A method and device for mounting a sensor to a surface that is flat in one dimension and flat or curved in a second dimension. The mounting method results in stable self-centering attachment of the sensor to the surface across a wide range of radii in the second dimension of the surface. A fixed distance and angle between the sensor components and the surface is automatically maintained despite wide changes in the radius of the surface. An attachment means is provided that is secure, repeatable, and reusable. Additionally, a means of maintaining a clear unobstructed window between the sensor and surface is provided.

1. Field of the Invention
The present invention relates generally to methods and devices for mounting a sensor securely to variably shaped surfaces. One specific embodiment of the invention relates to mounting a biomass sensor to the external surface of a biofermenter.
2. Description of Prior Art
i. Mounting Methods for Non-Invasive Sensors
Non-invasive sensors are widely used in the analysis of material properties. A great advantage of such sensors is that they allow measurements to be made without consuming, infecting, or damaging the material being analyzed. However, for such sensors, maintaining a fixed geometric relationship between the sensor and the material under test is frequently essential to maximizing the accuracy and reproducibility of the measurement. Specifically what is frequently required is to maintain a fixed distance and angle between the sensing components in the sensor, and the surface of the material or the surface of the container holding the material. A particular challenge for sensor mounting is posed when the container holding the material or the material itself is cylindrical in shape, and the radius of the cylinder may vary widely. Prior art has addressed this subject in a variety of ways.
U.S. Pat. No. RE36130—Haynes discloses a method for measuring pipe thickness using a sensor attached to a glide plate that maintains contact with the pipe. The glide plate has a curved underside that matches the shape of the outer surface of the pipe. A manual means of adapting the apparatus for different pipe diameters is provided, but only for a limited range of radii. In addition, the distance between the individual sensor components and the pipe will vary with pipe diameter unless a new glide plate is used for each new pipe diameter.
U.S. Pat. No. 6,622,561—Lam discloses a method of detecting flaws in tubes, employing a sensor mounting pad in one of several possible configurations: (1) the surface of the mounting pad is designed so that it corresponds in shape to the tube, (2) the mounting pad is fabricated from flexible material, or (3) an inflatable component is adjusted to conform the mounting pad to the shape of the tube. The disadvantage of these methods is that they are not automatically adaptable to variable radius surfaces (ie. they requires changing the mounting pad, raising or lowering shoe, or changing the bladder inflation). In addition, this method only provides a means of maintaining a fixed distance between the tube and the entire sensor, as opposed to the individual components in the sensor. As the tube radius is changed, even if a fixed distance is maintained between the tube and the nearest point on the sensor body, the distance between the individual sensor components and the pipe body may change as a result of the changing curvature of the tube.
U.S. Pat. No. 5,007,291—Walters discloses a method of mounting a sensor in close proximity to a pipe in order to inspect its quality. A proximity sensor is used in conjunction with feed-back control and a hydraulic mechanism to maintain a fixed distance between the sensor and the surface of a rotating pipe under inspection. This method has the disadvantage of being cumbersome, complex, expensive, and automatically adaptable to only a narrow range of pipe radii.
U.S. Pat. No. 4,320,659—Lynnworth discloses a system for measuring fluid impedance or liquid level through the wall of a cylindrical container. A method for mounting the sensor is described that maintains floating contact between the sensor and the external wall of the container. The sensor mount is held in place by either magnetic or adhesive means. The methods provided are not automatically adapting to varying radius containers. In addition, the magnetic attachment method provided will only work on steel containers and may be insufficiently secure in high vibration environments. Adhesive attachment is more secure and applicable to a wider array of surfaces, but is not easily removable. Adhesives typically require surface preparation and may fail under constant load. In addition, the use of adhesive would hinder rapid transfer of the sensor between containers, would limit its reusability, and may foul the surface of the vessel being probed.
U.S. Pat. No. 5,644,093—Wright discloses a sensor mounting method employing adhesive pivoting feet that are adaptable to variable radius cylindrical surfaces. In addition, a spring is provided for maintaining contact between the sensor and the mounting surface. The disadvantages associated with the use of adhesive for attachment are described above. The use of pivoting feet reduces the strength of the mounting device and increases the likelihood that the mount could flex or fail in response to force, vibration, or temperature changes. Also, the position of the sensing components within the sensor is not automatically fixed with respect to the mounting surface. Therefore, variation of the radius of curvature of the mounting surface may result in variable distances and angles of the sensor components relative to the surface.
U.S. Pat. No. 4,019,373—Freeman discloses an ultrasonic transducer for sensing flow velocity through a pipe wall. A U-shaped member is used to provide stable mounting of the transducer onto the pipe. Transducer position is adjusted axially by means of a screw thread. The disadvantage of this method is that only a narrow range of pipe radii may be accommodated. In addition, manual adjustment of transducer position is required in order to achieve a fixed distance between the transducer and pipe surface. As a result, the device is not rapidly transferable between pipes, and may be prone to user error, if the transducer position is not carefully adjusted.
U.S. Pat. No. 4,242,744—Rottmar discloses a method of fixing a sonic or ultrasonic transducer to a container for level detection. A spring is used to urge the transducer towards the container. The disadvantage of this method is that no means is provided to maintain a fixed angle between the sensor and the container. As a result, a fixed geometry between the transducer components and container may not be maintained between different placements of the transducer either on the same container or on containers of different size.
ii. Measurement of Biomass in Liquid Cultures
Liquid cultures of cells or microorganisms are frequently grown for research purposes or for commercial gain. Cells or microorganisms can be genetically modified to produce high yields of chemicals that may be difficult, expensive, or impossible to synthesize by other means. In order to prevent growth of other undesirable cells or microorganisms in the same liquid culture, it is important that the culture be grown under sterile conditions. For this reason, the growth medium is sterilized prior to inoculation with the desired cell or microorganism. In order to maintain a barrier to foreign organisms and optimize the growth of the desired cell or microorganism, liquid cultures are frequently grown under highly controlled conditions in what are referred to as fermenters or bioreactors. For research purposes, fermenter vessels are typically cylinders constructed from glass or plastic, having liquid capacities ranging from less than 1 L up to 20 L. For larger scale production, stainless steel tanks with capacities from 10 L up to thousands of liters or more are frequently used. A flat glass port is typically provided on the side of such vessels, to allow for viewing of the liquid culture. In addition to maintaining sterile conditions, fermenters may provide control over such parameters as temperature, pH, rate of stirring, and concentration of nutrients and dissolved gases.
Cells or microorganisms typically undergo several stages of growth in a fermenter. After inoculation, the initial growth rate of the cells or microorganisms may be slow, as the organism becomes accustomed to its new environment. This is frequently followed by a rapid growth phase where the biomass increases nearly exponentially. This growth period is sometimes referred to as the "log phase" due to the fact that the change in the logarithm of biomass is nearly linear with time. Eventually, as the nutrient supply relative to the biomass diminishes, the growth will slow. In order to achieve maximum biomass, the conditions in the fermenter need to be changed during the different phases of growth. Ideally a feedback mechanism would link the measured growth of the cells or microorganisms to the conditions in the fermenter. Frequently, a physical or chemical stimulus is used to induce production of a desired chemical by the cells or microorganisms. The timing of this induction relative to the growth cycle of the cells or microorganisms is often critical in order to achieve maximum chemical yield. Unfortunately, methods of continuously and reliably measuring the growth of cells or microorganisms in liquid cultures are not widely available.
The most commonly used method of measuring the biomass in liquid cultures is by extracting a portion of the liquid and measuring its optical density in a spectrophotometer. This method has several disadvantages: (1) each time liquid is withdrawn, there is a risk that the culture will be contaminated, (2) the method is not continuous, and (3) the method is labor intensive, requiring frequent extraction and precise volumetric dilution of the extracted liquid when high cell concentrations are measured. Commercial devices are available (eg. Wedgewood Technology, Incorporated, Model 650 "Absorbance Monitor") that offer continuous measurement of optical density using a probe that is immersed in the liquid culture. Unfortunately, such devices are prone to drift, particularly due to growth of cells or microorganisms on the sensor itself.
Non-invasive methods of biomass monitoring have also been described in prior art. U.S. Pat. Nos. 5,483,080—Tam and 6,573,991—Debreczeny both describe non-invasive reflectance sensors for measuring biomass in liquid cultures through the wall of a fermenter. By these methods, biomass is measured free from the risk of contaminating the culture. However, sensor mounting methods are not provided that automatically compensate for changes in the shape and size of the fermenter. Due to the wide variety of sizes and shapes of research and production-scale fermenters, external mounting of sensors to the fermenter presents a particular challenge.


A base support for supporting a post or other upright in a generally upright position includes an elongated base member having a wider portion intermediate its length containing a mounting hole for receipt of an end portion of the post or other upright. A carrying handle may be provided on a side wall of the base member adjacent one end of the wider intermediate portion.

There are many different known types of base supports used to support posts or other uprights used for example to support portable traffic barricades, signs, fencing and other devices in a generally upright position. However, there is a continuing need for such a base support that includes both strength and flexibility in a cost effective design. Also there is a continuing need for such a base support that is relatively easy to set up and take down, and allows the post or other upright to break away from the base support if the traffic barricade, sign, fencing or other device supported thereby is impacted for example by a vehicle, thereby minimizing possible damage to the vehicle.


A deposition process for coating a substrate with an ultrasonically generated aerosol spray, is described. The resultant droplets are much smaller in size than those produced by conventional processes, thereby providing the present coating having an increased surface area. When the coated substrate is an electrode in a capacitor, a greater surface area results in an increased electrode capacitance.

