检索结果-南通市图书馆

木聚糖酶分子结构与重要酶学性质关系的研究进展

在线全文

学校读者我要写书评

暂无评论

生物工程学报 2005年第1期21卷 6-11页

作者：杨浩萌姚斌范云六中国农业科学院饲料研究所北京100081 中国农业科学院生物技术研究所北京100081

木聚糖是一种多聚五碳糖 ,是植物细胞中主要的半纤维素成分。木聚糖酶是可将木聚糖降解成低聚木糖和木糖的水解酶 ,它在饲料、造纸、食品、能源工业和环境科学上有着广阔的应用前景。随着分子生物学、结构生物学的发展及蛋白质工程的应... 详细信息

木聚糖是一种多聚五碳糖 ,是植物细胞中主要的半纤维素成分。木聚糖酶是可将木聚糖降解成低聚木糖和木糖的水解酶 ,它在饲料、造纸、食品、能源工业和环境科学上有着广阔的应用前景。随着分子生物学、结构生物学的发展及蛋白质工程的应用 ,对木聚糖酶结构和功能的研究不断深入。这里重点阐述与酶的活性、热稳定性、作用pH、等电点、底物亲和性及催化效率等重要性质相关的分子结构研究进展 ,讨论了其进一步的研究发展方向。研究木聚糖酶结构与功能的关系 ,对进一步加深木聚糖酶作用机制的了解、指导木聚糖酶的分子改良有重要意义。

关键词：木聚糖酶结构与功能催化残基热稳定性 pH性质底物亲和性

Estimating compositions of natural ringwoodite in the heavily shocked Grove Mountains 052.49 meteorite from Raman spectra

在线全文

学校读者我要写书评

暂无评论

Estimating compositions of natural ringwoodite in the heavil...

中国科学院地质与地球物理研究所第11届（2.11年度）学术年会

作者： L.Feng,~(1,2. Y.Lin,~(1,*) S.Hu,~(1,2. L.Xu,~3.and B.Miao~4 1 Key Laboratory of the Earth’s Deep Interior,Institute of Geology and Geophysics,chinese {3. of {2.,beijing 10002.,china 2.Graduate school of chinese {3. of {2.,beijing 100118,china 3.National Astronomical Observatory,chinese {3. of {2.,beijing 10002.,china 4 Department of Resources and Environmental Engineering,Guilin University of Technology,Guilin 541004,china

A combined Raman spectroscopy and electron probe microanalysis study of the heavily shocked Grove Mountains(GRV) 052.49 meteorite revealed the largest chemical fractionation of natural ringwoodite,and composition-dependent variation of the intensities and/or wavenumbers of Raman *** Fa content[atomic ratio of Fe/(Fe+Mg)]of ringwoodite varying from 2..8 to 81.6 mol%, the peak position of the single band around 2.0 cm(SB1),which relates to the SiO translation mode,shifts from 2.6.0 to 2.4.6 cm,and one of the doublets around 790 cm(DB1),which relates to the symmetric stretching of SiO,shifts from 796.3.to 782.7 *** addition,the relative intensities of SB1 and the other band of the doublet around 840 cm(DB2.,which relates to asymmetric stretching of SiO,increases with Fa *** on the paired Raman-EPMA data,single-peak and two-peak calibrations were established,which can be used to derive Fa contents of ringwoodite from the Raman *** accuracy of Raman-derived Fa content of ringwoodite is better than±5 mol%.The correlation of SBl intensity with the Fa content of ringwoodite suggests that the vibration of SBl is enhanced with the substitution of Mg by *** correlation between Raman spectra and the chemical composition of ringwoodite have potential applications in on-line measurement of high-pressure experiments and in situ mineralogical determination in future planetary explorations.

