检索结果-南通市图书馆

A template of rat brain based on fMRI T2. imaging

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第6期15卷 502-506页

作者： HU Zhenghui1, WU Yigen2. WANG Xiaochuan3, WANG Jianzhi3, CHEN Feiyan1 and TANG Xiaowei1*(1. Department of Physics and Bio-X laboratory, Zhejiang University, Hangzhou 31002., china 2. {2. of high energy Physics and key laboratory of Nuclear Analysis Techniques, chinese academy of sciences,beijing 100039, china 3. Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, china) Department of Physics and Bio-X laboratory Zhejiang University Hangzhou 310027 China key laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100039 China Department of Pathophysiology Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China

The development of functional magnetic resonance imaging (fMRI) technology has made it possible to carry out functional brain imaging experiments in small animals. Usually, group data is required to form the assessment of population, which can not only increase the sensitivity of the overall experiment, but also allow the generalization of the conclusion to the whole population. In order to average the signals of functional brain images from different subjects, it is necessary to put all the mapping images into the same standard space (template image). However, up to now, most animal brain templates remain unavailable and it must be done by ourselves. In this study, a template image based on the brains of eight male Wistar rats is obtained, and it is successfully used in our present Alzheimer disease (AD)-like rat model studies as template for spatially normalizing images to the same stereotaxical space. The fMRI results processed with statistical parametric mapping (SPM99) software are in agreement with the results from immunohistochemical experiment, which proves that this method is universally applicable to the pathologic models of other small animals and to human brain lesion studies.

关键词： fMRI animal model atlas template normalization T*2.

The effects of shock wave and quasi-traveling wave in the mechanical impact test

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第9期53卷 2535-2541页

作者： WU Mei1,5,SUN ZhongFeng2.ZHANG LuMei3,CHEN Yong1 & JI LinHong4 1 institute of high {2. Physics,chinese academy of sciences,beijing 100049,china 2.School of Mathematical sciences,Peking University,beijing 100871,china 3 high School of Central University for Nationalities,beijing 100081,china 4 institute of Mechanical Design,Department of Precision Instruments and Mechanology,Tsinghua University,beijing 100084,china 5 academy of Opto-electronics,chinese academy of sciences,beijing 100190,china institute of high {2. Physics Chinese Academy of Sciences Beijing China academy of Opto-electronics Chinese Academy of Sciences Beijing China School of Mathematical sciences Peking University Beijing China high School of Central University for Nationalities Beijing China institute of Mechanical Design Department of Precision Instruments and Mechanology Tsinghua University Beijing China

It is well-known that the numerical value is always larger than the measured value,amounting to many times,if we calculate the stress of the specimen in the impulse test using the NASTRAN and ANSYS (N-A) *** believe that the impact induces shock wave or quasi-traveling wave in the specimen,which can qualitatively explain the discrepancy of the two *** order to verify it,the Lax-Friedrichs (L-F) scheme is taken to simulate the transmission of shock wave and quasi-traveling wave in *** results show that the action area of the stress wave is small and the action time is very short,so the resulting stress and actual work are not *** addition,the distribution of the impact values obtained by the numerical simulation is in accordance with the trend of the measured impact values.

关键词： aerospace environment test shock wave quasi-traveling wave

fMRI time series analysis based on stationary wavelet and spectrum analysis

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第11期16卷 1171-1176页

作者： ZHI Lianhe~ 1,2.3 , ZHAO Xia~4, SHAN Baoci~1**, PENG Silong~5, YAN Qiang~1, YUAN Xiuli~1 and TANG Xiaowei~ 1,6 (1. key laboratory of Nuclear Analysis Techniques, {2. of high energy Physics, chinese academy of sciences, beijing 100049, china 2. Graduate School of chinese academy of sciences, beijing 100049, china 3. Department of Physics, Zhoukou Normal University, Zhoukou 466100, china 4. Research Imaging Center, University of Texas Health Science Center, San Antonio, Texas 782.9, USA 5. National ASIC Design and Engineering Center, {2. of Automation, chinese academy of sciences, beijing 100049, china 6. Department of Physics, Zhejiang University, Hangzhou 31002., china) key laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China Graduate School of chinese academy of sciences Beijing 100049 China Department of Physics Zhoukou Normal University Zhoukou 466100 China Research Imaging Center University of Texas Health Science Center San Antonio TX 78229 United States National ASIC Design and Engineering Center Institute of Automation Chinese Academy of Sciences Beijing 100049 China Department of Physics Zhejiang University Hangzhou 310027 China

