Table of Content

20 November 2010, Volume 46 Issue 6

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Finite Element Analysis during Welding

GAO Yaodong,HE Jianxia,QIAO Yunfang

2010, 46(6):  1007-1009. 

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Based on a simple model, a variety of key issues during the welding simulation were studied about moving heat, latent heat, material parameters. Using finite element software, the authors analyzed the welding temperature field, residual stress field. Results obtained by theoretical analysis agreed with experimental validation. Especially the method that the temperature field was calculated firstly and then structural field was calculated by the indirect method, reduced the nonlinear of the analysis, and improved the computation efficiency greatly. The characteristics performed significantly in the complex model.

Social Cognitive Neuroscience Studies on the Self

HE Xi,ZHU Ying

2010, 46(6):  1021-1024. 

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In the past ten years, neuroscientists have applied brain imaging techniques such as functional magnetic resonance imaging (fMRI) and event-related potentials (ERP) to social cognitive neuroscience studies on the self, and have achieved significant progress. In this essay the authors review the important findings, including the neural substrates of self-referential processing, the differentiation between automatic and controlled processes related to the self, and the neural basis of cultural influence on self-construction. Then the paper discusses the possible research areas in the future, from the perspectives of experimental paradigms, the difference of the self and others, as well as the current situation of cultural neuroscience studies on the self in China.

Environmental Mineralogy and Its Unity Property

LING Hui,SUN Yang

2010, 46(6):  1032-1036. 

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As a new interdisciplinary subject, the development history and theory system of environmental mineralogy which were introduced. The unity property in the intension and extension of environmental mineralogy was discovered. The view was proposed that the intension study of environmental mineralogy should unify theoretical research and practical application, and unify the natural effect and artificial synthesis of environmental mineral materials. From the view of environmental science and mineralogy, the main functions of the extension study of environmental mineralogy were analyzed that it promotes the unity of inorganic mineralogical method and organic biological method in pollution treatment and environmental remediation, and promotes the unity of resource attribute and environment attribute of mineralogy.

Synthesis and Electrochemical Performance Study of Cathode Material Li(Co_xNi_yMn_1-x-y)O₂ for High Power Lithium Ion Secondary Battery

Qilu,JIANG Weijun,WANG Jian,MAO Yongzhi,CHEN Hui,WU Ningning,LEI Xiangli

2010, 46(6):  863-869. 

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High capacity and high voltage composite metal oxide Li(Co_xNi_yMn_1-x-y)O₂ used in high power lithiumion secondary batteries was synthesized by chemical method. 8 Ah high power lithium ion batteries with this cathode material were fabricated and studied, and the battery system were tested in Hybrid Electric Vehicle (HEV). The results show that the battery system holds excellent cycle performance and uniformity. Furthermore, the highest temperature increase of individual batteries is just 5℃ which means the battery system holds good thermal stability. Consequently this battery system fits HEV very well.

Community Structure Characteristics of Zooplankton in Argun Drainage Area in Autumn

JIANG Ying,YAO Jinxian,PANG Ke,WANG Hao,LIU Songtao,LvZhi

2010, 46(6):  870-876. 

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Among August-September 2008, the authors collected zooplanktons from Argun drainage area which included Hulun Lake, Erka Marsh, Wulan Lake, Gen River, Yimin River and Hawuer River. A total of 52 species belonging to 42 genera were identified. Rotifers were 18 species ( 34. 6% of the total) of 15 genera; Cladocerans 14 species ( 26. 9% ) of Erka Marsh had the most species, respectively 36 and 34. Gen River and Hawuer River were below 10 species. Erka Marsh had the most density and biomass (4650. 5 ind/ L and 2. 29 mg/ L, respectively) ; then Hulun Lake and Wulan Lake ( 2274. 5 ind/ L, 1. 35 mg/ L and 4180. 1 ind /L, 1. 18 mg/ L, respectively); Gen River, Hawuer River and Yimin River had the least density and biomass. According to the water trophic status indicators from species number, density and average biomass, Erka Marsh, Hulun Lake and Wulan Lake were mesotrophic waters; Gen River, Yimin River and Hawuer River were oligotrophic waters. Meanwhile, the structure shift of zooplankton community in Hulun Lake indicate increasing in chemical nutrients.

