Volume 14,Issue 4,1991 Table of Contents

1 AN ENDOCHRONIC MODEL FOR NORMALLY CONSOLIDATED SOILS

1991, 14(4):1-7.

[Abstract](573) [HTML](0) [PDF 313.78 K](181)

Abstract:
本文对内时理论在土壤中应用的三个问题进行了研究。首先,用微观扰动弹性概念和合理定义内蕴时间,建立一种新的内时本构模型,用以描述剪缩土的基本力学特性;其次,探讨了内时本构模型的破坏和屈服问题,详细研究了破坏函数F(σ,θ)的数学表达式与土破坏准则的关系;最后,讨论了只用一条静水压缩曲线和一条常规三轴压缩曲线确定模型参数的方法与步骤,并用粘土试验资料检验了模型。

2 VARIABLE DAMP STRUCTURAL RELIABILITY DUE TO MULTIPLE RANDOM EXCITATIONS AND SENSETIVITY ANALYSIS

Zhang Xiangwei Xu Meihe

1991, 14(4):8-15.

[Abstract](483) [HTML](0) [PDF 266.37 K](174)

Abstract:
The reliability of random vibration is discussed,and then by using the first order perturbation method and with the aid of relation of the systemic response function to the first order sensetivity of variable damp parameter, the rate of change of structural reliability indication is derived, therefore the constraint equation to guarantee reliability for the structural optimization design is proved and the satisfactory result is obtained,test and the practicability of this method is tested.

3 A FINITE ELEMENT ALGORITHM FOR PARALLEL PROCESSING OF MULTI-FRONTS

Hu Ning Chang Ruqing

1991, 14(4):16-19.

[Abstract](763) [HTML](0) [PDF 225.11 K](175)

Abstract:
In this paper,a new algorithm for solving large-scale finite element system is presented, which utilizes the architecture of parallel processing. Firstly, the structure is partitioned into sub-regions. Then multi-fronts are used to assemble and eliminate concurrently in every sub-region. Thus the condensed interface stiffness matrices and load vectors are obtained. By serially assembling and solving global equation to get interface displacements and backing to every sub-region, the inter-nodal displacements and element stresses can be solved. The results of computation show that it can not only increase the speed of computation,but also save the memory space of computer effectively. This algorithm is an effective method for solving large-scale structural finite element systems.

4 A METHOD FOR CALCULATING STRESS INTENSITY FACTORS OF CHEVRON-NOTCHED THREE-POINT BEND ROUND BAR SPECIMENS

Wang Qizhi Xian Xuefu

1991, 14(4):20-24.

[Abstract](773) [HTML](0) [PDF 188.65 K](202)

Abstract:
An effective approximate method is proposed to obtain the stress intensity factors (SIF) of the chevron notched three-point bend round bar specimens, the least square principle is applied to fit the results into a polynomial for SIF,which is applied to the fracture toughness specimen suggested by the International Society for Rock Mechanics(ISRM) ,the result is satisfatory.

5 A STATIC STRESS ANALYSIS OF THE EFFECT OF STRATIFICATION PLANE OF ROCK MASSES ON SMOOTH BLASTING

Qian Yefu

1991, 14(4):25-28.

[Abstract](396) [HTML](0) [PDF 150.25 K](178)

Abstract:
The influenfial factors of stratification plane to smooth blasting are studied according to the ti eory of smooth blasting and the anslysis of static stress. The results show that the angle p between the maximum principal plane and the rertical line of stratification plane has some influence on the fracture of rock masses.

6 THE MEASUREMENT OF PLASTIC ZONE AT FATIGUE CRACK TIP BY FRINGE METHOD

Zhang JinYu Qi

1991, 14(4):29-33.

