Table of Content

20 January 2002, Volume 38 Issue 1

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An Embedded Wavelet Quadtree Interframe Coding Algorithm

WANG Minghui,PENG Lizhong

2002, 38(1):  1-7. 

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Motion compensated prediction (MCP) error image has significant amplitudes mainly along the boundaries of moving objects, correspondingly its wavelet coefficients contain large energy in high frequency bands. This greatly reduces the coding efficiency of EZW. It is first provided that the correspondence between the significant amplitudes area of the MCP error image and the wavelet coefficient significant map, then encode the significant map efficiently using quadtree approach, followed by bit-plane coding the significant coefficients to produce an embedded data stream. Experiment result shows that compared to EZW and ZTE, the proposed algorithm is more efficient and has better performance.

Another Proof for A Combinatorial Lemma of Liao

ZHANG Yong

2002, 38(1):  8-10. 

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It is given a geometrical proof of an essential combinatorial lemma of Liao.

Oscillation on Neutral Differential Equations with Positive and Negative Coefficients

ZHANG Xiaosheng,WANG Duo

2002, 38(1):  11-17. 

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Sufficient conditions for the oscillation of the equation d/dt[x(t)-R(t)x(t-r)]+P(t)x(t-τ)-Q(t)x(t-δ)=0 are obtained whereR(t)+∫^t _t-τ+δQ(u)du-1 is allowed to oscillates and the condition ∫^∞_t0s[P(s)-Q(s-τ+δ)]∫^∞_s[P(u)-Q(u-τ+δ)]duds=∞ is not necessary.

Numerical Simulation and Experimental Investigation on Vibration Control of A Rotating Flexible Beam

ZHU Farong,HUANG Qinghua,CHEN Decheng

2002, 38(1):  24-29. 

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Compared with the rigid-flexible coupling dynamic models that had been constructed in other published papers, comprehension about the equation of rotating flexible beam based on the method of small element is presented, and some fuzzy understanding are clarified.Numerical simulations on the vibration control of rotating flexible beam with positive position feedback are carried out. More over, using piezoelectric ceramic as sensors and actuators, several experiments are performed, their results are shown and discussed.

Experimental Studies on the Non-linear Development of the Instability in the Natural Convection Boundary Layer

YAN Dachun,ZHANG Hanxun

2002, 38(1):  18-23. 

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The instability in the natural convection boundary layer initiates with the buoyancy eigenmode and develops into non-linear stage with the turbulization of the buoyancy eigenmode. In the mean time, the invisid eigenmode at the inflexion point appears and begins to increase at the outer layer. Experimental results show that the turbulent layer near the maximum velocity point can be detected while the reformed Grashof number G＞100 and after the buoyancy eigenmode crashes down; when G＞170, the invisid eigenmode becomes turbulent and the viscous eigenmode in the high shear layer near the wall appears. All of these characterize the growth and decaying of the instability waves in the natural convection boundary layer with spatial mode.

The Equalibrium Points of Control Systems with Single Saturate Input under Commuting Matrices

GUO Shuli,HUANG Lin,CHU Tianguang

2002, 38(1):  30-34. 

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The equilibrium points of control systems with saturated inputs are defined. Based on these definitions, all kinds of the equilibrium points are analyzed in control systems with single saturated input. By the above facts, it is necessary in analyzing globally asymptotical stability of the origin that the other asymptotical stability equilibrium points are false ones.

Control and Audit Based on Users under Unix

LI Jun,LI Haitao,WANG Bo

2002, 38(1):  35-38. 

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In Unix system,it is necessary to add module of control and audit based on users. By adding a net module called iplog in Solaris, the goal is fulfilled and therefore the safety of operation system is strengthened. It is shown that the method is effective solution with not very heavy load.

RFQ Electrode Parameter Calculation and Machining Program-RFQPOLE

YAN Xueqing,LU Yuanrong,WU Yu,ZHANG Honglin,GAO Shuli,FANG Jiaxun

2002, 38(1):  39-43. 

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The program RFQPOLE is described, which could be used in the design and machining for Mini-vane RFQ electrode. The results from PARMTEQ, a dynamic calculation program, are directly used by RFQPOLE. It can display the track of the milling cutter in the process of machining after the electrode parameters along the axis are determined by quasi-sine approximation. It shows the visual pictures of electrodes at last. The 1MeV 26MHz O⁺ RFQ at Peking University is given as an example in electrode design.

Study on the Energy Spectra of sdg Odd-A Nuclei ^115～123I
with PDHF Method

LIU Yingtai,LIAO Jizhi

2002, 38(1):  44-48. 

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The approximate angular-momentum-projected Hartree-Fock(PDHF) method is used to study some odd-A nuclei in the 3s-2d-1g shell: ^115～123I. Their ground bands and low excited bands are calculated. The calculated results agree well with the experimental spectrum.

Analog Phase Shifter

LU Yuanrong,W Gutowski

2002, 38(1):  49-56. 