1. Field of the Invention
The present invention generally relates to a deposition process for coating a substrate with an ultrasonically generated aerosol spray. More particularly, the present invention relates to a metallic foil provided with an ultrasonically generated aerosol spray. Still more particularly, the present invention provides a porous, high surface area metal oxide, metal nitride, metal carbon nitride or metal carbide coating on a conductive foil for use in a capacitor and the like.
2. Prior Art
In redox active structures, energy storage occurs during a change in the oxidation state of the metal when an ionic species from a conducting electrolyte, for example a proton, reacts with the surface or bulk of the oxide. This chemisorption is accompanied by the simultaneous incorporation of an electron into the oxide. The surface (or bulk) interaction between the electrode and electrolyte gives rise to capacitance in the hundreds of .mu.F/sq.cm. It follows that a electrode with high specific surface area will store a significant amount of energy and will have a large specific capacitance. These electrodes are then appropriate when used as the anode and/or cathode in electrochemical capacitors or as cathodes in electrolytic capacitors, which require high specific capacitances.
Whether an anode or a cathode in an electrochemical capacitor or the cathode in an electrolytic capcitator, a capacitor electrode generally includes a substrate of a conductive metal such as titanium or tantalum provided with a semiconductive or pseudocapacitive oxide coating, nitride coating, carbon nitride coating, or carbide coating. In the case of a ruthenium oxide cathode, the coating is formed on the substrate by dissolving a ruthenium oxide precursor such as ruthenium chloride or ruthenium nitrosyl nitrate in a solvent and contacting the solution to the substrate. The thusly coated substrate is then heated to a temperature sufficient to convert the deposited precursor to a highly porous, high surface area pseudocapacitive film of ruthenium oxide provided on the substrate.
The prior art describes various methods of contacting the substrate with the semiconductive or pseudocapacitive solution, or precursor thereof. Commonly used techniques include dipping and pressurized air atomization spraying of the pseudocapacitive material onto the substrate. Capacitance values for electrodes made by dipping, pressurized air atomization spraying and sputtering are lower in specific capacitance. Sol-gel deposition is another conventional method of coating the substrate. It is exceptionally difficult to accurately control the coating morphology due to the controllability and repeatability of the various prior art techniques, which directly impacts capacitance.
Therefore, while electrochemical capacitors provide much higher energy storage densities than conventional capacitors, there is a need to further increase the energy storage capacity of such devices. One way of accomplishing this is to provide electrodes which can be manufactured with repeatable controllable morphology according to the present invention, in turn benefiting repeatable increased effective surface areas.

Ultrasonically coated substrate for use in a capacitor


An apparatus for measuring and storing a tree characteristic that preferably is tree diameter and other data related to location, variety and grade of a tree being measured. The apparatus has a handle, a wand extending therefrom, and a measurement head carried by the wand for measuring diameter. The wand has a control handle connected by a cable to a movable caliper jaw carried by the head to measure a diameter of a tree between the movable jaw and another jaw. A vernier having measurement locator slots and a home position slot is carried by the cable and communicates with slot sensors that send signals to an on-board computer to determine direction and distance of jaw movement for enabling the distance between the jaws to be determined. Two optoisolators and the computer comprise a jaw motion and direction detecting quadrature detector. A third optoisolator detects when the movable jaw is in its home position. The computer includes a microcontroller, a memory for storing tree data, a port for transferring stored data from memory to a PC, and inputs for selecting and storing data. A memory cartridge can be used to store tree data. Software running on the PC enables data to be downloaded, sorted, stored, displayed or printed. The software is also used to configure cartridges by downloading at least a portion of a master list of locations and varieties to a cartridge being configured that can later be selected in the field during apparatus operation.

In many businesses related to the forestry and nursery industries, the measurement and recording of certain tree characteristic information, such as tree diameter, location, quality or grade, type of tree and the like, are determined and recorded for the purpose of making an inventory. For the forestry industry, inventorying large stands of trees can help determine or approximate the future value of the lumber that will be harvested when the trees are cut down. Likewise, in the nursery industry, inventorying nursery tree stock is also important for determining the value of the trees that will be sold during the upcoming sales season. Inventorying a nurseries' stock of trees is also important so that the nursery knows how many trees of a particular variety, grade and size it can sell during the sales season.
In the past, inventorying trees has largely been performed manually using a caliper-like device to measure tree diameter and writing down the information in a paper inventory log. Typically, for the nursery industry, inventory information for each tree includes the location of the tree, the type or variety of the tree, the grade or quality of the tree, as well as the diameter of the tree. Unfortunately, manual recording of this information is slow and labor intensive, especially when it is considered that the manually recorded information is usually later manually transcribed or rerecorded into a computer.
In an attempt to address at least some of these challenges as they are presented in the lumber industry, Luikko, U.S. Pat. No. 5,022,162, discloses an electronic caliper having a display and means for inputting alphanumeric information into a record that can be stored in a computer memory. To determine the diameter of a log, a moveable jaw is slid by an operator of the caliper toward a fixed jaw of the caliper until the two jaws bear against the log. When performing this measurement, the distance between the two jaws is shown in the display. Thereafter, a switch is pressed to enter the measurement shown in the display of the caliper into memory. To selectively input other numbers, and even letters, when prompted, the movable jaw of the caliper is moved along an arm of the caliper by the operator until the jaw indicates the desired number or letter and thereafter the switch is pressed to enter the selection into memory.
Unfortunately, this method of data entry is rather slow and tedious, requiring the operator to spend a considerable amount of time to manually slide the jaw along the arm to take a measurement before entering it into memory. Additionally, the operator must spend valuable time to directly manipulate the moveable jaw to select a desired number or letter before entering it into memory. Moreover, a person using such a caliper must undesirably bend down or kneel, if measuring the diameter of the trunk of a standing tree close to the base or bottom of the tree being measured, further wasting time and quite possibly causing discomfort to the operator if a large number of trees are being measured. Although the apparatus disclosed in the Luikko patent may be better suited for inventorying cut logs that have been horizontally stacked, its poor ergonomics make it poorly suited for inventorying vertically standing trees and, more particularly, for inventorying large groups of standing trees. Finally, as a result of these drawbacks, the apparatus disclosed in the Luikko patent is simply impractical for use in quickly inventorying large stands of trees having, for example, two hundred or more trees.

Apparatus for measuring and recording a tree characteristic


A process and system are provided for recognizing the movement of a motor vehicle as well as a process for using an acceleration sensor in a device for blocking the starting of a motor vehicle. Reliable information is obtained on whether or not the motor vehicle was moved. In the process for recognizing the movement of a motor vehicle, the accelerating forces acting on the motor vehicle are measured for this purpose as time-dependent functions and are subjected to a discrete Fourier analysis. If the majority of the frequencies determined is below a preset limit frequency, e.g., 0.3 Hz, movement of the motor vehicle is assumed, and an irrelevant vibration is otherwise assumed. An acceleration sensor is used in a device for blocking the starting of a motor vehicle and/or to demonstrate an inadmissible circumventing of the blocking.

Interlock systems, which are to prevent the unauthorized starting of the motor vehicle, are installed in motor vehicles. Starting is unauthorized, e.g., if a motor vehicle is stolen or the user of the motor vehicle is under the influence of alcohol. In the latter case, the starter in a motor vehicle with an interlock system installed can be actuated only when the user had previously undergone a breath alcohol test and the value measured in the test is below a certain limit value. Since such a breath alcohol test is not intended to be a breath alcohol test performed by the police within the framework of a traffic check, attempts at deception cannot be ruled out, in which the breath alcohol test is circumvented or the motor vehicle is pushed or started by another person, even though the value measured in the breath alcohol test is above the limit value. Such attempts of deception represent a violation of the legal conditions, have far-reaching consequences for the person involved and must therefore be reliably identified or ruled out.
Prior-art interlock systems monitor, e.g., the vehicle system voltage in the motor vehicle, doing so even when the motor vehicle is stopped and the ignition is not turned on. However, a sample is requested for the breath alcohol test only after the ignition had been turned on. The drop in the vehicle system voltage during the start-up of the motor vehicle is used here as a criterion of whether or not a start has taken place. If a drop in the vehicle system voltage is indeed registered when the breath alcohol test has not been passed, an entry is made in the memory of the interlock system, which is read, e.g., by an inspection station at monthly intervals. However, the detection of the vehicle system voltage is not a reliable criterion for the question of whether the motor vehicle was started or not, because a drop in the vehicle system voltage may also be caused by turning on an air conditioner, a radio, windshield wipers or a fan in the motor vehicle.
Another possibility of demonstrating the unauthorized starting of a motor vehicle is described in U.S. Ser. No. 2002/0039951 A1. An acceleration sensor with a control means for the ignition and the fuel supply is used there on a motorcycle. The acceleration sensor also takes into account the gravitational acceleration and, in a preferred embodiment, it is able to measure the accelerations in two directions directed at right angles to one another. Signal noise and vibrations, which shall be left out of consideration, are eliminated by a downstream filter.

Process for recognizing the movement of a motor vehicle


A rotating spindle attachment device particularly useful in electrical discharge machining for detachably mounting an electrode to the ram of an electrical discharge machine (EDM). The unit incorporates an electric drive motor, threaded drive shaft, detachable electrode chuck, and water-tight seal(s) for use in mounting, sealing, and rotating a consumable electrode about its vertical axis relative to the workpiece.

