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A　CONVENIENT　METHOD　FOR　SYNTHESIZING　AND　CHARACTERIZATION　OF　（Z）－ALKENOLS　AND　THEIR　ACETATES

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Chinese Chemical Letters 1995年第11期6卷 943-944页

作者： Gu YUAN(Department of Chemistry,Peking university, beijing\ 100871) beijing Univ Dept Chem Beijing 100871 Peoples R China

All double bond positional isomers of (Z)-dodecenol, (Z)-tetradecenol, (Z)hexadecenol and their acetates were synthesized by the Wittig reaction and the coupling reaction, and a novel procedure for the identification ...

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A note on extremal quasi-conformal mappings

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Science China Mathematics 2010年第1期53卷 63-70页

作者： LI ZhongSchool of Mathematical Sciences,Peking university,beijing 100871,China 1. School of Mathematical Sciences Peking University Beijing 100871 China

An extremal quasi-conformal mapping f of a domain D is said to be of non-landslide type if the set Ef(δ):= {z∈D:|μf(z)|≤||μ|| ∞ -δ} has no interior points for any δ > 0. In this paper,we construct a quasi-conformal mapping f of the unit disc D such that its Teichmu¨ller equivalence class [f] contains infinitely many extremal mappings of non-landslide type. The relation between extremal mappings of non-landslide type and locally extremal mappings is also discussed.

关键词： quasi-conformal mappings extremal quasi-conformal mappings locally extremal quasi-conformal mappings

On Riemann-Finsler geometry

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Chinese Science Bulletin 1998年第6期43卷 447-450页

作者： MO Xiaohuan School of Mathematical Sciences, Peking university, beijing\ 100871, China School of Mathematical Sciences Peking University Beijing China

The history of Finsler geometry is reviewed and briefly recent development in Finsler geometry and its application is completed systematically. Furthermore, an interesting open problem has been proposed in this field.

关键词： Finsler space Chern connection Hilbert form Minkowski potential projective sphere bundle.

Infall and Outflow Activities in the Be star FY CMa

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Chinese Journal of Astronomy and Astrophysics 2001年第6期1卷 514-524页

作者： Hui-Lai Cao National Astronomical Observatories, Chinese Academy of Sciences, beijing 100012 CAS-PKU Joint beijing Astrophysics Center, Peking university, beijing\ 100871 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 []CAS-PKU Joint Beijing Astrophysics Center Peking University Beijing 100871

Unusual activity of outflow mass motion connected with infall events was recorded for the B0.5 IVe star FY CMa in February 1987 from both archival IUE spectrograms of circumstellar N v resonance lines and optical spectra of Ha and HeI γ5876 A emission lines which showed inverse P Cygni-type profiles. We estimate the mass loss rate using ultraviolet Si IVresonance lines with expanding atmosphere modeling calculations, and describe how the radial pressure performs the dominant role in accelerating the stellar wind. We attempt to give a qualitative explanation for the activity observed for FY CMa in terms of circumstellar matter raining down to the star.

关键词： line: proffles - stars: activity - stars: emission-line Be -circumstellar matter - stars: mass-loss - ultraviolet: stars

Progress in cognitive neuroscientific studies of visual awareness

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Progress in Natural Science:Materials International 2009年第2期19卷 145-152页

作者： Qi Li,Haiyan Geng Department of Psychology,Peking university,beijing 100871,China [a]Department of Psychology Peking University Beijing 100871 China

The psychological and neural mechanisms of consciousness are among the most baffling problems in cognitive neuroscience. In this field,visual awareness is a topic that has been largely investigated,due to easy manipulation and measurable effects. The present arti-cle begins with the phenomena of dissociations between visual awareness and visual stimulus,visual awareness and visual attention,as well as visual awareness and vision-guided behavior,along with the corresponding experimental evidence. Furthermore,the neural mechanism of visual awareness is also discussed. It has been generally believed that visual awareness is the function of higher-order cerebral areas; however,recent discoveries have demonstrated that feedback from higher-to lower-order cortex areas is necessary for generating consciousness. The present article presents an in-depth analysis regarding this feedback process,and exploring its relation-ship with the generation and mechanisms of consciousness. Finally,theoretical controversies and discrepancies,as well as result con-flicts from various studies,have been collected,compared and discussed. Because the field of consciousness continues to be an extremely mysterious and complicated psychological phenomenon,there is a great need for further studies to explore and clarify this topic.

关键词： Visual awareness Neural mechanism Feedback process Cortical areas

The effect of discharge conditions of ICP etching reactor on plasma parameters

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Acta Mechanica Sinica 2009年第6期25卷 769-776页

作者： Yijia Lu Yaosong Chen Yiran An LTCS, College of Engineering, Peking university,100871 beijing, China LTCS College of Engineering Peking University 100871 Beijing China

This study investigated the inductively coupled plasma etching reactor and RF coils developed by North Microelectronic Corporation. Full three dimensional simulations were made at different discharge conditions. The simulations examined and compared the distribution and non-uniformity of several plasma parameters at a fixed position upon the wafer at different pressures and coil currents. These parameters included electron density, electron temperature and power deposition. The results demonstrate that the electron density, power deposition and uniformity increase with either higher pressure or stronger coil currents, while the electron temperature decreases at this condition. Coil number increase can reduce the non-uniformity of parameters in the spatial distribution. The linear relationship between power deposition and electron density does not always exist. The comparison between simulation results and experiment results is also presented in the paper.

