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   Science & Technology Review
2012, Vol.30, No. 28-29
08 October 2012

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Science & Technology Review. 2012, 30 (28-29): 3-3. ;  doi:
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科技风云

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封面图片说明

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特别栏目

Science & Technology Review. 2012, 30 (28-29): 8-8. ;  doi:
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科技事件

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科技工作大家谈

Science & Technology Review. 2012, 30 (28-29): 11-11. ;  doi:
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Exclusive

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Articles

Blade Simulation of Small H-Vertical Axis Wind Turbine Based on Optimal Wind Power Coefficient

GUO Xingwen;LIU Yingbo;QIU Yong
Science & Technology Review. 2012, 30 (28-29): 20-23. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.001
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Abstract ( 323 )
A two-dimensional CFD model of the external flow-field for a 1kW H-vertical axis wind turbine is established by using the software of Flunent. The sliding mesh technique and the SST k-ω turbulent model are adopted. The model is intended to study the impact of different lengths of chord and different shapes of airfoil on the wind power coefficient for the H-vertical axis wind turbine. By fixing the Gurney flap of different heights on the tail of blade, the efficiency improvement of wind power coefficient is studied, and the curve of wind power coefficient for the H-vertical axis wind turbine with the tip-speed under different situations is derived. The results show that the blade of NACA 0018 with the chord length of 300mm is relatively suitable for an H-vertical axis wind turbine. The H-vertical axis wind turbine works more effectively at a tip-speed ratio from 2.5 to 3.5. The wind power coefficient of H-vertical axis wind turbine is able to be increased 3% by using the Gurney flap with flap height equaled to 1% of chord length and tip-speed ratio of 2.8.

Probability Safety Analysis of Improvement Design of ASG System

SHAO Ge;TONG Lili;CAO Xuewu;XUE Junfeng;WU Qifang;WANG Yong;YAN Yingdi
Science & Technology Review. 2012, 30 (28-29): 24-28. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.002
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Abstract ( 492 )
The principal role of the Auxiliary Feedwater System(ASG) is to support the removal of stored and decayed heat from the Reactor Coolant System (RCS). After the Three Mile Island (TMI) accident, the ASG modification for the mitigation of the accidents of the nuclear power plants (NPPs) becomes a research issue. In order to improve the overall safety of nuclear power plants (NPP) and the system reliability, the ASG is renovated with the improved safety facility (ESF) for the Fuqing NPP. A fault tree (FT) model of the ASG before/after the improvement is built by the Probabilistic Safety Analysis (PSA) to analyze the system reliability. The β factor model is used to quantitatively analyze the failures of the components and the minimal cutsets of the FT are calculated. The results show that the probability of the ASGP0200 and the ASGP0300 as the top key event is significantly reduced; and the percentage of the turbine driven pump minimal cutset probability in the top key event probability is also significantly reduced. The initial event tree (ET) model related to the ASG before/after the improvement is built to analyze the contribution of the improvement on the CDF under the power operation condition. The percentage of the initial event contribution on the CDF before/after the ASG improvement is also investigated. The results show that because of the ASG design improvements, the CDF of the NPP is decreased, which means that the safety of the NPP is improved.

Low Cycle Fatigue Behavior of Zr-4 Cladding Before and After Neutron Irradiation

ZHANG Haisheng;LI Guoyun;HUANG Juan;JIANG Guofu;LI Furong;WANG Fei
Science & Technology Review. 2012, 30 (28-29): 29-32. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.003
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The low cycle fatigue property of the Zr-4 cladding before and after the neutron irradiation is investigated in this paper. The stress-strain curve and the Coffin-Manson relation of the pre-irradiation specimens are first obtained. Then an estimation of the effect of the neutron irradiation on the low cycle fatigue property of Zr-4 cladding is obtained. The fatigue crack microstructure is analyzed and the mechanism of the fatigue is discussed. It is shown that the Zr-4 tube sees a serious irradiation-embrittlement. Both non-irradiated and irradiated specimens show cyclic softening. The strength coefficient and the hardening exponential are increased, the material constant is decreased and the life of the Zr-4 tube is reduced after the iradiation.

