Science & Technology Review CONTENTS

Vol.25  No.15  2007 (Sum No. 237)

This issue published on 10. Aug., 2007

Forward

1  The SI is facing great development

ZHANG Zhonghua

News Round

7   Exploring the Mysteries of the Unknown World

SU Qing

Special to S&T Review

15  Chinese Scientists and Engineers Full of Faith for the Future

Editorial Department

Articles

16  Relationship Between Frost Indexes and Viticulture Zoning in China in Recent 45 Years

LI Hua, WANG Hua, YOU Jie, et al

23  Influence of Light Polarization on Two-beam Coupling in Nematic Liquid Crystals

REN Changyu, JIN Yongjun, REN Dunliang, et al.

Abstract: An experimental investigation on diffraction of two different polarized incident lights in C60-doped Nematic Liquid Crystal (NLC) homeotropically aligned is reported. The experiment shows that much greater energy transfer is created in grating recorded by horizontal polarization (P-P polarization) beams than that by vertical polarization (S-S polarization) ones, and the energy transfer direction is totally opposite. It is shown that when one incident beam polarization state is changed, the intensity of diffraction and transmitted beam will be changed accordingly after the grating is written. The polarization state is a very important parameter in the determination of nonlinear reorientation NLC. Nonlinear phenomena caused by molecular reorientation and their dependence on light polarization should be very useful in potential applications for optoelectronic functional elements.

Key Words: nematic liquid crystal; orientational photorefractive effect; tow-beam coupling

CLC Number: O753+.2  Document Code: A  Article ID: 1000-7857(2007)15-0023-04

27  Design and Application of the Ω Type Junction Workpiece Without Slot

ZHU Wenqin,WANG Fengcai

Abstract: In view of the drawbacks of the existing highway bridge expansion joint, this paper proposes a kind of the Ω type spandrel elastic junction workpiece, with novel design and good performance. The structure and working principle of the joint are presented. The force, stress and deformation are analyzed under the circumstances with temperature variations. The calculation method of the junction workpiece without slot and its extended application are discussed.

Key Words: anisotropy; expand when hot and contract when cold; compensation; deformation; stress

CLC Number: U443.31  Document Code: A  Article ID: 1000-7857(2007)15-0027-04

31  Development of FCC Diesel Hydro-dearomatization Catalyst ARO-1

ZHU Jinling, WANG Fucun, TIAN Ran, et al.

Abstract: ARO-1 catalyst is a hydro-dearomatization catalyst newly developed by Daqing Chemical Research Center. Its evaluation was conducted on a 15 mL hydrogenation test unit with Daqing FCC diesel being used as feedstock. The evaluation results show that ARO-1 catalyst enjoys excellent HDA, HDS, HDN performance: desulfurization rate of 97.8%, denitrogenation ratio of 99.8％, density reduction of 0.041 6 g/cm3, diesel yield of 98.0 wt%, therefore, ARO-1 is a good FCC diesel hydro-dearomatization catalyst.

Key Words: FCC diesel fuel; hydro-dearomatization; catalyst

CLC Number: TE624.9+3  Document Code: A  Article ID: 1000-7857(2007)15-0031-04

35  Risk Analysis on Direct Property Damage for Major Fire Incidents in Towns Based on Association Rules

FU Zhimin, CHEN Yunguo

Abstract: Risk analysis on direct property damage for 1 356 major fire incidents in towns from 2000 to 2005 is carried out based on association rules analysis with respect to time, place and cause by SPSS Clementine 8.1 software. The results show that a fire may easily turn into a major fire incident with direct property damage, in cases of electric fire in workshop, storeroom fire in November, shop fire from 2:00 to 3:00, electric fire from 23:00 to 24:00, electric fire and fire from 18:00 to 19:00 in July, workshop fire due to electric failure in July and shop fire due to electric failure from 21:00 to 22:00. These results may serve as a guidance for taking more effective fire protection measures and improving the efficiency of combat readiness for fire fighting.

Key Words: major fire in town; direct property damage; association rules; data mining tool

CLC Number: X932  Document Code: A  Article ID: 1000-7857(2007)15-0035-05

40  Studies on Synthesis of 1,2-(methylenedioxy) benzene

LI Xin, ZHAO Shiju, WU Juan, et al.

Abstract: 1,2-(methylenedioxy)benzene is synthesized by using catechol, dichloromethane and dimethylsulfoxide with the condition of alkali and normal pressure. Overall yield of the process is 73.4%. Influence of material ratio, concentration, temperature and dosage of catalyst on the reaction is investigated and the optimum condition is obtained. Product is analyzed by infrared spectrum and gas chromatogram. Results show that the product is 1,2-(methylenedioxy)benzene and the content by gravity is 98.6%.

Key Words: 1,2-(methylenedioxy)benzene; catechol; technics

CLC Number: O621.256.9  Document Code: A  Article ID: 1000-7857(2007)15-0040-04

44  Design of Speech Compression System Based on AMBE-2000 of the Short-wave Communication

CHEN Hua, GUAN Yudong, SHI Zhenqiu

Abstract: The quality of communication can be improved by using the technology of digital signal processing for a system of short-wave communication. This paper proposes a design of speech compression system based on AMBE-2000, including hardware and software, and the interface between different parts of the system. At the end, based on the result of test, the key technologies in developing AMBE-2000 are summarized.

