Minimum-size effects in asymmetric tilt-angle-implantedLDD-WNx-GaAs MESFET's

Asymmetric tilt-angle-implanted lightly doped drain (LDD)-WN_x -GaAs MESFETs with an optimized transconductance performance are discussed. A tilt-angle implantation is used to reduce the parasitic source resistance below the gate sidewall without increasing short- and narrow-channel effects. This leads to a transconductance increase of nearly 25% for submicrometer FETs while the gate-source capacitance increase is almost negligible. The influence of the implantation angle on the threshold voltage transconductance, and Schottky-barrier characteristics is reported     

Traveling wave optical modulator using a directional coupler LiNbO3waveguide

Fabrication methods for low drive voltage and broad-band LiNbO3waveguide directional coupler optical modulator are described. Optical waveguides were prepared by conventionaly Ti in-diffusion into LiNbO3c-cut plate. To obtain wide-band frequency response, traveling wave electrodes were used. Electrode characteristic impedance measured by time domain reflectometry method coincided well with the calculated value by conformal mapping. Measured electrode conductor losses followed square root of frequency. To reduce electrode conductor losses, asymmetric and 3-μm thick Al electrodes were used. Directional coupler optical modulator frequency response was analyzed, using the phase difference average value along the propagation directions. Calculated value by this method coincided well with measured value obtained by a swept frequency technique. The characteristics of this modulator at the 1.317-μm wavelength are as follows: 100 percent modulation voltage is 4 V, extinction ratio is 17 dB, optical insertion loss is 5.4 dB, 3-dB bandwidth is 3.6 GHz, and rise time is about 400ps.     

Extraorbital giant cell angiofibromas

Resveratrol 3-O-beta-D-glucopyranoside (1) has been isolated from the seeds of Erythrophleum lasianthum (Caesalpinioidae, Leguminosae), a South African plant used in traditional medicine, and has shown antiplatelet aggregation activity. The synthesis of 1, related hydroxystilbenes, and their glucosides has been undertaken to provide larger quantities, for further biological evaluation, and has been accomplished via Wittig reactions followed by glucosylation under phase transfer catalysis.     

High-efficiency electroabsorption in quaternary AlGaInAsquantum-well optical modulators

Quaternary AlGaInAs quantum-well optical modulators operating at 1.55 μm are introduced and demonstrated for the first time. An electron-to-heavy-hole exciton absorption peak shift of over 600 Å is observed for a bias voltage of 6 V. An extinction ratio of 19 dB and high-speed operation over 4 GHz is obtained for this optical modulator     

Expression and properties of feline herpesvirus type 1 gD (hemagglutinin) by a recombinant baculovirus

We constructed a recombinant baculovirus expressing feline herpesvirus type I (FHV-1) gD in insect cells (Sf9 cells). The expressed product was identified as FHV-1 gD by a panel of monoclonal antibodies specific for the FHV-1 gD, and had an apparent molecular mass of approximately 49 kDa, which was less than that of the authentic FHV-1 gD. When the FHV-1 gD protein were expressed in Sf9 cells and CRFK cells in the presence of tunicamycin, the FHV-1 gD exhibited a molecular mass of 41 kDa. It was shown that the gD protein was transported to the surface of recombinant virus-infected Sf9 cells when examined by membrane-immunofluorescence analysis, and that the gD expressed on the surface of Sf9 cells adsorbed feline erythrocytes. Mice inoculated with a lysate of Sf9 cells expressing FHV-1 gD induced antibodies with virus-neutralizing and hemagglutination-inhibition activities. Therefore, the expressed gD appears to be biologically authentic. These data suggested that recombinant FHV-1 gD produced in Sf9 cells may be a useful immunogen as a feline vaccine.     

New chemical etching solution for InP and GaInAsP gratings

A new chemical etching solution of bromine-water system, which is suitable for transforming the fine resist grating mask pattern onto InP and GaInAsP surfaces, is reported. The Br2:H2O:H3PO4 (or HCl) solution does not dissolve AZ 1350 photoresist and exhibits both moderate etching rate and a pit-free etched surface.     

Fabry-Perot cavity type 1.5 ?m InGaAsP BH-laser amplifier with small optical-mode confinement

A 1.5 ?m InGaAsP buried-heterostructure laser amplifier having small optical-mode confinement was fabricated with a Fabry-Perot cavity configuration. Its signal gain, saturation output power and noise characteristics were studied and found to be superior to those for AlGaAs amplifiers, as a result of small optical-mode confinement.     

Effects of catalyst and vehicle in coal liquefaction

Experiments have been carried out, using a semi-batch reactor equipped with a consecutive sampling device, to clarify the effects of catalysts and vehicles in the coal liquefaction process. The results show that a vehicle has a significant effect during preheating, unlike a catalyst which is not effective at this stage. A catalyst is more effective in promoting liquefaction under reaction conditions of 450°C and ≈ 20 MPa than is a vehicle. A vehicle higher in hydrogen donation increases the yield of oil even if a catalyst is present, providing a multiplier effect. In the development of a direct coal liquefaction process, therefore, selection of a vehicle is as important as that of a catalyst.     

Induction of platelet-activating factor in mice by intravenous administration of a neutral fraction of bakers' yeast mannan

A neutral subfraction of mannan of bakers' yeast (WNM) was found to show a lethal effect in mice when administered intravenously. Symptoms caused by intravenous (i.v.) administration of WNM resembled those resulting from the administration of platelet-activating factor (PAF). CV-3988 and ONO-6240, selective PAF antagonists, prevented hypotension and death caused by the administration of WNM or PAF. A β-adrenoceptor agonist was shown to prevent death caused by WNM, whereas propranolol increased the lethal activity of WNM. Intravenous administration of WNM into mice produced PAF in gall bladder fluid which was determined by platelet aggregation assay. The findings indicate that WNM is able to induce PAF in mice and that the resultant PAF may participate in the WNM-induced lethal activity observed in mice.     

New annealing method and CaGe garnet film coercivity origin

A new annealing method which drastically reduces the coercivity of GaGe-garnet films grown by LPE has been developed. The as-grown films of (YSmLuCa)₃(FeGe)₅O₁₂ and (YEuTmCa)₃(FeGe)₅ O₁₂ are sealed with Y₂O₃ and metal Ca in an evacuated tube having three chambers. When heated, the tube is filled with Ca and O₂ gases which are supplied from the metal Ca and Y₂O₃, respectively. Ca and oxygen are believed to be incorporated into the film occupying the dodecahedral cation vacancies and oxygen vacancies, respectively. By this annealing, coercivities higher than 5.0 Oe are drastically reduced to less than 0.5 Oe. At the same time, the 4πMs and lattice constant af are decreased, while the Curie temperature T_c is increased. A point defect structure model containing c-site vacancies, oxygen vacancies and a-site Ge²⁺ ions is proposed. The origin of the coercivity is believed to be the oxygen vacancies.