A New Production Calculation Model for Vertical Fractured Well in the Low Permeable Reservoir

TIAN Leng;CHANG Tielong;ZHENG Rongchen;ZHANG Jie
Science & Technology Review. 2012, 30 (28-29): 33-37. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.004
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Abstract ( 509 )
Currently, conventional reservoir engineering methods for dynamic analysis and low permeable reservoir performance forecast are often inaccurate, especially they are not suitable for oil well productivity forecast. Aiming at this problem, taking threshold pressure gradient, reservoir stress-sensitivity, micro-compressibility of Newton fluid, and pressure dependent viscosity into consideration, a nonlinear radial stable flow model for low permeable reservoir has been built by using the complex function theory; an analytical solution method is adopted for the solution. Combining with the concrete parameters collected from the certain well area in Changqing low permeable oilfield, all parameters' sensitivity on production performance in the productivity equation have been analyzed and the deliverability curves with different parameters have also been drawn. At last, the superiority, adaptability, and feasibility for evaluating productivity and forecasting oil productivity of the model are also discussed in comparison with a linear flow model. As a result, low permeable reservoir should be developed with a short pattern system due to its low permeability and low pressure transmitting speed. When formation pressure drops rapidly, advanced water injection should be adopted to remain formation pressure.

Seepage Flow Theory and Application of New Production-decline Model After Water Breakthrough and Its Applications

YANG Renfeng;YANG Baoquan;PI Jian;YANG Li
Science & Technology Review. 2012, 30 (28-29): 38-41. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.005
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Abstract ( 357 )
Currently, the oil production decline after water breakthrough is lack of theoretical research, and the production decline forecasting methods need to be improved. Based on the percolation theory of relative permeability curve and material balance equation, the new model for oil production decline is derived. The research shows that with the oil saturation is getting lower and lower, the relative permeability of oil phase is getting weaker and weaker, and the relative permeability of water phase is getting stronger and stronger. The production decline law is determined by the relative permeability curve expression; three common production decline models could be derived by ignoring the ratio of oil water viscosity ratio to the relative permeability of water phase from the new model. The new model is a more uniform production decline equation, giving consideration to several factors. The research has a certain reference value for deeply understanding the production decline and for increasing forecast accuracy.

Waterflooding Evolution Rule of PI 1-2 Oil Layer in the Lamadian Oil Field

NIE Chunlin;MA Shizhong
Science & Technology Review. 2012, 30 (28-29): 42-46. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.006
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Abstract ( 342 )
The Daqing Lamadian oil field has developed by basic well pattern, layer system adjustment pattern, producer injector adjustment pattern, secondary infilled well pattern, thick oil layer polymer flooding pattern, and polymer flooding upward pattern. Up to 2010, the PI1-2 layer has completely shifted to polymer waterflood in Daqing Lamadian oil field. With oil field developing, the oil layer waterflooding thickness and hierarchy increase. The water flooding situation becomes more and more complex. Through the analysis on coring well data change of property, water washing combining well logging curve characteristics and waterflooding explanation in different development stages, the evolution rules of lithologic character, petrophysical property, electrical property, and oil-bearing property are summed up in the process of water flooded reservoir. Based on the above results, thick oil reservoir water flooding regularity is summed up. The distribution of low waterflooding (washing) thickness is determined. It lays the foundation for further discovering potentials of PI1-2 oil layer; the anatomy of waterflooding main controlling factors provides the guidance for polymer flooding development in the sub-main layers.