1. Field of the Invention
This invention relates to the area of machine tools and more particularly relates to a rotating spindle attachment device for detachably mounting an electrode on an electrical discharge machine (EDM). The invention includes a detachable spindle assembly incorporating an electric drive motor, threaded drive shaft, detachable electrode chuck, and water-tight seal(S) for use in mounting, rotating, and sealing a consumable electrode about its vertical axis relative to the workpiece.
2. Description of the Related Art
The present invention relates to a new and novel attachment device that can be detachably mounted for use with an electrical discharge machine (EDM). EDM machining is a relatively recent technological innovation and greatly expedites the forming of apertures, cavities or holes in a metal workpiece particularly where relatively small size apertures, cavities or holes are required and with relatively close tolerances.
In the present invention the electrode, being consumable, is detachably mounted on the EDM machine for rotational movement about its axis so as to remove metal from the workpiece, by fusion, so as to form apertures or holes in the workpiece as one would accomplish by conventional drilling or milling machines. Conventional EDM machines typically supply the means (via industrial standard fluid pumps and connectors) to communicate and deliver dielectric oil to the electrode and workpiece as it is desirable, during EDM machining, to effectively flush particles therefrom.
The ability to rotate the electrode makes the flushing operation easier because the rotational movement of the electrode mechanically aids in the exchange of dielectric fluid between the electrode and workpiece. In addition, a rotating electrode is engaged with the workpiece on all sides which causes the entire surface of the electrode to be used thus permitting a greater electrode surface area to be involved in the machining process which allows the machining current to be increased to improve the metal removal rate.
Also, electrode rotation greatly reduces side wall taper of the workpiece. Heretofore, known attachment devices for rotably mounting and sealing the electrode have not been entirely satisfactory especially from a cost effective point of view. In addition, such prior rotational mounting devices have not been satisfactory in enabling the operator to quickly and easily install the device to an EDM machine. Also, such prior rotational mounting devices have not been satisfactory in enabling the operator to quickly and easily replace and seal a plurality of electrode diameters while at the same time maintaining a high degree of machining efficiency and accuracy.

Attachment device for electrical discharge machine


A method for controlling an air sampling pump includes establishing from empirical measurement a family of sets of data relating speed of the pump to the flow rate of air through the pump as a function of pressure drop of the air at the pump inlet and storing the data in an electronic memory. The pump is then operated at a selected speed corresponding to a desired air flow rate and selected inlet pressure drop. The actual pressure drop is measured and a pair of sets of pressure drop values are identified in the stored data, which values bracket the actual measured pressure drop. The desired air flow rate and corresponding pump RPM value for each of the identified pair of sets of differential pressure values are located and extrapolation is used to locate a new value of RPM for delivering the desired air flow rate at the actual measured value of pressure drop. The pump is then operated at the new RPM value.

This invention relates to battery powered air sampling pump systems and, more particularly, to a pump system for maintaining constant air flow rate.
U.S. Pat. No. 5,107,713 (the "'713 patent"), assigned to the assignee of the present invention, describes a portable air sampling pump system of the type generally carried or worn by a person in order to collect environmental air samples for determining air quality. The pump system of the '713 patent comprises an air sampling pump having a central processing unit (CPU) for developing pulse width modulation (PWM) control signals for application to a PWM motor driver which is connected to supply electric power to a DC electric motor. The motor is coupled in driving relationship to a diaphragm type air pump and a revolution per minute (RPM) counter is coupled to the motor/pump assembly for providing RPM signals representative of pump speed to the CPU. The CPU includes memory operably associated with it for storing data indicative of predetermined relationships between RPM, PWM and air flow. The CPU is responsive to a commanded air flow signal for generating a corresponding PWM signal for energizing the motor at a preselected RPM. The relationship between motor RPM and air flow rate is obtained by a combination of empirical measurement and interpolation. In one form, the pump is initially energized at a preselected PWM value and the pump flow rate and RPM corresponding to that PWM value are recorded. The pump is then energized at another PWM value and the pump flow rate and RPM corresponding to that value are also recorded. These two values enable development of a characteristic curve for the pump. Tables of PWM values relating RPM and flow rate to PWM are computed from the two measured values. When a desired flow rate is set in the CPU, the CPU generates a PWM signal to energize the pump at an RPM corresponding to the desired flow rate. Thereafter, the RPM of the pump is monitored and the PWM value periodically adjusted to maintain the RPM at the selected value.
While the system described in the '713 provides relatively accurate control of air flow rate, it is not as precisely accurate as is desirable when measurement of some air borne contaminants are being monitored at concentrations measured in parts per million. The '713 patent system uses the assumption that air flow rate is directly approximate to pump RPM. However, a more accurate measurement is needed to accommodate variations in the system such as may be caused by clogging of an input filter designed to remove dust or other debris from the air being sampled.

Buck air sampling pump flow control algorithm


A battery operated extension cord that includes a housing, a rechargeable battery pack, a pair of 125-volt alternating current receptacles, a power inverter to convert the voltage direct current from the battery to the required alternating current, a charger, and a plug connected to the charger to allow the charger to be plugged into an existing wall plug unit in order to charge the present invention. The housing is located in a hinged-carrying case, which includes a separate pocket for the battery housing and a cylinder around which the extension cord could be wound.

The present invention concerns that of a new and improved battery operated extension cord that includes a housing, a rechargeable battery pack, a pair of 125-volt alternating current receptacles, a power inverter to convert the voltage direct current from the battery to the required alternating current, a charger, and a plug connected to the charger to allow the charger to be plugged into an existing wall plug unit in order to charge the present invention.


A symmetrical printed meander dipole antenna includes a dielectric board including a ground plane; a first antenna trace line disposed on a first portion of the dielectric board and in electrical contact with the dielectric board, the first antenna trace line including a plurality of first vertical meandered traces; a second antenna trace line disposed on a second portion of the dielectric board and in electrical contact with the dielectric board, the second antenna trace line including a plurality second vertical meandered traces, wherein the first and second plurality of vertical meandered traces are symmetrical to each other; and an inductor in contact with the first and second antenna trace lines for tuning the impedance of the symmetrical printed meander dipole antenna.

In recent years, the wireless communication market has expanded greatly. Wireless devices, such as remote control engine start systems, remote keyless entry ("RKE") systems, and automatic tolling systems are now considered "classical" devices for short range vehicle wireless communication. Such control and security devices commonly operate in the 315 MHz frequency in the United States, Canada, and Japan. In these systems, the antenna is a key element in determining system size and performance. Examples of external and internal antennas that are in current production are known. As a rule, internal antennas are printed on dielectric boards together with electronic components of RKE systems, for example. The integration of radio frequency ("RF") and digital electronic components with receiving antennas reduces the number of wires and connectors, thus reducing system costs. Nevertheless, such designs have a significant disadvantage, namely parasitic emissions from electronic components (oscillators) located on the circuit board that can markedly reduce the communication range.
An external dipole antenna does not have such a disadvantage because it is isolated from the elements of the control electronics. Unfortunately, such antennas with lengths of about 30 cm are large and inconvenient for interior vehicle applications. The "pigtail" coaxial antenna described in U.S. Pat. No. 6,937,197 avoids some of the problems seen in external dipoles, and thus may be more convenient for automotive interior applications. The pigtail is made by simply stripping off the outer conductor of the coax to extend the inner conductor to a length equal to approximately a quarter-wavelength; the cable becomes a part of the antenna. One problem associated with pigtail antennas is that in automotive applications pigtail antennas are positioned very close to the car body as a part of a cable harness. Because of the metal shadows from the car body, the pigtail has very small gain; the small gain in turn causes reduced communication range. Therefore, in applications where communication range is a critical factor, pigtail antennas are not acceptable for automotive antenna applications.
Referring to FIG. 1, a conventional asymmetrical meander antenna 50 is shown, which tends to have a significant current flow in the outer conductor of the RF cable 54 that connects the asymmetrical meander antenna 50 with a control module, such as remote keyless entry (RKE") module 58. Asymmetrical meander antenna 50 includes asymmetrical trace lines 52 that are printed on a printed circuit board (PCB"). Essentially, the RF cable 54 becomes part of the asymmetrical meander antenna 50 and provides for extended signal range. A drawback of such asymmetry is that the cable location influences the communication range of the RKE system. Modern vehicles have many different electronic devices, including heaters, air conditioning modules with automatic temperature control, audio amplifier systems, heated seat modules, power control modules, and sunroof modules, for example. Parasitic emissions from these electronic devices near the routing path of the external antenna's RF cable can reduce the communication range of the asymmetric RKE system. In fact, electromagnetic compatibility ("EMC") measurements show that such interference can exceed the noise floor level of the RKE system by more than 20 dB.
In one example, a nominal communication range for asymmetrical RKE systems is approximately 100 m in the absence of parasitic emissions. Experimental measurements show that the noise received by the RF cable can exceed the noise floor of the RKE by 20 dB. Such noise level reduces the communication range of the RKE systems to 20 m or less. Generally, the effect of parasitic components on a cable can be minimized by using a special passive electronic device, such as a balun, for balancing impedances, between the antenna and RF circuit. Nevertheless, such a printed-on-circuit-board balun has a linear size equal to a quarter of the wavelength, and therefore is generally too large for automotive applications operating at 315 MHz. Therefore, automotive designers are forced to use antennas without a balun.

Symmetrical printed meander dipole antenna


A method of non-destructive evaluation of stress corrosion cracking of structural components made of metal alloys, and a method of evaluation of the remaining lifetime of the structural component made of metal alloys are provided, in which a change in properties of the structural components made of metal alloys being used in operating nuclear power plants is measured according to the degree of atomic ordering (or short range ordering) of alloying atoms, and stress corrosion cracking of the structural components made of metal alloys is thus evaluated. The properties to be measured may be one or more selected from a group consisting of hardness, electrical resistivity and thermal conductivity.

