The present invention relates to a nitride semiconductor laser device having a structure in which two or more of nitride semiconductor laser elements, having at least a first electrode on a first main surface of a first conductive type conductive substrate, having at least a first conductive type nitride semiconductor layer, an active layer, a second conductive type nitride semiconductor layer, and a second electrode on a second main surface of the conductive substrate, and having a stripe-waveguide structure parallel to the first main surface, are arranged in a direction parallel to the first main surface and a direction perpendicular to the direction of light that is emitted from the stripe waveguide structure in the nitride semiconductor laser device, and the first sub-mount and the first electrode of the nitride semiconductor laser element are electrically and heat-conductively connected, and the second sub-mount and the second electrode of the nitride semiconductor laser element are electrically and heat-conductively connected.

1. Field of the Invention
The present invention relates to a nitride semiconductor laser device, and also to a nitride semiconductor laser device that is provided with a nitride semiconductor laser element having a high output.
2. Description of the Background Art
A high output semiconductor laser element can obtain a watt-level output of light. Such semiconductor laser element can be used in a processing field, a medical field, and the like using a laser beam.
Further, in recent years, development of a nitride semiconductor laser element that emits a purple-blue laser beam for pickup of an optical disk has been carried out, and it is coming to a stage of practical use. However, at present, among the semiconductor laser elements, a nitride semiconductor laser element that can obtain a watt-level output of light has not come to a stage of practical use yet. The wavelength of the purple-blue laser beam in the nitride semiconductor laser element is as short as about 400 nm. Therefore, the development of a nitride semiconductor laser element having a high light output is desired from a viewpoint of widening the application range of the processing field and the medical field using a laser beam.
Further, in recent years, an illumination device in which a semiconductor light emitting element and a phosphor are combined and used has been developed to use in place of a conventional illumination device such as an incandescent lamp or a fluorescent tube, and some of them are put to practical use. One example of the semiconductor light emitting element is a light emitting diode having a III-V group compound semiconductor as a light emitting layer. The light emitting diode can emit light of various colors such as red light, blue light, and white light.
An illumination device using a light emitting diode has advantages that it is small in size, inexpensive, low in power consumption, and long in life compared with a conventional illumination device such as an incandescent lamp or a fluorescent tube. However, an illumination device using the light emitting diode cannot obtain as large an output as the conventional illumination device. Then, at present, an illumination device using the light emitting diode is mainly used no more than as back light, an illumination, or an indicator of a display.
Here, in the case of using the above-described nitride semiconductor laser element having a watt-level output of light as a light source of the illumination device, the electricity-light conversion efficiency as a light source is extremely high compared with the case of using a light emitting diode as the light source of the illumination device, and it is expected that a drastically higher output can be achieved.
In the case of using a nitride semiconductor laser element as the light source, the light output that is obtained from the light source is about 0.3 to 1 W (for example, 0.5 W). Then, in order to realize stable operation at which the light output of the nitride semiconductor laser element is 1 W or more, it is necessary to electrically connect two or more nitride semiconductor laser elements on one sub-mount in plurality.
Further, in order to operate the nitride semiconductor laser element by stabilizing the light output of the nitride semiconductor laser element at 1 W or more as described above, it is necessary to apply a current of about 0.5 A per nitride semiconductor laser.
In addition, the voltage that is necessary to operate the nitride semiconductor laser element is 3.5 V to 6 V. On the other hand, the voltage that is necessary to operate a general semiconductor laser element other than the nitride semiconductor laser element is 1.8 V to 2.5 V. Therefore, the voltage that is necessary for the operation of the nitride semiconductor laser element is high compared with the voltage that is necessary for the operation of the general semiconductor laser element, and the power that is necessary for the operation of the nitride semiconductor laser element is 0.5 A×5 V or more.
At this time, a large part of the power that is not converted into the light output of the power that is input into the nitride semiconductor laser element is converted into heat. The heat raises the temperature of the nitride semiconductor laser element, and not only are oscillation characteristics such as the light output and the oscillation wavelength affected, but also the heat affects seriously the life of the nitride semiconductor laser element. Therefore, when the nitride semiconductor laser element is packaged in a package, or the like, it is considered to improve thermal radiation characteristics of the nitride semiconductor laser element. For example, an arrangement in which a p-n junction plane side of the nitride semiconductor laser element is bonded to the sub-mount, that is, a so-called junction down arrangement, exposing a back surface side of a substrate of the nitride semiconductor laser element, can be adopted. Further, a structure of a semiconductor laser device using a plurality of heat sinks has been developed (for example, Japanese Patent Laying-Open No. 2005-032937).
Further, the semiconductor laser device in which a plurality of the semiconductor laser elements are packaged in order to obtain a high light output is investigated in Non-Patent Document 1 (Electronics Letters, October 2005, Vol. 41, No. 21, pp. 1172-1173) for example. In Non-Patent Document 1, a plurality of semiconductor laser elements are arranged on the sub-mount in a state that they are not separated into individual elements.
FIG. 13 is a schematic drawing showing a configuration of the nitride semiconductor laser device that is conventionally investigated. The nitride semiconductor laser device shown in FIG. 13 is packaged with a so-called junction down arrangement in which the p-n junction plane side of a nitride semiconductor laser element 10001 is bonded to a sub-mount 10002. Here, sub-mount 10002 is bonded to a heat sink 10003 that is welded to a stem 10004.
FIG. 14 shows a thermal resistance circuit network in the nitride semiconductor laser device shown in FIG. 13. In the nitride semiconductor laser device shown in FIG. 13, generated heat 30001 in a light emitting region of the nitride semiconductor laser element passes through a thermal resistance 30002 from the light emitting region of the nitride semiconductor laser element to a sub-mount upper-side surface. Then, generated heat 30001 passes through a thermal resistance 30003 to a heat sink upper-side surface from thermal resistance 30002 to the sub-mount upper-side surface. Finally, generated heat 30001 is radiated from thermal resistance 30003 to the heat sink upper-side surface through a thermal resistance 30004 to a housing in which the nitride semiconductor laser device is stored.
Other than the thermal resistances shown in FIG. 14, a thermal resistance corresponding to a path in which the heat is radiated by natural cooling from the nitride semiconductor laser element and the surfaces of the sub-mount and the heat sink and thermal resistance corresponding to a thermal path between a plurality of the nitride semiconductor laser elements exist. However, because the thermal resistances that are not shown in FIG. 14 are normally negligibly small compared with the thermal resistances shown in FIG. 14, they are neglected.
FIG. 15 shows the current-light output (I-L) characteristic of the nitride semiconductor laser device shown in FIG. 13. The horizontal axis represents the current (I) applied to the nitride semiconductor laser device, and the vertical axis represents the light output (L) of the nitride semiconductor laser device. In the following, the relationship between the current and the light output is expressed as an I-L characteristic.
In FIG. 15, the nitride semiconductor laser device shows a linear I-L characteristic for a current value lower than a point 20001. However, it deviates from an extension of the linear I-L characteristic in the range from point 20001 to a point 20002. Then, the I-L characteristic from point 20001 to point 20002 shows that the increase rate of the light output to the applied current becomes small compared with the I-L characteristic up to point 20001.
The phenomenon shown in FIG. 15 has its origin in that a decrease of the light output is caused by increasing the temperature of the nitride semiconductor laser device due to the generated heat from the nitride semiconductor laser element. Furthermore, at a higher current value than at point 20002, deterioration occurs of the nitride semiconductor laser device originated from the generated heat from the nitride semiconductor laser element, and an increase in the light output of the nitride semiconductor laser device shows saturation. Then, even when a current higher than at point 20002 is applied, the light output of the nitride semiconductor laser device shows a tendency of decreasing due to the deterioration of the nitride semiconductor laser device originated from an increase in the generated heat from the nitride semiconductor laser element.


A magnetic memory device may include a lower electrode on a substrate, a memory element on the lower electrode, an upper electrode on the memory element, and a protection spacer enclosing a portion of a side surface of the lower electrode and protruding laterally from the side surface of the lower electrode. The protection spacer may have a bottom surface that is positioned at a level higher than that of a bottom surface of the lower electrode.

Example embodiments of the inventive concept relate to a magnetic memory device, and in particular, to a magnetic memory device with a magnetic tunnel junction.
To keep up with the trend of higher speeds and lower power consumption, memory devices in electronic appliances need a relatively high read/write speed and relatively low voltage. Magnetic memory devices have been developed to satisfy that need. The magnetic memory devices are spotlighted as next generation memory devices because they have relatively high speed and/or nonvolatile characteristics.
A magnetic memory device may include a magnetic tunnel junction (MTJ). A magnetic tunnel junction may include two magnetic layers and a tunnel barrier layer interposed therebetween. Resistance of the magnetic tunnel junction may change according to the magnetization orientations of the magnetic layers. For example, the resistance of the magnetic tunnel junction may be higher when the magnetic layers have anti-parallel magnetization orientations than when they have parallel magnetization orientations. Such a difference in resistance can be used for data storing operations of a magnetic memory device. However, more research is still needed to mass-produce magnetic memory devices.


