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Articles 25891 - 25920 of 27331

Full-Text Articles in Engineering

Bs News Sep 1997

Bs News

Building Services Engineering

No abstract provided.

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Corrosion Behaviour Of Copper Covered With Ion Selective Phenolic Coatings By Eis, Zhoucheng Wang, Yingzhou Zhang, Shaomin Zhou Aug 1997

Corrosion Behaviour Of Copper Covered With Ion Selective Phenolic Coatings By Eis, Zhoucheng Wang, Yingzhou Zhang, Shaomin Zhou

Journal of Electrochemistry

Electrochemical impedance spectroscopy(EIS) technique was employed to study the corrosion behaviour of copper painted with the anion selective, cation selective and bipolar phenolic coatings in 3% NaCl solution. From the impedance spectrum characteristics, the models of equivalent circuit for these different coating systems were established, and the methods for the analysis of experimental impedance diagrams in terms of coating and interface properties were discussed. The research results show that the composition and structure of ion selective coatings have significant influence on corrosion behaviour of copper. The bipolar coating consisting of an anion selective inner layer and a cation selective outer …

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Preparation Of Pbo2/Ti Plate Electrode, Zhigang Shao, Baolian Yi, Xinge Zhang, Enjun Zhang Aug 1997

Preparation Of Pbo2/Ti Plate Electrode, Zhigang Shao, Baolian Yi, Xinge Zhang, Enjun Zhang

Journal of Electrochemistry

The perchlorate was made up of a lead dioxide plate elcetrode and an oxygen cathode. By measuring the flow capacity of cell gas in the cell, and by means of CV, SEM, XRD, the performances of the lead dioxide plate electrodes are evaluated. The influence of changes in the concentrations of electroplating solutions (F, HNO3, Bi3+, Ni2+, Fe3+ and surface active agent) is investigated. The results show that the concentrations of Fe3+ in the solutions must be lower 0.01 g/L, and the concentrations of HNO3 in the solutions are about 20 …

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Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅲ. Improvement Of Artificially Imposed Solid Electrolyte Film On Cell Performance, Shuhua Ma, Xiabin Jing, Fosong Wang Aug 1997

Surface Modifications Of Carbon Materials Used As Anode Of Lithium Ion Battery Ⅲ. Improvement Of Artificially Imposed Solid Electrolyte Film On Cell Performance, Shuhua Ma, Xiabin Jing, Fosong Wang

Journal of Electrochemistry

The improving effect of solid electrolyte film artificially imposed on carbon electrode was investigated. The result showed that both the charge/discharge capacity and first charge/discharge efficiency, to a certain extent, were enhanced, and the result also suggested the effectiveness of the substitution of the artificially imposed solid electrolyte film for the inherent passivating film which was formed on the surface of the carbon electrode while inserted in the electrolyte during charging or discharging. The Scanning Electron Microscope result displayed the compact and well-defined morphology of the artificially imposed crystalline film.

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Preparation And Examination Of Planar Type Solid Oxide Fuel Cells, Yi Jiang, Jingwang Yan, Shizhong Wang, Chunying Yu, Wenzhao Li Aug 1997

Preparation And Examination Of Planar Type Solid Oxide Fuel Cells, Yi Jiang, Jingwang Yan, Shizhong Wang, Chunying Yu, Wenzhao Li

Journal of Electrochemistry

The solid oxide fuel cells of planar type (SOFC) have been developed after successfully preparing La0.8Sr0.2MnO3 cathodes and Ni-YSZ ceramic anodes on YSZ plates and solving the high temperature sealing technical problem. Examination of the single cells fabricated showed that the maximum power output at 950 ℃ for H2 as fuel and air as oxidant reached 0.12 W/cm2. It was found that the large polarization overpotential of the Ni-YSZ anode and the Ohmic losses of the cells were two main factors responsible for the relative low output power density.

