On a lot of occasons in aerospace engineering, materials work in extreme situastions. Specific characteristics of materials are therefore required. Although some achievements have been accumulated in material research at home and abroad, deeper investigations are still needed on a more precise model and state equation corresponding to the damage of a specific material. These will include the aerodynamic heating of the advanced warhead reentering the atmosphere and the erosion of the space articles as well as the increase of the retreat value of the protection material caused by the coupling effect of both, the threat to space vehicles caused by high speed collision of space junk and micrometeors, and, in particular the damage and destruction caused by nuclear explosion and laser weapon which in fact is and the delamination caused by thermal shock waves of actual radiation. All of these belong to the response of materials to high speed collision.Electromagnetic materials such as radome material, infrared stealth material and EM shielding material are all EM functioning materials with EM wave of different lengths. As solid substances, they will respond to penetration, absorb and reflection. Different EM functioning materials possess different macroproperties of physical parameters. However, several parameters are general, such as dielectric constant, permeability and tangent of loss angle. Clear understanding of the relations among these parameters and the microstructures of materials will provide a scientific basis for materials design and innovation.
High density of driving power, fast response, high rigidity and high-precision are the advantages of hydraulic servo system, so it is widely used in aerospace. All of flight actuator and transmitting systems of today´s aircrafts are nearly driven by hydraulic systems. With the development of aircraft, especially of military aircraft, more demands are proposed to aircraft hydraulic system. In this paper, main developmental trend of airborne hydraulic system, especially for military aircraft, is summarized, and some research works on aircraft hydraulic systems in domestic and overseas are introduced. Light weight, small size, high-pressure, high power, variable pressure, intellectualization, integration, redundancy techniquue, and so on are the main trend of development of future aircraft hydraulic system. Especially, high-pressure, variable pressure hydraulic intelligent pump source system is very important for the development of future aircraft.
Catalytic technology is the basis of petrochemical industry. In this thesis, the technological progress of petrochemical enterprises promoted by the advance of catalytic technology was discussed, with examples .Meanwhile, petrochemical industry also raises a series of new subjects for the development of catalytic technology ： the technical revamping of existing plants require catalyst with higher activity ; the cleaning production process requires environmental friendly catalyst; the product structure adjustment requires excellent adaptability of catalyst; saving energy and lowering consumption and cost, as well as strengthening product competitiveness require continuous reduction of catalyst production cost and improvement of catalyst life, conversion rate, selectivity etc.
The paper mainly outlined the various efforts by which the forest resource inventory methods were improved in recent 20 years. These include, the estimation of forest stock, the area of the fragmentary woodland, and the research method of forest canopy density and the compilation of forest dynamic maps. Especially, after the methods mentioned above being applied in the practical forest resource inventory and analyzed on the basis of benefit, the suggestions on improving present inventory system were proposed. Furthermore, the development on the assessment and monitoring of the forest ecological environment and the forest disaster by means of remote sensing was mentioned.
In the light of the mentioned above, the forest remote sensing perspective of the 21 st century in China was predicted. The author putted forward to the main developing directions on forest remote sensing of the next century in China.
1 To include all kinds of new technology and form new technology system and join up with international
.The industrialization of remote sensing technology and guiding it into laws and regulations.
.The integration inventory system of GIS, GPS and RS.
.The assessment and application of new information resource, and the fusion of information.
.To unify the criterions (such as the forest classification system, inventory method) and join up with international, and share information.
2 To study the macroscopic conditions and functions through utilizing the superiority of the remote sensing
.The influences of the large scale forest distribution to the environment such as the temperature field, the soil condition and soil conservation, the local climate and hydrology condition, the relationship between the forest distribution on global scale and environment and the study of the function of forest from a new angle.
.The monitoring method of forest community of large scale such as low-resolution satellite data being calibrated by high resolution satellite data, the quantitative expression on the difference of the forest spatial arrangement.
.The expression and prediction of macroscopic forest phenomenon (such as community changing, the growth and decline of the forest resources, the forest disaster). The supporting model was provided for GIS and the foundation was offered for the disaster precaution as well as the reasonable distribution of the forest.
3 To integrate with the forest management
.The management precautions were monitored by utilizing the characteristic of the good temporal resolution about the space remote sensing data, and real-time renewing GIS data.
