检索结果-南通市图书馆

Lookback time as a test for f(R) gravity in the Palatini approach

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2011年第11期11卷 1257-1265页

作者： Zhong-Xu Zhai and Wen-Biao Liu Department of Physics, institute of Theoretical Physics, beijing Normal University, beijing 100875, china Department of Physics Institute of Theoretical Physics Beijing Normal University Beijing 100875 China

We use the recently released data of lookback time (LT)-redshift relation, the cosmic microwave background shift parameter and the baryon acoustic oscillation measurements to constrain cosmological parameters of f (R) gravity in the Palatini formalism by considering the f (R) form of type (a) f (R) = R β/Rn and (b) f (R) = R + α ln R β. Under the assumption of a Friedmann-Robertson-Walker universe, we achieved the best fitting results of the free parameters (Ωm0, n) for (a) and (Ωm0, α) for (b). We find that current LT data can provide interesting and effective constraints on gravity models. Compared with other data, the LT constraints favor a smaller value of the non-relativistic matter energy density.

关键词： cosmology cosmic microwave background

The first-principles study on the doping effect of Re in Ni3Al

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2008年第7期18卷 861-866页

作者： Song Yu a,*, Chongyu Wanga,b, Tao Yua aCentral Iron and Steel Research institute, beijing 100081,{2. bDepartment of Physics, Tsinghua University, beijing 100084,{2. Central Iron and Steel Research institute Beijing 100081 China Department of Physics Tsinghua University Beijing 100084 China

Using first-principles density function for molecules method (DMol) and discrete variational method (DVM) based on the density functional theory, we studied the doping effect of Re in Ni3Al. The structure relaxation and the alloying energy show that Re has a strong Al site preference and leads to the local deformation, which is in agreement with the experimental results and other theoretical results. In addition, the charge density diffierence and the bond order show that Re can strongly enhance the interatomic interaction between the nearest neighbor atoms. From the density of states and the Pauli spectrum, we find that resonance states and localized states are induced by doping Re, and the doped Re atom forms the hybridized bond with the nearest neighbor atoms.

关键词： The first-principles Re Ni3Al

The Effect of Adjuvants on Penetration of beta-cypermethrin Through the Epidermis of Cabbage Leaf

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Agricultural sciences in china 2002年第3期1卷 313-318页

作者： WANG Yi, ZHANG Li-ta, ZHENG Fei-neng, CHEN Fu-liang and LIANG Wen-ping( institute of Plant Protection , chinese Academy of Agricultural {2. , beijing 100094 Center for Molecular Science , institute of Chemistry , The chinese Academy of {2. , beijing 100101 ) institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing 100094 Center for Molecular Science Institute of Chemistry The Chinese Academy of Sciences Beijing 100101

The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the penetration was positively correlated with both the concentration of adjuvant and the time after application, in a given range of treatment. A synergistic effect of two types of adjuvant on the penetration was found. Some physical properties of emulsions were determined. The change of the structures of the cabbage leaf surface by these adjuvants was observed from photomicrographs. The mechanism concerned with the effect of these adjuvants on the penetration of beta- cypermethrin through the cabbage leaf surface was tentatively discussed.

关键词： Adjuvant Nonionic surfactant Penetration beta-cypermethrin Synergistic effect

CONSENSUS CONTROL FOR LEADER-FOLLOWING MULTI-AGENT SYSTEMS WITH MEASUREMENT NOISES

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2010年第1期23卷 35-49页

作者： Cuiqin MA Tao LI Jifeng ZHANG School of Mathematical sciences Qufu Normal University Qufu 273165 China. Key Laboratory of Systems and Control Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China.

This work is concerned with consensus control for a class of leader-following multi-agentsystems (MASs).The information that each agent received is corrupted by measurement *** the impact of noises on consensus,time-varying consensus gains are adopted,based on whichconsensus protocols are *** using the tools of stochastic analysis and algebraic graph theory,asufficient condition is obtained for the protocol to ensure strong mean square consensus under the *** condition is shown to be necessary and sufficient in the noise-free ***,by using a common Lyapunov function,the result is extended to the switching topology case.

关键词： Consensus protocol leader-following multi-agent system stochastic noise.

Development of hydrogen energy and environment

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2006年第S1期 121-122页

作者： Mengkui TIAN1,2.3, Wenfeng SHANGGUAN1, Shijie WANG2. Ziyuan OUYANG2. Research Center for Combustion and Environment technology, Shanghai Jiaotong University, Shanghai 2.0030, china 2.State Key Laboratory of Environmental Geochemistry, {2. of Geochemistry, chinese Academy of sciences. Guiyang 550002. china 3 Graduate School of chinese Academy of sciences, beijing 100047, china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于曲线几何特征的地层参数识别算法

计算机工程与应用 2004年第27期40卷 228-229页

作者：李宗民刘玉杰于广斌石油大学(华东)计算机与通信工程学院中科院计算所智能信息处理重点实验室北京100080

论文给出了一种求地层特性参数的曲线匹配算法。首先对原始数据进行拟合,在不增加新条件的前提下计算出型值点上对应的一阶二阶导数;然后由模板曲线和拟合曲线段的渐缩线特征搜索出拟合曲线段在模板曲线上的对应段,由此求得相应的地层... 详细信息