All the structural components being used in nuclear power plants that are into contact with coolant water are made from austenitic Fe—Cr—Ni alloys. For example, coolant pipes, core barrels, baffle former bolts are Fe-based austenitic Fe—Cr—Ni alloys such as, for example, 300 series austenitic stainless steels. All these structural components that are into contact with coolant are made from austenitic Fe—Cr—Ni alloys because of their superior resistance to intergranular stress corrosion cracking (IGSCC).
However, when the age of the nuclear power plants exceeds 20 years, austenitic Fe—Cr—Ni alloys turn out to be susceptible particularly to IGSCC in which cracking occurs mainly along grain boundaries. Intergranular (IG) cracking of the structural components in primary water reactor environment is particularly termed 'primary water stress corrosion cracking (PWSCC)' or 'intergranular stress corrosion cracking', while IG cracking in neutron irradiation environment is called 'irradiation assisted stress corrosion cracking (IGSCC)'. The above-mentioned cracking phenomena are often collectively referred to as 'Intergranular (IG) cracking'. As the lifetime of the nuclear power plants is being extended from 40 to 60 years or even beyond, the aging management of nuclear power plants is particularly one of the hot issues to assure the safety of the aged nuclear power plants. From the perspective of the aging management of the nuclear power plants, the core technology particularly relates to the management of IG cracking of the structural components made of austenitic Fe—Cr—Ni alloys which are exposed to primary water.
Unfortunately, no particular technology has been made available so far, in association with the management of IG cracking, albeit either active or proactive, mainly because the intergranular cracking mechanism of austenitic Fe—Cr—Ni alloys has not been fully clarified yet. Instead, the nuclear industry focuses on repair technology of degradated structural components by overlay welding, rather than the proactive management of IG cracking of the structural components itself. Although efforts are made to develop alternative techniques to detect and monitor intergranular cracks in the austenitic Fe—Cr—Ni alloy structural components before propagation of IG cracks into a through-wall crack, IG cracks are too fine to be detected with high reliability by the conventional non-destructive examination techniques. In other words, non-destructive examination techniques to detect and monitor IG cracks of the structural components made of austenitic Fe—Cr—Ni alloys is the core technology for the aging management of nuclear power plants, but no current techniques available so far has fully resolved technical difficulties related to non-destructive examination of IG cracks despite much efforts put forward to date.
Recently, the present inventors showed that austenitic 316L stainless steel, one of the structural materials being used for the structural components of nuclear power plants, had lattice contraction to some extents in reactor operating conditions, due to short range ordering (Young Suk Kim et al., Transactions of the Korean Nuclear Society Autumn Meeting, Jeju Korea, 2010, pp. 1079-1080.)
Accordingly, given the inventors' observation, the inventors proposes a hypothesis that short range order occurring in austenitic Fe—Cr—Ni alloys during plant operation would cause intergranular stress corrosion cracking, and that intergranular stress corrosion cracking susceptibility of the structural components of metal alloys for nuclear power plants can be evaluated non-destructively by measuring variations in their properties accompanying SRO. In short, the inventors attempts to establish the non-destructive evaluation methods to detect and monitor intergranular stress corrosion cracks in the structural components made of austenitic Fe—Cr—Ni alloys and furthermore to assess the remaining lifetime of the structural components made of austenitic Fe—Cr—Ni alloys by accounting for the variations in their properties.

Method of non-destructive evaluation of intergranular stress corrosion cracking (IGSSC) in structural components made of metal alloys, and the method of lifetime evaluation of the structural components


The present invention relates to improvement in a method of supplying a glass ribbon in a molten state to be supplied from a glass melting furnace to a flat glass forming apparatus, which can further improve the smoothness of a flat glass after formed. A glass ribbon 13 supplied from a glass melting furnace 14 to a flat glass forming apparatus 15 is stretched between one pair of tension rollers 24A and 24B in an S-shape and the tension rollers 24A and 24B are rotated while applying a surface pressure to the glass ribbon 13 face via a thin layer of a steam film generated by vaporization of a steam film forming agent. By means of rotation of the tension rollers 24A and 24B, the face of the glass ribbon 13 still in a molten state is polished via the steam film 18.

As a process for producing a flat glass, a tin float process employing molten tin, a pull method, a down draw process, a fusion process and the like have been known.
However, in the above tin float process, since a glass ribbon is floated on a medium having a higher thermal conductivity than glass (on a float bath of molten tin) for forming, the transfer of heat to the medium is significant, and the influence of the temperature of the medium is significant, and accordingly the temperature control of the medium is very important. Further, gradual cooling is required under strict control by making the temperature of the medium close to the temperature of the glass so that the difference in the temperature between the surface and the inside of the glass ribbon during cooling is small. Accordingly, the cooling has to be carried out slowly, an adequately long float bath is required, and accordingly the forming time tends to be long. Further, in view of quality also, various drawbacks derived from tin are likely to occur. Further, exhaustion of tin resource is concerned.
On the other hand, in the pull method, the down draw process and the fusion process, due to forming in a vertical direction, it tends to be difficult to control the force resulting from the gravity to the glass ribbon, whereby it tends to be difficult to control the thickness of the glass, and the temperature control of the medium to decrease the difficulty becomes complicated.
Under these circumstances, the present applicant has proposed a technique relating to a process for forming a flat glass by forming a glass ribbon in a molten state into a plate shape via a thin layer of a steam film by using a base containing a steam film forming agent (hereinafter referred to as "steam float process") (JP-A-9-295819). According to this process for producing a flat glass, such effects as resource saving, energy saving, high quality of the flat glass, decrease in equipment and operation cost, easiness of job change and possibility of variety of applications to small scale production to large scale production, can be obtained.
However, in order to further improve the smoothness of the glass surface of the formed flat glass, in addition to improvement in the forming process in a flat glass forming apparatus, improvement in the supply method capable of improving the smoothness of the glass ribbon in a molten state supplied from a glass melting furnace to a flat glass forming apparatus is required.
That is, the molten glass molten in a glass melting furnace flows as a ribbon shape glass ribbon on a lip face made of bricks at the exit of the glass melting furnace and runs down from the edge of the lip face, and lands on a flat glass forming apparatus. The surface characteristics (particularly roughness) of the lip face are likely to be transcribed to the lip face side of the glass ribbon when it flows on the lip face, and the trace of transcription may have bad influences over the smoothness of the flat glass after formed in the flat glass forming apparatus.
Further, since the viscosity of the glass ribbon which flows on the lip face is not completely the same but slightly changes, the glass ribbon is likely to run down straight down from the edge of the lip face when the viscosity is low, and the glass ribbon is likely to run down while describing a parabola from the edge of the lip face when the viscosity is high. Accordingly, the angle at which the glass ribbon runs down from the edge of the lip face is not stable, thus the glass ribbon pulsates at the edge of the lip face, and the trace of the pulsation may have bad influences over the smoothness of the flat glass. Further, because of unstable angle at which the glass ribbon runs down from the edge of the lip face, not only the landing point of the glass ribbon which lands on the flat glass forming apparatus will not be constant but also the landing impact tends to be significant when the glass ribbon runs down straight down from the edge of the lip face. Accordingly the glass ribbon is likely to be deformed by landing, and this deformation by landing may have bad influence over the smoothness of the flat glass.
The present invention has been made under these circumstances, and it is an object of the present invention to provide a process for producing a flat glass which further improves the smoothness of the flat glass after formed, by improvement in the supply method of a glass ribbon in a molten state to be supplied from a glass melting furnace to a flat glass forming apparatus.


Battery systems are provided according to various embodiments. A battery system includes: a first battery rack including a first battery module having a first battery, a first rack management unit which controls charging and discharging of the first battery module, and a first rack protection circuit which interrupts current of the first battery module under control of the first rack management unit; and a second battery rack including a second battery module having a second battery, a second rack management unit which controls charging and discharging of the second battery module, and a second rack protection circuit which interrupts current of the second battery module under control of the second rack management unit, wherein the first and second rack protection circuits are controlled in parallel by the first and second rack management units.

As battery systems are used in various fields, battery systems having various structures have been introduced. A battery system may include a plurality of battery racks, each of the plurality of battery racks including a rack management unit to manage charging and discharging operations of the battery rack or the like. If a rack management unit of a battery rack among a plurality of battery racks is in an abnormal state, the battery rack including the abnormal rack management unit may be overdischarged or overcharged.


A method for improving primary memory or learning in a mammal comprising administering a 5-hydroxytryptamine receptor agonist which is selective for the 5-hydroxytryptamine-1A receptor subtype, or a pharmaceutically acceptable salt thereof.