Variable Structural Dynamics for a Two-Dimension Rod

CAI Huiping,ZHAO Zhen

2010, 46(6):  877-881. 

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Contact, impact and friction may induce none-smooth behaviors on velocity level for multi-rigid-body system. Variable structural dynamics can deal with them by loading and uploading constraints on the system. Variable structural dynamics for two dimensional dynamic system including contact, impact and friction is introduced. A 2D rod is presented to achieve the final dynamic simulation.

An Approach to Auto-detection, Segmentation and Tagging of Bibliographic Metadata

GAO Liangcai,TANG Zhi,TAO Xin,FANG Jing

2010, 46(6):  893-900. 

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After reviewing the existing methods on citation data extraction, the authors propose a new approach for the task depending on a common typesetting practice of bibliographies: style consistency of citation data in the same document. Citation data detection and segmentation task are described on which less attention is put in previous researches. Furthermore, the authors take advantage of the style consistency of bibliographies to enhance citation metadata tagging. Experimental results show that the proposed method performs well in citation data detection, segmentation and tagging.

STBC-OFDMA Uplink Transmission Based on Combination of User Grouping and Frequency Reuse

GUO Junqi,SHANG Yong,REN Shubo,XIANG Haige

2010, 46(6):  882-892. 

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A space-time block coded orthogonal frequency division multiple access (STBC-OFDMA) scheme based on combination of user grouping (UG) and frequency reuse (FR) is proposed for WiMAX uplink transmission where each user employs an STBC scheme. First, a direction-of-arrival (DOA)-based intra-cell UG model is combined with the idea of inter-cell FR so as to produce a UGFR-STBC-OFDMA uplink access scheme which satisfies with both UG constraints and the inter-cell FR planning. Furthermore, a Capons beamforming-based receiver with a smart antenna array is proposed for directional reception of signals coming from different user groups as well as multiple access interference (MAI) suppression at the base station. Both theoretical analysis and simulation results show that the proposed uplink access scheme not only achieves a well-behaved tradeoff in ideal average spectral efficiency, bit error rate (BER) and computational complexity, but also suppresses inter-cell interferences without power control, compared with some conventional schemes for uplink transmission.

Study on the Dolomitization and Dolostone Genesis

HE Yunlan,LIU Bo,QIN Shan

2010, 46(6):  1010-1020. 

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In order to trace back the resource of Mg²⁺, studying on a lot of examples of the dolostone origins, then finding that in geological environment, the Mg is mainly from diagenetic liquid, magmatite and other solid minerals, and Mg²⁺ organism. Mg²⁺ replaced Ca²⁺ of calcite under special hydrokinetics mechanism while dolomitization occurred. Based on the Mg²⁺ resource and hydrokinetic mechanism, the dolomitization models, accepted by most people, can be divided into evaporation model (Sabkha model), seepage-reflux model, mixing-water model, marine dolomitization model, deep burial model and hydrothermal model. Based on the different buried conditions, dolomitization can be grouped into three kinds: shallow dolomitization ( < 1000 m) , mid-deep dolomitization ( 1000-2000 m) and deep dolomitization ( > 2000 m).

Social Pain: Evidence from Physical Pain

SHU Min,LIU Pan,WU Yanhong

2010, 46(6):  1025-1031. 

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Social pain refers to a specific emotional reaction to the perception that one is being excluded from desired relationships or being devalued by desired partners or groups. It has a close relationship with physical pain, and it might be understood in terms of finding out the convergence between two types of pain. This paper introduces the concept, function, psychological correlates and neurophysiological mechanisms of social pain, moreover, discusses its possible research area.

Relationship between Distance and Binaural Cues on Sound Source Localization

QU Tianshu,CAO Songwei,WU Xihong

2010, 46(6):  901-906. 

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Three HRTF databases were set up for investigating the relationship between distance and interaural cues (including ITD and IID). The first database is from the calculated spherical head model, the second is the distance-dependent HRTF database for KEMAR manikin, and the third is the distance-dependent HRTF database for KEMAR manikin without pinnae. The results using the three databases confirm that distance play an important role in affecting the interaural cues in proximal region.

Chinese Textual Image Compression Based on Multi-feature Extraction

HU Kui,TANG Zhi,GAO Liangcai

2010, 46(6):  914-920. 

