检索结果-南通市图书馆

Metal abundance and kinematical properties of the M81 globular cluster system

Research in Astronomy and Astrophysics 2013年第4期13卷 399-410页

作者： Jun Ma Zhen-Yu wu Tian-Meng Zhang Song Wang Zhou Fan Jiang-hua wu Hu Zou Cui-hua Du Xu Zhou Qi-Rong Yuan National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences Graduate University of Chinese Academy of Sciences Department of Astronomy Beijing Normal University College of Physical Sciences Graduate University of Chinese Academy of Sciences Department of Physics Nanjing Normal University

We present metal abundance properties of 144 globular clusters associated with M81. These globulars represent the largest globular cluster sample in M81 till now. Our main results are： the distribution of metallicities is bimodal, with metallicity peaks at [Fe/H] -1.51 and -0.58, and the metal-poor globular clusters tend to be less spatially concentrated than the metal-rich ones; the metal-rich globular clusters in M81 do not demonstrate a centrally concentrated spatial distribution like the metalrich ones in M31 do; like our Galaxy and M31, the globular clusters in M81 have a small radial metallicity gradient. These results are consistent with those obtained from a small sample of M81 globular clusters. In addition, this paper shows that there is evidence that a strong rotation of the M81 globular cluster system around the minor axis exists, and that rotation is present in the metal-rich globular cluster subsample, but the metal-poor globular cluster subsample shows no evidence of rotation. The most significant difference between the rotation of the metal-rich and metal-poor globular clusters occurs at intermediate projected galactocentric radii. Our results confirm the conclusion of Schroder et al. that M81＇s metal-rich globular clusters at intermediate projected radii are associated with a thick disk of M81.

关键词： galaxies: individual (M81) -galaxies: star clusters globular clusters:general

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A New Triterpene from Cephalomappa sinensis

引用

Chinese Chemical Letters 2001年第6期12卷 507-508页

作者： Wen Li MEI Yun Bao MA Shao hua wu Hao Fu DAI Da Gang wu Laboratory of Phytochemistry Kunming Institute of BotanyAcademia SinicaKunming 650204

A new triterpene 1, 1 beta, 2 alpha, 3 beta -trihydroxylup-20 (29) -ene was isolated from Cephalomappa sinensis. The structure was elucidated mainly on the basis of 1D and 2D NMR spectral means.

关键词： Triterpene Cephalomappa sinensis Euphorbiaceae

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Control design and comprehensive stability analysis of acrobots based on Lyapunov functions

引用

Journal of Central South University of Technology 2005年第Z1期12卷 210-216页

作者： LAI Xu-zhi wu Yun-xin SHE Jin-hua wu Min School of Information Science and Engineering Central South University Changsha 410083 China School of Mechanical and Engineering Central South University Changsha 410083 China School of Bionics Tokyo University of Technology 1404 - 1 Katakura Hachioji Tokyo 192 - 0982 Japan School of Information Science and Engineering Central South University Changsha 410083 China

A design method for controllers and a comprehensive stability analysis for an acrobat based on Lyapunov functions are presented. Three control laws based on three Lyapunov functions are designed to increase the energy so as to move the acrobot into the unstable inverted equilibrium position, and solve the problem of posture and energy. The concept of a non-smooth Lyapunov function is employed to analyze the stability of the whole system. The validity of this strategy is demonstrated by simulations.

关键词： stability Lyapunov function acrobot fuzzy control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A New 24, 30-Dinortriterpenoid from Paeonia delavayi

引用

Chinese Chemical Letters 2001年第4期12卷 345-346页

作者： Shao hua wu Xiao Dong LUO Yun Bao MA Xiao Jiang HAO Da Gang wu Laboratory of Phytochemistry Kunming Institute of BotanyChinese Academy of SciencesKunming 650204

A new triterpenoid. 3 beta. 4 beta. 23-trihydroxy-24, 30-dinorolean-12. 20(29)-dien-28-oic acid. together with five known compounds. 2 alpha. 3 beta. 23-trihydroxy-12-oleanen-28-oic acid-beta -D-glucose glucopyranosyl ester. palbinone. 2-hydroxy-benzoic acid, vanillic acid. syringic acid. were isolated from the roots of Paeonia delavayi Franch. Their structures were characterized by spectral analysis.

