High-power solid-state laser technology development has been conducted so far for more than thirty years for application to inertial confinement fusion. Over twenty laser facilities have been built with the output energy of about a hundred Joules at the beginning up to severa tens of thousands Joules later in USA, Japan, France, China, Bratain, Russia and so on. In recent years, a few powers have been working very hard to build huge facilities, such as the NIF in USA, the LMJ in France, the SG—Ⅲ in China and the Iskra-6 in Russia. Numerous advanced technologies have to be developed to support the construction of the facilities. However, the most challenging task is to study, from the point of view of engineering science, how to build such huge facilities featured with high cost, high technical risk, and a long time period, in a cost-effective manner.
This paper introduces the general situation of China-Brazil Earth Resources Satellite (CBERS), which is developed jointly by China and Brazil. Main characteristics of the satellite are compared with that of foreign same type satellites (Landsat, SPOT, IRS). The payload of some instruments, the service module, and the in orbit testing performance are described briefly. Finally the paper points out the design principle for the successive satellite.
The strategy of the western development of China, the exploit in the 21st century, has drawn the attention of every fields. Scientists, technologists and administrators have all seen the fragility of ecological environment and calamities in the western development. How to carry out the calamity protection and reduction, in other words, how to utilize the scientific and technological calamity reduction measures, is the focus now. According to the viewpoint of the author, in the ecological environment construction of the western region, the scientific and technological calamity reduction should be emphasized first, the thought of the industrialization of scientific and technological calamity reduction should be realized, and scientific and technological contents should be increased and spread out. Practical and realistic science spirits and strategic concept should be advocated. Scientific evaluation, calamity risks analysis and suitable ecological environment policy should be taken as the basis to ensure taking enough consideration for the calamity protection and reduction in, the planning, design, construction and other steps which is the key factor to the sustainable development of the western region.
The Three Gorges Project is the largest multi-purpose hydro-development project ever built in China and so in the world. The re-verification on TGP undertaken by 412 Chinese experts from 1986 to 1989, laid the foundation for the execution of the project construction. Since 1993, the construction has been commenced and proceeded smoothly according to the approved general schedule. The project investment is well controlled within the approved estimates of the preliminary design. The quality of the work already completed is satisfactory to the design requirements. Several important conclusions drawn from the re-verification have been proved preliminarily to be correct. And a series of major technical challenges, such as river closure of the grand channel, the construction of the deen water cofferdam, the excavation stability of the permanent ship lock with high slope, and the extremely high intensive concrete placement, have been met. The practice has fully proved the necessity and correctness of the previous scientific verification.
Due to the technology development and market demand, the PET industry has been developed very quickly in China, Asia and the whole world in the last twenty years. The focus of the PET industry has been moving to Asia and the Asia´s PET industry has been brought to a new stage. The technical development, market, production capacity and output of PET and polyester fibres industry at home and abroad are analyzed and forecasted to find out the gap between China and the developed countries in this field. The stress is placed on the development and research of the domestic PET engineering technology and the proven experiences. Some proposals are put forward.
The development of long-span spatial structures is characterized by the continual innovation of structural forms and the prompt support of theoretical studies. Several unconventional spatial structures designed by the author are introduced in this article as examples to demonstrate the efforts of Chinese engineers to create innovative structural forms in the recent two decades. Some theoretical studies by the author including the analytic theory of cable-suspended structures, the stability of reticulated shells, the seismic behavior and vibration control of reticulated shells, as well as the wind-induced response analysis of cable structures are also presented.
Since the coast of the Bohai Bay is a typical plain silty one, the problems about engineering sediments, such as fine sediment transportation and how to reduce silting amount for the port and waterway, have come across one after another in the construction of the Tianjin Port and the Huanghua Port of Hebei Province, the two largest artificial ports in China. On the basis of the data observed in situ in the coastal area of the Dakou River in the southwestern Bohai Bay, this paper analyzes comprehensively hydrodynamics, sediment trans-portation, sedimentation of the coastal beach and alluvial and silting evolution, which provide a theoretical basis for the strategic decision of “the shallow water used as the deep water” in the plain silty coast.
The choice of power supply radius for transformer substations is a complicated problem. A fuzzy geometric programming model of power supply radius under the fuzzy environment, including problems of soft constraints and fuzzy functions with fuzzy coefficients, is built in order to determine the best choice with less investment and lower energy loss. From the model built in this paper more information can be collected and more satisfactory results can be obtained compared with other static and dynamic optimum mathematical models such as controlling models and classical geometric programming ones.
