An upright concrete wall panel form apparatus includes a back panel form to be secured to a base in an upright position, an adjustable support assembly to be secured to the base adjacent the back panel form, and a movable front panel form supported by the adjustable support assembly in an upright position. The movable front panel form is moveable via the adjustable support assembly between a concrete wall panel prep area position and a concrete wall panel forming position. The movable front panel form is aligned with the back panel form in the concrete wall panel forming position so as to define a gap therebetween to receive concrete for forming at least one concrete wall panel in an upright position.

Tilt-up concrete wall panel construction may be used to construct buildings, such as warehouses and factories, retail and convenience stores, for example. In general, tilt-up concrete wall panel construction uses a concrete wall panel form on a suitable flat surface, which may be the building floor slab or a temporary casting slab. After steel reinforcing bars (rebar) or other reinforcement are placed in the form, the form is filled with concrete.
After the concrete cures, the concrete wall panel form is removed and the concrete wall panels are tilted-up and lifted into place to form a wall section. The concrete wall panels may also be referred to as precast panels. Numerous wall sections generally are attached together and to framing members of the building to form complete walls.
Concrete wall panels vary in height, such as from 8 to 36 feet, for example. As the concrete wall panels increase in height, so do the wall thicknesses. An increased wall thickness for taller concrete wall panels avoids breakage as the walls are titled-up. For example, the wall thickness of a 36 foot tall concrete wall panel is several inches more than the wall thickness of a 16 foot tall concrete wall panel.
Since extra concrete is needed for the taller concrete wall panels, this increases construction material costs. In addition, there may also be an increase in operating costs for the larger cranes having the capacity to handle the taller concrete wall panels with the increased thicknesses.
Other factors to consider are the area needed for the concrete wall panels to be formed and the critical construction path needed for forming the building. In standard tilt-up construction, the concrete wall panels are either poured on top of a temporary slab (i.e., a base) built specifically for this purpose outside of the building to be built or on top of the floor slab inside of the building being built.
When the concrete wall panels are poured on the base, a large area is required. This area is at least equal to the size of the largest concrete wall panel being formed. Sometimes the area needed for the base is not always available. After the concrete wall panels have been formed, the base needs to be demolished and removed.
When the concrete wall panels are poured on top of the floor slab of the building being built, the pouring of a next concrete wall panel cannot start until that floor slab has been poured and cured. This adds time to the construction of the building. Also, the concrete wall panel sits right in the middle of a critical construction path. Consequently, there is a need to reduce the construction time and costs associated with providing concrete wall panels used to form the walls of a building.

Upright concrete wall panel form apparatus and associated methods


A control device and a control method can quickly estimate a self-location even when the self-location is unknown. In a case of storing information supplied in a time series detected by LIDAR or a wheel encoder and estimating a self-location by using the stored time-series information, when a position change happens unpredictably in advance such as a kidnap state is detected, the stored time-series information is reset, and then the self-location is estimated again. Example host platforms include a multi-legged robot, a flying object, and an in-vehicle system that autonomously moves in accordance with a mounted computing machine.

In order to realize autonomous movement of a mobile object such as a robot, it is necessary to recognize and estimate a self-location, which is a starting point for planning an action. Therefore, there has been proposed a technology for recognizing a situation around the self by means such as a sensor, estimating a self-location, and planning an autonomous movement.
For example, in a case of sequentially estimating a self-location by using information on a self-location continuously detected in the past, in a case where a self-location has been moved by some external force to a self-location completely different from a previous tendency of the self-location, continuity with the past self-location information is lost, which causes a state of being unable to recognize the self-location.
Therefore, there has been proposed a technology for correcting a multiplex state information to calculate final location information of a mobile device and reflecting a moving distance during a kidnap, when an abnormal movement state such as a slip or a kidnap (a state where the self-location cannot be recognized) occurs, which is a state where the self-location cannot be recognized (see Patent Document 1).
Furthermore, there has been proposed a technology for monitoring a fluctuation due to a difference between a control input amount related to traveling and an actual movement amount, and stopping traveling when the fluctuation deviates from a controllable range due to a disturbance and the self-location cannot be recognized (see Patent Document 2).

Control device and control method, program, and mobile object


A scrapbook workstation includes a base workstation member including a first plurality of adjustable shelves, at least one bi-fold door rotatably coupled to the base workstation, and a collapsible table rotatably coupled to the base workstation member, wherein the at least one bi-fold door further comprises a second plurality of adjustable shelves formed in a first panel and a coupling board formed on a second panel.

Compiling scrapbooks or picture albums of memories or artwork has been a tradition in family homes for centuries. There are two common complaints about assembling scrapbooks. One complaint is that there is not enough room to make and work on a scrapbook. Another complaint involves getting all the tools and associated components out to work on the scrapbook or craft and putting it all away each time a person has finished working on their scrapbook, which can be very time consuming.
The following design patents illustrate ornamental designs of various desks. U.S. Des. Pat. No. 376,491, issued to James O. Kelley on Dec. 17, 1996, illustrates a computer secretary. The ornamental design includes two separate compartments enclosed by four doors. The compartments include shelves, drawers, and a work surface, but does not include a bifolding door. U.S. Des. Pat. No. 376,496, issued to Kelly, et al. on Dec. 17, 1996, illustrates a computer workplace having one major compartment enclosed by two doors, not bi-fold doors.
The following patents disclose various types of desks and work stations. U.S. Pat. No. 1,099,521, issued to Abbe Sprung on Jun. 9, 1914, describes an office desk including a pigeon hole rack in which letters or papers may be quickly filed. It has an ordinary flat top desk which may raise the pigeon hole rack by a trip element actuated by the operator.
U.S. Pat. No. 5,121,974, issued to Alan R. Monson on Jun. 16, 1992, describes a computer desk apparatus with parallel walls formed with a front wall defining a central cavity. The central cavity is positioned between a right series of storage drawers and a left storage door positioned hingedly in front of a printer cavity which further includes a medially positioned slide-out drawer. Extending upwardly from a lower desk plate are right and left storage shelves. The upper cavity includes a roll-top member directed over the cavity to provide protection for the organization when not in use.
U.S. Pat. No. 5,590,940, issued to Michael B. Richard on Jan. 7, 1997, describes a sliding rack cabinet for dressers. The cabinet includes a rectilinearly shaped cabinet member having a peripheral edge wall. The back wall is connected to and spanning the peripheral edge wall. A tie is rack mounted to the peripheral edge wall adjacent to the top edge wall.
U.S. Pat. No. 5,695,264, issued to David T. Koch on Dec. 9, 1997, describes a portable office unit with an enclosure that includes two hingedly connected shells. U.S. Pat. No. 5,738,422, issued to Welborn, Jr. et al. on Apr. 14, 1998, describes a computer work station which includes a first desk unit with a front tapered edge. The first desk unit has an electrical control panel with surge protected outlets. The work station has a second desk unit, one end of the second desktop being inserted into and supported by a support rail in a bookcase and the other end being placed upon and secured to a file cabinet.
U.S. Pat. No. 5,842,758, issued to James O. Kelley on Dec. 1, 1998, describes a sky cabinet work station having a pair of opposing side panels which have vertically oriented elongated members. The top includes a transparent or translucent panel which is adapted to transmit light through the panel to illuminate the work station.
U.S. Pat. No. 5,678,905, issued to James O. Kelley on Oct. 21, 1997, and U.S. Pat. No. 5,927,833, issued to James O. Kelley on Jul. 27, 1999, both describes a concealed desk which comprises a desktop or work surface with supporting side panels, a kneehole opening, and storage compartments. The front of the desk is enclosable by folding doors mounted on front side edges of the desk's side panels.
When the doors are opened, the doors preferably fold against the side panels of the desk and do not obstruct either the appearance or the use of the desk. The desktop surface of the desk is concealed by an upper storage unit that is mounted on the desktop or that comprises an extension of the desk, above the desktop or work surface. Full lengths doors enclose both the upper and lower portions of the desk to give the furniture the appearance of an armoire. French Pat. No. 2,650,494, published Feb. 8, 1991, describes a work place for a computer having lower shelving and storage units.
With the increasing popularity of showcasing photos and memorabilia in attractive keepsake albums and scrapbooks, the need for a compact space saving workstation that is visually attractive has increased. However, due to the space needed for scrapbook and photo album work, the traditional workstations mentioned above are unable to accommodate the need for space.

Adaptable bi-fold scrapbook and craft workstation


The present invention provides an improved process for continuously casting aluminum alloys and improved aluminum alloy compositions. The process includes the steps of (a) heating the cast strip before, during or after hot rolling to a temperature in excess of the output temperature of the cast strip from the chill blocks and (b) stabilization or back annealing in an induction heater of cold rolled strip produced from the cast strip. The alloy composition has a relatively low magnesium content yet possesses superior strength properties.