Gray Catastrophe of Asphalt Aging Behavior

LIU Shengjie
Science & Technology Review. 2012, 30 (28-29): 47-50. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.007
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Abstract ( 443 )
The changes due to evaporation, oxidation, and polymerization in the internal structure of asphalt and other reactions could change the nature of asphalt and the performance of asphalt mixture, and have influence on the life and durability of the pavement during the storage, transport, mixing, construction, and long-term use of asphalt. In order to study the influences of aging on asphalt performance, the regulation of material physics property change was analyzed. The RTFOT experiment was applied to study on the performance attenuation of 90# asphalt based on the indexes of penetration, ductility, softening point, and viscosity. According to the principle of evaluating system stability with the variable tendency of its compatibility, the catastrophic potential function between asphalt performance and aging time was built based on the test data, and then the destabilization of asphalt aging was predicted by the grey-cusp-catastrophic destabilization prediction model. The research results are shown as follows: the catastrophe of asphalt exits in the aging process; and hysteresis phenomenon exits between catastrophe and aging actions. It is indicated that the catastrophe theory on the asphalt aging is feasible, and is able to predict the rule of asphalt aging more accurately. In order to make the asphalt pavement have the longer services life, the measures should be taken to extend the occurring time of catastrophe.

Shock Resistance Characteristics of Diesel Engine Fixed Assembly with Bolt Connection

ZHAO Jianhua;SUN Yupeng;LIU Zhen;ZOU Kaifeng
Science & Technology Review. 2012, 30 (28-29): 51-55. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.008
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Abstract ( 361 )
The bolt connection is one of the most common connection methods applied in a diesel engine. It will affect the dynamic characteristics of the diesel engine's structure.A test model of the machine foot bolt connection is prepared to study the shock resistant characteristics of the bolt connection in the diesel engine. The screw-thread connection model of the beam - spring unit is introduced into the experiment to build the finite element model. A difference less than 5.4% is shown by comparing the results of the test model and the finite element analysis, which has verified the feasibility of the modeling method. With the DDAM (Dynamic Design Analysis Method), the impact safety of all components is verified by analyzing the shock response of the diesel engine's fastened components and phase-coupling the shock stress' response results in three directions. The experiments show that the material of the diesel engine feet should be replaced by one with a higher yield limit, while the machine foot bolts satisfy the national military standard requirements. The bolt connection model is shown to provide realistic results in the diesel engine shock resistance study.

Synchronization of the Multi-axis Servo Motion Controller System Based on the EtherCAT

ZHOU Yantao;ZHANG Shun;HUANG Qing;ZHOU Yaming
Science & Technology Review. 2012, 30 (28-29): 56-60. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.009
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Abstract ( 611 )
The multi-axis servo linkage sees more and more applications in the industrial field, and its synchronization is an urgent issue. The introduction of the EtherCAT (Ethernet for Control Automation Technology) into the multi-axis servo motion system could improve the synchronization of the system. In order to enhance the performance of a multi-axis servo motion system with the EtherCAT, this paper first discusses the EtherCAT's basic communication theory, and the basic structure of a multi-axis servo motion controller system, based on the EtherCAT, and the theory of the slave. Then, we analyze the synchronization of the EtherCAT by calculating the delay, the compensating offset and the compensating drift. At last, an experiment is carried out, which shows that, the EtherCAT's synchronization can satisfy the requirements of the multi-axis motion controller system very well.

Design of a Wideband Low Noise Amplifier with a Differential Signal Transformation Circuit

ZHAO Jixiang;YUAN Shengjie;LI Yunfeng
Science & Technology Review. 2012, 30 (28-29): 61-64. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.010
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Abstract ( 354 )
The design of an improved CMOS wideband Low Noise Amplifier (LNA) is presented. The bandwidth range is between 1 —5GHz, and the LNA is able to be used in the devices for cellular communication system and wireless local area network. The LNA comprises two stages. The first stage circuit is able to transform the signal received from the antenna or fitter into differential signals. It is able to reduce the number of discrete components of receiver system by integrating the conversion circuit into the LNA. The second stage contains common-source and common-gate MOS transistors. This stage provides an enough power gain and a good output matching for signals. The performance of power gain becomes better by adding a matching inductance between two transistors of second stage circuit. The improved CMOS LNA is designed and simulated with TSMC 0.18μm technology by using ADS software. Results illustrate that the noise figure of the LNA is below 2.3dB in the range of 1—5GHz, the gain for entire bandwidth is 14dB and the scattering parameters of S11 and S22 are all less than -10dB, having good input and output matches of the low noise amplifier.

