Using the surface observational data from 681 stations in the mainland of China from 1954 to 2001, the space-time distribution character and classification standard of the dust storms in China were analyzed, and some observation facts of the dust storms were given. Based on the analysis of the occurrence and development mechanism of the dust storms, the technology of the qualitative and quantitative forecast of the dust storm was discussed. It pointed out that the development orientation of warning technology on the quantity of dust storm is to develop the integrated forecast model system containing the atmosphere movement, the physical process of wind erosion and the information of land surface. Meanwhile, it indicated that the conventional monitoring network could not comprehensively monitor the occurrence and development of the dust storms. The specialized dust storm monitoring network including the factor of land surface environment and the factor of atmospheric physics and chemistry should be established, which is the root of the better understanding of the dust storm characters and the development of warning technology on the quantity of dust storm.
Large population, limited land resources and environmental pollution are the main constraints for sustainable land use in China. It is an ambitious goal of the new millennium to monitor land use dynamically with remote sensing technology, enhance management of primary agricultural land, build gardening and ecologically sound agricultural conditions, and to achieve dynamic balance of total agricultural land areas in China.
The evolution of gear measurement technology in the past 100 years is fully reviewed, and 6 key issues related to gear metrology are listed. Emphases are laid on the development of gear measurement principles, the evolution of technical measures realizing them and the interpretation & utilization of measurement results. Meanwhile, the principle, configuration and features of present-day CNC Gear Measuring Center are introduced. A few of new phenomena in the field of gear measurement technology are remarked, and some research topics in the near future are proposed.
This paper analyzes the mechanism of fiber bending and elongation of integrated piercing process, and builds the mechanical model of steely needle, then discusses the increasing and decreasing relation between maximum bending stress, maximum shear stress and the resistance that acts on needlepoint and radius and length of needlepoint, then optimizes the form of needlepoint according to the result.
Genetic algorithms search for the optimal solution by continually improving the individual of the population. Because of the difficulty in convergence and solving of individual fitness, standard genetic algorithm (SGA) is not used widely. Based on the improvement of SGA, especially the improvement of the selection operator in SGA, a new genetic algorithm(AGA) is proposed to solve the problems about the optimal operation of reservoirs. A new coding method is presented which is based on the subscript sequence of reservoir capacity array other than the water level sequence. An engineering example illustrates that AGA is much more efficient than SGA, and also the new coding method predigests the course of genetic algorithm in the optimal operation of reservoirs.
A sort of continued fuzzy operators is given. Proceeded from applied point of view, relation between the triangle norm operators most in use and the continued fuzzy operators is analyzed. A new fuzzy synthetic evaluation criterion and method are given. The new fuzzy synthetic evaluation criterion and method have some important characteristics as follows： using directly untransformed data; avoiding loss of original information; avoiding increase in interference information; bing very easy to tell which result is better in different papers.
This paper expatiates the thoughts of data mining with embedded knowledge and the techniques status quo of data mining. Based on the thoughts and the grey system (GS) theory, it proposes the GS-based data mining method set (GDMS) for time sequence first. Then this paper introduces the idiographic arithmetic withGM(1,1) as an example. Last, it forecasts the total homes connecting with Internet in Shanghai in M02—2005 by the arithmetic.
To be convenient for machining, the conventional axe-shaped pieces were approximately designed. It is proved that the traditional transition in a GTEM Cell can not give a satisfactory transmission loss distribution. So this paper gives the exact continuous curve equation for the axe-shaped piece´s two sides for the first time.
The new strength-toughen mechanisms, such as super fine Martensitic laths, new strength phases, Laves phase and M2C carbide, precipitated coherence with Martensitic matrix and the VIM + VAR double vacuum melting with super pureness, super homogenization hotwork, controlled Martensite transformation heat treatment techniques have been investigated. By means of them a new type of low carbon stainless steel, 14Cr-12Co-5Mo-Me, with ultra-high strength, high plasticity and high toughness was obtained.
The engineering water-pressure blasting for economizing energy and environmental protection isa new blasting technique. In this paper, the theoretic analysis and simulation experiment of the technique have been introduced in respect of enhancing explosive energy utilization ratio and protecting environment. The emphasis lie in innovating surmount feature, key technique and outstanding technique and economy effect has been obtained from factual use.
The purpose of this paper was providing some experience and ready reference for people who could design a utile and abroad popular GPS vehicle monitoring system. The author demonstrated some problems existing in the vehicle monitoring system, such as digital map model errors lead to map matching errors; telecommunication system information lag results in vehicle real time position error and global position system multipath error affects vehicle position. The authors had provided some schemes for solving the problems,e. g. GIS/DR protocol for solving telecommunication system information lag, nerve cell for solving global position system multipath. Experiment showed that the solution schemes had eliminated the system errors. The solution schemes had been applied to some projects,and had acquired very good application effect.
