Abstract: A process for obtaining a multifunctional, ion-selective-membrane sensor is disclosed, which process comprises the following steps:a) preparation of a siloxanic prepolymer, followed by one or more deposition(s) of said siloxanic prepolymer on a device of MOS or ISFET type;b) preparation of a solution containing an ionophore, a monomer of a polymerisable olefin, 2,4-toluenediisocyanate and a dialcohol or a diamine or a glycol or a trialcohol or a triamine, which preparation is followed, after that said solution has been kept stirred for at least 48 hours at room temperature, by the deposition thereof on the siloxanic prepolymer, which deposition is carried out by means of a spinner;c) photochemical treatment in the presence of a photoinitiator by means of UV light, with a suitable mask being used, which allows the exposure to UV light to take place on one gate only;d) chemical washing of the sensor, by means of an organic solvent;e) thermal treatment ("thermal curing"), so as to complete the reactions of polym

Abstract: A probe for use in non-destructive measuring of electrical resistance of a high current electrical connection between two high current electrical conductors, each of the conductors having a longitudinal exterior surface, the probe comprising: an articulated body being articulated about a longitudinal axis; a plurality of electrodes provided on an interior portion of the articulated body for engaging about the longitudinal exterior surface; connecting means for releaseably connecting the articulating body around the longitudinal exterior surface, the connecting means including resilient means cooperating with the plurality of electrodes for causing the electrodes to resiliently engage the surface, the electrodes being located on the probe body to be arranged substantially evenly around and on the longitudinal exterior surface of the corresponding conductor in a plane substantially perpendicular to a current flow in the conductor; and resistors connected in series with each electrode, each of the resistors havi

Abstract: The present invention is characterized by a solid body disposed so that a remarkably small gap may be formed between it and a surface of an electrode. A super-thin liquid membrane is formed in the small gap by an interfacial tension of a liquid. An object to be measured is applied to or acted upon either the solid body or the super-thin liquid membrane. An electric signal due to the physical properties of the super-thin liquid membrane itself or an electric signal due to a chemical or physical reaction, which is generated on an interface of the solid body and the super-thin liquid membrane and diffused through the super-thin liquid membrane itself, is detected by means of the electrode to measure the physical properties of the object to be measured.

Abstract: A test adapter is disclosed for connection to a measuring instrument using a 4-conductor measuring technique. It has four coaxial connectors whose characteristic impedance is adapted to that of the measuring instrument. The supply lines are designed as a stripline whose characteristic impedance is equal or approximately equal to that of the coaxial connectors.

Abstract: The sensor comprises a chip of a semiconductor material wherein a field-effect transistor is formed the drain and source regions whereof are provided on a first face of the chip, onto which an ion-selective membrane is applied which is coupled to said field-effect transistor.The membrane covers said first face of the chip completely, and terminals are provided in addition which comprise conductive elements applied to the other face of the chip and being connected to said drain and source regions by connections which extend through the chip.These connections are formed by a method providing for the formation in the chip of buried layers of semiconductor material.

Abstract: A conductivity measuring device comprises a low-potential intermediate electrode which is capable of being in connected state by a switch and which is disposed between a couple of measuring electrodes for transmitting and receiving. Each of said electrodes is made contact with a body to be tested so that the conductivities of the surface and the inner portion of said body to be tested can be measured, respectively.

Abstract: A reactive gas detection system provides early warning of gas emissions that often occur in developing fire conditions in environments such as telephone system central offices where halogenated substances, for example polyvinyl chloride wire insulation and brominated fire retardant materials, are prevalent. Multiple microbalance detectors (122) comprising quartz crystal oscillators coated with a layer of zinc or zinc compound are distributed about a premises and the rate of change of crystal oscillation frequency is cyclically monitored by a frequency counter (130) under control of a data processor (112). The detectors are specifically reactive to the halogen acid gases emitted during pyrolysis of the noted substances and exhibit a significant differential frequency change in the presence one or more of these gases well in advance of the outbreak of flame, smoke, or other normally detectable combustion products.

