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   Science & Technology Review
2011, Vol.29, No. 33
28 November 2011

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卷首语

Science & Technology Review. 2011, 29 (33): 3-3. ;  doi:
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Abstract ( 203 )
科技风云

Science & Technology Review. 2011, 29 (33): 7-7. ;  doi:
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封面图片说明

Science & Technology Review. 2011, 29 (33): 8-8. ;  doi:
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特别栏目

Science & Technology Review. 2011, 29 (33): 8-8. ;  doi:
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Science & Technology Review. 2011, 29 (33): 10-10. ;  doi:
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Science & Technology Review. 2011, 29 (33): 12-12. ;  doi:
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Science & Technology Review. 2011, 29 (33): 14-14. ;  doi:
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Science & Technology Review. 2011, 29 (33): 83-83. ;  doi:
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Science & Technology Review. 2011, 29 (33): 88-88. ;  doi:
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Science & Technology Review. 2011, 29 (33): 95-95. ;  doi:
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Science & Technology Review. 2011, 29 (33): 96-96. ;  doi:
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科技事件

Science & Technology Review. 2011, 29 (33): 9-9. ;  doi:
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科技工作大家谈

Science & Technology Review. 2011, 29 (33): 11-11. ;  doi:
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Exclusive

Science & Technology Review. 2011, 29 (33): 15-19. ;  doi: 10.3981/j.issn.1000-7857.2011.33.001
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Abstract ( 569 )
Articles

Experimental Processing of Chromium-contented Acid Wastewater with the Saline-alkali Soil

LI Xuqian;GUO Lili;LI Hongyan;LU Feng
Science & Technology Review. 2011, 29 (33): 20-25. ;  doi: 10.3891/j.issn1000-7857.2011.33.002
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Abstract ( 324 )
In order to research the saline-alkali soil ameliorating status and species changes of chromium during comprehensive utilization of chromium-contented acid wastewater with saline-alkali soil, permeation and pressure equipments are adopted to simulate the process of chromium-contented acid wastewater permeating through different pH saline-alkali soils. By the assaying and analyzing some indicators of pH, ORP, ESP, sum of Ca2+ and Mg2+, organic matter, and the different factions of Cr, test results show that the course of chromium-contented acid wastewater permeating through saline-alkali soil makes saline-alkali soil tend to be neutral. And it would not reduce soils autologous organic matter and the levels of Calcium and Magnesium. The overall migratory capacity of Cr in the acid waste water is weak. It states that the saline-alkali soil has an obvious effect on the chromium-contented acid wastewater treatment, and the saline-alkali soil is also ameliorated.

Screening and Identification of Sphingobacterium sp. for Wool Enzymatic Scouring

ZHENG Laijiu;XU Chunyuan;DU Bing
Science & Technology Review. 2011, 29 (33): 26-29. ;  doi: 10.3981/j.issn.1000-7857.2011.33.003
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Abstract ( 297 )
Chemical wool scouring method was widely used in the initial processing of the wool fiber material. This method depended on surfactant and inorganic and required high temperature and strong mechanical action. Huge amount of water and energy were consumed, and scouring wastewater was discharged in nature, causing serious environmental pollution. There were chemical residues on the surface of wool fiber, affecting the quality of scoured wool fiber and easily causing damage to fiber. In order to reduce environmental pollution and chemical residues of chemical wool scouring, the enzymatic scouring technology is researched, and the scouring strain that overproduce lipase is selected from the soiled surface of raw wool identified as Sphingobacterium sp. based on morphological, 16S rDNA sequencing, physiological, and biochemical tests. By means of Rhodamine B chromogenic medium fluorescence experiments, the H/C value of Sphingobacterium sp. is 2 (H/C is the ratio of Fluorescent ring diameter to colony diameter), and its enzyme activity could reach at an enzyme-producing peak (101.67U/mL) at 30℃ after 11h incubated. After verification experiment of enzymatic scouring, the greasy rate of enzymatic scoured wool fiber is 1.031%, therefore the lipase-producing strain, that is, Sphingobacterium sp. possesses the good applicability for the enzymatic scouring.

