reducing noise, and improving signal processing methods have all contributed. Many of the factors that influence the attainable signal to noise ratio are treated in "A Handbook of Nuclear Magnetic Resonance ", R. Freeman, pubs, Longman Scientific & Technical, 1988, pp. 216-229 which is hereby incorporated herein by reference. As discussed hereinafter, the signal to noise ratio can be further improved by cooling the receiver coil to a very low temperature while maintaining the sample at or near room temperature to reduce Johnson noise.
The available signal is proportional to both the nuclear magnetization and to the resonance frequency. Since the nuclear magnetization is proportional to the resonance frequency, the available signal for a given species is proportional to the square of the resonance frequency. Noise considerations however reduce the dependence of sensitivity on the resonance frequency to .omega..sup.3/2 Largely because of this strong dependence of sensitivity on frequency, the trend has been toward higher and higher magnetic field strength and correspondingly higher values of NMR frequencies. Most modern NMR spectrometers utilize superconducting magnets capable of providing fields as intense as 18 tesla which are homogeneous over suitable sample size volumes. 17.6 tesla corresponds to an NMR frequency of 750 Mhz for protons.
Most modern NMR spectrometers have three separate transmitter channels: one to provide for a conventional field-frequency lock system, a second to provide the signal for observing the nucleus under study, and a third to provide 2D and decoupling capability. A block diagram of a typical modern pulsed spectrometer is shown in FIG. 2.
The probe is a critical component in an NMR spectrometer. For a given static magnetic field strength and a given sample size, the performance of the probe defines the sensitivity of the spectrometer. An important consideration in probe design is the coupling efficiency .zeta. of the receiver coil to the sample. .zeta. is the ratio of effective inductance to total inductance of the receiver coil. Any portion of the inductance of the receiver coil that does not contribute towards the detection of the NMR signal, such as coil leads by way of example, results in a loss of sensitivity proportional to .zeta..sup.1/2. Another important consideration is the quality factor Q of the receiver coil which affects sensitivity by a factor of Q.sup.1/2 since signal voltage is proportional to Q and noise voltage is proportional to Q.sup.1/2. Q represents the ratio of energy stored in the receiver coil resonant circuit to the energy dissipated through resistive losses in the circuit. Another important consideration in probe design is the receiver-coil filling factor .xi. which, for a fixed coil- volume, influences the signal strength and the sensitivity directly. In the simple case of a cylindrical coil with diameter d.sub.c wrapped around a cylindrical sample with diameter d.sub.s, .xi. would be approximately (d.sub.s /d.sub.c).sup.2. .xi. is a measure of the energy stored in the transverse magnetic field coupling to the sample, compared to the total magnetic energy stored in the receiver coil resonant circuit. Filling factor .xi., coupling efficiency .zeta., and quality factor Q should all be as large as possible for maximum sensitivity.
In many cases it is desirable, to simultaneously irradiate an NMR sample with several rf fields, each with a different frequency, without strong interaction occurring between the circuits producing the irradiating fields and the circuits detecting the responses. It is known in the art that transmitter drive can be largely decoupled from receiver coils by positioning the transmitter and the receiver coils on the probe at right angles to each other. This so called quadrature-coil configuration minimizes flux coupling between the coils. By making the mutual inductance between the coils very small the coupling of the strong irradiating signal to the sensitive receiver circuit can be largely eliminated.
