The urban environmental security becomes a new hot spot of environmental problems at present. The environmental security is raised in correspondance with the environmental calamity. This article puts forwad urban environmental security and the preparatory scheme for heavy environmental disaster rescue for Beijing based on analysis of some insecurity environmental factors of Beijing. The research contents include: The Beijing urban environmental security; The environmental disaster comprehensive zoning in Beijing; The information system supporting the management and decision about environmental disaster;The rescue and prevention scheme of urban meterological disaster;The forest fire prevention of Beijing by GIS technology;The cause and prevention strategy of dust storm;The health security and epidemic prevention in Beijing;The study of earthquake disaster prevention; Transform, perfection and construction of urban lifeline system engineering; The rescue scheme for serious environmental disaster; The effect of environmental disaster on urban economic development in Beijing.
The deep water high earth-rock cofferdam in the 2nd phase construction of TGP is a hard and challenge project, whose degree of difficulty in the technological problems is much harder than that of the similar projects. During the period from 1998 to 2002, the cofferdam protected the construction pit of the left-bank dam and powerhouse, stood the test of the heavy flood in 1998, and made the 2nd stage construction completed smoothly. The quality of the cofferdam is good, and it fulfilled the historical tasks satisfactorily. The article introduced the whole course of the systematical research through the aspects of the experimental research, the design and construction, the organization and management, the safety monitor and the cofferdam demolition etc.
The structure, reproduction, replication and transcription of RNA viruses were introduced. Antivirus strategies including design of anti - SARS drugs, RNA interference, DNA vaccine delivery system, modulation of interaction of envelop glycoprotein with glycosanminoglycan derivatives or analogues, natural herbal medicine and alveolus tissue engineering were reviewed. These examples imply the interactions of RNA viruses with proteins, DNA, and polysaccharides. Nowadays biomaterials matrixes or vectors are developing toward the third generation, i.e. cell or/and activated ones. It is sure that biomaterials will play a crucial role in fighting against SARS viruses and the like.
Review of 10 years development of industrial fibers materials indicates that they are still in a continuous development. It is necessary study the development of the world and absorb beneficial experience. The paper prospects main applications and focuses on solving macro management problems.
The present situation of new energy resources at home and abroad is briefly introduced and the development prospect of various new energy resources is pointed out.
A new model has been developed for studying the mechanism of infiltration destruction by contact scouring between the hardpan and grid. The permeability of coarseness gap that formed by different lithology is substituted by the permeability of slippery cranny, and the permeability of the stratum can be expressed by a combination of the permeability of gap and sand and gravel. The starting speed of the fine sand can be used as differentiation criterion. To calculate the fine sand moving by stabilization flow theorem in different time part, the fine sand near the orifice flows out of the stratum at the beginning. At first the permeability coefficient near the orifice becomes larger, and then it developes inside. It will develope rapidly in the direction perpendicular to tho bank, and even forms a concentrate leakage passage.
This paper discusses non-optimum analysis theory of system and points out main problem of exploring indefinite system optimization. The key is short of the non-optimum analysis to the system. The article establishes symptom covey and empirical analysis based on non-optimum category of the system, and puts forward that system is degree measured along with non-optimum traced up to systematic self-organization and so on.
This paper investigates a decomposition formula of Walsh spectrum for a class of Boolean functions. On the basis of this formula, the constructions of some cryptographic functions, such as resilient functions, Bent functions and H-Boolean function are studied H-Boolean function is a class of Boolean functions of much importance to the applications of coding theory and satisfying the strict Avalanche criterion.
The project was designed according to the theory of biological fixation and removal of manganese. The process included weak aeration and one filtration. Inoculating the aboriginal manganese removal bacteria from raw water, after 2～3 months culture, the filter obtained the strong manganese removal ability. Under the condition of usual filtrating rate, manganese in treated water was 0.05 mg/L,and TFe was trace which were superior to the national standard although the manganese in raw water was 1～3 mg/L and TFe was 0.1～0.5 mg/L. The quality of the treated water was stable and met the industry requirement. This theory solved the difficulty of manganese removal over the past harf of century and built the fist biological removal of iron and manganese water plant in the world.
