Table of Content

20 September 2007, Volume 43 Issue 5

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A New Component of Core Self-Evaluation in Predicting Burnout：Collective Self-Esteem

GAN Yiqun,XI Zhuangzhuang,HU Yueqin,ZHANG Yiwen

2007, 43(5):  709-715. 

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The objective of the present study is to identify the structure of core self-evaluation and explore its relationship with burnout among Chinese college students. One hundred eighty-four university students completed the Maslach Burnout Inventory-Student Survey (MBI-SS), Rosenberg Self-Esteem Scale (SES), General Self-Efficacy Scale, Rotter's Locus of Control Scale, the Neuroticism dimension of Eysenck Personality Questionnaire (EPQ), and Luhtanen & Crocke's Collective Self-esteem Scale. Results indicate that three of the four classic dimensions of core self-evaluation?self-esteem, general self-efficacy and collective self-esteem correlate positively with all three burnout dimensions，whereas neuroticism correlate negatively with all three burnout dimensions. On the other hand, locus of control fail to correlate significantly with any burnout dimensions. In three hierarchical models predicting burnout dimensions, collective self-esteem demonstrats significant increment variances of 2.4%-4.9% beyond four western classic core self-evaluation dimensions.The present study reveales an improtant component of core self-evaluation among Chinese college students:collective self-esteem.

Studies and Application of Memory Source Monitoring

GENG Haiyan,QIAN Dong

2007, 43(5):  716-722. 

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Memory source monitoring has been one of hot topics in memory research in the recent years. The authors review several important issues in this field, including the theoretical framework of memory source monitoring, its implication in studies of eyewitnesses and schizophrenia patients, as well as its neurological mechanism. Further investigations over this issue will provide important experimental evidence for clarifying the nature of memory and the mechanisms of false memory.

Statistical Analysis on the SCI Papers of Peking University in 2005

LIU Xiaopeng,ZHOU Hui

2007, 43(5):  723-727. 

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In 2005, scientists of Peking University, as primary authors, published 2009 SCI papers in 772 kinds of journals, including lots of top journals in different fields. Average impact factor of these papers is 2.03, which is obviously higher than that in 2004. SCI papers of Peking University in 2005 are analyzed, and suggestions are given on current problems and improvement in the future.

Bibliometrics Analysis of Highly Cited Papers Published by Peking University from 1996 to 2006

LI Chunying,REN Chengmei

2007, 43(5):  728-732. 

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The authors collected all the highly cited papers that Peking University published from January 1, 1996 to December 31, 2006 in Essential Science Indicators (ESI). The distribution and the rank of subject, published journals, cited times, corporate authors and published time of the paper were analyzed by bibliometrics. Peking University published 169 highly cited papers which related 17 research fields in ESI, 9 listed in the rank of ESI; Based on the cited times of the paper amount, Peking University rank in 368^th of 3 482 institutions in the world. The results show that the higher citation of the highly cited papers that Peking University published is more related to the quality of these papers ,and also is related to the impact factor of journals, cooperation with worldwide scientists and China's and Peking University's police.

Frictional Collision of Multi-Rigid-Body Systems Based on Energetic Coefficient of Restitution

YAO Wenli,CHEN Bin,XU Jian

2007, 43(5):  585-591. 

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The frictional collision of multi-rigid-body systems is studied. General normal elastic-plastic force-displacement relationship is directly introduced in the calculation of multi-rigid-body systems, and slip-stick and slip?- at the contact point are considered. In existing literatures, the differential method is often used to solve this problem. But due to the much shorter collision time and the much larger force, the choice of calculating step becomes very difficult. Moreover, the non?smoothness of Amontons-Coulomb frictional law leads to the difficulties in finding non?smooth point between sticking and sliding states. Instead of returning to the calculation of differential equation, algebraic method to calculate the states after collision is applied. By the bridge of energetic coefficient of restitution and keeping the traditional approximate assumptions of impact, the dynamic state after the collision can be obtained according to initial conditions before the impact and geometry properties of the system, which energetic coefficient of restitution is calculated as a function of initial conditions based on general normal contact deformation law instead of a material property. The method avoids energy inconsistency and is much more simple.

Wave Propagation in Elastic Square Columns I.Spectrum, Group Velocity Curve and Steady Response

WEI Jianping,SU Xianyue?

2007, 43(5):  592-599. 

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A self-adjoint method is proposed to derive the guided?wave restriction condition. After finding the orthogonal sets corresponding to the guided?wave restriction condition, the analytic dispersive equation, group velocity equation and steady response are obtained simultaneously. It is found that the propagating stress waves are classified by the kinds of the quasi-P, quasi?SV and quasi-SH waves, and are arranged by the standing wave number; the spectrum, the group velocity curve and the steady response have the same regularity. In the end, a calculation is represented, and the spectrum, the group velocity curve and the steady response are plotted of the transversely isotropic square columns.