Modern spectrometers use superconducting magnets. The cylindrical sample is positioned coaxially with the D.C. magnet. The transmitter and receiver coils can be a saddle coil as shown in FIG. 3a or a split formed-wire coil as shown in FIG. 3b. Either are ordinarily shaped to couple closely to the sample while providing the required B.sub.1 field orthogonal to the static field B. Using high temperature superconducting (ITS) materials, coils have been fabricated by depositing a thin layer of superconductor on a flat dielectric substrate 45. A pair of such coils forming a magnetically coupled system, a Helmholtz pair, are shown in FIG. 4a, placed on opposite sides of a sample is in the prior art. Also in the prior art, a second pair of similar HTS coils is shown positioned orthogonal to the first pair as shown in FIG. 4b to simultaneously provide a field-frequency lock signal. HTS coils can have high currents induced therein which can drive the coil normal and destroy the Q or significantly reduce the Q resulting in loss of detection sensitivity.
Best results are obtained with HTS coils when the superconductor is lattice matched to the substrate, i.e. grown epitaxially. The substrate 45 should be a thermally conductive material to facilitate cooling of the coil and should have low magnetic susceptibility to avoid degrading the homogeneity of the magnetic field. Acceptable substrate materials include sapphire, lanthanum aluminate, and magnesium oxide. A preferred HTS material is YBa.sub.2 Cu.sub.3 O.sub.7-.delta. (YBCO), which has a critical transition temperature T.sub.c of approximately 87.degree. K. A coil made of this material is described in "HTS Receiver Coils For Magnetic Resonance Instruments", R. S. Withers, B. F. Cole, M E. Johansson, G. C. Liang, G. Zaharchuk, Proc. SPIE, 2156, 27-35, (1994).
For proper performance HTS coils must be maintained at a temperature significantly below their transition temperature T.sub.c. Joule-Thomson and Gifford-McMahon closed cycle refrigerators are known which cool the coils to 25.degree. K. The coils are thermally isolated from the samples in this equipment and the samples can be maintained at or near room temperature if desired.
High resolution NMR probes using HTS coils can provide higher sensitivity than probes with non-superconducting coils. For a given sample volume the sensitivity of a coil is proportional to (.xi.Q/T).sup.1/2 where T is the coil temperature and .xi. and Q are the aforementioned filling factor and quality factor respectively. A superconducting coil may have a Q of 20,000 compared with 250 for a room temperature coil and can operate at 25.degree. K. With the geometry appropriate for a 5 mm. sample tube, and allowing for the loss of filling factor required for thermal isolation of the sample from the coil, the potential sensitivity gain can approach a factor of 10.
Any of the aforementioned coil configurations can be used to provide excitation and to detect NMR responses at more than one frequency by tuning the probe coil circuit to resonate at more than one frequency. However, since inductive elements are used to provide the frequency separation, multiple tuning degrades performance of the probe compared to a single tuned probe because of the inevitable reduction in the aforementioned coupling coefficient .zeta.. Combining the use of multiple tuning of probe coil circuits and orthogonal coil disposition, any of the aforementioned prior art probe arrangements can provide rf excitation and reception of NMR responses at several different frequencies. Disadvantages of the prior art probe when used in this way include the aforementioned reduction in sensitivity due to lower coupling coefficient as well as high cost of fabrication. Additionally it is difficult to perform adjustments to minimize mutual coupling between orthogonal pairs.

