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   Science & Technology Review
2007, Vol.25, No. 0708
25 April 2007

Articles
Reviews

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论文

Science & Technology Review. 2007, 25 (0708): 1-1. ;  doi:
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Abstract ( 263 )
系统仿真研究专题

Development of Power Plant Simulation Technology

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Science & Technology Review. 2007, 25 (0708): 5-10. ;  doi:
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Abstract ( 471 )
This paper first summarizes the development and the state-of-the-art of the power plant simulation technology and training simulators in the world, with focus on the progress of China's power plant simulation technology, where the number of simulators ranks the first in the world. Then the modeling theory and the related development are discussed with respect to its importance in improving the simulation technology, and are followed up with some research results of power plant simulation technologies in China. The future directions of the power plant simulation in China are pointed out at the end.

An Improved Numerical Calculation Method of Fluid Network for Real Time Simulation of Fossil Power Plant

Science & Technology Review. 2007, 25 (0708): 11-14. ;  doi:
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Abstract ( 467 )
The simulation of fluid network involves issues of non-liner, large, sparse matrix and stiff equations, and perhaps is the most challenging task in the plant simulation. Based on characteristics of non-linear equations, an improved iteration method is put forward in this paper, with a good convergence property as compared with the original Newton-Raphson method. An efficient spare matrix algorithm is also used to guarantee the simulation process to have a real time nature. The method dealing with the "stiff" problem occurred in the zero flow path and isolated islands is discussed.

Research on Object-oriented Graphical Modeling System Based on DCOSE

Science & Technology Review. 2007, 25 (0708): 15-18. ;  doi:
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Abstract ( 446 )
Based on the DCOSE simulation support environment, an object-oriented graphic modeling software package is designed and developed, including a module database, a resource database, unique network algorithms, electrical network algorithms, control and logical algorithms, and a series of software of management tools. This graphic modeling solution is completely open and object-oriented, which can be easily used to pre-process the module, debug the program, create and broadcast documents, and inquire information automatically. It can be widely used in the development of OTS (Operator Training Simulators) for power, petroleum and chemical plants, and now it has been successfully used in the development of more than 50 OTS for power plants.

Science & Technology Review. 2007, 25 (0708): 18-18. ;  doi:
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Abstract ( 242 )
Articles

Characteristics of Trade-wind Inversion over the Gulf of Mexico Coastlands of the United States from Radiosonde Observation

Science & Technology Review. 2007, 25 (0708): 19-25. ;  doi:
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Abstract ( 432 )
The radiosonde observations of eight years (1998-2005), launched from 9 stations over the Gulf of Mexico coastlands of the U.S., are analyzed to investigate local characteristics of Trade-Wind Inversion (TWI). Throughout the whole 8 years, the averaged occurrence rates of the TWI vary from 30% to 40%, the averaged bottom heights of the TWI vary in a range of 2 000~ 2 200 m, the averaged thicknesses, temperature differences between the bottom and the top of the layer and intensities range from 250~300 m, 2.0~3.0 K and 0.8~1.0 K/100 m, respectively. The occurrence rates of the TWI are higher in winter and spring and almost zero in summer and fall. The monthly-averaged occurrence rates of the TWI in whole 8 years show an obvious annual variation pattern. The seasonal and annual variability of the TWI in the Gulf of Mexico coastlands stations are inconsistent with those in Hawaii islands, and these discrepancies can be explained by different mechanisms of the TWI in these two areas.

Fragment Spatial Distribution Model for Small Caliber Air-burst Grenade and Its Applications

Science & Technology Review. 2007, 25 (0708): 26-29. ;  doi:
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Abstract ( 439 )
This fragment spatial distribution model is based on the Shapiro formula, where the ground and the shell body coordinate systems are established. The straight-line trajectory equation for the fragment spatial distribution in the ground coordinate system is obtained. The calculation results indicate that this method is of good precision, efficient and easy to use, and may serve as a basis for the future research on power of destruction for air-burst grenades.

Study on Vertical High Speed Gearbox in HTGR Helium Gas Turbine System

Science & Technology Review. 2007, 25 (0708): 30-33. ;  doi:
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Abstract ( 459 )
In a High Temperature Gas-cooled Reactor (HTGR) system, the gearbox is installed between Helium turbine and dynamotor, to reduce the high speed of gas turbine to a normal speed required by dynamotor rotor. Single reduction cylindrical gearbox is used with a pair of gears for high speed and normal speed regulations, respectively. The scheme is simple in structure, easy for manufacture and with high reliability. The disadvantage of such a scheme is the heaviness, and with the input and output centers being at different positions. In the gearbox, high speed electric generator and high power transducer can be avoided, to reduce the investment, instead by using a lubricant box, which increases the risk of HTGR Helium gas turbine system.

Treatment of Laboratory Wastewater with Flocculating and Adsorbing of Activated Carbon

Science & Technology Review. 2007, 25 (0708): 34-39. ;  doi:
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Abstract ( 451 )
A two-stage coagulation and adsorption process with charcoal absorbent was used to process laboratory wastewater, where heavy metal, sulfide, volatile phenols, aniline and degree of turbidity were analyzed. The results show that the two-stage coagulation by using copperas and PAC as flocculants to treat the wastewater can effectively reduce the content of heavy metal and sulfide. When PAC was used as the flocculant at the second stage of coagulation, the clearance of Cr6+ was better than that at the first stage of coagulation, reaching up to 90%. Moreover, the charcoal absorbent wiped off the volatile pHenols, sulfide and silver best, with clearance being 98%, 70% and 95.4%, respectively. All of the pollutants' concentrations can meet the national standard, and the turbidity of the sewage and the chroma are improved effectively. With the temperature, stir, aeration and pH in an adjusted range, the clearance of all contaminations can reach a value above 90%. Therefore the method of two-stage coagulation and adsorption of activated carbon is effective in processing laboratory wastewater, removing poisonous and deleterious matter from wastewater, and reducing the harm of the laboratory wastewater to the environment, with rapidity, low-cost and easiness.

