The analyses of characteristic parameters of modern low altitude air-defence missile weapon system are shown in this paper. These parameters can be used to represent the main specification of tactics and technicality. The synthetical evaluation of several foreign low altitude air-defence missile weapon systems is made, based on the measure of fuzzy function with weighted linear transformation. At the end of this paper the development tendency of weapon system in future is discussed in accordance with the quantitative analysis of the evaluation.
First this paper described the great challenge from the new era and its impacts on networks and indicated the huge capacity pressure faced by networks. Then, the paper discussed implications, effects and technical limits for the three basic laws which guide network era such as Moored Law, Optical Fiber Law and Metcalfe´s Law. Finally, the paper presented capacity evolution strategies for transmission links, transport nodes and service nodes in backbone networks, respectively.
This paper, from the view point of ecology, thoroughly analyses the surface source pollution of lakes, points out the crux of lake surface source pollution is the issue of resource utilization. So that the author suggests that in lake areas and lake water resource regions the construction of agricultural ecological projects should be carried out so as to reduce resource consumption and minimize pollutant discharge thus attain the goal of lake surface source pollution control and prevention. This paper also introduces the general procedures and major construction research contents of the agro-ecological project in Liuminying Village, Beijing and the large-scale eco-farming construction in Shengli Oil Field, and particularly introduces the significant role of agro-ecolog-ical construction project in economic development, environmental improvement, reducing of fertilizer and pesticide consumption, soil pollution elimination, control and prevention of surface source pollution.
The high slope for the permanent shiplock of the Three Gorges Project (TGP), excavated from the mountain body on the left bank, is one of the major technical issues of the Project construction. The excavation for the slope on each side is 170 m deep in maximum consisting of a 68m high vertical wall on its lower part. Several aspects are described in the paper for the permanent shiplock slope including the general description, design principles and outline,construction procedures, seepage prevention and drainage system, consolidation and support measures, stability analysis, deformation prediction, monitoring data verification as well as some significant scientific and technical achievements.
Incubating engineer is developing quickly in the world, the operation of which is complicated, involving productive factors and management. The essay aims at illustration of the incubating engineer in China, focusing on entrepreneur strategy, service strategy and venture capital strategy.
The trans-Yangtze traffic project plays an important role in the steady development of China´s economy in the 21st Century. In making choice of the transriver project scheme it is not wise to take bridge scheme as the only way out. Instead,equal stress should be laid on bridge and tunnel,so that both bridge and submerged tunnel can give full play to their own strong points in light of local condition.
This article starts with the research results that the performance of the ethylene production from hydrocarbons cracking is linked not only to the distillation range of the hydrocarbon distillate, but also its components. It raises a new concept of expanding feedstock sources different from the global trend of using lighter feedstock. The heavy distillates of Daqing crude, such as the third cut of the atmosphere tower, the first cut of the vacuum tower and the sweat distillate which is the by-product of the de-waxing of the vacuum second and third cuts, can be used as feedstock for ethylene units. This article summarizes the performance tests of the feedstock, the evaluation in a simulated cracker and the application results on industrial units. It proves that the feedstock ensures high ethylene yield and longer service lfie of cracker, thus is of obvious economic benefits.
Recently, there are quite a lot of discussions and proposals concerning the utilization of gasoline-ethanol mixture as fuel for automobiles. This paper analyzes the benefits and problems of this kind of use from the point of view of resources, cost, energy security, grain security and environment. The conclusion remarks are: utilization of corn-produced ethanol as fuel for cars could be one the measures for“digesting” the stale grain, but should not be the long term strategic solution to the liquid fuel shortage problem. This is because the concrete situation in China is different from USA and Brazil. Besides, according to the experience in USA, utilization of gasoline - ethanol mixture needs strong government subsidies, it is not reasonable form long term point of view. A preliminary assessment related to production of ethanol by enzymatic hydrolysis of cellulose materials is also presented in this paper. Finally, in order to mitigate the pressure of increasingly import of oil and ensure energy security in China, some strategic measures derived for sustainable development are proposed.
Some new types of electrodes for modern aluminium electrolysis cells are reviewed in this paper. They include inert cathode, inert anode, dipolar electrode and SiC side lining. Their functions and developing tendency are discussed.
