An electrostatic microactuator using LIGA process for a magnetic head tracking system of hard disk drives

 We demonstrate an electrostatic micro actuator which is fabricated by LIGA process. The actuator is designed for a magnetic head tracking system of hard disk drives (HDDs). The actuator is essential to achieve very high track density of HDDs. We realize the aspect ratio of 125 by the LIGA process using a Si-Au mask. We propose to use PMMA molds both as the mechanical structure and as the insulator between electrodes. We believe there are great opportunity for the LIGA process in making micro actuators of HDDs. Received: 25 August 1997 / Accepted: 24 October 1997     

V830R/AV: embedded multimedia superscalar RISC processor

The V830R/AV's real-time decoding of MPEG-2 video and audio data enables practical embedded-processor-based multimedia systems     

Synthesis and Some Properties of Panulose. A New Keto-Oligosaccharide

During the studies on the transformation of oligosaccharides in alkaline solution, we obtained a new keto-trisaccharide. This oligosaccharide was obtained by the Lobry de Bruyne-Alberda van Ekenstein transformation of panose. The new saccharide was separated from panose by paper chromatography and cellulose column chromatography using the solvent system containing boric acid. The trisaccharide contains one mole of fructose moiety in its structure. The results of the partial hydrolysis by acids and enzymes suggested the structure of 6²-α-glucosyl maltulose 0-α-D -glucopyranosyl-(1→6)-0-α-D -Glucopyranosyl-(1→4)-D -Fructosel. The novel saccharide was named panulose, as this was obtained by the isomerization of panose.     

Advances in Digital Front-End and Software RF Processing： Part II

In the first editorial of this two-part special issue, we pointed out that one of the biggest trends in wireless broadband, radar, sonar, and broadcasting technology is software RF processing and digital front-end [1]. This     

Arraying needle-like TiO2 particles in a composite film by applying ac bias and its transmittance anisotropy

In an effort to improve energy-efficient windows, we experimented with a precursor slurry composite by using needle-like TiO₂ particles as the filler in a urethane matrix. Applying dc bias to the slurry failed to array the needle-like particles in the composite and to deposit on the film surface because of electrophoretic movement. However, applying ac bias of ±5 V to the precursor slurry composite for 12 h resulted in the needle-like TiO₂ particles being arrayed in the composite in a direction normal to the film surface. This resulted in an improvement in the energy efficiency of the material through an angular dependence of transmittance in the visible–near-infrared range.     

GPC Profile Change of Potato Starch with Extrusion Processing

Native potato starch (moisture content 15%) was treated by twin screw extruder under four operating conditions with varying barrel temperatures (110°C–230°C). These modified starch samples were compared to native and drum-dried starch. Starch sample solution for gel chromatography was prepared by the three methods (acidic, alkaline, and neutral methods). They were subjected to gel chromatography on Toyopearl HW-75, and some difference was found among the three gel chromatographic patterns obtained from the same starch solution. This discrepancy among GPC patterns suggests formation of some types of anhydro-bonds between chains of amylopectin and or amylose in the extrusion process. Elevating barrel temperature increases degree of depolymerization. The size of fragments formed with the treatment is bigger than that of oligosaccharides but smaller than that of amylose.     

Scaling theory for double-gate SOI MOSFET's

A scaling theory for double-gate SOI MOSFETs, which gives guidance for device design (silicon thickness t_si; gate oxide thickness t_ox) that maintains a subthreshold factor for a given gate length is discussed. According to the theory, a device can be designed with a gate length of less than 0.1 μm while maintaining the ideal subthreshold factor. This is verified numerically with a two-dimensional device simulator     

The high-speed limit of FM response in semiconductor lasers

The high-speed frequency modulation (FM) response has been investigated through rate equation analysis. The intrinsic limit of FM response has been found to be given by the product of FM efficiency, η_FM, and the FM bandwidth, B. This relation shows that a wide FM bandwidth means a small FM efficiency. Although the FM efficiency changes with the differential gain or the nonlinear gain coefficient, η_FMB is almost constant. The value of η _FMB was about 5 GHz²/mA for 1.5-μm InGaAsP/InP lasers with 300-μm cavity length. This limit has been confirmed experimentally     

A circuit technology for high-speed battery-operated 16-Mb CMOSDRAM's

A battery-operated 16-Mb CMOS DRAM with address multiplexing has been developed by using an existing 0.5-μm CMOS technology. It can access data in 36 ns when powered from a 1.8-V battery-source, and 20 ns at 3.3 V. However, this device requires a mere 57 mA of operating current for an 80-ns cycle time and only 5 μA of standby current at 3.3 V. To achieve both high-speed and low-power operation, the following four circuit techniques have been developed: 1) a parallel column access redundancy (PCAR) scheme coupled with a current sensing address comparator (CSAC), 2) an N&PMOS cross-coupled read-bus-amplifier (NPCA), 3) a gate isolated sense amplifier (GISA) with low V_T, and 4) a layout that minimizes the length of the signal path by employing the lead on chip (LOC) assembly technique     

Fabrication of 64×64 arrayed-waveguide grating multiplexer onsilicon

A 64 channel arrayed-waveguide multiplexer with 0.4 nm (50 GHz) channel spacing at 1.55 μm has been fabricated using SiO₂-Si waveguides. The authors obtained a crosstalk of less than -27 dB to neighbouring and all other channels. The on-chip insertion loss ranges from 3.1 to 5.7 dB for central and peripheral output ports, respectively