Table of Content

20 May 2002, Volume 38 Issue 3

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A Novel Charge Pump in PLL

LIN Yijing,SHENG Shimin

2002, 38(3):  384-386. 

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The error generated by Charge Pump in PLL is analized and a novel circuit is proposed. The proposed circuit and proposes a novel circuit that eliminates overshoot injection current and gets much better error characteristic than traditional Charge Pump. Hspice simulation results (using BSIM3V3 model) are showed and compared to traditional ones.

Stroop Effect under Divided vs. Focused Attention: the Influence of Consciousness

GENG Haiyan,LI Yunfeng

2002, 38(3):  421-426. 

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Qualitative differences in performance were established across perception with awareness and perception without awareness, based on one phenomenon: Stroop priming. A typical Stroop effect occurred when color words were perceived without awareness, whereas a reversed Stroop effect occurred when color words were perceived with awareness. A stimulus that was perceived without awareness under a divided-attention condition, could be perceived with awareness either by focusing attention or by increasing stimulus quality.

Chinese Wall Policy and Its Extension in Multilevel Security System

QIN Chao,CHEN Zhong,DUAN Yunsuo

2002, 38(3):  369-374. 

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The Chinese Wall security policy is an excellent example of a commercial nondisclosure policy. To extend Chinese Wall policy in multilevel security environment, authors use lattice to label data, and propose an improving policy in term of aggregate system. Moreover, authors present a scheme using a database based history access and linklist of aggregate dataset of interest conflict.

The Model of Distributed GIS-oriented Multi-agent System

LUO Yingwei,WANG Xiaolin,XU Zhuoqun

2002, 38(3):  375-383. 

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Agent technology is applied into constructing distributed GIS. Firstly, the classification and structure of agent in distributed GIS are analyzed; then the model of distributed GIS-oriented multi-agent system named as Geo-Agents is designed and implemented, including its communication mode, architecture and distributed mode; at last, the uses of Geo-Agents are explored: agent-based spatial information navigation and spatial decision-support system.

Study for the Negative Parity Energy Spectrum of Ba and Xe Isotopes Nuclei with Effective Three-body Potential

LIU Yingtai

2002, 38(3):  323-328. 

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Within the O(6) limit of s-d IBM1, the effective three-body potential between the interactions of d-bosons is introduced with the consideration of octupole states, which are produced by a f-boson plus (N-1) s-d. Then the analytic expressions of negative parity energy spectrum formula is obtained. Also the negative parity energy spectra of even-even nuclei ^{118, 120}Xe and ^{124, 126, 128, 130}Ba are calculated. The good fits with the experimental data are obtained, and Staggering phenomena is quantitatively analyzed with Staggering index formula in negative parity energy spectra.

The Application of Magnetodynamic Resonance in Magnetostrictive Weak Magnetic Fiber Optic Sensor

LI Shourong,YAO Shouquan

2002, 38(3):  329-333. 

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It is included that the factors which affect the resonance frequency and how to reduce the affection, so that the magnetostrictive weak magnetic fiber optic sensor has a high sensitivity and good stability.

Generalized Regular Variation Function and Its Inverse Function

WANG Xiaoqian,CHENG Shihong

2002, 38(3):  303-311. 

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The behavior of the generalized regular variation functions is studied. The properties of the Π and Γ variation functions are generalized to the generalized regular variation functions and their inverse functions-Γ(γ, b) functions. Γ(γ, b) functions' basic properties, expression theorem and equivalent conditions are proved. The domains of the extreme value distributions and rates of the convergence of the Von. Mises' condition are discussed.

A New Family of Divisible Difference Sets

DENG Yingpu

2002, 38(3):  312-314. 

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It is given that an another proof for the classical affine relative difference set by using Gauss sums, and we construct a new family of divisible difference sets with parameters ((qⁿ-1)/(q-1), q-1, q^(n-1)-1, q^(n-1)-1, q^(n-2)-1), where n≥2, q is a power of a prime.

A New Way of Constructing Hadamard Difference Sets

XIONG Guohua

2002, 38(3):  315-317. 