Coplanar RF probe coil arrangement for multifrequency excitation


A MOSFET device utilizes the gate depletion effect to reduce the oxide field over the junction area. Since the gate depletion effect is present in the non-conducting off state for n.sup.+ gate PMOS devices and p.sup.+ gate NMOS devices, performance degradation is overcome. The level of doping of the gate is critical. In order to prevent gate depletion in the conducting, on state, the NMOS FET must use a highly doped n.sup.+ gate. The PMOS FET n.sup.+ gate must be non-degeneratively doped in order to utilize the advantage of the gate depletion in the non-conducting, off state. This is accomplished by implanting different doses of the same dopant type into the different gates. The MOSFET device can be implemented equally well for n.sup.+ gate PMOS FET devices as well as for p.sup.+ gate NMOS FET devices.

A typical CMOS circuit application can provide very low standby power. Current flows in the circuit only when a transition of state is occurring. This feature makes it extremely easy to manage the power dissipation in CMOS designs. For an n-channel MOS device the current carriers are electrons, whereas for a p-channel MOS device the carriers are holes. Four separate regions or terminals exist in a MOS transistor: source, drain, gate, and substrate. For normal operation, the source, drain, and gate voltages measured with respect to substrate are positive for an n-channel device and negative for a p-channel device. The output is always connected to one of the power supply rails because at any given state only one transistor is on and the other is off. This guarantees that the logic swing will be determined by the power supply voltage only, and not by the ratio of the effective impedance of the devices, as is the case with static nMOS design.
In semiconductor technology, polycrystalline silicon (polysilicon) is very frequently used as a gate electrode. The popularity of polysilicon is largely due to the fact that polysilicon is a particularly suitable material in self-registering MOS processes, in which the gate electrode and source/drain areas are defined by the same masking step. In integrated circuits, polysilicon is used for circuit wiring as well as a gate electrode.
In the realization of submicron MOSFETs decreasing gate oxide thickness (T.sub.OX), the correspondingly increasing electric field across the thin dielectric is a major concern. With gate oxide thickness of 10 nm and smaller, the supply voltage had to be reduced from 5 V to 3.3 V in order to reduce the electric field across the dielectric to a safe level of below 4 MV/cm. However, with decreasing supply voltage, the field enhancement caused by the workfunction difference between the n.sup.+ gates and p.sup.+ junctions, or the p.sup.+ gates and n.sup.+ junctions, becomes increasingly important. The workfunction difference of 1.1 eV remains constant with decreasing supply voltage. The oxide field (E.sub.OX) can be calculated by utilizing the formula shown in Equation 1 where V.sub.gate represents the gate voltage, V.sub.fb represents the flatband voltage, and T.sub.OX represents the oxide thickness. EQU E.sub.OX =[(.+-.V.sub.gate)+(.+-.V.sub.fb)]/T.sub.OX
Equation 1.
The flatband voltage (V.sub.fb) can be calculated by utilizing the formula shown in Equation 2 where .phi..sub.ms represents the workfunction difference, Q.sub.ox represents the oxide charge and C.sub.ox the oxide capacitance. EQU V.sub.fb =.phi..sub.ms +Q.sub.ox /C.sub.ox
Equation 2.
Depending upon the bias of the gate and source, the workfunction difference (.phi..sub.ms) will increase or decrease the electric field in the gate/junction region as evident from Equation 1. FIG. 1 illustrates the gate-to-junction area of a MOSFET 10, having an n.sup.+ gate 12, n.sup.- substrate 14 and p.sup.+ junction 16 with a gate oxide thickness (T.sub.OX) 18. The oxide field 20 is affected by the workfunction difference (.phi..sub.ms) according to Equation 1.
Referring to FIG. 2, there is shown, the effect of the gate polarity on oxide field between source and drain of n.sup.+ PMOS devices and p.sup.+ PMOS devices which are in a conducting state, turned on. FIG. 3. shows the simulated oxide field along the channel for n.sup.+ PMOS and p.sup.+ PMOS devices which are in a non-conducting state, turned off. The field enhancement of approximately 1 MV/cm for n.sup.+ PMOS FETs is due to the added workfunction difference. The results shown in FIGS. 2 and 3 were obtained with two dimensional computer simulations utilizing MINIMOS. In the non-conducting off state the oxide field is increased by the workfunction difference up to 4.6 MV/cm at the drain side for the n.sup.+ gate PMOS when a nominal oxide thickness of 10 nm is assumed. When a process variation of 10% in T.sub.OX is accounted for, a maximum oxide field of 5 MV/cm will result. This enhanced oxide field will increase the risk of device failures such as oxide breakdowns and device instabilities.
MOSFETs having equal gate and junction dopant type, i.e. p.sup.+ gate PMOS and n.sup.+ gate NMOS, have been proposed in order to avoid the high oxide fields which were described above. Referring to FIGS. 2 and 3, it can be seen that the oxide field of the p.sup.+ gate PMOS device remains below 3.6 MV/cm. However, the actual implementation of such a symmetrical device design in CMOS technology complicates the process substantially. This is because a dual workfunction gate technology is required. Information on the feasibility of fabricating dual gate CMOS devices can be obtained by referring to an article entitled "Doping of n+ and p+ Polysilicon in a Dual-Gate CMOS Process" by C. Y. Wong et al published by IEEE in IEDM Tech. Dig. 238 (1988). A polysilicon depletion occurs at reverse biases, which causes device current degradation. This effect becomes more severe as the gate oxide thickness (T.sub.OX) becomes smaller. Reference is made to an article entitled "Effects of Depleted Poly-Si Gate on MOSFET Performance" by M. Iwase et al published in Ext. Abstract SSDM 271 (1990) for information on dual gate symmetric CMOS structures for sub-micron integration and degradation of performance by the depleted gate on the device.
Therefore, reducing the workfunction related high oxide fields for single workfunction gate technologies, such as for n.sup.+ gate only and p.sup.+ gate only, for CMOS is highly desirable. One solution is through the controlled formation of gate birds beaks which have the tendency to increase the oxide thickness at the gate edges. This solution, however leads to a transconductance degradation which results in a loss of performance.
It is an object of the present invention to reduce the oxide field over the junction area.

