28 January 2012, Volume 30 Issue 3

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  • ZHU Yu;SU Qing;CHEN Guangren;DAI Li
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    Based on the event every year for selecting the annual important advances about science, technology and engineering held by our publishing house, with the same principles of evaluating within each branch, putting quality before quantity, and giving facts in time order, 10 important scientific achievements, 10 important technological achievements and 10 important engineering achievements in China in 2011 were selected from a lot of scientific news in Science and Technology Review, other key academic journals and scientific newspapers. These achievements were introduced by the Editorial Department of Science and Technology Review.
  • Articles
  • YAN Feng;ZHANG Qingming;BAI Chunhua;CHEN Jian;WANG Zhongqi;LI Jianping
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    To study the action of high-energy explosives in the underground explosion a measurement system for soil pressure is designed, including stress-testing methods and experimental systems. The experimental results show that the pressure measurement system can well record the explosions, as has been done in China and Turkey, as well as the pressure changes and the development processes. Through the analysis of the pressure waveform and the spectrum, we obtain, for the same explosive and the soil media, the stress wave peak value, the principal frequency and the frequency bandwidth against the distance.
  • AN Zhen;LI Jinshan;HU Rui;TANG Bin;WANG Jian;YAO Caogen
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    Based on the Explicit/Standard modules of software ABAQUS, a 3D finite element model of Ni-Cr-W-Mo superalloy workpiece with strange shape multi-pass is built. The distribution and variation features of stress-strain, hot spinning regular pattern, and common defects are investigated in the forming process for the Ni-Cr-W-Mo superalloy workpiece with strange shape. The results show that by taking some factors, such as the defects forming, minimizing forming pass, etc into account, the spinning gap should be bigger than 3.7mm. The gap between blank and mandrel is quite small at the region near the central axis, however, the gap near the oral part of workpiece increases enormously.
  • WU Zhu;CHEN Yi;WANG Jianzhao
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    The process of zinc oxide production could be divided into two processes including fire and wet. French process is an important method for indirect ZnO production. A French ZnO furnace in Zhejiang Province is taken as the research object, the heating process and structure of the furnace are optimized and confirmed by means of numerical simulation and are tested through implementation, which effectively enhances thermal efficiency and extends the life-span of the furnace. By using numerical simulation of fire tunnel and combustion chamber, the effects of both burner type and furnace structure on the temperature field, flow field, and concentration field in the furnace are simulated and analyzed. Several reasonable optimization methods and reformation advices are put forward, and the simulation results are consistent with the field test results quite well. The furnace is reformed according to the simulation results, gas burner is changed from atmospheric to premixed, and the device for the air-fuel ratio adjustment is used to control the ratio of air and fuel, then the fire tunnel is changed from vertical structure to flaring structure. After these technique transformations as mentioned above, the gas consumption for one ton ZnO decreases from 240Nm3 to 192Nm3, and for each single day, 360Nm3 natural gas is saved, the average production of ZnO increases from 7.5t/d to 8.0t/d, and the life-span of the inner and outer crucibles of the furnace increases from three months to six months. The economy benefit due to the energy saving reconstruction is up to fifty thousand Yuan RMB per furnace per year.
  • ZHANG Yeqin;WANG Junli;ZHONG Ping;LIU Liyu
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    The effects of quenching temperature, cooling method and tempering temperature on the microstructure and mechanical properties of 38CrMoAlA steel have been studied through a series of heat treatment process tests. The experiment has measured the mechanical properties of the steel in different heat treatment conditions. The mechanical tests include tensile, impact and hardness test. The experiment has also measured the continuous cooling change curve of the steel, and analyzed the microstructure of the steel under different cooling rate and different temper conditions. The results of tests show that the effect of quenching temperature on mechanical properties of the steel the impact is not big when quenching at the temperature between 900℃ and 1000℃. Because of different cooling intensity of quenching medium, different cooling methods lead to different microstructure, and thus affect the mechanical properties of the steel. The effect of tempering temperature on the microstructure and mechanical properties of the steel is the most remarkable. When tempered at the temperature between 100℃ and 400℃, it behaves temper brittlement. While tempered at about 620℃, it can get a good combination of strength and toughness. Therefore, choosing the heat treatment process of quenched by heating to 940℃, holding at temperature for one hour, cooling in oil, and tempered by heating to 620℃, holding at temperature for five hours, cooling in oil, 38CrMoAlA steel can get the best property.
