Table of Content

20 June 2003, Volume 31 Issue 6

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Form-finding Analysisof Membrane Structures by the Force-density Method 



Wei Demin Li Lianbin Wang Yong

2003, 31(6):  1-4. 

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Membrane structures are the typical tensile structures, whose design method is different from that of ordinary structures. In the design of menmbrane structures, the form-finding analysis is fundamental and necessary. In this paper, the elemental formula of force-density method of the membrane structure are obtained. Computational programs are accomplished. The computational results of some examples and some useful conclusions are given.

Basic Properties of a New-type Concrete Filled Steel Tubular Column-slab Joint



Liufu Jun, Cai Jian, Liu Li-yan, et al

2003, 31(6):  5-9. 

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Measurement Regulation of Several Ancient Korean Buildings



Xiao Min

2003, 31(6):  10-14. 

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By analyzing the data of some ancient Korean buildings, this paper tries to recover the length of the ruler and concludes by deduction a measurement regulation based on a modulus system. It is believed that a module controlled the width, depth and column height of those ancient Korean buildings.

Nonlinear Finite Element Analysis on the New-type Concrete Filled Steel Tubular Column-slab Joint



Tang Min Cai Jian

2003, 31(6):  15-19. 

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Based on the appropriate material constitutive equation, failure criterion and model of cracking and crashing, a 3D nonlinear finite element method (FEM) computative model is presented to further analyze the crack form and mechanical properties of this new-type concrete filled steel tubular column-slab joint on axial compressive condition. Calculation results show that a good agreement between the experimental and analytical results can be obtained.

Horizontal Earthquake Isolating Function of the Vertical Spring-steel Rolling Base Isolation Seismic System



2003, 31(6):  20-25. 

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A new base isolation seismic method of vertical spring-steel rolling base isolation seismic system is proposed, the vibration equations of the base isolation seismic system are established according to the non-variation principle of potential energy and the rule of 'set-in-right-position'. The effect of every control parameter on the system response are analysed. The research results show that the structure of the isolated seismic system is simple and the effect of isolating the horizontal earthquake is optimal.

Modified Adaptive Genetic Algorithm for One-dimensional Cutting Problem



Wei Liangliang Ye Jiawei

2003, 31(6):  26-30. 

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This paper presents a modified adaptive genetic algorithm hybridized with BFD algorithm (MAHGA). A comparison between the MAHGA and a new good method such as EPFF algorithm is made in terms of calculation speed and precision. The result shows that the MAHGA can obtain satisfying effect. One sample is also presented to show the result.

Model Reference Adaptive Control for Permanent Magnet Linear Motor Drives



Chen Yuanrui Wu Jie Norbert C.Cheung

2003, 31(6):  31-35. 

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The simplified mathematical model of the permanent magnet linear motor is deduced in this paper. A model reference adaptive controller is designed by applying the Lyapunov stability theory. Then the controller is evaluated by computer simulation. The results show that the model reference adaptive system (MRAS) is superior to the conventional PID controller in dynamic performance and steady accuracy. The MRAS is robust to the parameter variation and external disturbance.

Sliding Mode Control in the DC-DC Converter and Its Dynamic Quality



Yang Ping, Wu Jie, Liu Mingjian, et al

2003, 31(6):  36-41. 

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This paper provides a design method of the DC-DC converter with a sliding mode control and discusses how to choose switch function S(x) based on the desired output voltage. Meanwhile, the dynamic quality of the sliding mode is analysed and the formula of reaching time is derived. This result can be applied to the design of controllers for DC-DC converters.

Simulation Model of Digital Controller for Three-phase High Power Factor Converter



Zhang Qian Cai Lijuan

2003, 31(6):  42-45. 

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A multi-switch converter with high power factor and its digital control scheme is introduced. A detailed simulation model is set up for its digital controller under MATLAB/SIMULINK. The simulation and experimental results verify the validity of the simulation model and the control scheme, show that the converter can obtain high power factor and high performance.

Circuit of High Frequency Charge Pump Power-factor- correction Technique with Soft-switching



Zhang Zhuzheng Xie Yunxiang Lu Zhuqiang

2003, 31(6):  46-50. 