The low signal to noise ratio (SNR) of functional MRI (fMRI) prefers more sensitive data analysis methods. Based on stationary wavelet transform and spectrum analysis, a new method with high detective sensitivity was developed for analyzing fMRI time series, which does not require any prior assumption of the characteristics of noises. In the proposed method, every component of fMRI time series in the different time-frequency scales of stationary wavelet transform was discerned by the spectrum analysis, then the components from noises were removed using the stationary wavelet transform, finally the components of real brain activation were detected by cross-correlation analysis. The results obtained from both simulated and in vivo visual experiments illustrated that the proposed method has much higher sensitivity than the traditional cross-correlation method.

关键词： fMRI stationary wavelet transform spectrum analysis data analysis.

Zircon and apatite fission track analyses on mineralization ages and tectonic activities of Tuwu-Yandong porphyry copper deposit in northern Xinjiang, 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

Science china Earth sciences 2007年第12期50卷 1787-1795页

作者： YUAN WanMing1,BAO ZengKuan2.DONG JinQuan2.GUO ZhaoJie3 & DENG Jun1 1 State key laboratory of Geological Processes and Mineral Resources,{2. University of Geosciences,beijing100083,{2. 2.laboratory of Nuclear Analysis Techniques,institute of high energy Physics,chinese academy of sciences,beijing 100039,{2. 3 Department of Geology,Peking University,beijing 100871,{2. State key laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing China laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing China Department of Geology Peking University Beijing China

The mineralization ages reported in the past in the Tuwu-Yandong copper district not only are different,but also fall into the Hercynian *** study has achieved 9 zircon and 7 apatite fission track analysis *** zircon fission track ages range from 158 Ma to 2.9 Ma and the apatite ages are between 64 Ma and 140 *** mineralization accords with the regional tectonics in the copper *** consider that the zircon fission track age could reveal the mineralization age based on annealing zone temperature of 140―300℃ and retention temperature of ～2.0℃ for zircon fission track,and metallogenetic temperature of 12.―350℃ in this ore *** three mineralization epochs have been identified,i.e.,2.9―2.6 Ma,2.2.2.0 Ma and 165―158 Ma,and indicate occurrence of the min-eralization in the Indosinian and Yanshan *** to apatite fission track ages,the three tectonic-mineralizing epochs are 140―132.Ma,109―97 Ma and 64 Ma,which means age at about 100℃ after the *** three epochs lasted 146 Ma,108 Ma and about 100 Ma from ～2.0℃ to ～100℃ and trend decrease from early to *** is shown by the fission track modeling that this district underwent three stages of geological thermal histories,stable in Cretaceous and cooling both before Cretaceous and after 2. Ma.

关键词： mineralization age, tectonic epoch, fission track, zircon, apatite, Tuwu-Yandong, Xinjiang

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2. DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, XUE Qikun1 & ZHANG Ze2. 4 1. State key laboratory for Surface Physics, {2. of Physics, chinese academy of sciences, beijing 100080, china 2. laboratory of Electron Microscopy, {2. of Physics, chinese academy of sciences, beijing 100080, china 3. College of Physics and Engineering, Qufu Normal University, Qufu 2.3165, china 4. beijing University of Technology, beijing 10002., china State key laboratory for Surface Physics Institute of Physics Chinese Academy of Sciences Beijing China College of Physics and Engineering Qufu Normal University Qufu China laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China beijing University of Technology Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high {2. electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Adsorption of zinc on manganite(γ-MnOOH): particle concentration effect and adsorption reversibility

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental sciences 2004年第4期16卷 627-630页

作者： QIN Yan-wen1, PAN Gang 1,2., ZHANG Ming-ming1, LI Xian-liang1 (1. State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental {2., chinese academy of sciences, beijing 100085, china. 2. Qingdao University of Science & Technology, Qingdao 2.6042. china) State key laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

The adsorption and desorption processes of Zn(Ⅱ) on γ-MnOOH as a function of particle concentrations(C p) were studied. An obvious C p effect was observed in this adsorption system. The degree of adsorption hysteresis increased greatly with the increasing of C p, indicating that the extent of the real metastable-equilibrium states deviating from the ideal equilibrium state was enhanced with the increasing of C p. The C p-reversibility relationship confirmed the metastable-equilibrium adsorption(MEA) inequality(Pan, 1998a), which was the core formulation of the MEA theory. Because the MEA inequality was based on the basic hypothesis of MEA theory that adsorption density Γ is not a state variable, the C p-reversibility relationship gave indirect evidence to the basic hypothesis of MEA theory.