Effects of Flos Puerariae and Seeds of Hovenia Dulcis Thunb and Compatibility Groups Extracted by Water and Alcohol on Experimental Alcoholic Liver Disease of Rats

LIU Haiyan;ZHONG Gansheng;WANG Xi;LI Yiwen;LIU Jia;CHEN Shaohong;OU Lina
Science & Technology Review. 2012, 30 (28-29): 65-70. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.011
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Abstract ( 388 )
In order to observe the antioxidant effect of different proportions of flos puerariae lobatae and hoveniae semoveniae semen extracted by alcohol and water, at the same time to determine whether different methods of extraction will have different effects and which method is better, alcoholism rat models were induced by administrating wine and Wistar rats were randomly divided into the normal group, the model group, the positive group, the flos puerariae group, the group of seeds of hovenia dulcis Thunb, and the groups of different ratios of compatibility. All rats were killed and their livers and blood were taken to examine the serum alanine aminotransferase (ALT), the serum aspartate aminotransferase (AST) and the Alkaline Phosphatase Kit (ALP). It is shown that the model test is successful and each treatment group sees a certain improvement of the liver function, and the water extraction on the whole is better than the alcohol extract as far as the effect is concerned. It is suggested that the heavy drinking can cause liver damage, the Gehua with the seeds of hovenia different proportion on the alcoholic liver injury in the rat liver has a protective effect, and the traditional water extraction of the drug application used in the experiment is better than the alcohol one.

Preparation of a New Porous Titanium Implant

CUI Xiaoming;CHEN Liangjian;ZHENG Yao
Science & Technology Review. 2012, 30 (28-29): 71-75. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.012
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Abstract ( 462 )
This paper discusses the preparation of new porous titanium implants with different porosities and the influence of osteoblast cells on adhesion, proliferation, differentiation and osseointegration. The metal injection molding (MIM) is used to prepare the porous titanium implants with porosities of 30%, 40%, 50%, 60%, followed by the surface modification by means of acid-base heat treatment, and biomimetic deposition hydroxyapatite. With four groups of materials cultured with MG63, the influences of different porosities of the porous titanium implant on the adhesion, the proliferation and the differentiation of osteoblast cells MG63 in vitro are studied. With the four groups of materials implanted to the femoral of dogs for 12 weeks, the hard tissue slice and dye are made by using the Goldner's three color method, to study the effect of osseointegration. The results show that the 60% of cases of a group of materials are better than the other three groups on four aspects: the osteoblast quantity, the osteoblast stick form, the content of ALP and OCN and the formation of the bony combination. It is indicated that the high porosity implants after the surface modification with connected holes are propitious to the osteoblast cell's adhesion, the proliferation and the differentiation. They are also propitious to the osseointegration. This study provides a theoretical basis for the development of new porous titanium implants and implant dentures.

Removal Effect for Ammonia-Nitrogen and COD in Coking Wastewater by Using Six Kinds of Aquatic Plants

WANG Kai;LI Xia;CAI Jin;FENG Jia;XIE Shulian
Science & Technology Review. 2012, 30 (28-29): 76-81. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.013
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Abstract ( 502 )
In order to study the purification effect of aquatic plants in the treatment of the coking wastewater, Chara sp., Nasturium officinale, Cladophora sp., Potamogeton crispus, Polygonum orientale, and Phragmites australis were, respectively, used to remove ammonia-nitrogen and COD from the coking wastewater, with the Nessler's reagent colorimetric methods and the dichromate potassium methods. The results indicate that these six kinds of aquatic plants have high removal effects for ammonia-nitrogen and COD. Their removal effects of ammonia-nitrogen and COD reach a saturation state after treating for 5 to 7 days. Then, the removal effects do not increase significantly (P > 0.05) with extending the treatment time. The best removal efficiency for the ammonia-nitrogen in the coking wastewater by using Chara sp., Nasturium officinale, Cladophora sp., Potamogeton crispus, Polygonum orientale, and Phragmites australis is 20.38%, 19.37%, 23.61%, 22.59%, 21.77%, and 32.4%, respectively. The best removal efficiency for the COD in the coking wastewater by using Chara sp., Nasturium officinale, Cladophora sp., Potamogeton crispus, Polygonum orientale, and Phragmites australis is 27.51%, 27.13%, 18.63%, 17.03%, 25.72%, and 69.04%, respectively. Compared with the other 5 kinds of plants, Phragmites australis has the highest (P < 0.05) removal effect for ammonia-nitrogen and COD.