Aluminum beverage containers are generally made in two pieces, one piece forming the container sidewalls and bottom (referred to herein as a "container body") and a second piece forming a container top. Container bodies are formed by methods well known in the art. Generally, the container body is fabricated by forming a cup from a circular blank aluminum sheet (i.e., body stock) and then extending and thinning the sidewalls by passing the cup through a series of dies having progressively smaller bore sizes. This process is referred to as "drawing and ironing" the container body. The ends of the container are formed from end stock and attached to the container body. The tab on the upper container end that is used to provide an opening to dispense the contents of the container is formed from tab stock.
Aluminum alloy sheet is most commonly produced by an ingot casting process. In the process, the aluminum alloy material is initially cast into an ingot, for example, having a thickness ranging from about 20 to about 30 inches. The ingot is then homogenized by heating to an elevated temperature, which is typically 1075.degree. F. to 1150.degree. F., for an extended period of time, such as from about 6 to about 24 hours. "Homogenization" refers to a process whereby ingots are raised to temperatures near the solidus temperature and held at that temperature for varying lengths of time. Homogenization reduces microsegregation by promoting diffusion of solute atoms within the grains of aluminum and improves workability. Homogenization does not alter the crystal structure of the ingot. The homogenized ingot is then hot rolled in a series of passes to reduce the thickness of the ingot. The hot rolled sheet is then cold rolled to the desired final gauge.
Although ingot casting is a common technique for producing aluminum alloy sheet, a highly advantageous method for producing aluminum alloy sheet is by continuously casting molten metal. In a continuous casting process, molten metal is continuously cast directly into a relatively long, thin slab and the cast slab is then hot rolled and cold rolled to produce a finished product.
Some alloys are not readily continuously cast into an aluminum sheet that is suitable for forming operations, especially for making drawn and ironed container bodies. By way of example, some alloys have striated grain structures which lead to a number of problems. During fabrication, the aluminum alloy sheet produced from such alloys can generate unacceptably high amounts of fine particles, which cause a significant increase in the rate of wear to fabricating equipment. Striated grains further cause a high degree of variability in physical properties across a given sheet and among coils of sheets. Other alloys have a low degree of formability, an unacceptably high earing and/or undesirable strength properties.
It would be desirable to have a continuous aluminum casting process in which the aluminum alloy sheet can be readily fabricated into desired objects. It would be advantageous to have a continuous casting process in which the aluminum alloy sheet has an equiaxed as opposed to a striated grain structure. It would be advantageous to have an aluminum alloy sheet that generates a low amount of finely sized particles during fabrication. It would be advantageous to have an aluminum alloy sheet that has a high degree of formability, low earing and high strength.

Continuously annealed aluminum alloys and process for making same


A transceiver with an antenna oscillating circuit generates a magnetic field which inductively charges a charge capacitor of a transponder through a transponder oscillating circuit. A frequency-modulated oscillation is thereupon generated in the transponder and that oscillation is transmitted back to the transceiver. In order to ensure that the transceiver will receive the highest possible amplitudes of the frequency-modulated oscillation, the resonant frequency of the antenna oscillating circuit is adapted to the oscillation frequencies of the transponder oscillating circuit. To that end, an impedance is connected, automatically weighted, to the antenna oscillating circuit.

1. Field of the Invention
The invention relates to an anti-theft system for a motor vehicle. In particular, it pertains to a locking system through which an immobilizer of the motor vehicle is released
An anti-theft system which is known from German Patent DE 44 30 360 C1 has a portable transponder that carries code information. An antenna disposed in the motor vehicle is part of an oscillating circuit that is amplitude-modulated by an oscillating circuit in the transponder If no modulated oscillation is detected on the vehicle side, then the oscillating circuit is mistuned, so that the next time an attempt is made, a modulated oscillation will be detected That can be carried out by varying the exciter frequency or the resonant frequency of the oscillating circuit.
2. Summary of the Invention
It is accordingly an object of the invention to provide an anti-theft system for a motor vehicle, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and in which a frequency-modulated transmitted signal of a transponder is detected as well as possible.
With the foregoing and other objects in view there is provided, in accordance with the invention, an anti-theft system for a motor vehicle, comprising a transceiver to be stationarily disposed in a motor vehicle, the transceiver having an antenna oscillating circuit with components including an antenna, the antenna oscillating circuit having a resonant frequency determined by the components; an oscillator imposing an oscillation on the antenna oscillating circuit for transmitting energy signals; a portable transponder having a transponder oscillating circuit oscillating at two different resonant frequencies as a function of code information, the portable transponder having an energy reservoir charged by the energy signals for transmitting the code information back to the transceiver with the aid of the oscillation of the transponder oscillating circuit; an evaluation unit receiving the oscillation generated by the transponder and received by the transceiver, the evaluation unit detecting the received oscillation and outputting the code information; a comparator demodulating and comparing the code information from the evaluation unit with desired code information and issuing a release signal for a security unit if the code information and the desired code information correspond; and the resonant frequency of the antenna oscillating circuit being adapted as a function of the transmission of the energy signals or of the reception of the oscillation to a frequency between the two resonant frequencies of the transponder oscillating circuit.
Accordingly, a transmitter in the vehicle has an oscillating circuit, which is inductively coupled with an oscillating circuit of a portable transponder in a key. In the transmitters a magnetic field or an energy signal is generated and is transmitted to the transponder where it charges the energy reservoir. By discharging the energy reservoir, a frequency-modulated transmitted signal is generated in the transponder and it is transmitted by transformer to the vehicle oscillating circuit. In order to ensure that the transmitted signal or oscillation will be reliably detected, the resonant frequency of the vehicle oscillating circuit is adapted to the resonant frequency of the transponder oscillating circuit, with the aid of an amplifier circuit.
In accordance with another feature of the invention, the antenna of the antenna oscillating circuit is a transmitter coil, the antenna oscillating circuit has capacitor connected parallel to the transmitter coil, and there is provided a circuit configuration, and an impedance connected in weighted fashion through the circuit configuration to the antenna oscillating circuit.
In accordance with a further feature of the invention, the circuit configuration is an amplifier having a voltage gain connecting the impedance in weighted fashion.
In accordance with an added feature of the invention, the circuit configuration is connected parallel to the impedance.
In accordance with a concomitant feature of the invention, the impedance has a series and/or parallel circuit of a capacitor and/or a coil and/or a resistor.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an anti-theft system for a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.


An integrated circuit current shunt amplifier (2A) includes an amplifier (9) having a (+) input connected to a first terminal (5A) of a shunt resistor (RSHUNT). An output transistor (24) has a gate coupled to an output of the amplifier, a source coupled to a (−) input of the amplifier, and a drain coupled to a first terminal of an output resistor (ROUT). A gain resistor (RGAIN) is coupled between the (−) input of the amplifier and a second terminal of the shunt resistor. The gain resistor has a temperature coefficient which is essentially the same as that of the shunt resistor. A voltage regulator (26) can be coupled between the second terminal of the shunt resistor and a low-side supply voltage terminal (27) of the amplifier. A charge pump (30) can provide a below-ground voltage on a second terminal of the output resistor. A difference amplifier (31) coupled to the drain and referenced to the below-ground voltage produces an output voltage (Vout) referenced to ground.

The present invention relates generally to current sensing amplifiers, and more particularly to a current sensing amplifier which is capable of accurately sensing current flowing through a trace conductor on a printed circuit board (PCB) and providing instant, automatic temperature compensation of the sensed value by means of a gain resistor that is included within the current sensing amplifier and is composed of essentially the same kind of material as the trace conductor.
It would be desirable to have a highly accurate current sense amplifier that can be used when there is a need for precise measurement of current flowing in a PCB conductor. Furthermore, even if a particular application does not require accurate measurement of the amount of current flowing into a load to accomplish a primary function of the application, it nevertheless often is desirable to have an accurate, temperature-compensated value representing the voltage drop in a copper trace conductor of a PCB in order to detect an overload condition so that appropriate steps can be taken to avoid damage from being caused by the overload condition.
The closest known current sensing amplifier, shown in subsequently described Prior Art FIG. 1, requires complex circuitry and an associated method of temperature-compensating a voltage drop across the shunt resistor, by (1) sensing the voltage drop across the shunt resistor, (2) generating a signal representative of the shunt resistor temperature by means of a temperature sensor, and (3) externally digitizing and using that temperature signal to temperature-compensate an externally digitized representation of the sensed voltage drop across the shunt resistor by means of expensive and time-consuming digital techniques, for example by means of a microcontroller.
The closest prior art is believed to be shown in the published data sheet entitled "IA2410 High Voltage, High-Side Current Sense Amplifier" (date unknown), published by Integration Associates, Inc. of Mountain View, Calif. Prior Art FIG. 1 shows a functional block diagram of the current sense amplifier 2 in the above mentioned data sheet. Referring to Prior Art FIG. 1, the circuitry 1A includes the IA2410 current sense amplifier 2 connected to measure the voltage across a shunt resistor 6, which is illustrated as being on a printed circuit board 3. Printed circuit board 3 includes application circuitry 4 connected by a copper trace conductor 5 to one terminal of shunt resistor 6, which has a resistance RSHUNT. The other terminal of shunt resistor 6 is connected by copper trace conductor 5A to load circuitry 8, which can be located on or off printed circuit board 3. The above mentioned data sheet reference suggests that shunt resistor 6 could possibly be a section of the copper trace conductor 5,5A.
Conductor 5 in Prior Art FIG. 1 is coupled by a first gain resistor RG2 to the (+) input of an operational amplifier 9 in current sense amplifier 2, which also includes a variable current source 11, a temperature sensor 14, a switch 15, a buffer 16, and a control circuit 17. Conductor 5A is coupled by a second gain resistor RG1 to the (−) input of operational amplifier 9, the output of which is coupled by conductor 10 to the control input of variable current source 11. The upper terminal of variable current source 11 is connected to the (+) input of operational amplifier 9, and the lower terminal of variable current source 11 is coupled by means of a switch 20 to an output conductor 12 on which an output voltage is produced. Output conductor 12 is connected to one terminal of an output resistor 13 and also to the output of a buffer circuit 16. The input of buffer 16 is connected to one terminal of a switch 15, the other terminal of which is connected to the output of a temperature sensor 14.
The output of temperature sensor 14 and the output of the current source 11 representing the voltage across RSHUNT can be selectively applied to Vout conductor 12 by means of control circuit 17, switch 15, switch 20, and buffer circuit 16. The output of temperature sensor 14 thereby can be provided as an input to buffer circuit 16, the output of which can be digitized and used externally to temperature-compensate a digitized representation of the load current through RSHUNT. Control circuit 17 can control when each of the lower terminal of current source 11 and the output of temperature sensor 14 are operatively coupled, one at a time, to Vout conductor 12.
The use of current sensing amplifiers to accurately sense the voltage drop across a portion of a copper trace on a printed circuit board over a normal operating temperature range of −40 to +125 degrees Centigrade is problematic because this involves difficult trade-offs. Copper is a high-conductivity metal conductor rather than a resistive material, so a section of a conventional printed copper trace conductor would need to be very long (and perhaps configured in a serpentine pattern) in order to have a sufficiently high resistance to be usable as a shunt resistor for a conventional current sense amplifier. Use of a portion of a typical PCB copper trace conductor as a shunt resistor generally has been considered to be impractical because it would require a large and costly amount of PCB area.
Thus, there is an unmet need for an integrated circuit current sensing amplifier which makes it practical to provide very low cost, very accurate sensing of current flowing through a printed circuit board conductor.
There also is an unmet need for an integrated circuit current sensing amplifier which makes it practical to provide very low cost, very accurate sensing of current flowing through a printed circuit board conductor without requiring use of a temperature-sensing element.
There also is an unmet need for an integrated circuit current sensing amplifier which makes it practical to provide very low cost, very accurate sensing of a voltage developed across a portion of a printed circuit board conductor used as an external shunt resistance in response to a load current flowing through the printed circuit board conductor, wherein the current sensing amplifier provides simple, instant temperature compensation of the sensed voltage.
There also is an unmet need for an integrated circuit current-sensing amplifier which avoids the external digitizing and computation which the prior art requires to temperature-compensate the measured voltage across a shunt resistor.

