A brief introduction of the ideas, theories, hierarchical structure, methods, and systems of materials design initiated and promoted actively by famous scientist Qian Xuesen in recent 20 years is presented in this paper. After a sustained effort contributed by the “863” Program expert team, materials design has been scheduled into the nation´s general new material development plan and encouraging progress has been made.
Lightning is a natural phenomenon that seriously affects the natural environment and human activities. Therefore, it is of important social, economical and scientific value to detect the lightning effectively. Comparing with the developed countries, China has some gaps in the fields of lightning studying, forecasting and detecting. In this article, the mechanism of lightning and its influence are described. The present situation and the direction of lightning detecting technology at home and abroad are also analyzed. Several suggestions and issues have been proposed for constructing the national lightning detecting network.
The lube oil corporations in China should create name brand products, and form competition advantage through product serialization, product mix rationalization, mass production and scale marketing, and management modernization. They should realize interregional and international operation, build great scale with strength and rebuild strength with great scale, improve their overall quality to accept challenge. Based on particular analyses of lube oil marketing actuality in China and the future situation, the paper brings forward seven ideas for lube oil corporations development in China. They are： forming great scale management through reforming corporation and strong corporations unity; internationalization management through carrying out image strategy and forming brand advantage, increasing product competitiveness through adjusting product mix; creating core competition ability through increasing investment in science and technology; enhancing product quality credit through strengthening quality management; doing better technical services through reinforcing marketing net construction, and enhancing corporation competition ability through deepening management and modern technique.
Chinese Medicine (CM) becomes more and more attractive and welcome to the world, for its unique medical theory and certain therapeutic effect with few side effects. With China's entering WTO, it is very important to establish a standardized system for the production and research of Chinese Herbs (CH), push forward the modernization of CH and make CH accepted to the world.
The goals of the modernization of CH are： establishing perfect research and production systems, strengthening.
The research of CH, developing high quality, effective, stable and dependable new Chinese herbs, and improving the therapeutic effect of CH to ensure the health of the people, making CH go to the world.
The guarantee of the modernization of CH are： the integration of CM and CH, the integration of CM and modern medicine, and the integration of inheriting and innovating.
The main contents of the modernization of CH include： the modernization of the theory of CM, the modernization of GH resources and its generation, the modernization of medieal materials and Yin Pian, the modernization of preparation, the modernization of the pharmacological research of CH, the modernization of the toxicological research of CH, the modernization of the clinic research of CH, and the modernization of the CH enterprises.
The real-time forecast of irrigation is one of the essential part of the work for compiling a dynamic plan of irrigation water use. It plays an important role in saving water, increasing crop yields and economic benefits in an irrigation area. The real-time forecast of water requirements of crops is the essential and difficult part in the real-time foreast of irrigation. The methods and models for the conventional forecast of crop water requirement ,applied both in China and the world, are based on the application of the historic data from typical hydro-logic years. They can not used for the real-time forecast. In this paper, on the basis of the analyses of the relationship between the crop water requirements and the meteorological factors and non-meteorological factors such as the factors of plant and soil, the method and models for the real-time forecast of crop water requirements based on the factors of weather types, leaves cover percentage and effective soil moisture are presented and recommended. The concrete steps and computer block diagram are introduced. The main improvements are that the weather type is used instead of such four meteorological factors in Modified Peman's Eguation as air temperature, humidity, sunshine hour and wind speed,the leaves cover percentage is used instead of the leaves area index, and an improved equation for calculating soil moisture correction coefficient is proposed. Based on the results of the real-time forecast of crop water requirement and precipitation, the real-time measurement of soil moisture (for dry food crops fields) or depth of water layer (for paddy fields) and the maximum and minimum values of soil moisture content or water depth for getting high yields and saving water, and the calculation of field water balance, the method and models of real-time irrigation forecast including the real-time forecast of the date and quota of irrigation for both dry food crops fields and paddy fields are presented. In this paper, the precision of the real-time forecast and its effects on increasing yield and saving water are also introduced and discussed.
On the basis of paper ( I ) , this paper realized the reduction of the knowledge base and constructed the two coordinators and a component in the double-bases cooperating mechanism. Furthermore, the KDD* , which is the combination of KDD and double-bases cooperating mechanism, is constructed as an open and optimized enlargement of KDD. In the same time, this paper proposes a new association rule mining algorithm——Maradbcm which is based on the study on the inner mechanism, i. e. double base cooperating mechanism, of KDD and explains the algorithm of Maradbcm and Apriori respectively. Through the analysis of the algorithm and examples, it is shown that the main disadvantage of Apriori, overall database searching and deleting meaningful rules by minimum support threshold during creating large item set, can be overcome by Maradbcm algorithm. Then this paper proposed a new clustering method based on double-base cooperating mechanism. It is shown that the study of inner mechanism is important to the KDD mainstream development and it also provides a new path for the research in the area of knowledge discovery system.
As one of the most important issues in multiprocessor systems, data locality is a main direction of studies on such systems. Combining the recent research achievements by the authors with the current state of studies in this field, a systematic discussion on data locality and its optimization technologies in multiprocessor systems was brought forth. Driven by the deficiency of current locality measurement models, an enhanced model suitable for hierarchy parallel computer architectures was proposed. Besides, from the viewpoint of static locality optimization technologies, a data transformation framework based on projection and delaminating policy was designed. While on the side of dynamic locality optimization technologies, a dynamic page migration mechanism based on instantaneous access information was implemented. More discussion about both static and dynamic optimization policies was presented in this paper. In addition, in-depth investigation on memory consistency model ,which raised as a key problem in exploiting locality optimization, was also stressed and a new model centered on operating system——thread consistency model was put forward.
