Journal of University of Chinese Academy of Sciences

Effects of Glucocorticoids on Memory Consolidation and Retrieval

YANG Hong-Yu, LIN Wen-Juan

2006, 23 (1): 1-3. DOI: 10.7523/j.issn.2095-6134.2006.1.002

Posttraining activation of glucocorticoid pathways usually enhances memory consolidation. The effects of glucocorticoid on memory consolidation, however, follow up an inverted-shape dose-response relationship. High circulating level of glucocorticoids may impair memory retrieval processes by influences on the hippocampus. Glucocorticoid influences on memory consolidation depend on basolateral complex of the amygdala and interactions with other brain regions. These apparently dual effects of glucocorticoids on memory consolidation and memory retrieval might be related.

Analysis of the Involutive Characteristic Set Method for Algebraic PDE Systems

MENG Xiao-Hui，CHEN Yu-Fu

2006, 23 (1): 7-22. DOI: 10.7523/j.issn.2095-6134.2006.1.004

Abstract ( 1152 ) PDF (KB) ( 0 )

Based onWu-Ritt’s characteristic set method and V. Gerdet’s involutive division method,
we defined the involutive characteristic set (abbr. ICS) for a set of non-linear PDEs with
respect to a general involutive direction. The ICS method depends on two factors: the prolongation
direction and the variable ordering. In this paper, we report an implementation
of the ICS method and use it to solve a large set of PDE systems raised from the computation
of symmetric groups for PDEs. Based on the experiments, we try to select the best
prolongation direction and the variable ordering for the ICS algorithm.

A Chinese Sentence Generator Based on Hybrid-Template for Spoken Dialogue System

FANG Zhi-Wei, DU Li-Min, YU Shui-Yuan

2006, 23 (1): 23-30. DOI: 10.7523/j.issn.2095-6134.2006.1.005

Abstract ( 1370 ) PDF (KB) ( 0 )

Based on phrase-standard grammar system, we plan out a hybrid-template method to realize the language generator of Chinese spoken dialogue system. In this hybrid-template method: phrase templates are defined to generate phrases; sentence templates are defined to generate fundamental positive declarative sentences; and transform rules of sentence pattern are defined to generate other sentence patterns, such as negative pattern and interrogative pattern. A subjective assessment result indicates the generator possesses a high portability and a comparatively satisfying efficiency of language generation. Therefore we think our generator of hybrid-template is feasible of generating Chinese simple sentence.

Establishment of Qualitative and Quantitative Models for Affinity Chromatography-Based High-Throughput Screening

LIU Bai-Ling, LI Song-Jun

2006, 23 (1): 31-38. DOI: 10.7523/j.issn.2095-6134.2006.1.006

Abstract ( 1605 ) PDF (KB) ( 0 )

Affinity chromatography (AC) technique，based on the affinity principle of ligand and receptor, as well as the specificity and reversibility of their combination, is a considerably efficient technique for high-throughput screening（HTS） of drugs. Since AC shows obviously the dynamical characters, associating and dissociating between ligands and receptors present in its column, it can present much more information than other related techniques. The information contained by its eluting curve reveals directly the interaction of ligand-target and its quantitative characterization, thereby presenting a convenience to drug discovery. Basing on the analysis of AC-based HTS, the present study establishes a series of qualitative and quantitative models. Because of their usability, these models are normally expected to play a positive role in the future on guiding the process of drug screening.

Relationship Between the Optical Rotatory Direction and Structure of the Cyclophane Derivatives

YIN Yu-Ying, LIU Chun-Yun, TANG Hui-Tong

2006, 23 (1): 39-45. DOI: 10.7523/j.issn.2095-6134.2006.1.007

Abstract ( 1198 ) PDF (KB) ( 0 )

According to the helix theory , In almost all structures of organic compounds exist helices, helix structure is the basic reason of the molecular optical rotation. A left-hand helix will result in left rotation of the plane polarized light and a right-hand helix will result in right rotation of the plane polarized light. The total molecular optical rotatory power (and direction) depends on the algebraic sum of rotations of all helices existed in the molecular structure .Optical active cyclophane derivatives have special structure and can have a variety of change. In this type of compound, designated P, M helix (plus or mines helix ) is not the only helix existed in the molecule, even is not the helix which has the most substantial contribution to the optical rotation, so one should carry out some particular analysis. After carefully analyzing every helix existed in the structure , we can find their optical rotation behavior is similar to the behavior of all other kind of optical active organic compounds, comply well with those rules based on the helix theory, i. e. we can predict their optical rotation direction from the absolute configuration. Conversely, we can deduce their absolute configuration from the optical rotation direction.