A New Design for MPEG-4 AVC/H.264 CAVLC Decoding

CUI Xiaoyan,JIANG Anping

2007, 43(5):  664-668. 

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The H.264/AVC video coding standard adopts the Context-based Adaptive Variable Length Code (CAVLC) in order to get high data compression. Because of the large number of code tables and variable code words, the decoding process is very complex.A new design for MPEG-4 AVC/H.264 CAVLC decoding is presented to improve the efficiency of decoding, which is based on the number of zeros (m) followed by the first 1. In the proposed design, the length of the code word and the value of the syntax element can be obtained easily.

Climatic Background of Warm Season Convective Weather in North China Based on the NCEP Analysis

ZHENG Yongguang,ZHANG Chunxi,CHEN Jiong,CHEN Mingxuan,WANG Yingchun

2007, 43(5):  600-608. 

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Due to the demand of nowcasting of convective weather in North China (including Beijing, Tianjin, and Hebei Province), the authors use the averaged fields of NCEP 1°× 1° final analyses during May to August of 2000-2005 to analyze the climatic background of convective weather in warm season in north China. The averaged fields include mean circulation of the lower and upper troposphere, mean humidity, temperature, pseudo?equivalent potential temperature, convective available potential energy (CAPE), convective inhibition (CIN), and so on. The results show that the climatic background in May and June is different to that in July and August. In May and June, cold air mass from north is more active, and North China is mainly influenced by disturbances of westerly wind systems in mid?latitudes, in contrast, in July and August this area is influenced by both disturbances of westerly wind systems in mid?latitudes and disturbances in lower latitudes. There are more hailstorms and thunderstorms in May and June, but more heavy rains in July and August. The mean daily variation of relative humidity of lower troposphere reveals that there is one dry line (dew point front) in the afternoon to the east of Beijing, and the averaged streamlines of 850 hPa indicate that there exists a large?scale convergence line in boundary layer at the north of Beijing. The above results provide nowcasting of convective weather in north China with a climatic background.

Effect of a Magnetic Impurity on the Kondo Splitting of DOS in a Quantum Dot

CHEN Jiang

2007, 43(5):  609-613. 

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Based on the infinite-U Anderson model, Keldysh Green Function was used to calculate the Kondo splitting of DOS (Density of State) in quantum dot induced by a side?coupled magnetic impurity. Because of the normalization for quantum dot energy caused by the ferromagnetic lead, the Kondo peak in DOS splits. It?s shown that the polarization of the magnetic leads and the azimuth of the impurity spin set off the Kondo resonant splitting in the DOS. For the antiparallel configuration of lead magnetization, the localization of the peaks is hardly influenced by the magnetic impurity. For the parallel configuration, three Kondo peaks appear in the DOS and the interval of the peaks depends on the impurity spin azimuth. The splitting in the DOS induced by the magnetic leads can be compensated by the side?coupled impurity, if the polarizations of the magnetic leads are choosed rightly.

Film Fabrication and Electronic Devices of MgB₂ Superconductor

WU Ke,YU Zengqiang,ZHANG Jiedong,NIE Ruijuan,WANG Furen

2007, 43(5):  614-619. 

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The work on fabrication of MgB₂ superconducting thin films via E?Beam evaporation approach is reported. With the Boron film and Mg/B multilayer precursors followed by post?annealing at 900℃ and 750℃ respectively, high quality MgB₂ films have successfully been achieved. Superconducting properties of the samples have been measured and the crystal structure and surface topography have also been characterized. The results showed the performance of these two types of samples was significantly different. Some analyses have been proposed to explain this contrast. Besides, a microwave resonator has been realized based on the superconducting MgB₂ films prepared by this technique.

An Effective Parallel Processing Architecture for Deblocking Filter in H.264

ZHAO Yuexi,JIANG Anping

2007, 43(5):  649-653. 

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An efficient parallel processing method for deblocking filter design in H.264 video coding standard is presented. In order to reduce the memory reference and make the intermediate data reused as soon as possible, an advanced filtering order is taken, and so read/write operation on external memory is executed in parallel with filtering computation. Furthermore, preloading operation is used to reduce complexity of memory structure. As a result, the processing cycles of the proposed architecture with single-port memory architecture is reduced by 9.6%-74.4% compared with the advanced architecture of previous proposals.

Novel Low Power QSBDI Structure for IR ROIC

LIU Dan,LU WengaoCHEN Zhongjian,JI Lijiu,ZHAO Baoying

2007, 43(5):  659-663. 

