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   Science & Technology Review
2011, Vol.29, No. 11-12
22 April 2011

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Reviews
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卷首语

Science & Technology Review. 2011, 29 (11-12): 3-3. ;  doi:
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Abstract ( 275 )
半月科技风云

Science & Technology Review. 2011, 29 (11-12): 7-7. ;  doi:
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Abstract ( 306 )
排行榜

Science & Technology Review. 2011, 29 (11-12): 8-8. ;  doi:
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Abstract ( 263 )
封面说明

Science & Technology Review. 2011, 29 (11-12): 8-8. ;  doi:
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Abstract ( 334 )
科技事件

Science & Technology Review. 2011, 29 (11-12): 9-9. ;  doi:
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Abstract ( 284 )
科技界声音

Science & Technology Review. 2011, 29 (11-12): 10-10. ;  doi:
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Abstract ( 267 )
科技工作大家谈

Science & Technology Review. 2011, 29 (11-12): 11-11. ;  doi:
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Abstract ( 311 )
科学共同体要闻

Science & Technology Review. 2011, 29 (11-12): 12-12. ;  doi:
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Abstract ( 282 )
科技期刊亮点

Science & Technology Review. 2011, 29 (11-12): 13-13. ;  doi:
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Abstract ( 257 )
科技要闻

Science & Technology Review. 2011, 29 (11-12): 14-14. ;  doi:
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Abstract ( 273 )
Exclusive

Social Computing Methods for Non-traditional Security Challenges Enabled by the Social Media in Cyberspace

Science & Technology Review. 2011, 29 (11-12): 15-22. ;  doi: 10.3981/j.issn.1000-7857.2011.12.001
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Abstract ( 399 )
Non-traditional security challenges enabled by the social media in cyberspace have imposed a major threat on the national security and societal stability. The evolution of the cyber space is analyzed with a particular focus on the issues related to security and stability. The changes in the government's positions towards the cyberspace and online virtual societies are also briefly discusses. Then the evolution of author own conceptualization and understanding of the cyberspace are reviewed from a security perspective since 2004, and the need for a scientific framework is analyzed to examine these security challenges. The fact that an ACP-based social computing approach provides an effective framework to address those non-traditional security issues is argued for.
Articles

Clone of TaCAT Genes in Wheat (Triticum aestivum L.) and Its Biochemical and Molecular Biological Characterization

Science & Technology Review. 2011, 29 (11-12): 23-31. ;  doi: 10.3981/j.issn.1000-7857.2011.12.002
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Abstract ( 1203 )
There is a close relationship between in vitro regeneration potential of wheat (Triticum aestivum L.) tissues and their resistant ability to oxidative stress. In order to dissect and provide theoretical evidences for subsequent experimental molecular functional characterization of TaCATs, e-PCR method and in silico techniques are employed for the isolation of the new member of wheat TaCAT family and the prediction on biochemical characters of TaCATs, respectively. TaCAT3, as a new member in wheat CAT gene family, is encoded a deduced 494-amino acid protein with the 1986bp and 1482bp of genomic DNA and cDNA, respectively, it shares 89% homology with CatA (Oryza sativa L.) and 81.1% identity with Cat3 (Zea mays L.), and is possibly targeted in the mitochondria according to the subcellular localization prediction. Furthermore, all the functional sites in TaCATs are highly conserved. Phylogenetic tree construction shows that the wheat TaCATs are able to form three separate branches with one isoform each. Swiss-PdbViewer 3.7 software package is employed for homology modeling of TaCATs after an appropriate template is acquired in Swiss Model online. The reconstructed model could well reflect the TaCAT senior structure.