In order to reduce a steering torque during stoppage of a vehicle, according to the invention, opposite drive torques in normal and reverse directions are applied to a left rear wheel and a right rear wheel when a driver steers a steering wheel in a state where the vehicle stops, whereby a moment to turn the vehicle is generated, and an assist torque for steering the steering wheel is generated.

1. Field of the invention
The present invention relates to a power steering system for assisting steering force of wheels, and relates to a method of driving rear wheels with an effect of reducing a steering torque when steering a steering wheel during stoppage of a vehicle.
2. Description of related art
As a power assist device for assisting the force for steering the wheels in accordance with the steering torque input by a driver, a device using a hydraulic mechanism is general. As an example of this prior art, there is the one in which a hydraulic pressure is generated by driving an oil pump with an electric motor, and the generated hydraulic pressure is controlled by feeding back and controlling the steering torque input from the steering wheel to generate the steering assist force (see JP-A-2003-212141, for example).
In addition, an electric power steering system for assisting the steering only by an electric motor without using a hydraulic mechanism has come to be widely used, mainly in a compact car (see JP-A-8-295257, for example).
Further, there is known an art relating to a hybrid electric hydraulic power steering device capable of realizing energy saving and space saving by using an oil pump capable of discharging an operating oil in both directions to drive a motor on demand (see JP-A-2000-168604, for example).
It is generally known that the steering force in the case of steering the steering wheel when the vehicle is stopping is larger than that in a state where the vehicle is running. Accordingly, the maximum assist force which should be generated by the power steering system is specified by the steering assist force required at the time of stoppage of the vehicle (see "Automobile Steering System and Driving Stability" edited by Kayaba Industry Co., Ltd., P. 213, Sankaido Publishing Co., Ltd., for example).


A semiconductor processing method of forming field isolation oxide relative to a silicon substrate includes, i) rapid thermal nitridizing an exposed silicon substrate surface to form a base silicon nitride layer on the silicon substrate; ii) providing a silicon nitride masking layer over the nitride base layer, the base and masking silicon nitride layers comprising a composite of said layers of a combined thickness effective to restrict appreciable oxidation of silicon substrate thereunder when the substrate is exposed to LOCOS conditions; and iii) exposing the substrate to oxidizing conditions effective to form field isolation oxide on substrate areas not masked by the base and masking silicon nitride layers composite. Further, a semiconductor processing method of forming field isolation oxide relative to a semiconductor substrate includes, a) masking a first portion of a semiconductor substrate with a composite comprising a first nitride layer, a polysilicon layer over the nitride layer, and a second nitride layer over the polysilicon layer; and leaving a second portion of the semiconductor substrate unmasked by said composite; and b) exposing the semiconductor substrate to oxidizing conditions effective to form field isolation oxide in the second substrate portion.

The reduction in memory cell and other circuit size required for high density dynamic random access memories (DRAMs) and other circuitry is a continuing goal in semiconductor fabrication. Implementing electric circuits involves connecting isolated devices through specific electric paths. When fabricating silicon and other material into integrated circuits, it is necessary to isolate devices built into the substrate from one another. Electrical isolation of devices as circuit density increases is a continuing challenge.
One method of isolating devices involves the formation of a semi-recessed or fully recessed oxide in the nonactive (or field) area of the substrate. These regions are typically termed as "field oxide" and are formed by LOCal Oxidation of exposed Silicon, commonly known as LOCOS. One approach in forming such oxide is to cover the active regions with a layer of silicon nitride that prevents oxidation from occurring therebeneath. A thin intervening layer of a sacrificial pad oxide is provided intermediate the silicon substrate and nitride layer to alleviate stress and protect the substrate from damage during subsequent removal of the nitride layer. The unmasked or exposed field regions of the substrate are then subjected to a wet H.sub.2 O oxidation, typically at atmospheric pressure and at temperatures of around 1000.degree. C., for two to four hours. This results in field oxide growth where there is no masking nitride.
However at the edges of the nitride, some oxidant also diffuses laterally. This causes the oxide to grow under and lift the nitride edges. Because the shape of the oxide at the nitride edges is that of a slowly tapering oxide wedge that merges into another previously formed layer of oxide, it has commonly been referred to as a "bird's beak", The bird's beak is a lateral extension or encroachment of the field oxide into the active areas where the devices are formed. Although the length of the bird's beak depends upon a number of parameters, the length is typically from 0.05 micron-0.15 micron per side.
This thinner area of oxide resulting from the bird's beak provides the disadvantage of not providing effective isolation in these regions, and as well unnecessarily consumes precious real estate on the semiconductor wafer. Further, as circuit density commonly referred to as device pitch falls below 1.0 micron, conventional LOCOS techniques fail due to excessive encroachment of the oxide beneath the masking stack. The closeness of the masking block stacks in such instances can result in effective joining of adjacent bird's beaks, thus effectively lifting the masking stacks and resulting in no masking effect to the oxidation.
Also, considerable undesirable stresses are created beneath the nitride at the silicon interface when oxidation occurs. These stresses are in large part due to the formed SiO.sub.2 consuming 2.4 times the volume as elemental silicon it replaces. The pad oxide layer absorbs some of this stress, but additional techniques have been utilized. One such technique used to further alleviate the stress during LOCOS is to use a thin layer of polysilicon which is interposed between the pad oxide layer and the overlying nitride. The goal is to have some of the stress, which would otherwise be subjected upon the silicon substrate, occur in the deposited polysilicon layer. A significant problem, however, is that the polysilicon at the edges of the nitride mask will itself oxidize, forming SiO.sub.2 which is the same composition as the field oxide regions. Such oxidized polysilicon regions are not practically removable, and undesirably result in increased volume of oxide in the bird's beak regions.
The SILO (sealed-interface local oxidation) process is another modification of typical prior art LOCOS processes. In SILO, a thin layer of silicon nitride is formed on the silicon surface. A pad oxide layer (SiO.sub.2) and a nitride film are subsequently deposited. This three layer composite is then photopatterned and etched to overlie desired active area regions and leave desired field oxide regions exposed. The nitride layer is intended to seal an interface between it and the silicon substrate surface to restrict lateral diffusion of oxidants during LOCOS, and thus reduce bird's beak encroachment.
It would be desirable to develop alternate techniques.

Semiconductor processing method of forming field isolation oxide relative to a semiconductor substrate


Provided is a detector system for detecting a plurality of items each having at least one RFID tag attached thereto. The detector system may include a presence detector and/or a message detector. The presence detector may include a signal reader which receives modulated carrier frequencies from the RFID tags during a predetermined response time period for comparison to a reference level. The signal reader may be configured as a power integrator or a constellation discriminator. The power integrator sums the power contained in signals transmitted by the RFID tags by integration for comparison to an environmental noise level measurement taken during a quiet period. For the constellation discriminator, bits contained in the modulating message are compared to the bit pattern of a predetermined reference constellation. The detector system may be configured as a 3-state detector which combines the presence detector with a message detector that indicates the identification code of the RFID tags.