Building an Intrusion Tolerant Repository

LIU Hai-Jiao, JING Ji-Wu, LIN Jing-Qiang, DU Jiao

2006, 23 (1): 46-51. DOI: 10.7523/j.issn.2095-6134.2006.1.008

Abstract ( 1160 ) PDF (KB) ( 0 )

On-line ARECA’S ability to protect its private key enables it to sign certificates or revoke certificates securely, yet to be a secure on-line CA, its repository should also be protected. ARECA’S repository comprises several replicated servers and is designed into a Dissemination Quorum System, which can mask the benign failure or Byzantine (even malign) failure of the servers. ARECA’S repository is able to provide correct service even when at most f servers of the n (n>3f) servers fail.

Face Recognition Based on Hidden Markov Model

CAO Lin, WANG Dong-Feng, ZOU Mou-Yan

2006, 23 (1): 52-59. DOI: 10.7523/j.issn.2095-6134.2006.1.009

Abstract ( 1336 ) PDF (KB) ( 0 )

A new algorithm for face recognition based on wavelet transform and hidden Markov model(HMM) is proposed. Three low frequency sub-band images are selected by applying three-level wavelet transform. The low frequency wavelet sub-trees are formed by arranging three low frequency images in order. The feature wavelet sub-tree branches, as observation vectors of HMM, are derived by using independent component analysis. A set of images representing different instances of the same person is used to train each HMM. The relationship between the dimensionality of observation vectors and the recognition rates is shown. The effect of the number of states and Gaussian kernels on the system performance is examined. The essence of HMM is described qualitatively. Experimental results on the ORL face dataset are compared with other published algorithms, and show that the proposed algorithm has a high recognition rate with a good perspective.

A Novel Method to Improve the Bandwidth of Waveguide Slot Array Antenna

ZHANG Ya-Fei, LV Xiao-De

2006, 23 (1): 60-63. DOI: 10.7523/j.issn.2095-6134.2006.1.010

Abstract ( 1142 ) PDF (KB) ( 0 )

The frequency characteristic of the admittance of radiating slot and the waveguide wavelength of radiating waveguide is the main factor that influences the bandwidth of slot array antenna. Based on the idea of improving the frequency characteristic of the two parameters above, a novel method of improving the bandwidth of slot array antenna is presented in this paper, which uses a ridged waveguide instead of a rectangular waveguide as the radiating waveguide. The simulation analysis has indicated that the bandwidth of ridged waveguide slot array has been greatly improved, and it is consistent with the result of thoery. The result of this paper brings forword a new idea for improving the bandwidth of slot array antenna.

Preparation and Characterization of CeO2-ZrO2 Solid Solutions Prepared by Citric Acid Sol-Gel Method

YAO Qing, TIAN Qun, CEHN Hong-De, FANG Shi-Ping, HAN Yun

2006, 23 (1): 64-69. DOI: 10.7523/j.issn.2095-6134.2006.1.012

Abstract ( 1255 ) PDF (KB) ( 0 )

A series of CeXZr1-XO2(x=0.5,0.6 and 0.8)mixed oxides were prepared by citric acid sol-gel method with nitrate solution. It was shown that solid solution had formed after calcination at 600℃ by X-ray diffraction(XRD). The surface and crystal structure of solid solutions were investigated by BET, oxygen storage capacity(OSC) and XRD after calcination at 600℃ and 900℃. With increase of mol%Ce, the specific surface area(SSA) and OSC of samples decreased ,while the stablity reduced by the analysis of XRD. It was shown that the temperature of peak had decreased after calcination at 900℃ by H2-TPR because of complete decomposition of citric complex at high temperature.