This invention relates to a method for improving primary memory and/or learning, employing a 5-hydroxytryptamine receptor agonist which is selective for the 5-hydroxytryptamine-1-A receptor subtype.
Heretofore, various agents have been reported to improve memory. For example, these have included nicotine, caffeine, amphetamine, strychnine and picrotoxin. Additionally, fluoxetine (U.S. Pat. No. 4,647,591) and certain alpha-2I selective adrenergic receptor agonists (U.S. Pat. No. 4,847,300) have been reported as memory improving agents.
Studies have evidenced that the hippocampus plays an important role in learning and memory. Certain electrical activity exhibited by the hippocampus (electroencephalographic (EEG)), in particular the hippocampal theta rhythm (4 to 9 hertz), has been reported to be an important temporal correlate of memory storage and sensory processing. See, e.g. Landfield, P. W., J. L. McGaugh and R. J. Tusa, "Theta Rhythm: A temporal Correlate of Memory Storage Processes in the Rat", Science 175: 87-89, (1972); and Klemm, W. R., "Hippocampal EEG and Information Processing: A special Role for Theta Rhythm", Prog. in Neurobiol. 7, 197-21 (1976). Studies have also evidenced that the hippocampal theta rhythm is predictive of the rate of learning. Berry, S. D. and R. F. Thompson, "Prediction of Learning Rate from the Hippocampal ElectroencePhalogram", Science, 200, 1289-1300 (1978). For additional information as to the role of the hippocampus and memory, reference can be made to Paxinos, George, The Human Nervous System, pp. 745-746 (1990).
It is also well-known that this hippocampal theta rhythm is dependent on cholinergic activity, and treatments that inhibit cholinergic activity inhibit both the theta rhythm and short term memory. Bland, B. H., M. G. Seto, B. R. Sinclair and S. M. Fraser, "The Pharmacology of Hippocampal Theta Cells: Evidence that the Sensory Processing Correlate is Cholinergic ", Brain Research, 229, 121-131 (1984).
Studies have also indicated that 5-hydroxytryptamine (also known as serotonin) has a role in memory and learning, and that certain serotonin reuptake inhibitors can improve memory. See, e.g., Altman, H. J. et al., "Role of serotonin in memory: Facilitation by alaproclate and zimeldine", Psycopharm., 84, 496-502 (1984); and U.S. Pat. No. 4,647,591 (fluoxetine).
5-Hydroxytryptamine (hereinafter sometimes referred to as "5-HT") receptors in the central nervous system (CNS) have been the subject of substantial attention over the past decade. Multiple 5-HT receptor subtypes in the CNS have been identified. Originally, these 5-HT recognition sites were classified into two subtypes. A subset of 5-HT receptors which bound [.sup.3 H]-5-HT with high affinity was designated 5-HT.sub.1, and a subset which bound [.sup.3 H]-spiperone with high affinity was designated 5-HT.sub.2. See, Peroutka, S. J. and Snyder, S. H., Mol. Pharmacol., 16. 687 (1979). Since then, 5-HT.sub.1 receptors have been subdivided into four classes, 5-HT.sub.1A, 5-HT.sub.1B, 5-HT.sub.1C, and 5-HT.sub.1D. See, e.g., Pedigo, N. W. et al., J. Neurochem., 36, 220 (1981); Hoyer, D. et al., Eur. J. Pharmacol., 118, 13, 1985; Peroutka, S. J., J. Neurochem., 47, 529 (1986); and Heuring, R. E. et al., J. Neurosci., 7, 894 (1987). Additionally, another subtype of 5-HT receptor, the 5-HT.sub.3 receptor, has been identified. Further, it has been recognized that 5-HT agonists which act at different 5-HT receptors can product opposite effects in a given system. For example, it is known that both 5-HT.sub.1A and 5-HT.sub.2 agonists effect thermoregulation. However, 5-HT.sub.1A agonists produce a hypothermic response, while 5-HT.sub.2 agonists produce a hyperthermic response. See, Glennon, J. Med. Chem., 30, pp. 1-12 (1987). Furthermore, the differential effects of 5-HT agonists which are selective for specific subtypes is not limited to thermoregulation, but also include other physiological phenomena.
The present invention relates to the use of 5-HT receptor agonists which are selective for the 5-HT-1A subtype (i.e. selective 5-HT.sub.1A agonists) to improve primary memory and/or learning functions. Several such selective 5-HT.sub.1A agonists have been identified and reported in the literature. These selective agonists may be for instance, indoles (see. e.g. U.S. Pat. No. 4,576,959), arylpiperazines, aminotetralins, benzodioxanes, pyrimidinylpiperazines, or aryloxypropanolamines. Perhaps best known thus far is the aminotetralin, 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT), which has been identified as the prototypic selective 5-HT.sub.1A agonist. See, e.g., Glennon, R. A., J. Med. Chem., 30, 1, pp. 1-12 (1987). Several reviews on the subject exist, to which reference may be made for further information as to selective 5-HT.sub.1A and other 5-HT agonists. See, e.g., Robertson, D. W. et al., Annu. Rep. Med. Chem., 23, pp. 49-58 (1988); Johnson, G., Annu. Rep. Med. Chem., 22, 41 (1987); Fozard, J. R., Trends Pharmacol. Sci, 8, 501 (1987); and Green, J., Trends Pharmacol. Sci, 8, 90 (1987).
As to physiological effects, to date, selective 5-HT.sub.1A agonists have been reported to produce hyperphagia and hypothermia, to stimulate sexual behavior, to be anxiolytic, and to cause the 5-HT behavioral syndrome.
No reports have been made that selective 5-HT.sub.1A agonists induce hippocampal theta rhythm and thus may be used as excellently suited agents for affecting and improving primary memory and/or learning functions associated with hippocampal theta rhythm. The present invention is based on the discovery of this phenomenon.

Method for improving primary memory and/or learning


A centrifugal separator includes a cylindrical bowl having a conical lower end with an opening through which feed liquid is injected during a feed mode of operation. The feed liquid is separated into centrate and solids, which accumulate along the inner surface of the bowl. A piston assembly includes a conical piston disposed within the cylindrical bowl, coupled to a piston actuator by a two-part piston shaft. During the feed mode of operation, the piston shaft is disconnected, and the piston is held in an uppermost position by hydraulic pressure from the feed liquid as the bowl is rotated, and a centrate valve on the piston is opened to permit the centrate to flow out to a centrate discharge port. After solids are separated and accumulated on an interior surface of the bowl, the rotation of the bowl is stopped and residual centrate is drained therefrom. In a solids discharge and pumping mode of operation, the piston shaft is connected and the piston actuator urges the piston axially downward, closing the centrate valve and forcing the accumulated solids from the bowl via the opening in the conical lower end of the bowl and into a passage leading to a solids outlet port.

The present invention generally relates to centrifuges and in particular to centrifuges enabling the automatic discharge and pumping of solids that accumulate during separation.
Many different types of centrifugal separators are known for separating heterogeneous mixtures into components based on specific gravity. A heterogeneous mixture, which may also be referred to as feed material or feed liquid, is injected into a rotating bowl of the separator. The bowl rotates at high speeds and forces particles of the mixture, having a higher specific gravity, to separate from the liquid by sedimentation. As a result, a dense solids cake compresses tightly against the surface of the bowl, and the clarified liquid, or "centrate", forms radially inward from the solids cake. The bowl may rotate at speeds sufficient to produce forces 20,000 times greater than gravity to separate the solids from the centrate.
The solids accumulate along the wall of the bowl, and the centrate is drained off. Once it is determined that a desired amount of the solids has been accumulated, the separator is placed in a discharge mode in which the accumulated solids are removed from the separator. In a typical configuration, an internal scraper is engaged to scrape the solids from the walls of the separator bowl.
Prior separators have shortcomings when operating with particular kinds of materials. For example, many separators may not be capable of completely discharging residual solids that are sticky, which can result in poor yield. This can be especially problematic for high-value materials such as are encountered in pharmaceutical processes. Additionally, many separators subject the feed material to very high shear forces when accelerating the feed liquid to the rotational speed of the bowl, which can damage sensitive materials such as pharmaceuticals or biological substances that include intact cells. Other existing separators do not provide a convenient means by which to handle and recover these sensitive materials.
It would be desirable to have a centrifugal separator that can be effectively used with materials of the type described, namely those that result in sticky accumulated solids and those that are sensitive to shear forces generated during the centrifuge process. It would also be useful to have a separator that can easily recover such solids without the possibility of external contamination or additional operator handling.

Conical piston solids discharge and pumping centrifugal separator


An apparatus for stirring which allows automatic coupling of the motor assembly with the stirring shaft. The apparatus comprises a housing, a detachable stirring shaft with an engagement head, and a motor assembly. The motor assembly is fixed onto the housing, and includes a cam assembly having a coupling shaft coupled to a cam device. The cam assembly is adapted to provide an engagement position and a disengagement position of the coupling shaft. The engagement position allows the coupling shaft to engage the stirring shaft when the stirring shaft is placed in a receiving position. A set of gears allows the translation of rotary movement of a motor into the rotating action of the coupling shaft.

Household appliances such as mixers, blenders and food processors typically comprise a housing, a stirring shaft and a mixing bowl. The housing usually includes a head, a stem and a base. Generally, the stirring mechanisms can be divided into two types,
The first type is the top-mixing type, which has the motor and coupling mechanism within the head of the housing of the appliance, such as in bench-top cake mixers. Typically, the head is rotatable, such that one or two stirring shafts have to be manually attached to the coupling mechanism, followed by the placement of the mixing bowl on the base of the housing. The head of the housing is then rotated such that the stirring shaft is rotated into the mixing bowl and points towards the bottom of the mixing bowl. In a variation of this top-mixing design, the head is not rotatable, and the shaft has to be attached manually by the operator having access between the mixing bowl and the head of the housing. This non-rotatable design is often found in industrial scale mixers, which have housing heads containing motors which are too large, heavy or bulky to be conveniently rotated. The advantage of having a top-mixing design is that the base of the housing can contain additional useful function, such as heating or rotating elements. The disadvantage of this design is that a relatively large space must be left between the mouth of the mixing bowl and the head of the housing. In the rotatable head design, this is necessary to give sufficient room for the shaft to be lowered down into the bowl after being attached. In the non-rotatable design, this space is necessary for the operator to access the coupling point with the stirring shaft inside the bowl. As a result, the mixing bowls are often wide and shallow, and cannot be provided with a lid. Because of the need for this space, this top-mixing design is rarely used for high speed mixing of fluids, such as fruit juices or milkshake, since the content may spill easily. In addition, although the base allows for an additional heating element, this is often not included since the hot liquid may also easily spill out from the space present.
In the second type of mixers, such as food blenders, the stirring mechanism is located at the base of the housing. The stirring or cutting blades are typically found coupled to the motor at the bottom of the mixing container. The motor coupled to a coupler is fixed to the base, and upon the proper placement of the container, the stirring blade would be securely coupled to the coupler. This base-mixing design allows the high speed mixing of liquids without the danger of spillage, as the container is usually provided with a lid, However, if heating is required, the heating element would have to be provided from the top, for example, in the form of a heating rod attached to the lid of the container. Such a design is undesirable, because electrical wiring has to be wired to the lid, making the manipulation of the lid both dangerous and cumbersome. In addition, a long heating rod which needs to be removed every time the container is filled and emptied results in great inconvenience and safety hazards.

