检索结果-南通市图书馆

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2. CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 Key Laboratory of Beam Technology & Materials Modification of the Ministry of Education, institute of Low energy {2. physics, beijing Normal University, beijing 100875, China 2.beijing Radiation Center, beijing 100875, China 3 Laboratory of Optical physics, institute of physics, Chinese Academy of Sciences, beijing 100080, China 4 Key Laboratory of Advanced Materials of the Ministry of Education, {12. of Materials Science and Engineering, Tsinghua University, beijing 100084, China 5 beijing National Center for Electron Microscopy, Tsinghua University, beijing 100084, China 1. Key Laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China 2. beijing Radiation Center Beijing 100875 China 3. Laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China 4. Key Laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing 100084 China 5. beijing National Center for Electron Microscopy Tsinghua University Beijing 100084 China

The LaMn1-xTexO3+δ (x=0.1, 0.2. 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2. and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2., Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2. and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2. and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

Anomalous Phenomena in E<18 keV Hydrogen Ion Beam Implantation Experiments on Pd and Ti

在线全文

学校读者我要写书评

暂无评论

Chinese journal of nuclear physics 1997年第4期19卷 244-249页

作者： Wang Tieshan~(1) Piao Yubo~(2. Hao Jifang~(1) Wang Xuezhi~(2. Jin Genming~(1) Niu Zhanqi~(2. (1)institute of Modern physics,the Chinese Academy of Sciences,Lanzhou 730000 (2.{2. of Modern physics of Lanzhou University,Lanzhou 730000 中科院近代物理所甘肃兰州兰州大学现代物理系甘肃兰州

Implantation experiments of low energy（1 keVmax1.2.mA/cm2.and lowbeam density(Jmin0.02.mA/cm2..Palladium and titanium foils（plates）are bombarded withproton and deuteron beams in order to compare the atomic and nucl... 详细信息

Implantation experiments of low energy（1 keVmax1.2.mA/cm2./sup>)and lowbeam density(Jmin0.02.mA/cm2./sup>).Palladium and titanium foils（plates）are bombarded withproton and deuteron beams in order to compare the atomic and {2. interactions between dif-ferent ion beams.X-ray and charged particles are measured,and neutron and gamma doses arealso monitored during the implantation *** anomalous peak in X-spectra,whoseenergy is about four times the beam energy,is observed during the high beam density *** peak moves from about 40 keV to 62.keV and FWHM reduces rapidly,while thebeam energy and intensity *** wide peak with over twice the beam energy is mea-sured in experiment with low beam *** is located between 16 keV and 30 keV,and itspeak energy increases with the increase of implantation dose（implantation time）.Some anoma-lous intensities of neutrons correlated with a charged particle peak（2.93,3.85 MeV）are alsoobserved in the deuteron-palladium *** highest neutron intensity reaches about8×104 n/s,while the beam energy and intensity are about 15 keV and 1.0 mA,respectively.

关键词： Hydrogen ion beam Low energy Implantation Palladium and titanium foils

Correlation of Behavior Changes and BOLD Signal in Alzheimer-like Rat Model

在线全文

学校读者我要写书评

暂无评论

Acta Biochimica et Biophysica Sinica 2004年第12期36卷 803-810页

作者： Zheng-Hui HU#, Xiao-Chuan WANG1#, Li-Yun LI3, Mai-Li LIU3, Rong LIU1, Zhiqun LING1, Qing TIAN1, Xiao-Wei TANG, Yi-Gen WU2., and Jian-Zhi WANG1* department of physics and Bio-X disciplinary Laboratory, Zhejiang University, Hangzhou 31002.,China 1 department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China 2.3} of High energy physics and Key Laboratory of nuclear Analysis Techniques, Chinese Academy of Sciences, P.O. Box 918, beijing 100039, China 3Wuhan institute of physics and Mathematics, State Key Laboratory of Magnetic Resonance and atomic and Molecular physics, Chinese Academy of Sciences, Wuhan 430071, China department of physics and Bio-X disciplinary Laboratory Zhejiang UniversityHangzhou 310027China department of Pathophysiology Tongji Medical College Huazhong University of Science and TechnologyWuhan 430030 China Wuhan institute of physics and Mathematics State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Chinese Academy of SciencesWuhan 430071 China institute of High energy {2. and Key Laboratory of nuclear Analysis Techniques Chinese Academy of SciencesP.O. Box 918 Beijing 100039 China

To explore a potential means for the early diagnosis of Alzheimer disease, we studied the relationship of resting T2. signal and tau hyperphosphorylation/spatial memory deficit. The rat model with tau hyperphosphorylation and spatial memory deficit was established by bilateral hippocampi injection of isoproterenol (IP). Then, the correlative alteration between resting T2. signal and spatial memory retention was assessed with blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) study and Morris Water Maze test, and Western blot was employed to confirm tau hyperphosphorylation. The analysis showed following results. (1) Tau phosphorylation at Ser396/Ser404 and Ser199/Ser2.2.was signifi- cantly increased in IP-injected rats as detected by PHF-1 and tau-1, respectively. (2. An AD-like spatial memory retention disturbance was induced at 2. h after isoproterenol injection. (3) A sensitivity threshold of resting T2. signal intensity, which separated the IP-treated rats from vehicle control, was obtained by applying linear regression analysis, and an estimated sensitivity statistical threshold was at 32.62. These results suggest that resting T2. signal may serve as a noninvasive quantitative marker in predicting AD-like spatial memory deficits and tau hyperphosphorylation.