Study on Eco-geographical Regions of Shanxi

Science & Technology Review. 2007, 25 (0708): 40-43. ;  doi:
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Abstract ( 459 )
The eco-geographical system is a hierarchical regional system divided or combined based on geographic-related comparison and integrated analysis of biological and non-biological factors on the earth's surface according to natural distributing laws. Related researches can serve as the basis for working out government strategies. Shanxi Province is situated at the middle reaches of Yellow River, the eastern part of loess plateau, on the west side of the North China great plains, and the special climate and soil conditions have created unique ecological problems for Shanxi Province. This paper uses cluster analysis of SPSS 10.0 on the basis of the traditional eco-geographical regionalization designated classification system, with the non-significant contribution indexes being removed. According to variations of natural conditions, the eco-geographical system of Shanxi province is divided into 6 eco-geographical regions, and the zoning plans are made by using DeltaGraph 5.0. The region's ecological problems and the ecological strategies of each region are briefly described.
Reviews

Progresses of Research on JC Virus and Applications in Studies on Origin of Mankind

Science & Technology Review. 2007, 25 (0708): 44-46. ;  doi:
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Abstract ( 434 )
The human polyomavirus JC virus, is ubiquitous in the human population and harmless for majority of individuals, infecting children asymptomatically. The JC virus is the etiologic agent of the fatal demyelinating disease Progressive Multifocal Leukoence phalopathy (PML) in immunocompromised individuals. However, there is no information available regarding the route of transmission, mainly because no obvious symptom is correlated with JC virus infection. The transmission of JC virus is considered virtually vertically from parents to children within the family. Thus the genotype identified as nucleartide polymophis of JC virus can be used as markers of ancient groups, which offers a novel means of tracing human migrations.
研究报告

Analysis on Inter-regional Industrial Links in the Exploitation of Coal

Science & Technology Review. 2007, 25 (0708): 47-53. ;  doi:
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Abstract ( 405 )
The industrial chain is important not only to the industrial development itself, but also to the regional economic development. To extend the industrial chain across regions, the concept of the inter-regional industrial link is put forward firstly, and then from the regional economical angle, the coal industrial chain in China and identifies existing problems are analysed. Finally, the importance of the inter-regional industrial link with special reference to the coal exploitation is discussed.

Study on the Client Credit Grading System for Rural Credit Cooperatives in China

Science & Technology Review. 2007, 25 (0708): 54-60. ;  doi:
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Abstract ( 395 )
Client credit grading system is an internal ratings-based system which banks use in order to regulate the credit business and reduce loan risks. It gives an objective and fair appreciation of a client's loan-repaying liability and credibility. Default probability is the main factors to be considered. The selected indicators should be scientific and reasonable, which will influence the usefulness of this system. Though rural credit cooperatives face the same credit risk as commercial banks, the current credit rating methods can not be adopted directly because their clients are different and the selected indicators may not be totally adequate. This paper uses factor analysis, cluster analysis, multi-variable discrete choice model, logistic model and practical data to test the client credit grading system proposed. The result shows that the system is applicable, but should be further improved.

Empirical Analysis of Relationship Between Real Estate Price and GDP in China

Science & Technology Review. 2007, 25 (0708): 61-64. ;  doi:
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Abstract ( 477 )
In recent years, the swift growth of China's real estate prices has drawn a wide attention. However, the studies on the factors influencing real estate prices in China are mainly qualitative in nature, with few quantitative and empirical analyses. In this paper, an empirical analysis of relationship between real estate prices and Gross Domestic Product (GDP) is made based on China's time-series statistics from 1987 to 2004 and with methods of co-integration test, Error Correction Model (ECM), Granger causality test. Empirical evidences show that there exists a long-term and steady dynamic equilibrium relationship between China's real estate prices and GDP. From both long-term and short-term points of view, China's GDP is the Granger cause for the variations of real estate prices. The trend of GDP has a decisive effect on both the increase and decrease of real estate prices. Therefore, the data of the fluctuation of GDP can be very useful in predicting the trend of real estate prices. Overheated economy during a short period will lead to a rapid increase of real estate prices.
科学家之声

Discussion on Some Crucial Issues Related to Soils and Fertilizers in China

Science & Technology Review. 2007, 25 (0708): 65-70. ;  doi:
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Abstract ( 1269 )
The paper discusses some crucial issues related to soils and fertilizers in China including resources and utilization of arable lands, soil fertility evolutions, effects of fertilizers on crop yields, soil biological fertility, newly emerged fertilizers and so on, and puts forward some strategic proposals for developing newly emerged fertilizers, enhancing long-term soil fertility monitoring, building up soil biological fertility and the safe use of organic manure.
学术争鸣

To Charge Publication Fee for the Periodicals of Science and Technology is Legal and Practical

Science & Technology Review. 2007, 25 (0708): 71-73. ;  doi:
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Abstract ( 1134 )
Facing someone who have censured on the topic of charging publication fee for the periodicals of science and technology, the authors are of the opinion that this step is warranted, legal and practical, and provide some suggestions on how to establish a more standard practice.
科技动态

Advances in Microbial Ecology——Brief Introduction of 11th International Symposium on Microbial Ecology

Science & Technology Review. 2007, 25 (0708): 74-77. ;  doi:
Full text: HTML (1 KB)  PDF  (309 KB)  ( 318 )
Abstract ( 432 )
A brief introduction of the 11th International Symposium on Microbial Ecology and part of lecture abstracts were reviewed, which reflects advances in modern microbial ecology.

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