检索结果-南通市图书馆

THE COUNTER-JET FORMATION IN AN AIR BUBBLE INDUCED BY THE IMPACT OF SHOCK WAVES

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2011年第5期23卷 562-569页

作者： BAI Li-xin XU Wei-lin LI Chao GAO Yan-dong Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China State key laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China School of Electronic and Information Engineering Liaoning Technical University Huludao 125105 China

The interaction of an air bubble （isolated in water or attached to a boundary） with shock waves induced by electric sparks is investigated by high-speed photography. The interaction is closely related to the counter-jet induced by the impact of shock waves. The formation of a counter-jet in an air bubble is related to the liquid jet formed in the same air bubble, but the mechanism is different with that of the counter-jet formation in a collapsing cavitation bubble. The formation of a counter-jet in an air bubble is related to discharge energy, air bubble size and radius of shock wave. With a given energy of the spark discharge, the formation of a counter-jet in an air bubble is related to δ / ε （the ratio of the dimensionless bubble-bubble distance to the dimensionless air bubble radius）. The counter-jet will only be produced when δ / ε is in the range of 1.2-2.2. The counter-jet in an air bubble is of an important nuclei-generating mechanism.

关键词： cavitation bubble shock wave counter-jet high-speed photography

Multiparty quantum secret sharing of classical and quantum messages

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第1期17卷 26-31页

作者： CHEN Pan, DENG Fuguo and LONG Guilu ( key laboratory for Quantum Information and Measurements, and Department of Physics, Tsinghua University, beijing 100084, china key laboratory of Beam Technology and Material Modification, MOE, Institute of Low energy Nuclear Physics, and Department of Material Science and Engineering, beijing Normal University, beijing 100875, china beijing Radiation Center, beijing 100875, china key laboratory for Atomic and Molecular Nano-sciences, Tsinghua University, beijing 100084, china) [a]key laboratory for Quantum Information and Measurements and Department of Physics Tsinghua University Beijing China [b]key laboratory of Beam Technology and Material Modification MOE Institute of Low Energy Nuclear Physics and Department of Material Science and Engineering Beijing Normal University Beijing China [c]beijing Radiation Center Beijing China [d]key laboratory for Atomic and Molecular Nano-sciences Tsinghua University Beijing China

A scheme for multiparty quantum secret sharing of classical and quantum messages is proposed by using entanglement swapping. This scheme can distribute not only the classical information but also the quantum informati... 详细信息

关键词： quantum secret sharing classical message quantum message EPR pair.

New evidence for lack of CMB power on large scales

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) 2010年第3期53卷 567-570页

作者： LIU Hao1 & LI TiPei1,2,3 1 key laboratory of Particle Astrophysics, Institute of High energy Physics, chinese academy of sciences, beijing 100049, china 2 Department of Physics & Center for Astrophysics, Tsinghua University, beijing 100084, china 3 Department of Engineering Physics & Center for Astrophysics, Tsinghua University, beijing 100084, china 1. key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China2. Department of Physics & Center for Astrophysics Tsinghua University Beijing 100084 China3. Department of Engineering Physics & Center for Astrophysics Tsinghua University Beijing 100084 China

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2001年第4期19卷 399-405页

作者： Zhen-hua Yuan De-yan Shen Ren-yuan Qian Polymer Physics laboratory Center for Molecular Science, Institute of Chemistry chinese academy of sciences, beijing 100080 china chinese Acad Sci Inst Chem Ctr Mol Sci Polymer Phys Lab Beijing 100080 Peoples R China

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

Design of a new dynamical core for global atmospheric models based on some efficient numerical methods

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2004年第z1期47卷 4-21页

作者： WANG Bin, WAN Hui, Jl Zhongzhen, ZHANG Xin, YU Rucong, YU Yongqiang & LIU HongtaoState key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china Department of Computational Mathematics, academy of Mathematics and System sciences, Peking University, beijing 100871, china chinese Acad Sci Inst Atmospher Phys State Key Lab Numer Modeling Atmospher Sci & Geop Beijing 100029 Peoples R China Peking Univ Acad Math & Syst Sci Dept Computat Math Beijing 100871 Peoples R China