The Structural Response of Beam String Structure in Case of Fire in Different Areas of a Large Space Building

Science & Technology Review. 2011, 29 (11-12): 32-36. ;  doi: 10.3981/j.issn.1000-7857.2011.12.003
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Abstract ( 1250 )
In this paper, the structural response of the Beam String Structure (BSS) in case of fire in a large space building is investigated by using the finite element method. The fires at the side segment, the middle segment and the full span of the BSS are considered separately in order to reveal the impact of fire areas on the structural response. The horizontal displacement of the right support block and the vertical displacement of the beam are obtained, together with the axial forces of the string and strut. The results indicate that the right support block of the BSS exposed to fire would move toward right with the increase of the fire temperature gradually in a notable extent. It is recommended that some measures should be taken to limit the maximum horizontal displacement of the right support block for improving the safety of the structure. The non-uniform temperature caused by different fire exposures may greatly influence the displacement, bending moment and axial force of the structure. This should be considered in the fire resistant design for this structure. A fire protection design for the BSS based on the assumption of its full span being exposed to fire is relatively conservative. The real fire condition should be considered during the fire resistant design and extra protecting measures should be taken for the weaker members and segments based on the analysis on the structure response of the BSS under some local fire condition.

Experimental and Numerical Simulation of Cavitating Flow Around a Disc

Science & Technology Review. 2011, 29 (11-12): 37-41. ;  doi: 10.3981/j.issn.1000-7857.2011.12.004
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Abstract ( 383 )
The unsteady cavitating flows around a disc are studied by experimental and numerical methods, where the Reynolds number remains the same and different cavitation numbers are obtained by changing the pressure values. Experiments are carried out in a rectangular test section of a cavitation tunnel; and a high-speed video camera is used to visualize the unsteady cavitation flow patterns. The calculations are conducted for a three-dimensional disc, based on a single-fluid model of the cavitation: the liquid/vapor mixture is considered as a homogeneous fluid with its composition being regulated by the mass transfer equation. A density modified corrected unsteady cavitation closure is used in calculations. The results show that the cavitation around the disc can be well simulated with the density modification based closure, the trend of cavity shapes against the cavitation number and the time is properly reflected. The flow field of the cavitating flows experiences several stages, including the small-scale bubble pulse, the instable bulk cavitation and the stable supercavitation. Here, the unsteadiness of the mass transfer process between the vapor and the two-phase regions is dominant.

Shift Schedule in the Auto with Dual Clutch Transmission Based on Cruise Gear Shift Program

Science & Technology Review. 2011, 29 (11-12): 42-47. ;  doi: 10.3891/j.issn.1000-7857.2011.12.005
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Abstract ( 1170 )
Shift schedule is the automatic shift based on the control parameters changes in the automatic transmission. It will affect the vehicle fuel economy, acceleration, and emission. It has approximately passed through three development phases so far: traditional type, experience-based type, and intelligent type. And according to the numbers of the control parameters, it can be roughly divided into three main categories: single parameter, two parameters, and three parameters schedule. On the basis of the available studies, a simulation model of a commercial sedan equipped with Dual Clutch Transmission(DCT) is developed via the AVL Cruise software, and two
parameters shift schedule which is widely used in the real auto engineering is taken account of. On this basis, the shift schedule is simulated and generated using the Gear Shift Program(GSP) module of the AVL Cruise software. Furthermore, the transmission states is
optimized with the considerations involving vehicle fuel economy, emission, road slope, and driving environment under the given cycle condition. The result shows that this method could generate the shift schedule accurately and quickly and optimize the transmission states on the specific cycle conveniently. These works could be used in the effective calibration of automatic transmission and shorten the vehicle development cycle.

Integrated Information System for Urban Underground Pipelines Based on GIS

Science & Technology Review. 2011, 29 (11-12): 48-52. ;  doi: 10.3981/j.issn.1000-7857.2011.12.006
Full text: HTML (0 KB)  PDF  (1741 KB)  ( 239 )
Abstract ( 528 )
The urban underground pipeline information system is based on the technology of GIS, considering the pipeline characteristics with respect to the data complexity and hiding. The application framework is built on COMGIS, and the advantage of the information system for the urban underground pipelines based on ArcEngine is analyzed. The integration technology of GIS is used for the operating procedure in the data integration, information collection, information disposal and spatial analysis. The integration technology of Visual C# 2005 and ArcEngine is combined with the database of Oracle 9i database by applying ArcSDE. The system provides the function of spatial information extracting, processing, management, inquiry and statistical analysis, for professional information and spatial information with respect to underground pipelines, and for accurate positioning and dynamic management of underground pipeline data.