关键词： Raman spectroscopy ringwoodite chemical compositions shocked meteorite

Influence of prolonged optic flow stimuli on spontaneous activities of cat PMLS neurons

在线全文

cnki会议

学校读者我要写书评

暂无评论

chinese Science Bulletin 2003年第8期48卷 786-790页

作者： XU Ying, LI Bing & DIAO Yuncheng Laboratory of Visual Information Processing, Institute of Biophysics, chinese academy of {2., {3. 100101, china Correspondence should be addressed to Li Bing (e-mail: lib@sun5.ibp. ***) Laboratory of Visual Information Processing Institute of Biophysics Chinese Academy of Sciences China

Changes in neuronal spontaneous activities after prolonged optic flow stimulation (using the three basic flow modes: translation, radiation and rotation) were inves-tigated by extracellular single-unit recording in cortical area PMLS of the cat. The results showed that the evoked re-sponses decreased with the prolongation of visual stimuli, and the spontaneous activities usually dropped to a lower level after the stimuli were withdrawn. Generally, the reduc-tion in spontaneous activities was larger after adaptation in the preferred direction than in the non-preferred direction. This difference was much pronounced to translation stimuli, but relatively insignificant to radiation and rotation. These points suggest that non-specific fatigue may act as the key factor in adaptation to simple translation, while some kinds of more complicated, direction-specific mechanism may be involved in adaptation to the complex optic flow patterns. In addition, PMLS may play an important role in perception and adaptation to complex motion and the relevant motion after-effects.

关键词：光流刺激自发性活动 PMLS神经细胞猫

The Study on Financial Supervision for chinese Financial Industry under Mixed Operation

在线全文

学校读者我要写书评

暂无评论

The Study on Financial Supervision for Chinese Financial Ind...

2.10 International Conference on Management Science (ICMS 2.10)

作者： Song Wei Institute of Economics chinese academy of Social {2. {3. china

Financial mixed operation refers to that financial institution can offer all financial services（banking,securities,insurance,and trust） and engage in industrial businesses by holding the share *** of self interests,risk diversification,the change of competition condition,and clients’ needs of the diversity of financial products and services,commercial banks make it possible for the mixed operation to be the optimal choice of the banking businesses under dynamic conditions in globalized competition,which results in the diversity and integration of banking businesses.

关键词： finance supervision mixed operation risk guard

Changes of cell morphology and cytoskeleton organization in a hypogeomagnetic field

在线全文

cnki会议

学校读者我要写书评

暂无评论

Changes of cell morphology and cytoskeleton organization in ...

2.11年空间生命与生命起源暨航天医学工程学术研讨会

作者： Wei-chuan Mo~(1,3.,Dong-liang Wang~2.Zi-jian Zhang~(1,3.,Ying Liu~(1,3., Rong-qiao He~(1,3. 1 State Key Laboratory of Brain and Cognitive Science,Institute of Biophysics,chinese academy of {2.,15 Datun Road,Chaoyang District,beijing 100101,china 2.National Center for Nanoscience and Technology,chinese academy of {2.,11 Zhongguancun Beiyitiao,Haidian District,beijing 100190,china 3.Graduate University of the chinese academy of {2.,19 A Yuquan Road,beijing,100049,china.

＜正＞Hypogeomagnetic field（HGMF）refers to a geomagnetic field（GMF）eliminated environment,which is one of the characteristic environmental factor in outer space. Recent studies have shown that hypogeomagnetic exposures exhibit adverse effects on embryonic development and animal ***,astronauts are under potential risks due to the hypogeomagnetic aerospace during the space missions. However,the mechanisms of the HGMF effects remain unclear.

关键词：

Shear viscosity to entropy density ratio and liquid-gas phase transition

在线全文

cnki会议

学校读者我要写书评

暂无评论

Shear viscosity to entropy density ratio and liquid-gas phas...

第十四届全国核物理大会暨第十届会员代表大会

作者： s.x.Li 1, 2.D.Q.Fang1 Y.G..Ma1 1 Shanghai Institute of Applied Physics, chinese academy of {2., shanghai 2.Graduate school of chinese academy of {2., beijing, china

Liquid-gas phase transition is an essential phenomenon in nuclear *** this work,we calculate the shear viscosity to entropy density ratio(η/s)for an equilibrated system in intermediate energy heavy

关键词： BUU liquid-gas phase transition η /s

A Spectral Index for Estimating Soil Salinity in the Yellow River Delta Region of china Using EO-1 Hyperion Data