In order to confirm the dependence of the resistance of cavitation erosion and abrasion (CEA) on the common properties of materials, four typical materials (WC coating, NiCr alloy coating, boron stainless steel and titanium) were used to do the experiments of CEA and cavitation erosion (CE), to do corrosive experiment, and to test their hardnesses. The experiments results indicated that all resistance to CEA and resistance to CE depend on the hardness and the corrosive resistance of materials. The high hardness is the first factor of good resistance to CEA, strong corrosive resistance is the second factor. Meanwhile, the strong corrosive resistance is the first factor of good resistance to CE, high hardness is the second factor.
The ignition of both deal and fir blocks were tested with a bench-scale flashover test apparatus. Tests results showed that the bench-scale flashover test apparatus could offer a test environment similar to the true fire environment and tests executed with the apparatus had good repeatable property. Based on the cone calorimeter test results, a new ignition criterion of wood was presented in the paper. Ignition time of wood block in the bench-scale flashover test apparatus were calculated with the tested average temperature of the upper smoke layer and the new ignition criterion. The calculation results showed that the new approach was facile and available for the purpose of forecasting the ignition time of wood blocks in the bench-scale flashover test apparatus.
The strategy for forecasting the BP neural network was researched on the basis of the training-studying samples that were obtained in the orthogonal test of L9（34). The self-contained orthogonal sample was the basic training and studying cell. When others samples were added into the self-contained orthogonal samples or the self-contained orthogonal samples were cut down, the forecasting results were completely irresponsible. On the same test condition and orthogonal test type, the self-contained orthogonal sample with large information content could forecast that with small information content at high precision. A new test-design approach was put forward. Namely, the self-contained orthogonal sample was obtained through the orthogonal test, and then, the values of all other samples whose factors were the same as that of the self-contained orthogonal sample could be forecast in the BP neural network and its precision was considerable high. Therefore, the time and labors were enormously saved.
On the basis of the analysis work of many massive water resources and hydropower projects, and by using systemic view, the thesis analyses the composition of the system and the mutual relations among the elements. According to it, Linear Programming Model is constituted. The calculating result by the model is verified in real work. It s proved economic and feasible.
Most crude oils produced in China are waxy crude with poor flowability at ambient temperature. Pipelining waxy crudes by means of heating is a common practice. Some complex transient heat transfer problems are accompanied with hot oil pipelines. The state-of-the-art and recent advances in transient heat transfer research for buried hot waxy crude pipelines are summarized from the two aspects of the internal heat transfer from the oil to the pipe and the external heat transfer from the pipe to the surrounding soil. The factors governing the heat transfer of buried pipelines are discussed, and various methods involved to solve heat transfer through surrounding soil, analytically and numerically, are discussed and compared. The complex heat transfer with phase transformation and moving boundary for shut-down waxy crude pipelines is described and methods to tackle this complex heat transfer problem are introduced. The thermal and hydraulic interaction problem accompanied with transient flow in hot oil pipelines and their solutions are discussed. Problems needed to be further studied in transient heat transfer for buried hot waxy crude pipelines are pointed out.
Thin film lubrication (TFL) has been well studied as a new lubrication regime since the 90s of last century. TFL is a transition lubrication regime between elastohydrodynamic lubrication (EHL) and boundary lubrication (BL), which has specific lubrication features. The present paper reviewed the advancement of researches of TFL, which involves the origin of the TFL concept, advancement of measuring technique, TFL's film-forming features, investigation on its mechanism, and computation theories.
Mine disaster science is a systematic science for mine safety and disaster reduction. It is,compared with the previous unitary prevention and treatment of mine disaster, characterized by the comprehensiveness, prediction and economic nature. It involves 8 aspects of safety and disaster reduction,such as safety philosophy , safety economics ,etc. The research pattern embodies the principle of unity between the macroscopic and the microscopic. The research should be under the guidance of the system-theory. While exploring the preventing and treatment technology and method for the individual case of mine disaster,the research should be pitched into with multi discipline,at different levels and from different directions.