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It is presented that the theory and the manufacturing technology of such analog phase shifter, which are made from conventional 3dB quadrature hybrids coupler with two identical varactor-diode networks to provide a shifted phase that varies continuously with biased DC voltage. Several analog phase shifters have been made for different operating frequencies. Each phase shifter has phase range more than 180°, return loss better than-20dB, insertion loss 4.8dB(including 3dB attenuator), transmission difference less than±0.075 dB.Computer code PHASES. bas can present the referenced component values.

Design and Proof-of-concept, Experimental Demonstration of IP Wavelength Router

WANG Yong,YIN Hongxi,XU Anshi,WU Deming

2002, 38(1):  57-62. 

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A novel method, called DPDP(default path and dedicated path)is introduced and an experiment is carried out to demonstrate the possibilities and rationality of node design, working process and corresponding communication protocol implemented by DPDP. The problems related with DPDP are also discussed at last.

Simulating Threshold Voltage Shift of MOS Devices Due to Radiation in the Low-dose Range

WAN Xinheng,ZHANG Xing,GAO Wenyu,HUANG Ru,WANG Yangyuan

2002, 38(1):  63-68. 

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An analytical MOSFET threshold voltage shift model due to radiation in the low-dose range has been developed for circuit simulations. Experimental data in the literature shows that the model predictions are in good agreement. It is simple in functional form and hence computationally efficient. It can be used as a basic circuit simulation tool for analysing MOSFET exposed to a nuclear environment up to about 1Mrad(Si). In accordance with common believe, radiation induced absolute change of threshold voltage was found to be larger in irradiated PMOS devices. However, if the radiation sensitivity is defined in the way we did it, the results indicated NMOS rather than PMOS devices are more sensitive, especially at low doses. This is important from the standpoint of their possible application in dosimetry.

Fast Selection Method for SERM Factorizations of Linear Transforms

WEI Changjiang,HAO Pengwei,SHI Qingyun

2002, 38(1):  69-76. 

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A selection method of SERM factorizations for linear transforms is presented. It is discovered that the near optimal results are almost everywhere and when the factorization error is small, the closer the permutation matrices, the closer the results. According this fact, A local search is proposed that based near optimal factorization method which can obtain the near optimal results. Moreover, this method convergence very fast, can usually obtain useful results by very limited iterations.It is tested lossless image coding with the selection results and good results is obtained.

Prediction and Its Verification of Strong El Nino Event in 1997

WEI Songlin

2002, 38(1):  77-82. 

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The ENI of El Nino events is expressed by using differences of Sea Surface Temperature (SST) in the area of equatorial east Pacific (0～10°S, 90～180°W). Based on ENI's definition, 25 El Nino events and 26 La Nina events from 1870 to 2000 are defined. And the starting and ending time of 1997's strong El Nino event is predicted six months ahead of the event by using ENI's Three Periodical Overlapping Prediction method. The prediction offers great support to the accurate prediction of the flush flood occurred along Nenjiang river in 1998.

Multimode and Its Application in Climate Analysis

WANG Lei,KANG Dujuan,LI Xiaodong

2002, 38(1):  83-89. 

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The probability distributions of climatic elements are discussed. Based on the characters of them, a multimode model is introduced and verified through the nonlinear fitting. The climate features of quasi-biennial oscillation of the stratospheric zonal wind over equator, the ENSO Index, the surface pressure at Reykjavik(21.90°W 64.13°N)and Swedish temperature, and the Northern Hemisphere tree ring all show that the multimode are universal in the climatic system.

Numerical Simulation of Atmospheric Boundary-layer Structure over Urban and Rural Areas

LIU Shuhua,LI Jie,WEN Pinghui

2002, 38(1):  90-97. 

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A transfer model is established, which can be used to study the interaction between the land surface physical processes of inhomogeneous region and the structure of atmosphere boundary-layer over urban and rural terrains. The model has simulated surface heat flux, surface temperature, temperature profiles, height of mixture layer and so on. And the differences between urban area, suburban area and rural area have been compared. This model mainly depends on the parameters below: surface albedo, surface roughness coefficient, moisture available coefficient of soil, thermal capacity and thermal diffusion coefficient of errain,cloudage. The result shows that this model can simulate the structure and eigenvalues of atmosphere boundary layer and their changes in a day. Parameters used in this model aim at Beijing City, and the time is at the beginning of September. To other cities, or other time, the parameters should be adjusted accordingly. In addition, being adjusted, the model can also be used for other homogeneous and inhomogeneous terrains.

The Choice of Scanning Direction of Multi-angle Thermal Infrared Remote Sensing

XU Xiru,CHEN Liangfu

2002, 38(1):  98-103. 

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The tradition of crop farming is crop sown in line. How its directional character of thermal radiance affected by crop height(H), width of swath(W)and the distance between swath(D)which characterize its geometrical construction had been answered by this paper through Monte Carlo simulation. When the direction of scanning is vertical to crop line(φ=90°), the correlation coefficient among multi-angle thermal radiance values is the lowest. It is favorable to retrieve T_v and T_s with high accuracy. When the direction of scanning coincide with crop line(φ=0°), the correlation coefficient it the highest and also sensitive to the change of azimuth angle. It is unfavorable to retrieve T_v and T_s with certain accuracy.