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Electrorheological Characters Of Polyaniline Suspensions, Guangyao Su, Deshu Gao, Changqing Zhang Aug 1997

Electrorheological Characters Of Polyaniline Suspensions, Guangyao Su, Deshu Gao, Changqing Zhang

Journal of Electrochemistry

Polyaniline (PAn) as the dispersive particles and insulating oil as the dispersive medium, the electrorheological fluid (ERF) is constituted. Relations between the factors of electric field strength (E), temperature (T) and the static yield stress (τS), current density (i) of ERF are investigated. The results show that the changes of τS and i with electric field intensity have emerged in the exponential relation, i.e, τS∝E0.7, i∝E2.18. Otherwise, when exert a constant voltage on ERF, owing to the polarization, the absorption of medium of ERF have taken place. Therefore, the attenuation rate …

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Study On The Diffusion Of Electroactive Molecules In Polymer Electrolyte By Microelectrode Voltammetry, Liming Ding, Shaojun Dong, Erkang Wang Aug 1997

Study On The Diffusion Of Electroactive Molecules In Polymer Electrolyte By Microelectrode Voltammetry, Liming Ding, Shaojun Dong, Erkang Wang

Journal of Electrochemistry

The ten years study on the diffusion of electroactive molecules in polymer electrolyte by microelectrode voltammetry was reviewed by considering the development background of polymer electrolyte materials. The classification, fabrication, applications and electrochemical measurements of microelectrode were introduced concisely. The several important factors influencing the diffusion of electroactive molecules were stressed. In the final part of this paper, some new reports on the diffusion of labeled molecules were introduced.

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Behavior Of Copper In Hydrogen Storage Alloy Microencapsulated By Copper, Dawei Zhang, Huatang Yuan, Huabin Yang, Zuoxiang Zhou, Yunshi Zhang Aug 1997

Behavior Of Copper In Hydrogen Storage Alloy Microencapsulated By Copper, Dawei Zhang, Huatang Yuan, Huabin Yang, Zuoxiang Zhou, Yunshi Zhang

Journal of Electrochemistry

Negative electrode made from Cu microencapsulated hydrogen storage alloy was studied by using cyclic voltammetry method. The results showed that copper as a coating material was of a certain stability in 5 mol/L KOH solution within the range of charge and discharge voltage. But when expanding the sweep voltage, the CV curve showed a pair of distinct oxidation reduction current peaks of Cu2O formation at E = -0.3 V and Cu2O reduction at E =-0.6 V. With charging discharging cycles, copper is liable to be oxidized to Cu2O and further oxidized into CuO2 …

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Electrocatalytic Oxidation Of Methanol On The Stearate Nickel L-B Film, Benzeng Hua, Wenyan Hu, Yanzhen Chen, Yanhong Zhang Aug 1997

Electrocatalytic Oxidation Of Methanol On The Stearate Nickel L-B Film, Benzeng Hua, Wenyan Hu, Yanzhen Chen, Yanhong Zhang

Journal of Electrochemistry

The stearate nickel L-B films is good electroacatlyst for the oxidation of methanol MeOH in alkaline. The electrochemical behaviors of stearate nickel L-B films is affected by the concentration of KOH. The rate of quantity of mickel ion and stearic acid in L-B films is 1∶1, which means that the nickel ion may exist in -COONi(OH) form. The electrocatalytic process is influenced by the concentration of OH-, it involves the penetration of MeOH into the films. The oxidative currents of MeOH are linearly dependent on the bulk concentration.

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Study On Electrochemical Methods Of Controlled Convolution ——A Simple Electron Transfer Reaction Followed By A Homogeneous Catalytic Reaction(Ⅰ), Ming Ma, Naixian Xie, Qianlei Gao, Yue Zeng Aug 1997

Study On Electrochemical Methods Of Controlled Convolution ——A Simple Electron Transfer Reaction Followed By A Homogeneous Catalytic Reaction(Ⅰ), Ming Ma, Naixian Xie, Qianlei Gao, Yue Zeng

Journal of Electrochemistry

A simple electron transfer reaction followed by a homogeneous catalytic reaction is studied in this paper by three kinds of controlled convolution electrochemical experimental methods, which are the constant semi integral (CSI), linear semi integral sweep (LSIS) and linear semi differential sweep (LSDS). According to the three methods, the following equations can be obtained. With these equations, the theoretical curves of the above three methods can be computed. Experiments of the ferrocyanide ascorbic acid catalytic system have confirmed that kinetic rate constant in catalytic reaction is in good agreement with the previously reported values.