Abstract: Several types of new microelectronic devices including diodes, transistors, sensors, surface energy storage elements, and light-emitting devices are disclosed. The properties of these devices can be controlled by molecular-level changes in electroactive polymer components. These polymer components are formed from electrochemically polymerizable material whose physical properties change in response to chemical changes, and can be used to bring about an electrical connection between two or more closely spaced microelectrodes. Examples of such materials include polypyrrole, polyaniline, and polythiophene, which respond to changes in redox potential. Each electrode can be individually addressed and characterized electrochemically by controlling the amount and chemical composition of the functionalizing polymer. Sensitivity of the devices may be increased by decreasing separations between electrodes as well as altering the chemical environment of the electrode-confined polymer.

Abstract: Apparatus and methodology for mapping the superconductive properties of a sample of superconducting material. The material is cooled so that it is a mixed state and an alternating magnetic field is induced in a portion of the sample to be tested. The harmonic component of the induced alternating magnetic response is measured at a location proximate to the point of induction. As the inducing and measuring devices are displaced relative to the sample the measured amplitude of the harmonic component is stored in suitable storage means as a function of location in the sample. Thus, a map of the superconducting properties of the sample may be generated.

Abstract: The operating temperature of the active region of an RF semiconductor device such as a microwave hybrid circuit having a gallium arsenide field-effect transistor therein is determined by measuring signal gain of the device at variable times following application of bias voltage to the device. Bias voltage is applied in response to a constant duty cycle pulse train from which are derived a sample-and-hold command pulse and a synchronized bias control pulse.

Abstract: Two lead wires for each, connected to opposite ends of a heat generating element are secured to a holder. These lead wires form four-point-terminals at their other ends and thereby a disposable sensor is provided. A current source and a voltmeter are connected to the terminal and changes in various properties of fluid are determined on the basis of a value of current supplied from the current source and a value of voltage measured by the voltmeter.

Abstract: A conductivity detector includes an A.C. voltage supply and control circuit for applying a pair of electrodes disposed within a cell filled with electrolyte with a predetermined A.C. voltage and a correction signal generating circuit for generating a A.C. reference signal. At an auto zero adjustment operation, an output A.C. current signal flowing through the electrolyte is detected and the A.C. current is added to the A.C. reference signal. In advance of measuring conductivity, the amplitude of the A.C. reference signal is corrected until the resultant signal of the A.C. output current and the A.C. reference signal reduces to zero.

Abstract: The resistivity of particulate matter in a gas stream, such as a combustion gas stream produced in a coal-fired power plant, is measured by collecting a sample of the particulate on the surface of a porous ceramic cylinder, either with or without an applied collection voltage, and then determining the resistance of the sample with a compound measurement electrode having multiple conductors. The reference electrode and the measurement electrode are spirally wound on the ceramic cylinder in an interdigitated manner, so that the two are laterally adjacent down the length of the cylinder. The pressure within the cylinder is controllable, with a pressure below atmospheric being applied to draw the particulate to the suface and ascertain when a sufficient sample for measurement is present, and a pressure above atmospheric being applied to blow away the sample after the measurement is completed, thereby preparing the instrument for the taking of another sample.

Abstract: An apparatus for measuring the resistance of a test specimen includes an insulated-gate-bipolar-transistor (IGBT transistor) which is provided for applying a test current to the test specimen. A voltage measuring unit is provided including a serial connection of a voltage measuring device and an MOS transistor. A current measuring device is provided for measuring the test flowing through the test specimen. The voltage measured by the voltage measuring unit is used to compensate for the voltage drop across the IGBT transistor when calculating the resistance of the test specimen.

Abstract: Apparatus for measuring electrolyute concentrations in fluid samples. The apparatus includes an ion selective electrode having a plurality of ion selective detection sites. Each site has an affinity for a preselected electrolyte of interest and generates a potential having a magnitude related to the concentration of the corresponding electrolyte in the sample. A voltage to optical transducer circuit is provided to convert the voltage differentials to optical signals having intensity related to the concentration of the electrolytes in a first embodiment, a digital code related to the concentration of the electrolytes in a second embodiment, and an optical absorption or density value related to the concentration of the electrolytes in a third embodiment. The optical signals are suitable for detection by conventional optical detector apparatus of assay instruments and may be processed using conventional two point linear interpolation techniques to determine the concentrations of the preselected electrolytes.

Abstract: A method and apparatus for measuring resistivity employ the four-point probe method to measure the surface resistivity or volume resistivity of a sample. The method includes inputting sample shape information and calculating a resistance correction coefficient for the sample based on the shape information and information relating to a measurement position on the sample. The sample surface resistivity or volume resistivity is calculated by multiplying a resistance value, which is measured in accordance with the four-point probe method, by the correction coefficient.

