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Electro-mechanical response of functionally graded beams with imperfectly integrated surface piezoelectric layers

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Science China(Physics,Mechanics & astronomy) 2006年第5期49卷 513-525页

作者： YAN Wei1 & CHEN Weiqiu1,2 1. department of Civil Engineering, Zhejiang university, Hangzhou 310027, China 2. state Key Lab of CAD & CG, Zhejiang university, Hangzhou 310027, China 1. department of Civil Engineering Zhejiang University Hangzhou 310027 China 2. state Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

The time-dependent behavior of a simply-supported functionally graded beam bonded with piezoelectric sensors and actuators is studied using the state-space method. The creep behavior of bonding adhesives between piezoelectric layers and beam is characterized by a Kelvin-Voigt viscoelastic model, which is practical in a high temperature circumstance. Both the host elastic functionally graded beam and the piezoelectric layers are orthotropic and in a state of plane stress, with the former being inhomogeneous along the thickness direction. A laminate model is employed to approximate the host beam. Moreover, the coupling effect between the elastic deformation and electric field in piezoelectric layers is considered. Results indicate that the viscoelastic property of interfacial adhesives has a significant effect on the function of bonded actuators and sensors with time elapsing.

关键词： functionally graded beam piezoelectric layers Kelvin-Voigt model state-space method

How Fast Could a Proto-pulsar Rotate?

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Chinese Journal of astronomy and Astrophysics 2002年第6期2卷 533-538页

作者： Ren-Xin Xu, Hong-Guang Wang and Guo-Jun Qiaodepartment of astronomy, School of Physics, Peking university, Beijing 100871 department of astronomy School of Physics Peking University Beijing 100871

According to two estimated relations between the initial period and the dynamo-generated magnetic dipole field of pulsars, we calculate the statistical distributions of pulsar initial periods. It is found that proto-pulsars are very likely to have rotation periods between 20 ms and 30 ms, and that most of the pulsars rotate initially at a period < 60 ms. Our result supports the asymmetric neutrino emission model for pulsar kick.

关键词： pulsars neutron stars magnetic fields

An efficient quantum secret sharing protocol with orthogonal product states

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Science China(Physics,Mechanics & astronomy) 2007年第3期50卷 331-338页

作者： YANG YuGuang1,2, WEN QiaoYan3 & ZHU FuChen4.1 School of Computer, Beijing university of Technology, Beijing 100022, China 2 state Key Laboratory of Information Security, Graduate university of Chinese Academy of Sciences, Beijing 100022, China 3 School of Science, Beijing university of Posts and Telecommunications, Beijing 100876, China 4.National Key Laboratory for Modern Communications, Chengdu 61004., China 1. School of Computer Beijing University of Technology Beijing 100022 China 2. state Key Laboratory of Information Security Graduate University of Chinese Academy of Sciences Beijing 100022 China 3. School of Science Beijing University of Posts and Telecommunications Beijing 100876 China 4. National Key Laboratory for Modern Communications Chengdu 610041 China

An efficient quantum secret sharing protocol with orthogonal product states in the 33 Hilbert space is presented. The particles in the orthogonal product states form two particle sequences. One sequence is sent to Bob and the other is sent to Charlie after rearranging the particle orders. With the help of Alice, Bob and Charlie make the corresponding local measurement to obtain the information of the or- thogonal product states prepared. This protocol has many distinct features such as great capacity and high efficiency.

关键词： quantum secret sharing orthogonal product state orthogonal measurement

Pairwise entanglement and local polarization of Heisenberg model

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Science China(Physics,Mechanics & astronomy) 2008年第10期51卷 1515-1522页

作者： XI XiaoQiang1,2, ZHANG Tao3, YUE RuiHong3,4.& LIU WuMing2 1 department of Applied Mathematics and Physics, Xi’an Institute of Post and Telecommunications, Xi’an 710061, China 2 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China 3 Institute of Modern Physics, Northwest university, Xi’an 710069, China 4.department of Physics, Ningbo university, Ningbo 315211, China department of Applied Mathematics and Physics Xi’an Institute of Post and Telecommunications Xi’an 710061 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China Institute of Modern Physics Northwest University Xi’an 710069 China department of Physics Ningbo University Ningbo 315211 China

The characteristics of pairwise entanglement and local polarization (LP) are dis-cussed by studying the ground state (states) of the Heisenberg XX model. The re-sults show that: the ground state (states) is (are) composed of the micro states with the minimal polarization (0 for even qubit and 1/2 for odd qubit); LP and the prob-ability of the micro state have an intimate relation, i.e. the stronger the LP, the smaller the probability, and the same LP corresponds to the same probability; the pairwise entanglement of the ground state is the biggest in all eigenvectors. It is found that the pairwise entanglement is decreased by the state degeneracy and the system size. The concurrence approaches a fixed value of about 0.34.2 (for odd-qubit chain) or 0.34.1 (for even-qubit chain) if the qubit number is large enough.

