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   Science & Technology Review
2011, Vol.29, No. 28
08 October 2011

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卷首语

Science & Technology Review. 2011, 29 (28): 3-3. ;  doi:
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科技风云

Science & Technology Review. 2011, 29 (28): 7-7. ;  doi:
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封面图片说明

Science & Technology Review. 2011, 29 (28): 8-8. ;  doi:
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特别栏目

Science & Technology Review. 2011, 29 (28): 8-8. ;  doi:
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Science & Technology Review. 2011, 29 (28): 10-10. ;  doi:
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Science & Technology Review. 2011, 29 (28): 12-12. ;  doi:
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Science & Technology Review. 2011, 29 (28): 13-13. ;  doi:
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Science & Technology Review. 2011, 29 (28): 14-14. ;  doi:
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Science & Technology Review. 2011, 29 (28): 32-32. ;  doi:
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Science & Technology Review. 2011, 29 (28): 88-88. ;  doi:
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Science & Technology Review. 2011, 29 (28): 95-95. ;  doi:
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Science & Technology Review. 2011, 29 (28): 96-96. ;  doi:
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科技事件

Science & Technology Review. 2011, 29 (28): 9-9. ;  doi:
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科技工作大家谈

Science & Technology Review. 2011, 29 (28): 11-11. ;  doi:
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Exclusive

Science & Technology Review. 2011, 29 (28): 15-19. ;  doi:
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Articles

A New Design of the Vacuum System for the Aging Tests of the Space Infrared Device

CAO Lan;YANG Bo;ZHU Xianliang;ZHANG Haiyan;GONG Haimei
Science & Technology Review. 2011, 29 (28): 20-23. ;  doi: 10.3981/j.issn.1000-7857.2011.28.001
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Abstract ( 316 )
Based on the requirements of the vacuum system for the new aging tests of the space infrared device, this paper presents a design of a fully automatic high vacuum exhaust station with two sets of pumping system. One is the main vacuum system with a mechanical pump and a molecular pump as the backing pump and a sputter ion pump as the main pump; the other is the auxiliary vacuum system composed of a mechanical pump and a molecular pump, used for pre-pumping. With the computer control technology, this multi-station structure system enjoys automatic functions. The theoretical calculation analysis shows that this system can meet the vacuum requirements for the aging tests of the infrared device.

Analysis of Anti-reconnaissance Capability of a New Combined Modulation Detector

XUN Yang;CUI Zhanzhong;HAO Xinhong
Science & Technology Review. 2011, 29 (28): 24-27. ;  doi: 10.3981/j.issn.1000-7857.2011.28.002
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Abstract ( 283 )
A novel combined modulation detector with a combined format of Pseudo-Random-Binary-Phase Code (PRBPC) and Linear Frequency Modulation (LFM) is proposed. Its anti-reconnaissance capability is analyzed from three aspects. The reconnaissance distance for the reconnaissance equipment to scout the combined modulation signal is derived; a model of parameter acquisition probability is established with the help of the window function theory; the expression for the probability of intercept parameters is obtained; the distance cut-off feature of the combined modulation signal is achieved by the half-width of the main lobe of the signal autocorrelation function. The combined modulation waveform is compared to the single LFM signal and the single PRBPC signal during the analysis. The computed results of the three aspects for typical parameters show that the combined modulation detector has a quite large reconnaissance distance due to its short-range working environment, the parameter acquisition of the combined modulation signal is very low, and its distance cut-off feature is very incisive. It is concluded that the combined modulation detector enjoys a strong anti-reconnaissance performance.

Modelling and Simulation of 3D Laser Imaging Detection System

YAN Xiaowei;DENG Jiahao
Science & Technology Review. 2011, 29 (28): 28-32. ;  doi: 10.3981/j.issn.1000-7857.2011.28.003
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Abstract ( 319 )
Simulation is an effective method to evaluate the performances of existing laser imaging systems and to develop novel laser imaging detection technologies. The characteristics of laser pulse returned signals and the establishment of the related models are of vital importance for the echo signal processing and the laser imaging simulation. This paper studies the modelling procedure of the returned signals based on the laser transmitted pulse model, and the modelling method for target scattering properties based on the unit impulse response is discussed in detail, to deveop detection algorithm models. The simulations of 3D laser imaging based on linear array scanning in the pushing-broom are carried out by means of arraying the single return detection. The results show that the laser imaging simulation can yield the simulated images effectively under a wide variety of conditions.

