检索结果-南通市图书馆

casimir force at a Finite Cut-Off

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第12期50卷 1317-1322页

作者： XIONG Ai-Min CHEN Xiao-Song Institute of Theoretical Physics Chinese Academy of Sciences P.O. Box 2735 Beijing 100080 China

We calculate the casimir force at a finite cut-off A by summing the forces induced by the all fluctuation modes. We show that the casimir force is independent of the cut-off function in the limit L∧ → ∞. There is a correction in the order of （L∧）^-2, when L∧ is finite and large. This correction becomes remarkable when L is comparable with the microscopic length scale ∧^-1. It has been demonstrated that the casimir force at a finite cut-off should be defined by summing forces of all fluctuation modes, instead of the derivative of casimir energy with respect to L where an additional derivative of the cut-off function has been introduced.

关键词： vacuum fluctuation casimir force finite cut-off

casimir force in a One-Dimensional Cavity with Quasimode

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2014年第5期61卷 641-644页

作者：潘淑梅田甜杨慧郑泰玉张雪邵晓强郑丽 School of Physics Northeast Normal University Key laboratory of Frontiers in Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Information Science and Engineering College Dalian Polytechnic University

We calculate the casimir force between a perfect reflective wall and a semitransparent wall in the laser cavity. Using the Fox–Li quasimode theory to describe the electromagnetic field in the laser cavity, the vacuum energy and the casimir force are calculated. We compare our results to the force in the ideal situation and find it smaller in the dissipative cavity. We also find that the casimir force decreases with the increase of the wall-wall distance and the decay rate of the quasimodes in the laser cavity.

关键词： casimir force Fox-Li quasimode

Isotope effect on the casimir force

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2023年第10期66卷 131-137页

作者： Lanyi Xie Fuwei Yang Bai Song Department of Energy and Resources Engineering Peking UniversityBejing 100871China Center for Nano and Micro Mechanics Tsinghua UniversityBejing 100084China Department of Advanced Manufacturing and Robotics Peking UniversityBejing 100871China Beijing Innovation Center for Engineering Science and Advanced Technology Peking UniversityBeijing 100871China

Isotopic dependence of the casimir force is key to probing new physics and pushing novel technologies at the micro and nanoscale, but is largely unexplored. In 2002, an isotope effect of 10^(-4) was estimated for metals—orders of magnitude beyond the experimental resolution. Here, by employing the Lifshitz theory, we reveal a significant isotope effect of over 10^(-1) for polar dielectrics. This effect arises from the isotope-mass-induced line shift of the zone-center optical phonons and is insensitive to the linewidth. We perform numerical analyses on both the imaginary and real-frequency axes, and derive analytical formulas for predicting the isotope effect. The three-orders-of-magnitude difference between polar dielectrics and metals arises from the distinct isotopic dependence of the phonon and plasma frequencies. Our work opens up a new avenue for engineering forces at small scales and may also facilitate the quest for the fifth force of nature.

关键词： isotope effect casimir force polar dielectric phonon line shift plasma frequency

Corrections to the casimir force Due to Interactions of Plasmons and Electromagnetic Field

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai Jiaotong university(Science) 2005年第3期10卷 288-292页

作者：李铜忠 Dept. of Physics Shanghai Jiaotong Univ. Shanghai 200240 China

Considering the interaction between the electromagnetic field and matter field, a concise method is used to calculate the ground-state energy of the interacting system. With the assumption of squeezed-like state, a new vacuum state is obtained for the inte racting system. The energy of the new vacuum state is obviously lower than that of unperturbed vacu um state. Based on the new vacuum state, the correction to the casimir force is obtained. The r esult shows that the contribution of the interaction is a repulsive one and the casimir effect is attributed to both electromagnetic field and matter field. On the basis of the obtained results, th e recent experimental data can be explained reasonably.

关键词： casimir force electromagnetic field matter field

casimir force Correction Between Parallel Polysilicon Plates

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2002年第3期7卷 276-280页

作者：丁建宁孟永钢温诗铸 State Key Laboratory of Tribology Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084 China

Both the size of the components and the separation between them in some microelectromechanical systems (MEMS) are already in the sub-micrometer regime, where quantum mechanical effects such as the casimir effect will need to be considered. This paper theoretically analyzes the roughness, electrical conductivity, and temperature corrections due to the casimir force between two parallel polysilicon plates. The theoretical results show that the combined effects of roughness, conductivity and temperature cause a maximum relative error of the casimir force per unit area of 26.2% between parallel polysilicon plates separated by 1 μm. Therefore, the surface roughness and finite conductivity corrections should be taken into account when calculating precise casimir forces with separations on the order of 1 μm.