关键词： Alzheimer disease (AD) functional magnetic resonance imaging (fMRI) isoproterenol (IP) Morris Water Maze diagnosis

X（3872. and Bound State Problem of D0*0（0 D*0）

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

原子核物理评论 2009年第S1期 16-21页

作者： LIU Yan-rui1,LIU Xiang2.3,DENG Wei-zhen2.(1 institute of High energy {2.,Chinese Academy of Sciences,beijing 100049,China 2.department of {2.,Peking University,beijing 100871,China 3 Centro de Física Terica,Departamento de Física,Universidade de Coimbra,P-3004-516,Coimbra,Portugal)

We have performed a dynamical calculation of the bound state problem of D0D*0 by considering the pion and sigma meson exchange potential. Our preliminary analysis disfavors the molecular interpretation of X(3872. if we use the experimental D*Dπ coupling constant g=0.59 and a reasonable cutoff around 1 GeV,which is the typical hadronic scale. In contrast,there probably exists a loosely bound S-wave BB* molecular state. Such a molecular state would be rather stable since its dominant decay mode is the radiative decay through B*→Bγ.

关键词： X(3872. bound state molecule

Random Phase Approximation in Relativistic Approach

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

原子核物理评论 2009年第S1期26卷 49-54页

作者： MA Zhong-yu1,2.YANG Ding1,TIAN Yuan1,CAO Li-gang2.3(1 China institute of atomic {2.,beijing 102.13.China 2.Center of Theoretical nuclear physics,National Laboratory of Heavy Ion Research Facility in Lanzhou,Lanzhou 730000,China 3 institute of Modern physics,Chinese Academy of Sciences,Lanzhou 730000,China) China institute of atomic {2. Beijing 102413China Center of Theoretical nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China China institute of atomic {2. Beijing 102413China Center of Theoretical nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China institute of Modern physics Chinese Academy of SciencesLanzhou 730000China

Some special issues of the random phase approximation(RPA) in the relativistic approach are reviewed. A full consistency and proper treatment of coupling to the continuum are responsible for the successful application of the RPA in the description of dynamical properties of finite nuclei. The fully consistent relativistic RPA(RRPA) requires that the relativistic mean filed (RMF) wave function of the nucleus and the RRPA correlations are calculated in a same effective Lagrangian and the consistent treatment of the Dirac sea of negative energy states. The proper treatment of the single particle continuum with scattering asymptotic conditions in the RMF and RRPA is discussed. The full continuum spectrum can be described by the single particle Green's function and the relativistic continuum RPA is established. A separable form of the paring force is introduced in the relativistic quasi-particle RPA.

关键词： fully consistent RRPA coupling to the continuum pairing correlation

How random are matrix elements of the nuclear shell model Hamiltonian?

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1477-1481页

作者： SHEN JiaJie1 & ZHAO YuMing1,2.3,4 1 department of physics,Shanghai Jiao Tong University,Shanghai 2.02.0,China 2.Center of Theoretical {2. physics,National Laboratory of Heavy Ion Accelerator,Lanzhou 730000,China 3 Nishina Center,institute of Physical Chemical Research(RIKEN),Hirosawa 2.1,Wako-shi,Saitama 351-0198,Japan 4 CCAST,World Laboratory,beijing 100080,China department of physics Shanghai Jiao Tong University Shanghai 200240 China Center of Theoretical nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou 730000 China Nishina Center Institute of Physical Chemical Research (RIKEN) Hirosawa 2-1 Wako-shi Saitama 351-0198 Japan World Laboratory CCAST Beijing 100080 China

In this paper we study the general behavior of matrix elements of the nuclear shell model *** find that nonzero off-diagonal elements exhibit a regular pattern,if one sorts the diagonal matrix elements from smaller to larger *** correlation between eigenvalues and diagonal matrix elements for the shell model Hamiltonian is more remarkable than that for random matrices with the same distribution unless the dimension is small.

