Fuzzy Linear Programming with Interactive Uncertain Parameters

In this paper, we treat fuzzy linear programming problems with uncertain parameters whose ranges are specified as fuzzy polytopes. The problem is formulated based on fractile optimization model using a necessity measure. It is shown that the problem can be reduced to a semi-infinite linear programming problem and that a solution algorithm based on a relaxation procedure can be applied. A simple numerical example is given to illustrate the solution procedure. This revised version was published online in June 2006 with corrections to the Cover Date.     

Maskless Lateral Epitaxial Growth of Gallium Nitride Using Dimethylhydrazine as a Nitrogen Precursor

Lateral epitaxial growth (LEG) is a key technology to improve the lifetime of III-V nitride-based laser diodes (LDs) by reducing the dislocation density in the materials. To increase the area of low dislocation density, the lateral growth rate needs to be increased. In addition, suppression of the vertical growth is strongly desired to avoid unnecessarily thick growth, which would result in cracks in the epitaxial film. This paper reports the maskless LEG of GaN with extremely high lateral-to-vertical growth rate ratio using dimethylhydrazine as a nitrogen precursor. The lateral growth only occurs from the sidewalls of the etched mesa stripes without any dielectric masks. The lateral growth rate toward the direction is extremely high, as high as 10 μm/h, while no vertical growth is observed on the top of unmasked mesa. The cross-sectional transmission electron microscopic image shows that the threading dislocations in the wing region extend only toward the lateral direction. Note that almost smooth coalescence between the wing regions is confirmed by atomic force microscopy. X-ray diffraction measurements reveal that this maskless LEG drastically improves the crystallographic twist down to 97 arc-s, which is as comparably low as that of a free-standing GaN substrate. The presented maskless LEG is advantageous for optical device applications.     

Self‐Tuning PI Control Using Adaptive PSO of a Web Transport System with Overlapping Decentralized Control

Web transport systems for transporting films, textile material, paper, etc., are usually large‐scale systems. The velocity and the tension of the web are controlled by dividing the systems into several subsystems in which strong coupling exists between the velocity and tension control. A self‐tuning PI (STPI) controller with an estimator based on a novel adaptive particle swarm optimization method is constructed, and it is applied for controlling an actual web transport system. The controllers are designed on the basis of the methodology of the overlapping decentralized control by taking into consideration online executions performed by a general computer. The effectiveness of the constructed control system is verified on the basis of several experimental results obtained by using an actual experimental web transport system. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 184(1): 56–65, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22366     

Purification and characterisation of basic ascorbate oxidase from satsuma mandarin (Citrus unshiu Marc)

Basic ascorbate oxidase of the multiple enzyme forms existing in young fruit of satsuma mandarin (Citrus unshiu Marc) has been separated and subsequently purified to electrophoretic homogeneity through (NH₄)₂SO₄ fractionation and chromatographies on DEAE-Toyopearl 650M, CM-Sephadex C-50 and Sephadex G-100. The native molecular weight was estimated to be 141 kDa by gel filtration and composed of two non-identical subunits with an apparent mass of 74 kDa and 62 kDa. The optimum pH was found to be 5.5 with reasonable stability between pH 5 and 8. The enzyme had an optimum temperature at 45°C and was stable up to 50°C upon heat treatment for 5 min. The presence of sodium diethyldithiocarbamate, metabisulphite and potassium cyanide completely inhibited the enzyme activity. Fluoride also inhibited the activity substantially at higher concentrations. Other tnonovalent and divalent metal ions did not have inhibitory effects.     

Oxidation of Methyl Linoleate in Oil-in-Water Micro- and Nanoemulsion Systems

Oxidation of methyl linoleate in O/W emulsions having droplets of median diameters ranging from 17 nm to 8.0 μm was carried out at 40°C. The oxidation process was analyzed on the basis of a kinetic equation of the autocatalytic type. The induction period was found to be shorter and the oxidation rate constant lower for emulsions with smaller oil droplets. The stoichiometry between methyl linoleate and oxygen was observed to be independent of both the size of oil droplet and the type of the surfactant and was found to be unity during the early stage of the oxidation. However, more oxgen was consumed in the oxidation of the methyl linoleate in the later half of the oxidation process.     

Purification and properties of polyphenol oxidase in head lettuce (Lactuca sativa)

Polyphenol oxidase (EC 1.10.3.1) in head lettuce (Lactuca sativa L) was purified by ammonium sulphate fractionation, ion exchange chromatography and gel filtration. The enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be about 56 000 amu by Sephadex G-100 gel filtration. The purified enzyme quickly oxidised chlorogenic acid (5-caffeoyl quinic acid) and (—)-epicatechin. The K^m values for the enzyme, using chlorogenic acid (pH 4·5, 30°C) and (—)-epicatechin (pH 7·0, 30°C) as substrate, were 0·67 mM and 0·91 mM, respectively. The optimal pH of chlorogenic acid oxidase and (—)-epicatechin oxidase activities were 4·5 and 7·8, respectively, and both activities were stable in the pH range 6–8 at 5°C for 20 h. Potassium cyanide and sodium diethyldithiocarbamate markedly inhibited both activities of the purified enzyme. The inhibitory effect of metallic ions such as Ca²⁺, Mn²⁺, Co²⁺ and Ni²⁺ for chlorogenic acid oxidase activity was stronger than that for (—)-epicatechin oxidase activity.     

Simulation of cross-talk reduction in multimode waveguide-based micro-optical switching systems by use of single-mode filters

We propose a method to reduce cross talk by using single-mode filters, namely, extracting the fundamental mode from a multimode optical network (EFMON). The EFMON effect is evaluated for a three-step switching system consisting of cascade electro-optic (EO) waveguide prism deflector (WPD) micro-optical switches (MOSs) and a multimode waveguide network. The WPD MOS is optimized for single-mode operation in lead lanthanum zirconate titanate thin films as EO slab waveguides with a driving voltage of 12 V, a length of 310 microm, and a channel distance of 20 microm. Beam propagation method simulation reveals that mode disturbance, higher-order modes, and cross talk are accumulated by switching steps. A single-mode filter for EFMON in the output region of the switching system reduces cross talk to below -20 dB at a propagation length of 2000 microm in the single-mode filter and below -30 dB at 20000 microm.