The present invention relates to radiofrequency identification (RFID) markers for detection of surgical implements and, more particularly, to an RFID marker embedded in or otherwise securely attached to a surgical implement such as a laparotomy pad or sponge, metallic surgical instrument or other implement and which is specifically adapted for preventing the inadvertent retention of such implement(s) during a surgical procedure.
Included in the prior art are many patents that disclose systems and methods for detection of surgical implements following surgery prior to wound closure. Such detection methods incorporate x-ray opaque markers within surgical implements and effect detection using postoperative x-ray of the patient or of discarded sponges. Also disclosed for detection of surgical implements are methods involving use of resonant tags made from magnetomechanical elements, capacitors, LRC oscillatory circuits and smart markers.
U.S. Pat. Nos. 4,114,601 and 4,193,405 to Abels disclose a medical and surgical implement detection system. Surgical implements such as metallic instruments, sponges, implantable devices and indwelling therapeutic devices and materials are detected within the human body or other area of interest by incorporating or adding a radiofrequency transponder. A microwave system mixes two fundamental microwaves having 4.5-5 GHZ frequencies and relies on a non-linear transponder to produce higher order product frequencies. The transponder may be a thin film of a ferrite material exhibiting gyro-magnetic resonance at selected frequencies or a solid-state device containing diodes and field effect transistors. A non-linear transponder signal is received by a receiving antenna and filtered to remove all fundamental microwave frequencies. Unfortunately, substantially all of the higher order microwave frequencies generated by the transponder are readily absorbed by the human body. Consequently, most of the higher order microwave frequency signals are lost before any non-linear transponder can be detected. In addition, the gyro-magnetic effect produces a relatively weak signal.
U.S. Pat. No. 4,658,818 to Miller, Jr., et al. discloses an apparatus for tagging and detecting surgical implements. A miniature battery-powered oscillator is attached to each surgical implement and activated prior to its initial use. The output of each oscillator has the form of a low powered pulse of 1-10 MHZ frequency, and is coupled to the body's fluids and tissue. Following surgery but prior to suturing, a detection system senses for any pulses generated by the oscillator within the body. The surgical implement detection system disclosed by the '818 patent is not passive. It requires a miniature battery, which is turned on at the beginning of the operation. When the operation is complete, the battery may have already discharged, in which event the surgical implement will not be detected by the apparatus.
U.S. Pat. No. 5,057,095 to Fabian discloses a surgical implement detector utilizing a resonant marker for use in human or animal tissue. The marker is triggered into resonance by the interrogating field. A resonance frequency signal emitted by the marker is detected by a separate detection circuit adjacent to the interrogating circuit. The marker resonates due to magnetostriction properties of an amorphous metal ribbon, a piezoelectric device or a tuned LRC circuit. The response from the marker constitutes a simple sine wave having a particular frequency, which is less than one gigahertz. A detector is responsive within an interrogation zone encompassing a surgical wound. The marker is adapted to undergo resonance solely at a pre-selected frequency below 1 GHz, causing a substantial change in its effective impedance. An electromagnetic dipole field is thereby generated, which produces an identifying signal identity. The interrogation means is also provided with a means for varying phase and/or direction of the interrogating field. A receiving means placed within the interrogation zone detects the "ring-down", phase-shift, impedance or other identifying characteristic of the element in resonance.
U.S. Pat. No. 5,188,126 to Fabian, et al. discloses a surgical implement detection system utilizing capacitive coupling for use in human or animal tissue. The system comprises a battery-powdered marker, which is secured to the surgical implement and positioned within a surgical wound. A detection means has an antenna disposed in close proximity of the tissue. Means are provided for capacitance coupling of the marker with the antenna and activation of the battery-powered marker. A field generating means associated with the detection system generates an electromagnetic field having a predetermined frequency band ranging from about 10 MHz to 1 GHz. The electromagnetic field causes the marker to produce a signal in the form of a sinusoidal wave having unique signal identity. A battery powers the capacitive marker, which will not function when the battery is discharged. Inasmuch as there is no means to verify the status of the battery, this method for detection of surgical implements is vulnerable to battery failure.
U.S. Pat. No. 5,190,059 to Fabian, et al. discloses a surgical implement detector utilizing a powered marker for use in human or animal tissue. A battery-powered marker is secured to a surgical implement positioned within the wound. An electromagnetic field generating structure in the battery-powered marker is provided for generating within the transmitting zone an electromagnetic field having a predetermined frequency band, providing the marker with signal identity. The response from the battery-powered marker is a simple sine wave having a particular frequency. Such a response does not comprise a digital code as it lacks the capacity for identifying a surgical implement. Battery power is required such that detection is not effected when the battery is discharged.
U.S. Pat. No. 5,541,604 to Meier discloses transponders, interrogators, systems and methods for elimination of interrogator synchronization requirement. A Radiofrequency Identification (RFID) system has an interrogator and a transponder, the interrogator having a first tuned circuit of a powering frequency for sending a powering burst to a transponder, a filter/demodulator for receiving a wireless, modulated RF response from a transponder. The interrogator additionally has a second tuned circuit in electrical communication with a modulator. The second tuned circuit has a selected bandwidth about a communication frequency. The selected bandwidth does not substantially overlap the powering frequency and encompasses the bandwidth of the modulated carrier of the RF response. The carrier is modulated using pulse width modulation (PWM), pulse position modulation (PPM), frequency-shift keying modulation (FSK), or another type of modulation methods. The interrogator also has a controller in electrical communication with the filter/demodulator and the tuned circuits. It enables the first tuned circuit to send the powering burst during a first time period and enables the modulator in electrical communication with the second tuned circuit to receive the RF response during a second time period. The transponder has a tuned circuit. A tuning circuit in electrical communication with the tuned circuit modifies the frequency characteristics of the tuned circuit. The circuit is thereby tuned during the powering burst to the powering frequency. It is also tuned during the RF response to the communication frequency. The transponder also includes a demodulator in electrical communication with the tuned circuit for receiving the RF interrogation therefrom and for demodulating data from the RF interrogation. This current generation RFID device sends a preset code to the interrogator. It is powered entirely by the power burst signal provided in the first time period and is capable of transmitting the code at a high rate to the interrogator.
U.S. Pat. No. 5,664,582 to Szymaitis discloses a method for detecting, distinguishing and counting objects. A marker made from a nonmagnetostrictive strip of amorphous or crystalline material produces higher harmonic excitations when energized by an alternating magnetic field. The higher harmonics are detected by the exciting antenna. This passive, non battery-powered device receives a fixed second harmonic frequency sinusoidal signal based on the size, shape and material of the marker. Information is not digitally encoded and therefore the marker has no means for identifying individual counting objects.
U.S. Pat. No. 5,931,824 to Stewart, et al. discloses an identification and accountability system for surgical sponges and includes machine-readable information located on a plurality of surgical sponges used in the surgical procedure. At the end of an operation the surgical implements are machine read to determine whether any of the sponges are missing. The system also includes an x-ray detector for the detection of missing sponges. Detection of sponges placed within a surgical wound is not effected unless the absence of a sponge is detected during the sponge count procedure following surgery. Actual location of a missing sponge requires x-ray examination.
U.S. Pat. No. 6,026,818 to Blair, et al. discloses a tag and detection device. An inexpensive tag has the form of a ferrite bead with a coil and a capacitor, or a tag of flexible thread composed of a single loop wire and capacitor element. The detection device locates the tag by pulsed emission of a wide band transmission signal. The tag resonates with a radiated signal, in response to the wide band transmission. Resonation occurs at the tag's own single, non-predetermined frequency, within the wide band range. The pulsing action of the wide band transmission builds the non-predetermined, radiated signal intensity over the ambient noise levels. This radiated signal is a sinusoidal wave of non-predetermined frequency and does not have digital information that identifies a particular sponge or surgical pad.
U.S. Pat. No. 6,076,007 to England, et al. discloses surgical devices and their location. A surgical device, such as a catheter or a prosthesis, carries, at a predetermined location, a tag composed of a high permeability, low coercivity magnetic material having a magnetized bias element. The tag is interrogated with a rotating magnetic field. Interaction between the tag and the rotating magnetic field is detected by a flying null system to determine the location of the tag within the human or animal body. Typically, the marker will be in the form of a thin film, a wire or a strip. The response signal from the tag is a sinusoidal wave with no digital information. The detection system is based on flying null technology. The tag is used for locating a catheter tip, not a sponge or surgical pad within a surgical wound.
U.S. Pat. No. 6,424,262 and U.S. patent application No. 20040201479 to Garber, et al. disclose applications for radiofrequency identification systems. An RFID target is used, together with magnetic security element and a bar code reader, to check out and manage library materials such as reference books, periodicals, and magnetic and optical media. This disclosure has nothing to do with detecting sponges or surgical pads in a surgical wound.
U.S. Pat. No. 6,838,990 to Dimmer discloses a system for an excitation leadless miniature marker. An excitation field excites a leadless marker assembly. The system comprises a source generator assembly having a power supply, an energy storage device, a switching network and an untuned source coil interconnected and configured to deliver a selected magnetic excitation signal waveform, such as continuous bipolar or unipolar waveform, or a pulsed magnetic excitation signal waveform. The power supply is configured to deliver power to energize the energy storage device. The switching network is configured to: direct electrical current through the source coil. It alternately switches between a first on position and a second on position. Stored energy is alternately transferred from the energy storage device to the source coil and from the source coil back to the energy storage device. The source coil is coupled to the switching network to generate an excitation signal. Untuned excitation is used by the source coil to look for resonance from a set of markers embedded in human tissue. Information is processed using an array sensor to three-dimensionally locate a given marker. This system does not locate sponges or surgical pads misplaced in a surgical cavity. The frequency response of a target is sinusoidal and has no digital capability.
U.S. patent application No. 2002/0143320 to Levin discloses tracking medical products with integrated circuits. Radiofrequency identification devices comprising a microprocessor, memory, analog front end and antenna are used to communicate with a remote unit. The remote unit has a processor memory and transreceiver that receives digital data from radiofrequency identification devices attached to medical products, such as a pharmaceutical product, a blood product or a tissue product. The radiofrequency identification device is first scanned and then rescanned at the end of the surgical procedure. There is no indication that the radiofrequency identification devices are encapsulated. Neither is there any indication that the RFID devices are incorporated in a sponge, surgical pad or surgical implement. Further, there is no indication in the Levin application that the RFID devices are scanned during surgery to establish the location of the sponge or surgical pad. There is also no indication in Levin application that the RFID devices are scanned at the end of an operating procedure to establish that no sponges or surgical pads are left behind in a surgical cavity.
U.S. patent application No. 2003/0006878 to Chung discloses a smart tag data encoding method. Information is stored in a smart tag having a memory. The smart tag has two memory portions. One of the partitions is permanent and cannot be erased. A second memory portion stores application specific data. The second memory portion also stores a relational check number, which validates the integrity of the data stored in the second memory, thereby detecting memory alteration or corruption. This smart tag data encoding method has nothing to do with detecting a sponge or surgical pad left behind in a surgical wound.
U.S. patent application No. 2003/0057279 to Uozumi et al. discloses an identifying system for an overlapped tag. An RFID and one or more resonance capacitors connected through on-off switches may be turned on or off by a remote control circuit. The overlapping tags may be interrogated using an RFID system, or one more resonance capacitors. The Uozumi et al. system does not detect sponges and surgical pads in a surgical wound, since they are not expected to overlap. Signals from the resonant capacitors of Uozumi et al. form a sine wave comprising electromagnetic radiation and do not carry a digital code
