Water scarcity of the Shiyang River Basin becomes more and more severe in recent years, which has led to a rapid degradation of ecological environment and human civilization created for a long period of time in the Minqin Oasis at the down stream and has caused deep concerns of all circles of life. The paper focuses on the utilization of water resources of the Minqin Oasis in different periods, analysis of the methods of ecological environment rehabilitation and reasonable water utilization. It shows that the Minqin Oasis will be destroyed if there are no new rescuning measures, according to balance calculation of water demand and supply. The paper delivered three proposals for the sustainable development of the Oasis and adequate water recovery of the Qingtu Lake at the end of the Shiyang River.
The content of computer network security is discussed in this article Firstly, the concept, system and structure and model of computer network security are given. Then the main content and correlative researching aspect are included. In the end, the main product is introduced.
Fundamentals of the unified technology combining plastic forming and heat treatment of materials mainly consist of the metallurgical and mechanical interactions between stress, transformation and deformation, modeling as well as simulations of microstructural and property evolutions. In the present work, taking steel for example, the literatures on ferrite, pearlite, bainite and martensitic transformations under stresses are introduced. Kinetics models and computer simulation of microstructural evolution of ferrite and pearlite transformations under stresses in a 0.38C-Cr-Mo steel are suggested. A discussion is given on deficiency and the modification of Scheil's additivity hypothesis. Phase field theory and its application, as well as the perspective in further study of the unified technology are briefly presented.
By the end of the 20 century, Chinese agriculture entered a new development stage. China has put into practice strategic adjustment in agriculture and rural economy, and obtained notable achievement.The 16th Session of CCP pointed out that the development of modern agriculture is one of the important missions to build well-off society in an all round way. Modern agriculture is a new stage of development´ after primitive agriculture and traditional agriculture, with abundant content, vivid characters and four kinds main forms. Modern agriculture development will face new situation, new strategies and countermeasures should be adopted.
The satellite mobile network is a sky-based communication network whose basic physical architecture is satellite constellation, and it covers the global areas with the communication links between the satellites. The satellite mobile network gives great impetuses to social development, scientific and technical advancement and military normalization, and it gives enormous challenge to the researchers because of the mobile character of the sky-network, the unmeant disconnection of the communication, the complexity of the access, and the integration of the use. It is necessary to use the general concept design simulation to validate general requirement, general project, key technical guideline, and resourceful restrictive condition, and then to form a scientific feasibility report. This paper introduces the general concept of the satellite mobile network, and designs a platform that aims at the simulation of the sky-network, and gains the data of the general concept design simulation of the satellite mobile network with some examples.
Through numerical solution of the dimensionless integral equations of the turbulent buoyant plume in stably linearly thermally stratified environments, the transportation laws of the buoyant flux, momentum flux and other parameters in the axial direction as well as the neutral buoyant force height and the maximum plume height are obtained. Measurements on the different fire smoke plumes in the medium-scale and big-scale experimental rooms indicate that the actual values of the maximum plume heights are consistent with both the numerical calculation results and the empirical formula in the available literatures, thus this work validates the integral model and provides a good foundation for the smoke transport research and fire detection technology development in big space buildings.
Serious dysfunction of cell-mediated immune is the internal cause of AIDS infection, and the virus is the external cause. The external cause will work only by means of the dysfunction of cell-mediated immune. As all the conditions on which normal cell depends are created by the viscera (zang and fu) function, proper measures can be adopted to adjust the viscera function comprehensively, so the physical materials can be produced, then the essence and sprit emerged. Only with supporting from physical materials, essence and sprit, can the cell-mediated immune function be kept well to conquer and destroy the different kinds of virus, hence keeping physical and psychological well-being, strengthening the human immunity. So that the normal physiological activity can be maintained.
To solve the high-dam navigation issue of the world class Three Gorges Project (TGP) is one of the key technical issues of the TGP. Special requirements exist in the TGP double-lane five-step shiplock in terms of general layout of navigation structures, sedimentation hindering to navigation, hydraulics of the water-conveyance system, high and steep slope treatment, manufacture and technology of main metal structures and mechanical and electric equipment, which have been resolved step by step by scientific tests, verification and engineering practice.
