Volume 24,Issue 4,2001 Table of Contents

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  • 1  Numerical Investigation of Nonlinear Dynamics of Cavitation Bubble Motion
    ZHANG Feng hua LIAO Zhen fang TANG Chuan lin
    2001, 24(4):1-4. DOI: 10.11835/j.issn.1000-582X.2001.04.002
    [Abstract](537) [HTML](0) [PDF 180.55 K](734)
    Abstract:
    The nonlinear dynamic equation of cavitation bubble radial motion has been investigated numerically after accounting for the liquid compressibility. It is shown that the bubble motion presents the intense feature of nonlinear dynamics and the period doubling bifurcation is one of the routes to chaos. The indetermination of the cavitation bubble motion is revealed.
    2  Token of Three-dimension Size of Grain in Microstructure of Twin-roll Thin Strip
    YANG Ming bo PENG Xiao dong PAN Fu sheng DING Pei dao
    2001, 24(4):5. DOI: 10.11835/j.issn.1000-582X.2001.04.003
    [Abstract](561) [HTML](0) [PDF 253.29 K](883)
    Abstract:
    The property and behavior of twin roll thin strip is greatly affected by three dimension size of columnar and equiaxed crystal grains in the solidification structure of thin strip The growth of crystal grain has three dimension feature during casting process of thin strip, So the token of three dimension size of crystal grain cannot be realized by tradtional token method. On the basis of assumption to crystal grain shape, the token expression of three dimension size of columnar is established along with crystal grain in microstructure of twin roll thin strip according to quantitative metallurgical analysis and probability theory, And quantitative discription about three dimension growth feature of crystal grain in microstructure of twin roll thin strip is realized.
    3  Design Process Simulation Based On Information Dependency
    XU Xiao gang LIU Wei CHEN Ya Hua WEI Yun long
    2001, 24(4):8-11. DOI: 10.11835/j.issn.1000-582X.2001.04.004
    [Abstract](369) [HTML](0) [PDF 272.28 K](1061)
    Abstract:
    A modeling method based on DSM is introduced. In circumstance of iterative task, the ways concerning about the input of data,the generation of stochastic variables and the set of the simulation clock are dipicted. While considering the learning curve of activities, the way is studied express the movable process of a single project and then list the corresponding Monte Carlo simulative block diagram .The program based of EXCEL VBA is also written. The result of a given simulative example shows that the method can simulate complex design activities and plan the project in terms of scientific basis.
    4  Porous Hyperelastic Model for Foam Silicone Rubber
    LIU Zhan fang LI Ling feng HU Wen jun JIANG Rong feng
    2001, 24(4):12-16. DOI: 10.11835/j.issn.1000-582X.2001.04.005
    [Abstract](762) [HTML](0) [PDF 198.72 K](1038)
    Abstract:
    Foam silicone rubber is a typical porous material whose constitutive behaviors are attributed to the hyperelastic properties.A porous media model is introduced for a description of foam silicone rubber. In view of the hyperelastic constitutive features and the induced compressibility of material due to porous structural characters, the influences of porosity on deformation behaviors are investigated and the isochoric part and volumetric part of strain energy density function is built up. Uniaxial compression experiment demonstrats that the obtained constitutive relations works well to describe the mechanical properties under large deformation of foam silicone rubber.
    5  ZOOM FFT Technology Based on Analytic Signal and Band Pass Filter
    GUO Yu TAN Bao ping JI Yao bo QIN Shu ren
    2001, 24(4):17. DOI: 10.11835/j.issn.1000-582X.2001.04.006
    [Abstract](591) [HTML](0) [PDF 412.30 K](1082)
    Abstract:
    This paper deals on the method of ZOOM FFT based on analytic signal and band pass filter, which is different from other methods of ZOOM FFT. It is used on computer with larger zoom ratio; higher compute speed and so on than other ways for offline testing. It provides a new method for the development of Virtual Instruments on ZOOM FFT analysis.
