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   Science & Technology Review
2011, Vol.29, No. 16
08 June 2011

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卷首语

Science & Technology Review. 2011, 29 (16): 3-3. ;  doi:
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科技风云

Science & Technology Review. 2011, 29 (16): 7-7. ;  doi:
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封面图片说明

Science & Technology Review. 2011, 29 (16): 8-8. ;  doi:
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特别栏目

Science & Technology Review. 2011, 29 (16): 8-8. ;  doi:
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Science & Technology Review. 2011, 29 (16): 10-10. ;  doi:
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Science & Technology Review. 2011, 29 (16): 12-12. ;  doi:
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Science & Technology Review. 2011, 29 (16): 13-13. ;  doi:
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Science & Technology Review. 2011, 29 (16): 14-14. ;  doi:
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Science & Technology Review. 2011, 29 (16): 83-83. ;  doi:
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Science & Technology Review. 2011, 29 (16): 84-84. ;  doi:
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Science & Technology Review. 2011, 29 (16): 85-85. ;  doi:
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Science & Technology Review. 2011, 29 (16): 94-94. ;  doi:
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科技事件

Science & Technology Review. 2011, 29 (16): 9-9. ;  doi:
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科技工作大家谈

Science & Technology Review. 2011, 29 (16): 11-11. ;  doi:
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Exclusive

Science & Technology Review. 2011, 29 (16): 15-24. ;  doi:
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Articles

Numerical Analysis of Interaction of SO2 Emission Among 19 Cities Along the Middle-up Stream of Yellow River and Their Contribution to Beijing City

WANG Fanqiang;XU Dahai;SHI Jingang;CHEN Xiaoli
Science & Technology Review. 2011, 29 (16): 25-29. ;  doi: 10.3981/j.issn.1000-7857.2011.16.001
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Abstract ( 409 )
Based on the SO2 emission inventory and meteorological data along the middle-up stream of Yellow River in 2007, the simulation system including CALPUFF and MM5 models is utilized to simulate, predict and analyze the interaction of SO2 emission between one city and other 18 cities, and the contribution of their transport to Beijing city. From the results, the following conclusions can be reached. (1) It is obvious that the SO2 emission dramatically interacts with that around the circumjacent cities, in the second level (0.06mg/m3) of National Standard of SO2 emission, 49.8% and 44.3% of average yearly SO2 concentration in Yinchuan and Xianyang cities are contributed by that around the circumjacent cities, respectively. (2) The city whose contribution to neighboring city exceeds 10% of the second level includes Shizuishan to Yinchuan, Wuzhong to Yinchuan, Weinan to Xiangyang, Weinan to Tongchuan, and Xiangyang to Weinan. (3) The long distance transport of SO2 emission from adjacent cities influences to some extent the concentration of SO2 in Beijing city, the contribution of average yearly SO2 concentration to Beijing reaches 0.00038mg/m3 with the largest in Ordos,followed by Baotou, 0.00032mg/m3, and is only 0.00001mg/m3, the smallest for Baoji and Xinzhou and Yanan and Zhongwei and Tongchuan; the contribution of the maximum daily SO2 concentration to Beijing is Ordos with an extreme value of 0.005404mg/m3, followed by Xinzhou, 0.00414mg/m3, and is the minimum for Yanan, 0.00008mg/m3; the contribution of the maximum hourly SO2 concentration to Beijing is Xinzhou with an extreme value of 0.03708mg/m3, followed by Ordos, 0.01815mg/m3, and is the minimum for Zhongwei, 0.00029mg/m3. (4) For the purpose of improving the air quality, it is critical that its contribution to the surrounding regions should be circumscribed in addition to the consideration of its local influence in the pollution control and countermeasure of a single city.

Impact of the Protective Materials on Explosion Driving Reactive Fragments

SUN Wenxu;LI Shangbin;HUANG Hengjian;WANG Donglei;LU Zhonghua;JIANG Zhihai
Science & Technology Review. 2011, 29 (16): 30-34. ;  doi: 10.3981/j.issn.1000-7857.2011.16.002
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Abstract ( 1749 )
In this paper, the detonation driven process of reactive fragment is studied. The priming of the donor explosive, the spread of detonation wave, the effect of protective materials and the driven process of the fragment are simulated by AUTODYN-3D finite element analysis software. Based on the characteristics of the fragment warhead, a mathematical model is proposed for the relationship between the initial velocity and the structural parameters of fragment projectile including the high explosive charge, explosion-interrupted material, fragments and other components. Based on a study of the attenuation law of the shock wave in different media, the explosion driving process of three typical materials is mainly analyzed. The results show that the shock load in the energetic fragment is significantly decreased by using the interrupted material to ensure no break and reaction in energetic fragments. Through theoretical analysis and numerical simulation, the influence of the shock wave attenuation of the interrupted material on the initial velocity of the energetic fragment is analyzed. A comparison between the theoretical model and the numerical simulation is made. The results provide some insight for the design of the energetic fragment warhead.