U.S. patent application No. 20030066537 to Fabian, et al. discloses a surgical implement detection system. Surgical implements used during an operating procedure are detected in human tissue. Markers attached to the surgical implements change their impedance at a preselected frequency in the presence of an electromagnetic field. The system uses a magnetomechanical element which vibrates at a preselected frequency when excited. This preselected frequency, when detected, indicates the presence of a surgical implement to which the magnetomechanical marker element is attached. The marker resonates only at a fixed frequency and provides no digital information suited for identifying a sponge or a surgical pad.
U.S. patent application No. 20030105394 to Fabian, et al. discloses a portable surgical implement detector. Surgical implements used during an operating procedure are detected in human or animal tissue. Markers attached to the surgical implements change their impedance at a preselected frequency in the presence of an electromagnetic field. Each of the markers is thereby provided with signal-identifying characteristics. The portable detector sweeps the surgical cavity with a range of frequencies which excites and vibrates markers attached to surgical implements at preselected frequencies, causing their detection. The markers resonate at preselected frequencies in the form of sinusoidal waves, but do not provide digital data suited for identifying a sponge or surgical pad.
U.S. patent application No. 20030192722 to Ballard discloses a system and method of tracking surgical sponges. The sponges have a radiopaque object embedded therein which is visible when the sponges are x-rayed. All sponges removed from the surgical wound are placed into a sponge container which is provided with an internal device to x-ray and identify the sponges after use. However, because the sponges are not x-rayed when first put into use and because it is not possible to x-ray the sponges when they are in the patient wound, the Ballard system is incapable of determining whether all sponges have been removed from the patient wound or whether any sponges have been left behind in the patient wound.
U.S. patent application No. 20040129279 to Fabian, et al. discloses a miniature magnetomechanical tag for detecting surgical sponges and implements. This tag is a magnetomechanical device and is excited by the interrogating magnetic field. The interrogating field is switched off, and the ring down characteristic of the resonant target is detected. The system does not provide digital means for identifying a sponge or surgical pad.
U.S. patent application No. 20040250819 to Blair, et al discloses an apparatus and method for detecting objects using tags and a wideband detection device. An apparatus and method for the detection of objects in the work area, such as surgical sites, including a detection tag affixed to objects used during surgery, is disclosed. The apparatus and method feature interrogates with a transmitter emitting a pulsed wideband signal, prompting the tag element to provide a return signal, which is received and analyzed. The device features an antenna portion containing a single or a plural ring-shaped antenna. Also, the pulsed wideband interrogation signal may be pulsed-width modulated or voltage-modulated. The pulsed signals trigger a continuing response signal from the tag in its response frequency range, which increases in intensity to the point where it becomes differentiable from background noise and is detected within the wideband range by the signal detector as an indication of the presence of the tag. The tag is excited by a wide band pulsed interrogation signal, which builds up the output of the tag and can be detected over ambient electronic noise. The tag signal has a predetermined frequency in the form of a sinusoidal wave, and does not carry digital information suitable for identifying laparotomy pads or sponges retained within the wound cavity.
U.S. patent application No. 2005/0003757 to Anderson discloses an electromagnetic tracking system and method having a single-coil transmitter. The system includes a single coil transmitter emitting a signal, a receiver receiving a signal from the single coil transmitter, and electronics for processing the signal received by the receiver. The electronics determine a position of the single coil transmitter. The transmitter may be a wireless or wired transmitter. The receiver may be a printed circuit board. The electronics determine position, orientation, and/or gain of the transmitter. The single coil transmitter is a powered device and may be wired or wireless. It is not a passive device that can be incorporated in a sponge or surgical pad due to the requirement for a reliable power source.
PCT patent application No. WO 98/30166 to Fabian et al. discloses a surgical implement detector utilizing a smart marker. The surgical implement is appointed for disposition within human or animal tissue and is made to be electronically identifiable by affixing thereto a smart marker, which is an unpowered integrated circuit with EEPROM memory carrying a code. When the smart marker is sufficiently close to the reader antenna, a voltage is generated within the marker antenna that charges the capacitor and powers the integrated circuit. A switch is opened and closed to transmit the stored code in the EEPROM memory, providing identification and recognition of a smart target attached to a surgical sponge. The marker antenna operates at a frequency of near 125 KHz. The frequency of information transfer to the reader is very slow, due to the switching on and off action.
Despite the above noted deficiencies associated with RFID devices, certain industries have successfully implemented such technology for various purposes. For example, RFID technology has been successfully used to track cattle by the placement of RFID tags on cattle ears. The RFID tags may be read automatically or manually by a hand-held scanner in order to identify individual cattle. The cattle's identity may be linked to a computer database allowing access to a large amount of detailed information regarding the animal's origin, breeding, age and weight. Furthermore, such RFID tags may be utilized to identify the proximity of certain cattle to a feeding trough. Such RFID tags can be active, passive, or semi-active. Unfortunately, RFID systems such as those used in cattle tracking suffer from several critical deficiencies that detract from their overall utility. For example, RFID systems designed for cattle identification are understood to be limited to a range of just a few inches. Unfortunately, in surgical applications, a greater range is required. More specifically, in surgical applications, a range of at least 8 inches or more is required in order to adequately scan a patient's wound from above and reliably detect the presence of an RFID tag to which a surgical device may be attached.
Another deficiency of prior art RFID systems is that they are optimized to identify one or more RFID tags which are harmless to the environment being interrogated such as in a cattle yard, on a warehouse pallet, or in toll booth lane. In this regard, the primary goal of most RFID systems of the prior art is to successfully collect an identification message from the RFID tag. Detecting the mere presence of an RFID tag is typically of secondary importance.
However, in the surgical environment, these priorities are reversed. More specifically, in a surgical environment, it is of primary importance to detect the presence of all RFID tags such that the items to which they are attached may be removed from the patient wound. It is of secondary importance to identify the RFID tag. As such, the unique priorities of surgery means that the application of RFID detection systems for the surgical environment may involve non-obvious methodologies and system configurations.
Although at higher frequencies, (typically 13.56 MHz, 850 to 950 MHz, or 2.45 GHz), the added bandwidth permits the processing of multiple RFID tags at one time, RFID systems that operate in the low frequency ranges such as at 125 kHz typically allow for the stimulation of only one nearby RFID tag at a time. Once the RFID tag is stimulated, a signal reader may then retrieve a digital ID code impressed upon the signal. Unfortunately, the presence of two or more RFID tags within range of the detector generally results in a failure to acquire identification codes from any of the RFID tags due to "data collision" between the RFID tags. In this regard, current RFID readers are generally incapable of determining the presence of multiple RFID tags within a scanned area or of determining the identification code of any one of the RFID tags in an area containing multiple RFID tags.
The above-mentioned deficiencies of current RFID readers could unfortunately mean that either two or more RFID tags are present in the area, or, that there are no RFID tags present in the area being scanned. As such, there is currently no reliable method using conventional RFID tagging technology to verify whether or not surgical items are present after the end of an operation (i.e., prior to wound close) absent the incorporation of more expensive collision-control RFID tag technology. The failure to adequately identify and remove such items prior to wound closure is fairly widespread and well-documented in medical literature. Unfortunately, inadvertent retention of surgical items in the patient can result in serious complications for the patient and even death.
Another deficiency of prior art RFID systems is that the range of RFID tag detection is dependent upon the degree to which the RFID reader and the RFID tag are aligned with one another. When the antenna coils of the RFID tag and the RFID reader are aligned for best energy coupling, detection range is as much as 50-100% greater than when the antenna coils are oriented at 90° relative to one another. Unfortunately, there is no way to determine the orientation of the RFID tag which may be hidden from view in the patient wound. Therefore, detecting a tagged surgical item may be unsuccessful if the RFID reader antenna is not optimally-oriented with respect to the unseen RFID tag.
As so noted, the ability to detect an RFID tag may be compromised due to misalignment between the RFID tag antenna and the remote detector unit antenna. The occurrence of this event has been very low (less than 5 percent) and does not occur when individual readings are obtained. Nonetheless, to counteract the possibility of misalignment, the installation of two or more RFID tags on the same surgical implement may eliminate this event. Unfortunately, the installation of multiple RFID tags on the same surgical implement will result in data collision between the RFID tags and therefore requires that anti-collision measures be taken.
One solution to the above-mentioned problem is the incorporation of anti-collision technology. More specifically, with anti-collision technology, an identification code may be retrieved from two or more RFID tags in a scanned area during simultaneous interrogation of multiple RFID tags. Such anti-collision technology operates by delaying the response of each RFID tag by an appropriate amount of time in order to avoid simultaneous responses at the signal reader which, in turn, avoids corruption of signal data from the RFID tags. Unfortunately, this delay in RFID tag response increases the power requirements for each RFID tag. In a passive system, a limited amount of power is typically collected from the signal transmitted by the RFID reader (i.e., interrogator) such that a battery may be additionally required to provide power for the extended duration due to signal delay.
In addition to the added power requirements, a further deficiency associated with anti-collision technology is that such systems are typically more costly than RFID tag systems that operate on a one-at-a-time basis because they require the tags to have read/write capability. The increased cost of anti-collision technology in the RFID detection system may be prohibitive when the instrument or implement to which an RFID tag is attached is less expensive than the RFID tag itself.
As can be seen, there remains a need in the art for a highly reliable, surgical implement detection system wherein RFID tags may be attached to laparotomy pads or sponges and other non-metallic items as well as metallic instruments or implements for detection thereof. Preferaby the surgical implement detection RFID tag is passively powered (i.e., non-battery powered). Also needed is a marker of the type described above which can withstand cleaning and sterilization procedures commonly employed, and resists exposure to body fluids such as blood or saline solutions. Additionally, a surgical implement marker and corresponding detection device, is needed to provide a reliable indication of the location of foreign objects within a surgical wound during and at the completion of a surgical procedure prior to wound closure.
Furthermore, there exists a need in the art for a reliable detector system that utilizes RFID technology and which is specifically configured to provide an indication about the presence of multiple RFID tags in a specific area such as within a surgery wound. More specifically, there exists a need in the art for an RFID detector system that is capable of indicating whether one or more RFID tags are present within a given range or, alternatively, whether no RFID tags are present within the range. Even more specifically, there exists a need in the art for an RFID detector system that accurately and reliably detects the mere presence of one or more RFID tags within a surgical wound and preferably at a range of at least 8 inches with at least a 95 percent probability of an accurate determination of presence or non-presence.
Also, there exists a need in the art for an RFID detector system that allows for an indication of the surgical implement or instrument (i.e., via the identification code of the RFID tag) once located such that the surgical item can be inventoried. Additionally, there exists a need in the art for an RFID detector system that preferably operates at a relatively low frequency such as at 125-134 kHz in order to minimize the detrimental effects encountered in the upper frequencies, including increased signal attenuation by body tissue and nearby metallic objects. In addition to these disadvantages encountered in the upper frequency range, further drawbacks are encountered as the Gigahertz range is approached. As is well known in the art, microwave ovens typically operate at this frequency to heat watery foods and can therefore potentially cause unwanted localized heating (i.e., cooking) of body tissue by inducing rapid vibration of water molecules contained therewithin. The low frequency range, on the other hand, is not only less affected by intervening tissue and metal, but has the added benefit of avoiding issue heating. Lastly, there exists a need in the art for an RFID detector system that is of low cost such that the detector system is feasible for implementation in hospitals having large quantities of surgical items and implements.