    6  Study on Adaptive Sampling and Mesh Generation of Free-form Surfaces Based on Coordinate Measuring Machine
    CHEN Lang QIN Da tong XIE Yong
    2001, 24(4):22-25. DOI: 10.11835/j.issn.1000-582X.2001.04.007
    [Abstract](571) [HTML](0) [PDF 280.01 K](1169)
    Abstract:
    Digitizing of free form surfaces is one of key technologies on the reconstruction of free form surfaces. It is important to know how to sample properly free form surfaces on CMM, which concerns the reconstruction accuracy of free form surfaces and measuring efficiency. The mathematical model of sampling algorithm is proposed based on the concept of the center of gravity. Using the method, the topological information of surfaces can be preserved, and sampling mesh can be self organized. By analyzing and dealing with mesh data received from sampling algorithm, one approach with brevity and higher efficiency is provided on CMM.
    7  Repression of the Interference in the Wigner Distribution and the Algorithm
    JI Yue bo QIN Shu ren TANG Bao ping
    2001, 24(4):26-30. DOI: 10.11835/j.issn.1000-582X.2001.04.008
    [Abstract](534) [HTML](0) [PDF 367.23 K](802)
    Abstract:
    Although as being a real means of time frequency analysis, Wigner Distribution is limited by its falsity time frequency spectrum called interference item.By appliing the analytic signal and the Choi Williams Distribution to repress the interference and the time frequency spectrum got is satisfactory.The algorithm to compute the Wigner Distribution and the Choi Williams Distribution of the signal using its analytic form are fresented. Testifies The algorithm through several simulation tests using some typical signals such as segmented multicomponent signal, frequency modulation signal etc. The result is consistent with the theory. It indicates that the algorithm of the software developed is accurate.
    8  Development a Coil Compactor used in High Temperature
    FENG Guo liang
    2001, 24(4):31-33. DOI: 10.11835/j.issn.1000-582X.2001.04.009
    [Abstract](481) [HTML](0) [PDF 258.67 K](102)
    Abstract:
    The study of developing packing machinery used for coil compactor in high temperature is a meaningful subject , also a very difficult problem for the improvement automation level of steel rolling works . From 1970's to 1980's, several iron and steel works home tried their best to devolop the equipment, but no one succeeded . From 1991 to 1994 , a subject group of the author's joining had carried out the investigation and made the equipment 's model system. After trial and error, the model system has been used in factory test and the better results have been achieved . The packing machinery system's constitution ,control principle, characteristic and its application are introduced.
    9  Study on the Numerical Manifold Method Remeshing Technique and Its Application in metal Forming Processes
    LUO Shao ming CAI Yong chang ZHANG Xiang wei
    2001, 24(4):34. DOI: 10.11835/j.issn.1000-582X.2001.04.010
    [Abstract](748) [HTML](0) [PDF 299.21 K](144)
    Abstract:
    The criterion for remeshing and the automatic generating method of new mesh system are studied. The parameter transmitting method for the information transferring between new and old meshes is put forward by using Sherpard shape function. A general remeshing method suitable for two dimensional rigid plastic analysis is derived. The numerical examples show that the method is of high presicion and efficiency.
    10  Intelligent Initiative Security Vehicle System
    CAI Yi HUANG Xi yue ZHOU Xin WANG Xian ju HUANG Han ming
    2001, 24(4):38-41. DOI: 10.11835/j.issn.1000-582X.2001.04.011
    [Abstract](610) [HTML](0) [PDF 301.16 K](359)
    Abstract:
    Auto driving and safe driving constitute a control system which has multiple variables and features of uncertainers and delay response. Anautomobile and its suroundings are considered as a whole and an auto-suroundings feature model is presented based on knowledge expressing method which describles the status appear in the driving process. The constitution of auto driving auxiliary operation expert system is discussed. The computer simulation results show that the proposed knowledge expressing method and sysytem constitution method are effective and feasible .