Off-state gate-oxide field reduction in CMOS


A probe is provided for measuring the wear of a wall in a metallurgical vessel. The probe includes at least two electrically conducting elements which extend generally mutually parallel, and a tubular sheath wherein the electrically conducting elements extend interiorly of said sheath, and are mutually insulated via a refractory insulator. The probe is adapted to be implanted in the transverse direction in the wall of a metallurgical vessel with the distal end of each of the two electrically conducting elements being disposed at the interior surface of said wall. A measurement system is connected to the opposite proximal ends of the electrically conducting elements for measuring an electrical characteristic of the circuit formed by said elements that depends on the length of the elements. The probe has a diameter less than 1 mm achieved by stretching after the components have been assembled into an intermediate assembly having a larger cross sectional area than the final cross section.

The invention relates generally to measurement of the wear of a wall of a metallurgical vessel. The word "wall" as used here refers to any body comprised of refractory material which is susceptible to be progressively consumed when in contact with fused metal contained in the vessel. The invention may thus be employed for continuously measuring: the wear of a refractory lining, or the wear of organs implanted in a refractory lining (e.g. tuyeres for oxygen injection in a converter), or the wear of elements for injecting agitation gas, or the wear of bottom electrodes in an electric arc furnace.
Consider the example of tuyeres disposed in the lining of a converter, which tuyeres traverse the wall of the converter and serve for injection of a treatment fluid, which may be a gas (e.g. oxygen) or a liquid, into the fused metal, which metal contacts the tuyeres during the treatment. It turns out that the erosion of the refractory material is particularly high in the neighborhood of the zones of injection of the gas (or liquid) into the vessel, which injection occurs at the outlets of the tuyeres. One reason why it is particularly desirable to be able to monitor, as accurately as possible, the advance of such erosion, is that such knowledge enables one to take into account the influence of the erosion pattern itself on the parameters of the injection of the fluid. Another reason is that erosion of the refractory material of and near the tuyeres is difficult to predict, and thus monitoring is important in order to avoid the risk of failure of the lining and the vessel wall or tuyere structure.
Accordingly, there have long been efforts to provide means of measuring the wear of refractory materials by measuring the variation in the thickness of the wall formed by or with said materials.
One early technique consists of implanting in the refractory material of the lining, or of the tuyeres, a plurality of thermocouples at various depths in the direction of propagation of the wear, i.e., generally at various depths in the direction of the thickness of the refractory material. This technique has been used, e.g., for tuyeres comprised of permeable refractory elements of the type known as "LBE," as described in Fr. Pat. 2,518,240. The advance of the erosion is monitored via the signals from the different thermocouples implanted in a given permeable element, wherewith a sharp change in the signal indicates that the metal has arrived in contact with a given thermocouple junction in consequence of erosion of the refractory material surrounding said junction. This method of monitoring wear is necessarily discrete or stepwise, in that a new wear signal does not appear until the wear of the refractory advances by a distance through the thickness thereof which distance equals the separation of two thermocouples in the thickness direction.
More recently, instrument makers have proposed apparatuses which aim to achieve continuous measurement by continuously measuring the electrical resistance of a resistive wire disposed in the refractory material, which wire extends in the direction of the thickness of said refractory material. As the refractory material is eroded, the length of the resistive wire is reduced, along with its electrical resistance. Thus, measuring the resistance enables one to monitor the change in thickness of the refractory material resulting from erosion of the refractory material. In practice, the device employed for continuously measuring the length of an injection tuyere, such as described in Fr. Pat. 2,728,336, is a probe comprised of two electrical conductors extending parallelly and separated by an electrically insulating refractory material. The two conductors are connected to means of measuring electrical resistance capable of measuring the variations in resistance resulting from variations in the length of the conductors as the refractory lining of the metallurgical vessel is eroded, wherewith closure of the circuit is provided by the fused metal itself contained in said vessel. At least one of the two conductors is comprised of a material having sufficient resistivity to enable practicable and accurate measurement. Such probes are used principally for measuring wear at fluid-injection tuyeres, in that, in practice, it is necessary to have substantial movement of fused metal such as occurs near the end of the tuyere in order to disturb the deposit of electrically insulating dross present on the wall, and thereby to ensure good electrical connection between the ends of the two conductors.
According to a preferred embodiment described in the above-cited Fr. Pat. 2,728,336, the probe is in the form of a coaxial cable having a central conductor surrounded by an insulating sleeve comprised of an electrically insulating refractory material, e.g., alumina, which sleeve is in turn surrounded by a metal sheath comprised of, e.g., steel or Inconel.RTM., which sheath serves as the second conductor and provides a strong structure for the probe. The central conductor, comprised of, e.g., a steel-based material or a material based on molybdenum bi-silicide, has a resistance per unit length on the order of, e.g., 45 ohm/m, which is appreciably greater than that of the metal sheath.
The method of fabrication according to the state of the art leads to a probe having an external diameter of c. 1.5 mm; the insulating sleeve comprised of alumina, consisting of tubular elements disposed interiorly of the metal sheath, is quite thick, having a thickness on the order of several tenths of a millimeter. Such probes have low flexibility and are ill suited for implantation into difficultly accessible locations, e.g. tuyeres of converters. Moreover, the distance between the central conductor and the exterior metal sheath is such that there is no assurance that a good electrical link will be provided between them via the fused metal contained in the vessel. Defects in this electrical link result in errors in the measurement of the resistance, and thereby of the erosion, in that fluctuations in the resistance measured do not correspond to changes in the length of the central conductor.
It may even be impossible to employ such a probe where one desires to measure the erosion of a refractory material in a region of the vessel having a continuous refractory lining, because the insulating layer of dross covering the surface of the refractory bricks quasi-permanently interferes with electrical linkage of the two conductors in the probe.