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Based on the characteristics of Chinese textual images, an improved compression algorithm MC-JBIG2 is developed. First, multilevel feature data of Chinese characters are extracted; then the data are used in a cascaded clustering algorithm to replace the pattern matching procedure of JBIG2. Experiment results show MC-JBIG2 is highly efficient and can improve compression ratio in the criterion of not involving substitution errors. Despite designed for Chinese textual images, MC-JBIG2 can also improve compression ratio of English textual images.

Acquisition Circuit for HSGPS Receivers: Optimization and Implementation

LU Weijun,HUANG Yongcan,YU Dunshan,ZHANG Xing

2010, 46(6):  907-913. 

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The authors propose an optimizing method for the energy detector based on the parallel correlators in the time domain. With a method named as two-step correlation method and time sharing techniques, all the 1023 chip phases are detected in parallel. When the sampling frequency is 16. 368 MHz, the total correlator number is reduced to be 1/ 102. 3 of the non-optimized counterpart. Furthermore, the energy detector using the proposed method is implemented by FPGA and synthesized with Design Compiler. The test results show that when pre-detection time is 2s, C/N₀ = 21 dB-Hz, and false alarm is 0. 097% , the detection probability is as high as 90% .

Design of On-Chip ADC for Readout Circuit of Microcantilever-Based Infrared Focal Plane Array

CAO Junmin,CHEN Zhongjian,LU Wengao,ZHANG Yacong,YU Xiaomei,ZHAO Baoying

2010, 46(6):  921-925. 

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An on-chip ADC for readout circuit (ROIC) of microcantilever-based infrared focal plane array (IRFPA) is presented. Pipeline structure is employed for power and area efficiency. Multi-bit first stage with overflow detection and stage scaling down are adopted to optimize the power dissipation of ADC. The prototype ADC is fabricated in 0. 35μm CMOS process. Measurement results show that the power dissipation is 98 mW from a 5V supply, DNL and INL is - 0. 8/ 0. 836 LSB and - 0. 9/1. 6 LSB, respectively. With a 1 MHz input signal, the ADC achieves 82dB SFDR and 67 dB SNDR at 10 M samples/s.

Application of Network Generalized Extreme Value Model to Estimate Residential Location and Commute Mode Choice

LI Xia,SHAO Chunfu,QU Tianshu,YANG Liya,WANG Jiangfeng

2010, 46(6):  926-932. 

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Relationship between jobs-housing spatial distribution and travel to work were studied from a microscopic perspective. Based on random utility maximization theory, factors depicting the individual and socio-economic characteristics and attribute of travel and land use are defined as exogenous variables, meanwhile, the model choice sets are the combination of residential location choice and commute mode choice subsets. Discrete choice model specified as Network Generalised Extreme Value(NetworkGEV) is employed to investigate the joint decisions of where to live and how to get to workplace which attempts to describe the change of aggravated traffic congestion and discover the potential change caused by residential relocation and travel mode shift under different employment location patterns. This model is estimated in Biogeme, and the direct and cross elasticities are calculated to analyze the change of alternatives probability brought by factors variation. The results reveal that the model yields plausible estimation of exogenous variables in the joint residential location and travel mode choice context. Compared with suburban commuters, commuters in CBD are more sensitive to the increase of travel time and intend to change travel mode and residential location thus trading off the disutility of traffic congestion.

Research on Methods Constraining Shear-Wave Splitting and Geodynamical Implication of Shear-Wave Splitting in China

WANG Rui,MA Zhitu,Li Fei,Zhou Shiyong

2010, 46(6):  933-941. 

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Shear-wave splitting is the most simple and direct seismic method to understand the anisotropic property of the earth. The result has important meaning in geodynamics and valuable in the research of earthquake prediction. The authors use the methods proposed by SC1991 and WS1998 to constrain the splitting parameters by analyzing SKS and SKKSphases. The records from 2001 to 2005 are provided by Chinese Seismology Network Center (CENC). Great discrepancies are observed. The splitting time in South-West, South, and North-West part of China is shorter than Middle and Middle-West part of China. Similar patterns between fast direction and GPS velocity direction show coupling effect between lithosphere and asthenosphere. Fast directions are also parallel to plate boundaries in convergent regions and identical to the strike of transcurrent fault. This may imply the coherent deformation between crust and mantle. The length of time window, the possibility of ray-splitting and the dependence of fast direction to back-azimuth are also discussed.