Analyses on the Characteristics of Beijing Summer Urban Heat Island (UHI) and Its Meteorological Fields

LIU Xi-Ming, HU Fei, LI Lei

2006, 23 (1): 70-76. DOI: 10.7523/j.issn.2095-6134.2006.1.013

Abstract ( 1329 ) PDF (KB) ( 0 )

In this paper, the summer meteorological data (from 1998 to 2003) from 10 observatories, 1 auto-observatory and the Beijing 325m tower have been used to study the urban heat island (UHI) and the meteorological fields near surface in the summer of Beijing. The results show that the UHI in Beijing summer is very obvious, its average intensity reaches 1.64℃ over the past 6 years; the strong UHI occurs mainly at night (average intensity is 2.62℃ at 02:00 am.). In daytime, it becomes weaker quickly, the average intensity is 0.6℃ at 14:00 pm., sometimes even an urban cold island (UCI) can be found; with the development of urbanization in Beijing, the number of days with UHI intensity more than 2℃ increases year by year, and the strongest UHI reaches 9℃; when the UHI is very strong, the wind field can show an UHI circulation (convergence) with weak wind in urban area. Combined with the data of the 325m tower, the results also show that when strong UHI occurs, the inversion in atmospheric boundary layer (ABL) is very obvious, and its top is very high.

A RF High Power Amplifier Bias circuits Design Technique

SHEN Ming, GENG Bo, YU Pei-Ling

2006, 23 (1): 77-82. DOI: 10.7523/j.issn.2095-6134.2006.1.015

Abstract ( 1253 ) PDF (KB) ( 0 )

When conducting design of RF high power amplifier (HPA), the broadened microstrip λ/4 bias line for high DC current decreases the performance of the HPA. In this article, a thickened microstrip line is proposed to design the λ/4 drain bias circuit for HPA and is applied to a power amplifier for a miniaturized satellite transmitter. Measurement results showed that thickened bias line is feasible and useful for increasing HPA’s performance.

Optimized Regulation Model of Human-Earth System Based on System Dynamics

CHENG Ye-Qing

2006, 23 (1): 83-90. DOI: 10.7523/j.issn.2095-6134.2006.1.016

Abstract ( 2041 ) PDF (KB) ( 0 )

study of human-earth system is the most important content in geography; regional sustainable development relies on the reasonable structure optimal model and effective regulation of regional human-earth system. County region is a complex and opening human-earth system, taking Huangling county as an example, the environment, resources exploitation, economic development and structure evolvement of industry were systematically analyzed. And the systematical dynamic model was established and multi-projects were simulated with the theory and method of system dynamic. Optimized regulation models of human-earth system evolvement were educed based on three projects: (1) Traditional evolvement method. The intensity of resource exploitation and environment pollution is the least, but the speed of its economy development is the lowest, which restrict social sustainable development and economic reproduction. (2) Economy development method. The intensity of resource exploitation and environment pollution is the worst, economic development mostly depends on higher investment and pollution, which is a traditional mode of unsustainable development. (3) Harmonious development mode. The mode considers not only economic sustainable development and natural recourses utilizing reasonably, but also gives more attention to environment protection and harmonious development of industry, agriculture, tourism and so on. It is the optimized mode of the human-earth system evolvement.

Regional Economic Development Policy and Regional Economic Growth Convergence in China, 1952-2000

GUO Teng-Yun, XU Yong, YANG Guo-An

2006, 23 (1): 91-96. DOI: 10.7523/j.issn.2095-6134.2006.1.019

Abstract ( 1411 ) PDF (KB) ( 0 )

In this paper, the regional economic growth convergence across provinces in China during the period 1952-2000 is scrutinized using an econometric model. The results in this paper provide new insights on regional economic growth change across provinces in China during the period. On the whole, there were no regional economic growth convergences in terms of per capita real GDP during the period 1952-2000. But during the sub-periods with relatively favorable economic development environment in the sample period, there were not only absolute b convergences, but also conditional b convergences during the sub-periods 1979-2000, 1979-1990; and during the sub-period 1990-2000 there was conditional b convergence; whereas during the sub-period 1966-1979, which was full of political turmoil, there was no convergence at all, there was an evident divergence instead. The empirical analysis also shows that there were significant associations between regional economic growth convergences and regional development policy statistically. With the introduction of regional policy variable in the econometric model the b convergences become even more evident and significant statistically, which further reveal that effect of regional development policy on regional economic development is essential in Chinese regional economic development. So in the course of regional economic development as long as the Chinese central government and local governments bring into full play of regional economic growth convergence and give full support to the underdeveloped areas in China from policy side, the increasingly regional economic disparities can be kept within limits efficiently.