The Physical and Mental Stress Symptoms Effect of Population with Different Affect After the Earthquake

Science & Technology Review. 2011, 29 (11-12): 53-57. ;  doi: 10.3981/j.issn.1000-7857.2011.12.007
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Abstract ( 395 )
While facing the huge earthquake, the physical and psychological assistance for victims is deemed necessary. Exploring the physical and psychological symptoms for different types of victims is beneficial to reduce the impact of disasters and improve the effect of the assistance. The physical and psychological stress symptoms are characterized by four indicators based on the prior related literature, namely, physical symptoms, cognitive symptoms, emotional symptoms, and behavioral symptoms. The catastrophe progression method is applied to build a physical and psychological stress symptoms catastrophe model for the earthquake victims and "5.12" Wenchuan earthquake is used as an example for the empirical research. According to demographic characteristics, the victims of Wenchuan earthquake are categorized by gender, age, and extent of earthquake impact. The impact of the earthquake on different types of victims is analyzed and it is found that the biggest impact is on the earthquake victims of female, the middle-and-old age, and people in worst-hit region. Facing with the same disaster, the same type of people exhibits different physical symptoms, cognitive symptoms, emotional symptoms, and behavioral symptoms. The catastrophe progression method for the physical and psychological stress symptoms model is adopted to analyze the physical and mental stress symptoms of earthquake victims, its results are in consistent with previous related research conclusion. It is indicated that the model is reliable and effective for such problems, thus the model provides a new method for the post-disaster relief work.

Improvement of RED Algorithm in the Embedded Network Communication

Science & Technology Review. 2011, 29 (11-12): 58-61. ;  doi: 10.3981/j.issn.1000-7857.2011.12.008
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Abstract ( 1155 )
The RED algorithm is used to solve the network congestion problem. In the embedded network communication, the drop packet ratio is proportional to the average queue length, and,as a result, the drop packet ratio is high when the network congestion is not serious and the drop packet ratio is low when the network congestion is serious, so the congestion control is not effective. The density function IMPRED (Improved Random Early Detection) can solve that problem. In the IMPRED algorithm, there are two curves, one is 3 times density function, the other is 1/3 times density function. With the IMPRED algorithm, the drop packet ratio is smaller around the minimum threshold, and larger around the maximum threshold, to avoid the global synchronization of the network. Using the time complexity and space complexity of the algorithm to compare the RED algorithm and the IMPRED algorithm, it is found that the time complexity of IMPRED and RED is O(n), the space complexity of IMPRED is as large as the RED's. The NS 2.30 simulation results show that when the
network congestion does not appear, the efficiency of IMPRED algorithm and RED algorithm is the same. When the network is congested, IMPRED algorithm can improve the network throughput and reduce the delay jitter, making the network more stable.

Analysis of Three-dimensional Simulation for Steel Sheet-pile Cofferdam in Deepwater Foundation

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Science & Technology Review. 2011, 29 (11-12): 62-66. ;  doi: 10.3981/j.issn.1000-7857.2011.12.009
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Abstract ( 399 )
Based on the deepwater geological and hydrological conditions, and the soil parameters, a steel sheet pile cofferdam FSP IV supporting method of the closed button Larsen type is developed. According to the actual stress conditions of the steel sheet pile, the Midas-Civil software is used to establish the three-dimensional structure of the double-wall steel cofferdam in space and the three-dimensional simulation is carried out for the overall model to check the analysis. According to different stages of steel sheet pile construction, 6 kinds of load conditions are selected in the calculation, and three most adverse conditions are analyzed with respect to structural deformation, the moments in steel sheet pile, and the brace forces, through numerical simulations and the monitoring of displacement in the construction process, to better predict the trends of the supporting structure and to meet the needs of construction, in view of saving investment, shortening the construction period, and improving social and economic benefits.