  • LI Tao;FENG Ziping;SONG Wenji;GAO Rixin
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    Water is the essential thermal media for cooling equipment, central air-conditioning, boilers and others to cool or store energy, but the storage of water in the system for a long time will cause not only the growth of bacteria and algae, but also the corrosion of the equipment surface. It was reported that electromagnetic water treatment would kill bacteria and algae, remove dirt and inhibit metal corrosion. In this paper, an experiment platform composed by stainless steel sink, electromagnetic water equipment, filter column, circulating pump is used to evaluate the effect of electromagnetic water treatment on the water environment and metal equipment, by tracking the contents of calcium carbonate and dissolved oxygen in the water under the action of the electromagnetic treatment, and analyzing the chemical composition of the sediment in the filter column produced in this process. The experiment results show that the electromagnetic water treatment has the sterilization function, but it also promotes the corrosion of the surface of metal equipment.
  • QI Yadong;ZHAN Jianfei;LI Xiaoming;MA Teng;LI Jilin;WU Liangjun
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    By means of experimental physical simulation, the influence of stress variation on the permeability of fractured and non-fractured ultra-low permeability sandstone cores were researched, the permeability variation of the two types of cores were compared with each other, and the stress sensitivity characteristics of the fractured and non-fractured reservoirs were summarized. The results show that for both fractured and non-fractured reservoirs, the lower permeability is, the stronger sensitivity of permeability stress is. For non-fractured reservoirs, when the reservoir permeability is lower than 2×10-3μm2, the sensitivity of permeability stress is strong and the strength increases rapidly as the permeability decreases, and when the reservoir permeability is higher than 5×10-3μm2, the sensitivity of permeability stress is weak; the fractured reservoirs stress sensitivity is much stronger than that for non-fractured ones; and the permeability loss of fractured reservoirs caused by the effective stress increase is 2—3 times of that for non-fractured reservoirs; and the permeability is unable to recover completely after the effective stress decreases, and the permeability loss of fractured reservoirs is 5 times of that for non-fractured reservoirs. The research findings are useful for engineers to determine the development strategy for ultra-low permeability sandstone reservoirs.
  • HUANG Wanpeng;GAO Yanfa;WANG Dongxu;LI Xuebin;WANG Zhengze
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    This paper proposes a new kind of aquifer criterion to determine the permeable fractured zone's height after working face mining. The new criterion can be explained as follows. It is shown that if the permeable facture zone's height is monitored by the measuring instrument, one may see the designed drill break across the aquifer upon the fractured zone. Then the confined water would flow down through the drill. This phenomenon shows that the permeable fractured zone has not been developed to the height of the aquifer layer. So, whether the aquifer layer is destroyed may be taken as a new kind of criterion to determine the height of the permeable fractured zone. With this new criterion, one must analyze the layer relationship between the permeable fractured zone and the aquifer based on the reasonable prediction of the permeable fractured zone's height. According to the regression analysis of measured results of some coal mine's permeable fractured zone height, the new criterion is shown to be more accurate and safer in determining the permeable fractured zone's height.