Key Words: AMBE-2000; shortwave; speech compression; speech coding

CLC Number: TN912  Document Code: A  Article ID: 1000-7857（2007）15-0044-04

48  Framework Study on Safety of Logistics System

CHEN Zhigang, CHEN XiangFeng, HUANG Zhongding

Abstract: The frequency of accidents is high in China's logistics industry and huge damages to the society and economy are involved. The government and enterprises' safety measures to protect the logistics system are often inadequate due to lack of a good understanding of logistics safety. Thus it is necessary to have a framework of logistics safety system including several important aspects. This paper proposes a framework for four logistics functions including storage, transportation, information and transaction, in three levels: technology, processing and personal management, as a basis for an effective logistics safety system. Three modules with respect to preventions, maintenances and emergencies are summarized. Some measures for logistics safety  are suggested based on the theory of securities chain.

Key Words: logistics; safety system; chain of security

ClC Number: F253.9   Document Code: A  Article ID: 1000-7857(2007)15-0048-05

53  A New Algorithm for Solving Plane Travelling Salesman Problem: Travelling-around-the-center Method

YU Deming

Abstract: A new algorithm, called the travelling-around-the-center method, is proposed in this paper. It is a deterministic algorithm,  with its time complexity the same as  the  nearest neighbor  algorithm, that is,  O(n2),  where n is  the number of cities. Numerical tests for plane travelling salesman problems with various sizes are carried out by using the travelling-around-the-center method and the nearest neighbor algorithm, and the performances of both algorithms are compared. The following conclusions are drawn: (1) The relative performances of the solutions of the travelling-around-the-center method and the nearest neighbor algorithm depend on the number and distribution of the cities in a specific travelling salesman problem. (2) For n=4, the travelling-around-the-center method can always obtain the best solution, while the nearest neighbor algorithm often cannot do so. (3) For a small size problem with n<20, the travelling-around-the-center method can generally obtain better solutions than the nearest neighbor algorithm. (4) For a middle size problem with 20≤n≤30, the quality of the solution obtained by the travelling-around-the-center method is similar to that obtained by the nearest neighbor algorithm. (5) For a large size problem with n>30, the quality of the solution obtained by the travelling-around-the-center method is generally not as good as that obtained by the nearest neighbor algorithm.

Key Words: plane travelling salesman problem; travelling-around-the-center method; numerical tests; nearest neighbor algorithm; comparison analysis

ClC Number:  TP301  Document Code: A  Article ID: 1000-7857(2007)15-0053-05

58  Application of Neural Network Based on Fuzzy Clustering in the Classification Algorithm of Data Mining

WANG Gang, HUANG Lihua, ZHANG Chenghong

Abstract: The common classification algorithms, such as Decision Tree, Bayesian classification and Artificial Neural Network, provide an important foundation for the classification algorithm of data mining. But due to huge amounts of data, these algorithms face some challenges in time efficiency, robustness and accuracy. This paper proposes an artificial neural network model based on fuzzy clustering. First, it clusters the training data into different sub-data using the Fuzzy Clustering Model. Subsequently, it uses various artificial neural networks to train the sub-data. After that, the number and complexity of training data is reduced and the efficiency of the artificial neural network is enhanced greatly. In the end, the UCI's databases are used to prove the usefulness of the new classification algorithm. The results show the validity of application of the Neural Network based on fuzzy clustering in the classification of data mining.

Key Words: data Mining；classification；neural network；fuzzy clustering

CLC Number: TP18  Document Code: A  Article ID: 1000-7857(2007)15-0058-04

62  Comparison Between Chinese and American Non-governmental Science and Technology Awards

CHEN Haidong, KE Zineng，DIN Zhaojun

Abstract: The history and the present state of Chinese and American non-governmental science and technology awards are systematically studied in this paper. Through comparison and analysis, the authors find that there are similarities in four aspects and differences in five aspects in them. Some suggestions are made on promoting Chinese non-governmental science and technology awards.

Key Words: science and technology award; non-governmental organization; comparison between China and America

CLC Number: N01  Document Code: A  Article ID: 1000-7857(2007)15-0062-05

Reviews

67  Nano Cryosurgical Therapy: New Frontier in Nano Medicine

LIU Jing

75  Research and Product Development of Cordyceps militaris and Its Bioactive Substances

NI He, LI Haihang, HUANG Wenfang, et al.

80  Notes on Reviews in Chinese Science Abstracts (Chinese Edition)

Commentary

81  Emphasis Given to Complementary and Alternative Medicine in Developed Countries

FU Junying, WU Yishan

Science Reports

82  Effect of Traditional Culture on the Development of Science and Technology

84  The Math Problems Facing the New Century

Suggestion

85  Grasping the Opportunity to Develop High Field MR Imaging, etc.

Editor-in-chief's Thoughts

89  How to Pound the Foundation of Postgraduates Successful Research Career (VII)

FENG Changgen

Special Columns

6  Cover Story

8  Half-month News Briefs

10  International Journal Highlights

11  Domestic Journal Highlights

12  Scientific Community Briefs

14  Voice of Scientific Community

86  Book Appraisal

87  Events

88  Readers'Letters

90  Guidance for Contributors to Science and Technology Review

91  Entertainmen t

93  Digest of Chinese Newspapers and Journals

94  Career

96  Global Jobs