    11  Research of Diagnosis of Disease Based on Character
    TU Yun hua HUANG Xi yue LI Jia WAN Yong
    2001, 24(4):42-44. DOI: 10.11835/j.issn.1000-582X.2001.04.012
    [Abstract](608) [HTML](0) [PDF 246.27 K](240)
    Abstract:
    On the basis of the character description of symptom of vegetable diseases and insect pests, by using methods and technology of knowledge engineering, with the help of the technology of Neural network, uncertainty reasoning, Multi media, friendly human computer interface, and cooperative conflicts resolution, the diagnose expert system framework for vegetable diseases and insect pests is implemented. The gradually learning and removing redundant samples with Rough sets theory is used in this Neural Network. The neural network was trained with the fact provided by the field expert in order to input symptom of vegetable diseases and insect pests visually.The way of inputting is choosing method. Prompting templets or object demonstration is lined out by the selecting button to help users to input conveniently. Using this framework, the diagnose Expert System of tomato diseases and insect pests was worked out.
    12  Fault Diagnosis Expert System of Combustion Engine with Rough Set Theory
    CAO Chang xiu SUN Ying kai CAO Long han ZHANG Bang li
    2001, 24(4):45. DOI: 10.11835/j.issn.1000-582X.2001.04.013
    [Abstract](574) [HTML](0) [PDF 253.35 K](77)
    Abstract:
    On the basis of fault diagnosis expert system, the rough set theory is introduced. Knowledge representation system table is taken as a major tool to reduce the rules of expert system in which unnecessary properties are eliminated. The redundancy of fault diagnosis information is revealed. The complexity of fault diagnosis expert system's structure is also reduced. The decision making rules are given finally.
    13  Building Enviornmental Monitoring System With COM
    WANG Ji feng PENG Dong bin
    2001, 24(4):48-50. DOI: 10.11835/j.issn.1000-582X.2001.04.014
    [Abstract](564) [HTML](0) [PDF 201.71 K](130)
    Abstract:
    This article presents an implement of component using COM technology for collecting environmental monitoring data in environment monitoring system. The component makes the separation of data collection and data analysis available.Simultaneously by using the interface of connectable object in COM,itmakes the cooperation of the environment monitoring software with other parts of fault management software available,and also the seamless connection.It improves the system's performance by adding extensibility and potential cooperatibility.
    14  A Statistical Model for Multi-paths Distribution under Mobile Environment
    LIN Jin zhao YU Ping Yang Shi zhong
    2001, 24(4):51-54. DOI: 10.11835/j.issn.1000-582X.2001.04.015
    [Abstract](499) [HTML](0) [PDF 239.43 K](95)
    Abstract:
    This paper presents the distribution function of multi paths by use of two stochastic processes. The first process which is a Poisson process presents the paths occurring, and the second one which is an exponential process presents the paths standing. If the maximal paths are infinite, the Poisson distribution can be concluded. The notable error exists between the Poisson model and the measurement result. So the Poisson model is modified depending on the fact that the arrival rate decreases and the standing time get longer with the increase of arrived paths. The numeric results verify the consistence between the modified model and measurement.
    15  Solution of the Eddy Current Distribution inside a Conductor Cylindrical Boundary Surface for Quasi-steady-state
    HU Wen jiang HU Xian quan
    2001, 24(4):55. DOI: 10.11835/j.issn.1000-582X.2001.04.016
    [Abstract](677) [HTML](0) [PDF 225.96 K](197)
    Abstract:
    通过求解麦克斯韦方程组,获得似稳条件下下导体圆柱面内的涡电流分布的严格数学解,并获得低频和高频情况下涡电流,涡旋电磁场的近似解,进而求出了趋肤效应的穿透深度δ。
    16  Design Approach to the Total Automation Systems of City Light Rail Transit
    MENG Jian bo ZHANG Jun LIU Shao yun XIANG Xiao bo
    2001, 24(4):58-60. DOI: 10.11835/j.issn.1000-582X.2001.04.017
    [Abstract](659) [HTML](0) [PDF 223.08 K](247)
    Abstract:
    The design approach to the total automation systems of city light rail transit (LRT) is discussed, according to the specialty of city transport systems. Based on the operation modes and basic functions of LRT, the scheme of automation systems by using of the networked PLC systems is introduced. The general analysis for each sub automation systems is given, and the redundancy and fault tolerant function are emphasized.