Synthesis of Ammonia-free Compound Gel and Its Gelation Characterization

YU Shuijun;JIA Boyu;WU Shuaidong
Science & Technology Review. 2011, 29 (16): 35-38. ;  doi: 10.3981/j.issn.1000-7857.2011.16.003
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Abstract ( 895 )
In order to improve fire extinguishing properties and thermal stability of gel, the gelation characteristics of ammonia-free compound gel were investigated by photoelectric analysis. The gelling time of ammonia-free compound gel was measured by photoelectric method and the effect of temperature on gelling time of compound gel was analyzed and the thermal stability of plain gel and compound gel were compared with each other in different environments. The results show that the gelling time of compound gel shortens rapidly with temperature increasing and the influence of environmental temperature on the gelling time has a relationship with the mass fraction of compound gel, the degree of influence is that 6% gelatinizing agent>8% gelatinizing agent>10% gelatinizing agent. Adding gelling agent composed of varied complex Lewis acid to Na2SiO3·nH2O solution could counteract the charge of the micelle silicate, damage the fusion membrane of the micelle silicate, and promote colloidal particle coagulation in order to convert into full of flexibility. Because the composite gelling agent is crushing polyhedron, the increases of specific surface area and water absorption improve the thermal stability of the gel.

A New Wavelet Entropy Method Based on the EEG Rhythm Characteristics

XIAO Yi;CHEN Shanguang;HAN Dongxu
Science & Technology Review. 2011, 29 (16): 39-44. ;  doi: 10.3981/j.issn.1000-7857.2011.16.004
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Abstract ( 445 )
The analysis of the influencing factors of the wavelet entropy is not simple, which involves the cognitive analysis based on the wavelet entropy of EEG, so some selection and calculation principles of the decomposition level and Pn should be determined. A new wavelet entropy method based on the EEG rhythm characteristics is proposed in this paper, which takes all subspaces of each rhythm as a unit, then calculates the wavelet entropy based on the power of the rhythm. The relationships between the EEG and the wavelet entropy are established by the method. The method is verified in detail by the BCI IV EEG data. Furthermore the relationships between the EEG wavelet entropy and the EEG characteristic are further explored. The method provides an important way for further physiological analysis of the EEG, and the relationships between EEG-rhythm characteristics, EEG wavelet entropy and cognitive features are established by the method.

Seepage and Liquation Stability on the Heightening Tailings Dam

FENG Meisheng;WANG Laigui;ZHANG Hongzhu;
Science & Technology Review. 2011, 29 (16): 45-48. ;  doi: 10.3981/j.issn.1000-7857.2011.16.005
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Abstract ( 1173 )
For the heightening designing of tailings dam, the dam's stability assessment is needed. In accordance with the borehole data, by combined with the heightening design scheme, the geological model of the tailings dam is established. Tailings dam's seepage stability, static stability, and dynamic stability under the flood and earthquake work condition are calculated. The results show that there is no infiltration of the overflow from the slope and the seepage is stable; the safety factor meets the regulatory requirements and the dam is in the static stability; dynamic responses and liquefaction results of the dam show that the dam is stable. A comprehensive assessment of the stability line is provided. It possesses certain significance in the evaluation of seepage, static stability, and dynamic stability based on the principle of effective stress.

Method of Denoising Seismic Random Data Based on Improved FastICA

ZHANG Xiaofeng;XU Jianghao
Science & Technology Review. 2011, 29 (16): 49-53. ;  doi: 10.3981/j.issn.1000-7857.2011.16.006
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Abstract ( 409 )
An improved fixed-point algorithm is used to solve the ICA problem accompanied with noise. According to the noise distribution, it takes two phases to eliminate random noises of different types in preprocessing. The additive white Gaussian noise is removed at first, then the Improved FastICA algorithm is used to process the preprocessed data and to blindly separate the effective signal from non-Gaussian random noise. It might be a problem to set a good starting value in the iterative process of Improved FastICA. In this way, one can accurately set the starting value to make the algorithm recover the effective signal. The satisfactory separation results and better recovery of the effective signal are achieved as shown by the simulation experiments and real seismic data processing. Furthermore, in the case of the strong seismic noise with actually loaded and reduced SNR, this algorithm of blind separation also produces good results. This verifies that the algorithm has good robustness and adaptability. Using the algorithm of blind separation to do the seismic data enhancement can help to better interprete the seismic data, and promote the development of blind separation technology.