Abstract: Devices and methods are provided for determining the presence and amount of an analyte by measuring a redox potential-modulated photoinducing signal from a photoresponsive element. Further devices and methods are provided for determining the presence and amount of an analyte by measuring a redox potential, pH or ion modulated photoinduced signal from a photoresponsive element, where one signal is a constant system and the other signal(s) is a variable system. The constant system signal is used to standardize the variable system signal. Various protocols may be employed where an analyte may be directly or indirectly coupled to a redox couple, a pH or ion system for detection. The latter devices employ a photoresponsive element having a medium contacting surface, which is partially covered with an electronically conducting layer and partially covered with a protective insulative layer.

Abstract: A portable meter for measuring the impedance of a resistance welding circuit between first and second points on the apparatus. The meter is powered by conventional alternating current and conducts a test alternating current through the welding apparatus at such an amperage so that the voltage measured between the first and second points is equal to the impedance therebetween.

Abstract: A method and apparatus for process control in both the production of uniform material layers using vapor deposition, sputtering, chemical deposition, etc. and the treating of material layers. In particular, the process and apparatus are particularly useful in semiconductor fabrication where ion implantation or diffusion is used. A brief test signal of preset shape, frequency spectrum, or frequency sequence is applied at given time intervals to the material layer whose production characteristics need to be monitored. The measuring signal is applied to a digital evaluation circuit in a process control computer. The signal has various components whose time constants and/or conductivities are different from one another and which together are characteristics of the current flowing through the layer being monitored. In particular, the current flowing over the surface layer i.sub.1, the current flowing through particle houndary areas i.sub.3, and the current through homogeneous material ranges i.sub.

Abstract: A corn moisture tester is adapted to measure the moisture content of corn kernels on an ear of corn. The ear of corn may be affixed to the corn stalk. The device includes an ear cradle, a pair of electrode blades and circuit for measuring a moisture-dependent electrical property of the corn kernels. The cradle is adapted for receiving an ear of corn and includes two portions hinged together so they may be opened to receive the ear. When the cradle portions are closed, they form a substantially cylindrical interior cradle surface for engaging the ear of corn. The conductor blades are mounted to one portion of the cradle to pierce the kernels but not the cob when the cradle is closed about an ear under test. The electrical property measuring circuit generates and displays a signal representative of moisture.

Abstract: A metal-insulator-semiconductor (MIS) diode having a suspended electrode forming a cavity between the electrode and the insulator is operated in the charge storage, i.e. inversion, mode to detect a fluid concentration. A reverse bias voltage is applied to the diode to form a charge inversion layer in the semiconductor, the bias is disconnected and subsequently reapplied. The charge that flows upon reapplication of the bias voltage is a measure of the concentration of a fluid in the cavity. An array of MIS diodes with multiplexed biasing and charge measurement permits detection of combinations of different fluids, even in the presence of potentially interfering chemical species.

Abstract: This device provides an electric signal linearly dependent on the oxygen content of a gas without the need of a reference gas; it is constituted by a solid electrolyte substrate (3) coated with two separate electrodes (1,2) connected to the terminals of an electric voltage source. In the presence of a gas of which the content of oxygen must be measured and when a given voltage is applied between the two electrodes (1,2), oxygen molecules are ionized in the region of the electrolyte close to the cathode (1). The current which flows between the two electrodes (1,2) constitutes the measuring electric signal provided by the sensor.

Abstract: There is provided a novel method of testing for the presence of an analyte in a fluid suspected of containing the same. In this method, in the presence of the analyte, a substance capable of modifying certain characteristics of the substrate is bound to the substrate and the change in these qualities is measured.While the method may be modified for carrying out quantitative differential analyses, it eliminates the need for washing analyte from the substrate which is characteristic of prior art methods.

Abstract: A method of producing an exhaust gas sensor incorporating BaSnO.sub.3. Stannate ion and barium ion are reacted in a strong alkali to precipitate water-containing crystals of BaSnO.sub.3 such as BaSnO.sub.3.3H.sub.2 O, BaSnO.sub.3.5H.sub.2 O or the like. When thermally decomposed, the precipitate gives BaSnO.sub.3 free from segregated Ba and Sn elements. The product was then molded and thereafter sintered to obtain the sensor.