Amplifier topology and method for connecting to printed circuit board traces used as shunt resistors


A liquid level sensor for standard bottles containing highly viscous materials such as gels so that the bottles may be inserted into an appliance to alert a user when the bottle is empty. The holder conveniently locates the bottle in the holder which includes insert molded contacts, wire harness and seal piercing mechanism. The bottle holder will universally fits into most appliances and machines. The invention enables the use of standard bottles are liquid reservoirs such that the bottle can be discarded when empty.

The use of devices to indicate the level of liquid within a tank or container is well known in the art. The need for knowing whether a liquid in a container is above or below a predetermined level is found in many very different situations. Typical of those situations where the liquid level must not be permitted to fall below a predetermined level are found in automobile radiators, windshield washer containers or oil in an engine crankcase. The situation where the level can be too high is also common such as found with a recreational vehicle holding tank. Applications for such equipment is also found in industry where frequently the liquid in question is extremely caustic as experienced with chemical reagent reservoirs which must be filled once the chemical has fallen below a particular amount in order to keep a process running.
A typical float-type of liquid level sensor is disclosed in U.S. Pat. No. 4,386,337, issued to Todd on May 31, 1983. This device is said to be useful for measuring the level of oil in an engine crankcase or transmission fluid in a reservoir. An electrically conductive float disposed within an encapsulator and movably responsive to the liquid level is provided. This movement is then determined. The problem associated with sludge buildup resulting in shorts bypassing the proper electrical pathways is not directly discussed. While Todd does suggest that by having his encapsulator with open upper and lower ends provides for self-flushing of debris, it is unclear how this can inhibit or stop the problems associated with residue formation, particularly as found in older systems.
The type of devices used to measure the liquid level also varies substantially. The use of floats, changes in capacitance, optical readers, weight measurements of the liquid are just a few examples of techniques that have been adopted to serve as an indicator of the surface level of a liquid. Some devices have attempted to utilize non-invasive measures, that is, a sensor that is outside of the liquid container.
Representative of this genre is U.S. Pat. No. 4,749,988, issued to Berman et al. on Jun. 7, 1988. The '988 Patent discloses the use of a pair of conductive band electrodes oriented in parallel so that the gap between the electrodes corresponds to the liquid surface level to be measured. The change in capacitance between the electrodes as the liquid level rises and falls serves as the indicator. While this device solves the corrosive problem found in processing industries using materials in liquid form, its use is limited to containment vessels which have sufficient outside room to put the sensor in place. Further, this type of sensor is expensive to manufacture in that it must be shaped to correspond to the particular shape of the vessel being used. Also, the thickness and material used for the vessel can also appreciably impact the accuracy and sensitivity of the device. Whether this will also solve the problem of residue buildup on the inside of he container is not know as Berman et al. does not discuss this issue.
U.S. Pat. No. 5,315,872, issued to Moser on May 31, 1994, discloses a liquid level sensor for an electrically conductive liquid. The device requires the use of an electrically conductive material for constructing the tank. Thus, many commonly used containers are unsuitable for use with this device without having substantial additional expense. A voltage source supplies an electrical charge to the tank walls, with ground potential being supplied to the liquid contained therein. The capacitance between the tank walls and liquid varies with the volume of liquid in the tank. The problem of false "full" readings is not discussed.
One of the potentially simplest and least expensive methods for the measurement of the level of a liquid is the use of an electrically conductive liquid as a part of a resistive circuit to ascertain the level. Representative of this genre is found in U.S. Pat. No. 4,277,773, issued to Blatnik on Jul. 7, 1981. This reference discloses a device for measuring the level of cooling liquid within a radiator. The radiator is grounded and an insulated probe is installed in the radiator and measures the level via interconnecting the sensor with the ground to obtain a conductivity measurement. A second sensor is provided to measure a hot liquid level in the same manner. While this device is simple and inexpensive to build, no protection against false "full" readings due to the accumulation of conductive sludge or other residue is disclosed or suggested.
U.S. Pat. No. 5,719,556, issued to Albin et al. on Feb. 17, 1998, discloses still another variation of a liquid level sensor that utilizes the measurement of resistance as an indicator. Albin et al. does recognize the problem of shorts from the sensor tip to ground via a conductive path through sludge. However, the inventors claim that merely insulting the sensing rods except at the tip will eliminate this problem. Further, their device is quite complicated and expensive requiring the use of alternating current, an oscillator, and filters as well as other circuitry in order to achieve their objectives.
Therefore, a simple conductive-type of liquid level sensor for highly conductive fluids such as dishwasher soap that is easy and inexpensive to manufacture, can be attached in a variety of tanks and containers without substantial modification of those tanks and prevent false "full" indications due residue buildup is not found in the prior art.

Disposable liquid level sensor having a virtual ring


A cable guiding-protecting chain comprises a plurality of chain members connected in series. Each chain member comprises two connection plates which face each other and are spaced apart from each other and a first link plate and a second link plate which each connect the two connection plates. The two connection plates, the first link plate and the second link plate cooperate to define a passing space penetrating from the front to the rear. Each connection plate has an inner link portion at a front segment thereof, an outer link portion at a rear segment thereof and an outer step portion. The outer link portion has a rear end edge which is arcuate in shape and a thinned portion which is close to the rear end edge and is thinned in thickness at a side adjacent to the passing space.

An existing cable guiding chain comprises a plurality of chain members, each chain member comprises a pair of inner connection plates and a pair of outer connection plates, a width between the two outer connection plates is more than a width between the two inner connection plates, the plurality of chain members are connected to each other in a manner that the two outer connection plates of the chain member at the front are respectively pivot to the two inner connection plates of the chain member at the rear so as to allow the plurality of chain members are connected in series, thereby defining an interior passing space through which a cable may pass and attaining the function of protecting the cable. Such a cable guiding chain is disclosed in Chinese patent application No. CN200810211522.0 (corresponding to Taiwanese patent application No. TW97134895), U.S. Pat. No. 7,387,046 (corresponding to Chinese patent application No. CN200410088034.7), and U.S. Pat. No. 6,029,437.
However, such a cable guiding chain has a problem in that, when every two chain members are pivot to each other, the two outer connection plates of the chain member at the front are respectively attached onto two outer sides of the two inner connection plates of the chain member at the rear, and the two outer connection plates of the chain member at the front are generally aligned with the two outer connection plates of the chain member at the rear respectively, if it is desired to disassemble the two chain members pivot to each other, a force is not easily applied to allow the outer connection plate of the chain member at the front to be disengaged from the inner connection plate of the chain member at the rear, and in turn the pivot relationship between the two chain members is not easily released, and during disassembling, the two chain members may also be easily damaged.


The present invention is drawn to devices and systems for allergen detection in a sample. The allergen detection system includes a sampler, a disposable analysis cartridge and a detection device with an optimized optical system. In some embodiments, the allergen detection utilizes aptamer nucleic acid molecules as detection agents. In some embodiments, the nucleic acids are conjugated to magnetic beads or solid surfaces such as glasses, microwells and microchips.