Modeling Cold Heavy Oil Production with Sand

PAN Yi;XIAO Lizhi
Science & Technology Review. 2011, 29 (16): 54-57. ;  doi: 10.3981/j.issn.1000-7857.2011.16.007
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Abstract ( 437 )
Heavy oil is the most important resource to supplement the loss of oil in the 21st century. The International Energy Agency (IEA) estimates that there are 6 trillion barrels of heavy oil worldwide. Currently, the standard heavy oil production is based on steam injection, which faces a great challenge because of the sand production, gas channelling, and high costs. Cold Heavy Oil Production with Sand (CHOPS) has extremely good primary performance, high oil production rates, high primary recovery factors, and low operational costs. In this paper, the mathematical and numerical descriptions are given for the sand production within the context of continuum mechanics and finite dements, with emphasis on the physics of the sand production and its relation to the interaction between hydrodynamics and geomechanics. A mathematical model is proposed based on the erosion mechanics, while the instability associated with the sand production is treated within the framework of the high gradient continuum mixture theory. Numerical results of the proposed model are in good agreement with the oil field data, which shows that the model could be applied to predict the oil production and to provide a guidance to adjust the explore strategy. Moreover, the influencing factors, such as oil viscosity, producing pressure drop and information coefficient on CHOPS performances are discussed, which helps to determine what kind of reservoir is relevant for the application of the CHOPS. At last, the advantages and disadvantages of the model are discussed in detail and the future work of modeling cold production is commented.

Main Influencing Factors of Capacity of Dagang Underground Gas Storage Facilities

XU Hongcheng;LI Juan;LI Hongchun;TANG Ligen
Science & Technology Review. 2011, 29 (16): 58-61. ;  doi: 10.3981/j.issn.1000-7857.2011.16.008
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Abstract ( 605 )
The working gas volume is still lower than the design value after nearly ten injection-withdrawal cycles in some of Dagang underground gas storage facilities in China. Multicycle dynamic analysis was conducted by focusing on the performance of underground gas storage facility, injection-withdrawal wells and observation wells based on the geological and production characteristics of the gas reservoir, and then the main influencing factors of the working gas volume were analyzed, including geological condition, water flooded degree, development mode of gas reservoir, injection-withdrawal well pattern and injection-withdrawal mode of underground gas storage. This analysis provides a scientific basis for operational management and design, and also for constructing the same type of underground gas storages.
Reviews

Development Trend of Chinese Integrated Circuit Industry and Science and Technology in 21 Century

WANG Yangyuan;WANG Yongwen
Science & Technology Review. 2011, 29 (16): 62-74. ;  doi: 10.3981/j.issn.1000-7857.2011.16.009
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Abstract ( 741 )
This paper briefly reviews the history of the world economics and the development of integrated circuit industry. It is indicated that "Green Micro-Nanoelectron" will become a significant component of the low-carbon economic society. In this context, this paper analyzes the market of China's integrated circuit, the present status of China's IC industry and IC technology, the opportunity and challenges for the main land of China. This paper also discusses the Micro-Nano new structure device, the green integrated circuit manufacture, the development trend of low-power IC design. It is thought that reducing energy consumption and raising the rate of performance of power consumption are going to be the main driving force for the development of ICs and the systems. Finally some comments are made concerning the development goal of China's IC industry, including the fields of technology progress, institutional reform, talent cultivation and industry environment. This paper is divided into four chapters. (1) Chapter one addresses the neo-industrialization in the mainland of China and reveals the objective laws governing the development of an industrial society. (2) Chapter two shows that China is still in the stage as a leading power of IC consumption. (3) Chapter three describes the development road of the IC industry in the mainland of China. There are five points worth mentioning. Firstly, China is a lake of information industry's core competency. Second point concerns the relationship between IC development and energy consumption. Thirdly, the planning of industrial breakthroughs in China is to give a high priority to the design industry and the innovative design should be based on the system requirements and low power consumption. Fourthly, China should reinforce the manufacturing industrial foundation, raise the technical level, strengthen the serviceability and save energy consumption. Fifthly, China should grasp the historic opportunity in the 2020—2030s and make significant breakthroughs in the IC science and technology. (4) Chapter four illustrates that the institutional reform and the cultural evolution are the essential conditions of the sustainable development for IC industry in particular and the science and technology in general.

Progress in Noninvasive Diagnosis of Liver Fibrosis in Patients

JIANG Yongfang;LI Naiping
Science & Technology Review. 2011, 29 (16): 75-79. ;  doi: 10.3981/j.issn.1000-7857.2011.16.010
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Abstract ( 483 )
For the prognosis of treatment it is important to timely and accurately evaluate the liver fibrosis in a chronic liver disease. The most reliable diagnosis of liver biopsy available has many limitations, such as the inhomogeneity of liver damage would result in sampling errors and some damage will be done to patients. It is difficult to dynamically observe the process of hepatic fibrosis and fibrosis formation. There is also no reliable way to determine the content of collagen in liver. The diagnose of liver fibrosis based only on a rough estimate has a limited applications. In recent years, a number of combined indicators of liver fibrosis were applied to diagnosis and evaluation. Comprehensive index models for hepatic fibrosis non-invasive diagnosis attract much attention. In order to better understand and apply these diagnostic models, this paper reviews the major progress of non-invasive diagnosis, especially, from two aspects: the serological diagnosis and imaging diagnosis. The limitations and development directions of the current non-invasive diagnosis are discussed. Some food for thought is given for the development of new better comprehensive index models.
科技评论

Science & Technology Review. 2011, 29 (16): 80-80. ;  doi:
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主编心语

Science & Technology Review. 2011, 29 (16): 83-83. ;  doi:
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走向职场

Science & Technology Review. 2011, 29 (16): 86-86. ;  doi:
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