Estimation of the Net Radiation over Arid and Semiarid Areas Only Using MODIS Data for Clear Sky Days

YE Jing,LIU Huizhi,LI Wanbiao,CAI Shuangpeng,LI Yuming,CAO Lixia

2010, 46(6):  942-950. 

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Based on the parameterization of downward shortwave radiation, upward shortwave radiation, downward longwave radiation and upward longwave radiation above the surface, a scheme is proposed to estimate instantaneous net radiation over arid and semiarid areas for clear sky days using only remote sensing observations. The scheme attempts to eliminate the need for ground meteorology data as the estimates of land surface radiation balance, by using various land and atmospheric data products available from moderate resolution imaging spectroradiometer(MODIS). The preliminary results, using 89 cases over the degraded grassland and 85 cases over the farmland during July to October in 2003, July to November in 2004 and June to October in 2005, show good agreement with ground-based observations, with the root mean square error of 47. 5 and 49. 2 W/m² respectively, which have better accuracies than the other similar studies.

Constraints on Representative Samples from Crystal Contents and Size in Granitic Rocks

YANG Zongfeng,LUO Zhaohua,HUANG Danfeng,ZHOU Jiulong

2010, 46(6):  951-959. 

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In order to obtain the size of representative samples and its constraints, the relationships of the representative samples with crystal contents and crystal size are preliminarily discussed by statistical simulations of the holocrystalline rocks’texture and the idealized granitic compositions. The maximum possible difference between the original and measured crystal contents of samples, and the size of representative samples are determined under the variations of crystal contents and size. The greatest difference between the original and measured crystal contents of samples can be obtained by counting the number of phenocrysts across the sections of samples. The size of representative samples can be acquired by using the average crystal size. The deviation between the measured and original crystal contents are much more higher for coarse-grained samples with the same sample size. The largest representative samples are needed when the crystal content reach 20% for phenocrysts or coarse-grained minerals in equigranular texture. Finally, two examples including the Mapeng and Fangshan intrusions are used to examine the validity and practicability.

Driving Forces Analysis of Housing Price in Beijing City

HE Chengjie,GUO Huaicheng,WANG Zhen,YANG Yonghui,LIU Hui,SHENG Hu

2010, 46(6):  985-990. 

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Multivariate statistical analysis and hedonic pricing method were employed to analyze the effects of structural variables, including land transaction price, bus lines, distance to downtown area, central business district, railway station and hospital, floor area ratio (FAR), and dichotomous variables, including nearness to rail transit, recreational facilities and parks on housing transaction price in Beijing city. Results indicate that the main determinants of real estate price in Beijing are land transaction price, distance to downtown area, FAR, existence of nearby rail transit and recreational facilities. Among which, land transaction price have a considerably positive effect on transaction price, while FAR and distance from housing to the downtown area are the main negative driving forces for housing transaction price in Beijing.

Characteristics of Eutrophication and Variation Trend of Nitrogen and Phosphorus Nutrient in Shenzhen Bay

SUN Jinshui,WAI Onyx Wing-Hong,WANG Wei,LEI Li,MAO Xiaoling

2010, 46(6):  960-964. 

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Based on the field data in 1986?2007 in Shenzhen bay, annual changes characteristics of nitrogen and phosphate concentrations, as well as their correlations with each other are presented. Furthermore, the Nutrition Quality Index (NQI) is employed to assess the eutrophication degree of Shenzhen bay. The dissolved inorganic nitrogen(DIN) concentration shows an increasing trend, while phosphate( PO^3-₄-P) concentrations decrease gradually. Ammonia nitrogen ( NH⁺₄-N) is the primary form of inorganic nitrogen in Shenzhen bay indicating that inorganic nitrogen is in unstable thermodynamic equilibrium. The ratio of DIN/ P increased gradually before 1998, and decreased after 2002. The variation and components of nutrients could influence the community structure of phytoplankton, and the dominant red tide species have been transformed from diatom to dinoflagellate. Nutrient correlation is significant at the 0.01 level, which shows that the nutrient undergo similar biogeochemistry processes. The NQI shows that Shenzhen bay is in high eutrophic status, and it is urgent resort to effective plan for controlling water pollution in the inflow river.