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A novel low power Quad-Share Buffered Direct-Injection (QSBDI) readout circuit for large format staring ROIC is proposed. In this circuit, four pixels share one common buffer amplifier. With switches' cooperation, the circuit can achieve ITR (integrate then readout) and IWR (integrate while readout) function. With area of 30 μm×30 μm, the capacitor in the pixel is about 0.9 pF and 4.2 pC charge storage capacity, but the power of single pixel is about 500 nW. At the same time, the FPN of the pixel is reduced to order of local mismatch and independent of the format of pixel array. Those characters made QSBDI an outstanding pixel structure for large format 2-D ROIC. An experimental 128×128-pixel ROIC is designed and it will be fabricated with 0.5 μm DPTM n-well CMOS process.

Spatial Pattern of Seasonal Precipitation over the Eastern Part of China

PU Bing,WANG Shaowu,ZHU Jinhong

2007, 43(5):  620-629. 

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Using constructed and observational data of seasonal precipitation in Eastern China (east to 110°E) over 1880-2004, major characters of spatial distribution of precipitation in each season are studied with EOF analysis. Two primary patterns of spatial distribution are found. While precipitation in winter, spring and autumn belong to the first pattern, summer is of the second one. Furthermore, combined with the constructed data of 1880?1950 and observational data of 1951-2004 on 500?hPa geopotential height, the impact of circulation on seasonal precipitation is studied. The results show that the spatial distribution of abnormally seasonal precipitation usually has a close connection with high?level circulations, and the relationship of the two is stable in the past hundred years or more. Finally, research on the periodic variation of spatial structure of seasonal precipitation reflects that every season has interannual and interdecadal variability. The outcome of spectral analysis and wavelets shows that the periods of 2-4 a, 5-8 a, 15 a, 20-25 a and 60 a are the leading cycles of seasonal precipitation in Eastern China.

On the Single-Particle Distribution Function in the Systems of Nanometer Scale:Some Rigorous Results

YONG Hyunchul,YANG　Kaihua,HE Peisong,TIAN　Guangshan

2007, 43(5):  630-638. 

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The properties of the single-particle distribution function in nanometer scale systems are rigorously studied. First, by using the variational principle, it is shown that this function is nonincreasing with respect to the single-particle energy levels at zero temperature. Then, by applying the Klein inequality, the same conclusion can be also established in the case of nonzero temperature. These results show clearly how the behavior of the single-particle distribution function is determined by the stability condition of the systems.

Analysis of the Field Enhancement of Resonant Optical Antennas

YAN Haifeng,YANG Jing,WU Xiaofei,ZHANG Jiasen

2007, 43(5):  639-642. 

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The finite-difference time-domain method is used to calculate the electronic field distribution and enhancement factor of nano-scale optical antennas for different shape, length and substrates. When the resonant wavelength is 915 nm, the antenna with symmetry echelon dipoles has an enhancement factor of 1 739, which is greater than the enhancement factor of 1 076 of the antenna with symmetry rectangle dipoles. The resonant wavelength has a blue-shift when the length of the antenna is decreased. With a glass substrate, the resonant peak of the antenna with a length of the dipole of 80 nm red-shifts from 587?nm to 715 nm and the electric field distribution inclines to the substrate.

Hierarchical Network-on-Chip Design Method

WANG Hongwei,LU Junlin,TONG Dong,CHENG Xu

2007, 43(5):  669-676. 

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With the development of VLSI technology and increasing complexity of System-on-Chip applications, on-chip communication architecture design encounters some problems, such as throughput, power, signal integrity, latency and clock synchronization, Network-on-Chip (NoC) was introduced. With on-chip communication's specific pattern, it is of great significance to design hierarchical Network-on-Chip to improve communication performance and reduce hardware cost. This paper puts forward a hierarchical NoC design method. According to the technology and application requirements, researchers can generate several IP core subsets (“cluster”), and design a NoC architecture as inter-cluster communication requirements. Experiments show with hierarchical NoC design method, this method can improve system performance efficiently, decrease hardware cost, and meet Quality-of-Service requirements at the same time.

The Study of Predictive MAC Protocol in Broadband Satellite Access Network with OBP

LI DouWANG Feng,JI Binghui,XIANG Haige

2007, 43(5):  643-648. 

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The multiple access control (MAC) protocol in broadband satellite access network is investigated. A novel combined dynamic allocation multi-access scheme is proposed, which is based on the chaotic prediction of self-similar traffic. The OPNET simulation system is developed for comparing the performance of different schemes. Simulation results indicate that the novel scheme has better performance when the traffic data exhibit self-similarity. The superiority of centralized access control with satellite onboard processing (OBP) is also proved.