A magnetic flowmeter (8) for measuring the flow of a flowing medium having a measuring tube (1) with a cross section that changes along its length and preferably the cross section in the middle section of the measuring tube (1) is less than at the beginning and end of the measuring tube (1), preferably the cross section of the measuring tube (1) is rectangular in its middle section and wherein the housing (2) preferably has a circular cross section. The inlet section (5) of the measuring tube (1) is formed of two segments (5a and 5b), of which a first segment (5a), in terms of flow direction, has a cross section that increases in the direction of flow and a downstream adjoining second segment (5b) has a cross section that decreases in the direction of flow. Optionally, the outlet section (6) is similarly formed of two sections (6a, 6b).

1. Field of the Invention
The invention relates to a magnetic flowmeter for measuring the flow of a flowing medium having a measuring tube, a unit for generating a magnetic field that generates a magnetic field at least partially permeating the measuring tube, two electrodes for detecting a measuring voltage induced in the flowing medium and a housing incorporating the measuring tube, preferably also the unit for generating a magnetic field and the electrodes, wherein the measuring tube has a cross section that changes over its length and preferably the cross section in the middle section of the measuring tube is less than at the beginning and end of the measuring tube, preferably the cross section of the measuring tube is rectangular in its middle section or square and wherein the housing preferably has a circular cross section.
2. Description of Related Art
Magnetic flowmeters have been known extensively from the prior art for decades; see, Technische Durchflussmessung" by Prof. Dr.-Ing. K. W. Bonfig, 3. Edition, Vulkan-Verlag Essen, 2002, pages 123 to 167 for a description.
The basic principle of a magnetic flowmeter for measuring the flow of a flowing medium goes back to Faraday, who, in the year 1832, suggested using the principle of electrodynamic induction for measuring the velocity of flow of a flowing medium. According to Faraday's law of induction, electrical field intensity is created perpendicular to the direction of flow and perpendicular to the magnetic field in a flowing medium that carries charge carriers along with it and flows through a magnetic field. Faraday's law of induction is used by magnetic flowmeters in that a magnetic field is created by a unit for generating a magnetic field, which normally has two magnetic coils supplied with current, and at least partially lead through a measuring tube, wherein the generated magnetic field has at least one component that runs perpendicular to the direction of flow. Within the magnetic field, each volume element of the flowing medium having the field intensity created in this volume element moving through the flowing medium and having a certain number of charge carriers contributes to a measuring voltage that can be detected via the electrodes.
As an example of the magnetic flowmeters that form the basis of this invention, German patent disclosures 197 08 857; 10 2004 063 617 and corresponding U.S. Pat. No. 7,261,001 B2; German patent disclosure 10 2008 057 756 and corresponding U.S. patent application 2010/132478 A1 are cited here. The content of these disclosures is hereby specifically incorporated by reference into the present application.


The invention relates to a cold sales cabinet for conserving foodstuffs. It applies to cabinets having means for circulating a flow of air and associated with an internal or an external refrigeration unit. A cold sales cabinet of the invention is characterized in particular in that it comprises at least one enclosure (12) containing an evaporator (2), said enclosure being provided with microwave energy transmission means (10) and presenting two opposite walls (15, 16) that are proof against microwave radiation and not airtight. The microwave radiation is used to limit quickly and cheaply phenomena of frosting or icing on the evaporator (2) so as to improve refrigeration performance.