关键词： zinc γ-MnOOH adsorption reversibility

Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2.& LI YaoKun3,4 1National Marine Environmental Forecasting Center, beijing 100081, china 2.irst {2. of Oceanography, State Oceanic Administration, Qingdao 2.6061, china 3State key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, {2. of Atmospheric Physics, chinese academy of sciences, beijing 10002., china 4Graduate University of chinese academy of sciences,{12., china National Marine Environmental Forecasting Center Beijing China First institute of Oceanography State Oceanic Administration Qingdao China State key laboratory of Numerical Modeling for Atmospheric {2. and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

Analytical method of radiation by a wave energy device with dual rectangular floating bodies

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2010年第3期29卷 106-115页

作者： WANG Wensheng YOU Yage ZHANG Yunqiu WU Bijun YE Yin Guangzhou institute of energy Conversion Chinese Academy of Sciences Guangzhou 510640 China key laboratory of Renewable {2. and Gas Hydrate Chinese Academy Sciences Guangzhou 510640 China Graduate University Chinese Academy of Sciences Beijing 100049 China

The system with one floating rectangular body on the free surface and one submerged rectangular body has been applied to a wave energy conversion device in water of finite depth. The radiation problem by this device on a plane incident wave is solved by the use of an eigenfunction expansion method, and a new analytical expression for the radiation velocity potential is obtained. The wave excitation force is calculated via the known incident wave potential and the radiation potential with a theorem of Haskind employed. To verify the correctness of this method, an example is computed respectively through the bound element method and analytical method. Results show that two numerical methods. are in good agreement, which shows that the present method is applicable. In addition, the trends of hydrodynamic coefficients and wave force are analyzed under different conditions by use of the present analytical method.

关键词： wave energy device hydrodynamic coefficients wave force analytical method

Low-temperature magnetic properties of horse spleen ferritin

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2010年第27期55卷 3174-3180页

作者： TIAN LanXiang 1,2.CAO ChangQian 1,2.LIU QingSong 1,2.&PAN YongXin 1,2.1key laboratory of the Earth’s Deep Interior,{2. of Geology and Geophysics,chinese academy of sciences,beijing 10002.,china 2.ranco-chinese Biomineralization and Nano-structures laboratory,beijing 10002.,china key laboratory of the Earth’s Deep Interior Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Franco-chinese Biomineralization and Nano-structures laboratory Beijing China

The magnetic properties of the antiferromagnetic cores in ferritin are of importance in the construction and improvement of ferritin-based magnetic resonance imaging systems and their application to environmental *** this study,we carry out integrated magnetic and transmission electron microscopy analyses of horse spleen ferritin(HoSF)to understand the relationships between the magnetic behavior of HoSF and temperature,applied field and grain-size *** R-value from the Wohlfarth-Cisowski test for the investigated sample at 5 K was 0.46,indicating very weak magnetostatic interactions among the nanoparticles of *** nanoparticles of HoSF show superparamagnetic properties at room temperature,while below the blocking temperature of Tb≈12.K it has a net magnetic moment that comes from the uncompensated spins of the nanoparticle surface or *** thermal relaxation process of HoSF follows the Néel-Arrhenius *** low-temperature AC susceptibility data,we calculated the effective magnetic anisotropy energy Ea=(5.52.0.16)×10-2. J;the effective magnetic anisotropy energy constant Keff=(4.65±0.14)×10 4 J/m3 and the pre-exponential frequency factor f0 =(4.52.2.93)×1011 *** values are useful in understanding the magnetic behavior of the antiferromagnetic nanoparticles and their potential application in biomedical technology.

关键词：马脾铁蛋白低温度磁性质透射电子显微镜磁各向异性常数纳米粒子生物医学技术交流磁化率