A careful study on the integral properties of the primitive hydrostatic balance equations for baroclinic atmosphere is carried out, and a new scheme todesign the global adiabatic model of atmospheric dynamics ispresented. This scheme includes a method of weighted equal-areamesh and a fully discrete finite difference method with quadraticand linear conservations for solving the primitive equationsystem. Using this scheme, we established a new dynamical corewith adjustable high resolution acceptable to the availablecomputer capability, which can be very stable without anyfiltering and smoothing. Especially, some important integralproperties are kept unchanged, such as the anti-symmetries of thehorizontal advection operators and the vertical convectionoperator, the mass conservation, the effective energy conservationunder the standard stratification approximation, and so on. Somenumerical tests on the new dynamical core, respectively regardingits global conservations and its integrated performances inclimatic modeling, incorporated with the physical packagesfrom the Community Atmospheric Model Version 2 (CAM2) of NationalCenter for Atmospheric Research (NCAR), are included.

关键词： dynamical core, equal-area mesh, anti-symmetry, effective energy conservation.

Observation constraints of the hard X-ray modulation telescope HXMT

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S1期53卷 31-35页

作者： LU Yu1,2,ZHANG WenZhao3,QU JinLu1,SONG LiMing1,GAO Jian3,ZHANG HongMei4 & OU Ge4 1 key laboratory of Particle Astrophysics,Institute of High energy Physics,chinese academy of sciences,beijing 100049,china 2 Graduate University of chinese academy of sciences,beijing 100049,china 3 Department of Astronomy,beijing Normal University,beijing 100875,china 4 Computing Center,Institute of High energy Physics,chinese academy of sciences,beijing 100049,china 1. key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China 2. Graduate University of chinese academy of sciences Beijing 100049 China 3. Department of Astronomy Beijing Normal University Beijing 100875 China 4. Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

The hard X-ray modulation telescope HXMT is a low orbit X-ray space telescope whose main science goals are to accomplish a hard X-ray all sky survey and to study timing and spectral characteristics of X-ray *** has three kinds of science instruments:the high energy X-ray detector(HE),the medium energy X-ray detector(ME) and the low energy X-ray detector(LE).The observation schedule of HXMT is a key to achieving the science goal of HXMT,and the analysis of the observation constraints is one of the first tasks in making the observation *** paper analyzes how the observation constraints influence the sky visibility and the visible time distribution of X-ray sources and discusses the schedule strategy with regard to the observation constraints.

关键词： HXMT observation constraints sky visibility

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

在线全文

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 2First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, china 3State key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, china 4Graduate University of chinese academy of sciences, beijing 100049, china 1. National Marine Environmental Forecasting Center Beijing 100081 China2. First Institute of Oceanography State Oceanic Administration Qingdao 266061 China3. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 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

Bifurcation timescales in power spectra of black hole binaries and ultraluminous X-ray sources

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S1期53卷 177-182页

作者： WANG TaiShan1 & LI TiPei1,2 1 Department of Physics & Center for Astrophysics,Tsinghua University,beijing 100084,china 2 key laboratory of Particle Astrophysics,Institute of High energy Physics,chinese academy of sciences,beijing 100049,china Tsinghua Univ Dept Phys Beijing 100084 Peoples R China Tsinghua Univ Ctr Astrophys Beijing 100084 Peoples R China chinese Acad Sci Inst High Energy Phys Key Lab Particle Astrophys Beijing 100049 Peoples R China

For black hole binaries(BHBs) and active galactic nuclei(AGNs),bifurcation timescales(BTs) Δtb exist,below which time-domain power is significantly higher than the corresponding Fourier ***-periodic oscillations(QPOs) are removed from the Fourier spectra of BHBs.A relationship between BT,black hole mass and bolometric luminosity is *** anti-correlation between BT and luminosity of Cyg X-1 is *** removing the QPOs,BTs are also obtained for two ultraluminous X-ray sources(ULXs),M82 X-1 and NGC5408 *** results support that they harbor intermediate mass black holes(IMBHs).

关键词： black hole binary ultraluminous X-ray source power spectral density data analysis

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 310027,china 1 Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, china 2Institute 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 Physics 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/Ser202 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 24 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