    17  Application of Wavelet Transform and HMM Model in Recognition of Speech Signals
    LI Jiao jun
    2001, 24(4):61-63. DOI: 10.11835/j.issn.1000-582X.2001.04.018
    [Abstract](890) [HTML](0) [PDF 189.52 K](142)
    Abstract:
    Some parameters based on wavelet transform and ARMA Model are presented. Wavelet transform provides a high frequency resolution, and the ARMA model is more powerful due to its including of the zeros pole in the model. The experimental result of alphabet of A to N from National Institute of Standard Technology (NIST) database is given. The error rate has been improved, especially C.
    18  Ice Jet and Ice Preparation
    ZHANG Dong su LIU Ben li LIU Li hong
    2001, 24(4):64-66. DOI: 10.11835/j.issn.1000-582X.2001.04.019
    [Abstract](576) [HTML](0) [PDF 113.94 K](1031)
    Abstract:
    An injection ice jet system has been studied and established.Through ice jet removing paint experiment,three parameters that influence removing efficiency such as flow,temperature,diameter are investigated.The experiment results come to the conclusion that ice jet can achieve removing paint in lower working pressure.Also a plan of preparing ice particles continuously has been put forward,and the analyses and calculations are done in terms of theory.
    19  Spontaneous Combustion Mechanism.of Gangue in Jingang Coal Mine
    HUANG Wen zhang QIU Xian de WANG Jian zhong ZHAO Chao ji
    2001, 24(4):67-70. DOI: 10.11835/j.issn.1000-582X.2001.04.020
    [Abstract](510) [HTML](0) [PDF 280.66 K](1110)
    Abstract:
    The temperature rise rate in oxidation process of gangue and coal specimen from Jingang Coal Mine has been investigated and the sulphur configuration in various kinds of gangue has been quantitatively analyzed to explore their spontaneous combustion mechanism. It is proved that the content of FeS 2 is very high in gangue of Jingang coal mine. A great deal of heat is released with the oxidation of FeS 2 in pyrites, the accumulation of heat results in gangue spontaneous combustion when the temperature reaches a certain degree.
    20  Mix Domain Decomposition Method with Boundary Element Method For Stokes Equations and Application
    YUAN Zheng qiang TAN Hong ZHU Jia lin
    2001, 24(4):71-73. DOI: 10.11835/j.issn.1000-582X.2001.04.021
    [Abstract](656) [HTML](0) [PDF 209.18 K](913)
    Abstract:
    As the BEM was used in the knaggy domain,its approach error was big.Domain Decomposition Method change the problem in the knaggy domain to the problem in several convex domains which do not wrap.The whole solution is gained by alternating boundary conditions between Dirichlet condition and Neumann condition on the common boundary.Domain Decomposition Method for Stokes equations in the anomalistic knaggy domain is presented,the example of Domain Decomposition Method in the flow of the lake in GuiYang City is given.
    21  Damage Analysis on Coal and Rocks and the Method of the Checking Damage by the Deviator Stress
    CAO Shu gang XIAN Xue fu
    2001, 24(4):74. DOI: 10.11835/j.issn.1000-582X.2001.04.022
    [Abstract](606) [HTML](0) [PDF 392.39 K](911)
    Abstract:
    The characteristic of the original damage and the breaking of the coal and rocks under the loading has been discussed by a lot of microscopic structure analysis and by whole stress strain testing on the coal and rocks. The non homogeneity causes the stress locating in a small spot. It is the essential cause of the damage developing and causing the structure breaking of the coal rocks. The failure of brittle fracturing, rubbing later on and granulating should be a major pattern in the outburst of coal and gas. The method of the examining damage by the deviator stress, is proposed. It can be used to analyse the characteristic of the coal and rocks.
    22  Model for Coupled Electro-Mechanical Behavior of Ferroelectric Crystal
    HE Yan song FAN Jing hong
    2001, 24(4):78-80. DOI: 10.11835/j.issn.1000-582X.2001.04.023
    [Abstract](720) [HTML](0) [PDF 216.62 K](1264)
    Abstract:
    Ferroelectrics are important materials applied in smart structure and system. A model is developed to simulate the electro-mechanical behavior of ferroelectric crystal. An analogy is drawn between the slip system of dislocation in metals and domain wall movement in ferroelectrics. It's assumed that switching is resisted by the dissipation motion of domain walls. Simulation results show typical nonlinear electro-mechanical behavior of ferroelectric crystal.
