Integrated multi-biosensors based on an ion-sensitive field-effecttransistor using photolithographic techniques

Two kinds of multifunctional biosensors, one sensitive to glucose and triolein and the other to glucose and urea, have been constructed using semiconductor fabrication techniques. An integrated ISFET (ion-sensitive field-effect transistor) with three hydrogen-ion-sensitive FET elements on one chip was used as a transducer for the biosensor. A photolithographic technique with a water-soluble photocrosslinkable polymer made possible the deposition of patterned enzyme membranes (glucose oxidase, lipase, and urease membranes) and bovine serum albumin membrane around each gate surface of ISFET elements. The multibiosensor for measuring glucose and triolein concentrations determined both glucose concentrations up to 5 mM and triolein concentrations up to 3 mM simultaneously. The biosensor for glucose and urea has a detection range of 0.03 to 3 mM for glucose and 0.1 to 20 mM for urea. Some multibiosensors showed a cross-sensitivity problem due to enzyme contamination. An improved membrane fabrication method to prevent the enzyme contamination is described     

The 121‐contiguous‐subfield addressing of high Xe‐content PDPs

Abstract— As the Xe content of PDPs is increased, the space‐charge priming becomes more effective. Also, the diffusion/drift of the space charges and accumulation of the wall charges becomes faster. These facts indicate that the use of an erase addressing is preferable for high‐Xe‐content PDPs. A 30%‐Xe green test panel was driven with contiguous subfields using erase addressing and a grouped Address‐While‐Display scheme. Crosstalk was suppressed by driving the odd and even sustain electrodes separately. The fast addressing speed of 0.283 μsec allowed for 121 subfields and 122 gray levels, with a resultant luminance of 4200 cd/m² and a dark‐room contrast of 310:1. The scan and data pulse voltages were as low as 90 and 75 V, respectively. All the subfields had an identical length of 136 μsec, but the number of sustain pulses in these subfields could be varied between 2 and 20. By selecting an adequate number of sustain pulses in the subfields, arbitrary gamma characteristics could be realized. A gray‐scale expression having a constant difference between the consecutive “perceived” luminance levels was verified throughout all the luminance levels.     

Effects of Injection Molding Parameters on the Production of Microstructures by Micropowder Injection Molding

Micropowder injection molding (μPIM) is a potential low-cost process for the mass production of metal or ceramic microstructures. In order to obtain good molded microstructures and to avoid molding defects, it is important to select suitable injection molding parameters. In this paper, the selection of injection molding conditions for the production of 316L stainless steel microstructures by μPIM is presented. Silicon mold inserts with 24 × 24 microcavities were injection molded on a conventional injection molding machine. The dimensions of each microcavity were Φ 100 μ m × depth 200 μm, giving an aspect ratio of 2. The distance between each microcavity was 200 μm. Five sets of experiments were conducted by varying one injection molding parameter at a time. The parameters included injection pressure, holding pressure, holding time, mold temperature, and melt temperature. Higher injection pressure and holding pressure were required during the injection molding process due to the small dimensions of the microcavities and the large number of microcavities (576 microcavities). High mold temperature was required for complete filling of the microcavities. Molded microstructures without visual defects were obtained using appropriate injection molding parameters. Catalytic debinding and sintering of the 316L stainless steel microstructures were successfully conducted.     

Metal vapor treatment for enhancing the dissolution of platinum group metals from automotive catalyst scrap

A new process for dissolving platinum group metals (PGMs) from automotive catalyst scrap using metal vapor was proposed. To improve the PGMs dissolution ratio from scraps, vapor of reactive metals (R), such as magnesium (Mg) or calcium (Ca), was reacted with the automotive catalyst scrap in a closed stainless steel vessel at 1173 K for 3 hours. Under these experimental conditions, Mg and Ca vapor was supplied to the entire body of catalyst scrap. After the reactive metal treatment, the specimens were crushed and dissolved in aqua regia at 323 to 333 K for 1 hour. The PGMs dissolution ratios were improved after the reactive metal treatment, and the dissolution ratios reached 88 pct in Pt, 81 pct in Pd, and 72 pct in Rh, while they were 77 pct in Pt, 69 pct in Pd, and 38 pct in Rh without the treatment. Even when the specimens were dissolved in aqua regia without heating, the PGMs dissolution ratios from the catalyst scrap after reactive metal treatment showed high values, 78 pct in Pt, 74 pct in Pd, and 57 pct in Rh at a maximum. These results show that the reactive metal treatment is effective for the recovery of PGMs from automotive catalyst scrap.     

DC breakdown voltage characteristics of saturated liquid helium in the presence of metallic particles

This paper deals with the breakdown voltage characteristics of saturated liquid helium in the presence of a needle-shaped or spherical metallic particle to obtain insulation design data for pool-cooled, low-temperature superconducting coils and to find the predominant factor affecting the breakdown voltage of liquid helium at a given state. The results show the following. (1) The generation of bubbles at the instant of collision of a particle with an electrode is caused mainly by the kinetic energy released from the moving particle to the liquid helium, while the electrostatic energy accompanying the microdischarge between the particle and the electrode has a lesser effect on it. (2) The lowest breakdown voltage at different particle conditions appears in the case of a free needle particle. The low breakdown voltage is caused by the bubble triggered by the particle collision, the high electric field at the tip of the needle particle, and the rich initial electrons supplied by the microdischarge.     

Microcollimated laser diode with low wavefront aberration

A microcollimated laser diode (MCLD) utilizing a 1-mm short focal length, φ0.5-mm small diameter micro Fresnel lens (MFL) as the collimating lens is discussed. The MCLD is assembled with a 780-nm quantum-well laser diode dice and an MFL in the smallest commercially available laser package. The radiated laser beam from the MCLD has a power of higher than 2 mW at 50 mA driving current, a φ2 mm beam diameter with a nearly Gaussian intensity profile, and a low wavefront aberration of less than λ/14 (RMS value) measured at a 1-m distance     

Receiver Designs for Fiber Optic Communications Optimization in Terms of Excess Noise Factors That Depend on Avalanche Gains

The optimizations of signal-to-noise ratios (SNR's) and pulse error rates in fiber optic receivers are investigated in terms of an avalanche photo diode (APD) model in which excess noise factors depend on the avalanche gains. The optimization of SNR results in an analytical solution for the optimum avalanche gain. A numerical example compares the result with those of conventional SNR optimization where excess noise factors do not depend on avalanche gains. Improvements of around 2 dB in the accuracy of the optimum SNR's are expected. It is shown that the optimization of pulse error rates for digital transmissions can not be attained analytically. This problem is solved by the use of approximate representations of excess noise factors. Two approximate representations are illustrated that provide very simple and accurate analytical solutions. Numerical examples demonstrate the efficacy of these approximate solutions.