Allergy (e.g., food allergy) is a common medical condition that can have lethal consequences. It has been estimated that in the United States, up to 2 percent of adults and up to 8 percent of children, particularly those under three years of age, suffer from food allergies (about 15 million people), and this prevalence is believed to be increasing. Detection of allergens is not always straightforward and thus, a portable device that enables a person who has food allergy to test their food and determine accurately and immediately the allergen content will be of great benefit to provide for an informed decision on whether to consume or not.
Researchers have tried to develop suitable devices and methods to meet this need, such as those devices and systems disclosed in U.S. Pat. No. 5,824,554 to McKay; US Patent Application Pub. No.: 2008/0182339 and U.S. Pat. No. 8,617,903 to Jung et al.; US Patent Application Pub. No.: 2010/0210033 to Scott et al: U.S. Pat. No. 7,527,765 to Royds; U.S. Pat. No. 9,201,068 to Suni et al.; and U.S. Pat. No. 9,034,168 to Khattak and Sever, the contents of each of which are incorporated herein by reference in their entirety. There is still a need for improved molecule detection technologies. There is also a need for devices and systems that detect allergens of interest in less time, with high sensitivity and specificity, and with less technical expertise than the devices used today.
The present inventors have developed detection systems and devices using nucleic acid aptamer based signal polynucleotides (SPNs) as detection agents to detect an allergen in a test sample. The detection agents may be conjugated to magnetic beads and/or solid surfaces (e.g., a glass) to form allergen detection sensors; the sensors may then be integrated into an instrument for operating the detection assay, for example, a detection device as disclosed in the present invention. The aptamers that specifically bind to a target allergen may be those disclosed in commonly owned U.S. Provisional Application Ser. No. 62/418,984, filed on Nov. 8, 2016; and 62/435,106, filed on Dec. 16, 2016; 62/512,299 filed on May 30, 2017; and the PCT application No. PCT/US2017/060487 filed on Nov. 8, 2017; the contents of each of which are incorporated herein by reference in their entirety.
The inventors of the present invention further developed detection systems which include a separate sampler, disposable cartridges/vessels and a detection instrument, for fast and accurate detection of an allergen(s) in a sample using aptamer-based signal polynucleotides (SPNs). Particularly the aptamers and/or aptamer complement complexes are conjugated to magnetic beads and/or solid surfaces. The magnetic beads and solid surfaces coated with aptamer ligands are then used as detection sensors. The sensors may be integrated into the disposable cartridges of the present invention. They may also be used in other detection systems. Such devices may be used by consumers in non-clinical settings, for example in the home, in restaurants and school cafeteria.


A phase-separated elastomeric adhesive formulation and method of using the same are provided. The phase-separated elastomeric adhesive formulation does not require high temperatures in order to achieve bond strength. The material and methods are particularly advantageous for adhesively bonding both thick and irregularly shaped structures through which relatively low doses of electron-beam energy may not penetrate.

Adhesive bonding is a key process step in the fabrication or repair of many automotive and aircraft structural components. Adhesive bonding can eliminate the need for metal fasteners and their associated local stress concentrations. Most adhesive bonding for structural applications is initiated by application of heat. This is especially true in applications requiring rapid bonding, since adhesive curing is in general a temperature-dependent chemical reaction.
Some recent structural assemblies are composed of materials which melt at low temperatures, such as fiber-reinforced thermoplastic composites. Bonding such materials using heat-curable adhesives is difficult, because the high-temperature air typically used to heat the adhesive can warp or melt the composite. High temperature bonding of subassemblies composed of materials with different thermal expansion coefficients may cause residual thermal stress upon cooling the bonded assembly to room temperature. Composite assemblies with anisotropic coefficients of thermal expansion due to alignment of reinforcing fibers will warp when heated. Composites with complicated geometries, even those composed of isotropic materials, may warp upon heating, leading to debonding or cracking when cooled to room temperature. Some structural assemblies contain low density foam placed between composite shells to provide high stiffness and low weight. The foam can act as insulation material, preventing heat from reaching and curing adhesive bond lines.
In order to bond parts together successfully, particularly those with different coefficients of expansion, adhesive formulations must have a high degree of elastomeric character, which is typically not found in coating formulations. Therefore, in addition to being fully cured and solvent free, adhesives must meet requisite lap shear strength and extensibility values (i.e. high elongation to failure).
U.S. Pat. No. 2,688,133 issued to Brophy et al. on Feb. 2, 1954 discloses adhesives that are radiation curable.
U.S. Pat. No. 5,338,588 issued to Billiu on Aug. 16, 1994 discloses adhesives curable by electron-beam energy in a process for fabricating automotive composite assemblies. Radiation-curable adhesives, particularly electron-beam curable adhesives, are used in many such applications, since a cure may be effected with very little heating, and since electron-beams can penetrate through many materials, including foam, to reach the adhesive. Radiation-curable adhesives are also desirable because of their rapid rates of cure, compatibility with automatic dispensing equipment, and the environmental advantages of solvent-free systems. Generally, radiation-curable adhesives are cured using either ultraviolet energy in combination with a chemical photoinitiator, or electron-beam energy. However, most structural materials, including automotive and aircraft structural assemblies, require the deep penetrating ability of electron-beams as the materials they are formed from are opaque to ultraviolet light. Therefore, radiation-curable adhesives have not been useful in the assembly or repair of automotive or aircraft components, and they have been primarily limited to niche markets in the medical and electronics fields, due to high equipment costs as well as process and safety limitations. For example, the equipment used to generate electron- beams is considerably more costly than that required to generate ultraviolet light, and also requires radiation shielding for personnel safety, which typically consists of thick concrete walls and safety interlocks.
Typical accelerator and shielding costs and a description of the cost tradeoffs are given in the article by Goodman, et. al., "Advanced Electron-beam Curing Systems and Recent Composite Armored Vehicle Results," (Proceedings of The Journal of the Society for the Advancement of Material and Process Engineering (SAMPE) Vol.42, 1997 p.515-525). The relationships between electron-beam dose, energy, current and throughput are given in the review by Cleland ("High Power Electron Accelerators for Industrial Radiation Processing, in Radiation Processing of Polymers," A. Singh and J. Silverman, eds., Oxford University Press, N.Y. 1992, p.34-38).
In electron-beam curing, the system throughput, which is the amount of adhesively bonded material processed per unit time, depends on the rate at which a minimum dose can be delivered to the adhesive bond. Electrons penetrate through a depth of material proportional to their initial energy and inversely proportional to the material density. For beam energies exceeding the threshold needed to penetrate to the adhesive bond, the dose rate is nearly independent of energy and depends only on beam current. As described in the 1997 Proceedings of SAMPE article by Goodman, et. al., the cost of electron accelerator systems are primarily a function of accelerator power, (the product of electron gun voltage and current) and increase rapidly at powers above 10 kW. A process which can substitute lower power electron-beam equipment where higher power equipment was previously thought to be required, will significantly reduce equipment capital costs.
Conversely, if two electron-beam systems possess equal power, and both exceed the minimum energy to penetrate to the adhesive bond, the system with lower beam energy is more efficient, and will have a higher throughput. This is because less beam penetrates beyond the adhesive interface and is wasted in heating the interior of the part. Thus, a process which can substitute lower energy equipment of a given power, where higher energy equipment of equal power was thought to be required, will provide greater throughput, and therefore processing cost advantages.
As shown in the 1997 Proceedings of SAMPE article by Goodman et. al., the required shielding thickness (and therefore facility cost) increases with increasing electron-beam energy. Significant facility cost savings can be made if a process can substitute lower energy electron-beam equipment where higher energy equipment was previously thought to be required. Such a facility will also require less area, or allow larger parts to be processed in the same area, since a smaller fraction of the available space is taken up by the shielding.
Woods et al. disclose dual-cure adhesives that are rendered thermally curable by incorporating a thermal cure initiator capable of producing free radicals on heating, such as, for example, peroxides, azo compounds and disulfides. Curing of the adhesives typically requires exposure to radiation followed by heating in an oven or by directed heat lamps, typically to temperatures above 60.degree. C., and often above 100.degree. C., in order to activate the thermal cure initiators.
In "Structure-Property Behavior of Segmented Polyether-MDI-Butanediol Based Urethanes: Effect of Composition Ratio," by S. Abrouzahr et. al. in Polymer 23, p. 1077 (1982), polyurethanes are disclosed in which the hard pahse (with a T.sub.g above ambient) and the soft phase (with a T.sub.g below ambient) are well-formed regions which contribute to the elastomeric character at temperatures between the two T.sub.g s.
Radiation-sensitive phase-separated elastomeric adhesives are advantageous because they stretch when required to do so and return to their original dimensions upon release of a force. That is, mechanical hysteresis is minimal at appropriate extensions in these materials. In order to provide high elongation to failure values that are required for elastomeric adhesives, phase-separated polyurethane adhesives require well-defined domain structures including both a soft phase and a hard phase. The soft phase must be capable of rubbery behavior between the glass transition temperatures of the two phases, and not lead to extensive phase mixing on extension before break. In order to have soft and hard phases, polymer chain segments long enough to separate into well ordered regions must be present, both in the soft phase and in the hard phase, which typically requires a polyol having a molecular weight of at least 600. Polyols of insufficient molecular weight between cross-linking reactive groups will not be able to phase separate and behave elastomerically.
U.S. Pat. No. 4,342,793 issued to Skinner et al. on Aug. 3, 1982 disclose dual-cure coating compositions that are radiation and thermally curable, and include a radiation-sensitive reactive diluent, a chemical photoinitiator, and a thermally curable portion, reacted together to form an interpenetrating network. The thermal curing is effected with heat generated by a urethane reaction between an isocyanate and a saturated polyol. Both simultaneous and sequentially polymerized networks are present in the adhesive.
Therefore, a need exists for a radiation-curable phase-separated elastomeric adhesive that may be cured at room temperature.