Green Construction Evaluation System of Thermal Power Projects

CHEN Zhihua;FAN Lijun
Science & Technology Review. 2011, 29 (33): 30-35. ;  doi: 10.3981/j.issn.1000-7857.2011.33.004
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Abstract ( 262 )
Green construction has been vigorously promoted in China; however there is still no unified standard for the evaluation system of green construction. Furthermore, the evaluation of industrial projects is not involved so far. Thermal power project construction is comprehensive; it covers a large area and set, its plane is complicated, involves large volume of equipment as well as concrete elements, and needs large equipment lifting, etc. These characteristics make the project waste resources, and pollute environmental that is worse than the other projects during the construction. Therefore, for controlling the energy consumption and environmental pollution caused by thermal power project, the green construction is necessary. On the basis of Green Construction Guide, combined with the characteristics of thermal power projects, from aspects of construction management and construction site management technology, the indicators that reflect the requirements of the green thermal power project involving four sections and one environmental protection are established, and the application layer analysis is used and the comprehensive assessment model for green construction is given.

PFC3D Simulation of the Strength Parameters for Jointed Rock Mass in Gold Ore of Luoshan and Its Applications

ZHAO Guoyan;DAI Bing;DONG Longjun
Science & Technology Review. 2011, 29 (33): 36-41. ;  doi: 10.3981/j.issn.1000-7857.2011.33.005
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Abstract ( 299 )
The failure process of rock mass with different angle beddings in compression and tensile tests was simulated by using PFC3D numerical simulation. According to the displacement and speed distribution of the particles, the failure mechanism of rock joints is put forward, and the strength and deformation characteristics of jointed rock masses are compared with that under the laboratory conditions. The results show that the uniaxial compressive strength first decreases with the increase of angle beddings in the range of 0-60°and then increases with the increase of angle beddings in the range of 60°-90°; the tensile strength decreases with the increase of angle beddings in the range of 0-90°. The results of the PFC3D numerical simulation are in perfect agreement with the test results, and provide a new way for the determination of the strength parameters of jointed rock masses in practical engineering.

Design and Simulation of an Improved Digital AGC System

JIANG Kun;WANG Yuanqin;ZHAO Chengbin
Science & Technology Review. 2011, 29 (33): 42-46. ;  doi: 10.3981/j.issn.1000-7857.2011.33.006
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Abstract ( 343 )
A new digital AGC system with independent adjustable control accuracy and settling time is proposed based on feedback logarithmic AGC loop for the conflicting issues between control accuracy and settling time in traditional AGC system. By smartly splitting the single loop gain factor to two independent loop gain factor, one is used to control steady-state accuracy, the other is used to control settling time, the independent adjustment of settling time and control accuracy is achieved. AGC loop equation is derived. Analytical expression of time constant and control accuracy is solved. Performance of the power estimation methods between sum of squares and maximal values of slip windows are analyzed in low SNR, which indicates that sum of squares power estimation method has better performance in low SNR. The computer simulations of the AGC system are given using sum of squares power estimation method. The results indicate that the settling time of the system don't change with the input signal amplitude, the settling time and control accuracy can be adjusted according to the actual engineering requirements, the system has excellent performance even in low SNR.