  • XIE Guanbao;LI Sanguo;LI Yongjie
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    With the recently development of electronic technology, the cased hole formation resistivity logging has been rapidly developed in order to discover the distribution of residual oil in the middle or late exploitation stage of the oilfields. The logging technology has many advantages that include the monitor of residual oil through casing, tapping potential of old well, the determination of submerged oil layer, and the production dynamic monitoring. They have all received quite good application effects. However, the effective signal during the acquisition process is in the level of nano-volt, the casing, measuring frequency, measured from the electrodes, cement mantle, and the heterogeneity of cased hole all will make measured signal distort, the cased hole resistivity data in the pre- processing must be corrected for these factors. Based on the logging information characteristics of the Russian ECOS-31-7, the filtering and interpolating methods for the original discrete data have been analyzed. Furthermore, the correction methods, such as the heterogeneity of casing, cement mantle, and cement quality, have been discussed. The processing results of the original data by means of actual casing measurements in the oilfield indicate that the method is feasible and effective.
  • YANG Chunlu;MA Xiping;HOU Wei;LI Fayun;LIU Qiang;LI Yue;CHENG Zhihui;KONG Weijing
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    To reveal the impact of human disturbance on the riparian zone soil, the riparian zone of Xi River, where is frequently disturbed by human in recent years, and is located in Benxi City, Liaoning Province, has been selected as the research object. By using field investigation and laboratory analysis methods, the soil physical and chemical properties of the 27 points at three different sampling depths of 0—20cm, 20—30cm, and 30—40cm were studied. The results indicate that the riparian zone soil of Xi River has a hard soil matrix and a poor soil structure. The values of bulk densities are generally high, and total porosity of that is generally low. The soils are neutral or alkalescent. Contents of soil total phosphorus are generally high; however, the available phosphorus is extremely low. The value of organic matter and total nitrogen is very different in different points, and there is a significant relationship between the two properties. In the general, the property values in different points is significantly different, however it is insignificantly different among the three different sampling depths at the same point. Research results show that the frequent human interference with the riparian zone soil of Xi River has the serious influence on the soil natural layer, and the restoration process for the zone needs a long period.
  • Reviews
  • ZHONG Jian;WU Chao
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    The adhesion and removal of micro-particles are very important for the quality control of many industrial processes. They are also directly related to the environmental pollution and occupational health. The study on micro-particle adhesion force measurement techniques is helpful to control micro-particles adhesion pollution and remove micro-particles on the surface. In order to understand the progress in the micro-particle adhesion force measurement techniques, the studies on this area are reviewed. Based on the databases (Ei Compendex, Ei Inspec, and Elsevier Science), three subject words (Particle, Adhesion, and Measurement) are used and about 150 papers in the area published in the years from 2001 to 2010 are found from the search results. The statistics analysis on the publication time, authors' countries, and topics of measurement techniques is conducted. Various micro-particle adhesion force measurement techniques including the AFM detachment technique, the micromechanical detachment technique, the centrifugal detachment technique, the electrostatic detachment technique, the vibration detachment technique, and the laser detachment technique are discussed. The advantages and disadvantages of those micro-particle adhesion force measurement techniques are compared with each other. In the end, the development directions on this field are pointed out.
  • LUO Liping;QIN Jiayin
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    With the rapid growth of wireless communication services, the radio spectrum is becoming increasingly overcrowded. Cognitive radio is regarded as a promising approach to alleviate the spectrum shortage and improve the spectrum utilization. Thus, the cognitive radio recently becomes one of hot research sports in wireless communications area. Based on the extensive investigation, the research progresses made in cognitive radio during the past ten years are reviewed from the aspects of spectrum policy evolution, network structure and standard development, and the related work. The relevant literatures and the famous international research institutes that focus on the field of cognitive radio are listed. Then, the application prospects of cognitive radio are presented. It is shown that cognitive radio could provide spectrum resource for the emerging applications, such as smart grid networks, wideband cellular networks, public safety networks, and medical body area networks. The cognitive radio technology is able to promote the development of these new emerging communication services. In summary, cognitive radio has wide application prospects and is expected to be one of the 5G communication standards. Furthermore, the future research directions in the area of cognitive radio are put forward, which include robust spectrum sensing and cognitive relay networks based on multiple user cooperation. Therefore, a good guidance for the researchers in the field of cognitive radio is provided.