关键词： nuclear shell model geometry property linear correlation randomize

EXAFS Studies on Local atomic Structure in the Amorphous Mg_(65)Cu_(2.)Gd_(10) Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2011年第1期26卷 98-101页

作者：李国强 Business Development department China Perfect Machinery Industry Corp. Ltd

Local atomic structures of an amorphous Mg65Cu2.Gd10 alloy and the structural changes by thermal annealing have been studied by extended X-ray absorption fine structure （EXAFS）. The correlation between structural changes and mechanical properties for the Mg65Cu2.Gd10 alloy has also been discussed. Results showed that Cu atoms around Gd in Mg65Cu2.Gd10 lost rapidly during annealing , resulting in the segregation of Cu atoms. The coordination number NGd-Mg of Mg65Cu2.Gd10 annealed at 373 K first diminished and then augmented with the increase of annealing time. The formation of polyhedral short-range order unit with coordination number of nearly 12.around Gd atoms is in favor of the improvement of mechanical properties. The chemical short-range order, not topological short-range order in the amorphous Mg65Cu2.Gd10 alloy had obvious changes during annealing.

关键词： magnesium alloy amorphous alloy short-range EXAFS mechanical properties annealing

The study of energy bands in nucleus ^(102.Zr

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2010年第1期53卷 106-110页

作者： DONG GuoXiang 1,2., YU ShaoYing 1,2.3 , LIU YanXin 1 , SHEN CaiWan 1,2.4 & DONG YongSheng 1,2.5I School of Science, Huzhou Teachers College, Huzhou 313000, China 2.School of Science and Information Engineering, Zhejiang Normal University, Jinhua 32.000, China 3 institute of Theoretical physics, Chinese Academy of Sciences, {2. 100080, China 4 Center of Theoretical nuclear physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, China 5 department of physics, Jining Teachers College, Jining 012.00, China 1. School of Science Huzhou Teachers College Huzhou 313000 China2. School of Science and Information Engineering Zhejiang Normal University Jinhua 321000 China3. Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100080 China4. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China5. Department of Physics Jining Teachers College Jining 012000 China

Theoretical calculations of the energy bands in nucleus 102.Zr are carried out by taking the projected shell model approach, which has reproduced the experimental data. In addition, by analyzing band-head energies, corresponding configurations of yrast band, quasi-particle rotational bands and side bands, we have worked out the microscopic formation mechanism of axially symmetric deformation bands: The low-excitation deformation bands are attributed to the high-j intruder states 1g 7/2.and 1h 11/2.in the N=4, 5 shells; the quasi-particles in the orbit v5/2.[532., v3/2.[411] and v3/2.[413] in particular play an important role in the deformation of 102.Zr.

关键词： projected shell model yrast band quasi-particle rotational band side band

Study of proton resonances in ^(18)Ne via resonant elastic scattering of ^(17)F+p and its astrophysical implication

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 32-36页

作者： HE JianJun1, HU Jun1,2. XU ShiWei1, CHEN ZhiQiang1, ZHANG XueYing1, WANG JianSong1, YU XiangQing1, ZHANG LiYong1,2. LI Long1,2. YANG YanYun1,2. MA Peng1,2. ZHANG XueHeng1, HU ZhengGuo1, GUO ZhongYan1, XU Xing1,2. YUAN XiaoHua1, LU Wan1,2. YU YuHong1, ZANG YongDong1,2. TANG ShuWen1,2. YE RuiPing1,2. CHEN JinDa1,2. JIN ShiLun1,2. DU ChengMing1,2. WANG ShiTao1,2. MA JunBing1,2. LIU LongXiang1,2. BAI Zhen1,2. LEI XiangGuo1, SUN ZhiYu1, ZHANG YuHu1, ZHOU XiaoHong1, XU HuShan1, SU Jun3, LI ErTao3, WANG HongWei4, TIAN WenDong4 & LI XiangQing5 1 institute of Modern physics (IMP), Chinese Academy of Sciences, Lanzhou 730000, China 2.Graduate University of Chinese Academy of Sciences, {2. 100049, China 3 China institute of atomic energy (CIAE), {2. 102.13. China 4 Shanghai institute of Applied physics (SINAP), Chinese Academy of Sciences, Shanghai 2.1800, China 5 School of physics and State Key Laboratory of nuclear physics and Technology, Peking University, {2. 100871, China 1. institute of Modern physics (IMP) Chinese Academy of Sciences Lanzhou 730000 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. China Institute of Atomic Energy (CIAE) Beijing 102413 China4. Shanghai Institute of Applied Physics (SINAP) Chinese Academy of Sciences Shanghai 201800 China5. School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China

The proton resonant properties in 18Ne, which determine the reaction rate of the key stellar 14O(α,p)17F reaction, have been studied by using a technique of proton resonant elastic scattering of 17F+p. A 4.2. MeV/nucleon 17F radioactive ion (RI) beam was produced via a projectile-fragmentation reaction, and separated by a Radioactive Ion Beam Line in Lanzhou (RIBLL). By bombarding a thick (CH2.n target, the energy spectra of the recoiled protons were measured by two ΔE-E silicon telescopes at the center-of-mass scattering angles of θc.m.≈175°±5°, θc.m.≈152.±8°, respectively. Several proton resonances in 18Ne were ob served clearly. A further R-matrix analysis of the experimental data is under way to determine the resonant parameters. The present work reports the preliminary results briefly.

关键词： resonant reaction reaction rate explosive burning accreting binary systems