Reactor Design of Mobile Fast Pyrolysis Apparatus and Its Simulation for Fluidization

SI Hui;WANG Xiao
Science & Technology Review. 2011, 29 (33): 47-51. ;  doi: 10.3981/j.issn.1000-7857.2011.33.007
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Abstract ( 332 )
Fast pyrolysis is seemed to be an important approach to produce the energy from biomass. Bio-energy offers a clean, renewable source of energy. Its impressive potential makes this technology develop fast. Mobile fast pyrolysis apparatus works as a mobile plant. It could convert the biomass into bio-oil with high quality which will be used to produce other products. The mobile apparatus is designed to have the mobility in order to collect the biomass dispersed in the fields. In this way, the cost of raw materials transportation will be largely reduced. The reactor which is the key component of this apparatus is designed. This new type of reactor is a combination of combustion chamber and reaction space. An annular reacting area is provided by the special structure of the reactor. This construction makes the reactor small enough to seize the space need by the whole equipment. The software of Fluent 6.2 is used for the digital simulation of fluidization condition in the traditional reactor and the new one. The results show that the fluidization effects of these two reactors are almost same under the cold condition. The new type of reactor is proved that is adequate to the job. Comparing with the traditional reactor, the new one has the characteristics of high thermal efficiency, compact, easy operation, etc, which make it well suite to the mobile operation.

Improved PSO-LSSVM Productivity Prediction Model for the Fractured Horizontal Well in Volcanic Gas Reservoir

WANG Peixi;ZHANG Jing
Science & Technology Review. 2011, 29 (33): 52-57. ;  doi: 10.3981/j.issn.1000-7857.2011.33.008
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Abstract ( 349 )
The existing productivity prediction model of fractured horizontal well in volcanic gas reservoir has more influence factors, less real samples, and incomplete parameters, therefore, it is difficult to accurately predict the productivity by using conventional methods. In order to quickly and effectively make certain of the productivity of fractured horizontal well in volcanic gas reservoir with existing data, the influence factors are determined by using Grey Relational Analysis(GRA), and the sensitivity of factor weights is considered to amend the algorithm. The improved PSO-LSSVM productivity model is established based on the parameters of Least Squares Support Vector Machines (LSSVM) which are optimized by Particle Swarm Optimization (PSO) algorithm. This model not only makes full use of the characteristics of the LSSVM small samples, which possess the strong learning ability and simple calculation, but also takes the advantages of fast calculation and better global searching ability of PSO. Comparing the PSO-LSSVM model with the BP-LM model, the improved PSO-LSSVM model has less iteration times, higher calculation precision, and more accurate predict results.

Numerical Simulation of Nitrogen Foam Stabilizing Oil Production and Controlling Water Cut Technology for Offshore Oilfield

GONG Ruxiang;LI Xiang;LI Xiaobo;JIN Fanghong
Science & Technology Review. 2011, 29 (33): 58-61. ;  doi: 10.3981/j.issn.1000-7857.2011.33.009
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Abstract ( 274 )
The oilfield studied in this paper is a typical block bottom water reservoir. The whole oilfield is in a high water cut stage. Most wells are water-coning production wells, so the key to maintain a stable oil output in the high water cut period is how to control the water-coning . We take one well of the oilfield as an example, to study the nitrogen foam stabilizing oil production and controlling water cut technologies with the numerical simulation method to provide technical support for the process scheme implementation. On the basis of historical data matching, the injection and production parameters of the nitrogen foam stabilizing oil production and controlling water cut technology are optimized. The results show that the optimum injection and production parameters are as follows: continuous infiltration with injection volume of 45×104 m3, gas-liquid ratio of 1:1, shutdown days of 3 days, and daily fluid production rate of 900m3/d.
学术争鸣

Potholes on Hilltops is Not the Evidence for Quaternary Glaciaer in Eastern China