关键词： Inductively coupled plasma. Electron densityElectron temperature ~ Power deposition - RF coils

Global perception depends on coherent work of bilateral visual cortices: Transcranial magnetic stimulation (TMS) studies

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Science China(Life Sciences) 2007年第4期50卷 557-565页

作者： ZHANG Xin1 & HAN ShiHui1,2 1 Department of Psychology, Peking university, beijing\ 100871, China 2 Learning & Cognition Lab, Capital Normal university, beijing 100875, China 1. Department of Psychology Peking University Beijing 100871 China 2. Learning & Cognition Lab Capital Normal University Beijing 100875 China

Previous research suggests that the right and left hemispheres dominate global and local perception of hierarchical patterns, respectively. The current work examined whether global perception of hierarchi-cal stimuli requires coherent work of bilateral visual cortices using transcranial magnetic stimulation (TMS). Subjects discriminated global or local properties of compound letters in Experiment 1. Reaction times were recorded when single-pulse real TMS or sham TMS was delivered over the left or right visual cortex. While a global precedence effect (i.e., faster responses to global than local targets and stronger global-to-local interference than the reverse) was observed, TMS decreased global-to-local interference whereas increased local-to-global interference. Experiment 2 ruled out the possibility that the effects observed in Experiment 1 resulted from perceptual learning. Experiment 3 used compound shapes and observed TMS effect similar to that in Experiment 1. Moreover, TMS also slowed global RTs whereas speeded up local RTs in Experiment 3. Finally, the TMS effects observed in Experiments 1 and 3 did not differ between the conditions when TMS was applied over the left and right hemispheres. The results support a coherence hypothesis that global perception of compound stimuli depends upon the co-herent work of bilateral visual cortices.

关键词： global perception visual cortex transcranial magnetic stimulation (TMS) compound stimulus

A malware detection model based on a negative selection algorithm with penalty factor

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Science China(Information Sciences) 2010年第12期53卷 2461-2471页

作者： ZHANG PengTao 1,2 , WANG Wei 1,2 & TAN Ying 1,2 1 Department of Machine Intelligence, School of Electronics Engineering and Computer Science, Peking university, beijing\ 100871, China 2 Key Laboratory of Machine Perception, Ministry of Education, Peking university, beijing\ 100871, China 1. Department of Machine Intelligence School of Electronics Engineering and Computer Science Peking University Beijing 100871 China2. Key Laboratory of Machine Perception Ministry of Education Peking University Beijing 100871 China

A malware detection model based on a negative selection algorithm with penalty factor (NSAPF) is proposed in this paper. This model extracts a malware instruction library (MIL), containing instructions that tend to appear in malware, through deep instruction analysis with respect to instruction frequency and file frequency. From the MIL, the proposed model creates a malware candidate signature library (MCSL) and a benign program malware-like signature library (BPMSL) by splitting programs orderly into various short bit strings. Depending on whether a signature matches "self", the NSAPF further divides the MCSL into two malware detection signature libraries (MDSL1 and MDSL2), and uses these as a two-dimensional reference for detecting suspicious programs. The model classifies suspicious programs as malware and benign programs by matching values of the suspicious programs with MDSL1 and MDSL2. Introduction of a penalty factor C in the negative selection algorithm enables this model to overcome the drawback of traditional negative selection algorithms in defining the harmfulness of "self" and "nonself", and focus on the harmfulness of the code, thus greatly improving the effectiveness of the model and also enabling the model to satisfy the different requirements of users in terms of true positive and false positive rates. Experimental results confirm that the proposed model achieves a better true positive rate on completely unknown malware and a better generalization ability while keeping a low false positive rate. The model can balance and adjust the true positive and false positive rates by adjusting the penalty factor C to achieve better performance.

关键词： penalty factor negative selection algorithm signature extraction artificial immune system mal- ware detection

Mapping the Antigenic Peptides of Sm26/2 in Glutathione S-Transferases of Schistosoma Mansoni

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Chinese Chemical Letters 1998年第4期9卷 377-379页

作者： Jia Xi XU Meng Shen CAI(College of Chemistry and Molecular Engineering, Peking university, beijing\ 100871 (School of Pharmaceutical Sciences, beijing Medical university, beijing 100083) Peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China beijing Med Univ Sch Pharmaceut Sci Beijing 100083 Peoples R China

Six antigenic peptides of Sm26/2 glutathione S-transferase of schistosoma mansoni have been predicted according to their hydrophilicity, flexibility, accessibility, charge distribution and beta-turn in the secondary structure by the determination of its primary structure, and synthesized by solid phase method. Two of them showed good antigenicity by Dot-ELISA. They would be candidate peptides of synthetic anti-schistosomal vaccine.

关键词： schistosoma mansoni glutathione S-transferase antigenic peptide peptide vaccine