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   Science & Technology Review
2011, Vol.29, No. 29
18 October 2011

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卷首语

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

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

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

Science & Technology Review. 2011, 29 (29): 8-8. ;  doi:
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Science & Technology Review. 2011, 29 (29): 10-10. ;  doi:
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Science & Technology Review. 2011, 29 (29): 12-12. ;  doi:
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Science & Technology Review. 2011, 29 (29): 13-13. ;  doi:
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Science & Technology Review. 2011, 29 (29): 14-14. ;  doi:
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Science & Technology Review. 2011, 29 (29): 43-43. ;  doi:
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Science & Technology Review. 2011, 29 (29): 88-88. ;  doi:
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Science & Technology Review. 2011, 29 (29): 95-95. ;  doi:
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Science & Technology Review. 2011, 29 (29): 96-96. ;  doi:
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科技事件

Science & Technology Review. 2011, 29 (29): 9-9. ;  doi:
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Abstract ( 201 )
科技工作大家谈

Science & Technology Review. 2011, 29 (29): 11-11. ;  doi:
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Abstract ( 273 )
Exclusive

Science & Technology Review. 2011, 29 (29): 15-21. ;  doi: 10.3981/j.issn.1000-7857.2011.29.001
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Abstract ( 297 )
Articles

Analysis and Comparison of Multiple Beam Lidars for Wind Measurement

TAN Ying;;WU Xiaying;DING Ying;YI Fan;
Science & Technology Review. 2011, 29 (29): 22-26. ;  doi: 10.3981/j.issn.1000-7857.2011.29.002
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Abstract ( 341 )
The multiple beam wind lidar measures the vertical profiles of wind velocity by tracking the particulate structures, or the spatial variations in the particulate concentration (or more precisely, in the scattering intensity). The results depend upon the large-scale particulate structure and the assumption of frozen turbulence. The lidar device is relatively simple and not expensive. In this paper, two methods of the multiple beam lidar for the wind measurement are analyzed and compared. One method uses the correlations of lidar signals from multiple lines of sight. Another method uses the ratio of Fourier transforms of two multibeam lidar signals. The latter enables the measurement of the horizontal wind vector using a relatively fast computational algorithm.

Spacecraft Potential Control and Potential Monitor During Spacecraft Docking

GUAN Yibing;WANG Shijin;LIANG Jinbao;LIU Chao;
Science & Technology Review. 2011, 29 (29): 27-31. ;  doi: 10.3981/j.issn.1000-7857.2011.29.003
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Abstract ( 353 )
The different potential between two low orbit spacecrafts is a serious safety problem for the spacecraft docking. The charging mechanism of the spacecraft in the ionosphere plasma is analyzed, and the equivalent circuit model in physics is educed. Based on that, the active potential control method for the International Space Station (ISS) is analyzed and two different methods that make sure of the spacecraft is immune from different potential are proposed. In the end, the solution for the spacecraft potential monitor including the Langmuir probe and the surface potential monitor during the docking is advanced.

Temperature Computational Method of Complicate Bore Frame Gas Well Wellbore with High Temperature and Pressure

XIAO Xiangjiao;JIANG Hanqiao;LIU Yuewu;ZHANG Jianye;WAN Yizhao;WANG Xiaopei;OUYANG Weiping
Science & Technology Review. 2011, 29 (29): 32-37. ;  doi: 10.3981/j.issn.1000-7857.2011.29.004
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Abstract ( 481 )
The source gas wells for the west to east gas pipeline are mainly high temperature and high pressure gas wells. The production capacity of these gas wells highly depends on the pressure and temperature of well bottom. Temperature in the production process plays an important role. In order to ensure normal production of high-temperature and high-pressure gas wells, in depth study of wellbore temperature and pressure must be carried out. There are many mature research results involving wellbore pressure, however, the study on well bottom temperature is still immature, and especially the impact of complex wellbore on the wellbore temperature has not been reported at home and abroad. Based on the classic Ramey wellbore temperature model, two kinds of mathematical models for calculating the well wellbore temperature distribution in the well with complex structure wellbore are built. The models include the one calculating temperature from well bottom to wellhead and the other calculating temperature from wellhead to well bottom. By comprising with the data of field test, the calculation errors are given, and the impact of the wellbore structure on wellbore temperature distribution is analyzed. The results indicate that the calculating result by using the model from the well bottom to the wellhead is better than that by using the model from the wellhead to the well bottom in the temperature distribution calculation.