Identifications of Underwater Acoustic Communication Signals Classification Based on Time-frequency Analysis and Neural Network

LU Yang;WANG Xuesong;ZHAO Pengyuan;ZHOU Hua
Science & Technology Review. 2011, 29 (28): 33-36. ;  doi: 10.3981/j.issn.1000-7857.2011.28.004
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Abstract ( 416 )
The fast detection of communication signals and the exact identification of their modulation types are of importance in practice. Traditional designs use detectors for each modulation type separately thus the computation time would increase as the number of modulation types increases. It is necessary to work out a standard feature vector extraction method to reduce the number of detectors. A novel identification scheme is proposed, with feature vectors being extracted from the time-frequency distribution and identified by an artificial neural network. By adding signal samples of new modulation types and by retraining the neural network, this identification scheme can recognize more modulation types without increase of computation burden. The detail of this feature vector extraction approach is described, the probability of the correct identification of the communication signals in low signal-to-noise conditions is obtained through computer simulations.

Mosaics of Multi-source Radar Echoes in Central Region of Inner Mongolia Based on GIS

YU Xuetao;YU Zhiwei;RUI Xiaoping;XI Yantao;DONG Qianlin;
Science & Technology Review. 2011, 29 (28): 37-42. ;  doi: 10.3981/j.issn.1000-7857.2011.28.005
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Abstract ( 579 )
In order to monitor the regional weather in the central region of Inner Mongolia in real time, the radar mosaic obtained from the base reflectivity products of the new generation of weather radar and the Plane Position Indicator(PPI) echoes from 713 radar is studied. Firstly, the storage structure of the two types of echo data is analyzed in detail. And then, a translation algorithm is developed to turn both types of data into two-dimensional matrices, and the drawing mode of converting both types of files to the raster files under the rectangular coordinate system is used, and implemented by ArcGIS Engine. Finally, the paper considers the radar mosaic obtained from the two types of echo images, and has designed and developed the regional echo mosaic platform to merge the four radar echo images in real time according to the user's requirements. The application of this system produces very good results in the weather bureau of Baotou City, and it is shown that this platform can monitor the regional weather in the central region of Inner Mongolia in real time, to supply supplementary decision information for weathermen to make weather forecast and warning.

PCB Image Enhancement Algorithm Based on Double Sigmoid Transform

GUO Fenglin;GUAN Shu'an
Science & Technology Review. 2011, 29 (28): 43-45. ;  doi: 10.3981/j.issn.1000-7857.2011.28.006
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Abstract ( 565 )
In the Printed Circuit Board (PCB) defect detection based on Automatic Optic Inspection (AOI), the actually collected PCB images are often blurred over the edge, especially in the area of dense vertical lines. Therefore, to eliminate noise and enhance the image to highlight the edge, which makes the alignment between PCB sample and the detected PCB easer and more precise and avoid missing and false detection, are needed. The main target for enhancing PCB images is to sharp the edges, at the same time to effectively suppress noise, especially the noise near the edges. From the perspective of the edge sharpening, the differential operation should be used. However, for filtering out the noise, integral operation should be applied to. Based on the above features, a new image transformation i.e. double Sigmoid transformation, which imposes a double transformation on the original image and at the same time uses the results with the transformation to enhance the original image, is presented. At first, a definition of Sigmoid transformation is given, and then double Sigmoid operators are deduced. In order to simplify the computing, only a set of special feature value is taken to calculate the sigmoid operator, which makes the computing speed faster. Experiments show that the Sigmoid algorithm could effectively sharpen PCB image edges, at same time, filter out noise in the image. Even if the original PCB image is not distinct enough and uniform brightness, the algorithm is still able to precisely locate circuit edge, which could make the edge extracting and edge recognition easier.