[Abstract](637) [HTML](0) [PDF 241.53 K](179)

Abstract:
本文用云纹法获得了GCr15钢经拉一拉疲劳试验后裂纹尖端的云纹信息,计算处理得出裂纹尖端塑性区的主应变场,其形状好似蝴蝶,建立了蝴蝶形主应变场的数学式子。实验结果表明:与轴呈45°方向上的ε_x为零且主应变场梯度最小,而沿裂纹方向主应变梯度最大,间接地证实了Laird的展性裂纹扩展钝化机制。

7 FORCED CONVECTION ON WALL-PROTRUDED HEAT BLOCK IN PARALLEL FLAT PLATES

Ding Xiaojiang Xin Mindao

1991, 14(4):34-39.

[Abstract](597) [HTML](0) [PDF 296.61 K](1327)

Abstract:
用数值计算法对平行平板通道内二维凸出块热源的强迫对流换热进行了研究。分析了通道中的流场和温度场变化,详细计算了热源各个表面的换热以及热源高度变化的影响,整理出各个表面平均换热以及整个热源总的平均换热关系式。雷诺数变化范围:100≤Re≤1500,热源相对高度变化:1/8≤h/H≤1/2。热源块总的平均换热关系式: Nu_m=1.0377Re~(0.37)·(h/H)~(-0.17)

8 A THEORETICAL ANALYSIS OF THE SPURIOUS SIDEBANDS AT THE OUTPUT OF A NEW PLL

Cao Rui Song Junshou Wu Yongxiang

1991, 14(4):40-45.

[Abstract](550) [HTML](0) [PDF 219.09 K](777)

Abstract:
Based on the introduction to a new type of PLL for digital frequency synthesis, this paper describes on detail the suppression of the specific spurious signals occurring at the output of the phase detector of the PLL. The result shows that the output sideband-to-carrier ratio is satisfactory.

9 A STUDY OF THE SENSITIVITY OF BIQUADRATIC SWITCHED CAPACITOR FILTER

Zeng Xiaoping

1991, 14(4):46-52.

[Abstract](606) [HTML](0) [PDF 246.56 K](1067)

Abstract:
分析了双二阶开关电容滤波器(SCF)特征角频率ω_0和品质因数Q的灵敏度,以高Q带通滤波器为例,计算了SC支路按不同方向转移的三种不同电路以及单位电容改变时的S_x~ω_0和S_x~Q,并给出了计算机仿真结果。结果表明,ω_0和Q的灵敏度可精确地用各支路电容解析表达,其值只取决于各支路电容比而与电容值无关,当支路增益转移时,其灵敏度相应转置。

10 AN ON-LINE ALGORITHM FOR PREDICTING THE TEMPERATURE OF POWER TRANSFORMER WINDINGS

Wen AnYe Yilin

1991, 14(4):53-59.

[Abstract](684) [HTML](0) [PDF 310.80 K](1424)

Abstract:
The paper presents an on-line algorithm for predicting the average temperature of power transformer winding according to its load current. The algorithm has accounted for the whole history of load current and variations of ambient temperature. The overload capabilities of transformer can be increased by monitoring and controlling the winding temperature and the necessary durability of the transformer can be ensured. The algorithm can also forecast the future winding temperature and the time of reaching the max, permitted the assumed future load current and oil temperature.

11 A STUDY OF THERMOTECHNICAL CHARACTERISTICS IN FORCED CONVECTION BATCH FURNACE

Wen Guanghua Gao jiarui

1991, 14(4):60-65.

[Abstract](407) [HTML](0) [PDF 285.69 K](970)

Abstract:
An experimental study of heat transfer mechanism and characteristics of high velocity circulation combustion gas in a batch heat treatment furnace with high velocity burner was presented. The regular patterns of variation of total heat flux, heat convection and radiation heat fluxes given heating materials with heating time were obtained. It was revealed from the results of experiment and calculation that inverse heat flux of metal radiation is an unavoidable heat transfer characteristic.

12 DYNAMIC ANALYSIS OF WET-BOTTOM BOILER WITH OPEN FURNACE

Ding Cuiqing Lu Xianyang

1991, 14(4):66-72.

[Abstract](429) [HTML](0) [PDF 316.45 K](838)

Abstract:
The dynamic caclucation and analysis for a wet-bottom boiler with open furnace is presented in accordance with its structual and thermal parameters.