This paper outlines a systematic procedure for the design of a solenoidal coil and presents the optimum design of 1 MJ HTS magnet which is designed with Bi-2223 tape. At last the authors analyse the main magnetic component which influences the maximum critical current and discuss energy density, stray field and superconductors needed in multiple solenoid magnet with different elements.
Environmental isotope 2H, 18O and 3H, temperature and electric conductivity had been used to analyze bypass abutment seepage flow of Xin'anjiang right dam. Environmental isotope data on the right dam indicate the existence of bypass seepage flow in rock. The seepage water from the drainage gallery boreholes is not only from mountain precipitation but also from reservoir water that leak bypassing the right abutment. The reason of uplift cell 3E1-1 increasing is the result of the leakage from the fault F0. There is no seepage from reservoir to the grouted gallery through fault F1 under No. 6 and No. 7 dam section. Given the tritium is about 19.54 TU, the leakage water of G7-4 borehole comes from local precipitation of right dam. Part of reservoir water is proved to exist in the observation wells of right dam abutment. The data of environment also testified the result from the artificial tracer method.
Fire design is a key step in performance-based design. In this paper, several fire design methods have been introduced and fire design in a high-rack warehouse has been presented as an example to show how to apply fire design methods.
The key step of exploiting new type BMG is to judge quickly the glass forming ability (GFA) of bulk metallic glasses (BMG). The reliability and limitation that Trg was suited for judging of the GFA of BMG was made clear by using dynamics based on the addition principle in this paper, and the theory basis was provided for making BMG. The minimum of Trg for forming the BMG was 0.4066, at the same time, two theory optimum Trg, i.e. Trg = 1, Trg = 0, were obtained. A new parameter (CPS) for judging the magnitude or the smooth and stability of GFA of BMG was put forward, the magnitude of GFA of BMG was calculated by using it. The result of sequence of GFA of BMG was unanimous to Inoue's. At one time, the results were examined according to the average variance of Zmax and Rc of BMG, and all results were measured with one another. The magnitude of AHmg was a feasible method for quickly appraising the capacity and stability of GFA of BMG.
Based on the reliability design theory and sensitivity analysis method, the reliability sensitivity of the familiar spring for vehicles is extensively discussed and a numerical method for reliability sensitivity design is presented. The variation regularities of reliability sensitivity are obtained and the effects of design parameters on reliability of the familiar spring for vehicles are studied. The method presented in this paper provides the theoretic basis for the reliability design of the vehicle familiar spring.
Through the analysis model of economic effect and the data of the Sichuan Province input-output from 1987 to 1997, the state of economic effect of telecom manufacturing for 10 years is ahalysed. At the same time, the contribution and effect of telecom manufacturing on Sichuan's national economy are quantitatively and synthetically evaluated. It is found that the effect of Sichuan's telecom manufacturing is changing greatly from former “propelling model” to “driving model”. It proves the necessity of the preferential development of telecom manufacturing, which provides good countermeasure for the development of national economy in Sichuan Province.
In this paper, GPS measurement technology, Encke method to solve satellite orbit perturbation and generalized Kalman filtering technology are organically combined together, and an innovative solution— carrier phase & pseudorange integrated dynamic orbit determination (CPPIDOD) for low earth orbit spacecraft on-board autonomous precise navigation and positioning using GPS is presented. Difficult problems of dynamically resolving of integer ambiguities and amendment of cycle slips in the application of GPS carrier phase have been solved. Based on all these, technique of carrier phase & pseudorange integrated dynamic differential relative navigation between two spacecrafts is brought forward. Results of numerical simulation analyses and semi-physical simulation tests show that the solutions presented in this paper are feasible. They can significantly improve the performance of GPS positioning, and their models, algorithms and software are practical for engineering use.
This Issue
Jan 2004, Volume 6 Issue 1