ZHANG Yuxu;LIU Lian
Science & Technology Review. 2011, 29 (33): 62-68. ;  doi: 10.3981/j.issn.1000-7857.2011.33.010
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Abstract ( 532 )
Whether or not there was Quaternary glacier in eastern China is a question with a significant impact, which has been debated for decades by the geological and geographical scholars of China. Potholes were considered as the important evidence of Quaternary glacier in eastern China in some papers. However, it is considered that the hilltop is always in the environment of denudation, therefore the potholes on hilltops could not be the ancient stuff, while they should be the result of modern and contemporary processes. And the ice-induced theory could not explain the geological characteristics of the potholes on hilltops, and the formation mechanism is also hard to believe. It is considered that the potholes on hilltops are formed by differential weathering. The original small and/or sallow pit accumulated rainwater, then the feldspars in the granite began to accelerate decomposing, comparing with the anhydrous naked ridge, the weathering rate was significantly quick, leading the pit deepened and enlarged. It is found that a shallow pit (4 to 5 cm deep) in western Inner Mongolia has had typical characteristics of potholes, i.e. small mouth, large belly, and flat bottom; many of the potholes located on the margin of the cliffs were no longer deepened and enlarged, because the pot walls were eroded through and could no longer contain water; and in Xintai, Shandong Province, the characteristics of a pothole on top of the Qingyun Mount show that it has experienced two stages evolution. These phenomena show that the potholes on hilltops are the products of gradually enlarged and deepened. The huge pothole in the Bailongtan (White Dragon pool) in Yanqing, Beijing was observed, the pothole is just located in the turning and changing narrow zone of the river, and it is considered that was formed by the flood swirl. Therefore, the potholes, either on hilltops or in valleys,could not be used as the evidence of paleo-glacier.
Reviews

The Secret in Geospace: A Broad and Dynamic Region of Radiation

CHEN Jiasheng;LYU Ling-Hsiao
Science & Technology Review. 2011, 29 (33): 69-71. ;  doi: 10.3981/j.issn.1000-7857.2011.33.011
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Abstract ( 289 )
The Earth's magnetospheric cusp is a key region for transferring the solar wind energy, mass, and momentum into the Earth's magnetosphere. Recently, a broad and dynamic region of radiation in the geospace is discovered which is centered at the Earth's magnetospheric cusp. The size of the region is up to 10.5Re (Earth radii) in the depth, the size is 6Re in the latitudinal direction and is bigger than 10Re in the longitudinal direction at an altitude of 7-8Re. When spacecraft was crossing through the new region of radiation, it observed orders of magnetude enhancements for both electromagnetic fluctuations and energetic charged particle intensities. When solar wind charged particles access the cusp, the diamagnetic effect further tears wide and deep magneticholes in the magnetosphere and further transfer the solar wind energy into the electromagnetic fluctuation power. The strong electric field fluctuations could efficiently energize the cusp charged particles by cyclotron resonant acceleration, resulting in a broad and dynamic region of radiation centered at the cusp. The ion phase space densities in the region of radiation could be two orders of magnitude higher than that in the outer radiation belt at a given magnetic moment. The region of radiation is observed on both open and closed geomagnetic field lines. It could extend to low-latitude, overlapping with part of the outer radiation belt and providing a direct particle source for the outer radiation belt.

Review on Forest Health Evaluation Index System

SHEN Jianbo;LEI Xiangdong;SHU Qingtai;ZHANG Huiru
Science & Technology Review. 2011, 29 (33): 72-79. ;  doi: 10.3981/j.issn.1000-7857.2011.33.012
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Abstract ( 292 )
Forest health assessment is currently a hot research issue both at home and abroad, for the evaluations of forest conditions and forest resource management. However, there are various forest health evaluation index standards in use. The paper analyzes the types and frequencies of forest health evaluation indexes based on a literature review. Results show that the indexes used abroad are mainly related with the inherent characteristics of forest ecosystems, while, the indexes used in China cover both natural and socioeconomic aspects and are much more numerous as compared to those in international uses. Some evaluation indexes are not workable and their definitions are not very clear. A uniform and standard forest health evaluation index system should be developed, and the corresponding thresholds can vary with different regions, forest management objectives and forest types. This study provides a reference for the development of a forest health evaluation index system in China.
科技评论

Science & Technology Review. 2011, 29 (33): 80-80. ;  doi:
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主编心语

Science & Technology Review. 2011, 29 (33): 83-83. ;  doi:
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走向职场

Science & Technology Review. 2011, 29 (33): 84-84. ;  doi:
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