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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

Cascade algorithm and multiresolution analysis on the Heisenberg group

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Progress in Natural Science:Materials International 2005年第7期15卷 602-608页

作者： LIU Heping, LIU Yu, PENG Lizhong and CHU Xiaoyong (LMAM, School of Mathematical sciences, peking university, beijing 100871, china) LMAM School of Mathematical Sciences Peking University Beijing 100871 China

In this paper we investigate the relationship between the convergence of cascade algorithm and orthogonal (or biorthogo-nal) multiresolution analysis on the Heisenberg group. It is proved that the (strong) convergence of cascade algorithm together with the perfect reconstruction condition induces an orthogonal multiresolution analysis and vice versa . Similar results are also proved for biorthogo-nal multiresolution analysis.

关键词： Heisenberg group cascade algorithm multiresolution analysis refinable functions.

Uniqueness and local stability for the inverse scattering problem of determining the cavity

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Science china Mathematics 2005年第8期48卷 1113-1123页

作者： FENG Lixin & MA Fuming LMAM, School of Mathematical sciences, peking university, beijing 100871, china School of Mathematical sciences, Heilongjiang university, Harbin 150080, china School of Mathematical sciences, Jilin university, Changchun 130012, china 1. LMAM School of Mathematical Sciences Peking University 100871 Beijing China 2. School of Mathematical sciences Heilongjiang University 150080 Harbin China 3. School of Mathematical sciences Jilin University 130012 Changchun China

Considering a time-harmonic electromagnetic plane wave incident on an arbitrarily shaped open cavity embedded in infinite ground plane, the physical process is modelled by Maxwell's equations. We investigate the inverse problem of determining the shape of the open cavity from the information of the measured scattered field. Results on the uniqueness and the local stability of the inverse problem in the 2-dimensional TM (transverse magnetic) polarization are proved in this paper.

关键词： uniqueness, stability, Maxwell's equations, inverse scattering problem.

A submillimeter observation and study of star-forming regions

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Chinese Science Bulletin 2002年第1期47卷 16-21页

作者： JIANG Linhua, WU Yuefang & M. MillerDepartment of Astronomy, peking university, beijing 100871, china Chinese Academy of sciences-peking university Joint beijing Astrophysics Center, beijing 100871, china I. Physikalisches Institut, Zulpicher Str Department of Astronomy Peking University Beijing China Chinese Academy of sciences-peking university Joint beijing Astrophysics Center Beijing China I. Physikalisches Institut Koeln 41 Germany

Using the 3-m radio telescope of KOSMA, we mapped 12CO (J = 3-2) lines for three molecular clouds, B35, S146 and TMC-2A. High-velocity molecular outflows are found in all these regions. The physical and dynamical pa-rameters of the outflows are derived, and their shapes and driving sources are analyzed. Contour maps of center veloci-ties show that the large scale systematic gradients exist in the three clouds. These observed motions are best explained by rotation after excluding the cause of outflows. Furthermore, in the core region of TMC-2A there is a velocity gradient in opposite direction from that of the large scale. It may be caused by magnetic braking. Finally, angular velocities of the clouds are calculated, and the effects of rotation against gravity and lowering the star-formation rate are also ana-lyzed.

关键词： dynamics of interstellar medium jets and outflows star formation.

A New Competitive Inhibitory Monoclonal Antibody to Carboxypcptidase A(CPA)

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Chinese Chemical Letters 1999年第2期10卷 121-122页

作者： Mei DU Sheng JIN Zhen Quan GUO(college of Chemistry and Molecular Engineering. peking university. 100871)(college of life Science, peking university, 100871) peking Univ Coll Chem & Mol Engn Beijing 100871 Peoples R China peking Univ Coll Life Sci Beijing 100871 Peoples R China

The monoclonal antibody ID11D7 to carboxypeptidase A (CPA) was prepared. Theinhibitory effect of McAb ID11D7 on the peptidase activity of CPA was measured. The result reflectsthat the McAb ID11D7 can competitively inhibit the peptidase activity of CPA with an apparentinhibitory constant of 6.3 × 10-9M. Based on this work. the McAb ID11D7 can be used as idiotypicantigen to prepare anti-idiotypic catalytic antibody with the peptidase activity similar to CPA.

