Electron-beam writing system and its application to large and high-density diffractive optic elements

An electron-beam writing system that is chartacterized by a stationary electron beam and a continuously spinning table is proposed and developed for diffractive optic elements with axisymmetric patterns. This system allows us to fabricate continuously concentric or radialized high-density microgratings with effective areas over the electron-beam deflection limits. For a fine electron-dose distribution, we adopted multiple-revolution writing and electron-beam modulation. Several test gratings, including a rotary encoder disk with a 1.57-μm grating pitch and a 15-mm diameter and a blazed micro-Fresnel lens with a 4.5-mm diameter and a N.A. of 0.45, are successfully demonstrated with real-time data processing.     

Ultra‐low‐power polysilicon AMLCD with full integration

Abstract— An LTPS TFT‐LCD that only consumes 0.07 mW of power was developed. It is the world's first LCD equipped with all the circuits needed to display still images continuously for up to 1 year on a button battery. At the same time, the panel is capable of displaying 260,000‐color moving pictures.     

Thermal design of plastic LSI packages with fins

As a result of recent progress in electronic equipment and devices, the power dissipation of LSI chips has tended to increase. Therefore, it has become more important to improve their heat transfer characteristic. Methods already used to enhance heat transfer in manufactured packages involve adding a heatspreader or using heat radiating lead-frames. In this paper, we propose two kinds of thermally improved packaging designs. One has molded plastic fins on the top of the surface. The other has lead-frame fins that extend from the heat radiation lead-frames. We designed these thermal structures using a previously reported thermal resistance analysis of LSI packages, and then built trial models and measured their thermal resistance by suspending them in a wind tunnel. According to the measurements, the thermal resistance of the package with plastic fins is about 34 percent lower than that of a fin-less package, and the resistance of the package with lead-frame fins is about 20 percent lower than that of a package with only radiation leads. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(6): 382–399, 1996     

Color segmentation for text extraction

The capability of extracting and recognizing characters printed in color documents will widen immensely the applications of OCR systems. This paper describes a new method of color segmentation to extract character areas from a color document. At first glance, the characters seem to be printed in a single color, but actual measurements reveal that the color image has a distribution of components. Compared with clustering algorithms, our method prevents oversegmentation and fusion with the background while maintaining real-time usability. It extracts the representative colors based on a histogram analysis of the color space. Our method also contains a selective local color averaging technique that removes the problem of mesh noise on high-resolution color images.Received: 25 July 2003, Revised: 10 August 2003, Published online: 6 February 2004Correspondence to: Hiroyuki Hase. Current address: 3-9-1 Bunkyo, Fukui-shi 910-8507, Japan     

Heavy metals in emergent trees and pioneers from tropical forest with special reference to forest fires and local pollution sources in Sarawak, Malaysia

Leaf samples of tropical trees, i.e. Dryobalanops lanceolata (Kapur paji), Dipterocarpaceae and Macaranga spp. (Mahang), Euphorbiaceae were analyzed for 21 chemical elements. The pioneer Macaranga spp. exhibited higher concentrations for the majority of elements compared to the emergent species of Dryobalanops lanceolata, which was attributed to the higher physiological activity of the fast growing pioneer species compared to emergent trees. Lead showed rather high concentrations in several samples from the Bakam re-forestation site. This is suggested to be caused by emissions through brick manufacturing and related activities in the vicinity. A comparison of Dryobalanops lanceolata samples collected in 1993, 1995 and 1997 in the Lambir Hills National Park revealed that certain heavy metals, i.e. Co, Cu, Mn, Ni, Pb and Ti showed higher values in 1997 compared to the previous years, which could indicate an atmospheric input from the haze caused by the extensive forest fires raging in Borneo and other parts of Southeast Asia.     

Identification of volatile selenium compounds produced in the hydride generation system from organoselenium compounds

We report a novel aqueous derivatization of selenomethionine (Semet), selenoethionine (Seet) and trimethylselenonium ion (TmSe) by NaBH4 and HCI to volatile selenium species, namely, diethyldiselenide (DeDSe), dimethyldiselenide (DMDSe), dimethylselenide (DmSe) and ethylhydrogenselenide (ESeH), in the hydride generation (HG) system. The volatile selenium compounds produced in the HG system were on-line trapped and concentrated in a U-tube that was immersed in the liquid nitrogen trap. The trapped volatile Se compounds were volatilized at 80 degrees C in a water bath, and 50-500 microL of volatile gas was injected into the GC/AED and GC/MS, respectively. It has been established that DmSe, DmDSe, and DeDSe are the predominant Se compounds that are produced in the HG system from TmSe, Semet, and Seet, respectively, followed by ESeH from Seet. Analytical methods previously employed have stated that these compounds are inactive in the HG system. Prior decomposition of Semet, Seet, and TmSe to selenous acid is essential before HG. To the best of our knowledge, current findings for the production and identification of volatile selenium compounds in the HG system are new and different from existing reports; hence, direct estimation of Semet, Seet, and TmSe is possible when coupling with a HG system using a suitable Se-specific detector.