Research on Models and Types of Less-developed Region Based on Natural and Human Factors

YANG Xiao-Guang , WANG Chuan-Sheng, SHENG Ke-Rong

2006, 23 (1): 97-104. DOI: 10.7523/j.issn.2095-6134.2006.1.020

Abstract ( 1105 ) PDF (KB) ( 0 )

To promote development of less-developed regions and reduce the gap are embodiment of fulfilling scientific development view. Less-developed regions are identified then assorted types by GIS spatial analysis method. On the base of this, this paper brought forward four main developing models for less-developed regions by the analysis of intensions of each restricting factors and natural human condition to economy development. At the end of this paper, direct policy suggestions on each developing models are produced.

Case Study of Water-Soluble Anionic Component of Aerosol in Taipei, China

WEN Tian-Xue, WANG Yue-Si, HE Xin-Xing

2006, 23 (1): 105-110. DOI: 10.7523/j.issn.2095-6134.2006.1.021

Abstract ( 1116 ) PDF (KB) ( 0 )

Three days were selected to study the effect of different long-distance transportation on atmospheric pollution in Taipei, China. Concentration of water-soluble anion of aerosols in Taipei was measured. Back trajectory of air masses, mass ratio and sources of water-soluble anions were analyzed. The results showed that water-soluble anion of aerosol in Taipei was composed of Cl-, NO2-, NO3- and SO42-. SO42- was the major component, which accounted for 60-90% in mass, and then following is NO3- which accounted for 9-22% in mass. SO42- and NO3- were likely from the same source. Concentration of NO2- could not be ignored. Long-distance transportation of sea-salt aerosol could decrease atmospheric pollution in Taipei. However, long-distance transportation of aerosols from coastland of China could increase atmospheric pollution in Taipei. Long-distance transportation of dust was not always increase atmospheric pollution in Taipei

Study of a Fuzzy Logic Controller for Satellite Maneuver Control

WANG Shu-Quan, ZHAO Guang-Heng

2006, 23 (1): 111-117. DOI: 10.7523/j.issn.2095-6134.2006.1.022

Abstract ( 1997 ) PDF (KB) ( 0 )

In this paper, a typical Mamdani PD type Fuzzy Logic Controller is outlined for Satellite Maneuver Control. The design of the controller is based on experiences and expert’s knowledge, and because of the utilization of human’s intelligence, the controller is very agile and has its special attributes. Through simulation, controller’s characters with various parameters are demonstrated. A traditional I/O linearized PID controller is used to compare with the Fuzzy Logic Controller. The robustness quality of Fuzzy Logic Controller is verified. Results presented substantiate the feasibility of using Fuzzy Logic Controller in satellite maneuver control problem.

Study on Morphological Response of the Alpine Steppes Plant Individuals to Grazing Stress

HAN You-Ji, CHEN Gui-Chen, ZHOU Guo-Ying, SUN Jing, LI Jin-Ping

2006, 23 (1): 118-124. DOI: 10.7523/j.issn.2095-6134.2006.1.023

Abstract ( 1319 ) PDF (KB) ( 0 )

Compared with the grass individuals of alpine steppes community fenced for twenty years, the variation of morphological characteristic of four good herding grass species( Stipa purpurea, Agropyron cristatum, Poa pratensis, Artemisia scoparia) and three miscellaneous poison grass species (Dracocephalum heterophalum, Thermopsis lanceolata, Stellera chamaejasme) under grazing stress is studied, we find that the responses of good herding grass individuals to long-term grazing are not consistent with the responses of miscellaneous poison grass individuals. Good herding grass individuals show “Individual Miniaturization Phenomenon”, but miscellaneous poison grass individuals do not become miniaturized, especially for aboveground biomass. Different individual morphological variation results in the change of utilization ability to environmental resources, so the environmental spaces and resources (hypervolume niche) each population occupies in the community becomes “reshaped”, that of most good herding grass populations becomes "contracting " and it is "extending "for most miscellaneous poison grass populations, therefore the status of plant populations in the degraded grassland community changes, the dominant species alternates. This is the individual morphological principles of the degradation of alpine steppes community.