    23  Hyperelastic Constitutive Relations and Finite Element Formulation for Porous Silicone Rubber
    LI Ling feng LIU Zhan fang JIAN Kai lin HU Wen jun
    2001, 24(4):81-85. DOI: 10.11835/j.issn.1000-582X.2001.04.024
    [Abstract](677) [HTML](0) [PDF 311.62 K](1466)
    Abstract:
    The strain energy density function which was decoupled into isochoric parts and volumetric parts is presented for describing mechanical behaviors of compressible porous silicone rubber material,the constitutive model is then attained.The finite element formulation for isotropic hyperelastic porous silicone rubber is developed by use of total Lagrangean method.
    24  The Quantitative Analysis of the Fatalness of the Methane Explosion in Coal Mines
    LIU Li ping LIN Deng fa HE Chao yuan
    2001, 24(4):86-90. DOI: 10.11835/j.issn.1000-582X.2001.04.025
    [Abstract](714) [HTML](0) [PDF 325.71 K](1312)
    Abstract:
    If the quantitative index of the methane explosion in coal mines before exploding can be calculated, the measure will be take to prevent the methane explosion. The methods using in the analysis of the fatalness of the methane explosion are almost qualitative analysis. In this paper the quantitative analysis of the fatalness of the methane explosion in coal mines is achieved on the basis of the research of the essence event probability with the method of fault tree analysis using the micro-computer. The practical example of the quantitative analysis of the fatalness of the methane explosion in coal mines is given.
    25  Numerical Analysis on the Viscoelastic Characteristic of Cancellous Bone
    LI De yuan CHEN Hai bin
    2001, 24(4):91-94. DOI: 10.11835/j.issn.1000-582X.2001.04.026
    [Abstract](527) [HTML](0) [PDF 305.14 K](1150)
    Abstract:
    A one dimensional creep and stress relaxation response of cancellous bone to instant loading is investigated based on the studies with scanning microscope, can cancellous bone be viewed as a cellar solid consisting of an interconnected skeleton filled with medulla. A two phase poroelastic model is introduced to describe the cancellous bone, in which the tissue(material) densities of the skeleton and medulla are assumed to be unchangeable while the corresponding apparent densities are changeable due to the change of volume fraction. The governing equations are derived for the case of a linear poroelastic solid skeleton saturated with an inviscid medulla. Under the loading, responses of the skeleton stress as well as the medullary pressure are obtained with Laplace transform technique. The computational result shows that the cancellous bone is provided with certain features similar to those appearing in viscoelastic solids, which means the responses do not only depend on time, but furthermore depend on previous loading history. It is worth paying attention to the result that the medullary pressure can be negative. This point is due to the recovery of the skeleton after unloading whereas the medulla is not squeezed out but absorbed into the pores by suction.
    26  Filtering Method for the Decomposition of Heart Rate Variability Power Spectral
    ZHOU Jiang YANG Hao
    2001, 24(4):95-97110. DOI: 10.11835/j.issn.1000-582X.2001.04.027
    [Abstract](701) [HTML](0) [PDF 242.27 K](934)
    Abstract:
    Heart rate variability is a convenient tool to study the autonomic nervous system of human body. It is a focus of studying cardiovascular disease in clinic. The main spectral components are distinguished in the heart rate variability spectrum: ultra low frequency(ULF),very low frequency(VLF), low frequency(LF), high frequency(HF) components .While different part has different physiological meaning. This paper discusses the design of an effective digital filter for heart rate variability power spectral analysis,which provides a scientific measure of heart rate variability power spectral analysis in further studies and clinical applications.