Topography Evolution of Joint Surface Under Shear Loads

CAO Ping;ZHOU Han;FAN Xiang;HUANG Xuejiao;CHEN Yu;
Science & Technology Review. 2011, 29 (28): 46-51. ;  doi: 10.3981/j.issn.1000-7857.2011.28.007
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Abstract ( 328 )
It has been long recognized that the roughness of rock discontinuities could have a significant impact on the shear strength characteristics of discontinuous rock masses. In order to study topography evolution of joint surface after shear tests, five samples were sheared two times and joint surfaces were scanned before and after each shear test with the 3D non-contact high-accuracy laser topography instrument (Talysurf CLI 2000). Topography evolution of joint surface is both macroscopically and microscopically analyzed, and the following conclusions are gotten: (1) the peak shear strength is related to the topography of joint surface; (2) after two shear tests, the number of peaks for the higher height of joint surface decreases, while that for the lower height of joint surface increases; (3) after two shear tests, the maximum height of joint surface decreases, the height of most asperities drops and the number of middle-height asperities rises; (4) after two shear tests, both of the envelope and the mean profile of joint surface tend to go down, and the descending height is related to the normal stress.

Prediction of Borehole Stability During Drilling of Directional Wells

DOU Ninghui;WU Chao;CHEN Mian
Science & Technology Review. 2011, 29 (28): 52-56. ;  doi: 10.3981/j.issn.1000-7857.2011.28.008
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Abstract ( 339 )
In recent years, with the increasing complexity of the exploration and development geological environment, the number of complex wells increases, and subsequently, the borehole stability becomes more and more an issue. This paper proposes a method to predict the borehole stability during drilling of directional wells based on a geological statistical analysis. Firstly, the seismic and logging data of drilled wells are analyzed, and then through the geostatistical collocated co-Kriging simulation combined with the sequential Gaussian simulation, the 3D data body of rock mechanics parameters for the whole block are predicted. According to the trajectory to be drilled, the parameters of rock mechanics for the wellbore trajectory are extracted and by using the models for collapse, fracture and pore pressure of the directional well, the prediction model for the corresponding stratified rock mechanics is built. The accuracy of the prediction can be evaluated in comparison with the logging data and by adjusting the parameters of the model, the model can be updated and refined to improve the prediction accuracy.

Determination of Reasonable Slope Angle and the Evaluation of Slope Stability for the No.1 Open-pit Mine in Baiyinhua

FAN Junfu;SONG Ziling;WANG Dong
Science & Technology Review. 2011, 29 (28): 57-61. ;  doi: 10.3981/j.issn.1000-7857.2011.28.009
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Abstract ( 499 )
In order to guarantee the slope safety of coal mining in Baiyinhua No.1 open-pit mine, a reasonable angle of slope has been determined and slope stability has been analyzed and evaluated. On the basis of careful analysis on engineering geology, hydrogeology, slope rock's physical and mechanical properties of materials actually exposed layer of each section, combining the past landslides for the No.1 open-pit in Baiyinhua, using slope numerical calculation software FLAC3D, the slope stability of No.1 open-pit in Baiyinhua is analyzed and researched in detail, then the reasonable slope angles for the No.1 open-pit mine in Baiyinhua are identified. At the same time, the effects on slope stability for refuse dump inward open pit mines are researched to track in the mining process. The results show that a reasonable distance from the inner row of track might increase slope angle. It is feasible to improve coal recovery in the open-pit mine. A theoretical basis is provided for the open-pit mining in Baiyinhua.

Quantitative Classification and Evaluation of the Flow Unit in Chengdao Oilfield

GUO Zhi;SUN Lianzhi;ZHANG XiaoLei;CHEN Guoning;LUO Haining
Science & Technology Review. 2011, 29 (28): 62-67. ;  doi: 10.3981/j.issn.1000-7857.2011.28.010
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Abstract ( 313 )
The flowing unit is very important in the study of reservoir heterogeneity and the remaining oil distribution. In the current research methods for flow units, the seepage barrier distribution between the flow units is not well accounted for, too much emphasis is paid on the flow units in the vertical stratification, and the evaluation parameters are not adequate. To solve these problems, this paper considers the upper part of Guantao group strata of 12 and 20 well zones in Southern District of Chengdao oilfield. Combining logging, geological, and development data and other information, several parameters that would reflect the seepage features of the reservoirs are selected such as porosity, permeability, median grain size, clay content, sand body thickness, net/gross ratio, in an analytical hierarchy process, based on the analysis of sedimentary facies and the identification of seepage barriers, the flow units are studied by the cluster and discrimination method. The flow units in this area are divided into four kinds: E, G, M and P, and the formulas for these four kinds of flow units are derived. Compared with the production data, it is found that the distribution of major reservoirs and E-type flow units are in good agreement, showing that the study of flow units can provide a feasible means for the analysis of the heterogeneity and the distribution of remaining oil.