Preparation and Swelling Dynamics Research on Polyacrylamide/methyl Cellulose Semi-interpenetrating Polymer Networks

CHEN Qiang;ZHU Lin;SU Xiuying;AN Huiyong;
Science & Technology Review. 2011, 29 (29): 38-43. ;  doi: 10.3981/j.issn.1000-7857.2011.29.005
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Abstract ( 307 )
Polyacrylamide/methyl cellulose semi-interpenetrating polymer networks (PAM/MC semi-IPNs) were prepared by aqueous radical polymerization at room temperature and APS, MBA, and TEMED were used as initiator, crossliking agent, and accelerator, respectively. The structure of hydrogels was characterized by FT-IR. The influence of MC content and temperature on hydrogel appearance, equilibrium swelling, and swelling kinetics of semi-IPN was investigated. The FT-IR spectra show that the peak of aminoⅠfor PAM is shifted from 1632cm-1 to 1650cm-1; the fact indicates that there is a strong hydrogen-bonding interaction between PAM and MC. The color of hydrogels becomes muddier from transparent to milky-like as MC content increasing. The equilibrium swelling of the series of hydrogels is enhanced as temperature increasing. However, at the same temperature, the equilibrium swelling of hydrogel is suppressed as MC content increasing. In addition, the size of semi-IPN hydrogels does not change much as temperature rising, it is inferred that the phase transition of MC at higher temperature does not lead to volume phase transition of semi-IPN hydrogel. All the hydrogel samples show rapid swelling properties before 100min, the swelling becomes slow down after 200min, and eventually the swelling approaches the equilibrium. The data of diffusion index (n) and swelling rate (k) infer that the temperature has great influence on the diffusion mechanism and swelling rate, whereas the hydrogel that its MC content is under 1.0% has little influence on that. The swelling of hydrogel is conformed to the second-order kinetics equation quite well under varying temperatures.

Experimental Study of the Oil-water Interfacial Tension of the Emulsion Base System

MENG Guoliang;ZHANG Fuyang;WU Guoqun;JIN Yong;XIE Kaiqiang;YANG Peng
Science & Technology Review. 2011, 29 (29): 44-46. ;  doi: 10.3981/j.issn.1000-7857.2011.29.006
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Abstract ( 352 )
Using contact angle tensiometer, measured the interfacial tension of oil-water two phase. The influence of temperature on surface tension of carbon fuel and emulsifier is investigated. Additionally, the effect of emulsifier on oil-water interfacial tension of emulsion base had been measured. The result indicate that, the surface tension of carbon fuel and emulsifier decrease as the temperature increases, interfacial tension of oil-water decrease significantly first as the emulsifier mass fraction increases, than the interfacial tension of oil-water be a constant value. Add different type emulsifier in emulsion base system, which use polymer emulsifier had relatively high value of interfacial tension. Results and findings have certain guiding significance, which for the formulation design and the safety production of emulsion explosives.

Preparation and Properties of Asymmetric Ceramic Membrane

LI Yuangao;ZENG Mengxiang;HONG Yubin;YAN Bin
Science & Technology Review. 2011, 29 (29): 47-51. ;  doi: 10.3981/j.issn.1000-7857.2011.29.007
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Abstract ( 409 )
Employing wet-chemical method, the Al2O3 powder was packaged with nano-material, through the low-temperature solid-state sintering method, large-size and high-performance asymmetric ceramic membranes were obtained, and the properties of 0.2μm asymmetric ceramic membrane were studied as well. It is demonstrated that the pore size distribution of the ceramic membrane is concentrated in the range of 0.1—0.2μm and its surface is in a perfect condition without any defects. The water flux of the ceramic membranes is stably above 3000L·m-2·h-1. The rejection of gibberellin is excellent. Burst pressure test shows that the membrane would break under the pressure of 7.5MPa. Moreover, the membrane would break under the pressure of 3.5MPa after soaking with the 20%wt sulfuric acid and 5%wt sodium hydroxide at 100℃ for 36h. All of above results indicate that the prepared asymmetric ceramic membrane in the work not only exhibits good performance under the working environment of less than 1.0MPa and pH value of 1—14, but also meets the requirements of most separation process under the extreme environment.

