The main causes for water pollution in the Three Gorges Reservoir Area were discussed . The key to water pollution prevention in the Three Gorges Reservoir Ar ea is to control and abate the production and discharge of pollutants from sources . The basic way to prevent water pollution is to fulfill scientific development view and complete three strategic transformations . In the reservoir bay and reaches that has been polluted ( for example : water bloom) , the pollution treatment should include measures of source control , end treatment and ecological restoration .
According to the problems of lacking of systematic and regul ar research in the development of GIS , this paper analyzed the social background , technology background and subject background in which GIS was produced and developed and explored changes of GIS architecture and software development model caused by the development of computer communication Web technology . It considered that the idea of Open GIS and Com GIS , which were distributed , was more fit for both data service and functional service under Web( Grid) environment , and put forward that GIS was developing into Open GIS based on Web services and Grid services . It also discussed the basic architecture and characteristics of sharing geographic information and data interaction based on Web services . At last , it proposed that Grid services provided a new opportunity and a new technology way to share geographic information and solve problems together , and underlined that the core of Web services and Grid services was services that both related and differentiated to each other .
Controlled demolition of concrete is one of the important and difficult problems in construction of reconstruction projects and expansion projects of hydropower projects . Based on systematic analysis of technologic requirements of controlled demolition of concrete , advantages , application conditions and implementation key points are summarized . That' s the selection criterion system of construction methods for controlled demolition of concrete . And the system is applied in Danjiangkou Dam heighting project of median- line of South- to- North Water Transfer Project . The final implementation effect is satisfying . The selection criterion system of construction methods for controlled demolition of concrete and representative successful implementation cases in Danjiangkou Dam heighting project will be helpful for similar projects in the future.
As the basis of nuclear technology , radiation technology ( radiation generating techniques , radiation detecting techniques and radiation application techniques) has been widely utilized in many areas . Based on beam generating and radiation detecting techniques , beam analysis is the typical application of radiation technology in material science . However , the purpose of analysis is improvement , optimization and development ; the important application is to improve materials , to modify materials and to develop new materials . On the research of radiation effect , it' s beneficial for us to analyze materials and to improve it or to develop new materials ; it' s also helpful for us to choose what kind of beams to destroy it and to design new type of beam weapons . Advanced material is the substantial basis for advanced weapon development and national defense power enhancement . To deploy the application of radiation technology , demands advanced material research to boost the discipline development . We should focus on high- tech materials which are essential to national strategic development as well as to research into the main task related materials .
Stress distribution in the third subsidence belt is presented , with great amounts of data on hydraulic fracture orientation obtained from monitoring hydraulic fracturing , and the direction of the maximum principle stress is specified . The results indicate that the third subsidence belt extends over 1 500 km from north to south , and the direction of the maximum principle stress ranges from 55° NE to 75° NE , concentrated on 65° NE , showing a stable distribution of the direction of maximum stress . The monitoring data implies that the tectonic stress direction in third subsidence belt is the combined result of South Asia Plate and Philippine Plate .
By setting a sinusoidal pulsed flow generator and an air chamber at the head and midst of conduit respectively , and elaborately structuring conditions of water jet system , a strong hydraulic resonance can be induced and pressure amplitude at nozzle can be greatly promoted . The mathematical- physical model of the system is illuminated with characteristics finite difference equations of hydraulic transient and solved by variable time step method . The conditions of desirable resonance are searched by direct search algorithm of Matlab . The sinusoidal pulsed flow generator is composed of a constant discharge pump and a piston cylinder fluctuating sinusoidally in volume . The constant discharge is provided by an electric piston pump driven by cam mechanism , and the sinusoidal volume fluctuation of the cylinder is produced by motion of piston driven by cam or crankshaft mechanism .
Through long- time filtering experiment in water treatment plant, indepth filtration mechanism and characteristics of the long fiber efficient filter , which has been patented with national invention, was studied in this paper. The bed structure characteristics of perfect filtering layer was showed in characteristics of the pore structure, filtrate water concentration, deposit in each layer and loss of filtering pressure along the depth of filtering bed. It was found that deposit lapse with depth of filter bed until exhaustion. It presents research direction for development of filter technique.
