Volume 14,Issue 5,1991 Table of Contents

1 THE TOOTH FORM DESIGN OF CLOCK AND WATCH GEAR HOB AND ITS SUBSTITUTING CIRCULAR ARC

Li Weagui Deng Xingyi

1991, 14(5):16-23.

[Abstract](626) [HTML](0) [PDF 334.40 K](1934)

Abstract:
本文根据齿轮啮合原理,用矢量计算方法推出了钟表齿轮滚刀齿形设计的计算公式;详细讨论了满足误差控制要求的滚刀齿形代用圆弧的确定方法;并给出了在苹果—Ⅱ计算机上算出的例子。

2 THE DECENTRALIZED LOAD FREGUENCY CONTROL FOR MULTI-AREA POWER SYSTEMS

Gao Feng Qin Yihong

1991, 14(5):36-41.

[Abstract](828) [HTML](0) [PDF 240.42 K](210)

Abstract:
A decoupled load-frequency control model of a multi-area interconnecting power system is presented and a practical and effective decentralized control method is developed, which needs only its own state information and the information measured in it. It can also improve the stability and dynamic characters of the system. The dynamic simulation of the numerical example of a three-area interconnecting system with this controller showes the dynamic characters are almost the same as the centralized full state feedback optimal control.

3 A STUDY OF THE CONSTITUTION OF 42CrMo STEEL AFTER ION NITRIDING-PRECIPITATION HARDENING

Zhao Yuqin Zhou Shangqi Hu Zhenji Ren Qin

1991, 14(5):48-53.

[Abstract](820) [HTML](0) [PDF 290.72 K](255)

Abstract:
研究了42CrMo钢离子氮化—沉淀强化的组织结构,结果表明,离子氮化层的组成为ε、r＇a_N、Fe_3C和少量Cr_2N、Mo_2N、CrMoN_x及a";经时效处理后,ε相和a_N相弥散析出Cr_2N、Mo_2N和a" 。325℃时效,CrMoN_x消失;500℃时效,Mo_2N大大减少。a"、Cr_2N和Mo_2N弥散共格析出,必将使氮化层强化。

4 A NEW HEAT-TREATMENT TECHNOLOGY FOR EXTENDING SERVICE-LIFE OF ALUMINIUM-EXTRUSION DIES

Wang Linyun Chao Denju

1991, 14(5):54-59.

[Abstract](439) [HTML](0) [PDF 336.54 K](210)

Abstract:
本又认为角裂是铝热挤压模失效的主要方式。对有角裂的3Cr2W8V热挤压模的组织,断裂韧性进行了分析和测定,发现K_(IC)值低是角裂失效的主要原因。提出了能够提高3Cr2W8V热挤压模的韧性和使用期的热处理新工艺:在1150～1250℃高温淬火和低于500℃中温回火。结果使该类模具的使用期提高了1～3倍。

5 LASER REMELTING OF THE NiCoCrAlY PROTECTIVE COATING

Zhang Yaping Zou ZhirongGe Yunlong Ma Yuhuang

1991, 14(5):60-63.

[Abstract](429) [HTML](0) [PDF 232.40 K](177)

Abstract:
NiCoCrAlY protective coating is remelted on the GH140 alloy surface by 2KWCO2 gas laser,the results of which show that,by controlling proper laser technological parameters, the constitution can be fined,the composition can be well distributed,and the coating compactness and adhesion can be obviously enhanced in the laser-remelting zone. Thus,corrosion resistance and thermal fatigue resistance is effectively improved,and the good plasticity of the original coating is remained.

6 THERMODYNAMIC ANALYSIS AND OPTIMIZATION OF CONVECTIVE HEAT TRANSFER THROUGH A HORIZONTAL ANNULUS

Li Yourong

1991, 14(5):64-68.

[Abstract](515) [HTML](0) [PDF 188.71 K](173)

Abstract:
A second law analysis is carried out on convective heat transfer through a horizontal annulus with constant heat flux. The entropy generation rate expression is obtained,and the influence of heat transfer across a finite temperature difference and fluid friction on the entropy generation rate is discussed. The optimum geometric parameters of a horfzontal annulus is found for which the entropy generated is minimum. The optimum fluid velocity which corresponds to the optimum geometric parameters is recommended.

7 RESERCH ON THE COLD START OF 200MW CHINESS-BUILT STEAM TURBINES

Chen Feng Wang Airen

1991, 14(5):69-73.

[Abstract](629) [HTML](0) [PDF 268.20 K](167)

Abstract:
In this paper, the temperature field, stress, critical crack size and expenditure rate of life of HP and IP rotors of 200MW Chinese-built steam turbines in eight typital patterns of cold start of Chongqing Power Plant was calculated by finite element method. Some problems in speed-up process have been discussed, and advanced that it is better to appraise start-up process by Fracture Mechanics Mechod in the period when the temperature of rotor is low. The discussion are useful for the start of steam turbines.

8 GEOLOGICAL EVOLUTION OF YUXI COALFIELD

Wang Changxian Gao Wentai

1991, 14(5):74-80.