Simulation of Sewage COD Concentration Variation for Municipal Drainage Pipe Network

ZHENG Guohui;LUO Jianzhong;QIU Hongrong
Science & Technology Review. 2011, 29 (29): 52-55. ;  doi: 10.3981/j.issn.1000-7857.2011.29.008
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Abstract ( 382 )
In allusion to round crosssection concrete sewage pipe, the mathematical model of sewage COD was built based on the one-dimensional diffusing equation. And solution of the model was performed with the finite difference method and program of Visual Basic and Excel. The results show that the model predicts the variations of sewage COD concentrations in the process of sewage transmitting along the sewer well, and the maximum relative error between the simulated data and the measured data is only 2.5%. Taking the sewage pipe network of a town in Pearl River delta region for example, and further combining with mixed-node model, the variations of sewage COD concentration in municipal sewage system was also stimulated. The results show that all the parameters of the model are reasonably calculated and set and the model predicts the influent COD concentration of the sewage treatment plant quite well. The relative error between the simulated value and the measured value is 6.6%. Therefore, the model is able to make predictions and judgments on sewage COD concentration of the nodes, and is of benefit to the management of municipal sewage pipe network.

Volatile Organic Compounds Pollution in a Key Residential Area of Tianjin

NING Xiaoyu;LIU Bo;WANG Gen
Science & Technology Review. 2011, 29 (29): 56-60. ;  doi: 10.3981/j.issn.1000-7857.2011.29.009
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Abstract ( 397 )
The chemical speciation of Volatile Organic Compounds (VOCs) in the air of the Huayuan region, Tianjin is analyzed by using the GC-MS with pre-concentration of three-level cold trap. A total of 108 VOCs species are detected. The major components are alkanes and aromatics which account for 59.2% of VOCs. The average mass concentration range of VOCs in the winter and spring is 519.4—1029.6μg/m3, 299.8—463.8μg/m3, respectively. Among them, the acetone has the maximum concentration (20.0μg/m3); meanwhile the heptane has the minimum concentration (1.1μg/m3). The average mass concentration of VOCs and individual substances are higher in the winter than that in the spring. It could be explained by the seasonal variation of atmospheric degradation and dilution, while another important reason is that the surrounding pollutant sources due to atmospheric transport have an effect on Huayuan region.

Optimal Applications of Emergency Evacuation Time Model Based on Regression Analysis

DAI Wei;CHEN Jianhong;LI Zhijiang
Science & Technology Review. 2011, 29 (29): 61-64. ;  doi: 10.3981/j.issn.1000-7857.2011.29.010
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Abstract ( 401 )
In order to improve the prediction precision and application values of evacuation time model (briefly called an empirical model) that is generally accepted by the whole world, the influences of individual attributes (including both natural and social attributes) are analyzed. Based on regression analysis and the evacuation investigation on a large university gymnasium, a 185-set-data sample is established. Combined with the factors that affect evacuation behavior and time of individuals, the regression model of crowd evacuation time is built with the statistical software, SPSS 17.0. The individual attributes are consolidated into crowd attributes and the correction coefficient 'k' is solved on the premise of regression model. The empirical model is revised and examined through the utilization of correction coefficient 'k'. Finally, a fire evacuation design for a university stadium project is analyzed based on the optimized empirical model. The results indicate that with the use of regression analysis and correction coefficient 'k', the weakness of empirical model involving lack of consideration on the influences of crowd attributes could be effectively overcome, and both the prediction accuracy and application values of evacuation time model would be improved.