Adaptive 2-Ary Window Representation Algorithm for Pairs of Integers

LI Xue-Jun, HU Lei

2006, 23 (1): 125-130. DOI: 10.7523/j.issn.2095-6134.2006.1.024

Abstract ( 1331 ) PDF (KB) ( 0 )

In the implementation of some public key cryptosystems, in particular, the verification procedure of most common digital signatures (apart from RSA) are required to perform not only exponentiation, but also pairs of exponentiation directly. In this paper, a left-to-right adaptive 2-ary window representation (2-AWR) for pairs of integers is presented and analyzed. Shamir algorithm can be on-line carried out using this representation. And its advantage over other similar algorithm is demonstrated.

Spectroscopic Properties of Rare-Earth Doped Heavy Metal Oxyhalide Glasses

XU Shi-Qing, JIANG Zhong-Hong

2006, 23 (1): 131-136. DOI: 10.7523/j.issn.2095-6134.2006.1.025

Abstract ( 1531 ) PDF (KB) ( 0 )

The goal of this dissertation is mainly to search for glass hosts suitable for broadband fiber amplifiers, blue and green lasers. This research on spectral properties and crystallization stability of Er3+-doped heavy metal oxyfluoride glasses and upconversion luminescence of rare earth-doped heavy metal oxyhalide glasses lay a foundation for the potential use of broadband Er3+-doped fiber amplifier, blue and green lasers. The results showed that the bandwidth properties and gain performance of Er3+-doped silicate and germanate glasses increase due to addition of heavy metal lead fluoride, upconversion blue emission in Er3+/Yb3+-codoped and Er3+-doped silicate glasses was observed for the first time, upconversion luminescence intensity of Er3+-doped germanate and tellurite glasses increase with increasing of heavy metal lead fluoride, upconversion blue, green and red emissions are corresponding to the 2H9/2→4I15/2, 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively, were simultaneously observed at room temperature. Mixed lead halide modified Tm3+/Yb3+-codoped tellurite glasses are profitably improving crystallization stability of host glasses and upconversion luminescence, and upconversion blue and red emission are corresponding to the1G4→3H6 and 1G4→3H4 transitions of Tm3+, respectively, were simultaneously observed at room temperature. It was discovered for the first time that OH group absorption had important effect on upconversion emission of Er3+ and Tm3+ doped tellurite glasses.

Molecular Level Study on the Physicochemical Properties of Geological Fluids

ZHANG Zhi-Gang, DUAN Zhen-Hao

2006, 23 (1): 137-143. DOI: 10.7523/j.issn.2095-6134.2006.1.026

Abstract ( 1868 ) PDF (KB) ( 0 )

It is one of the challenging issues in geosciences to study the physical chemical properties and geochemical behaviors of geological fluids. Compared with conventional approaches of experiments and semi-theoretical modeling, computer simulation based on molecular modeling shows its advantages on quantitative predictions of the physical chemical properties of geological fluids under extreme conditions and emerges as a promising approach to find the characteristics of geological fluids and their interactions in different lithospheres of the Earth interior. In this paper, we give a brief introduction of our experiences in applying computer simulation techniques into the research of geological fluids. The main results can be summarized as follows: (1) we have successfully reproduced the experimental phase behaviors of the typical geological systems with Monte Carlo simulations; (2) through comprehensive isothermal-isobaric molecular dynamics simulations, the PVT data of water have been extended beyond experimental range to about 2000 K and 20 GPa and an improved equation of state for water has been established; (3) based on extensive computer simulations, an optimized molecular potential for carbon dioxide have been proposed, this model is expected to predict different properties of carbon dioxide (volumetric properties, phase equilibria, heat of vaporization, structural and dynamical properties) with improved accuracies; (4) with molecular dynamics simulations and careful analysis, we’ve got various structural, dynamical and thermodynamical properties of lithium chloride ionic solvations and associations, these results not only agree well with experimental data and first principle calculation results, but also reveal some new insights into the microscopic ionic solvation and association processes.

Current Issue