Apparatus for stirring with automatic shaft coupling mechanism


Provided is a cyanate ester polymer having excellent flame retardance, low dielectric constant, low dielectric loss tangent and high heat resistance. Specifically provided is a cyanate ester polymer obtained by polymerizing a cyanate ester compound represented by the following general formula (1). (1) In the formula, X represents OCN or OH, and 10-100% by mol of X is composed of OCN.

A cyanate ester polymer has a triazine ring formed by polymerization; and owing to its high heat resistance and excellent electric characteristics, the polymer is heretofore widely used as raw materials for various functional polymer materials such as structural composite materials, adhesives, electric insulating materials, electric/electronic parts, etc. However, with the recent requirement for advanced high-level performance in the field of these applications, the requirement for the properties of functional polymer materials has become severer and severer. The properties include, for example, flame retardance, heat resistance, low dielectric constant, low dielectric loss tangent, weather resistance, chemical resistance, low water absorbability, high fracture toughness, etc., but up to the present, these required properties are not always satisfied.
For example, in the field of printed circuit board materials, the materials are required to have a low dielectric constant and a low dielectric loss tangent with the current tendency toward higher frequency for communication frequency and clock frequency, and cyanate resins having excellent dielectric characteristics have become much used. In that situation, from the viewpoint of security of safety against fire, flame retardance must be imparted to them, and bromine compounds having high flame retardance are used. For example, known are bromobisphenol A (see Patent Reference 1), bromophenol-novolak glycidyl ether (see Patent Reference 2), bromomaleimides (see Patent Reference 3), halogen-having monofunctional cyanates (see Patent Reference 4), addition-type bromine compounds having no reactivity with cyanate ester compound (see Patent Reference 5). These bromine compounds have high flame retardance, but may have a risk of generating corrosive bromine or hydrogen bromide through thermal decomposition, and therefore, materials not containing a bromine-based flame retardant are desired.
Accordingly, phosphorus-containing compounds and nitrogen/sulfur-containing compounds are investigated as a flame retardance substitutable for bromine-based flame retardant. For example, as a phosphorus compound often incorporated in epoxy resin, investigated are triphenyl phosphate and resorcinol bis(diphenyl phosphate). However, when incorporated in large quantities, they often lower heat resistance, moisture resistance, water absorbability, etc. For overcoming it, known is a method of adding a phenolic hydroxyl group-having phosphorus compound to a cyanate compound (for example, see Patent References 6, 7, and 8); but the phosphorus compound is also problematic in point of its toxicity. As a nitrogen compound, used are melamine, guanidine, etc.; but when used alone, their flame retardance is insufficient.
On the other hand, a metal hydroxide such as aluminium hydroxide, magnesium hydroxide or the like may be mentioned as a flame retardant; but incorporation of a metal hydroxide may have a risk of lowering dielectric characteristics, heat resistance, impact resistance and moldability. In addition, for example, as in epoxy resin, use of a large amount of an inorganic filler such as spherical fused silica for reducing flammables and for securing flame retardance may take a risk of increasing the melt viscosity of molding materials, thereby lowering the moldability and the substrate wettability thereof to lower the adhesive power, and worsening the dielectric characteristics thereof.
Further, even an antimony-type flame retardant such as antimony trioxide, which is widely used as combined with a bromoepoxy resin, is also problematic in that it is a deleterious substance and therefore has a risk of chronic toxicity. From the above viewpoints, flame retardance of thermosetting resin itself is more desired than before.
For improving heat resistance, low dielectric constant, low dielectric loss tangent, weather resistance, chemical resistance, low water absorbability, high fracture toughness, moldability, adhesiveness and others simultaneously with flame retardance, many trials have heretofore been made. For example, disclosed are a method of producing a cured product having excellent thermal stability by combining a monocyanate and a dicyanate (see Patent Reference 9); and a method of attaining a low dielectric constant and a low dielectric loss tangent by combining a monofunctional cyanate ester compound and a polyfunctional cyanate ester compound (see Patent Reference 10).
Also described is a method of producing a poorly moisture-absorptive, flame-retardant cyanate ester-containing curable resin composition by adding a halogen-containing monofunctional cyanate ester thereto so as to lower the dielectric constant and the dielectric loss tangent of the composition (see Patent Reference 4). The patent reference describes cyanate esters in a broad range, but for keeping their flame retardance, an aromatic monofunctional cyanate ester having bromine as a functional group is an indispensable component, and no one could succeed in improving the flame retardance by the use of a cyanate ester resin alone. As described in the above, these bromine compounds may have a risk of generating corrosive bromine or hydrogen bromide through thermal decomposition.
Also provided are an aromatic cyanate ester compound having at least two rings bonding to each other via an unsaturated group-containing group (see Patent Reference 11), a fluorine-containing dicyanate ester (see Patent Reference 12), a method of using a phenol-novolak-type cyanate ester for attaining flame retardance (see Patent Reference 13), etc. In any case, however, an example of satisfying all of practicable low dielectric characteristics, flame retardance and heat resistance by the use of a cured product of a cyanate ester compound alone is not known.
In case where a cyanate ester is used in laminates for printed circuit boards, first it is dissolved in a solvent such as methyl ethyl ketone to prepare a varnish, and then this is impregnated into a glass cloth and dried to give a prepreg. When the steps are taken into consideration, the solubility of cyanate ester in solvent and the low volatility and the stability thereof in the working process are also important factors.
Patent Reference 1: JP-B 4-24370
Patent Reference 2: JP-A 2-286723
Patent Reference 3: JP-A 7-207022
Patent Reference 4: JP-A 6-122763
Patent Reference 5: JP-A 2000-95938
Patent Reference 6: JP-A 2003-128928
Patent Reference 7: JP-A 2003-128753
Patent Reference 8: JP-A 2003-128784
Patent Reference 9: JP-A 6-228308
Patent Reference 10: JP-A 6-49238
Patent Reference 11: JP-T 2002-531989
Patent Reference 12: JP-A 63-250359
Patent Reference 13: JP-A 2002-206048


In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds.

This invention relates to the field of percussive tools used in drilling. More specifically, the invention includes a downhole jack hammer which may be actuated by drilling fluid.
The prior art has addressed the operation of a downhole hammer actuated by drilling mud. Such operations have been addressed in the U.S. Pat. No. 7,073,610 to Susman, which is herein incorporated by reference for all that it contains. The '610 patent discloses a downhole tool for generating a longitudinal mechanical load. In one embodiment, a downhole hammer is disclosed which is activated by applying a load on the hammer and supplying pressurizing fluid to the hammer. The hammer includes a shuttle valve and piston that are moveable between first and farther position, seal faces of the shuttle valve and piston being released when the valve and the piston are in their respective farther positions, to allow fluid flow through the tool. When the seal is releasing, the piston impacts a remainder of the tool to generate mechanical load. The mechanical load is cyclical by repeated movements of the shuttle valve and piston.
U.S. Pat. No. 6,994,175 to Egerstrom, which is herein incorporated by reference for all that it contains, discloses a hydraulic drill string device that can be in the form of a percussive hydraulic in-hole drilling machine that has a piston hammer with an axial through hole into which a tube extends. The tube forms a channel for flushing fluid from a spool valve and the tube wall contains channels with ports cooperating with the piston hammer for controlling the valve.
U.S. Pat. No. 4,819,745 to Walter, which is herein incorporated by reference for all that it contains, discloses a device placed in a drill string to provide a pulsating flow of the pressurized drilling fluid to the jets of the drill bit to enhance chip removal and provide a vibrating action in the drill bit itself thereby to provide a more efficient and effective drilling operation.


A computerized system and method for the design, execution and tracking of exercise programs including portable microprocessor controlled data controllers to instruct and record the actual computed workout for the user. A data communication link transfers data between the data controllers and a computer hosting application software and database files for the particular user, exercise and exercise regimen to create and display a customizable and comprehensive exercise system designed for the particular user.