The area method (AM) that minimizes the Gibbs energy by integrating, instead of differentiating, the Gibbs energy curve provides a sufficient condition for global Gibbs energy minimization rather than only a necessary condition provided by the flash equilibrium calculation method. However, it uses the method of exhaustion to search the positive maximum area, therefore requires a long calculation time. Here this method is modified as LSAM (local search area method), which is a repeated search shrinking vicinities of the liquid and gas equilibrium composition points located by previous rough search. The calculation time decreases to one over several thousands of AM’s or less. The experimental equilibrium data of benzene and propylene are used to demonstrate the merit of this method.
Knowledge base system (KBS) is an organization to store and manage a lot of knowledge. Extension knowledge representation (EKR) based on extension theory is presented in this paper. Two key concepts of EKR are the described——formal semantic of EKR and the formal representation of contradictory problem solving. The basic element of the former is knowledge matter-element model. In addition, the Specific Extension Inference (SEI) corresponding to EKR is also reviewed. The feature of SEI is correlative inference, which has been implemented by computer. Finally, the feature and the frame of extension knowledge base system (EKBS) are proposed. EKBS uses EKR and is an excess of traditional KBS. It is composed of goal system, condition system, common knowledge base, categorized knowledge base, inference machine and knowledge base management system.
The aircraft service air-ground-air environmental spectrum consists of two parts： flying environmental spectrum and ground parking environmental spectrum. To most military aircrafts, the ground parking time accounts for more than 90% of the aircraft service life. The service life of aircraft is greatly influenced by the severe environment of naval aircraft where there are 3-highs： high temperature, high humidity and high salt-fog corrosion. The service life of aircraft must be determined based on the environmental spectrum of aircraft service, in which factors such as flying time, calendar time and comprehensive service flying time are taken into account. As a typical example, based on the analysis of the axle neck crack of axial hinge in certain type of naval helicopter by utilizing an analytical method of structural fatigue, the overhaul life of the hinge is discussed in respect of flying time, calendar time and comprehensive service flying time.
This paper presents the new research achievements and experiment results of the application of 500 W CW YAG laser quenching for engine cylinder block, and then analyses the advantages of YAG laser quenching compared with C〇2 laser quenching. In computer controlling system, the concept of horizontal diamond number and vertical diamond number is proposed, new mathematics model is derived, and derived new technique of locally densified mesh is put forward. Laser quenching in high precision mesh is realized by software controlling .
The multiphase composite and the computer aided design of the ceramics are two significant trends in the development of the advanced ceramic materials in the 21st century. Mathematical models have been built for the description of the relationships between the mechanical properties and the material compositions of the multiphase composite ceramic tool material with the combination of both theoretical and experimental methods. The optimum compositions of the material have also been achieved by means of the computer aided optimization technology. Then, an advanced Al2〇3—SiC-(W,Ti)C multiphase composite ceramic cutting tool material is fabricated with hot pressing technology. The material is found to possess high comprehensive mechanical properties, which proves that the method proposed in the present study is reasonable and feasible for the design of multiphase composite ceramic tool materials.
A production scheduling solution involves a great deal of constrains, which determine the feasibility of the solution. So the study of the stability orientated to constrains is the focus of this paper. The definitions of the satisfaction degree of hard constrains and soft constrains are presented, and a concept of stable degree of production scheduling is proposed. A simulation result demonstrates the significance of the stability degree of scheduling in practical production processes.
In this paper, the concrete creep theory, compatibility equations, median theory and equilibrium conditions are used and the elastic aftereffect of concrete and creep shrinkage features of concrete restrained all around are considered to develop formulae of cross-section stress redistribution resulted from concrete creep and shrinkage. The formulae which are simple and convenient to use are applied to Wanxian Changjiang Bridge (420m in span) for the model test analysis of creep and shrinkage. The obtained results are compared with those of model test and the agreement between them is very good. The main factors to affect the stress of this type of bridge are indicated.
Liquid condensate is an important product of gas condensate reservoir, and its recovery should be both efficient and economic. This paper discusses economic development models of all kinds during the last two decades in the engineering field of gas condensate reservoirs, including reinjection with 75% dry gas recycling, dumpflooding of gas, nitrogen injection, water injection, water and gas alternating injection, C〇2 injection, etc. The results of the study indicate that these development models will be more effective than conventional pressure depletion methods and will be adaptable to complex cases of surface-underground gas condensate reservoirs.