W-band divide-by-3 frequency divider using 0.1 /spl mu/m InAlAs/InGaAs metamorphic HEMT technology

A W-band divide-by-3 frequency divider with wide bandwidth and low power dissipation is presented using harmonic injection-locking technique. A cascode FET is employed for a self-oscillating second-harmonic mixer which is injection-locked by third-harmonic input to obtain the division order of three. The fabricated frequency divider using 0.1 /spl mu/m GaAs metamorphic HEMT technology shows superior performance such as large bandwidth of 6.1 GHz around 83.1 GHz (7.3%) under small DC power consumption of 12 mW.     

A 0.6–2.7 GHz Semidynamic Frequency Divide-by-3 Utilizing Wideband RC Polyphase Filter in 0.18 $mu$m CMOS

A wideband complementary metal oxide semiconductor (CMOS) semidynamic frequency divide-by-3 covering more than two octave bandwidths is presented. The wideband operation without requiring a quadrature signal source is realized by employing a three-stage RC polyphase filter. The transfer function analysis on Type-II two- and three-stage polyphase filters is performed to provide analytic solutions of the peak phase error and peak attenuation. Implemented in 0.18 mum CMOS, the divide-by-3 operates over the input frequency range between 0.6 and 2.7 GHz while dissipating 15 mA from a 1.8 V supply.     

Production and structural features of a water-soluble polysaccharide from a mutant strain of Agrobacterium sp.

We have developed a mutant strain derived from Agrobacterium sp. ATCC 31750, which produces a water-soluble polysaccharide having potential utility to the food, feed, pharmaceutical and cosmetic industries. A high concentration of product (15 g/L) is obtained by 48 h cultivation of the mutant strain under optimized fermentation conditions. The water-soluble polysaccharide obtained from cultures of the mutant strain beta82 has Glc:Man:Gal in approximate molar ratios of 5.8:6.7:1.0. The molecular weight of the polysaccharide was determined to be approximately 1000 kDa by HPSEC analysis. Linkage analysis contained 3-Glcp, 3-Manp, terminal Glcp and terminal Manp, as well as a small proportion of 3- and 3,4-Galp, and 4,6-Manp residues. Based on analyses using FT-IR and ¹³C NMR spectrometers, most glycosidic bonds joining these sugar residues are of the α-type, and acetyl groups are apparently attached to the polymer chain at random.     

Dye adsorption characteristics of alginate/polyaspartate hydrogels

This study examined the removal of some basic dyes, such as Methylene Blue, Malachite Green and Methyl Orange, using alginate or alginate/polyaspartate composite gel beads. The adsorption of dyes from aqueous solutions at 25 °C was examined using a batch sorption technique. The effects of CaCl₂ and the dye concentration on the adsorption were examined. Type-S adsorption isotherms were obtained, which is characteristic of a weak solute–solid interaction. The ionic interaction between the dye molecule and gel matrix appears to be responsible for the efficient adsorption of cationic dyes in this system. These results suggest that an alginate/polyaspartate gel can be used as an effective sorbent for water pollutants such as dyes, and the immobilization of these organic contaminants in the hydrogels from wastewater can solve one of the most important environmental problems in the related industry.     

The relationship between photo-catalytic performance and optical property over Si-incorporated TiO2

This study focuses on the relationship between photo-catalytic performance and optical property over Si-incorporated TiO₂. The Si-incorporated TiO₂ particles exhibited a pure structure of anatase having a particle size of less than 20 nm and surface area of more than 190 m²/g. The absorbance did not shift to a higher wavelength in spite of the incorporation of the Si ions, but the intensity of the photoluminescence (PL) curve was the smallest in the case of the 2.0 mol% Si-TiO₂, which was related to the recombination between the excited electrons and holes. Based on these results, the photodecomposition of methyl orange in the liquid reaction was enhanced over the 2.0 mol% Si-incorporated TiO₂ compared with that over pure TiO₂: Methyl orange at 10.0 ppm was completely decomposed after 100 min when 1.0 g of the 2.0 mol% Si-incorporated TiO₂ was used.     

A Web-based Kanban system for job dispatching, tracking, and performance monitoring

A Kanban system facilitates lean principles in a simple and effective way. While reportedly successful in many manufacturing firms, the conventional Kanban systems using physical cards suffer from human errors, limited tracking capability, and so on. To make the information flow leaner, software providers add new features to their existing programs for manufacturing systems to computerize Kanban activities. As Web-based technologies advance rapidly, developing an entirely Web-based Kanban system appears to be feasible and promising. This paper presents the advantages, limitations, and challenges of Web-based Kanban systems. An experimental program has been developed based on PHP+MySQL, a popular Web programming platform. The server-executed program features cross-platform compatibility, real-time tracking and performance monitoring, and greatly enhanced information contents compared to physical Kanbans. Human errors are minimized by the automated transactions; nevertheless, the interfacing and data maintenance require further research efforts.     

Noise–Power Optimization of Incremental Data Converters

Incremental data converters (IDCs) are useful in instrumentation and measurement applications, where low-frequency analog signals need to be converted into digital form with high accuracy and low power dissipation. They are particularly well suited for applications where a single analog-digital converter is multiplexed between many channels. This paper proposes an exact design methodology for IDCs, which optimizes the signal-to-noise ratio of the converter under practical design constraints. The process also allows the designer to apportion the noise budget in an arbitrary manner between thermal and quantization noise. The design process is illustrated by an example which describes the optimization of a third-order multiplexed IDC.     

Prediction and quality control of the melt index during production of high-density polyethylene

In polyolefin processes the melt index (MI) is the most important control variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the 1 ^st -order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. The virtual sensor model developed based on the estimation scheme was combined with the virtual on-line analyzer (VOA) to give a quality control system to be implemented in the actual HDPE plant. From the application of the present control system, significant reduction of transition time and the amount of off-spec during grade changes was achieved