关键词： Monoclonal antibody carboxypeptidase A (CPA) competitive inhibition peptidaseactivity

Morita contexts on the Hopf algebroid

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Science china Mathematics 2005年第7期48卷 958-971页

作者： YIN Yanmin School of Mathematical sciences, peking university, beijing 100871, china Department of Mathematics, Shandong Institute of Architecture and Engineering, Jinan 250101, china 1. School of Mathematical sciences Peking University 100871 Beijing China 2. Department of Mathematics Shandong Institute of Architecture and Engineering 250101 Jinan China

We generalize the Morita theory to the Hopf algebroid and give the characterization of the surjectivity of one of the Morita context maps.

关键词： comodule algebra, generalized smash product, Morita context.

Role of atmospheric heat source/sink over the Qinghai-Xizang Plateau in quasi-4-year oscillation of atmosphere-land-ocean interaction

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Chinese Science Bulletin 2001年第3期46卷 241-245页

作者： ZHAO Ping & CHEN LongxunDepartment of Geophysics, peking university, beijing 100871, china Chinese Academy of Meteorological sciences, beijing 100081, china Department of Geophysics Peking University Beijing China Chinese Academy of Meteorological sciences Beijing China

Using 1961-1995 monthly atmospheric apparent heat source/sink over the Qinghai-Xizang Plateau (QXP)and reanalysis data of NCEP/NCAR, and 1961 ?1994 monthly SST of UK/GISST2, the statistical study is undertaken on the QXP heat source/sink in relation to both atmospheric circulation in Asia and El Nino/La Nina events. It is discovered that there exists noticeable interaction in aquasi-4-year period among the of the QXP, low-levelmeridional winds east of the QXP, low-level zonal winds in the equatorial Pacific, SST in the equatorial eastern Pacific, and the circulation at mid and high latitudes north of the QXP. They have difference in phase. The cold source intensity of the QXP in winter favours a low-level meridional wind anomaly to prevail in the mainland of china and its coast east of the QXP and to last until the subsequent autumn. The wind anomaly can induce a low-level zonal wind anomaly of the tropic Pacific that finally affects an El Nino/La Nina event in the autumn and subsequent winter.

关键词： Qinghai-Xizang Plateau thermal effect interannual variation atmosphere-land-ocean interaction.

Theory of optimal blocking for fractional factorial split-plot designs

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Science china Mathematics 2005年第5期48卷 649-656页

作者： Al Mingyao & HE Shuyuan Key Laborartory of Pure and Applied Mathematics, School of Mathematical sciences, peking university, beijing 100871, china 1. Key Laborartory of Pure and Applied Mathematics School of Mathematical Sciences Peking University 100871 Beijing China

The issue of optimal blocking for fractional factorial split-plot (FFSP) designs is considered under the two criteria of minimum aberration and maximum estimation capacity. The criteria of minimum secondary aberration (MSA) and maximum secondary estimation capacity (MSEC) are developed for discriminating among rival nonisomorphic blcoked FFSP designs. A general rule for identifying MSA or MSEC blocked FFSP designs through their blocked consulting designs is established.

关键词： blocking consulting design estimation capacity minimum secondary aberration fractional factorial split-plot design.

Developmental sequence of Cambrian embryo Markuelia

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Chinese Science Bulletin 2007年第7期52卷 929-935页

作者： DONG XiPing1,2 1 School of Earth and Space sciences, peking university, beijing 100871, china 2 Laboratory of Palaeobiology & Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of sciences, Nan-jing 210008, china (email: dongxp@***) School of Earth and Space sciences Peking University Beijing 100871 China

Based on more exquisitely preserved specimens of Markuelia hunanensis recently recovered from Middle and Upper Cambrian in western Hunan and in the light of Synchrotron radiation X-ray tomo-graphic microscopy, the developmental sequence from cleavage through organogenesis to the pre-hatching of Cambrian embryo Markuelia, especially the developmental sequence during the pre-hatching stage, i.e. from the earliest period when the scalids and tail spines only took shape to the latest period (just about hatching), is established. This developmental sequence provides a pattern of embryonic development during the pre-hatching stage, which has not been established in the living scalidophorans (priapulids, loriciferans and kinorhynchs). Thus, it not only enriches our knowledge on the embryonic development of the extant descendants of Markuelia, but also opens a new window to the evolution and development of the animal.

关键词：寒武纪蠕虫化石胚胎发育序列两侧对称动物胚胎