.With the emergence of the high-resolution satellite data and the development of high spectrum technology, the remote sensing expression of the forest details was probed. For example the discrimination of the varieties of species, the structure of the forest, canopy density and the possibility of estimating other stand description factors, so the advanced management to the forest and developing of sustainable forestry could be possible.
Petroleum will still be the major energy resources in the 21st century. Petroleum refining technologies will develope further. The refining technologies with broad prospects in 21st century would be the technology for production of the clean gasoline to reducing automotive emission, the technology for production of the low sulfur and low aromatic diesel, the technology for production of hydroprocessing lubricating base oils, the technology for conversion of heavy oils with hydrocracking and catalytic cracking, the technology for energy comprehensive utilization integrated with the residue processing, the information and process control technologies for modernization of refineries, etc.
This paper overviews a few methods of TMA (target motion analysis), such as only bearing TMA, multiple information fusion TMA, bearing-Doppler TMA, distance estimation with bearing and noise energy, matched-field location combined with TMA etc. We herein provide a new idea for the design of TMA functions in fully integrated and distributed submarine combat system.
We enhances the TMA functions from the point of view of submarine combat system, fully applying the information of multi-sensors and the operator´s subjective decisions in automatic and in manual modes. It will serve better in tactical decision making and provide more accurate results of target motion parameters. Compared with the normal design of TMA, this design has developed a function of target manoeuvre recognition, added the manual TMA function, and designed a display on which the operator can easyly observe TMA output, target motion and therefor improving track of targets.
Fiber reinforced metal laminates (FRMLs), a new type of hybrid composites, are finding wide applications in the aerospace industry. The material is featured by its excellent fatigue performance and damage tolerance. Reliable life prediction methods are required for the successful application of this material. For this purpose, a mechanism-based fatigue model was developed for the prediction of the fatigue lives of FRMLs under constant amplitude loading. The model was based on an analytical approach for the determination of the bridging stress over the crack faces by intact fibers.
The fatigue behaviors of glass fiber reinforced laminates (GLARE), including crack growth and delamination, under constant amplitude loading following a single overload were investigated experimentally, and the mechanism of the effect of an overload on the crack growth rates was identified. An equivalent crack closure model for predicting crack growth in FRMLs under variable amplitude loading was presented. All the models in this paper were verified by applying to GLARE under constant amplitude loading and Mini-TWIST load sequence. Good agreement was achieved.
One of the important problems for the Three Gorges Project is the stability for dam section No.1〜No.5 at left bank. The stability safety of dam section No.3 is studied with elasto — plastic Block Element Method (BKEM) in the paper. BKEM is a numerical analysis method. The basic unknown quantities of BKEM are the rigid displacements of the central points of block elements. Structure interface can be precisely and conveniently simulated in the method, and mechanical problem of discontinuous medium can be better. The correct ness of stability analysis of BKEM is proved with indoor model experiment and the two results are very consistent with each other. Finally, the result of stability analysis for dam section No.3 under several conditions is presented.
To ensure the high availability, the duplex-computer system with fault tolerance architecture is used in crucial projects. The similarites and differences of the two results from the duplex system have been the key difficulty of this domain. In this paper, there are great progresses in the analysis of availability, the judgement over of two results and the switch over two systems. The techniques have been realized in an important project with significant effect.
The harmonic series formula of the Earth´s disturbing potential is the most extensive applicable expression for the Earth´s gravity field model. At present, the resolution of the used geopotential coefficient model is 0.5°, and the complete degree and order is 360. Since the gravity data density and precision are very different everywhere, the model accuracy isn´t uniform. The improvement of model is necessary.. The method of the regional correction with frequency weight for improving a known model is a convenient and applicable method. Based on the OSU91A and EGM96 models and regional 15´×15´ △g and 5´×5´ △g, the improved models DQM99A and DQM99B to degree 720, DQM99C and DQM99D to degree 2 160 are developed. Their accuracy comparison is presented in this paper.