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Investigation On Electro Reduction Behaviour Of Copper Anodic Products In Concentrated Naoh Solutions Ⅱ. Electro Reduction Of Cu(Ⅱ) Products, Jianbo He, Hanhe Chen, Jianxin Lin Aug 1997

Investigation On Electro Reduction Behaviour Of Copper Anodic Products In Concentrated Naoh Solutions Ⅱ. Electro Reduction Of Cu(Ⅱ) Products, Jianbo He, Hanhe Chen, Jianxin Lin

Journal of Electrochemistry

Potentiostatic oxidation potentiodynamic or galvanostatic reduction methods have been used to study the cathodic reduction behaviour of various products anodically formed on the second stage of copper oxidation in concentrated NaOH solutions. Seven cathodic current peaks and the corresponding cathodic potential plateaus are observed on the potentiodynamic E/i curves and the galvanostatic E/t curves, respectively. In the negative potential scan, there are three couples of voltammetric peaks which have been attributed to the formation and reduction of CuO, Cu(OH)2 and Cu(Ⅱ) ion, respectively. The complicated mechanism for the electro formation of the three Cu(Ⅱ) species are discussed.

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Studies On The Failure Modes Of Stationary Vrla Batteries, Yibo Tong, Xiangming Qiu Aug 1997

Studies On The Failure Modes Of Stationary Vrla Batteries, Yibo Tong, Xiangming Qiu

Journal of Electrochemistry

In order to improve the reliability and the quality of stationary valve-regulated lead-acid (VRLA) batteries, the failure modes of the stationary VRLA batteries which caused by the water loss and the thermal runaway are studied. The water loss may be solved by increasing the Oxygen-recombination efficiency, choosing the suitable grid material and the additives of megative paste, decreasing the corrosion of the positive plates. The thermal runaway may be solved by decreasing the inner ohmic resistance of VRLA batteries, improving the outside condition of batteries such as putting into the absorbing-heat material between the abtteries etc..

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The Electrochemical Behavior And Deposited Mechanism Of Zn-Ni Alloy Codeposition, Jixun Wu, Yongqin Liu, Huimin Meng Aug 1997

The Electrochemical Behavior And Deposited Mechanism Of Zn-Ni Alloy Codeposition, Jixun Wu, Yongqin Liu, Huimin Meng

Journal of Electrochemistry

The electrochemical behavior of Zn-Ni alloy codeposition and concomitant hydrogen evolution have been studied in the chloride ammonia solution through the d-c electroplating method. Under the condition of the applied cathodic current density of 2A/dm2 , the AC impedance spectra have been measured. An equivalent circuit has been presented for the impedance study on the alloy codeposition.

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The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen Aug 1997

The Electrode Process Of Some Organic Dyes Studied By Spectroelectrochemical Technique In Situ, Yinxuan Tang, Hangsheng Yang, Baoen Shen

Journal of Electrochemistry

Spectroelectrochemistry especially with in situ measurement in a cell provides a very useful mthodology for measuring the parameters of electrode process. In this paper, we report the determination of formal potentials, the number of electron transfer, the diffusion coefficient, the heterogeneous electron transfer rate constant and the transfer coefficient of some organic dyes (Methyelene blue, Neutral red, Indigo carmine) using spectroelectro chemical technique in situ.

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Do Not As I Say And Not As I Do: The Problem Of Tritium, Ibpp Editor Aug 1997

Do Not As I Say And Not As I Do: The Problem Of Tritium, Ibpp Editor

International Bulletin of Political Psychology

The author discusses the manufacture and use of tritium for nuclear warheads.

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39th Rocky Mountain Conference On Analytical Chemistry Aug 1997

39th Rocky Mountain Conference On Analytical Chemistry

Rocky Mountain Conference on Magnetic Resonance

Preliminary program and registration information for the 39th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 3-7, 1997.

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Trends. Political Psychology In Space: Diagnostic Issues, Ibpp Editor Jul 1997

Trends. Political Psychology In Space: Diagnostic Issues, Ibpp Editor

International Bulletin of Political Psychology

The author discusses the nomenclature, standards, and criteria are most optimal to evaluate space station personnel.

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Trends. Supercomputer Sales And Nuclear Proliferation: The Surrealist Top Ten, Ibpp Editor Jul 1997

Trends. Supercomputer Sales And Nuclear Proliferation: The Surrealist Top Ten, Ibpp Editor

International Bulletin of Political Psychology

The author discusses supercomputers in conjunction with nuclear weapons.

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Bs News Jul 1997

Bs News

Building Services Engineering

No abstract provided.

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Aerospace And Foreign Policy, Ibpp Editor Jun 1997

Aerospace And Foreign Policy, Ibpp Editor

International Bulletin of Political Psychology

The author discusses developing and implementing foreign policy towards the Peoples Republic of China regarding the market for aircraft and aerospace technology.