Phase-separated dual-cure elastomeric adhesive formulations and methods of using the same


A temperature comparison module generates a temperature difference between an engine coolant temperature and a radiator coolant temperature. An energy determination module determines an energy value corresponding to heat energy generated by an engine. The heat energy increases at least one of the engine coolant temperature and the radiator coolant temperature. A diagnostic module generates a comparison of the temperature difference and the energy value and determines a status of a thermostat associated with the engine based on the comparison.

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An engine combusts a mixture of air and fuel in a combustion process to produce a drive torque. During the combustion process, the engine converts chemical potential energy of the air/fuel mixture into kinetic energy and heat energy. A portion of the heat energy may be transferred to a coolant mass (m) circulating through the engine.
The heat energy may cause a coolant temperature of the coolant mass (m) to increase. The coolant temperature may be measured by an engine coolant temperature (ECT) sensor at a location inside the engine. The ECT sensor sends the ECT to an engine control module (ECM).
A thermostat may regulate the amount of the coolant mass (m) circulating through the engine. The thermostat is a thermostatic valve that opens when the coolant temperature reaches a thermostat opening temperature and closes when the coolant temperature is below the opening temperature. While the thermostat is closed, the coolant mass (m) circulating through the engine is smaller than when the thermostat is open.
Normally when the coolant temperature is below the opening temperature, the thermostat is closed so that the coolant mass (m) circulating through the engine is smaller. The heat energy transfers to the smaller coolant mass (m) and increases the ECT to an operating range. The operating range may be a coolant temperature range of approximately 180° F. to 200° F. Once the ECT is within the operating range, the thermostat may subsequently open to increase the amount of the coolant mass (m) circulating through the engine and regulate the coolant temperature.
A stuck open thermostat occurs when the thermostat remains stuck open regardless of the coolant temperature. The stuck open thermostat may delay or prevent the ECT from increasing to the operating range by allowing the coolant mass (m) circulating through the engine to be larger. The heat energy is transferred to a larger coolant mass, which results in a slower coolant temperature increase. The coolant temperature is therefore below the operating range for a longer period than when the coolant mass (m) is smaller.
While the coolant temperature is below the operating range, lubricating liquids inside the engine may be less effective and components of the engine may wear out faster. The combustion process may be less efficient and fuel vaporization may be less effective. The exhaust emissions may emit more pollutants. When the coolant temperature is in the operating range, the engine operates in more favorable conditions for fuel vaporization, engine lubrication, and exhaust emissions.
A coolant temperature model may be used to determine when the thermostat is stuck open. For example, a modeled ECT may be compared to the sensed ECT to determine when the thermostat is stuck open. When the difference between the modeled ECT and the sensed ECT is large enough, the thermostat may be stuck open. The model may be inaccurate and may require a lengthy period to diagnose the stuck open thermostat. In addition, multiple coolant temperature models may be required for multiple engines and cooling systems.

Engine cooling system diagnostic for applications with two coolant sensors


A device for checking decimal data includes a command analyzing circuit which analyzes the content of a main storage command register and a data register for storing data read from a main storage unit via a system bus, a decimal data format checking circuit for checking the decimal format of the read-out data by the output of the command analyzing circuit, a check result register for storing the check result, an arithmetic operation unit into which data necessary for the arithmetic operation are entered from the data register and the decimal format check result from the check result register for arithmetic operation. Therefore, the speed of processing is increased, since data can be loaded while the decimal data format is also checked.

The present invention relates to a device for checking decimal data in a data processing system.
A conventional decimal data checking device, as shown in FIG. 1, comprises a main storage command register 1 for storing various commands such, for example, as a read/write command or the like, a command analyzing circuit 2 for analyzing these commands, a data register 4 for storing the data read from the main storage unit and a circuit 3 for checking the decimal format of the data supplied from the data register 4. In the known circuit, the command from the main storage command register 1 is analyzed in the command analyzing circuit 2 and the data necessary for a desirable arithmetic operation are sent via a system bus 7 to the data register 4 .
Upon execution of a desired arithmetic operation, necessary data are read out from the data register 4 to check in the decimal data format checking circuit 3. If no format error is found in the checking operation, then the data are used for the arithmetic operation conducted in the arithmetic operation unit 5 using those data. However, if there is any format error or the like in the data, then, as an exceptional processing, the data are read again into the data register 4 via the system bus 7.
As described above, in the conventional decimal data checking device, the data read from the main storage unit is read into the data register once before the necessary data is checked in the decimal data format checking circuit 3. If there is no error in it, then an arithmetic operation is carried out in the arithmetic operation unit 5 and, if yes, then it is not carried out. In consequence, when the arithmetic operation is done, the quality of the data format which is read from the data register 4 cannot be determined. This means that, prior to the arithmetic operation, it is necessary to arithmetically operate after it is confirmed in the decimal data format checking circuit 3 that there is no error in the decimal data format checking circuit 3, which can delay the processing speed until the arithmetic operation is actually conducted after the data necessary for the arithmetic operation is read out.


A detachable seat for a vehicle, includes a seat cushion, a seat leg mechanism for supporting the seat cushion, the seat leg mechanism including a base member on which the seat cushion is carried, and first and second spaced apart leg members pivotally connected to the base member, a seat back pivotally mounted to the base member of the seat leg mechanism, a first cooperating mechanism on the first and second leg members and a vehicle floor for causing the seat to be releasably locked with the vehicle floor, and a second cooperating mechanism on the base member and the seat cushion for causing the seat cushion to be removably or detachably mounted with respect to the base member.

1. Field of the Invention
This invention relates to a detachable seat for a vehicle, which facilitates obtaining of a space for any burdens and longitudinal articles and a walk-through space in the vehicle and, more particularly, to a detachable seat which is designed to be foldable or collapsible.
2. Description of the Related Art
Japanese Patent Application laid open under Provisionary Publication No. 2001-301496 discloses three seats for a vehicle, which are arranged side by side and designed in order to facilitate obtaining of a walk-through space in the vehicle. The seats comprise first and second seats, and a center seat arranged between the first and second seats. The center seat includes seat leg means slidably supported to a rail mechanism mounted to a vehicle floor and movable forward and rearward in the vehicle, and a seat cushion pivotally supported to a side of a seat cushion of one of the first and second seats so as to be vertically pivoted and adapted to be carried on the seat leg means and releasably secured with respect to the seat leg means during use of the center seat.
The seat leg means is provided with a striker. The seat cushion is provided with a striker lock. The seat cushion is releasably secured to the seat leg means by causing the striker lock of the seat cushion to be engaged with the striker of the seat leg means.
In the conventional center seat constructed as described above, when it is necessary to obtain a walk-through space in the vehicle, releasing of the seat cushion of the center seat from the seat leg means is carried out by causing the striker lock of the seat cushion to be disengaged from the striker of the seat leg means, whereby the seat cushion is released from the seat leg means. In a condition where the seat cushion of the center seat is released from the seat leg means and pivoted upward by a passenger's hand, when forward or rearward movement of the seat leg means is performed while causing the seat cushion to be released from the passenger's hand, the seat cushion of the center seat is pivoted downward by gravity. Thus, the seat cushion of the center seat is vertically accommodated in a space around the side of the seat cushion of the one of the first and second seats to which the seat cushion of the center seat is pivotally supported, whereby the walk-through space can be provided between the first and second seats. In this condition, the center seat is unavailable.
In the conventional center seat, the seat cushion of the center seat is vertically accommodated in the space around the side of the seat cushion of the one of the first and second seats, so that the walk-through space is provided between the first and second seats as discussed above. However, when the walk-through space is provided between the first and second seats, the seat leg means is located forward or rearward from the first and second seats, so that the seat leg means will interfere with widely utilizing of the space between the first and second seats as a storage space for any longitudinal articles, e.g. umbrellas, and a walk-through space.
Japanese Patent No. 3,356,970 discloses vehicle seats that are designed to be detachable from a vehicle floor in order to facilitate obtaining of a storage space for any longitudinal articles and a walk-through space in a vehicle. In the vehicle seats, there are problems of how each of the detached vehicle seats should be folded or collapsed into a single compact configuration after use of the vehicle seats, of how each of the detached vehicle seats should be easily returned to a usable condition when it is to be used, and of how each of the detached vehicle seats should be stably set on the vehicle floor when it is to be used.


A process for production of carboxylic acid aryl esters which comprises reacting a carboxylic acid having at least one carboxyl group with a di- or tri-aryl phosphite compound, in the presence of a basic compound and/or water. The carboxylic acid aryl esters can also be produced by reacting a carboxylic acid or a basic salt thereof with a diaryl phosphite compound.