Apparatus and method of continuously measuring the wear of a wall of a metallurgical vessel


A drum unit is provided, which includes a frame configured such that a development cartridge including a pressed portion is detachably attached thereto, and a pressing member. The development cartridge is movable between a pressed state where the pressed portion is pressed by the pressing member when attached to the frame and a released state where the pressed portion is released from pressing of the pressing member when the development cartridge is attached to the frame. The pressing member includes a pressing section that contacts and presses the pressed portion when the development cartridge is in the pressed state, and a restriction section configured to, when the development cartridge is in the pressing state, restrict movement of the pressed portion in a released direction, in which the pressed portion moves when the development cartridge moves from the pressing state to the released state.

1. Technical Field
The following description relates to one or more process units, each of which includes a drum unit and a development cartridge, for an image forming apparatus such as a laser printer.
2. Related Art
In an example of an image forming apparatus such as a laser printer, a drum cartridge holding a photoconductive drum is detachably attached into a main body of the apparatus. Further, the drum cartridge includes a development cartridge attached thereto that supports a development roller. The drum cartridge having the development cartridge attached thereto constitutes a process cartridge.
In a state where the development cartridge is attached to the drum cartridge, the development roller contacts the photoconductive drum. In order to make the development roller contact the photoconductive drum under a predetermined pressing force, the drum cartridge includes a pressing member by which the development cartridge is pressed against the photoconductive drum. Specifically, the pressing member is urged by a compression spring. The development cartridge includes a development-side boss. When the development cartridge is attached to the drum cartridge, the pressing member contacts the development-side boss, and the pressing member is pressed against the development-side boss by an urging force of the compression spring so as to establish a pressure-contact between the development roller and the photoconductive drum.

Drum unit, development cartridge detachably attachable to the drum unit, and image forming apparatus having the drum unit and the development cartridge


A temperature controlled case includes a housing that defines a temperature controlled space and a multi-circuit cooling element in thermal communication with the temperature controlled space. The multi-circuit cooling element includes two or more cooling coils. Each of the cooling coils is coupled to a different circuit structured to selectively circulate coolant through the multi-circuit cooling element. Each circuit is fluidly separate from each remaining circuit such that the coolant circulated through each circuit is not shared with each remaining circuit. The multi-circuit cooling element further includes a plurality of heat exchange fins coupled to each of the two or more cooling coils such that each of the heat exchange fins facilitates heat removal from the temperature controlled space by each of the two or more cooling coils.