Determining the Amount of Permissible Organic Compound Fertilization for the Purple Soil Based on the Physiological-biochemical Characteristics of Maize Seedlings

ZHAO Li;;HE Yuxiao;PENG Hui;LIU Gangcai
Science & Technology Review. 2012, 30 (28-29): 82-88. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.014
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Abstract ( 375 )
The tolerable amount of organic compound fertilization for the corn on purple soil is determined by studying the physiological and biochemical features of maize based on the principle of chlorophyll fluorescence kinetics and photosynthesis. The physiological and biochemical indexes include plant height, leaf area, photosynthetic rate, and chlorophyll fluorescence of leaf. Results show that the plant height, leaf area index, stomata conductance, net photosynthetic rate, intercellular CO2 concentration, transpiration rate, and maximum PSII photochemical quantum yield (Fv/Fm) are increased with the increase of the amount of fertilization. It is found that the fertilization amount ranged from 0.75 t/hm2 to 1.49t/hm2 (N-P2O5-K2O=0.128-0.128-0.128—0.253-0.235-0.235t/hm2) is able to make a large leaf area, good growth performance, photosynthetic rate, and relatively high yield of corn and also make maize growing in the course of nature to maintain its normal photosynthesis. Therefore, the fertilization amount ranged from 0.75 t/hm2 to 1.49t/hm2 (N-P2O5-K2O=0.128-0.128-0.128—0.253-0.235-0.235t/hm2)is the tolerable fertilization amount.

Chemical Weathering Processes and Its Atmospherical CO2 Consumption of the Bainihe Watershed in Wujiang River Source Drainage Basins Area

JIAO Shulin;LIANG Hong;DING Rong
Science & Technology Review. 2012, 30 (28-29): 89-93. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.015
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Abstract ( 463 )
For understanding the law on the atmospherical CO2 consumption effect due to Dissolved Inorganic Carbon (DIC) discharged from the chemical weathering processes in the Source Drainage Basins Area of the Karst region, a riverine hydro-chemical investigation is carried out during the entire hydrologic year from June 2010 to May 2011 in the water channel of the Xiangyang Hydrological Stations located at the Bainihe watershed in Wujiang River Source Drainage Basins Area, that the cover layer is mainly carbonate as well as Karst landforms are widely developed. The variation of the Total Dissolved Substances (TDS), its sink flux to atmospherical carbon, and intensity change in the cross-section studied are analyzed. Result indicates that the annual fluxes on the TDS are amount of 6.37×1010g with 7.495×107g·km-2·a-1 in chemical weathering modulus, and the annual fluxes of the DIC are amount of 5.483×108mol with 6.45×105mol·km-2·a-1 in DIC weathering modulus. Based on the carbonate weathering contribution rate amounting to 98% of the riverine DIC, the annual fluxes of the atmospherical CO2 consumption at Xiangyang Hydrological Stations of the Bainihe watershed are about 2.819×108mol with 3.32×105mol·km-2·a-1in modulus, about 95% of which are discharged during the hot-rainy period from June to November in the year surveyed. Impacted strongly by Karst process, the chemical weathering and its carbon consumption are closely related to the characteristics of watershed land surface, climatic condition, as well as hydrological processes in the Bainihe watershed.