1. Field of the Invention
The present invention relates to a process for production of carboxylic acid aryl esters. More specifically, the invention relates to a process for production of carboxylic acid aryl esters by a novel reaction not known in the prior art.
2. Description of the Related Art
Aryl esterification of carboxylic acids has conventionally been accomplished by a dehydration reaction between carboxylic acids and phenols, by a method such as (1) using a mineral acid as the catalyst or (2) using a dehydrating agent at an equivalent amount or greater. There is also known a method whereby (3) a carboxylic acid halide and a phenol are reacted to obtain a carboxylic acid aryl ester.
The method of (1) can be applied for production of alkyl esters from alkyl alcohols, but has a drawback in that, with phenols, either no reaction occurs or the reaction yield is very poor.
An example of the method of (2) is described in xe2x80x9cOrganic Compound Synthesesxe2x80x9d (Yuki Kagobutsu Goseiho, by the Society of Synthetic Organic Chemistry, Japan) whereby polyphosphoric acid is used as the dehydrating agent, but since this requires use of the polyphosphoric acid in a large amount, the cost is high and waste water treatment also poses a problem. Japanese Unexamined Patent Publication No. 5-84507 discloses the use of dicyclohexylcarbodiimide as a dehydrating agent, but in this case the dehydrating agent is expensive and a problem is posed in economical terms.
For method (3), a number of documents describe halogenation of a carboxylic acid using a halogen compound such as PCl3, POCl3, PCl5 or SOCl2 followed by reaction with a phenol, but the method involves a complex production process, as a two-stage reaction, and is therefore not a preferred choice.
It is an object of the present invention to overcome the problems associated with the prior art by providing a process for production of carboxylic acid aryl esters which is very simple, easy and inexpensive.
In order to achieve this object, the present invention provides a process for production of carboxylic acid aryl esters which comprises reacting a carboxylic acid having at least one carboxyl group with a di- or tri-aryl phosphite compound represented by the following general formula (1):
where each R independently represents a hydrogen atom, halogen or alkyl group, m is 2 or 3 and n is 1, 2, or 3, and when there exist a plurality of halogen and/or an alkyl groups as R, they may be the same or different, in the presence of a basic compound and/or water.
The invention further provides a process for production of carboxylic acid aryl esters which comprises reacting a basic salt of a carboxylic acid having at least one carboxyl group with a diaryl phosphite compound represented by the following general formula (2):
where each R independently represents a hydrogen atom, halogen or alkyl group, n is 1, 2, or 3, and when there exist a plurality of halogen and/or alkyl groups as R, they may be the same or different.
The invention still further provides a process for production of carboxylic acid aryl esters which comprises reacting a carboxylic acid having at least one carboxyl group with a diaryl phosphite compound represented by general formula (2) above.
According to the process of the invention, the reaction may be carried out with the di- or tri-aryl phosphite compound of general formula (1) used in an amount at least equivalent with respect to the carboxyl groups of the carboxylic acid. The reaction is commonly carried out with heating or stirring, and if necessary using a solvent, but the process of the invention is in no way limited to these reaction conditions. The esterification rate will differ slightly depending on the type of carboxylic acid compound used as the starting material, but an esterification rate of 80% or greater, and in most cases 90% or greater, can be easily achieved for a variety of compounds.
Any of various ordinary methods may be employed to recover the desired aryl ester from the reaction system after completion of the reaction. For example, if the reaction product is distillable, it may be distilled off and the product recovered. Alternatively, if the reaction product crystallizes, it may be crystallized out or else dissolved in an appropriate solvent and then cooled to crystallization, and the product recovered.
It has been found that addition of basic compounds or a small amount of water during the process of the invention will promote the reaction. Examples of such basic compounds include alkali metal or alkali earth metal hydroxides, oxides, carbonates and the like.
In the process of the invention, it is believed that when a reaction between the carboxylic acid and a triaryl phosphite compound of general formula (1), where m is 3, is carried out in the presence of a basic compound, a basic salt of the carboxylic acid is produced first while a phenol compound corresponding to a diaryl phosphite compound of general formula (1) where m is 2 is also produced, and then the carboxylic acid basic salt and diaryl phosphite compound in turn react to produce the corresponding carboxylic acid aryl ester and corresponding arylphosphonic acid basic salt. According to the invention, therefore, the target carboxylic acid aryl ester can also be produced by reaction of the carboxylic acid basic salt and diaryl phosphite compound of general formula (1) where m is 2, instead of reaction of the carboxylic acid and triaryl phosphite compound of general formula (1) where m is 3 in the presence of a basic compound. Consequently, the present invention also encompasses a process for production of carboxylic acid aryl esters which comprises reacting the aforementioned carboxylic acid basic salts with diaryl phosphite compounds represented by general formula (2).
On the other hand, it is believed that when the aforementioned carboxylic acid and triaryl phosphite compound of general formula (1), where m is 3, are reacted in the presence of water in the process of the invention, the triaryl phosphite compound first hydrolyzes to produce a diaryl phosphite compound of general formula (1) where m is 2 and the corresponding phenol compound, and then the resulting diaryl phosphite compound and the carboxylic acid react to produce the corresponding carboxylic acid aryl ester and the corresponding arylphosphonic acid. According to the invention, therefore, the target carboxylic acid aryl ester can also be produced by reaction of the carboxylic acid and diaryl phosphite compound of general formula (1) where m is 2, instead of reaction of the carboxylic acid and triaryl phosphite compound of general formula (1) where m is 3 in the presence of water. Consequently, the present invention also encompasses a process for the production of carboxylic acid aryl esters which comprises reacting the aforementioned carboxylic acid with diaryl phosphite compounds represented by general formula (2).

Process for production of carboxylic acid aryl esters


A bandgap voltage reference circuit includes a low temperature coefficient of resistance (TCR) tail resistor connected in series with a high TCR tail resistor, and a low TCR correction resistor connected in parallel with the high TCR resistor. The ratio of resistance values for the parallel resistors is selected to produce a correction voltage that essentially cancels a Tln(T) output deviation from temperature linearity, where T is absolute temperature. Matching voltage-temperature characteristics are obtained by selecting a resistor ratio at which the rate of change in the circuit's output voltage, both with and without the parallel resistors, is substantially zero at approximately the same temperature. While the shape of the compensation voltage-temperature curve is determined by the resistor ratio, it is scaled to the magnitude of the Tln(T) deviation by an appropriate selection of absolute resistor values. The correction resistor is preferably a trimmable thin film element.

1. Field of the Invention
This invention relates to bandgap voltage reference circuits, and more particularly to such circuits in which an attempt is made to correct for a Tln(T) deviation from linearity in the output voltage.
2. Description of the Prior Art
Bandgap reference circuits have been developed to provide a stable voltage supply that is insensitive to temperature variations over a wide temperature range. These circuits operate on the principle of compensating the negative temperature drift of a bipolar transistor's base-emitter voltage (V.sub.be) with the positive temperature coefficient of the thermal voltage V.sub.T, which is equal to kT/q, where k is Boltzmann's constant, T is the absolute temperature in degrees Kelvin and q is the electronic charge. A known negative temperature drift due to V.sub.be is first generated. A positive temperature drift due to the thermal voltage is then produced, and is scaled and subtracted from the negative temperature drift to obtain a nominally zero temperature dependence. Numerous variations in the bandgap reference circuitry have been designed, and are discussed for example in Grebene, Bipolar and MOS Analog Integrated Circuit Design, John Wiley & Sons, 1984, pages 206-209.
Although the output of a bandgap voltage cell is ideally independent of temperature, or at least varies linearally with temperature, the outputs of prior cells have been found to include a term that varies with Tln(T), where 1n is the natural logarithm function. Such an output deviation is shown in FIG. 1, in which the bandgap voltage output (V.sub.bg) increases from a value of about 1.2408 volts at -50.degree. C. to about 1.2444 volts at about 45.degree. C., and then returns back to about 1.2408 volts at 150.degree. C. This output deviation is not symmetrical; its peak is skewed about 5.degree. C. below the midpoint of the temperature range.
It is difficult to precisely compensate for the Tln(T) deviation electronically, so simpler approximations have been used. One such circuit is shown in FIG. 2, and is described in U.S. Pat. No. 4,808,908 to Lewis et al., assigned to Analog Devices, Inc., the assignee of the present invention. The circuit includes bipolar npn transistors Q1 and Q2, with the emitter area of Q2 scaled larger than that of Q1 by a factor A. The emitters of Q1 and Q2 are connected together through a resistor R1 that has a relatively low temperature coefficient of resistance (TCR). A second relatively low TCR resistor R2 is connected in series with a relatively high TCR resistor R3 between the R1/Q1 emitter junction and a negative (or ground) voltage bus V-. Q1 and Q2 are provided with collector currents with a constant ratio between the current magnitudes, such as by connecting their collectors respectively to the inverting and non-inverting inputs of an operational amplifier. R1 and R2 are preferably implemented as thin film resistors, with TCRs on the order of 30 ppm (parts per million)/.degree.C.; such low TCRs may be considered to be negligibly small for purposes of the invention. R3 is preferably a diffused resistor having a TCR of typically 1,500-2,000 ppm/.degree.C.
The output voltage V.sub.bg is equal to the sum of V.sub.be for Q1 and the voltage drops across R2 and R3. In the absence of R3, the voltage across R2 can be determined by considering the voltage across R1. This is equal to the difference in V.sub.be for Q1 and Q2; since the emitter of Q2 is larger than the emitter of Q1 but both transistors may carry equal currents, the emitter current density of Q2 will be less than for Q1 and Q2 will accordingly exhibit a smaller V.sub.be. The V.sub.be differential between Q1 and Q2 will have the form V.sub.T ln (Id1/Id2)=V.sub.T ln(A), where I1 and I2 are the absolute emitter currents, and Id1 and Id2 are the emitter current densities of Q1 and Q2, respectively. Since I1 is preferably equal to I2, the current through R2 will be twice the current through R1, so that the voltage across R2 will have the form (2R1/R2)V.sub.T ln(A). Still ignoring R3, the described circuit will exhibit the Tln(T) output deviation mentioned above.
The addition of high TCR resistor R3 approximates a Tln(T) output voltage compensation by producing a square law (T.sup.2) term that is added to V.sub.bg. Since the tail current through R2 is proportional to temperature anyway, adding a significant temperature coefficient by means of the high TCR tail resistor R3 yields a voltage across this resistance that is proportional to T.sup.2. Combining this square law voltage with the voltage across R2 and V.sub.be for Q1 approximately cancels the effect of the Tln(T) deviation.
R3 is preferably a diffused resistor, which is not subject to trimming. However, the resistance values of thin film resistors R1 and R2 can be conveniently adjusted by laser trimming to minimize the first and second derivatives of the bandgap cell output as a function of temperature.
Unfortunately, the square law voltage compensation produced by the FIG. 2 circuit is perfectly symmetrical, as opposed to the skewed parabolic shape of the Tln(T) deviation that actually characterizes the bandgap cell. Thus, the voltage correction that can be achieved with the FIG. 2 circuit is limited. FIG. 3 compares the Tln(T) and T.sup.2 functions, scaled to a normalized value of the correction voltage V.sub.corr. The resulting variation in the net V.sub.bg, plotted on a normalized scale in which zero is the nominal V.sub.bg, is illustrated in FIG. 4. This is a sideways S-shaped curve that exhibits a significant residual temperature coefficient in both the upper and lower portions of the temperature range.