关键词： Paeonia delavayi Franch. Paeoniaceae triterpenoid 3 beta,4 beta, 23-trihydroxy-24, 30-dinorolean-12,20(29)-dien-28-oic acid

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cardiopulmonary bypass induced microcirculatory injury of the small bowel in rats

引用

World Journal of Gastroenterology 2009年第25期15卷 3166-3172页

作者： Guo-hua Dong Chang-Tian Wang Yun Li Biao Xu Jian-Jun Qian Hai-Wei wu hua Jing Department of Cardiothoracic Surgery Jinling Hospital Clinical Medicine School of Nanjing University Nanjing 210002 Jiangsu Province China

AIM： To investigate microvascular injury quantitatively in the small bowel with respect to cardiopulmonary bypass （CPB） and related mechanisms. METHODS： In 10 male SD rats, normothermic CPB was established and continued with a flow rate of 100-150 mL/kg per minute for 60 min, while another 10 sham-operated animals served as controls. An approximate 10-cm loop of the terminal ileum was exteriorized for observation by means of intravital fluorescence microscopy. The small bowel microcirculatory network including arterioles, capillaries, and collecting venules was observed prior to CPB, CPB 30 min, CPB 60 min, post-CPB 60 min and post-CPB 120 rain. The intestinal capillary perfusion, microvascular permeability and leukocyte adherence were also measured. RESULTS： The systemic hemodynamics remained stable throughout the experiment in both groups. In CPB animals, significant arteriolar vasoconstriction, blood velocity reduction and functional capillary density diminution were found. As concomitances, exaggerated albumin extravasation and increased leukocyte accumulation were also noted. These changes were more pronounced and there were no signs of restitution at the end of the observation period. CONCLUSION： CPB induces significant microcirculatory injury of the small bowel in rats. The major underlying mechanisms are blood flow redistribution and generalized inflammatory response associated with CPB.

关键词： Cardiopulmonary bypass Functional capillary density Intestinal microcirculation Intravital microscopy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Image Registration Based on SOFM Neural Network Clustering 36

Image Registration Based on SOFM Neural Network Clustering

引用

第36届中国控制会议

作者： Lin-Lin Ge Yun-hua wu Bing hua Zhi-Ming Chen Lin Chen College of Astronautics Nanjing University of Aeronautics and Astronautics

ISBN: (纸本)9781538629185

Spacecraft autonomous navigation method based on remote sensing image is a novel method which has been put into practical use in recent ***,with the restricted computation resource onboard,this method still needs to look for a better way to improve its speed to satisfy real-time *** to the problem above,this paper proposed an alternate method to faster image registration progress with the combination of SURF（Speed-Up Robust Features） and SOFM（Self-Organizing Feature Map）.SURF is a sophisticated algorithm which is invariant to scaling and rotation,and SOFM is a kind of neural network which is used for clustering analysis in this ***,a new algorithm called Similarity-Clustering Algorithm（SCA） is presented to analysis the result of ***,a performance index called Precision is defined to determine the best value of Epoch for SOFM neural network *** experimental results demonstrate that the proposed approach for registration has good adaptability for real-time practical application.

关键词： Image Registration Self-Organizing Feature Maps Clustering Analysis Neural Network

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Evaluation of Eco-Environmental Frangibility Based on Remote Sensing and Geographic Information System

引用

wuhan University Journal of Natural Sciences 2007年第4期12卷 715-720页

作者： wu hua TAO Heping LU Yuan Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 Sichuan China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The eco-environmental frangibility is studied by choosing the factors of land use class change and vegetation cover rate, and the equation of eco-environmental frangibility and its evaluation system are established based on remote sensing （RS） and geographic information system technology （GIS）. Four different years of TM images are selected to calculate land use change grads and vegetation cover rate, and the relationship between the two factors and eco-environment frangibility index are build, taking Fuzhou as an example. The character of times change and space distribution of eco-environment frangibility are described. The result indicates the area of eco-environment frangibility increased 2.6% in Fuzhou during twelve years, and expands from the region between infield and forest land to forest land in space distribution.