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Provide a new way of constructing Hadamard difference sets (HDS) with parameters (4q², q(2q-1), q(q-1)) by a special nonlinear function on a ring.

Orthogonal Bent Functions and High Nonlinearity Balanced Functions Satisfying SAC

WANG Zhangxiong

2002, 38(3):  318-322. 

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It is constructed that a class of orthogonal Bent sequences, and used them to get balanced functions with high nonlinearity and satisfying SAC. The results are more extending.

The Research of the Effects of the Atmosphere to the Ultraviolet Radiation

GUO Shichang,QIN Yu,ZHAO Bolin,WU Jian,CHENG Hui,CHENG Yan,QIN Fang

2002, 38(3):  334-341. 

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A two stream model has been used to calculate the variation of optical depth and their effects to ultraviolet radiation of each extinction material. With the model, the relation among season, solar zenith angle and ultraviolet radiation has been discussed, and the variation of ultraviolet radiation under different clouds has also been studied. The comparative research of ultraviolet radiation among Kunming, Beijing and other abroad area at the same latitude has also been done.

Radar Rainfall Estimation and Its Application on Runoff Simulation over SHIGUANHE Catchments

LIU Xiaoyang,MAO Jietai,ZHU Yuanjing,LI Jiren

2002, 38(3):  342-349. 

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The optimum interpolation method is used to estimate radar measured rainfall which then be applied to TOPMODEL to simulate discharge of SHIGUANHE catchment during the summer of 1998 in GAME/HUBEX project. Comparison of simulated discharges between radar and rain gauge implements over a 1500-hour series. The results indicate that: (1) Only with a few rain gauges to adjust the radar estimated rainfall, authors could simulate the runoff as good as that from rain-gauge-network-measured rainfall; (2) The accuracy of radar rainfall estimation to heavy rain acts as a more important role than that of light rain; (3) The estimation error of amount precipitation over a period can be treated as an index for runoff simulation ability.

The Spatio-Temporal Evolvement of Pacific SSTA

WANG Zaiwen,LI Xiaodong

2002, 38(3):  350-357. 

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With the Rotational Complex Empirical Orthogonal Function (RCEOF), we analyzed the spatio-temporal Evolvement of the latest fifty years SSTA of Pacific Ocean. Came to a result that there are two strong signal center: One at middle and east Pacific Ocean near equator, the other at 40°N. It will take several months to half a year for the signal to reach West Pacific Ocean from east coast of Pacific Ocean near equator (correspond to ENSO). Most cycles of SSTA are in three to ten years, and there are annual and biyearly cycles too.

The Numerical Simulation of Typhoon Cloud

ZHU Peijun,CHEN Min,TAO Zuyu,WANG Hongqing

2002, 38(3):  358-363. 

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The simulative cloud image, made from the mixing ratios of cloud liquid water, rain water, ice crystal, snow, graupel which were outputted by the Mesoscale Model MM5, resemble the GMS satellite infrared image very well and also show the cloud evolution of typhoon Winnie from tropical cyclone to extratropical cyclone after landing. The simulated image, which provide the three-dimensional distribution of water contents of cloud, can make up the insufficiency of satellite observation which can only examine the top of cloud.

Study of Al Nanoparticles on Au Substrate with Scanning Capacitance Microscopy

LIU Saijin,HOU Shimin,SHEN Ziyong,ZHANG Qifeng,GUO Dengzhu,XUE Zengquan

2002, 38(3):  364-368. 

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The theory of lift-mode scan capacitance microscope(LM-SCM)is analyzed. Under the hypothesis of small amplitude, it is found that the oscillation amplitude of the cantilever is directly proportional to the gradient of the surface capacitance. The surface morphology and capacitance of aluminum nanoparticles were studied with LM-SCM. The relationship between the contrast of the capacitance image and the lift height of the cantilever was analyzed and proved in experiments.

Flow Patterns of Lower Atmosphere over Beijing Area

CAI Xuhui,GUO Yu,LIU Huizhi,CHEN Jiayi

2002, 38(3):  387-392. 