Bandgap voltage reference circuit and method with low TCR resistor in parallel with high TCR and in series with low TCR portions of tail resistor


An optical transmitter with an external modulator includes a light-emitting unit emitting a continuous wave light, a modulation unit modulating the continuous wave light in accordance with an electric signal, a first terminal applying a first positive voltage to a cathode of the light-emitting unit and a cathode of the modulation unit, a second terminal applying a second positive voltage of a constant value to an anode of the light-emitting unit, and a third terminal applying a third positive voltage with the electric signal to an anode of the modulation unit. The second positive voltage is set to a value higher than the first positive voltage, and the third positive voltage is set to a value lower than the first positive voltage.

1. Field of the Invention
The present invention relates to an optical transmitter with an external modulator, an optical transceiver including the optical transmitter with the external modulator, and methods of driving the same, and more particularly, to an optical transmitter with an electro-absorption optical modulator serving as an external modulator, an optical transceiver including the optical transmitter with the electro-absorption optical modulator, and methods of driving the same.
2. Description of the Related Art
In optical communications, an optical transceiver is a key device serving as an interface between an electric signal and an optical signal. The optical transceiver includes an optical transmitter performing electrical-optical conversion and an optical receiver performing optical-electrical conversion. In order to drive and control the optical transmitter and the optical receiver, the optical transceiver generally further includes a microcomputer, a driver circuit, a power supply circuit, and a temperature adjusting circuit.
In recent years, it has been requested that a transmission distance and a communication capacity are increased with the rapid expansion of fields to which optical communications are applied. Therefore, in order to satisfy the requirements of chromatic dispersion and spectral accuracy on long-haul transmission, dense wavelength division multiplexing (DWDM) transmission, or the like, an external modulating method is used for many structures of the optical transmitter installed in the optical transceiver. An electro-absorption optical modulator (EAM) which is easily integrally formed with a semiconductor laser has been known as one of means for realizing the external modulating method. An optical transmitter including the EAM is disclosed in Japanese Patent Application Laid-open No. Hei 09-179079 (patent family U.S. Pat. No. 5,917,637). A modulator integrated laser diode (MI-LD) serving as the optical transmitter includes a laser diode (LD) having an active layer emitting light and an EAM having an absorption layer absorbing the light to modulate the light. The LD and the EAM are integrally formed with each other. In the MI-LD, the active layer of the LD is directly connected with the absorption layer of the EAM, so the light emitted from the active layer of the LD is efficiently introduced into the absorption layer of the EAM. Thus, the MI-LD has an advantage in that a high-efficiency optical transmitter with an external modulator is obtained. The MI-LD can be formed using a single semiconductor chip, so the MI-LD has an advantage in that a reduction in size can be achieved by integration.
However, in order to drive the MI-LD described in Japanese Patent Application Laid-open No. Hei 09-179079, it is necessary to apply a forward bias voltage to LD side and to apply a backward bias voltage to the EAM side. That is, it is necessary to apply a positive applied voltage to an LD side electrode relative to a grounded common electrode for the LD and the EAM and to apply a negative applied voltage to an EAM side electrode relative thereto. Therefore, in order to drive the MI-LD, two different power supplies, namely, positive and negative power supplies are required. Furthermore, the use of the negative voltage power supply may cause generation of power supply noise and deterioration in characteristic of the optical transceiver which are caused by the negative voltage power supply. It is necessary to draw power supply wirings for the negative voltage power supply and to use parts for the negative voltage power supply. Thus, the MI-LD has a fear of reducing the general versatility in a case where the optical transmitter is installed in an apparatus or in use environments.

Optical transmitter with external modulator, optical transceiver including optical transmitter with external modulator, and methods of driving the same


A pliable centrifuge tube array includes a number of tubes having collars which are interconnected by flexible tethers that permit the tubes to diverge when they are placed into holes in a centrifuge rotor. The tubes have a noncircular cross section providing grooves or apexes in which pellets of dense material preferentially collect. In some embodiments, the tethers or tubes have a latching mechanism such as mating projections and sockets which, when engaged, hold the tubes together in close array. The tubes may have individual lids which can be opened and closed simultaneously with a prying tool specially designed for the purpose.

This invention relates to the arts of medicine and chemistry and more particularly to a pliable centrifuge tube array.
A centrifuge is a device used to separate constituents of a sample according to density by generating artificial high "gravity" using centrifugal force. A typical centrifuge has a rotor which is spun at high speed by a motor. The rotor has recesses or slots ("wells") for receiving tubes containing samples to be separated. In rotors where the wells angle downward and outward, the dense material settles out toward one the side of the tube, near the bottom, forming what is known as a "pellet". It is best that the pellet be to one side, so that an aspirating pipette inserted along the opposite side will be sure to avoid interfering with the pellet.
Many current laboratory procedures involve repetitive centrifugation and resuspension in solution of individual samples of cells or extracts of cells: DNA, RNA, proteins, lipids, etc. The samples are spun in a centrifuge, then the supernatant liquid is aspirated off the pellet, another solution is added to the tubes, and the samples are spun again. This procedure may be repeated several times.
To improve processing speed, linear arrays of plastic tubes have been molded with the tubes interconnected along their sides. The axes of the tubes in such an array are parallel. Such tube arrays are convenient to handle, and by providing a constant predetermined centerline spacing, work well with automatic tube filling and sampling equipment such as multi-channel pipettes.
Parallel tube arrays have the problem that, when they are placed in a centrifuge, only one of the tubes can be located in a radial plane of the rotor. For any tube not in a radial plane, the "downward" direction in which the heavy constituents move is toward one side of the tube. Thus, the pellets of dense material which develop in such tubes wind up at various spots on the sides of the tubes. That is, the pellets are splayed away from each other in their location. The variation in pellet location makes it difficult to avoid consistently the pellets when aspirating liquid from the tubes. This problem is worse in an automated system where the pellet must be located by referring to a landmark on the tube.
In order for each tube to lie, properly, in a radial plane of the centrifuge rotor, and to get consistent pellet placement, the tubes must be able to diverge or splay outward.
Another disadvantage of conventional micro-centrifuge tube is that it has only a small outer surface on which the tube may be marked. Typically, the experimenter applies a number, and matches that number to a description in a notebook. This system is cumbersome: sometimes there is confusion as to what experiment the number refers to, especially after the tubes have been in storage for a while. It would be better to maintain tubes in united arrays which could be identified as a unit, and to provide a tube rack which could be marked upon as well.


A process and apparatus for manufacturing wood chips as raw material in the production of mechanical pulp in order to reduce energy consumption. The process includes irreversibly deforming a plurality of fibers of at least one piece of wood in a direction perpendicular to the longitudinal axis of the fibers. The wood fibers include summerwood fibers. The irreversible deformation is accomplished through mechanical treatment. The apparatus used includes one or several tools arranged so that the forces created during the process act in a direction substantially perpendicular to the longitudinal axis of the fibers so as to irreversibly deform the fibers across the grain.