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The charge pump concept for achieving power-factor-correction (PFC) and its unity power factor condition are analyzed. A kind of high frequency charge pump PFC circuit is proposed in this paper. The principle of the circuit and soft-switching are discussed. The simulation and experimental results show that unity power factor and low total harmonic distortion (THD) can be achieved for the use of the circuit in electronic ballast, which proves that the performance of high frequency charge pump power factor correction is optimal.

Diffusion Bonding of Titanium Alloy to Stainless Steel Web with a Nickel Interlayer



Li Xiaoqiang Li Yuanyuan Shao Ming

2003, 31(6):  51-55. 

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The diffusion bonding technology of titanium alloy TC4 to stainless steel 00Cr18Ni10 web with a thin nickel interlayer, the microstructure of the joints and their mechanical properties were investigated. Experimental results show that when the diffusion layer of the joint comprised of a single brittle layer of TiNi or a multi-layer of Ti2Ni/TiNi/TiNi3, the strength of the joint was relatively low. As for the 30 μm thick interlayer of Ni, the optimum bonding parameters were as follows: bonding temperature θ = 850 ℃, bonding pressure p = 10 MPa and bonding time t = 10 - 15 min. So the shear strength of the joint without obvious shape changing was up to 146 MPa, which is one time higher than that of direct diffusion bonding.

Simulation of a Neural Network-based Path Planning Algorithm for Mobile Robot



Chen Huazhi Xie Cunxi Zeng Dehuai

2003, 31(6):  56-59. 

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A path planning algorithm based on neural network for mobile robots is introduced. It makes full use of the data fusion and parallel process of the neural network to improve the calculation speed of the algorithm. The algorithm also solves the problems of global path planning and local path planning for mobile robots. Simulation results show that the algorithm ensures quick and viable optimization of the non-collision path and adapts to the dynamic environment well.

Design of FR System in SDH Network Management and Its Realization by DSP



Fang Shaoyuan Zhu Xiaobo

2003, 31(6):  60-63. 

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The application of failure restraint (FR) technology in synchronous digital hierarchy (SDH) , the design theory and realization process of FR system are discussed in this paper. One method to implement FR system by using a DSP series port DMA is presented and the key technology of the whole scheme is analyzed in detail. The experimental results prove the validity of this method and some methods to further improve the FR system are put forward.

An Automatic Paper Marking System Based on the Form of HTML/XML



Liu Jianing

2003, 31(6):  64-66. 

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The automatic marking of subjective questions in the current computer-aided examination practice is investigated in this paper. A new approach is proposed to convert examination questions into text files in the form of HIML/XML to be judged and marked by the examiner. The related eigenvalue system is worked out, thus expanding the judgment scope to a great extent. The design of the system structure and the implementation of the system are also presented in the paper.

Application of Population-based Incremental Learning Algorithm in Solving Code Covering Problem



Lin Daying Hao Zhifeng Shu Lei

2003, 31(6):  67-70,75. 

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In this paper the code covering problem and some of its computer search algorithms are introduced. Based on population-based incremental learning (PBIL) algorithm, a fast algorithm is presented with heuristic feasible operator (HFO) to solve some binary code covering problems. According to local minimum traps, several jump-out strategies are designed. Finally some new ideas are proposed for the algorithm improvement.

Characteristics of Chitosan Degradation by Papain



Huang Yongchun Li Lin Guo Siyuan

2003, 31(6):  71-75. 

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The effects of reaction temperature, pH, enzyme content, chitosan mass concentration and degree of deacetylation on the chitosan degradation by papain were studied. The relationship between the degree of deacetylation and the relative content of GlcNAc-GlcN glycosidic linkages of chitosan was found by computer simulation. The results showed that papain only degraded the GlcNAc-GlcN glycosidic linkages, and the suitable temperature and pH were 45 t and 4.5, respectively.

Activity of Spirulina Platensis Polysaccharides and Their Sulfated Ester for Scavenging Hydroxyl Radical



Zhang Hairong Guo Siyuan Li Lin

2003, 31(6):  76-79. 