关键词： Heisenberg XX model local polarization pairwise entanglement

A first-principles study of dihydroazulene as a possible optical molecular switch

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Science China(Physics,Mechanics & astronomy) 2011年第3期Mechanics & Astronomy) .卷 437-441页

作者： XIA CaiJuan1, LIU DeSheng2,3 & LIU HanChen1 1 School of Science, Xi’an Polytechnic university, Xi’an 71004., China 2 School of Physics, state Key Laboratory of Crystal Materials, Shandong university, Jinan 250100, China 3 department of Physics, Jining university, Qufu 273155, China 1. School of Science Xi’an Polytechnic University Xi’an 710048 China2. School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China3. Department of Physics Jining University Qufu 273155 China

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.

关键词： molecular switch nonequilibrium Green’s function electronic transport density functional theory

The refined theory of deep rectangular beams for symmetrical deformation

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Science China(Physics,Mechanics & astronomy) 2009年第6期52卷 919-925页

作者： GAO Yang1 & WANG MinZhong2 1 College of Science, China Agricultural university, Beijing 100083, China 2 state Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Aerospace Engineering, Peking university, Beijing 100871, China College of Science China Agricultural University Beijing 100083 China state Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Aerospace Engineering Peking University Beijing 100871 China

Based on elasticity theory, various one-dimensional equations for symmetrical deformation have been deduced systematically and directly from the two-dimensional theory of deep rectangular beams by using the Papkovich-Neuber solution and the Lur'e method without ad hoc assumptions, and they construct the refined theory of beams for symmetrical deformation. It is shown that the displacements and stresses of the beam can be represented by the transverse normal strain and displacement of the mid-plane. In the case of homogeneous boundary conditions, the exact solutions for the beam are derived, and the exact equations consist of two governing differential equations: the second-order equation and the transcendental equation. In the case of non-homogeneous boundary conditions, the approximate governing differential equations and solutions for the beam under normal loadings only and shear loadings only are derived directly from the refined beam theory, respectively, and the correctness of the stress assumptions in classic extension or compression problems is revised. Meanwhile, as an example, explicit expressions of analytical solutions are obtained for beams subjected to an exponentially distributed load along the length of beams.

关键词： deep rectangular beams the refined theory symmetrical deformation the Papkovich-Neuber solution the Lur’e method

From Femtochemistry to 4. Microscopy

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Science China(Physics,Mechanics & astronomy) 2010年第6期53卷 977-986页

作者： ZHONG Dongping departments of Physics,Chemistry,and Biochemistry,Programs of Biophysics,Chemical Physics,and Biochemistry,191 West Woodruff Avenue,The Ohio state university,Columbus,OH 4.210,usa 1. departments of Physics Chemistry and Biochemistry Programs of Biophysics Chemical Physics and Biochemistry The Ohio State University 191 West Woodruff Avenue Columbus OH 43210 USA

To celebrate the 10th anniversary of the Nobel Prize for Femtochemistry,the field is overviewed with several classic examples and the new extension to Femtobiology. The revolutionary breakthrough in 4. electron microscopy is briefly introduced here and a new age to structural dynamics is rising on the horizon,an exciting time and a great opportunity for China and for the world.

关键词： femtosecond dynamics molecular coherence structural dynamics and complexity

Nilsson mean-field plus extended pairing model for Well-Deformed Nuclei in Rare-earth Region

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Nilsson mean-field plus extended pairing model for Well-Defo...

From a bound excited state to a singly excited resonanceatoms in plasma environment

第十三届全国核结构研讨会暨第九次全国“核结构与量子力学”专题讨论会

作者： Xin Guan~(1)) Feng Pan~(1,2)) 1(department of Physics,Liaoning Normal university,Dalian,116029,P.R.China) 2(department of Physics and astronomy,Louisiana {4. university,Baton Rouge,LA 70803,usa)

mean-field plus extended pairing force with multi-pair interaction for the description of well-deformed nuclei is ***-energies of the model and the corresponding wave functions can easily be evaluated by using a numerical algorithm based on the exact *** application of the model,binding energies,pairing excitation energies,even-odd mass differences of Er,Yb,Hf isotopes are calculated in proton pair excitation frozen *** with the corresponding experimental data,the BCS model and the nearest-orbit pairing model,the results show that the extended pairing model is suitable to be used to describe well-deformed nuclei in rare-earth region and it is more exactly than the other two models.

关键词： Nilsson mean-field extended pairing interaction binding energy pairing excitation odd-even mass difference

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From a bound excited state to a singly excited resonanceatom...