Traditionally, the raw fibre material used in the production of mechanical pulp has been subjected to a two step mechanical treatment process. The first step is known as "chipping" and includes disintegration of the wood. The second step is referred to as "refining" and involves separating the fibres and increasing their flexibility in one or two refiners. Many of the currently used processes for chipping were developed for the production of chemical pulp, before the introduction of mechanical pulp in the pulp and paper industry. In the production of chemical pulp, the fibre is attacked during chemical cooking (defibration) and is susceptible to weakening and shortening at the sites that have been mechanically deformed. As a result, fibre deformation is unwanted during the production of chemical pulp and therefore minimized.
Apparatuses and processes for chipping have tried to achieve chips of uniform size with minimal fibre deformation. For example, U.S. Pat. No. 3,304,970 describes a new way to produce wafers to avoid the deformation encountered in conventional chipping. The damage to the fibres, e.g. bruising which occurs in chipping is thought to reduce the quality of the wood chips.
Other patent publications concerning chips both for production of paper and board, highlight the benefit of splitting the raw wood material in a direction parallel to the longitudinal axis of the fibres as being less severe to the fibres. For example, U.S. Pat. No. 3,407,854 describes it as preferred to produce chips that are not compressed or damaged.
SE 463 295 concerns the adjustment of the cutting tools in chipping, expressly to avoid the risk of forming longitudinal defects, caused by the pressure, in the fibre walls.
While the industry has increased its production of mechanical pulp, the traditional methods of chipping have nevertheless remained largely unchanged. With some variations for different methods of chipping, the thickness of the chip has been on the order of 3 to 7 mm. These chips have been fed into refiners of different construction for exposing and flexibilizing the fibres. The refiners have been developed for, and adjusted to, the type of chip conventionally used in the production of chemical pulp. The energy consumption during refining is considerable. Additionally, the refining step is a very non-selective way of treating the fibres. During more prolonged refining an unwanted fibre shortening takes place. In spite of this, refining has to be performed up to a certain degree to guarantee that the main part of the fibres is exposed and flexibilized to a sufficient extent.
One special quality of the raw fibre material has gained larger importance in mechanical pulping in recent years. This is that the wood fibres, dividable as they are into fibres with thin walls and thick walls, so-called springwood fibres and summerwood fibres, respectively, have very different mechanical properties. The thick-walled fibres in the summerwood are resistant to strong loads in a direction perpendicular to their length. Whereas, the springwood fibres are more easily deformed by these strong loads applied in the same direction. The summerwood fibre can resist loads that are 10 times greater than the loads that the springwood fibre can resist. All non-selective treatment of fibres leads to more or less unwanted results. For example, refining to the extent needed to flexibilize the summerwood fibres, reduces the springwood fibres in a large extent to fines, which leads to inferior dewatering properties of the pulp and thus, weaker paper. With less extensive treatment, the summerwood fibres retain unreduced stiffness, which leads to unevenness in the paper surface and weaker paper.
The length and anal strength of the wood fibres (both tensile strength and compression strength) should be conserved to as large an extent as possible. The transversal strength of the fibre should nevertheless be reduced, making the fibre more easily collapsible. The transversal strength of the fibres can be reduced and the fibres made flatter, i.e. collapsed, by irreversibly deforming them with a cutting tool. A collapsed fibre has a substantially lower bending stiffness. The lower bending stiffness makes the fibre more easily adaptable to surrounding fibres. The number of contact points between the easily adaptable fibres in the paper thus increases and so does the density of the paper. A collapsed fibre is also flatter, which increases the area of its contact surface with other fibres.
Attempts with rolling the chips, i.e. subjecting them to forces perpendicular to the fibre's length direction, in order to reduce the energy consumption in the production of mechanical pulp, has shown little effect. This is due to the fact that the weaker fibres in the springwood are compressed first and function as a deformation buffer protecting the stronger fibres of the summerwood.


A system (10) for generating a chlorine-containing compound includes an anodic chamber (12), a cathodic chamber (20), and a brine chamber (30). The anodic chamber (12) includes an anodic electrode (14) and the cathodic chamber (20) includes a cathodic electrode (22). A membrane (28) separates the anodic and cathodic chambers (12), (20). The brine chamber (30) includes an anodic electrode (32) and a cathodic electrode (34). Concentration and type of the chlorine-containing compound can be selectively and consistently controlled by the system (10) in real time.

The subject invention generally relates to a system for generating a chlorine-containing compound and, more specifically, to a system and method for generating a chlorine-containing compound for disinfecting and/or sanitizing a substrate.
Chlorine-containing compounds are well known in the art and are utilized in various industries due to their unique physical properties. Most commonly, chlorine-containing compounds are utilized in cleaning applications. For example, hospitals, restaurants, and even households often employ various chlorine-containing compounds for disinfecting, bleaching, whitening, deodorizing, and/or otherwise cleaning substrates.
For example, one chlorine-containing compound is sodium hypochlorite (NaClO), which is utilized as a powerful disinfecting agent and/or a bleaching agent. Sodium hypochlorite is commonly referred to as bleach when disposed in water to form an aqueous sodium hypochlorite solution. Another chlorine-containing compound is hypochlorous acid (HClO), which is similarly utilized as a disinfecting agent.
Hypochlorous acid is a particularly desirable disinfecting agent due to the effect of hypochlorous acid on bacteria and its lack of adverse health impacts on humans. In particular, when in the presence of bacteria, hypochlorous acid penetrates the bacteria and reacts with key enzymes to prevent normal respiration. Additionally, hypochlorous acid effectively eradicates pathogens other than bacteria. Accordingly, hypochlorous acid is often utilized as a disinfecting agent for surgical tools or hands of a surgeon in hospitals, and is similarly utilized as a disinfecting agent for surfaces utilized in the preparation of food by restaurants.
However, hypochlorous acid has an incredibly short half life and readily oxidizes. Other factors further contribute to the incredibly short half life of hypochlorous acid, such as temperature, exposure to ultraviolet light, etc. Moreover, hypochlorous acid partially dissociates into a hypochlorite anion (OCl−) when in an aqueous solution. As such, hypochlorous acid cannot be readily purchased and stored for any extended duration.
Accordingly, hypochlorous acid is generally generated in situ and utilized immediately upon being generated. However, conventional systems for generating hypochlorous acid in situ are large (and not portable) and very expensive. Moreover, conventional systems for generating hypochlorous acid in situ have outputs that are inconsistent. Specifically, conventional systems for generating hypochlorous acid in situ have outputs with varying pH, free available chlorine (FAC) and oxidation-reduction potential (ORP), which further limits repeatability and reproducibility of the conventional systems for generating hypochlorous acid in situ. Further, the free available chlorine (FAC) of the hypochlorous acid produced via conventional systems for generating hypochlorous acid is undesirably low, which limits the applications in which the hypochlorous acid may be utilized.

System and method for generating a chlorine-containing compound


A method for multi-target detection and an apparatus for multi-target detection are capable of detecting at least two targets in real time or near real time. The real-time detection or near real time detection can be achieved by at least one of a Recipe Group Approach, an End Member Grouping Approach, and a Pixelated Grouping Based Approach.

Spectroscopic imaging combines digital imaging and optical spectroscopy techniques, including Raman scattering, fluorescence, photoluminescence, laser induced breakdown, ultraviolet, visible, and infrared absorption spectroscopies in order to perform chemical analysis of materials. In some literature, this is referred to as hyperspectral imaging or chemical imaging. Such techniques are useful for analyzing various compounds.
One continuing challenge is to achieve detection tasks in real time, or at least close to real time. By achieving detection tasks in real time, spectroscopic imaging can be used in new applications, including surgical imaging, contraband detection, explosives detection, and the like. In each of these applications, there is a need for the user to visualize the target in real time because the user is about to or is presently interacting with the target or a person or object that that might contain the target. Another challenge is for spectroscopic imaging to be used in complex scenarios involving multiple different targets that must be detected. The present disclosure is addresses these and other challenges of current spectroscopic imaging technologies.

Apparatus and methods for multi-target detection


A linear actuator for a vehicle occupant restraint system is provided, which comprises a cylinder and a pulling element connected to the cylinder by means of a holding part. The linear actuator further comprises a piston which is shiftable within the cylinder and has a locking part. The locking part including a sealing part coaxial with to the locking part and a conical outer section. The conical outer section has an axial end at a side facing the sealing part and is provided with a peripheral groove at this axial end. Still further, the linear actuator comprises a plurality of locking bodies shiftably arranged between the conical outer section of the locking part and the inner wall of the cylinder.

A conventional linear actuator for a vehicle occupant restraint system comprises a cylinder, a piston shiftable therein and consisting of a locking part including a conical outer section and a sealing part coaxial with said locking part, and further a plurality of locking bodies shiftably arranged between said conical outer section of said locking part and the inner wall of said cylinder and a pulling element connected to said piston by means of a holding part.
Such a linear actuator serves to convert the energy of a highly pressurized gas into a tensioning stroke which may be used to eliminate the slack of a seat belt system by, for example, rotating the belt reel of a belt retractor in the coiling direction or by suitably displacing the buckle of a seat belt.

Linear actuator for a vechicle occupant restraint system


Materials and Methods for producing localized hypothermia in a patient for treatment of a weight disorder (e.g., obesity).

An average human adult requires about 2000-2500 Kcal/day. If the average human burns about the same amount per day, a net balance is generally maintained and the person's weight should remain steady. However, many people consume more calories than they burn. This can lead to obesity, a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to a reduced life expectancy and/or increased health problems, such as heart disease, type 2 diabetes, sleep issues, and cancer. A person can be considered obese if the person's body mass index (BMI; a measure of body fat based on height and weight) is greater than 30 kg/m2.
The current epidemic of obesity and its numerous complications have resulted in enormous economic and healthcare burdens. Treatments for obesity often include dieting and/or increasing physical exercise, but such conventional therapies can be ineffective and/or difficult to comply with. Anti-obesity drugs also can be taken to reduce appetite or inhibit fat absorption, and in severe cases, surgery can be performed. Weight loss supplements and surgery have their own complications, however.

Localized hypothermia to treat weight disorders

Mayo Foundation for Medical Education and Research