Information Platform for Enterprise Accounting

WEI Yanling
Science & Technology Review. 2012, 30 (28-29): 94-97. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.016
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Abstract ( 356 )
Aiming at the existing issues on the practical process of enterprise accounting information platform involves a high investment, and suffers a low efficiency and a low software quality. Through an analysis of the construction and the realization of the existing enterprise accounting information system, on enterprise accounting information platform for the background and the significance to carry on the thorough analysis, a new enterprise accounting information platform system is designed, to the enterprise accounting information platform construction of relevant hardware and software environments. in detail, for the development of enterprise accounting information platform of testing. The test results show that the system performs well, and can achieve the expected goal. The research of accounting information to help enterprises enhanced efficiency, enhanced the competitiveness of enterprises is of great practical significance.

Role of Science Communication in Social Education: A Case Study of the Impact of a Science Communication Event on Education

ZHANG Zhimin;REN Fujun
Science & Technology Review. 2012, 30 (28-29): 98-102. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.017
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Abstract ( 350 )
The social education is playing a more and more important role in the context of building a lifelong learning society. A science communication event is a kind of social education resource and it improves the citizen's scientific literacy. In order to explore the role of science communication events in the social education and related assessing methods, a science communication event is studied, which concerns with water saving and protecting. This event is held in a science and technology museum and is open to general public. In a questionnaire survey, 1000 valid questionnaires were returned. Based on the analysis of data from the questionnaires, the science communication event is found to have a positive educational impact on its visitors. First, it improves the visitor's awareness of knowledge about saving and protecting water. Second, it helps the visitors to develop an attitude of "saving and protecting water is everybody's social responsibility and one should take part in that move actively" .Third, it is likely to guide visitors to save and protect water in their everyday life. It is indicated that as a social public educational resource, the science communication event is beneficial to public's lifelong learning, better understanding of science, technology and society and to the building of students' knowledge structure. Some suggestions are made. First, the school science education should make more use of science communication events. Second, it is necessary to broaden the target groups and to benefit more people. Third, the science communication event should be designed effectively according the public' need, interest and learning habit.
Reviews

Developments of Laser Plasma Propulsion Technology

ZHENG Zhiyuan;GAO Hua;FANG Zhenjun;XING Jie;DONG Aiguo;WU Xiuwen;ZHANG Zili
Science & Technology Review. 2012, 30 (28-29): 103-107. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.018
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Abstract ( 395 )
The laser plasma propulsion is a most prospective propulsion technology due to its unique advantages such as the high specific impulse, the large range of momentum thrust and the easily realized digital control. A review of the laser source, the theoretical model and the target material is made in this paper, including the progress of the laser plasma propulsion. For the laser source, the nanosecond and the microsecond laser pulses should be used together for their complementation nature. A two-dimensional model should be urgently developed, especially in a confined laser plasma propulsion. For the target material, the liquid as one of optimum target materials attracts much attention due to its higher coupling coefficient. To solve the problem of the low specific impulse due to the splashing behavior, the target properties, in particular, the viscosity are analyzed and a comparison is made among the target materials. A new energy-containing liquid material is discussed. Moreover, the parameter measurements of the coupling coefficient and the specific impulse are discussed. A new double probe beam device is introduced to measure the target momentum. Its measurement results are independent of the probe beam diameter and the target thickness.

Application and Prospect of Harmonic Suppression Technology in Oilfield Electric Distribution System

WANG Jun
Science & Technology Review. 2012, 30 (28-29): 108-111. ;  doi: 10.3981/j.issn.1000-7857.2012.2829.019
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Abstract ( 291 )
With the wide application of the power electronic equipment in the oilfield electric distribution network, the waveform distortion of the grid becomes increasingly serious and damaging to the normal operation of the electrical equipment and the power system reliability. Based on the characteristics of the oilfield electric distribution network and the basic theory of the harmonic analysis, this paper gives a brief introduction to the causes and damages of harmonic waves in the oilfield electric distribution system, the harmonic control method and the filtering techniques are compared, and the development process of the Harmonic Dynamic Suppression technology using the active filter in the oilfield electric distribution system is discussed. Finally, the prospect of the development of the Harmonic Dynamic Suppression in the oilfield electric distribution system is commented.
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