Effect of Abnormal Savda Munziq on Morphological Structure of Hepatic Tissue in Hepatocirrhosis Phase of Hepatocarcinoma Carrying Abnormal Savda Model

ABDUZAYIR Abliz;UPUR Halmurat;TURSUN Yusup;KURBAN Abdukadir;BAKRI Iskandar
Science & Technology Review. 2011, 29 (28): 68-73. ;  doi: 10.3981/j.issn.1000-7857.2011.28.011
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Abstract ( 501 )
This paper discusses the effect and possible mechanism of abnormal savda munziq on the morphological structure of hepatic tissue in hepatocirrhosis phase of hepatocarcinoma carrying abnormal savda model. According to the theory of Uighur traditional medicine, multi-complicated induction methods were adopted to establish the hepatocirrhosis phase of hepatocarcinoma carrying abnormal savda disease rat model, three other drug groups were given three different dosages (1.5, 3.0, 6.0 g/kg) of abnormal savda munziq during the whole procedure, and the pathological and ultrastructural changes of the liver in the 7th, 11th, 15th weeks were observed dynamically. The result shows that at the same point in time, the pathological and ultrastructural changes of the liver in the low dose group have not been improved significantly compared with that of the abnormal savda syndrome model group, while there have been significant improvements in the middle dose group and high dose group compared with the abnormal savda syndrome model group, such as reduction of connective tissue hyperplasia, reduction of interstitial infiltration of inflammatory cells, reduction of the degree of edema of liver cells, ultrastructural changes of uneven distribution of liver intracellular organelles and gradual reduction of liver glycogen and mitochondrial. These findings indicate that abnormal savda munziq can protect and recover the morphological damage on hepatic tissue in hepatocirrhosis phase of hepatocarcinoma carrying abnormal savda model.
Reviews

Network Motif: The Smallest Unit of a Biological Network

CHEN Changshui;LIU Shaofei
Science & Technology Review. 2011, 29 (28): 74-74. ;  doi: 10.3981/j.issn.1000-7857.2011.28.012
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Abstract ( 480 )
The network motif (motif for short) is the smallest decomposable unit of a biological network or its smallest building block. It is an important research issue in systems biology. Motifs exist in various types of biological networks with information-processed functions. Simulations and experiments were carried out to study their dynamical properties. This paper reviews the styles and functions of motifs and the databases and tools to find motifs. The motifs we discuss in the paper include Negative Auto-Regulation(NAR), Positive Auto-Regulation (PAR), Forward Feedback Loop(FFL), Single Input Module(SIM), Multiple Input Modules (MIMs), regulator chain motifs, multi-component loop, bridge and brick motif in transcriptional networks, and motifs in signal transduction networks, as well as those in neural networks. The motifs might be viewed as the electric devices. This review also discusses the properties and the evolutions of network motifs, and related applications to synthetic biology. Finally, it is pointed out that the network motif study might be the first step in the studies of biological networks in systems biology to provide a good research method to study the module and synthetic biology. More types of motifs in various networks should be found out and more in-vivo experiments should be carried out. The further study might produce some general principles in biological networks.
科技评论

Science & Technology Review. 2011, 29 (28): 80-80. ;  doi:
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主编心语

Science & Technology Review. 2011, 29 (28): 83-83. ;  doi:
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走向职场

Science & Technology Review. 2011, 29 (28): 84-84. ;  doi:
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Science & Technology Review. 2011, 29 (28): 85-87. ;  doi:
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Science & Technology Review. 2011, 29 (28): 89-92. ;  doi:
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