论文给出了一种求地层特性参数的曲线匹配算法。首先对原始数据进行拟合,在不增加新条件的前提下计算出型值点上对应的一阶二阶导数;然后由模板曲线和拟合曲线段的渐缩线特征搜索出拟合曲线段在模板曲线上的对应段,由此求得相应的地层特性参数。实验表明,文中所叙述的方法是比较有效的。

关键词：曲线匹配模板曲线几何特征

Recruitment of stem cells by hepatocyte growth factor via intracoronary gene transfection in the postinfarction heart failure

在线全文

学校读者我要写书评

暂无评论

Science china(Life sciences) 2007年第6期50卷 748-752页

作者： YANG ZhiJian1, WANG Wei1, MA DongChao1, ZHANG YouRong2. WANG LianSheng1, ZHANG YuQing1, XU ShunLin1, CHEN Bo1, MIAO DengShun3, CAO KeJiang1 & MA WenZhu1 1 Department of Cardiovascular Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing 2.002., china 2.Department of Experimental Hematology, beijing {2. of Radiation Medicine, beijing 100850, china 3 Department of Experimental anatomy, Nanjing Medical University, Nanjing 2.002., china Department of Cardiovascular Medicine the First Affiliated Hospital of Nanjing Medical University Nanjing 210029 China Department of Experimental Hematology Beijing Institute of Radiation Medicine Beijing 100850 China Department of Experimental anatomy Nanjing Medical University Nanjing 210029 China

We aim to study the amelioration effect of adenovirus5-mediated human hepatocyte growth factor gene transfer on postinfarction heart failure in swine model. Twelve Suzhong young swine were randomly divided into 2.groups of 6 pigs each: Ad5-HGF group and mock-vector Ad5 group. Four weeks after ligation of the left anterior descending coronary artery, Ad5-HGF was intracoronarily transferred into the myocardium. Simultaneously, gate cardiac perfusion imaging was performed to evaluate the heart function. Three weeks later, gate cardiac perfusion imaging was performed again, then the hearts were removed and sectioned for immunohistochemical examination to illustrate the effects of Ad5-HGF on infarcted myocardium. The expression of HGF was examined by ELISA. The results were: (1) compared with the mock-vector Ad5 group, high expression of human HGF was observed in the myocardium of Ad5-HGF group; (2. in the Ad5-HGF group, the number of CD117+ cells co-expressing c-Met per mm2.was significantly larger; (3) the improvement in LVEF was greater in the Ad5-HGF group than in the mock-vector Ad5 group. We concluded that: (1) high expression of human HGF was observed in the myocardium through intracoronary gene transfection; (2. HGF can improve the mobilization of CD117+/c-Met+ stem cells into ischemic myocardium. The amelioration effect of HGF on postinfarction heart failure could not be limited to stimulating angiogenesis, anti-apoptosis, anti-fibrosis, but was also involved in the recruitment of stem cells into myocardium.

关键词： gene therapy, stem cells, postinfarction heart failure

Adult congenital diaphragmatic hernia of the liver: a rare case report

在线全文

学校读者我要写书评

暂无评论

Science china(Life sciences) 2010年第2期53卷 204-206页

作者： LIU LiGuo1,2.XU YiYao1,MAO YiLei1,SANG XinTing1,YANG ZhiYing1,LU Xin1,ZHONG ShouXian1 & HUANG JieFu1 1 Department of Liver Surgery,Peking Union Medical College Hospital,beijing 100730,china 2.Department of Abdominal Surgery,Cancer {2. and Hospital,chinese Academy of Medical Science and Peking Union Medical College,beijing 10002.,china. 1. Department of Liver Surgery Peking Union Medical College Hospital Beijing 100730 China2. Department of Abdominal Surgery Cancer Institute and Hospital Chinese Academy of Medical Science and Peking Union Medical College Beijing 100021 China

Congenital diaphragmatic hernia (CDH), which mainly occurs in the newborn or in childhood with severe respiratory distress and high mortality, is rarely found in adult, especially for those uncommon right CDH [1–4]. ... 详细信息

关键词： case In Adult congenital diaphragmatic hernia of the liver a rare case report

PERIODIC SOLUTIONS TO A KIND OF NEUTRAL FUNCTIONAL DIFFERENTIAL EQUATION WITH MULTIPLE DELAYED ARGUMENTS

在线全文

学校读者我要写书评

暂无评论

Annals of Differential Equations 2008年第3期24卷 253-260页

作者： Guo Lixiang1, Lu Shiping1, Du Bo2. Liang Feng1 (1. Dept. of Math., Anhui Normal University, Wuhu 2.1000, Anhui 2. Dept. of Math., beijing institute of {2., beijing 100081)

By employing Mawhin’s continuation theorem and some analytic techniques, we study the existence of periodic solutions to a kind of neutral functional differential equation with delays. Our results generalize the corr... 详细信息

关键词： neutral delays periodic solutions Mawhin’s continuation theorem