关键词： eco-environment frangibility RS (remote sensing) land use vegetation coverage rate

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic Drought Monitoring in Guangxi Using Revised Temperature Vegetation Dryness Index

引用

wuhan University Journal of Natural Sciences 2007年第4期12卷 663-668页

作者： LU Yuan TAO Heping wu hua Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of Sciences / Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 Sichuan China Faculty of Resources and Environmental Sciences Guangxi Teachers Education University Nanning 530001 Guangxi China

Moderate resolution imaging spectroradiometer （MODIS） data are very suitable for vast extent, long term and dynamic drought monitoring for its high temporal resolution, high spectral resolution and moderate spatial resolution. The composite Enhanced Vegetation Index （EVI） and composite land surface temperature （Ts） obtained from MODIS data MOD11A2 and MOD13A2 were used to construct the EVI-Ts space. And Temperature Vegetation Dryness Index （TVDI） was calculated to evaluate the agriculture drought in Guangxi province, China in October of 2006. The results showed that the drought area in Guangxi was evidently increasing and continuously deteriorating from the middle of September to the middle of November. The TVDI, coming from the EVI-Ts space, could effectively indicate the spatial distribution and temporal evolution of drought, so that it could provide a strong technical support for the forecasting agricultural drought in south China.

关键词： moderate resolution imaging spectroradiometer (MODIS) enhanced vegetation index land surface temperature temperature vegetation dryness index

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Change of choline compounds in sodium selenite-induced apoptosis of rats used as quantitative analysis by in vitro 9.4T MR spectroscopy

引用

World Journal of Gastroenterology 2008年第24期14卷 3891-3896页

作者： Zhen Cao Lin-Ping wu Yun-Xia Li Yu-Bo Guo Yao-Wen Chen Ren-hua wu Departmen't of Medical Imaging The S'econdAffiliated Hospital Shantou University Medical CollegeShantou 515041 Guangdong Province China Multidisciplinary Research Center ShantouUniversity Shantou 515041 Guangdong Province China

AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar rats were randomly divided into two groups. The rats in the treatment group were intraperitoneally injected with sodium selenite and the control group with distilled water. All rats were sacrifi ced and the livers were dissected. 1H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer. Spectra were processed using XWINNMR and MestRe-c 4.3. HE and TUNEL staining was employed to detect and confi rm the change of liver cells. RESULTS: Good 1H-MR spectra of perchloric acid extract from liver tissue of rats were obtained. The conventional metabolites were detected and assigned. Concentrations of different ingredient choline compounds in treatment group vs control group were as follows: total choline compounds,5.08 ± 0.97 mmol/L vs 3.81 ± 1.16 mmol/L (P = 0.05); and free choline,1.07 ± 0.23 mmol/L vs 0.65 ± 0.20 mmol/L (P = 0.00). However,there was no statistical signif icance between the two groups. The hepatic sinus and cellular structure of hepatic cells in treatmentgroup were abnormal. Apoptosis of hepatic cells was confi rmed by TUNEL assay. CONCLUSION: High dose selenium compounds can cause the rat liver lesion and induce cell apoptosis in vivo. High resolution 1H-MRS in vitro can detect diversified metabolism. The changing trend for different ingredient of choline compounds is not completely the same at early period of apoptosis.

关键词： Apoptosis of liver cell Choline compounds Sodium selenite In vitro ^1H-MRS Quantitative analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

NMDA receptor signaling:death or survival?

引用

Frontiers in Biology 2011年第6期6卷 468-476页

作者： Tong LUO Wei-hua wu Bo-Shiun CHEN Institute of Molecular Medicine and Genetics Department of NeurologyGeorgia Health Sciences UniversityAugustaGA 30912USA

Glutamate-induced neuronal damage is mainly caused by overactivation of N-methyl-D-aspartate(NMDA)***,normal physiological brain function and neuronal survival require adequate activation of NMDA *** have revealed that NMDA receptor-induced neuronal death or survival is mediated through distinct subset of NMDA receptors triggering different intracellular signaling *** we discuss recent advances in the characterization of NMDA receptors in neuronal protection,emphasizing subunit-specific role,which contributes to temporal-spatial distribution,subcellular localization and diverse channel properties of NMDA receptors.

关键词： NMDA receptors glutamate excitotoxicity ischemia neuroprotection

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：