Aiming at solving the problems of information retrieval and data integration over Internet, the idea of “active virtual server” is proposed, and a novel mechanism for data integration based on the virtual server is presented. Active virtual servers can be regarded as the uniform storage and processor of massive data over Internet, with the function of active services. By only using a unified extendable language (UXL) to wrap each kind of server with a uniform interface “active service coat”，the “active virtual server” can be constructed as needed without changing the original DBMS on the server. The above “coat” needs to be done only once for each kind of server, and can be exploited uniformly all over the Internet, hence it plays the role as Java Virtual Machine does.
The near beta forging for titanium alloys proposed by the authors has overthrown the conventional forging theory in the following two aspects: firstly, the material is heated and forged at 10〜15℃ below beta transus temperature and then water cooled; secondly, the heat treatment technology after forging consists of a high-temperature toughening treatment and a low-temperature strengthening treatment instead of the conventional aging treatment. Because of ingenious combination of phase transformation, defomation and strengthening and toughening theory, materials forged by the near beta forging do not produce an equiaxed microstructure or a basketweave microstructure as usually found in conventionally forged titanium alloy, but do produce a new trimodal microstructure, which consists of about 20% equiaxed alpha, 50%～60% basketweave formed by striature alpha and transformed beta matrix. The trimodal microstructure not only develops a new type of microstructure in addition to the existing four titanium alloy microstructures (i.e. equiaxed, bi-modal, basketweave and lamella), but also has the advantages that both the equiaxed microstructure and the basketweave microstructure have, so it shows excellent mechanical properties. It shows an increased high-temperature property, a high low-cycle fatigue property and a high fracture toughness without decreasing ductility and thermal stability. Moreover, it can raise the service temperature from 500℃ to 550℃ . The near beta forging is applicable not only to alpha-beta alloy, but also to alpha, near alpha and near beta titanium alloys. This method has been used to forge several engine compressor disks and some important structure components of missils and airplanes
On the foundation summing up existing intelligent conceptual design method, this article puts forward the research content, characters, path, and method of the conceptual design of extension for mechanical products. Around the core technology of intelligent conceptual design this article conducts research on the modelization method of extension design in function-principle-layout-configuration. It includes the function expression, function decomposition and synthesis, function illation and decision. Computers are utilized to simulate the human dialectic thought when resolve problems in this method. The living example shows that the extension method has been applied in the field of conceptual design for mechanical products. This method is of great significance to resolve the bottleneck problem in theoretic studying and engineering realization of intelligent CAD.
Starting from the trend of high speed rail development and taking the Nanjing-Shanghai section of Beijing-Shanghai high speed rail line for example, this article analyzed the tractive, braking and running resistant characteristics of high speed train by way of computer simulation. A brief calculation and comparison on socio-economic effect were made including runing speed, travel hours and traffic capacity of various trains at the speed between 180 km/h to 500 km/h. In addition the energy consumption of trains at different speed was compared .The proposal concerning the reasonable speed level of high speed rail traffic under the existing conditions was made.
Considering the conditions that TEDA used to be hungriness area without vegetation and without agriculture, forestry, livestock farming, etc. , to rely on, the new conception “allowable depth”, established in coastal area of TEDA with shallow groundwater and silt soft foundation, and the new techniques on water drainage by “shallow-dense type” underground level pipes were introduced. Technical constituent, advantage and implementation of the new techniques were discussed. From the view of sustainable development of afforestation ,technical measures for comprehensive tackling and control of the wilderness areas such as salt affected soils and their application in practice were introduced.
Based on the example of monitoring to the stability of the layered rocky high slope, base and foundation of the south tower of Jiangyin Bridge, the discipline of monitoring mesh design to its stability, the rational arrangement of monitoring spots, the embedding technology of hole with clinometer in fragmentary rock mass in high slope and the establishment of the monitoring and predictive model to the stability of high slope are elucidated. The discriminating discipline for the high slope stability based on the monitoring deformation result, and the quantitative evaluation method based on shear-slip, axial force and horizontal pushing force for the stability of high slope are suggested in the article.