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Different fractions S1 ,S2 and S3 of Spirulina platensis raw polysaccharides were got by fractionation with cetyltrimethylammonium bromide (CTMAB) and ethanol. The SL1 SL2 and SL3 of sulfated polysaccharides were synthesized by modification with sulfuryl chloride. Sulfuric group content was determined by means of BaCl2-glutin turbidimetry. Some strong characteristic absorption peaks of ester sulphate bonds were observed at 1 240 cm-1, 810 cm-1 and 620 cm-1 respectively by FTIR. Fenton reaction was used as a producing hydroxyl radical model and the capacities of different fractions of sulfated polysaccharides for scavenging OH were compared with those of the unsulfated. Results demonstrated that there was a great difference for the scavenging OH capacities due to the differences of fraction, composition, polarity and acidity of polysaccharides. The order of capacity for scavenging hydroxyl radical was as follows; S1 > S3 > S2. The capacities of sulfated fractions SL2 and SL3 for scavenging OH were much stronger than those of the unesterified Spirulina platensis polysaccharides S2 and S3.

Effects of Biotin on Cell Growth and Astaxanthm Accumulation of Phaffia Rhodozyma



Zhu Mingjun Liang Shizhong

2003, 31(6):  80-84. 

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The effects of biotin on cell growth and astaxanthin accumulation of Phaffia rhodozyma were investigated in flasks. The addition of biotin promoted cell growth but decreased the cell astaxanthin content. The highest specific growth rate of 0.110 h-1 was achieved at 10 μg/L biotin. The highest cell dry weight of 9. 95 g/L was achieved at 6 μg/L biotin, which increased by 32% compared with 7.53 g/L when there was no biotin. As for astaxanthin production, the highest yield of astaxanthin of 3 825 μg/L and productivity of 53 μg/(L · h) were reached at 2 μg/L biotin, which increased by 30% compared with 2 944 μg/L and 41 μg/(L · h) with the absence of biotin, while the highest astaxantnin content of 391μg/g was reached at 0 μg/L biotin. This method provides a simple and inexpensive means to increase astaxanthin production in industrial fermentations.

Manufacture of the DNA Field-effect Transistor Sensor



Liao Jingsong, Zhang Shiuhua, Liu Zhongming, et al

2003, 31(6):  85-87. 

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A DNA field-effect transistor was manufactured. Single-stranded DNA modified with biotin was fixed on the surface of the sensor, using avidin as the connector. The stability and selectivity of DNA field effect transistor was studied, and the response of different complementary DNA concentration was determined.

Hydrothermal Preparation of Magnesium Hydroxide Particles with High Purity and Small Size



Wu Huijun Xiang Lan Zhu Dongsheng

2003, 31(6):  88-90. 

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With the aim of utilization of rich magnesium resources in China, magnesium hydroxide particles with high purity and small size has been synthesized by hydrothermal method. Preparation experiments were conducted in the presence or absence of hydrothermal treatment. The products were characterized by means of modem instruments as scanning electron microscopy (SEM) and X-fluorescence analysis. The experimental results indicate that magnesium hydroxide particles with perfect morphology, larger size and higher purity were formed after hydrothermal treatment, which was favorable for the dispersion of magnesium hydroxide in composite materials. The present work provided a possible route for the efficient utilization of magnesium resources in sea water.

Solution to Displacement Sensitivity for Structural Optimization Using Reanalysis Methods



Chen Fengping

2003, 31(6):  91-93. 

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A new method for solving displacement sensitivity is presented in this paper. Based on the combined approximation, the first-order and the second-order sensitivities of the displacements are derived. The solution process is based on the single exact analysis results of an initial design and is suitable for different types of modifications of the design variables and structures.

Oscillation of Two Dimension Impulsive Time-delay Lurie Direct Control Systems



Luo Qi Deng Feiqi Bao Jundong

2003, 31(6):  94-96. 

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The oscillation property of two dimension impulsive time-delay direct control systems is studied. Examples of oscillation and nonscillation via linear feedback control are given.