在线全文

cnki会议

学校读者我要写书评

暂无评论

Pedosphere 2010年第3期20卷 378-388页

作者： WENG Yong-Ling GONG Peng ZHU Zhi-Liang Department of Surveying and Mapping Engineering College of Transportation Southeast University Nanjing 210096(China) State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of the Chinese Academy ofSciences and Beijing Normal University Beijing 100101 (China) Department of Environment Science Policy and Management University of California Berkeley CA 94720 (USA) EROS Data Center U.S. Geological Survey Sioux Falls SD 57198 (USA)

Soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of china were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (SSI) was constructed from continuum-removed reflectance (CR-reflectance) at 2.52.and 2.03.nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the SSI and soil salt content (SSC). Then, a model for estimation of SSC with SSI was established using univariate regression and validation of the model yielded a root mean square error (RMSE) of 0.986 and an R2.of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMSE = 1.92. and R2.= 0.62.. These suggested that the satellite hyperspectral data had the potential for predicting SSC in a large area.

关键词： hyperspectral reflectance soil salt content spectral absorption features

Development of a middle and low latitude theoretical ionospheric model and an observation system data assimilation experiment

在线全文

学校读者我要写书评

暂无评论

Development of a middle and low latitude theoretical ionosph...

中国科学院地质与地球物理研究所2.08学术年会

作者： YUE XinAn~(1,2.3.,WAN WeiXing~(1+),LIU LiBo~1,LE HuiJun~1,CHEN YiDing~1 & YU Tao~(4,1) 1 Institute of Geology and Geophysics,chinese academy of {2.,beijing 10002.,china 2.Wuhan Institute of Physics and Mathematics,chinese academy of {2.,Wuhan 43.071,china 3.Graduate University of chinese academy of {2.,beijing 100049,china 4 National Center for Spaceweather,CMA,beijing 100081,china

On the basis of previous work,we develop a middle and low latitude theoretical ionospheric model in this paper,named Theoretical Ionospheric Model of the Earth in the Institute of Geology and Geophysics, chinese academy of {2.(TIME-IGGCAS).TIME-IGGCAS solves the equations of mass continuity, motion and energy of electron and ions self-consistently and uses an eccentric dipole field approximation to the Earth’s magnetic *** combine the Eulerian and Lagrangian approaches in the model and take account of the plasma E×B drift *** results reveal that the model is steady and credible and can reproduce most large-scale features of *** using TIME-IGGCAS,we carried out an observation system data assimilation *** results show that the E×B drift velocity can be accurately estimated by ingesting the observed foF2.and hmF2.into the model applying nonlinear least-square fit *** suggest that this work is of great significance in the development of ionospheric data assimilation model to give better nowcast and forecast of ionosphere.

关键词： ionosphere theoretical model data assimilation nonlinear least-square fit method

Approximating probabilities of correlated events

在线全文

cnki会议

学校读者我要写书评

暂无评论

Science china Mathematics 2010年第11期53卷 2937-2948页

作者： LI QiZhai1,2. ZHENG Gang3. LIU AiYi4, LI ZhaoHai2.5 & YU Kai2.1{3. of Mathematics and Systems Science, chinese {3. of sciences, beijing 100190, china 2.iostatistics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 2.892. USA 3.ffice of Biostatistics Research, National Heart, Lung and Blood Institute, Bethesda, MD 2.892. USA 4Biostatistics and Bioinformatics Branch, National Institute of Child Health and Human Development, Bethesda, MD 2.892. USA 5Department of Statistics, George Washington University, Washington, DC 2.052. USA 1. academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China2. Biostatistics Branch Division of Cancer Epidemiology and Genetics National Cancer Institute Bethesda MD 20892 USA3. Office of Biostatistics Research National Heart Lung and Blood Institute Bethesda MD 20892 USA4. Biostatistics and Bioinformatics Branch National Institute of Child Health and Human Development Bethesda MD 20892 USA5. Department of Statistics George Washington University Washington DC 20052 USA

Efron (1997) considered several approximations of p-values for simultaneous hypothesis testing. An extension of his approaches is considered here to approximate various probabilities of correlated events. Compared with multiple-integrations, our proposed method, the parallelogram formulas, based on a one-dimensional integral, not only substantially reduces the computational complexity but also maintains good accuracy. Applications of the proposed method to genetic association studies and group sequential analysis are investigated in detail. Numerical results including real data analysis and simulation studies demonstrate that the proposed method performs well.

关键词： case-control group sequential test genetic association studies MAX parallelogram