检索结果-南通市图书馆

Response synchronization: New progress in brain-visual information {2.

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第16期44卷 1447-1458页

作者： ZHAO Songnian, XIONG Xiaoyun, YAO Guozheng and GUO Aike1. State Key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry , institute of Atmospheric Physics , Chinese Academy of {2. , {3. 10002., china 2. Commission of the National Natural Science Foundation of china , {3. 100083. china 3. The Center of information Science , Peking University, {3. 100871, china 4. Open laboratory of {12. information processing , institute of biophysics , Chinese Academy of {2. , beijing 100101, china State Key laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Commission of the National Natural Science Foundation of china Beijing China The Center of information Science Peking University Beijing China Open laboratory of visual {2. {3. Institute of Biophysics Chinese Academy of Sciences Beijing China

Studies on brain-vision have entered a new stage, after the stimulus-induced y synchronized oscillation of neuron group activities have been discovered in cat primary visual cortex. Naturally, how to understand the visual system became a very important methodological problem. From aspects such as {2. {3., nonlinear dynamics and neuronal network, some primary problems in vision studies have been deeply discussed, which are

关键词： neuron group (neural population) synchro-oscillation computational theory of vision response synchroniza-tion.

Antioxidant effects of green tea polyphenols

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第4期48卷 315-319页

作者： ZHAO Baolu laboratory of visual {2. {3., Research Centers of Brain and Cognitive Science, institute of biophysics, Chinese Academy of sciences, beijing 100101, china laboratory of visual {2. {3. Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

The unprecedented interest in the antioxidant activity of green tea polyphenols (GTP) is due to the appar-ent health benefits of tea drinking and the experimental re-sults with the polyphenols. The results suggest that the gal-loylated catechins show stronger antioxidant effect than that of nongalloylated catechins and the double bond in C ring also plays an important role in this effect. There are synergic effects between different catechins and the antioxidant effect of (+)-epimers is stronger than that of (-)-epimers. The active site to scavenge free radicals mainly locates in p-hydroxyl of phenol in gallic acid and hydroxyl of phenol in the pyrane also shows activity. The large p bond in chromane and benzene ring of catechin is the structure base for their anti-oxidant effects. The prevent effect of GTP against diseases and their redox regulation in cell signal pathway are very important to be studied in the future.

关键词：绿茶茶多酚天然抗氧化剂抗氧化作用生物类黄酮自由基抗衰老

The universal fuzzy logical framework of neural circuits and its application in modeling primary visual cortex

在线全文

学校读者我要写书评

暂无评论

Science china(Life sciences) 2008年第10期51卷 902-912页

作者： HU Hong1, LI Su2. WANG YunJiu2. QI XiangLin2.& SHI ZhongZhi1 1 Key {3. of Intelligent information {2., institute of Computing Technology, Chinese Academy of sciences, beijing 100080, china 2.{3. of visual information {2., institute of biophysics, Chinese Academy of sciences, beijing 100101, china Key laboratory of Intelligent information {2. Institute of Computing Technology Chinese Academy of Sciences Beijing China laboratory of visual {2. {3. Institute of Biophysics Chinese Academy of Sciences Beijing China

Analytical study of large-scale nonlinear neural circuits is a difficult task. Here we analyze the function of neural systems by probing the fuzzy logical framework of the neural cells' dynamical equations. Al- though there is a close relation between the theories of fuzzy logical systems and neural systems and many papers investigate this subject, most investigations focus on finding new functions of neural systems by hybridizing fuzzy logical and neural system. In this paper, the fuzzy logical framework of neural cells is used to understand the nonlinear dynamic attributes of a common neural system by abstracting the fuzzy logical framework of a neural cell. Our analysis enables the educated design of network models for classes of computation. As an example, a recurrent network model of the primary visual cortex has been built and tested using this approach.

关键词： nonlinear dynamical system fuzzy logic visual cortex

Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 450-458页

作者： YU Bin1,2. PENG Xiang1,2. TIAN Jindong1, NIU Hanben1, DIAO Luhong3.& LI Hua3.1. Key laboratory of Optoelectronic Devices and Systems of Ministry of Education, {3. of Optoelec- tronics, Shenzhen University, Shenzhen 518060, {2. 2. State Key laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 3.0072.{2. 3. Key laboratory of Intelligent information processing, {3. of Computing Technology, Chinese Academy of {13., beijing 100080,{2. Key laboratory of Optoelectronic Devices and Systems of Ministry of Education Institute of Optoelectronics Shenzhen University Shenzhen China State Key laboratory of Precision Measuring Technology and Instruments Tianjin University Tianjin China Key laboratory of Intelligent information {2. Institute of Computing Technology Chinese Academy of Sciences Beijing China

Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

关键词： X-ray optics, phase contrast imaging, phase retrieval, angular spectrum, hard X-ray.