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Wind-field diagnostic analysis and historical observation data are used to reveal general flow patterns of lower atmosphere over Beijing area. The preliminary results show that air flows in this area could be classified into autumn-winter pattern and spring-summer pattern. The former is under effect of more strong synoptic systems, while the latter shows more characteristics of mesoscale thermal circulation induced by topography. The mesoscale circulation determines basic air flow patterns in this area, which is typical in spring-summer season and in calm weather of autumn-winter season. Air flow under strong wind condition in autumn-winter season is seriously perturbed by topography. The perturbation displays as a horizontal vortex covering whole city of Beijing and part of mountain area in northwest.

A Study of the Spatial Distribution Characteristics of Human Landscape Impact in Wolong National Natural Reserve, Sichuan Province

KONG Ningning,ZENG Hui,LI Shujuan

2002, 38(3):  393-399. 

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Based on the landscape remote sensing mapping, buffer zone analysis and total variation index calculation of landscape structure for two neighbored buffer zones were used to divide the natural landscape and human impacted landscape in Wolong Natural Reserve. The spatial distribution characteristics of human impacted landscape were also studied. The results indicated that hydraulic power station, residential area, and road are three primary human impact sources, and the distance of significant impact on landscape structure of around area for these sources is between 1000～1200m. This distance can be used to divide the whole study area into natural landscape and human impact landscape suitably. Human landscape distribution to land form resulted that the area with elevation from 2400 to 4800m and slope gradient from 20°to 40°are the heaviest human impacted region in Wolong Natural Reserve. The spatial distribution characteristics of human impacted landscape are very dangerous for the natural conservation management works. Furthermore, it is also concluded that suitable dividing of natural and human impacted landscape may help the detailed study of landscape human impact.

The Identification of Pearls without Damage

GAN Yixuan,CUI Wenyuan

2002, 38(3):  400-403. 

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This article introduces the conventional way of identifying the pearls. A nondestructive identifying way is also showed by means of FT-IR. The appearance of the apex in 1472cm^-1 and the changes of the apexes involved with protein in FT-IR are the keys of identification for pearls.

A Repetition Priming Paradigm in Monkey and Its Training Process

QIN Suli,SHEN Zheng

2002, 38(3):  404-412. 

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Repetition priming paradigm in two rhesus monkeys was set up using three categories of stimuli (face, figure, food) in present study. The present study suggested that the features of this paradigm are as follows: 1. three sequential steps (concurrent discrimination, successive discrimination and repetition priming paradigm) are included; 2. It is effective to set up a repetition-priming paradigm that human and animal can share in order to explore the relativity between phenomena of repetition suppression observed in animals and priming phenomena; 3. learning time of repetition priming paradigm in monkey is category-dependent. This study discussed the influencing factors and importance of setting up the priming paradigm in monkey.

Achievement Motives, Risk-taking and Locus of Control

XIE Xiaofei

2002, 38(3):  413-420. 

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The variables of the locus of control on individuals were defined in terms of internal-control and external-control. Based on these two dimensions, it analyzed the connections among the locus of control, the achievement motives and the risk-taking. The data supported the conclusion that there existed explicit relationships among the three kinds of variables. Despite the fact that both achievement motives and risk-taking tendency were notably related to the locus of control, the extent and the way of the correlation varied to some extent. There were mutual casualties between the two dimensions of the locus of control and the two tendencies of the achievement motives; moreover, from both the internal and the external dimensions, one might distinguish in individuals the two tendencies of seeking success and averting failure. As to the risk-taking, certain correlation could also be observed between the locus of control and the risk-taking; yet, the correlation was comparatively much weaker. The risk-taking tendency only displayed some internal-control characteristics, while the external-control dimension told nothing about it.

Research on Dependence of Resistivity Changing Feature on Axial Load under Elastic Constraint with Experiment

CHEN Feng,AN Jinzhen,LIAO Chunting

2002, 38(3):  427-430. 