关键词： casimir force polysilicon microelectromechanical system (MEMS)

Anharmonic 1D actuator model including electrostatic and casimir forces with fractional damping perturbed by an external force

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2018年第3期34卷 528-541页

作者： Maryam Mansoori Kermani Maryam Dehestani Department of Chemistry Shahid Bahonar University of Kerman

We modeled a one-dimensional actuator including the casimir and electrostatic forces perturbed by an external force with fractional damping. The movable electrode was assumed to oscillate by an anharmonic elastic force originated from Murrell- Mottram or Lippincott potential. The nonlinear equations have been solved via the Adomian decomposition method. The behavior of the displacement of the electrode from equilibrium position, its velocity and acceleration were described versus time. Also, the changes of the displacement have been investigated according to the frequency of the external force and the voltage of the electrostatic force. The convergence of the Adomian method and the effect of the orders of expansion on the displacement versus time, frequency, and voltage were discussed. The pull-in parameter was obtained and compared with the other models in the literature. This parameter was described versus the equilibrium position and anharmonicity constant.

关键词： Murrell-Mottram potential Lippincott potential casimir force Fractional damping Pull-in parameter Adomian decomposition method

Pull-in instability analyses for NEMS actuators with quartic shape approximation

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2016年第3期37卷 303-314页

作者： Junsheng DUAN Zongxue LI Jinyuan LIU School of Sciences Shanghai Institute of Technology College of Computer and Information Inner Mongolia Medical University Department of Information Management Party School of the Inner Mongolia Committee of the Communist Party of China

The pull-in instability of a cantilever nano-actuator model incorporating the effects of the surface, the fringing field, and the casimir attraction force is investigated. A new quartic polynomial is proposed as the shape function of the beam during the deflection, satisfying all of the four boundary values. The Gaussian quadrature rule is used to treat the involved integrations, and the design parameters are preserved in the evaluated formulas. The analytic expressions are derived for the tip deflection and pull-in parameters of the cantilever beam. The micro-electromechanical system （MEMS） cantilever actuators and freestanding nano-actuators are considered as two special cases. It is proved that the proposed method is convenient for the analyses of the effects of the surface, the casimir force, and the fringing field on the pull-in parameters.

关键词： micro-electromechanical system (MEMS) nano-electromechanical system(NEMS) casimir force pull-in instability quartic shape function

Shape of Compact Toroidal Dimensions T_θ~d and casimir Effect on M^D×T_θ~d Spacetime

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2011年第1期55卷 101-110页

作者： V.K.Oikonomou Department of Theoretical Physics Aristotle University of Thessaloniki Technological Education Institute of Serres

We study the influence of the shape of compact a scalar field. We examine both the massive and the massless dimensions to the casimir energy and casimir force of scalar field. The total spacetime topology is M^D × Tθ2, where M^D） is the D-dimensional Minkowski spacetime and Tθ2 the twisted torus described by R1, R2, and 8. For the case R1 = R2 we found that the massive bulk scalar field casimir energy is singular for D=even and this singularity is R-dependent and remains even when the force is calculated. Also the massless casimir energy and force is regular only for D = 4 （!）. This is very interesting phenomenologically. We examine the energy and force as a function of 8. Also we address the stabilization problem of the compact space. We also briefly discuss some phenomenological implications.

关键词： casimir energy casimir force extra dimensions twisted torus shadowing effect zeta dimensions

Quantitative Structure-activity Relationship for Heterogeneous Phenol Compounds Using Zero Point Energy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2010年第9期29卷 1353-1361页

作者：金飙刘翠金俏 School of Environment & Biology Engineering Shenyang University of Chemical Technology School of Chemical Engineering Beijing Institute of Petrochemical Technology

The calculations of quantum mechanical descriptors of 79 heterogeneous phenol compounds were presented at the HF/6-31G＊ and B3LYP/6-31G＊ levels of *** structure-activity relationship（QSAR） models of the growth inhibition activity（pIGC50） of 79 heterogeneous phenols were established using some of the following calculated quantum mechanical descriptors：the zero point energy（ZPE）,the front-line orbital energy（EHOMO,ELUMO）,the differences between HOMO and LUMO energies（ΔE）,and the molecular dipole moment（μ）.The QSAR models obtained by employing multiple linear regression techniques are aimed at correlating the structures to their experimental *** most significant is a one-parameter linear equation with the correlation coefficient R2 values to be 0.855（HF） and 0.844（B3LYP）.The results display that the zero point energy as a special quantum-chemical descriptor in the QSAR equations indicates the existence of casimir force in the interaction between the molecules of compounds and biological receptor（cells）.The physical mechanism of structure-activity of the molecules at a deeper level would have a new understanding.

关键词： qsar zpe casimir force quantum-chemistry descriptor