Temperature controlled cases are used for the storage, preservation, and presentation of products, such as food products including perishable meat, dairy, seafood, produce, etc. These cases (e.g., refrigerated cases, freezers, merchandisers, etc.) are typically provided in both commercial (e.g., supermarkets, etc.) and residential settings. To facilitate the preservation of the products, temperature controlled cases often include one or more cooling systems for maintaining a display area of the case at a desired temperature.
The cooling systems may include one or more cooling elements (e.g., cooling coils, heat exchangers, evaporators, fan-coil units, etc.) through which a coolant is circulated (e.g., a liquid such as a glycol-water mixture, a refrigerant, etc.) to provide cooling to an internal cavity of the case. As a result of the cooling, the food products are typically maintained in a chilled state, which reduces a likelihood of spoilage for future retrieval and consumption.

Multi-circuit cooling element for a refrigeration system


An anti ice skidding apparatus for providing resistance to lateral forces acting on a vehicle. The anti ice skidding apparatus includes a disc chassis, a device for engaging a roadway pivotally connected to the disc chassis and a device for securing the disc chassis to an underside of the vehicle. A device is connected to the securing device for pivoting the securing device between a first position maintaining the disc chassis and engaging device at a distance above the roadway and a second position placing the engaging device in engagement with the roadway. The engaging device is able to engage the roadway and provide additional resistance to lateral forces acting on the vehicle when in the second position. The engaging device may be one of a plurality of rollers or a blade which will engage with icy surfaces on the roadway and cut a groove in the icy surface to provide additional resistance to the lateral forces acting on the vehicle. The plurality of rollers and the blade each include a sharp edge extending around a periphery thereof, the sharp edge acting to cut a groove on any icy or soft surfaces over which the vehicle passes when in the second engaged position.

1. Field of the Invention
The present invention relates generally to motor vehicle anti skid devices and, more specifically, to an apparatus attached to the undercarriage of a motor vehicle and activated by a user within the motor vehicle to extend until at least a portion thereof engages an icy surface whereby the apparatus will provide a resistance to lateral movement by the motor vehicle.
2. Description of the Prior Art
Numerous devices which modify the existing systems of steering, acceleration and especially braking, such as the anti locking braking system, for attempting to avoid the loss of control of a motor vehicle on wet and icy surfaces exist. These systems do not have the sole purpose of engaging upon entering hazardous icy portions of a roadway to resist lateral forces acting on a vehicle when on the icy surface which would normally cause the vehicle to skid and possibly spin.
A conventional motor vehicle 10 is illustrated in FIGS. 1 and 2 without an anti ice skidding apparatus as disclosed by the present invention. This vehicle 10 is traveling on a roadway 12 and is approaching a patch of ice 14. As can be seen from FIG. 2, when the motor vehicle 10 reaches and begins to travel over the patch of ice 14, the tires 16 lose a great deal of traction. While on this patch of ice, lateral forces as indicated by the dashed arrows labeled with the numeral 18 act thereon causing the vehicle 10 to skid and slide. The lateral forces 18 arc due to the limited amount of traction and cause the motor vehicle 10 to slide as indicated by the dashed outline of the motor vehicle indicated by the numeral 20. When a motor vehicle 10 is subject to and unable to resist these lateral forces the motor vehicle may slide off the roadway 12 and into objects such as trees 22 on the side of the roadway 12, slide into another motor vehicle sharing the roadway 12 or even spin out. Any of these situations may cause painful and possibly critical injuries to the occupants of the vehicle 12.
It is thus desirable to provide a device which may be attached to an undercarriage of a motor vehicle and is selectively deployed by the operator of the motor vehicle to provide a resistance to lateral movement of the vehicle. It is further desirable to provide a device which is able to control the direction of a motor vehicle while on an icy surface. It is still further desirable to provide a device which will not impede the momentum of the motor vehicle while resisting the lateral forces encountered while traveling on an icy surface. It is even further desirable to provide an anti ice skidding apparatus which is able to provide a breaking force for aiding the motor vehicle in braking on an icy surface.