Abstract: A temperature detector comprises a pyroelectric device (10) having electrodes (11, 12) on both main surfaces, with an insulating film (13) formed on one of the main surfaces. An impedance converting circuit formed of a field effect transistor (20) and resistance elements (18, 19) is electrically and physically connected between an electrode (11) exposed through a hole (14) formed in the insulating film and electrodes (15, 16, 17) formed on the insulating film. The detector is entirely covered by molded resin (24). Consequently, problems of disconnection and short circuit of leads between the pyroelectric device and the impedance converting circuit can be eliminated.

Abstract: A circuit for physical placement within an underground well to amplify low level differential DC voltage signals measured at a well casing is disclosed. The circuit incorporates an instrument amplifier with a first switching device before the amplifier and an inverter after the amplifier in the signal path. A second switching device selectively connects one of the amplifier and inverter outputs to a low-pass filter. The switching devices operate synchronously under control of an operating clock signal so that DC error terms associated with the amplifier are converted into a substantially AC error signal while maintaining the signal being amplified as a DC signal. The duty cycle of the operating clock signal is established to cause the substantially AC error signal to include a DC component of appropriate polarity and magnitude to compensate for DC error terms associated with the inverter and low-pass filter.

Abstract: A resistance ceramic heater including a ceramic substrate, and a heating element which has a resistance heat-generating portion, and electrical leads connected to the heat-generating portion for energizing the heat-generating portion to generate heat. The heat-generating portion consists of a plurality of electrically resisitive heat-generating conductors formed in parallel connection with each other and in series connection to the electrical leads, and a plurality of connecting conductors which connects the heat-generating conductors, at a plurality of connection points on each of the heat-generating conductors. The connecting points are spaced apart from each other along the length of each heat-generating conductor. An electrochemical element and an oxygen analyzer or sensor which uses the ceramic heater are also disclosed.

Abstract: Devices and methods are provided for making a plurality of determinations of the local (site-specific) redox state of a liquid system, by employing a photoresponsive element, which can be independently irradiated at different sites to provide independently detectable signals.

Abstract: Compensation for the temperature sensitivity of the output of a potentiometrically operated ISFET probe whose drain-source voltage and drain-source current are held constant is provided by using a Nernstian temperature correction of the difference between the ISFET output and the isopotential voltage of the probe and offsetting the resulting difference by the isopotential pIon value. An ISFET/NISFET pair provides a cancellation of variations due to manufacturing.

Abstract: A description is given of sensors in in the form of field effect transistors and capacitors which are suitable for qualitatively and quantitatively determining species to be analyzed, for example molecules or ions, in liquid or gaseous media. A special field of application is the selective determination of the presence and concentration of gases. The sensors are defined in that they have a sensitive layer consisting of a heteropolysiloxane.

Abstract: Devices and methods are provided for making a plurality of determinations of the local (site-specific) redox state of a liquid system, by employing a photoresponsive element, which can be independently irradiated at different sites to provide independently detectable signals.

Abstract: A gas sensor comprises a photovoltaic cell which, upon exposure to light, develops a photovoltage or photocurrent which varies as a function of the type of gas sorbed. The cell includes in order a conductor, an N-type light-absorbing semiconductor, and a thin light-transmitting gas-absorbing metal Schottky layer having electrical properties which vary with the type of gas sorbed therein.

Abstract: The invention relates to a system for determining the current thickness of changing coatings of a material on a substrate, using an electrically excitable, mechanically vibratable element (2) having at least one pronounced resonant frequency, which is excited to a steady vibration by an oscillator circuit (1) at a resonant frequency, and which is covered by the material in the same manner as the substrate. A signal (U.sub.D) is produced which depends on the damping caused by the coating of the vibratable element (2). This signal (U.sub.D) is compared with a known critical value signal (U.sub.DE) whereby it is possible to indicate when the vibratable element (2), which can be coated with the material only to a certain degree, must be replaced with a new vibratable element (FIG. 2).