    27  A Modern Spectrum Analysis Method for Pulse Abnormalities of Drug Abusers
    CHEN Ming jie CAI Kun bao SHI Yong zhi WANG Yong dong
    2001, 24(4):98-101. DOI: 10.11835/j.issn.1000-582X.2001.04.028
    [Abstract](691) [HTML](0) [PDF 264.15 K](950)
    Abstract:
    The pulse sense of PVDF is used to collection pulse signals of subjects into computer and store them in data file style. The author select a series of pulse signals randomly which contains 40 consecutive cardiac cycles of subject and using a modern spectrum analysis method to estimate the power spectrum of data in every cardiac cycle.An average power spectrum is obtained through averaging such 40 power spectra. It is found that the significant difference of power distribution exists between the heroin addicts and the healthy person. The frequency axis of average power spectrum. Calculating the power distributions on specified frequency bands of the average power spectrum for every subject is carved up.A primary criterion is obtained. The above criterion is applied to 30 subjects including 15 heroin addicts and 15 healthy persons. The correctness of classifying heroin addicts and healthy persons arrives 93.3%.The result shows that the modern spectrum analysis method is really an effective measure to analyze pulse abnormalities of heroin addicts.
    28  Nitration Process and Technology Research on MnN
    JIANG Han xiang LIU Ting jun DAI Qing xia
    2001, 24(4):102-105. DOI: 10.11835/j.issn.1000-582X.2001.04.029
    [Abstract](569) [HTML](0) [PDF 277.82 K](161)
    Abstract:
    介绍了利用金属锰粉采用固态氮化法生产氮化锰的原理和工艺。采用正交设计法,在实验室管式炉内、高温条件下利用氨气分解产生的活性氮对锰粉进行氮化获得氮化锰粉,通过一系列实验得出了适宜的技术工艺参数;锰粉粒度、氮化温度和氮化时间。获得了含氮高达6.880%-6.902%的氮化锰产品.
    29  Study on the Dearsenization of Hot Metal Using CaO Basis Fluxes
    LIU Shou ping SUN Shan chang ZHANG Bing huai WENG Guang yuan
    2001, 24(4):106-110. DOI: 10.11835/j.issn.1000-582X.2001.04.030
    [Abstract](518) [HTML](0) [PDF 337.88 K](169)
    Abstract:
    There is plenty of iron ore with arsenic in China. Because a proven dearsenization technique does not come into existence in now iron making and steel making processes and it is necessary for developing the dearsenization of hot metal technologics. A serial of dearsenization experiments are carried out on electric resistance heated furnace, it's found that arsenic in hot metal can be removed by CaO basis fluxes. X ray qualitative analysis of CaO basis slag after dearsenization revealed that the product of hot metal dearsenization with CaO slag is Ca 3As 2 and the dearsenization reaction is a reducing one. The thermodynamic conditions of dearsenization of hot metal using CaO basis fluxes are that the lower of oxygen fraction pressure of the system and [s] in hot metal, the higher of temperature of the system and basically of the slag, the dearsenization efficiency is better.
    30  Operation Circle Diagram of Ultra-high Voltage Long distance Transmission Line with the Constant Power Factor of Its End
    CHENG Tao LIN Li LONG Qi yu MOU Dao huai
    2001, 24(4):111-113. DOI: 10.11835/j.issn.1000-582X.2001.04.031
    [Abstract](566) [HTML](0) [PDF 188.30 K](177)
    Abstract:
    末端恒功率因数运行是超高压长线典型运行状态之一,由于解析式较为复,难于从中看出运行特征。文中提出用圆图分析这种状态下的运行特性。介绍了圆图的制定方法,并用圆图分析了超高压长线末端的功率-电压特性,计算出极限传输点参数,应用表明,该方法直观、清晰。
    31  RAPD Molecular Markers and Its Applications in Life Science
    LIU Yan OUYANG Ke qing ZHAO Hu cheng LI Xin ping CAI Shao xi
    2001, 24(4):114-117. DOI: 10.11835/j.issn.1000-582X.2001.04.032
    [Abstract](547) [HTML](0) [PDF 353.23 K](130)
    Abstract:
    A DNA polymorphison assay, random amplified polymorphic DNA (RAPD), was developed in 1990 based on amplification by the polymerase chain reaction (PCR) of random DNA segments and single primers of arbitrary uncleotide sequnce. The major advantage of this assay, contrasting with the restriction fragment length polymorphism (RFLP), is that there is no requirement for any specific sequence information on the target genome, as well as rapidity and simplicity.It has been widespread applied in life science researches such as the creation of high density genetic mapping, molecular phylogenetic study and gene location.