A Low Complexity H.264 VBSME Architecture for Wireless Video Communication Applications

PENG Chungan,YU Dunshan,CAO Xixin,SHENG Shimin

2007, 43(5):  654-658. 

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An efficient low complexity H.264 VBSME (variable-block-size motion estimation) VLSI (very large scale integrated) architecture is designed, in which a MB-size input buffer, 17×16 snake scan register array, 8×8 PE array,4×4 SAD-adder-tree are used and a four-step VBS MV generator structure is proposed to reduce the hardware cost for wireless video communication applications. Compared with the MB-level VBSME structure, the total count of gates is reduced to 37%, the delay of critical path is shorten from 9.8 ns to 8.2 ns, and nearly 50.3% power is saved and the main data-path width is narrowed to 25%, but all MB characters are reserved. Its low-hardware-complexity performance makes it suitable for the integration of H.264 encoder in wireless video communication applications.

A Current Source in ROIC with Working Temperature of 77 K

TANG Ju,LU Wengao,CHEN Zhongjian,JI Lijiu,ZHANG Xing

2007, 43(5):  677-682. 

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This paper gives a programmable current source in Readout-Integrated Circuit (ROIC) that is working in liquid nitrogen (77 K) without outside component. The design adopts MOS transistor working at sub-threshold region to enhance robust of circuit. The design uses 0.5 μm standard CMOS process with supply voltage of 5 V. From measurement result, In room temperature, output current varies from 199 nA to 212 nA with supply voltage variation from 2.3 V to 6.4 V, the precision is about 1.4%/V; In liquid nitrogen circumstance, output current varies from 355 nA to 372 nA with supply voltage variation from 3 V to 6.8 V, the precision is about 1.3%/V. As working temperature is stable, the current source's stability over temperature is not of importance.

Simulated Study on the Photonic Band Gap of One-Dimensional ZnO/ MgF₂ Photonic Crystal

ZHU Kongtao,ZHANG QifengWU Jinlei

2007, 43(5):  683-686. 

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Photonic band gap (PBG) of one-dimensional ZnO/MgF₂ photonic crystal is studied with the optical transmission matrix method. A one-dimensional model consisting of ZnO and MgF₂ is proposed. The influence of PBG by the periodicity N is studied, and the effect of the PBG width and the center length by the film thickness is also discussed. In the end, the authors discuss the condition to get the maximum of the PBG width with the center length as a constant, and propose an explanation from physics mechanism. When the products of the refractive index and the thickness of the two different films are equal, the PBG reaches the maximum. When the product is 93 nm, the center length is at 385.05 nm with the PBG width of 138.7 nm.

Semiconductor Device Model Parameter Extraction Based on Genetic Algorithm

WU Tao,DU Gang,LIU XiaoyanHAN Ruqi

2007, 43(5):  687-693. 

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With the dimension of the semiconductor device scaling down, the model of the devices becoming more and more complex, the number of the model parameters also increasing, traditional gradient-based parameter extraction methods have more and more difficulty to deal with the models which have hundreds of parameters. Genetic algorithm based parameter extraction methods attracte tremendous attention since they can overcome the difficulty of traditional methods. Here the theory of genetic algorithm based parameter extraction method is illustrated, and the defects and some improvements are also put forward.

Power-Aware Gated Clock Routing with Merging Cost Backward Annotation Using Simulated Annealing Method

DUAN Lian,XU Hu,WANG Kui,CHENG Xu

2007, 43(5):  694-702. 

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Traditional clock routing algorithms can be extended to embrace clock gating by merging minimum switching capacitance node pairs in the bottom-up phase. However, optimizing switching capacitance in the current merging nodes will affect their ancestors' gating chances, which may deteriorate the power consumption. A zero-skew gated clock routing algorithm is proposed to solve this problem. It can reduce the total switching capacitance by evaluating the merging cost of this effect using the result derived from the clock tree generated in the last round. As the result needs to be optimized in iterations, this algorithm employs a simulated annealing technique. At each iteration, the clock tree reconstructs using back-annotated merging cost information and new constraints are generated for optimization in the next round. Experiment results show that this algorithm can achieve up to 23% power reduction compared to the traditional Greedy-DME algorithm.

A Semi-Centralized Computing Model for Network Computer Systems

YANG Chun,XIA Yubin,NIU Yan,CHENG Xu

2007, 43(5):  703-708. 

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A semi-centralized computing model is proposed for network computer systems, which enables clients to participate more computing workloads and to provide seamless operating experience for users while all management advantages of traditional network computer systems are preserved. The authors investigates the strategies for computing partition, input integration and display integration, and implements a prototype of video player based on the semi-centralized computing model. Experimental results show that it can provide seamless video playback and reduce server load dramatically.