The present invention relates to a device for simultaneously improving the performance of cabinets, windows, counters, chests, stalls, or units for displaying and selling foodstuffs that are conserved at a temperature lower than ambient temperature. Refrigerated or deep-freeze cabinets are in very widespread use in stores for dispensing foodstuffs, in pharmaceutical outlets, or more generally whenever it is necessary to conserve goods at a temperature lower than ambient. In the text below, refrigerated or deep-freeze cabinets, windows, counters, chests, stalls, or units are referred to generically as xe2x80x9ccold sales cabinetsxe2x80x9d.
In the present state of the art, refrigerated cabinets, windows, or counters, and more particularly so-called xe2x80x9copenxe2x80x9d cabinets, all present the feature of operating by virtue of curtains of refrigerated air subjected to forced circulation along the open face. Said open face can be horizontal or vertical. Whatever the precautions taken to guide such curtains of air, it is found that some mixing takes place between the refrigerated air and the air of the premises in which said cabinets are placed. A consequence of this partial mixing is that a significant quantity of water vapor is contained in the flow of air driven by the fans and put into thermal contact with the evaporator of a cold sales cabinet. This water vapor is inevitably trapped at said evaporator where it becomes deposited as a progressive buildup of ice. This buildup of ice has the effect of progressively constituting an insulating sheath around the evaporator and its fins, thereby reducing the heat exchange coefficient between said element and the circulating air, and also increasing head losses, thereby significantly reducing the flow rate of refrigerated air.
After cold sales cabinets have been in operation for a few tens of minutes (which period is a function of the humidity of the ambient air, the dew point temperature, and the evaporation temperature of the refrigerating fluid), a significant drop is observed in the efficiency of the curtain of air, and consequently a rise is observed in the temperature of the inside of the cabinet and of the foodstuffs it contains.
To combat that phenomenon of frost appearing and the associated losses of performance, various solutions have been proposed which have turned out to be relatively unsatisfactory.
Firstly, it has been proposed to warm up the evaporator periodically, either by stopping the circulation of refrigerating fluid within said component, or by providing it with heater cords or electric resistances, or indeed by heating the air (WO 98/06987 to Hislop, FR-2 610 708 to Bosch Siemens, EP-0 768 053 to Sanyo, EP-0 403 459 to Electrolux).
Proposals have also been made to duplicate the evaporator, with one of the elements being defrosted while the other one is in operation (WO 94/26154 to Hussmann).
Proposals have also been made to dehumidify the air prior to passing over it over the evaporator (application No. 91/09664 - 2 679 988 to A.R.M.I.N.E.S.).
Proposals have also been made to build up a store of low temperature, using a large mass of ice or a eutectic for the purpose of taking over from the evaporator for the length of time it requires to be defrosted (application No. 88/02314 - 2 611 383 to Toshiba).
Finally, numerous dispositions and combinations of single, double, or triple air curtains have been proposed in which said air curtains are either heated or cooled for the dual purposes of limiting uptake of water vapor in the flow of air and limiting condensation on the evaporator (WO 97/17003 to Bonnet Neve, EP-0 709 046 to Sanyo, FR-2 615 082 to Bonnet Refrigeration, WO 94/23620 to Northampton Refrigeration).
Proposals have also been made to defrost the evaporator by using jets of superheated gas or steam.
None of those solutions turns out to be genuinely satisfactory, whether from the point of view of the energy consumption of cold sales cabinets or the genuine performance of such apparatuses and their ability to keep foodstuffs under temperature conditions that comply fully with the legislation in force.
In terms of cost, it is found that the need to combat frosting phenomena on evaporators leads to evaporators, fans, and air circuits being over-dimensioned. The length and the frequency of the essential defrosting cycles in presently-available apparatuses are such that these pieces of equipment are used for their refrigeration function during less than 80% of their total operating time. The remainder of the time they are used for a function that is the exact opposite from that for which they are designed, i.e. to be subjected to or to cause heating which temporarily and partially cancels their effects. Experience shows that presently-manufactured and sold cold sales cabinets are subjected to large temperature variations over time, which makes it very difficult to comply with the standards in force; these variations are particularly large between the beginning and the end of the defrosting period, which period inevitably gives rise, in the present state of the art, to significant heating of the air curtain and thus of the foodstuffs. Experience also shows that in the present state of the art and regardless of the particular solution implemented to combat evaporator frosting phenomena, presently-manufactured and sold cold sales cabinets cannot provide a temperature that is uniform throughout their inside volume: the phenomenon of evaporator frosting does not take place identically on all parts of said element, so the resulting head losses are necessarily non-uniform, and as a result the temperature and the flow rate of the air curtain(s) are themselves non-uniform. This state of affairs leads to certain inside portions of the cabinet being at a temperature that is far from its nominal temperature, and that is prejudicial to good conservation of foodstuffs.
It is also observed in the present state of the art that evaporators and elements situated close to evaporators in cold sales cabinets can be the subject of microbial or bacterial proliferation phenomena, with pockets of air or collections of water warmed by the action of the defrosting means presently in use providing media that encourage the development of germs, bacteria, or microbes. Since, by construction, these evaporators and their immediate vicinity are difficult to access with any kind of cleaning or decontamination means, it is unfortunately observed that these organisms can become transferred to the foodstuffs or goods conserved inside cold sales cabinets, with the vector being air which is circulated by the fans.
That said, non-published experiments performed by the authors of the present application concerning cold sales cabinets fitted with defrosting devices included in the prior art have shown that the formation of frost on the outside surfaces of evaporators does not have a totally negative effect on the performance of such cabinets: it is found that initially the appearance of a thin film of frost on the outside surface of an evaporator has the effect of increasing its real heat exchange area and thus of increasing heat exchange efficiency to a significant extent; this applies in particular when the layer of frost covering the outside surfaces of the evaporator is of a thickness that does not exceed 1 millimeter (mm). After a few minutes of operation, this positive effect is overtaken by the negative effect of the insulation caused by depositing a layer of frost and/or ice having a thickness of several millimeters; thereafter, this layer of frost and/or ice creates an obstruction, and then a complete blockage between the fins of the evaporator, which ends up by preventing all air circulation and thus preventing any heat exchange.
The invention proposes means for taking advantage of the positive effects of the appearance of frost on the surface of the evaporator and for eliminating the negative effects of said phenomenon.
More generally, the invention proposes making cold sales cabinets that mitigate all of the drawbacks described above.
An object of the invention is to provide a cold sales cabinet capable of ensuring that all of the foodstuffs it contains has a temperature that is constant in time and uniform in space.
Another object of the invention is to propose a cold sales cabinet having better energy efficiency, i.e. consuming less energy for a given level of performance.
An additional object of the invention is to make it possible to provide a cold sales cabinet of a cost price that is significantly reduced, which result is obtained by optimizing elements such as the evaporator and the fans which can operate in regular manner for up to 100% of the time, and as a result can be smaller in size than those presently used in cabinets seeking to provide performance at the same level as that provided by a cold sales cabinet of the invention.
Another additional object of the invention is to propose a cold sales cabinet having means that are of low cost and effective for eliminating any proliferation of bacteria, germs, or microbes on the evaporator and in its immediate environment, and consequently avoiding any risk of contaminating foodstuffs or goods conserved inside the cold sales cabinet.
It is known that defrosting can be performed, i.e. molecules of water in solid form can be melted to form molecules of water in liquid form, by using energy which is dissipated in the form of microwaves. For example, document GB-2 278 668 discloses a refrigerator in which the evaporator is defrosted by microwave type radiation. The evaporator and the microwave source are placed in a compartment of the refrigerator which is separated from the food by a screen which prevents the microwaves from reaching the food. The water which results from melting the frost formed on the evaporator is collected in a trough placed in the compartment.
That is the closest document although it does not relate to a cold cabinet of the type of the invention since it does not have means for circulating a flow of air. In the present invention, air circulation is very important or even essential in that it is circulating air which conveys low temperature and causes accelerated formation of frost on the evaporator.
The present invention seeks to provide a cold cabinet with forced air circulation in which the defrosting of the evaporator by microwaves gives rise neither to a rise in the temperature of the air curtain nor to a large amount of energy being consumed.
To reduce energy consumption, the present invention provides means for continuously removing water from the compartment containing microwaves. By removing the water, the quantity of energy required for defrosting purposes is reduced, since the microwaves no longer serve to heat that water and are therefore constrained to cause the frost on the evaporator to melt directly. Microwaves have a tendency to heat liquid water first and to heat solid water only subsequently. By removing the liquid water from the compartment or enclosure as it is formed, the microwaves do not have the chance of dissipating therein, and as a consequence there is a saving in radiation and thus in energy, giving rise to operation that is less expensive and faster.
If the water is not removed immediately as it forms, microwave defrosting means are found to be practically useless in terms of melting the frost that forms on the fins.
In another embodiment, the removal means consist in the circulation means. The forced air flow takes away a fraction of the liquid water present on the evaporator, removing it from the enclosure by transporting it in the air.
In a variant or in combination, the removal means comprise at least one orifice formed in the bottom wall of the enclosure. The water flows along the fins of the evaporator and falls under gravity. It is then collected in a metal receptacle and removed to outside the enclosure. Water preferably passes through the bottom wall of the enclosure subjected to the radiation via one or more orifices, a grid, or a perforated sheath, with the open section being selected as a function of the nominal frequency of the generator so as to constitute a wave trap. This passage can be accelerated by slopes converging on the evacuation orifices, where such slopes are conferred on said bottom wall by construction.
The evaporator, or at least its active portion, is contained in a microwave-proof enclosure so that the microwaves are reflected on the walls of said enclosure and release their energy firstly to the ice or frost that they cause to melt. A waveguide, preferably fitted with deflectors, serves to direct the waves onto the fins of the evaporator. It is also possible to use wave stirring means for directing or distributing the waves into preferred zones or directions. In a preferred embodiment, at least two of the walls are made in the form of perforated sheets of grids having openings of dimensions that are large enough to allow a transverse flow of air to pass through the enclosure and small enough to prevent microwave radiation escaping out from the enclosure. In an alternative embodiment of cabinets of the invention, removable partitions are installed which can be solid or partially perforated, said partitions being automatically retracted or folded away during the short periods in which the microwave generator(s) is/are in operation.
In the preferred embodiment, it will be understood that it is appropriate to make the waveguides in such a manner that the waves are directed exclusively or at least preferentially towards the evaporator, or indeed towards the zone of said evaporator which is the most subject to frosting and icing phenomena, i.e. the zone where the forced air comes into contact with said element. It is also possible to use surface waveguides placed on the outside surfaces of all or some of the fins of the evaporator. These surface waveguides are coupled to the microwave generator and made of a dielectric material whose dielectric constant is close to that of frost and whose thermal conductivity is close to that of copper; these two characteristics are advantageous: the first makes it possible to obtain good propagation of waves between the surface waveguides and the layer of frost while the second makes it possible to ensure that the surface waveguides do not act as insulators reducing the heat exchange efficiency between the evaporator and the flow of air. To obtain both of these characteristics simultaneously in spite of them being, a priori, contradictory, the surface waveguides are made of a material belonging to the family of polymers or resins doped by including particles of non-magnetic metal.
In any event, the spacing between the fins constituting the heat exchange surface of the evaporator is selected in such a manner that said spacing optimizes the passage of microwaves between two adjacent fins, i.e. the spacing should be greater than 5 mm, and in such a manner that said spacing makes it possible to obtain a large heat exchange area between the evaporator and the air, i.e. a spacing of less than 10 mm. In preferred manner, the evaporator fitted to a cold sales cabinet of the invention is thus provided with fins at a spacing lying in the range 5 mm to 10 mm.
The evaporator can be provided with a plurality of long fins projecting significantly beyond the alignment constituted by the ends of standard fins. Under such circumstances, the spacing between two long fins should be selected so that said spacing enables good microwave penetration between a long fin and its neighbors of the same category (i.e. more than 5 mm), while the spacing between standard fins is selected in such a manner that said spacing (selected to be less than 5 mm) is not compatible or is poorly compatible with microwaves penetrating into the gaps between the standard fins.