The present paper reviews the recent developments of electron-bombarded charge coupled devices (EBCCD) for low-light-level imaging. The EBCCD eliminates the complicated image transfer chain associated with conventional image intensifier fibrecoupled CCD (ICCD) by integrating a thinned back-illuminated CCD directly into the vacuum of the image tube in replacement of the phosphor screen. The photoelectrons emitted from the photocathode are “proximity focusing” or “sharp focusing” directly onto the electron sensitive CCD, and the video-signal occurs. It has been shown that the EBCCD image tubes offer nearly noiseless gain, high signal to noise ratio and excellent MTF and, for this reason, are superior to conventional ICCD approaches under all light level conditions. This paper will give a detailed description on the thinned back-illuminated CCD imager design and fabrication, such as CCD chip thinning and thinned CCD backside treatment, as well as the technical parameters of different kinds of inverter type EBCCD. The performance of the proximity type EBCCD, the inverter type EBCCD and ICCD will also be compared and analyzed. Finaly, the present paper shows that these new, high performance devices of EBCCD are in an advantageous position for many applications in low-light-lev-el surveillance imaging, high energy physics and medical diagnostics.
The universe of methodology for predicting the damage to structural materials and remaining life of process equipment is a branch of subject of a newly developing discipline - FORECASTING. The technique for predicting the damage to structural materials and remaining life of process equipment based on the use of experience of multi-discipline is a comprehensive technology in the field of modern technical management of facilities. Some contents of this technique have been selected among the subjects of emerging technologies to be developed over this century.
In this study, a series of new techniques for predicting the damage to structural materials and remaining life of porcess equipment have been developed, which are based on principles of approximate and plausible reasonings for uncertain parameters of fuzziness by fuzzy set theory; of quantitative metallographic technique by methods of stereoscopy and visual treatment technique.The technique proposed is of great significances for ensuring safe, high efficiency and long period operations in modernized large-scale and high parameter facilities of chemical, petrochemical, nuclear and electric power plants.
The main contributions of the technique proposed in this work are on engineering applications which provide major benefits in economics and society. The technique will be a bright future in use.
In this paper a new smelting process using fine iron ore powder and coal is proposed. The pecu-liarity is to eliminate the pollution in process improvement. In order to solve the sticking problem in conventional fluidized bed reactor, here we proposed a new technic by using non - isothermal fluidized moving bed prereduction reactor. Further, we are using the maximum utilization of energy principle instead of the second combustion principle. Three measures in our proposed process are： using fine iron ore as input; using the waste gas as chemical synthesis; using the reduction mechanism of lower part of blast furnace. With the progress of globalization of economy and technics, we proposed to try the possibility of using the venture capital to help the reformation of iron industry in china.
Optoelectronic technology is promoting the transform of information age, and its key component, optoelectronic devices are bring along a new industry-optoelectronic industry.
Quantum well laser is the third milestone on the semiconductor laser developing history. It has been called as ideal laser diode due to its advantages in all-important parameters.
The breakthrough of quantum well optoelectronic devices in China have been done by Chinese Academy of Sciences, with support by Chinese National Natural Sciences Foundation and Chinese National High Technology Developing Plans. They have been employed in the fields such as optical fiber communication, optical storage, optical display etc. The research teams have expanded from pure academic organizations and universities to industry .This will open up the trails for industrialization of optoelectronic devices.
Recently, Optoelectronic industry in China has formed in embryo. Several companies, who run business in the field of optical fiber communication, have output value beyond one hundred million RMB per year. As to noncommunication optoelectronic devices, it is on the momentum of swift and violent development. To put key components such as visible lasers and high brightness LED into domestic production will bring along industry of the pick-up, loader, even DVD player and DVD ROM, and the industry of full color display, traffic lamp, vehicle lamp and solid white light lamp. Their output value beyond ten billion RMB per year can be expected.
The present review is related to the progress of synthetic rubber industry in this century with special emphasis on the synthetic chemistry, which is the theoretic ground of synthetic rubber. It is forecasted that the living/controlled polymerization of all kinds, their transformation and matallocene system will still take the leading trend in the near future. The progress of the corresponding technology for the manufacture of synthetic rubber will be the gas polymerization process and the polymerization reactor will remain a hot topic to be investigated .
This paper summarized the advances and progresses in the investigation, classification, evolution of fauna, vertical distribution and evolution of adaptation of insect in Tibet, since 50s in this century. A new understanding and vision of fauna in Tibet were discussed in further. It was suggested that the Qinghai-Tibet Plateau can be regarded as a separate geographical region of fauna as equal to palaearctic region and oriental region.