The Formation Mechanism of Ground Fissure in Datong City

LI Shude,YUAN Renmao

2002, 38(1):  104-108. 

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Recently, 9 ground fissures have occurred in Datong City with 30.8km length altogether. The ground fissures spread out in the direction of NE-SW or NEE-SWW. According to the study of ground fissures distributions and characters, the authors found the reason that why the ground fissures show up. Because of the press come from the Plate of Tibet and Pacific, there are lots of the right-rotating faults and Earth Mantle Hunching in Datong Basin. Those made the crust of Datong Basin thin and the rock fault extended to the upper Mantle, so the earthquake and ground fissures occurred along with the fault depression in Datong Basin.

Self-Adaptive WebGIS Pattern

CHENG Chengqi,HU Xuelian

2002, 38(1):  115-120. 

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To implement distributed application component and data storage and access on Internet is a keystone in WebGIS research. Based on the concept of metadata, this paper analyzed the disadvantage of present WebGIS architecture, extended the concept of metadata, brought forward program metadata, and provided a flexible configuration mode of GIS components, preferably solved the problem of sharing distributed data and configuring application flexibly.

Sediments and Structural Features of Nangqian Tertiary Basin in Eastern of Tibet-Qingzang Plateau

WANG Shifeng,YI Haisheng,WANG Chengshan

2002, 38(1):  109-114. 

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Nangqian basin locates at the eastern Tibet-Qingzang plateau, which is in low study level at present because of its grim environment. The authors describe in details about its features such as topography, petrologic features, deposition system, palaeo-flow direction etc. Moreover, authors point out the basin developed in strike-apart tectonic environment,and the sediment is close to provenance and quickly accumulated. All evidence disclose the development of the basin and the activity of Zhaqu Fault which controls the basin development.

The Serial Position Effects in the Continuous Distractor Paradigm

WU Yanhong,ZHU Ying

2002, 38(1):  121-126. 

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The robust serial position effects were founded in the free recall experiment and in the continuous distractor paradigm with Chinese character. But in the 30s distractor experiment paradigm, the primacy effect still exited, the recency effect disappeared. And the contextual-retrieval hypothesis failed to explain this phenomenon. According to the contextual cue and memory trace, it is applied successfully that the associative memory and absolute memory to the primacy effect and the recency effect respectively.

Measure and Analysis on Managers' Individual Influence

XIE Xiaofei,CHEN Wenfeng

2002, 38(1):  127-135. 

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A questionnaire of "Individual Influence of Managers" was formed through collecting items, designing and conducting a initial questionnaire, and examining the structure validity of the questionnaire. The items were filtrated according to three evaluation criteria. Three sub-scales manifested individual personality scale 5.8(SD=0.4895)>power and norm 5.1(SD=0.6223)>interrelationship 4.7(SD=0.6189). It showed that managers' influence upon their subordinates mainly depended on their individual charm and personality and their effort to establish an informal authority, which was indeed an effective and recommendable way in enhancing one's influence in an organization. The managers could be divided into two groups, who showed significant variations on the three sub-scale variables of power, relationship and personality. Concerning these three variables, groups of high and low scores obviously differ from one another. The low-score group probably remained on a relatively lower level with regard to their way of influencing their subordinates. Improvement through some training was therefore needed. This study offered an effective tool for the training of managers' individual influences.

Effects of Divided Attention on Encoding and Retrieval Processes in Short-term Memory

BAO Yan

2002, 38(1):  136-141. 

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College students were tested to investigate attentional resources demanded by encoding and retrieval processes in short term memory with a divided attention paradigm. Tone monitoring task was used as a secondary task during encoding, retrieval or both. Results of free recall and serial recall experiments consistently showed that memory performance was significantly impaired while divided attention at encoding, but unaffected while divided attention at retrieval, compared wtih that of full attention condition. The data suggested that encoding processes of short-term memory demand relatively large attentional resources, while retrieval processes in short-term memory demand little of them.

Bi-directional Activation of Neural Representation in Vision: Bottom-up and Top-down Activation
--Experimental Evidences from Human and Monkey

QIN Suli,SHEN Zheng

2002, 38(1):  142-148. 

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Bottom-up processing and feature detecting theory based on strong electrophysiological evidences has played a dominant role in the visual research for long time. People know top-down processing just by common sense. Knowledge or experience are recalled from memory by reactivation of their neural representations and affected visual processes. However recently, researches from human and monkey provide experimental evidences for top-down processing. First, mnemonic representation of visual objects and faces, located in the ventral processing stream of visual perception in monkey, provide the best evidences of how neuronal codes are created by neurons that have the special ability to link the representations of temporally associated stimuli; second, experiments suggest that not only bottom-up signals from the retina but also top-down signals from the prefrontal cortex can trigger the retrieval of associative codes, which may serve as a neural basis both for the conscious recall and for the visual processes affected by top-down processing Further studies will improve people's understanding of the causal relation of activation and behavior by use of combined fMRI and electrophysiology or lesion studies.