One embodiment of the present invention sets forth a method for generating work to be processed by a graphics pipeline residing within a graphics processor. The method includes the steps of receiving an indication that a first graphics workload is to be submitted to a command queue associated with the graphics processor, allocating a first portion of shader accessible memory for one or more units of state information that are necessary for processing the first graphics workload, populating the first portion of shader accessible memory with the one or more units of state information, and transmitting to the command queue of the graphics processor the one or more units of state information stored within the first portion of shader accessible memory, wherein the first graphics workload is processed within the graphics pipeline based on the one or more units of state information.

1. Field of the Invention
The present invention relates generally to generating work for a graphics processing unit (GPU) and, more specifically, to GPU work creation and stateless graphics in OpenGL.
2. Description of the Related Art
In a typical processing environment, and especially in a graphics processing environment, there is a large amount of state information that is transmitted by an application to facilitate the processing of input data in a processing pipeline. The state information is transmitted by the application executing on a central processing unit (CPU) to an external processing unit, such as a graphics processing unit (GPU), via a driver.
Existing graphics application program interfaces (APIs) have an extremely limited capacity for creating work from within the GPU. Some APIs provide a "draw indirect" functionality, where the parameters to a DrawElements or DrawArrays call (primitive type, vertex count, and indices used to address data in a vertex buffer) are taken from a buffer in GPU memory rather than being specified on the CPU. This allows those parameters to be written by the GPU, and then consumed by the GPU without being read back to the CPU. However, such a mechanism still requires that the application code running on the CPU know ahead of time that the work is going to be generated, where the corresponding parameters need to be written, and in what order various work must be executed. In addition, the CPU thread is responsible for setting up the state required to process each GPU-generated draw command as well as submitting the work. Therefore, such a mechanism does not alleviate the dependency on the CPU to create workloads or portions thereof that are to be processed on the GPU.
As the foregoing illustrates, what is needed in the art is a mechanism for effectively generating graphics workloads that are to be processed by the GPU from within the GPU.

GPU work creation and stateless graphics in OPENGL


A control circuit, a testing apparatus and a method for testing a liquid crystal display panel are provided. The control circuit includes a current sensor and a discharge signal generation circuit. The current sensor is configured to detect a change in an input current of the liquid crystal display panel to generate an indication signal, the indication signal being indicative of switching of image frames displayed by the liquid crystal display panel. The discharge signal generation circuit is configured to receive the indication signal from the current sensor, and the discharge signal generation circuit generates a discharge signal in response to receiving the indication signal, so that a liquid crystal capacitor including the common electrode and the pixel electrode in the liquid crystal display panel is discharged. Hence, the quality of images displayed by the liquid crystal display panel can be improved and the product yield can be increased.

With the advancement of technology and the improvement of people's living standards, there is an increasing demand for image display quality of electronic display devices. For example, higher resolution or refresh rate is always expected. Since the electron mobility of an oxide is much higher than that of amorphous silicon, oxide semiconductor transistors are widely used in the existing display devices.
Before leaving factory, a manufactured display panel generally needs to go through a testing process. For example, a lighting test is performed to display panels to eliminate unqualified products. However, in practice, for those display panels that have been tested and considered to be qualified products, poor display quality may still appear. For example, phenomena such as flickers, black and white spots (mura), and the like may occur on the screen when an image is being displayed.

Control circuit, testing apparatus and method for liquid crystal display panel

HEFEI XINSHENG OPTOELECTRONICS TECHNOLOGY CO., LTD.


A fishing tool is provided to enable retrieval of fish from a mineral extraction system. The fishing tool includes a frustoconical member, an outer tubular member, and an inner tubular member. The inner tubular member includes a plurality of receptacles configured to receive a plurality of jaws. Each of the jaws may include teeth on an inward facing surface of the jaw. The outer tubular member may be hydraulically actuated to cause the jaws to move radially inward and engage the fish, enabling removal of the tool and the fish. Systems and methods that include the fishing tool are also provided.

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
As will be appreciated, oil and natural gas have a profound effect on modern economies and societies. Indeed, devices and systems that depend on oil and natural gas are ubiquitous. For instance, oil and natural gas are used for fuel in a wide variety of vehicles, such as cars, airplanes, boats, and the like. Further, oil and natural gas are frequently used to heat homes during winter, to generate electricity, and to manufacture an astonishing array of everyday products.
In order to meet the demand for such natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that control drilling and/or extraction operations.
To extract the resources from a well, a drilling riser may extend from the well to a rig. For example, in a subsea well, the drilling riser may extend from the seafloor up to a rig on the surface of the sea. A typical drilling riser may include a flanged assembly formed from steel, and the drilling riser may perform multiple functions. In addition to transporting drilling fluid into the well, the riser may provide pipes to allow drilling fluids, mud, and cuttings to flow up from the well. A drill pipe may be disposed inside the riser and connected to a drillbit or other tool at the end of the well. The riser may be coupled to a blowout preventer (BOP) that can seal off the well in certain situations.
During the drilling operation, operators may lose control of the well if unexpected or excess pressure occurs. Additionally, other events, such as weather, may cause operators to seal off the well in an emergency. During such events, the BOP may seal off the well, such as through the activation of rams in the BOP. These rams may bend, cut, shear, or otherwise deform the drill pipe or other components in the wellhead. The drill pipe, tools, or other equipment left in the well are referred to as "fish." Retrieval of the fish may be challenging, time-consuming, and expensive.


A graph converter converts functionally descriptive information expressing a combination circuit into a graph expression having only NOR and inversion circuits. A multiple input NOR converter detects from the above graph expression a circuit element having a NOR circuit and an inversion circuit alternately connected in series and converts the circuit element to a graph expression where a multiple input NOR circuit replaces the circuit element. A cell mapper detects from the above graph expression a circuit element having NOR circuits connected together in series, maps the circuit element to gate cells with or without a composite cell, and outputs the mapping result with the least number of gates as the mapping output for the circuit element. A circuit element having a NOR circuit and an inversion circuit alternately connected in series is substituted by a unique multiple input NOR circuit. A circuit element mapped to a composite cell is efficiently determined just by detecting a circuit element where "nor" circuits are connected together in series. It is possible to replace NOR circuits by NAND circuits.

1. Field of the Invention
This invention relates to a technology mapping apparatus for a CMOS-LSI combination circuit configured by a logic circuit automatic synthesis technology.
2. Description of the Related Art
Automatically synthesizing a CMOS-LSI combination circuit requires a technology which not only reduces the number of gates but also enables the respective circuit elements in a combination circuit to be mapped to actually realizable gate cells (or simply cells below). This technology is referred to as technology mapping.
Technology mapping maps, through appropriate transformation, the respective circuit elements of a combination circuit to a plurality of actually realizable cells prestored in a cell library.
The conventional art of technology mapping is as follows: First, a combination circuit is expressed by a graph of a NAND circuit (NAND) or NOR circuit having two (2) input terminals and an inverter (INV). This is the case for all patterns stored in the cell library. By searching the respective circuit elements in a combination circuit for matching graphs in the cell library, the mapping technology causes the circuit elements to be mapped to the matched cell.
However, since the above prior art needs to have a cell library which stores the graphs corresponding to all possible patterns formed as respective circuit elements, it is disadvantageous because the cell library must store a huge volume of data and the matching step requires a huge processing volume.
When a graph matches with a NAND cell having five (5) input terminals, for instance, the graph also matches with NAND of cells having four (4), three (3) and two (2) input terminals. Therefore, when a cell has mores than two (2) input terminals, the same path in the cell library is searched multiple times. This causes a problem in that the matching process becomes very inefficient.
Furthermore, since the cell library has plural kinds of cells which match the respective circuit elements, the combination circuit having the minimum number of gates must be found among all possible combinations of cells to which respective circuit elements are mapped. Hence, a problem arises in that the processing volume becomes enormously large.

Technology mapping apparatus for a combination circuit for use in automatically synthesizing an LSI logic circuit


Nickel ion contained in a ferric chloride waste liquid is recovered as metallic nickel by the following method. Firstly, the ferric chloride waste liquid is added with metallic iron and then heated and stirred to precipitate the metallic nickel. Thereafter the sludge containing this metallic nickel precipitate and the suspension are separated. Then, after the ferric chloride waste liquid is poured into the sludge and then heated and stirred so as to dissolve an iron constituent of the sludge and react it with the ferric chloride waste liquid, the suspension and the sludge are separated. After that, the sludge after the concentration process is taken out.