Assessment of Turbulence State and Analysis of Flux Footprint over Complex Terrain

WANG Xue,CAI Xuhu,KANG Ling,ZHANG Hongsheng,CHEN Jiayi

2010, 46(6):  965-971. 

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The authors used the observed turbulence data in wintertime and summertime of 2006 in Xiaomo Mountain, Hunan Province to study the state of local turbulence. The difference between the observed σ_{u, w}/u_* and the results calculated from similarity function was large, and there was not clear relationship between σ_{u, w}/u_* with wind directions. It is suggested that the local turbulence was generally not developed completely and was easily disturbed. By using a footprint model, it is found that the flux measurements in Xiaomo Mountain were representative of two types of topography: plain region and hilly region. In winter, the northern plain regions played a major role in the overall footprint sources, and the contribution of hilly area only accounted for 21% . While in summer, the influence of southern hilly area was large, with the contribution of 54% .

Chinese Urban Systems in Terms of Domestic Air Flows Since 1995

LI Na,YU Taofang,GUO Huaicheng

2010, 46(6):  972-984. 

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This paper examines the Chinese urban systems in terms of domestic air flows since 1995 based on gravity model and the fuzzy variable method. Main findings are as following: The first and second tier cities of contemporary urban systems are mostly core cities of megalopolis or mega-city regions; Shanghai and Beijing further strengthened their position as national airline hubs and primary cities. And interactions among mega-city regions reflect the uprising of the Yangtze River Delta Region as the leading region of the nation. Based on gravity model analysis, Beijing enjoys the biggest hubness score followed by Xiamen etc. In 1995-2004, the hubness changes can clearly reflect the recent competitiveness of mega-cities or regions.

Chemistry Character of Rain Water at Urban and Rural Areas in the North and Southeast of China

HUO Mingqun,SUN Qian,XIE Peng,BAI Yuhua,LI Jinlong,LIU Zhaorong,LU Sihua

2010, 46(6):  991-998. 

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Samples for rain water were collected at four sites including Beijing city and Mazhuang Town in the north of China and Shenzhen city and Mangdang Mountain in the southeast of China. The pH values of precipitation, values of conductivity and concentrations of major water soluble ions were measured. The pH values of rainwater in Beijing City, Mazhuang Town, Shenzhen City and Mangdang Mountain were 6. 02, 5. 97, 4. 72 and 4. 81, respectively. The most abundant ions in the rainwater included SO^2-₄,NH⁺₄, Ca²⁺ and NO^-₃.SO^2-₄ was still the major acid ion in rain and NH⁺₄ was the most important neutralizing ion at these four sites. While the rainwater in the north of China was more severely polluted than that in the south, the acidity of the rain was greater in the south than that in the north. Enrichment factor was used to analyze the contribution from sea-water, soil and other sources to rainwater. Hysplit 4. 7 Model was used to indicate different chemical characters among different backward trajectories. The chemical characters of rainwater in Mazhuang Town were distinctly different among different trajectories and it was not significant among different trajectories in Shenzhen City and Mangdang Mountain.

Examining the Economic Competitiveness of 18 Districts in Beijing to Obtain Sustainable Urbanization

SUI Xin,Bjorn Harsman,JI Guodong

2010, 46(6):  999-1006. 

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The authors analyzed the relative economic performances as measured by gross domestic product (GDP) among 18 districts in Beijing between 1993-2002 and 2005-2007. The statistical models use a traditional shift-share analysis evaluated with SPSS software. District competitiveness was decomposed into ten selected factors, including resource utility and environmental quality. The results indicate that, between 1993-2002, districts in the city-center were more competitive than districts in the suburbs. After 2005, suburban districts increased their competitiveness at a faster rate than those in the city. In addition, the authors try to identify the driving forces of economic growth in Beijing. Five factors were found to have a significant impact on GDP competitiveness of 18 districts in Beijing; finance income, employment density, average wages, and air quality all had positive effects, while population density had a negative effect. These results will be useful for planning future economic growth and specialization for districts around Beijing.