Numerical Simulation of Distribution of Spontaneous Combustion "Three-Zone" Division in Fully Mechanized Goaf Under Complicated Situation

Science & Technology Review. 2011, 29 (11-12): 67-70. ;  doi: 10.3981/j.issn.1000-7857.2011.12.010
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Abstract ( 430 )
Under the influence of the complicated geological conditions, the method of sampling analysis by pipe for dividing "three-zone" in the goaf has many limitations. Utilizing the method of numerical simulation to analyze "three-zone" in the goaf becomes the main means. The fluid mechanics calculation software, Fluent is applied to simulate the air leakage flow field status in the goaf of 1121(3) working face of Panbei Mine, Huainan Mining Group, and then the "three-zone" of goaf location and area are obtained according to the air leakage flow field simulation result. The results show that the width of "oxidation-zone" is about 40 meters. Considering the coal spontaneous combustion stage is three to six months, it is impossible that the residual coal in the goaf is spontaneously combusted during a working face mining process. At last, the different air leakage flow field status in the goaf is obtained under the condition of different ventilation quantity. It is found that the more ventilation quantity is provided, farther away from the working face the location of
"oxidation-zone" is and the wider extent of "oxidation-zone" is.
Reviews

Preparation and Development of TiO2 Nanotubes Application in Gas Sensors

Science & Technology Review. 2011, 29 (11-12): 71-74. ;  doi: 10.3981/j.issn.1000-7857.2011.12.011
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Abstract ( 678 )
TiO2 is widely used in the production of gas-sensor, solar cell and potocatalytic degradation, due to its good stability, non-poisonous nature and strong sensitivity to gas and wettability. TiO2 nanotubes are typical one-dimensional nanomaterials with relatively extensive chemical and physical properties. As the production cost is low, it has a wide application prospect. In particular, recent studies suggest that compared with other forms of nano-materials, it has a larger specific surface area, stronger adsorbability and good nanometer size effects. TiO2 nanotubes have a great potential in fields of photocatalysis, sensors, solar cells and others and have attracted much research interest. Although the production of TiO2 is a mature technology, its application in the field of gas-sensors remains an issue to explore. The preparation of TiO2 nanotubes is the important prerequisite for its application in various fields, so main preparation methods of TiO2 nanotubes firstly are discussed in this paper to understand the shape and general components of TiO2 nanotubes. The application of TiO2 nanotubes in gas sensors is specifically addressed among its many applications.

Advances in Peak Shaving Technology of Gas Pipeline System

Science & Technology Review. 2011, 29 (11-12): 75-79. ;  doi: 10.3981/j.issn.1000-7857.2011.12.012
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Abstract ( 473 )
Four abroad research directions of peak shaving problems involving gas pipeline system are summarized, they include the measures of peak shaving, how to set up the withdrawal schedules of underground gas storage, how to apply the steady model to analyze middle or long-term peak shaving problems, and the simulation of short-term peak shaving problems. Several main peak shaving measures in the production are introduced. Three short-term peak shaving scenarios are proposed based on research achievements at home and abroad and the operators' experience. The optimization of peak shaving scenarios is discussed and a multi-objective optimization guideline for short-term peak shaving scenarios is proposed. The characteristics of some popular gas pipeline simulation software, such as TGNET, SPS, and SIMONE, are introduced. The current difficulties in the short-term peak shaving optimization are reviewed, these difficulties include how to set up a sensible multi-objective optimization guideline, how to deal with the fuzzy factors in the multi-objective optimization guideline and pursue an effective algorithm to solve the multi-objective fuzzy optimization.
书评

Science & Technology Review. 2011, 29 (11-12): 80-80. ;  doi:
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Abstract ( 292 )
科技纵横捭阖

Science & Technology Review. 2011, 29 (11-12): 81-81. ;  doi:
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Abstract ( 273 )
读者之声

Science & Technology Review. 2011, 29 (11-12): 82-82. ;  doi:
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Abstract ( 310 )
主编心语

Science & Technology Review. 2011, 29 (11-12): 83-83. ;  doi:
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Abstract ( 288 )
智力休闲

Science & Technology Review. 2011, 29 (11-12): 85-85. ;  doi:
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Abstract ( 274 )
走向职场

Science & Technology Review. 2011, 29 (11-12): 86-86. ;  doi:
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Abstract ( 315 )
科技人才招聘

Science & Technology Review. 2011, 29 (11-12): 87-89. ;  doi:
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Abstract ( 292 )
全球招聘新闻

Science & Technology Review. 2011, 29 (11-12): 90-93. ;  doi:
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Abstract ( 272 )

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