13 SEVERAL THEORETICAL PROBLEMS OF VISCOELASTICITY MEASUREMENT OF BLOOD

Cai Shaoxi Wu Xi

1991, 14(4):73-77.

[Abstract](621) [HTML](0) [PDF 255.02 K](1049)

Abstract:
In order to tackle the present difficult problems in viscoelasticity measurement of blood and other biofluids with Couette and cone-plate rheometers, the effect of inertia of inner cylinder and sample on the measurement result is studied. Rheological models of the instruments are reconsidered. Based on theoretical analysis of the flow state of the non-Newtonian fluid,a corrected method for calculating Theological parameters of sample is proposed.

14 A QUICK THINNING AND SEGMENTATION ALGORITHM FOR HAND-PRINTED CHINESE CHARACTERS

Liu Ping

1991, 14(4):78-85.

[Abstract](709) [HTML](0) [PDF 316.44 K](1217)

Abstract:
The paper proposes a quick thinning and segmentation algorithm for hand-printed Chinese characters going on simultaneously. The memory space occupied by the character image data is only one four hundredth of that by the normal character matrix. Any hand-printed Chinese characer can be thinned and segmented into several simple lines,are and corner strokes. It is very efficient for structual feature extraction for Chinese characters. A new chain code for edge description is also proposed, whose average chain code length is about 20% less than that of Freeman chain code.

15 DIRECT METHOD OF PROBABILISTIC PRODUCTION SIMULATION BASED ON MIXTURES OF NORMAL DISTRIBUTIONS

Zhang Zongyi Yang Xiutai Xu GuoyuLiang Xinhua Pu Xinmuo Zhang Yuancai

1991, 14(4):86-92.

[Abstract](556) [HTML](0) [PDF 263.18 K](877)

Abstract:
This paper describes a new probabilistic production simulation method based on mixtures of normal distributions. This method does not require to modify the original load,and the relevant formulae are derived directly from the mixture of normal distributions of load and the mixture of normal distributions of system power. Numerical results indicate that this method is accurate and rapid in comparison with the conventional and the cumulant methods.

16 ELLIPSOMETRIC SPECTROSCOPY OF ELECTROCHROMISM OF POLYANILINE FILMS

Xie Shangfen Shen Hui

1991, 14(4):93-96.

[Abstract](625) [HTML](0) [PDF 188.52 K](818)

Abstract:
The electrochromism of polyaniline films, which is prepared by electropolymer-ization from aniline in acidic aqueous solution onto platinum,is investigated in 330-700nm through in-situ ellipsometric technique. The results indicate that the ellipsometric peak of the reduced state(-0. 2V) of the film appears at 390-400nm and the oxidized state(0. 55V) at 500-530nm. The elec-trochromic reaction from the reduced "yellow" state to the oxidized "green" state is suggested via intermediate state whose ellipsometric peak appears at 466-470nm.

17 THE UNCONDITIONAL STABILITY AND THE DELAY BOUND FOURTH-ORDER NEUTRAL DELAY DIFFERENTIAL EQUATION

Chen Junping Li Zhiyong

1991, 14(4):97-103.

[Abstract](326) [HTML](0) [PDF 249.30 K](196)

Abstract:
导出了四阶常系数中立型时滞方程(1)当θ≠1时为无条件稳定的充分条件,对θ≠1,α_3=α＇_3或θ=1两类方程导出了其为无条件稳定的充要条件。这些条件是简明而实用的代数判定条件,此外,给出了时滞界限。

18 A STUDY OF THE OPTIMIZATION OF CIRCULAR ARC TOOTH PROFILE TRANSMISSION

Yan Zhonghong Li Pingyuan

1991, 14(4):111-116.

[Abstract](408) [HTML](0) [PDF 251.25 K](190)

Abstract:
For the first time, we point out the new idea that we can approximate the involute tooth profile transmission to circular arc tooth profile transmission. Looking upon it as a fourbar linkage we try to minimax the error of the velocity ratio and evaluate the strong-weak point of circular arc tooth profile transmission.

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