A consistent fitness regiment is universally accepted by medical authorities as being instrumental to longevity and good health. There are currently several devices available that monitor an individual exercising on an exercise apparatus. Examples of these are U.S. Pat. Nos. 4,493,485, 4,409,992, and 4,408,183. The problem with these devices is that they are limited to recording the performance the user decides to achieve and provide no instruction on the performance the user should achieve. For example, U.S. Pat. No. 4,493,488 provides a predetermined pace for the user regardless of the user's actual fitness level. Additionally, the aforementioned devices provide no indication of past performance from which a trend can be interpolated. U.S. Pat. No. 4,817,940 does provide the capability to record past performance but makes no provision to automatically calculate future performance requirements based upon that stored information. Additionally U.S. Pat. No. 4,817,940 requires that each piece of exercise equipment be instrumented in order to be accessible by the device.
A key element to a fitness program is the ability to continually challenge the body physically. When a person has performed an exercise at a consistent level, the muscles tend to acclimate to the particular exercise and plateau at the level of development required to maintain the exertion level. In order to advance the development of the muscles involved, the exertion level must be increased at specific intervals. Without continual professional instruction, most amateur fitness enthusiasts lack the basic knowledge to determine when and by how much to advance their workout parameters to achieve maximum effectiveness.
The System described herein allows the Trainer to impart a training philosophy to each exercise. The Trainer can specify up to four actions to be performed, automatically, on specified exercise dependent parameters (pounds of weight, repetitions, sets, etc.) when specified events (completed routines, elapsed days, etc.) occur. The Trainer can have a parameter increase, decrease, or the exercise completely removed from the workout when the specified event occurs. The events are user selectable using dynamically compiled lists and numeric entry fields. Each time client's daily workout routine is requested, the System will compute the new parameters for each exercise using the exercise's philosophy settings, the performance of the last workout session, and the current date. The end result is a workout program that adapts to the client's actual workout performance achieving the desired result without the client possessing a prerequisite knowledge of exercise training or cost of a private trainer each workout session.
The current most popular method of displaying and recording an exercise fitness program involves a cardboard sheet depicting a list of exercises, initial setup parameters, and columns representing workout sessions. The user must manually mark the repetitions, sets, or other work performed for each corresponding exercise. The end result is a very crowded matrix that reveals little trend information and requires manual computation to determine future performance goals. Storage of these sheets may become cumbersome, especially for a large client population.
The System will eliminate the paper workout sheet and replace it with compact portable battery powered computerized Digital Training Assistants (DTAs). Each DTA is dynamically programmed with the user's own fitness routine calculated for the specific workout session. The DTA unit will interactively instruct the user on both the sequence of exercises to be performed as well as the exercises setup and desired performance parameters. A keypad interface to modify parameters is provided to permit recording of the actual work performed. The resultant exercise information is downloaded back to the System where it becomes a permanent part of the user's individual workout performance history database file. The file's data will be used in the computation of the next workout session's exercise performance parameters.
Determining past performance trends using the traditional paper method of parameter recording requires manually graphing data points. This becomes increasingly impractical with increasing number of workouts. The user will often not increase the workout parameters over time or even worse, increment parameters regardless of the actual fitness level attained.
By utilizing the detailed exercise data in the client's individual workout performance history database file, several reports and graphs can be produced with the speed and accuracy of a computerized system. This gives a new level of instant feedback not previously available in the Fitness Club environment. The client is now able to determine the apparent effectiveness of his workout routine and become more connected to his workout by virtue of the near real-time reporting capability of the System. Enthusiasm and involvement are both enhanced.
A common problem with personal trainers at a fitness club is that each trainer will impart their own individual exercise fitness philosophy onto a client. The result being that any two clients trained by different trainers will have differing fitness programs and varied results. There is a loss of standardization within the club and each new trainer adds to the problem. A method of standardizing the training philosophies using a collective expertise is needed within the industry.
The proposed system will allow the Head Trainer to impart his/her training expertise to each Assistant Trainer by mandating that the trainers implement one of the stored exercise routine templates when training a client. The System will allow different exercise templates to be constructed using the equipment and exercises found at the facility. Each template's exercises may have corresponding parameter increasing/decreasing philosophies designed by the Head Trainer as well.
Accuracy in reporting a client's workout performance is another problem encountered by trainers. When a client is not being monitored personally by a trainer, the client is then responsible for remembering and recording the actual work performed. The client must also be aware of the parameters to record and the correct terminology. The Trainer must then be apprised of the client's performance so that he/she may make adjustments as required.
The DTA units allow the client to easily record the actual work performed. Even if a client is unable to complete the exercise as prescribed and displayed, the actual work performed is easily input to the DTA using a numeric keypad and associated function keys. The DTA will prompt the client to make the entry and alert him of any input errors with the required corrective action. The edited workout routine is then downloaded, with computer accuracy, to the System. The changes are instantly noted by the System and adjustments are automatically made.
Currently, at a moderate sized fitness club, the client to trainer ratio is worse than 40 to 1. Most client's are reluctant to incur the additional cost of a Personal Trainer at each session as well as the inconvenience of having to schedule workouts around a trainer's availability. The result is a vast majority of a club's clientele are not taking advantage of the trainers. A potential loss of revenue for the club.
When utilizing the System, the trainers effectively multiply their presence and utility. This is accomplished by having many clients operating the System and DTAs, following the trainer's designed workout program. The automatic parameter philosophy incrementing/decrementing function will ensure that the client is receiving the maximum benefit of the exercise program as if the trainer were always present to make those adjustments in person. An initial trainer/client session for setup and instruction on usage will increase facility's trainer exposure and periodic fitness program checkups ensure further trainer usage.
Currently, a trainer would have to interview and review the workout sheets for several clients to determine if a particular training regiment is performing as prescribed. This is a labor intensive endeavor demanding a large portion of the trainer's work hours. It is to both the trainer's and client's benefit to maximize the effectiveness of a workout routine.
The system will allow the trainer to asses the effectiveness of a workout program by virtue of the system's recording and reporting capabilities combined with the ability to simultaneously look at several different client's and their corresponding demographics. Performance graphs give easily understandable trend analysis useful in determining the effectiveness of the regiment. The trainer may now fine tune the routine to achieve maximum effectiveness.
The comprehensive database capabilities of the system will allow the creation of equipment usage reports charting the number of clients using a particular piece of exercise equipment during a particular week throughout a calendar year this will provide more accurate maintenance scheduling and equipment utilization data.
Demographic and medical information for a client is instantly available to the Trainer as well as the ability to create reports for membership analysis. Such information is very useful in planning promotions and configuration of the facility to better match the client's requirements.

Computerized system for the design, execution, and tracking of exercise programs


A technique for providing a method and apparatus for selecting a route to a destination for a data packet based on routing metrics received in response to a bid broadcast on a network.

1. Field of the Invention
The present invention relates to the field of data packet delivery across a network and, more specifically, to a bidding algorithm that solicits bids for routing the data packets across the network.
2. Background of the Related Art
The basic practice of exchanging data packets over a communication link is generally known in the art. However, there is an ongoing discussion in the industry for the best way to route packetized data, such as for IP telephony or telephone calls, within the border gateways. The current Border Gateway Protocol (BPG) will have difficulty in routing E.164 calls among the autonomous systems (such as ISPs and large organizations), primarily because the E.164 address spaces are geographically based and separate from the IP address spaces. Hence, there is contention among the autonomous systems for routing the E.164 calls.
The prior art practice requires the use of long and complicated routing tables which list the various links necessary to reach the destination. The use of the table may incur significant delay in looking for an address entry. The delay may be acceptable for text data, but inadequate for voice data over the network. Further, on top of this routing table is a complicated policy layer that sets the conditions and policies for exchanging the data packets between the two destinations, which typically introduces further complexity and delay.
Additionally, when multiple autonomous systems are present, who can provide multiple pathways to the destination, there currently is a lack of adequate contention resolution among the autonomous systems for delivering the packets. Accordingly, it is appreciated that some means of providing for an open contention resolving mechanism at the border gateways would allow for competition among the autonomous systems and may reduce the delay encountered at the border gateway. The present invention describes a contention resolution mechanism based on a bidding algorithm for determining the most desirable route for the transfer of a data packet.
The present invention describes a method and apparatus for selecting a route to a destination for a data packet. A broadcast is initiated for a request for a bid to transfer the data packet on a network where there are more than one path to the destination. Then, at least one bid is received in response to the broadcast, in which the bid includes a routing metric associated with the transfer of the packet to the destination through a particular path. A desired path to the destination is selected, based on the received routing metric(s).

Packet network route selection method and apparatus using a bidding algorithm


A tunable optical fiber device comprises a length of fiber having a core having a certain refractive index; a cladding peripherally surrounding the core with a refractive index less than the refractive index of the core; and at least one hollow region disposed within the cladding in proximity to the core or within the core itself. Fluid (typically liquid) controllably moved within the hollow region modifies the effective index of the fiber and thereby tunes its characteristics.