Abstract: There is provided a multifunctional ceramic sensor and technology which is capable of detecting temperature, humidity and gas with a single sensing element made of p-type metal-oxide porous ceramic semiconductor Ba(Ti.sub.1-x Sn.sub.x)O.sub.3 (x=0.05-0.5). The sensing element is prepared by special ceramic technique which is formed on porosity and sintered on green pack that form a kind of network of capillary pipe with tree-like structure in three dimensions. The present invention posses advantages are as follows: high sensitivity, fast response time, small hysteresis, good separability, high reproducibility and long durability. The multifunctional ceramic sensor not only use for air conditioners, driers, cookers and microwave ovens but also use to detect or control the temperature-humidity-gases for food stuff, tobacco, leather, textile, print, dye and petrochemical industry.

Abstract: Disclosed is a CO gas detecting device which comprises a CO gas sensor provided with a gas sensitive member made of SnO.sub.2, ZnO, Fe.sub.2 O.sub.3 or the like, a pair of electrodes provided on said gas sensitive member, and a catalyst layer comprising at least one kind of catalyst metals of Pt, Pd and Rh and at least one kind of carriers of Al.sub.2 O.sub.3, ZrO.sub.2 and SiO.sub.2, provided on said gas sensitive member; and a reference sensor substantially without sensitivity to CO gas provided with a gas sensitive member similar to the above gas sensitive member, a pair of electrodes provided on said gas sensitive member and a catalyst layer comprising Ag and at least one kind of carriers of Al.sub.2 O.sub.3, ZrO.sub.2 and SiO.sub.2, provided on said gas sensitive member. Also disclosed is a circuit for driving the device.

Abstract: In a semiconductor sensor, the surfaces of first and second semiconductor substractes of a first conductivity type are made into flat surfaces by polishing the surfaces and are contacted each other so that the both substrates are bonded together. Source and claim regions are formed by diffusing an impurity of second conductivity type. The source and claim regions are separated through a through hole formed in the second substrate and are extended along the surface of the second substrate. An insulative layer is formed on the opposite surface of the second substrate and an inner surface of the through hole.

Abstract: The present invention describes devices capable of sensing changes of acidity in a non-aqueous medium. The devices are particularly useful for determining the alkaline reserve in a motor vehicle lubricating oil.

Abstract: Disclosed is a method of determining the state of charge and discharge of a host material, e.g., a hydride forming hydrogen storage material, or the interstitial content of an alloy material by the high frequency measurement of the time varying transfer function thereof.

Abstract: A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicondioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies.

Abstract: A vapor or gas detector (12) that forms an element of a vapor or gas detecting and alarm system (30). The detector in one of its embodiments is configured as a three-section dynamic junction (16) consisting of a resilient substrate (22) having a resonant mechanical element (18) attached to its back and an absorbate (20) to its front. When no toxic vapors or gases are present, the element (18) is under a no-strain, no deformation condition and emits a first frequency signal. When a toxic vapor or gas is present, the absorbate (20) absorbs the gas or vapor which causes the substrate (22) to deform and, in turn, causes the element (18) to deform and emit a second frequency signal. This second frequency signal is applied to the system (30) where the signal, through a series of electronic circuits is processed. The processed signal activates a lamp (44a) and an audible alarm (44a) indicating that the detected vapor or gas has exceeded a preselected toxicity level.

Abstract: This invention introduces a new class of devices for detecting the presence of biological molecules. The construction principle of the device involves the direct introduction of small monomers of macromolecules into the surface layer of a semiconductor, for example by doping at the gate-area of a field effect transistor (or any other similar suitable electronic device, also on carbon basis). There are a few biological monomers which pair specifically enough for a selective measurement, such as nucleotides (or portions thereof, e.g. adenine, thymine, guanine, cytosine and uracil). This invention leads to substantial improvement of biosensors, as there should be: Better signal to noise ratio, and options for: reading of nucleotide sequences, better process control, and new synthesis possibilities (e.g. modified Merrifield Synthesis). The invention also offers the potential to construct cybernetic systems and true biochips.

Abstract: A method and apparatus for assaying a species in a biological sample fluid. The apparatus comprises an SAW device (1) comprising a slab (2) of piezoelectric material on the upper surface (5) of which is formed an input transducer (3) and an output transducer (4). A source of RF energy is applied to the input transducer to generate a surface acoustic wave. Applied to the surface (5) is a thin layer (8) of a material capable of binding a species to be assayed. The sample (13) to be tested is applied to the top of the layer (8). A collimated light beam (1) from a source (9) is applied to the thin film from underneath the slab (2) and is collected by a photodetector (12). When the slab (2) is energized, the vibration sets up an effective diffraction grating which is coupled to the thin film and acts to diffract the light beam (10) applied to it. The energy in the diffracted beam, as measured by the photodetector ( 12), is indicative of the progress and result of the reaction between the layer 8 and the sample.