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Analysis Of Design Wind Speed Distribution Of Taiwan Area, Jing-Jong Jang, Jeng-Ru Lee Jun 1997

Analysis Of Design Wind Speed Distribution Of Taiwan Area, Jing-Jong Jang, Jeng-Ru Lee

Journal of Marine Science and Technology–Taiwan

This paper thoroughly examines the basic design wind speed according to wind loading of building codes in Taiwan. The first part of this study contains Chi-Square test and K-S (Kolmogorov Smirnov) test on four common wind speed probability distribution models. The data to be tested are sampled from the annual maximum 10-minute average wind speed recorded by 25 weather stations of Taiwan Central Weather Bureau during the period from 1951 to 1990. The Type I Extreme Value model is determined and recommended as the best wind speed probability distribution model for Taiwan area. This paper then explores the probability of …

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On The Rigid-Ideally Plastic Deformation Of Cantilever Bean Subjected To Tip Impact, Ming-Te Liang, Bon-Jofei Lee, Sen-Shyang Yang Jun 1997

On The Rigid-Ideally Plastic Deformation Of Cantilever Bean Subjected To Tip Impact, Ming-Te Liang, Bon-Jofei Lee, Sen-Shyang Yang

Journal of Marine Science and Technology–Taiwan

This paper presents to study the resemblance and discrepancy between the rigid-plastic and elastic-plastic deformation of cantilever beams subjected to tip impact. For this, the theory of Ting's analysis [3] and calculation parameter obtained from Parkes [1] and Symonds and Fleming [4] are used for numerical computation. These results obtained from rigid-plastic deformation are compared with those results calculated by Reid and Gui [8] who used the non-linear finite-clement code ABAQUS for presenting the numerical solution of the elastic-plastic deformation of cantilever beams. No matter what rigid-plastic or elastic-plastic deformation, the kink phenomena of the plastic hinge arrest mechanism is …

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On Parametric Pole-Placement For A Class Of Linear Systems, Jeng Yih Juang Jun 1997

On Parametric Pole-Placement For A Class Of Linear Systems, Jeng Yih Juang

Journal of Marine Science and Technology–Taiwan

This paper presents an innovative approach for parametrizing a class of state-feedback pole-placement controllers through the minimum number of effective free parameters. The approach is based on the theory of hypothetical loop-decoupling. Linear and nonlinear functions of parameter coupling in the feedback gain matrices are disclosed to the problem of generic parametric poleplacement for a linear time-invariant controllable system. With the class depicted by the controllability indices for the hypothetical control loops, parametrization for state-feedback design can be achieved. The flexibility in loop pole-assignment for a multi-input system also affects the choice for the gain matrix. The excellence of the …

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The Application Of Wavelet-Based Least Mean Square Algorithm In Adaptive Beamforming, Shun-Hsyung Chang, Chin-Chang Chang Jun 1997

The Application Of Wavelet-Based Least Mean Square Algorithm In Adaptive Beamforming, Shun-Hsyung Chang, Chin-Chang Chang

Journal of Marine Science and Technology–Taiwan

Wavelet transform is one of methods that utilizes the dilation and contraction of prototype wavelet basis function to form a set of fully flexible windows in the time-frequency plane. It exhibits a good effect in both the analysis of high and low frequency components of signal. By applying such a transform method to traditional least-mean-square algorithm (LMS), we can obtain an orthogonally transformed signal from a time-domain input signal after imposing wavelet transform on it. In addition, we can improve the convergence speed of learning curve by passing the transformed signal through weight which is adapted with LMS. The improved …

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Application Of Decomposition Technique To Linear Wave Model Identification, Ching-Yaw Tzeng Jun 1997

Application Of Decomposition Technique To Linear Wave Model Identification, Ching-Yaw Tzeng

Journal of Marine Science and Technology–Taiwan

A decomposition technique is employed in identifying the coefficients of a Fourier series-based linear wave model. Two decomposed subproblems are formulated, one in the frequency domain and one in the direction domain. Less computation time is required when solving the two subproblems sequentially, compare to solving the original problem directly. A stretched method that takes the instantaneous free surface as the reference position in computing the water particle velocities achieves better agreement with the experimental data than the standard linear approach where the reference position is taken at the mean water level.