Nonlinear fracture behaviors of concrete materials are mainly caused by the cohesive stress along the fracture process zone. Based upon concrete fracture properties and the analytical model of crack with cohesive forces, two simple formulae concisely expressing the cohesive stress distribution are presented through analyzing characteristics of the cohesive force distribution function. One formula has only one undefined parameter. The other one has two undefined parameters. According to the superposition principle of deformation body, a formula for calculating the sole undefined parameter to control the cohesive force distribution function is deduced. Similarly, two algebra equations for solving the two undefined parameters also for controlling the cohesive force distribution are given. As a result, using the test data of crack opening displacement, the cohesive stress distribution is determined. The relevant calculation examples and discussions are given, too, in this paper.
When compartment fire reaches flashover, the temperature rises rapidly, resulting in the ignition of all surfaces of the combustibles within the compartment. In this paper, the suppression method of adding sand into the fire source (gasoline) is discussed. Through assuminga transition layer below the surface of sand, the combustion process of the fire source can be simplified. It is found that the time to the peak value of the upper layer temperature, the peak value itself and the rate of extinguishment have obvious dependence on the volume ratio of sand to the fire source (gasoline) . Experimental results show that the theoretical analy is reasonable.
In this paper, the traditional hydrostatic characteristic formulas of hydrostatic bearing, or slide guide, are analyzed. These formulas aren't used to calculate and design the parameters of hydrostatic bearings due to the innate defects. At the same time, new formulas for hydrostatic characteristic of bearing are presented .Using new formulas to design and calculate the parameters of hydrostatic bearing may got exact results quickly and efficiently, because the new formulas can reflect the nonlinear relation between the static load forced on the axle neck and the bearing clearance.
Given in this paper is successful experience in improvement of navigation channels in Pearl River, the largest river in South China. The reach to be improved is in the confluence zone of the West and the North Rivers. Various types of shoal exist in this waterway as a main stem for flood to progress. The flow condition is very complicated and improvement is very difficult. In this paper, based on a great deal of hydrological data and topographical data, analysis of hydro-dynamic conditions, water/sediment conditions and river bed evolution are pressented. In combination with scale modeling test, the mechanism for the shoals to grow is revealed and an improvement plan is drawn out according to the features of the waterway. According to the plan, in order to solve the deposition problem in Laoyazhou Shoal, groynes are built to move the flow diversion point and remove the circular flow on the shoal. The condition for deposition to occur is then destroyed and the shoal vanishes after improvement. The navigation channel becomes smooth. For the problems of “risk” and “shallow” at the west mouth of Sixianjiao Navigation Channel, low “lock-dams” are built in the branch to confine the hydrodynamics so as to get rid of the “risk”. At the same time, the flow overflows the dams and scours the bed materials so that the problem of “shallow” can be relaxed. After the improvement, the depth of the overall waterway increases from less than 2.0 m to larger than 2.5m. Ships over one thousand tons can then pass through the navigation channel and favorite conditions are then developed for flood disposal and drainage. Remarkable economic and social benefits are got.
Techniques from the second moment method and reliability optimization design method are employed to present the practical and effective method for the reliability optimization design for coil tube-spring on the condition of known probabilistic characteristics of basic random variables. The respective program can be used to obtain the reliability optimization design information of coil tube-spring accurately and quickly.
An analysis method based on fractals and wavelet for machined surface profile error was presented. It can be employed to analyze the machined surface in details, and reconstruct the surface profile for doing some related work, such as performance-tolerance analysis and process quality control. The fractal dimension algorithms, the analysis and reconstruction algorithms of surface profile based on wavelets theories were developed. The given example showed that this method and related algorithms were very effective.
Transnational corporations carry out the global strategy, from product export, capital export to brand export. This kind of multipurpose export which relies on abundant capital and is guaranteed by the advanced technology, as a flag with brand ,impacts greatly the national brand and gives it a severe challenge. Facing the foreign brand large-scale entering, the problem appears gradually that national brands are short of competitiveness. The author tries to discuss countermeasures to improve brand competitiveness by analyzing the influencing factor of brand competitiveness.
The sum and difference patterns as well as the directivity of the monopulse antenna arrays are optimized based on genetic algorithms (GA). When only the sum pattern is optimized as usual, the difference pattern and gain can not be guaranteed, so the track precision and effective distance of the antenna or missile will be impaired. However, using GA, the sum pattern, difference pattern and directivity can be optimized thoroughly for the antenna design.
This paper summarizes the current research and applications of oil field chemical additives in drilling fluids, completion fluids, and reservoir protection, and holds the view that the research and applications of the positive ion drilling and completion fluid system should be the development orientation in the future. For the development trend of oilfield chemical additives, it is, guided by new oilfield chemistry theory, to design molecules, develop new-style monomers, synthesize new types of polymers, and develop modified products of multifunctional natural polymers with environmental-amity.
This Issue
May 2002, Volume 4 Issue 5