The thermal- oxydative ageing properties of ZN-1 damping rubber materials were investigated by using accelerated ageing test , then the relations between different ageing temperatures and ageing time and mechanical properties and damping properties of ZN-1 damping rubber materials were obtained . The results showed that with increasing ageing temperature and time , the tensile strength of ZN-1 damping rubber materials firstly decreases to a certain value and then increases ; the tensile elongation of ZN-1 damping rubber materials decreased . Finally , the ageing mechanisms of ZN-1 damping rubber materials were deduced from some analyses of the relation between macroscopical properties and microstructure
A result was discovered by analyzing the stability of rectan gular sheet compressed by the pressure. When the sheet metal is supported by the elastic pressing forces putting on the upper and lower surfaces of sheet in stamping, the sheet stability can be improved and the wrinkling of the sheet metal formed in forming process can be reduced. Based on the result, a novel stamping die was developed. The die can be reconfigured quickly and can suppress the wrinkling of sheet.
Ordering models are essential for most corporations , which are used to arrange the industrial production by the marketing situation . In the most supply chain enterprises , production is organized according to its sale , the ordering model of enterprises is especially important . In the case of retail ordering in steel enterprises , system dynamics is used to analyze the model of retail ordering system , and simulation analysis is aimed at its realism , then the retail ordering tactic in steel enterprises is proposed .
2 882 samples were taken in Qinghai- Tibet railway cars, and 1 693 samples were taken out randomly, then the factors that may affect the ability of individual' s hypoxia- resistant were analyzed in statistics. This paper has done this work by nonparametric statistics and correlation analysis , and got the conclusion that five factors, which are mountain sickness one have suffered before, sex, smoking frequency, bodily form and age, influence individual' s hypoxia- resistant ability. The conclusion makes a good sense, as it can provide statistics foundation for continuous iatrical research, while giving directive suggestion to reduce passengers' mountain sickness, and providing warranty for the design and amelioration of oxygen supplying system in Qinghai- Tibet railway cars .
Estimation of activity duration is a basic problem for project scheduling. However, the uncertainty of activity duration originates from both probability and fuzziness in the real world. This paper develops a linear programming method with LR type fuzzy numbers, which aims to estimate activity duration and identify critical path, and applies the λ - cut to indicate the degree of optimism of a decision maker. Finally, an example is given to demonstrate the application and validity of the proposed method.
To analyze the time- hopping (TH) impulse radio Ultra- Wideband (UWB) transmission performance in the presence of multipath, a model for Bit Error Rate (BER) analysis of UWB systems with coherent demodulation in the presence of inter- symbol interference, intra- symbol multipath interference , and multiple access interference is proposed by studying the statistics of multipath channel models, which is defined by the IEEE 802.15.3a Task Group, and then through calculating the variance of intra- symbol interference, inter- symbol interference and multiuser interference, system BER formulation is obtained and verified in comparison with computer simulations. By analyzing the average multipath interval and comparing BERs with and without intra- symbol interference , the results show that intra- symbol interference should not be neglected. Finally, to satisfy BER requirement, in various channel environments, the maximum transmission data rate is analyzed by both considering and neglecting intra- symbol interference in single user system, and the maximum average transmission data rate is analyzed corresponding to different user numbers in multi- user system .
The data dimensionality reduction is the main method that can enhance the outliers mining efficiency based on higher- dimension data set. The research of detection of outliers based on manifold learning is proposed after analyzing the advantages and disadvantages of the classical outlier mining algorithm in the paper. Local Linear Embedding algorithm (LLE) is an effective technique for nonlinear dimensionality reduction in manifold learning. Compared with other dimensionality reduction algorithms, the advantage of the local Linear Embedding algorithm is that it only defines unique parameter, i. e. number of nearest neighbours. With the idea of Local Linear Embedding, the algorithm can select optimal parameter and regulate the distance among data set after data dimensionality reduction, so as to improve efficiency of detection of outliers. The algorithm determines weighted values by discretion formula of weighted outliers. Through these weighted values, the experts can identify the outliers easily. Simulation results illustrate that this algorithm is very efficient. Moreover, our method has the advantage of simple parameter estimation and low parameter sensitivity. Our method gives a new way for the solution of detection of outliers.
One strain of Bacillus SP. from the activated sludge is able to produce a stable and efficient bio- flocculation. The flocculation properties and application of this microbial flocculants in wastewater treatment are studied. The results show that the optimum flocculation can be reached in conditions as follows: above pH 7.0, the dosage of coagulation aid CaCl2 is 5.0 % , the flocculants dosage is 0.2 % , and the centrifugal condition of flocculants broth is 4 000 r/min min and last for 30 min. In the optimum flocculation condition the strain boasts obvious coagulation efficiency in wastewater treatment with produced bio- flocculation.
This paper regards that individual value view ; social culture, technological efficiency and environment are the key factors that affect engineers' ethical tendency. And it discusses how the four factors affect the ethical sele ction and moral tendency of engineers in history and logic.