Multi-frictional disks are employed to transmit the torque in speeding wet clutch, and the oil thickness within frictional disks could be adjusted for practical output speeding. As oil combined with a-hydrocarbon or polyester is getting widely used as lubricant and the speeding wet clutch works within hydrodynamic lubrication, mixture lubrication, boundary lubrication and contact situations, the authors have established the thermal analysis model for investigating the behavior of frictional disks in speeding wet clutch, which covers the power - law fluid model, Patir - Cheng average flow model, GT asperity contact model, oil film inertia and heat effects, mean energy equation, and heat conduction equation. The formulas in the model have been inferred in this paper. The numeral calculation and analysis for hydrodynamic lubrication and mixture lubrication have been executed.
The paper discusses the relationship between three forms of carbonate as H2C03, HC03- and CC32- and water pH value when the groundwater temperature and partial pressure of C02 vary so as to evaluate the reliability of water quality. It finds out that the demarcation point of pH that is called pHO when the quantity of HCO3- reaches maximum, is from 7.92 to 8.60 in water and from 8.28 to 8.57 in open groundwater system of carbonate rock when pressure of CO2 in groundwater varies from 1 to 105 Pa and the groundwater temperature varies from 0 to 30℃ . pHO will be lower and lower with groundwater temperature being higher and higher. The pHO in groundwatar of limestone is almost equal to that of dolomite limestone owing to the solubility of dolomite is very low to calcite. So features of carbonate equilibrium in carbonate rock depend on component of calcite.
Based on the analyzing of the carbon cycle under different ecosystem in Liupan mountain forest zone and the conception of carbon sink and source , the impacts of land use change on the carbon sink of ecosystem were assessed. It is found that the function of ecosystem carbon source or sink under different land uses includes carbon storage, input and output of ecosystem carbon pool, net change of carbon storage and stabilization of soil organic carbon (SOC). The ecosystem carbon storage under natural secondary forest or plantation ecosystem is higher than that under cropland or rangeland ecosystem . The storage of ecosystem carbon, SOC, active SOC pool, slow SOC, protected and unprotected fraction of SOC and labile fraction of SOC under secondary forest or plantation ecosystem are higher than those under cropland and rangeland ecosystem. Natural secondary forest ecosystem is strong carbon sink, while plantation ecosystem is weak carbon sink, and cropland or rangeland ecosystem is source. The measures of increasing ecosystem sink include increasing input of ecosystem carbon pool, decreasing output of ecosystem carbon pool and increasing stabilization of SOC in ecosystem.
In order to give a more refined notion of information that is conveyed by ambiguous expressions, this paper analyzes how ambiguity affects the knowledge of the dialog participants and, especially, what they know about each other after an ambiguous sentence has been uttered. Methods of processing ambiguity based on Kripke structures in a multi-agent system is presented. The information states of multi-agent system are represented as a Kripke structures. The agents communicate with each other by means of a tell function, whose application is constrained by an implementation of some of Grice´s maxims. The method can easily distinguish semantic ambiguity from perceived ambiguity in the information conveyed by ambiguous sentences, so it is of practical value for researching on multi-agent systems.
According to the fuzzy theory and practical experience, the authors propose a rules autoconditioning fuzzy controller, whose dynamic performance and stability are all prior to the conventional PID controller and the basic fuzzy controller. It is also shown that the controller has good disturbance rejection properties and insensitivity to plant parameter variations. Both simulation and engineering prove that it is feasible actually and convenient to put into practical control project.
The development of long afterglow phosphors is discussed in this paper. Property and application of the phosphors are introduced in detail. It is sure that new long afterglow phosphors is excellent compared with traditional phosphors ZnS. Prospects of long afterglow phosphors is studied in the same time.
NMR has been widely applied to well logging and formation evaluation since 1990's. NMR core analysis, NMR wireline logging, NMR logging while drilling,as well as down hole NMR laboratory have been developed and available to the industry, which provide unique information to fluids identification and Petrophysical analysis. The NMR information provides： 1,lithology-independent porosity; 2,clay bound water, capillary bound water, and free fluids; 3,permeability; 4,oil and gas in free fluids; 5,fluids NMR properties at down hole conditions, etc. The availability of the NMR information dramatically enhances the accuracy of well logging fluids evaluation and makes the reserve calculation, Producibility estimation and stimulation evaluation feasible and much reliable. In this paper, referred to author´s new publication, NMR logging principles are briefly introduced, applications case studies to porosity, permeability, and oil and water saturation are discussed in details.
This Issue
Sep 2003, Volume 5 Issue 9