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Four arrays of apparent resistivity are arranged at this measuring surface of granite sample symmetrically with symmetrical four-electrode method, and at an angle of 45°between any two adjacent arrays. The elastic constraint is exerted on 4 surfaces for parallel to the longest dimension of the sample. The samples are compressed along the direction parallel to the longest dimension of the cubic, and the variation of apparent resistivity during the whole loading process is observed. The experimental results are the following: 1) the resistivity changing features of rock show rise-smooth-drop, and the smooth segment is very short and unobvious. 2) the time of first drop for the apparent resistivity is earlier than all other loading experimental results, the rupture stress about moves up by 10 per cent. Viz: the apparent resistivity starting drop when axial rupture stress increases about 40 per cent for the array parallel to the axial; the apparent resistivity starting drop when axial rupture stress reaches about one-third for the arrays non-parallel to the axial. 3) the speed of resistivity drop gradually increases since the resistivity starting drop, but increase is quite slow, and the resistivity change amplitude which is caused by the unit axial stress variety is not very large before the rock big rupture.

A Review on Petrologic Evidences for Mesozoic Lithosphere Delamination in East Qinling-Dabie Mountains

LI Chao,CHEN Yanjing

2002, 38(3):  431-441. 

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Lithosphere delamination is an important way for compositional and structural evolution of collisional orogens. Geotectonic research, geophysical survey and geochemical analysis have revealed that the lithosphere of East Qinling-Dabie Mountains had delaminated intensively in Mesozoic. However, the extensive Mesozoic metamorphism and magmatism have been weakly related to lithosphere delamination. Based on a comprehensive review on research results of metamorphic rocks, the authors argue that the formation and exhumation of UHPM (ultra-high pressure metamorphite) experienced two stages, i.e., cold slab subduction and exhumation during 240～200Ma, and lithosphere delamination and thermal exhumation during 196～163Ma. The rapid thermal exhumation, co-occurred with extensive regional metamorphism and intermediate-acidic magmatism, implied that the subducted slabs had broken off and delaminated. The p-T-t path of UHPM consists of two curves, i.e., a barrette-like curve reflecting the process of cold slab subduction and exhumation (cold overthrusting), and a crescent curve representing the thermal exhumation after slab breakoff. By statistically analyzing of isotopic ages for granitoids and commenting on previous studies, the authors preliminarily determine that a large volume of granitoids developed during 200～100Ma, predominately formed in the period of 150～100Ma, with the peak age at about 130Ma. The inferred lithosphere delamination from the development of granitoids occurred slightly later than that deduced from researches on metamorphic rocks. Distant effect of Jurassic collisions of Qiangtang terrane, Lasa terrane and Paleo-Pacific land onto the Eurasian land made East Qinling-Dabie Mountains in a compressional circumstance for a long time, and suppressed its orogenic extension; whereas, Cretaceous late-collisional extension and appearance of West Pacific trench-arc-basin system relieved East Qinling-Dabie Mountains of external compression, instantly result in violent orogenic lithosphere delamination-extension and depressurized-calefactive melting, and consequently, led to the formation of large scale Early Cretaceous granitoids and intermediate-acidic volcanic rocks. In conclusion the magmatism caused by lithosphere delamination in East Qinling-Dabie Mountains occurred in the transition from compression to extension in the period of J₃-K₂.

On the State Science & Technology Awards Acquired by Peking University

ZHOU Hui,WANG Jin,ZHU Xing,LIU Bo

2002, 38(3):  442-446. 

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State Science and Technology Awards has been one of the important indexes of an institution or individual's academic status and social contribution, with its high visibility, deep impact and extensive modality. A world-class university should not only provide exceptional education, but also achieve top research reputation. Peking University, as the first contributor, has obtained one State Preeminent Science and Technology Award and sixteen State Natural Science Awards, leading the universities of our nation with the unparalleled contribution in fundamental research. On the other hand, the university's achievement in State Technological Innovation Award and State Scientific and Technological Progress Award is much less impressive. It is suggested that long-term, stable supports should go to those achieved and solid research groups to produce more significant fruits.Creating a generous environment for those talented researchers is essential to the construction of a world-class university.