    32  Flow Boiling Heat Transfer of R134a in a Helical Coiled Tube
    CUI Wen zhi LIAO Quan XIN Ming dao
    2001, 24(4):118-121. DOI: 10.11835/j.issn.1000-582X.2001.04.033
    [Abstract](678) [HTML](0) [PDF 320.89 K](148)
    Abstract:
    制冷剂R134a作为CFCs类工质的替代物已经投入商业应用,螺旋管具有传热效率高、结构紧凑等优点,在各种工业领域中被广泛使用,研究R134a在螺旋管内的流动沸腾传热性能对制冷系统中新型蒸发器的设计具有重要意义。实验测量了R134a在管内径10mm,螺旋直径180mm,螺纹节距50mm的紫铜螺旋管内的流动沸腾传热系数。实验段外缠电阻丝加热,热流密度q=3-21.2kW/m^2,质量流量G=150-420kg/(m^2.s)。实验表明,由于二次流的存在,螺旋管对流动沸腾传热具有一定的强化作用,而且在低干度区的强化效果比高干度区更好。
    33  Research of Stocks Inherent Value and Growth of Listed Company
    ZHOU Zhuo hua ZHANG Zhong yi
    2001, 24(4):122-124. DOI: 10.11835/j.issn.1000-582X.2001.04.034
    [Abstract](405) [HTML](0) [PDF 223.39 K](114)
    Abstract:
    Appraise the Traditional stocks inherent value models ,and point out their shortcomings.Then a improved stocks inherent value model which emphasize growth of listed Company is set up.The improved model can explain the situation for the times of knowledge economy.Finally, the growth of listed company and is studied a analytic Hierarchy Process model to appraise the growth of listed company is set up.
    34  Conjugate Natural Convective Heat Transfer in an Enclosure with Discrete Protruded Heat Sources
    LI Long jian SONG Chang hua
    2001, 24(4):125-128. DOI: 10.11835/j.issn.1000-582X.2001.04.035
    [Abstract](619) [HTML](0) [PDF 320.48 K](189)
    Abstract:
    The mathematic model on natural convection is proposed in a two-dimensional enclosure cavity with an isothermal heat sink at one vertical wall and five discrete protruded sources. Numerical study is performed to analyze the natural convection in the enclosure with a variety of aspect ratio, the range of which is from 3.0 to 12.22, Ra H is 10 7 and Pr is 30.The computed results show that the total heat transfer effect under the situation with discrete protruded heat sources is prior to that with flat wall heated. Moreover, when the aspect ratio is comparatively large, there is several secondary flow in the enclosure, which enhance the convective heat transfer. On the contrary, when the aspect ratio is small, the secondary flow weakened or disappeared, and the total convective heat transfer drop. Finally, the convective heat transfer criteria in the enclosure is obtained.
    35  Social & Technique Security Problems In E-commerce
    YU Yuan hua
    2001, 24(4):129-132. DOI: 10.11835/j.issn.1000-582X.2001.04.036
    [Abstract](545) [HTML](0) [PDF 304.94 K](175)
    Abstract:
    The author analyzes the security problem in Internet and E commerce in the process of E commerce in detail.The necessary security in E commerce is introduced and setting up E commerce network and the social security circumstance is brought forward.It makes a cognizance study of electron evident, quickens the course of lawmaking in E commerce and limits the net station and its runner by laws, which can ensure the E commerce develop in a healthy way.
    36  Magnetoresistive Effect of Diamond Films
    KONG Chun yang WANG Wan lu LIAO Ke jun MA Yong WANG Shu xia FANG Liang
    2001, 24(4):133-136. DOI: 10.11835/j.issn.1000-582X.2001.04.037
    [Abstract](561) [HTML](0) [PDF 252.67 K](148)
    Abstract:
    On the basis of F S thin theory and taking the scattering of lattice vibration and impurities into account, the conductivity and the magnetoresistance of p type semiconducting diamond films (strip sample) are derived in spherical energy band and parallel connection model for light hold band,heavy hole band and split off band of diamond by solving the Boltzmann equation in the relaxation time approximation,. The relations between the magnetoresistance and thickness of diamond films,magnetic field strength and mobility are given. The magnetoresistance is influenced differently by light hole band,heavy-hole band and split off band. The deviation of the magnetoresistance is small between thick diamond films and lump. Magnetoresistive effects relate closely with temperature,magnetic filed strength and mobility.