Optical fibers are useful for many applications in modern communications systems. A typical optical communications system comprises a transmitter of optical signals, a length of transmission optical fiber coupled to the source, and a receiver coupled to the fiber for receiving the signals. One or more amplifying systems may be disposed along the fiber for amplifying the transmitted signal. Filters and attenuators are required in these systems to change the power levels of various signals.
Basically, an optical fiber is a strand of waveguiding glass comprising an inner core having a certain index of refraction and an outer cladding peripherally surrounding the core. The cladding has a lower index of refraction than the core. As long as the refractive index of the core exceeds that of the cladding, a light beam can be guided along the length of the core by total internal reflection. Since the light is confined mostly in the core region, the ability to externally effect propagation behavior of the light is significantly limited. With conventional fibers, to change the propagation behavior of light in the core, one is essentially limited to the application of strain and/or temperature changes to the fiber.
Optical fiber gratings are important elements for controlling light within fibers. A fiber grating typically comprises a length of fiber including a plurality of substantially equally spaced optical grating elements such as index perturbations, slits or grooves. Such gratings include long period gratings and Bragg gratings.
A long period grating couples optical power between two copropagating modes with very low back reflections. It typically comprises a length of optical waveguide wherein the refractive index perturbations are spaced by a periodic distance Λ which is large compared to the wavelength λ of the transmitted light. In contrast with Bragg gratings, long-period gratings use a periodic spacing Λ which is typically at least 10 times larger than the transmitted wavelength, i.e. Λ≧10λ. Typically Λ is in the range 15–1500 micrometers, and the width of a perturbation is in the range ⅕ Λ to ⅘ Λ. In some applications, such as chirped gratings, the spacing Λ can vary along the length of the grating. Long-period gratings are particularly usefull in optical communication systems for equalizing amplifier gain at different wavelengths. See, for example, U.S. Pat. No. 5,430,817 issued to A. M. Vengsarkar on Jul. 4, 1995.
A fiber Bragg grating comprises a length of optical fiber including a plurality of perturbations in the index of refraction. These perturbations selectively reflect light of wavelength λ equal to twice the spacing Λ′ between successive perturbations times the effective refractive index, i.e. λ=2neffΛ′, where λ is the vacuum wavelength and neff is the effective reactive index of the propagating mode. The remaining wavelengths pass essentially unimpeded. Bragg gratings have found use in a variety of applications including filtering, adding and dropping signal channels, stabilization of semiconductor lasers, reflection of fiber amplifier pump energy, and compensation for waveguide dispersion.
Many potential applications require optical gratings having characteristics which are tunable. A tunable long period grating can provide dynamic gain compensation. Tunable Bragg gratings can permit dynamic control of which wavelength will pass through the grating and which will be reflected or diverted.
As may be appreciated, those concerned with the development of optical communications systems continually search for new components and fiber designs. As optical communications systems become more advanced, there is growing interest in new methods and devices for modulating, filtering, attenuating and switching wavelength channels. The instant invention provides a new structure for a tunable optical fiber devices including tunable fiber gratings.

Tunable microfluidic optical fiber devices and systems


In deep submicron memory arrays there is noted a relatively steady on current value and, therefore, threshold values of the transistors comprising the memory cell are reduced. This, in turn, results in an increase in the leakage current of the memory cell. With the use of an ever increasing number of memory cells leakage current must be controlled. A method of manufacture of a dynamic threshold voltage control scheme implemented with no more than minor changes to the existing MOS process technology is disclosed. The disclosed invention controls the threshold voltage of MOS transistors. Methods for enhancing the impact of the dynamic threshold control technology using this apparatus are also included. The invention is particularly useful for SRAM, DRAM, and NVM devices.

1. Technical Field
The invention relates generally to MOS based memory cells. More specifically, the invention relates to the improvement of leakage of memory cells using deep submicron MOS transistors.
2. Description of the Prior Art
Conventional complementary metal-oxide semiconductor (CMOS) technology currently poses some difficult problems as the minimum feature size shrinks to below 100 nanometers and power supply voltage is reduced to less than 1.0V. A typical layout of a 0.18 micron transistor 100 is shown in FIG. 1. The transistor is manufactured over a well 110 where a diffusion area 120 is created. The gate 130 of the transistor 100 is formed over an island 120, and has a length "L" and width "w." For example, 0.18 micron is the minimum gate length for a transistor in a 0.18 micron technology, with the width of the transistor varying for different circuit applications. Contacts 140 and 141 comprise one terminal of the NMOS transistor, for example the drain, and a contact 150 provides another terminal of the transistor 100, for example the source. The contact 131 is connected to the gate 130. There are other minimal feature sizes, such as a minimal size for the well "x," and a minimum distance from the edge of the well to the diffusion area 120 marked as "y." Dimensions, such as "w," "x," and "y" are generally process dependent. Power supply voltage is reduced in correspondence with the minimum feature size to maintain a limit on the electrical field across the oxide. Therefore, power supply voltage has decreased from 3.3V for 0.35-micron CMOS technology to 1.8V for 0.18 micron technology, and is further expected to be at the 1.0V level for 100 nanometers CMOS technology. While power supply voltage decreased, the threshold voltage of the NMOS transistors stayed between 0.45V and 0.35V. The relationship between the NMOS threshold voltage Vth and CMOS power supply VDD is known to be very critical. The threshold voltage determines the leakage current, Ioff, of the transistor when it is in its OFF state. As the threshold voltage is driven lower, the leakage current increases.
The drain current of the transistor is a direct function of the overdrive of the transistors, measured as the difference between power supply VDD and threshold voltage Vth. The drain current of the transistor determines the time required to charge the load capacitance from ground to the level of power supply VDD. This overdrive voltage has decreased constantly as the power supply decreased from 3.3V to 1.0V, while threshold voltage decreased only from 0.45V to 0.35V. For the 0.1 micron technology, the threshold voltage of the transistors is being scaled below 0.35V at the expense of very high OFF stage leakage current IOFF which ranges between 10 nA to 100 nA for a transistor with equal gate length and width, or W/L ratio of 1. For a transistor with a gate width to length (W/L) ratio of ten, the OFF current increases to ten times the value stated above, i.e. from 100 nA to 1000 nA. For a CMOS technology of 0.1-micron minimum feature size, a typical VLSI chip is expected to contain over 100 million gates. Given a leakage at every gate of 1 microamperes, there is 100 amperes of leakage current.
A scheme to control the threshold voltage dynamically has been proposed by Takamiya et al. in an article titled High Performance Electrically Induced Body Dynamic Threshold SOI MOSFET (EIB-DTMOS) with Large Body Effect and Low Threshold Voltage. Takimiya et al. suggest a scheme that shorts the gate and the substrate of the transistors, thereby causing the substrate voltage of the transistor to increase as the gate voltage is increased for a n-channel MOS (NMOS) transistor. This scheme is proposed for NMOS transistors fabricated on silicon-on-insulator (SOI) substrates, where the transistor substrate is totally isolated. This scheme manipulates the threshold voltage by changing the bias of the substrate in the positive direction for a NMOS transistor, along with a positive signal at the gate. As the substrate to source voltage becomes positive, the depletion layer width is reduced. This results in lower threshold voltage of the transistor, thereby increasing the current from the transistor. In the native form, the Takamiya et al. invention is applicable only for circuits using a power supply voltage of less than 0.6V because this scheme turns on the substrate-to-source diode, and the leakage from this diode must be limited. Otherwise one type of leakage would be traded for another, i.e. from drain-to-source leakage to substrate-to-source leakage. The changes in the threshold voltage of a MOS transistor, upon application of voltage to the substrate or the well region, is known as the body effect. A large body effect allows the changes in threshold voltage to be magnified upon application of bias to the substrate (well).
Douseki in U.S. Pat. No. 5,821,769 describes a method for the control of the threshold voltage of a MOS transistor by connecting a MOS transistor between the gate and the substrate to control the threshold voltage. The Douseki invention requires the addition of another transistor for every transistor whose threshold voltage is dynamically controlled. The adjusted threshold voltage is fixed by the power supply voltage and the threshold voltage of the additional transistor. The area penalty is fairly large for the Douseki invention and it requires additional process steps.
Notably, MOS technology has enabled the increase in the density of semiconductor memory chips with every step of scaling down of the minimum geometry of the transistors. The increase in density has taken place for dynamic random access memory (DRAM), static random access memory (SRAM), and non-volatile memory (NVM) chips. In fact, the memory chips have proven to be a major driver in shrinking geometry of MOS transistors. With the transistor minimum dimension scaled below 100 nanometers, the density of dynamic random access memory has reached four gigabits. The maximum current conducted by the transistor, ION is not increasing rapidly due to various second order effects that are becoming dominant. As a result, the transistors are being designed with lower threshold voltage VTH. This results in the increase of the leakage current IOFF.
FIG. 2 illustrates a typical SRAM element, also known as SRAM cell. This cell consists of two cross-coupled CMOS inverters consisting of NMOS transistors 222 and 224 and PMOS transistors 212 and 214. The memory cell is accessed using the pass transistors 226 and 228. These six transistors form a static random access memory. The PMOS transistors are formed in a n-well 232, which is shared by a certain number of SRAM cells. The cell is powered by the power bus, a metal line marked 242, and the ground connection is provided by the bus 244. The data to the cell are read and written by bit lines 246, representing the bit line value itself, and line 248 representing the inverse value of bit line 246, otherwise also know as a bit-line bar.
It is well known to those skilled in the art that SRAM cells, such as the SRAM cells shown in FIG. 2, are critically dependent upon the ratio of ION to IOFF, and a higher value of this ratio is desirable for the stability of the memory cell. With the lowered ratio of ION to IOFF, memory cells are not very stable and are subject to change of their state, or flipping, due to small electrical disturbances. Similarly, DRAM devices are also dependent upon the conducting characteristics of the MOS transistors. In a DRAM, a capacitor for storing the charge is used, and a transistor acts as a gating element to make or break the electrical connection to the capacitor. These pass transistors are designed with a high threshold voltage so that the off current of these transistors is low. This results in lowering of the ON current of these transistors, which leads to decrease in the read and write speed to the DRAM.
A similar problem also exists in other semiconductor memory types, including non-volatile memory, three-transistor SRAM, multi-port SRAM, and other types known to those skilled in the art. Prior art solutions have further attempted to address these issues. However, these approaches have caused significant increases in die area, reduced other beneficial characteristics of the devices, and require changes in the manufacturing process, as well as other limitations. There is therefore a need in the art for a technology which can reduce the leakage of memory cells using deep submicron MOS transistors, without adversely affecting other characteristics of the memory cell. Preferably such a solution will not change standard manufacturing processes and, preferably, such technology will be further applicable to multiple types of memory cells.

Method of manufacture of an apparatus for increasing stability of MOS memory cells