[Abstract](600) [HTML](0) [PDF 384.07 K](174)

Abstract:
This paper discusses the geological evolutional history of the YuXi coalfield from middle Proterzoic to Cenozoic. The main conclusions are that the deposition, structural deformation and magmatic activities of the coalfield ,to a great extent,are controlled by the tectonic developments of the south marginal area of the North China massif and strikingly differ from those of the interior area of the North China massif.

9 AN APPROACH TO SHARE DISTRIBUTED RESOURCES IN A LOCAL AREA NETWORK

Liu Zhaoyu Liu Weining

1991, 14(5):81-87.

[Abstract](425) [HTML](0) [PDF 364.99 K](141)

Abstract:
An algorithm of sharing distributed resoumes in a local area network is proposed , which is based on Queuing theory and statistics of probability. It is proved by means of a emulative program that this algorithm is simple, feasible and applicable.

10 AN INTELLIGENT BACKTRACKING METHOD FOR SOLVING COMBINATORIAL PROBLEMS

Zhou Liuding

1991, 14(5):88-95.

[Abstract](836) [HTML](0) [PDF 397.93 K](201)

Abstract:
This paper proposes an intelligent method for solving a kind of intractable combinatorial problems, investigates and analyzes several important problems of this kind Theoretical and experimental results show that this method is better than the classical backtracking method.

11 COMPUTER ANIMATED DISPLAY AND ITS APPLICATION IN MODAL ANALYSIS

He Yulin Liu Jing

1991, 14(5):96-102.

[Abstract](575) [HTML](0) [PDF 328.31 K](981)

Abstract:
This paper expounds a method of realizing animated display of structure model by computer animation at the request of test model analysis. The following problem have been discussed. They are the construction of structural geometric model,data processing and interchanging, two dimensional graphical display of three dimensional structure and the generation of computer animation.

12 MECHANICS OF COATS FROM PAINTING AND PLATING AND DAMPING PROPERTIES IN CYLINDRICAL SHELLS WITH OUTER COATS

Zhang Peiyuan Zhao Baomin

1991, 14(5):103-108.

[Abstract](394) [HTML](0) [PDF 226.99 K](877)

Abstract:
A mechanical model of coats is proposed to approach general theory and method in analysing it,and damping properies,stresses in coats and stresses between coats and body in a cylindrical shell with outer coats are given too.

13 THE REIMPROVEMENT FOR IMPULSE OF G. I. TAYLOR THEORY OF PLASTIC DEFORMATION IN IMPACT OF CYL1NDICAL PROJECTILES

Liu Xiangchen Li Zeqiang

1991, 14(5):109-115.

[Abstract](456) [HTML](0) [PDF 250.71 K](1226)

Abstract:
In this paper the reimprovement for G. I. Taylor theory of plastic deformation in impact of cylindical projectiles is done. The impulse in the reimproved theory is G. I. Taylor' s 1/2, and 3/4 of G. I. Taylor' s improved theory. The analytical solution of the reimproved theory shows that it gives better agreement with exprimental results than those of the original Taylor' s theory and, the improved theory.

14 A FUZZY COMPREHENSIVE EVALUATION METHOD BASED ON STANDARD INDEXES

Gong Peikang Wang Caihua

1991, 14(5):116-122.

[Abstract](435) [HTML](0) [PDF 305.55 K](871)

Abstract:
A method of fuzzy comprehensive evaluation based on standard indexes is presented. This method regards all sorts of standard indexes of evaluation objects as basic evaluation standards. Its main setps are: (1 )obtain evaluation parameters(all kinds of parameters which decide main performances of evaluation objects)and set up evaluation parameter matrix; (2) determine satisfaction degrees of various parameters and set up satisfaction degree matrix; (3) determine the weight of various prarmeters and set up the weight set; (4) make comprehensive evaluation and obtain evaluation result. Its common program is worked out and the typical example is presented.

15 BOUNDEDNESS AND GLOBAL STABILITY FOR A CLASS OF VOLTERRA PREY-PREDATOR SYSTEMS

Chen Junping

1991, 14(5):123-127.

[Abstract](350) [HTML](0) [PDF 197.71 K](1165)

Abstract:
The boundedness for a class of Volterra prey-predator systems is proved and the conditions of the global stability for this class are given.which are formally different from the previous conditions obtained by the same author.

16 THE EXISTENCE THEOREMS FOR CRITICAL POINTS OF A CLASS OF FUNCTIONALS

Zhang Xinyou Zhu Jisheng

1991, 14(5):128-132.

[Abstract](755) [HTML](0) [PDF 189.77 K](845)

Abstract:
Based on the notion of approximation, kind of sequence index (or,for simplicity ,S-index)for a class of functional on an infinite dimensional real Hilbert space is defined,and its significance in the critical point theory is investigated. Hence the S-index as a new theoretical tool to deal with the critical point problems for a class of functionals on the infinite dimensional Hilbert space is introduced.

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