Abstract: An apparatus for detecting the concentration of certain analytes, including hydrocarbons, in a liquid medium, is disclosed. The apparatus uses a planar or "open" capacitor containing an active layer. In response to selected analyte in the liquid medium, the active layer causes capacitance to decrease with increasing analyte concentration. The capacitance decreases because higher dielectric water molecules are displaced from a region of the capacitor's electric field. For certain hydrocarbon analytes having high Henry's Law constants, the active layer causes bubbles to nucleate in the liquid medium on the surface of the active layer. Bubble formation displaces water molecules and decreases capacitance.

Abstract: A Sensor for measuring oxygen partial pressures in hot gases includes a semiconducting nonstoichiometric oxide material in the form of a solid solution in uranium dioxide UO.sub.2 of at least one other metal oxide having an oxygen/metal (O/M) ratio of less than two and a uranium/other metal (U/M) ratio such that the material has n-type conductivity. The sensor further includes at least one pair of electrodes contacting the nonstoichiometric oxide material at spaced apart locations for connection to a device for determining the resistance of the material between the electrodes.

Abstract: A depletion mode chemically sensitive field effect transducer device has a gate region adapted to interface with a solution so as to generate an electrochemical interfacial potential. A d.c. voltage potential is applied between the source and drain to cause a source-drain current to flow when a variable conductance channel connects the source and drain. A time-variant bulk potential is applied to the substrate and alternately opens and closes the conductive channel. The chemical property of interest of the solution thus can be determined by variations in bulk threshold voltage levels at which a predetermined source-drain current flows, without the use of a reference electrode in contact with the solution.

Abstract: Devices and methods are provided for making a plurality of determinations of the local (site-specific) redox state of a liquid system, by employing a photoresponsive element, which can be independently irradiated at different sites to provide independently detectable signals.

Abstract: A field effect transistor-type sensor comprising a field effect transistor device incorporated with a sensitive means exhibiting electric variation due to a physical or chemical interaction with the physical quantity to be detected, wherein an auxiliary electrode for the application of a drift-cancellation voltage to said sensitive means is located on said sensitive means, thereby suppressing the influence of impurities and/or ions contained in the sensitive means and/or the interface between the sensitive means and the field effect transistor device, or impurities and/or ions contaminating the device from the external atmosphere during use thereof, on the operation and/or the output of the field effect transistor device, and maintaining the stable output characteristic over a long period of time.

Abstract: The apparatus (10) for determining the activity of an ion (pIon) in a liquid (16) comprises a measuring circuit (10) including an ion sensitive field effect transistor (ISFET 12), a reference electrode (32) adjacent the ISFET (12), a temperature sensor (34) adjacent the ISFET (12), amplifiers (22 and 38) coupled to the ISFET (12) and temperature sensor (34), and control, computing and memory circuits (30, 44, and 46) coupled to the amplifiers and operable to maintain two of the following three parameters, V.sub.gs (gate-source potential), V.sub.ds (drain-source potential) and I.sub.D (drain-source current) at a constant value so that the third parameter can be used for determining the ion activity or pIon. The pIon sensitivity of the apparatus (10), as a function of temperature and/or the variation of the drain-source current, I.sub.D, as a function of the temperature are controlled by controlling the V.sub.gs so that the pIon can be calculated from a formula stored in the memory (46 ).

Abstract: A nondestructive method is proposed for measuring stripe dimensions in order to grade light-emitting structures such as lasers. The width of the near-field emission parallel to the stripe is measured while the laser is operating below threshold. This measurement is correlated with the actual stripe width and with the possibility of kinks developing in the light output. The width of the far-field emission perpendicular to the junction plane can also be measured, and the product of the two widths can be correlated with the stripe area and the possibility of kinks in the laser output.

Abstract: A method is disclosed for forming a chemically sensitive field-effect transistor having a suspended gate which enables the uniform and reproducible manufacture of such devices. Controlled uniformity and device response is provided by this method which makes the field-effect transistors suitable for use as sensors, alarms and analyzers for gases. A method of regenerating a chemically sensitive field-effect transistor having a suspended gate is also disclosed.