Discovery of immune related factors in Fenneropenaeus chinensis by annotation of ESTs

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2004年第1期14卷 48-55页

作者： SHEN Yaoqing 1,2. , XIANG Jianhai 1*, WANG Bing 1,2. , LI Fuhua 1 and TONG Wei 3.1. Experimental Marine Biology laboratory, {3. of Oceanology, Chinese Academy of {2., Qingdao 2.6071,china 2. Graduate School of the Chinese Academy of {2., beijing 10003., china 3. Genomics & Bioinformatics {3., Chinese Academy of {2., beijing 1013.0, china) Chinese Acad Sci Inst Oceanol Expt Marine Biol Lab Qingdao 266071 Peoples R China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China Chinese Acad Sci Geonom & Bioinformat Inst Beijing 101300 Peoples R China

A total of 10446 expressed sequence tags (ESTs) are obtained by a large scale sequencing of a cDNA library from cephalothorax of adult Fenneropenaeus chinensis . An EST analysis platform was built up based on local computers and bioinformatic techniques were used to annotate these ESTs in order to promptly find possible functional genes, especially for immune related factors. About 4% of the ESTs show similarity to the coding sequences of such factors, including lectin, serine protease, serpin, lysozyme, etc. These ESTs provide a partial profile of the immune system in F. chinensis and useful information for further study on these genes.

关键词： Fenneropenaeus chinensis bioinformatics ESTs immune factors

Two possible mechanisms for vortex self-organization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2. ZHOU Xiuji1 & GAO Shouting3.1. Chinese Academy of Meteorological sciences, beijing 100081, {2. 2. Department of Space information Science, Nanjing University of information Science and Technology, Nanjing 2.0044, {2. 3. institute of Atmospheric Physics, Chinese Academy of sciences, beijing 10002., {2. Department of Environmental Science Nanjing University of Information Science and Technology Nanjing China Chinese Academy of Meteorological sciences Beijing China institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

A formal model of fair exchange protocols

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2005年第4期48卷 499-512页

作者： QING Sihan1,2.3.& LI Gaicheng1,2.3.1. Engineering Research Center for information Security Technology, {3. of Software, Chinese Aca- demy of {2., beijing 100080, china 2. beijing Zhongke Ansheng Corporation of information Technology, beijing 100080, china 3. Graduate School of the Chinese Academy of {2., beijing 10003., china Engineering Research Center for information Security Technology Institute of Software Chinese Academy of Sciences Beijing China beijing Zhongke Ansheng Corporation of information Technology Beijing China Graduate School of the Chinese Academy of sciences Beijing China

Based on the study of existing fair exchange protocols, this paper sets up an accurate formal model by stepwise refinement. In the process of refinement an unreliable channel is employed to simulate an attack behavior. The model provides a novel formal definition of exchanged items, and presents the formal goals for fairness, accountability, etc., reflecting the inherent requirements for fair exchange protocols across-the-board. In order to check, prove, and design fair exchange protocols effectively and efficiently, the model puts forward a novel property of abuse-freeness which applies to all fair exchange protocols, gives a formal definition for trust strand of the third party, and presents general criteria of designing a secure and effective fair exchange protocol. Taking a typical fair exchange protocol as an example, this paper presents the analysis steps of fair exchange protocols appealing to our model. An unknown attack is uncovered. The analysis reveals the process of a complete attack, discovering deeper reasons for causing an attack. Finally, we modify the flawed protocol and the revised protocol ensures the desirable properties.

关键词： events local causal relation local temporal relation global relation exchanged item security goals.

Binaurality and azimuth tuning of neurons in the auditory cortex of the big brown bat

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第12期47卷 1024-1027页

作者： SHEN Junxian & CHEN QicaiCenter for Brain and Cognitive Science, laboratory of visual {2. {3., institute of biophysics, Chinese Academy of sciences, beijing 100101, china Department of Biology, Central china Normal University, Wuhan 43.070, Lab. of visual Info. processing Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

By using a combined closed and free-field stimulation system, binaurality and azimuth tuning of the neurons in the auditory cortex of the big brown bat, Epte-sicus fuscus, were studied. A variety of azimuth-tuning functions were demonstrated for the binaural neurons. The large majority of EE (contralateral and ipsilateral excitatory) neurons exhibited azimuth selectivity with the best azimuths (BA) at contralateral 3.°-40°, some at ipsilateral 2.°-40° and preferred azimuth ranges (PAR, response amplitude >75% of maximum) between 8° and 40°. Sound source azimuths strongly modulate spike counts with a mean modulation depth of 83.8% for EE neurons. EI (contralateral excitatory and ipsilateral inhibitory) neurons have simple azimuth tuning with BA located at contralateral 2.°-40° and a broad PAR ranged from 3.° to 55°. The present results suggest that azimuth-tuning characteristics of binaural neurons in the auditory cortex of the bat are of significance for acoustic behaviour.

关键词： bat auditory cortex binaural neurons azimuth tuning.

A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2. ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3.1. International Center for Climate and Environment sciences, institute of Atmospheric Physics, Chinese Academy of sciences, beijing 10002., china 2. Jiangsu Key laboratory of Meteorological Disaster, Nanjing University of information Science and Technology, Nanjing 2.0044, china 3. beijing institute of Applied Meteorology, beijing 10002., china International Center for Climate and Environment sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Jiangsu Key laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing China beijing institute of Applied Meteorology Beijing China

A new 3.VAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3.VAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 2.-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 42. m reach 0.63. and 0.3. psu.

关键词： data assimilation, 3.VAR, sea surface height, ARGO floats.