Influence of Seasonal and Vertical Distribution of Water Column Temperature on the Diel Vertical Migration of Daphnia hyaline in Qiandao Lake

XUE Junzeng;CAI Zhen;YAO Jianliang;WANG Baoqiang;YUAN Lin;WU Huixian
Science & Technology Review. 2011, 29 (29): 65-71. ;  doi: 10.3981/j.issn.1000-7857.2011.29.011
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Abstract ( 404 )
Qiandao Lake located in the upper reaches of Qiantang River is a large deepwater reservoir in north subtropical zone of China. In the lake, the water temperature reportedly has the vertical stratification phenomenon, and it presents thermocline in the summer. Cladocera is an important group in the reservoir ecosystem, it is generally recognized that Cladocera possesses the behaviors of vertical distribution and diel migration. Then the area next to the dam (with the total water depth exceed 60m) was selected as the sampling site, the environment factors and cladocerans species in vertical layers were analyzed in four seasons (from September 2004 to August 2005). The specie Daphnia hyaline was chosen as the main research object in order to clarify the influence of seasonal and vertical distribution of water column temperature on the vertical distribution pattern and diel migration of cladocerans in Qiandao Lake. The results show that D. hyaline is the dominate specie all year around, and essentially has an aggregated distribution pattern (MI>1) in water column, and with normal migration all year around except autumn. The thermocline in Qiandao Lake strengthens the aggregated distribution of D. hyaline in water column, promotes the upward-migration in the night. The fact makes the specie D. hyaline the important link between top and bottom waters for material interchange and energy flow.

Influence of Cigarette Smoking and Cold Dryness on Matrix Metalloproteinase and Airway Extracellular Matrix in Rat

LU Yong;LI Fengsen;JING Jing;WANG Jing;XU Dan;GAO Zhen
Science & Technology Review. 2011, 29 (29): 72-74. ;  doi: 10.3981/j.issn.1000-7857.2011.29.012
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Abstract ( 369 )
To establish the model by cigarette smoking and stimulus of cold and dryness environment, the Enzyme-linked immunoadsordent assay method was used to measure MMP-9 and TNF-α content in rat's blood serum and HA, LN in BALF, fluorescence quantitative PCR to determine the expression of MMP-1mRNA in bone. The results were analyzed by using SPSS 11.5 statistical software to see the effects of cigarette smoking and cold dryness in Xinjiang' environment on matrix metalloproteinase -9 (MMP-9) and tumor necrosis factor-α (TNF-α) in rat's serum, HA, LN in BALF , and MMP-1 mRNA in rat's bone. The results show that MMP-9 level is significantly higher than that in the control group (P<0.01), between the two groups, TNF-α in serum, HA, LN in BALF, are not significantly different, but the model group's figures are larger. The expression of MMP-1 mRNA is higher in the cold and dry group than in the control group (P<0.05). So it may be concluded that cigarette smoking and cold dryness environment can stimulate the increase of MMP-9 and TNF-α in rat's serum, HA, LN in BALF and MMP-1 mRNA in rat's bone. And this may be part of the mechanism that cigarette smoking and cold dryness environment lead to disorders of the body.
Reviews

Processing Procedure in the Laboratory and Quality Evaluation Method of Northern Style Chinese Steamed Bread

ZHOU Sumei;ZHANG Guozeng;ZHANG Meihong;ZHONG Kui;LIN Weijing
Science & Technology Review. 2011, 29 (29): 75-79. ;  doi: 10.3981/j.issn.1000-7857.2011.29.013
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Abstract ( 420 )
Chinese Steamed Bread (CSB) is a traditional staple food in the north part of China, which plays an important role in people's daily life. Besides the material characters, the preparation process of steamed bread also has important effects on the quality of CSB. The processing procedure and quality evaluation method of CSB, as well as the effects of preparation process on the CSB quality are reviewed, which could be of benefit to standardization of the processing procedure and quality evaluation method of CSB.
科技评论

Science & Technology Review. 2011, 29 (29): 80-80. ;  doi:
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Science & Technology Review. 2011, 29 (29): 81-81. ;  doi:
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Science & Technology Review. 2011, 29 (29): 82-82. ;  doi:
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主编心语

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

Science & Technology Review. 2011, 29 (29): 84-84. ;  doi:
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Science & Technology Review. 2011, 29 (29): 85-87. ;  doi:
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Science & Technology Review. 2011, 29 (29): 89-92. ;  doi:
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