1. Field of the Invention
The present invention relates to a method for effectively recovering nickel as a useful metal from a sludge by increasing the proportion of a nickel constituent contained in the sludge at the time of precipitating as the sludge the nickel dissolved in the ferric chloride waste liquid containing nickel and other heavy metals such as the etching waste liquid during reproduction of the ferric chloride waste liquid.
Generally, the ferric chloride waste liquid is used broadly as an etching liquid for precisely processing a metal plate made of stainless steel, nickel alloy and so on. As the etching liquid is used repeatedly for the corrosive treatment, it is apt to accumulate heavy metal ions such as nickel ion and the like therein as well as tervalent ions are reduced to bivalent ones. Meantime the etching liquid loses its corrosive effect and finally becomes the waste liquid. Since many pollution-related problems arise when this waste liquid is dumpted much after having been merely neutralized by alkali, it is requested to apply the reproductive and recycle process to the waste liquid.
2. Description of the Prior Art
As a method for reproducing the aforementioned waste liquid it might be proposed to blow the chlorine gas into the waste liquid directly so as to oxidize the bivalent iron ions to the tervalent ones. Practically, however, a corrosive effect of the reproduced process liquid doesn't recover sufficiently by this processing method. The reason is assumed that the heavy metal ions such as the nickel ion dissolved from the metallic plate into the waste liquid by the etching process tend to obstruct the oxidizing reaction.
Then, such a reproduction processing method for recovering the corrosive effect sufficiently is proposed by the Japanese Patent Publication No. Sho 61-44814. According to this reproduction processing method, lumps of metallic iron are added to the waste liquid and then heated and stirred so as to precipitate heavy metals. After the precipitated metals have been removed as a sludge, the chlorine gas is blown into the waste liquid so as to reproduce the liquid to the ferric chloride liquid.
But, the above-mentioned reproduction processing method requires an excessive addition of the metallic iron for precipitating the heavy metals. The unreacted portion of this excessive metallic iron is apt to be contained much in the sludge produced. That is, since most of the metallic constituents in the sludge is occupied by the iron constituent, the proportion of useful metals such as the nickel contained therein is not very high. For example, in the case that the reproducing process is performed by addition of the metallic iron to the ferric chloride waste liquid produced by the etching for stainless steel, the iron constituent of the metal constituents in the sludge occupies more than 90% and the nickel constituent is less than 10%. As a result, since it is impossible to effectively recover the useful metals such as the nickel from the obtained sludge, disadvantageously an economical value of the sludge is low.
On one hand, in order to reproduce the ferric chloride waste liquid effectively, formerly the inventor of the present invention proposed such a method as to increase a processing reaction speed by adding metallic copper together with the metallic iron (refer to the Japanese Patent Layed Open Publication No. Hei 2-229724). But, there are several problems associated with this method, although the processing reaction speed is increased, that the metallic copper increases the reproduction cost while similarly to the prior art, since the sludge contains the excessive unreacted metallic iron much, the proportion of such useful metals contained in the sludge is low. Further, since the sludge contains also much added metallic copper, the purity of the precipitated metallic nickel is low and the economical value of the sludge is still low.

Method for recovering metallic nickel from ferric chloride waste liquid


A method for controlling fire ants is described, which includes applying a silver-containing composition to an area infested by fire ants or threatened by an infestation. The composition is applied to the area and reduces or eliminates the colony within a period of about two to four weeks and prevents fire ant re-infestation for a period of about six months to one year.

The present teachings relate to methods for controlling insect pests.
Fire ants are known as pests across the globe and comprise almost 300 different known species of stinging ants. Most fire ant species are not a serious threat to humans and of the few species that are, most are controlled by natural forces such as parasites, predators and natural competition from other ant species. The species known as the red imported fire ant (Solenopsis invicta, also referred to as "RIFA") originated in South America and was inadvertently imported into the southern United States in 1929. Since then, in the absence of its natural predators, parasites and competitors, S. invicta has spread from coastal areas of Alabama to infest large parts of the southern U.S. Farmers and homeowners consider them a serious pest, and more recently they have spread to parts of Asia and Australia.
Fire ants feed primarily on young plants and germinating seeds and can cause significant agricultural damage, particularly to grain, fruit, nut and root crops. They occasionally eat other insects such as crickets, and may attack small animals and can kill them. They nest in soil and their large mounding nests have been linked to the decline of ground nesting birds such as the Bobwhite Quail. Although typically not a serious health threat, the sting of the fire ant can be quite painful and the discomfort is multiplied when, as often happens, the victim is attacked by multiple ants and suffers repeated stings. Sting sites are at risk of infection and scarring. Anaphylaxis is a known risk for certain individuals with heightened immunologic sensitivity to fire ant venom.
Individual mound treatment and broadcast treatment are two approaches to fire ant control using insecticides such as carbaryl, diazinon, and dursban, or an insect growth regulator. Both methods are limited primarily by the requirement that the active compound make direct and sometimes lasting contact with the colony ants and particularly the queen. Individual mound treatment is limited by the fact that the queen is sometimes too deep within the colony to be contacted by the active compound. Care must be taken not to disturb the mound prior to application of the drench. A disturbance will alert the colony and the queen may be taken deeper into the mound. In addition, application of insecticidal surface dusts or granules have a limited effect on a colony if they are not watered in. Dissolved granules must come into direct contact with the ants to have any effect. As in mound drenches, care must be taken not to disturb the colony prior to application. Some insecticides are intended as injectants. While injectants can be more effective than surface applications or mound drenches, they are also more expensive and can be dangerous if not handled properly.
Certain biological control methods have been tried. In the southern United States a species of phorid flies, a natural parasite of fire ants, have been introduced. Not all introductions have been successful, although the fly has been established successfully in some sites in every southeastern state. In Australia, fire ant colonies have been controlled with ground bait of food laced with contraceptive compounds that make the queens infertile. Some success has been obtained at the cost of instituting a necessarily highly organized, lengthy and costly national eradication campaign, including acquisition and analysis of satellite imaging data at a huge and ongoing financial cost. Moreover, broadcasting baits are limited by a slow time course of action, lack of specificity to fire ants, influence of temperature on ant retrieval of the bait, and the fact that the baits dissolve in water and become irretrievable by fire ants. A need thus remains for inexpensive, easy to use and effective methods for controlling fire ant infestations.


A light emitting diode (100 or 150) includes a diode structure containing a quantum well (120), an enhancement layer (142), and a barrier layer (144 or 148) between the enhancement layer (142) and the quantum well (120). The enhancement layer (142) supports plasmon oscillations at a frequency that couples to photons produced by combination of electrons and holes in the quantum well (120). The barrier layer serves to block diffusion between the enhancement layer (142) and the diode structure.

Light emitting diodes (LEDs) can convert electrical energy into optical energy for lighting and optical signaling. In general, LEDs are semiconductor diodes, typically containing a p-i-n junction. When an LED is forward biased, a current of electrons from the n-type material of the diode and holes from the p-type material of the diode combine. LEDs generally employ materials that create a suitable energy difference between the conduction band of electrons and the valence band of holes, so that the combination of an electron and a hole can spontaneously emit a photon. The energy difference is generally limited by the available materials but can otherwise be tuned or chosen to produce a desired frequency of light. Additionally, an LED can employ multiple layers of materials with conduction bands of different energies to create a quantum well that tends to confine electrons or holes and enhance the rate of spontaneous emissions, thereby improving energy efficiency of light production.
The spontaneous emission rate of a quantum well in an LED is not an intrinsic property of the quantum well, but instead depends on the electromagnetic environment of the quantum well. A plasmonic LED can exploit this phenomenon by positioning a quantum well close to a metal that supports the formation of surface plasmon polariton with electron-plasma oscillations extending into the quantum well. These electron-plasma oscillations or plasmons increase the electron-hole pair recombination rate within the quantum well via the Purcell effect and decrease the delay between a change in the current driving the LED and the corresponding change in the light emitted from the LED. Plasmonic LEDs can emit light with a modulation speed of about 10 GHz or faster while maintaining a radiative efficiency above about 20%, which compares well with the modulation speeds and efficiencies of VCSELs and other semiconductor lasers. International App. No. US/2008/001319, entitled "PLASMON ENHANCED LIGHT-EMITTING DIODES" describes some prior plasmonic LEDs that are fast enough for use in high data rate signaling.
One concern in manufacture of plasmonic LEDs is the materials available that are able to support surface plasmons of the proper frequencies for a plasmonic LED. Considering the limitations on the frequency of the emitted light placed by the available materials suitable for LEDs, silver and gold have been found to have surface plasmons with a desirable coupling for improving the response of an LED. Unfortunately, silver and gold, which must be close to a quantum well to provide the desired enhancement, have a tendency to migrate or diffuse in the semiconductor materials used in LEDs, and this diffusion can cause rapid degradation and shorting of the LED.
Use of the same reference symbols in different figures indicates similar or identical items.

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