    37  Spectrophotometric Determination of Trace Amont of Cadmium in Polyaluminium Chloride
    ZHENG Huai li ZHAO Hui ming LI Fang WEN Hua yong LI He ping
    2001, 24(4):137-139144. DOI: 10.11835/j.issn.1000-582X.2001.04.038
    [Abstract](661) [HTML](0) [PDF 235.61 K](127)
    Abstract:
    研究了聚合氯化铝絮凝剂中痕量镉的测定新方法并探讨了显色反应机理。新方法是利用分光光度法测定聚合氯化铝中痕量镉。它是在聚乙烯醇 (PVA)存在下 ,镉和碘化钾及罗丹明B进行显色反应。显色反应灵敏度高 ,其最大吸收波长为 6 0 6nm。表观摩尔吸光系数为 3 0 4× 10 5L·mol- 1·cm- 1。桑德尔灵敏度为 3 7× 10 - 4μgCd(Ⅱ ) /cm2 。镉含量在 0~ 0 6 μg/ 10ml范围内服从比尔定律。方法操作简便 ,不需要萃取分离 ,可在水相中直接测定 ,故大大简化了操作手续。将本法用于了聚合氯化铝絮凝剂中痕量镉测定 ,得满意结果。
    38  Applied Data Disposal Technology of Numerical Controlled Last Carving Machine
    WANG Xi LUO Da li SHI Dao yu QIAN Jia yu ZHONG Xian xin
    2001, 24(4):140-144. DOI: 10.11835/j.issn.1000-582X.2001.04.039
    [Abstract](698) [HTML](0) [PDF 180.17 K](877)
    Abstract:
    Necessary technical disposal methods of original last data before carving are introduced in turn.First,data interpolation and smoothness are adopted for removing absent dots and bug dots.Afterwards,all sections of last are rotated and central axis is adjusted because measurement axis and machining axis are not the same.Finally,head and tail of last are designed and appended in order to use clamp to fix last during the machining process.
    39  Approach on the Mechanism of Electron Field Emission from CVD Diamond Films
    WANG Bi ben WANG Wan lu LIAO Ke jun
    2001, 24(4):145-149. DOI: 10.11835/j.issn.1000-582X.2001.04.040
    [Abstract](590) [HTML](0) [PDF 341.35 K](1080)
    Abstract:
    The mechanism of electron field emission from CVD diamond films is investigated while analyzing its structure. The results indicate that there is some graphite in CVD diamond films and the coefficient which electrons tunneled through the diamond grains is enhanced because the electrons obtained energy from the electric field in graphite. Based on the results, a mechanism is put forward that enhancement of the electrons tunneled through diamond grains by graphite resulted in improvement electron emission from CVD diamond films. Some experimental results are well explained by the mechanism.
    40  Queueing System E / M/1
    孙荣恒
    2001, 24(4):150-153. DOI: 10.11835/j.issn.1000-582X.2001.04.041
    [Abstract](497) [HTML](0) [PDF 218.12 K](833)
    Abstract:
    研究排队系统E^ξk/M/1,给出该系统的队长,忙期、等待时间的分布以及其它一些结果。
    41  Multidimensional Multivariate Quantitative Structure- Activity Relationships of HMG-CoA Reductase Inhibitors
    王远强 白石Y 等
    2001, 24(4):154-158. DOI: 10.11835/j.issn.1000-582X.2001.04.042
    [Abstract](623) [HTML](0) [PDF 379.86 K](921)
    Abstract:
    采用比较分子场(CoMFA)分析法和偏最小二乘回归(PLS)法对十多种HMG-CoA还原酶阻滞剂的构效关系进行了多维定量建模研究,在描述变量数远远超过样本数的情况下,经典的Hansch方法等均不适应,而笔者的方法可给出良好结果。

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