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The Effect Of Aggregate Volume Ratio On The Elastic Modulus And Compressive Strength Of Lightweight Concrete, Chung-Chia Yang, Yung-Shin Yang, Ran Huang Jun 1997

The Effect Of Aggregate Volume Ratio On The Elastic Modulus And Compressive Strength Of Lightweight Concrete, Chung-Chia Yang, Yung-Shin Yang, Ran Huang

Journal of Marine Science and Technology–Taiwan

In order to investigate the effect of aggregate volume ratio (S/A, volume of sand/ volume of total aggregate) on the elastic modulus of lightweight concrete, cylindrical specimens ( 010x200mm) with different S/A ratios and various water-cement ratios were cast and tested. Both single inclusion model and double inclusion model were applied to predict the elastic moduli of two-phase and three-phase cement-based composite materials, respectively. The elastic modulus of lightweight aggregate was obtained based on composite theory models. In this study, the aggregate volume ratio significantly affects the elastic properties of lightweight concrete. The elastic modulus and compressive strength of lightweight …

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Optimum Spacings Of Longitudinal Convective Fin Arrays, Rong-Hua Yeh, Shih-Pin Liaw, Ming Chang Jun 1997

Optimum Spacings Of Longitudinal Convective Fin Arrays, Rong-Hua Yeh, Shih-Pin Liaw, Ming Chang

Journal of Marine Science and Technology–Taiwan

This paper deals with the optimum spacings of longitudinal fin arrays in forced convection theoretically. Four different fins in arrays such as rectangular, convex-parabolic, triangular, and concave-parabolic fins are taken into consideration in the analysis. The aspect ratio, interfin spacing, and heat transfer characteristics of the optimized fin arrays are investigated with given geometry of base plate, total fin volume, and transverse Biot number. A comparison in the total heat duties and overall surface efficiencies of the four different arrays is also made. All the results are presented in dimensionless forms for the convenience of parametric study and design analysis.

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An Experimental Study On Solidification Of Pure Water Or A Dilute Salt Solution In A Horizontal Copper Tube, Hwa-Chong Tien, Sih-Li Chen, Bing-Shiang Yang Jun 1997

An Experimental Study On Solidification Of Pure Water Or A Dilute Salt Solution In A Horizontal Copper Tube, Hwa-Chong Tien, Sih-Li Chen, Bing-Shiang Yang

Journal of Marine Science and Technology–Taiwan

Solidification of pure water and NaCl-HO solutions in a copper tube is investigated experimentally. The morphology and growth of the two phase region is observed photographically, In the experiments of NaCl-H2O solutions, the salt concentrations in the solutions are smaller than the concentration at the eutectic point. The coolant temperature is higher than the eutectic temperature. The supercooling phenomenon and the effects of the coolant temperature, initial temperature of water or NaCl-HzO solution, and the concentrations of the solutions are studied in detail. In addition to the photographs, results presented also nclude the temperature responses of water and NaCl-H2O solutions …

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Constrained Dynamic Controller Design For Ship Steering Yaw-Control, Wen-Jer Chang Jun 1997

Constrained Dynamic Controller Design For Ship Steering Yaw-Control, Wen-Jer Chang

Journal of Marine Science and Technology–Taiwan

Multiple constrained dynamic controller design problems associated with steering of ship yaw motion are discussed in this paper. The multiple constraints considered here contain individual state variance constraints, robust performance (H.. norm) constraints and regional pole assignment (D-stability) constraints. The necessary and sufficient conditions for the existence of the constrained dynamic controller, which achieves the above three constraints, will be derived. Under achieving these conditions, the dynamic controllers will be solved by using the well known singular value decomposition (SVD) techniques and the theory of generalized inverses. Finally, a numerical simulation is given to show the usefulness and applicability of …

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Computerized Shortest Path Searching For Vessels, Gene Eu Jan, Ming-Bo Lin, Yung-Yuan Chen Jun 1997

Computerized Shortest Path Searching For Vessels, Gene Eu Jan, Ming-Bo Lin, Yung-Yuan Chen

Journal of Marine Science and Technology–Taiwan

The solution of "computerized shortest path searching for vessels" is presented in the paper. In the core of the method, the shortest path algorithm on the raster plane with O(N?) time was applied with dedicated database structure and searching rules. Furthermore, we can extend the method to the optimal path searching for Search and Rescue (SAR) and Vessel Traffic Management System (VTMS) by modifying the database and searching rules.

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