A THEORETICAL APPROACH TO THERMAL PROPERTY OF ARRAY OF CYLINDERS EMBEDDED IN HOMOGENEOUS MATRIX

We investigate in this article the thermal coliductivity of array Of cylinders embedded in a homogeneous matrix. Using Green's function, we confirm that the method invented by Rayleigh can be generalized to deal with thermal property of these systems. A technique for calculating effective thermal conductivities of these systems is proposed. As an example, we consider a system with square symmetry, and a neat formula for effective thermal conductivity is derived. We show that the method also includes the proof of Keller theorem.

Theoretical and Experimental Investigation of Flexural Vibration Transfer Properties of High-Pressure Periodic Pipe

According to the theory of phononic crystals, the hydraulic pipeline is designed to be a periodic structure composed of steel pipes and hoses to suppress the vibration of the hydraulic system with band gaps. We present theoretical and experimental investigations into the flexural vibration transfer properties of a high-pressure periodic pipe with the force on the inner pipe wall by oii pressure taken into consideration. The results show that the vibration attenuation of periodic pipe decreases along with the elevation of working pressure for the hydraulic system, and the band gaps in low frequency ranges move towards high frequency ranges. The periodic pipe has good vibration attenuation performance in the frequency range below 1000 Hz and the vibration of the hydraulic system is effectively suppressed. A11 the results are validated by experiment. The experimental results show a good agreement with the numerical calculations, thus the flexural vibration transfer properties of the high- pressure periodic pipe can be precisely calculated by taking the fluid structure interaction between the pipe and oil into consideration. This study provides an effective way for the vibration control of the hydraulic system.

Theoretical Investigation of Influence of Mechanical Stress on Magnetic Properties of Ferromagnetic/Antiferromagnetic Bilayers Deposited on Flexible Substrates

Effect of mechanical stress on magnetic properties of an exchange-biased ferromagnetic/antiferromagnetic bilayer deposited on a flexible substrate is investigated. The hysteresis loops with different magnitudes and orientations of the stress can be classified into three types. The corresponding physical conditions for each type of the loop are deduced based on the principle of minimal energy. The equation of the critical stress is derived, which can judge whether the loops show hysteresis or not. Numerical calculations suggest that except for the magnitude of the mechanical stress, the relative orientation of the stress is also an important factor to tune the exchange bias effect.

Theoretical Study on the Spectroscopic Parameters and Transition Properties of MgH Radical Including Spin-orbit Coupling

An accurate theoretical study on the MgH radical is reported by adopting the high-level relativistic MRCI＋Q method with a quintuple-zeta quality basis set. The reliable potential energy curves of the five A-S states of MgH are derived. Then the associated spectroscopic parameters are determined and found to be in good accordance with the available experimental results. The permanent dipole moments （PDMs） and the spin-orbit （SO） matrix elements of A-S states are computed. The results show that the abrupt changes of PDMs and SO matrix elements are attributed to the variations of electronic configurations at the avoided crossing point. The SOC effect leads to the five A-S states split into ten Ω states and results in the double potential well of （2）1//2 state. Finally, the transition properties from the （2）1//2, （1）3//2 and （3）1//2 states to the ground state X2∑＋1//2 transitions are obtained, including the transition dipole moments, Franck-Condon factors and radiative lifetimes.

A THEORETICAL STUDY OF THE THERMODYNAMIC AND KINETIC PROPERTIES FOR THE REACTION OF FORMYL CYANIDE DECOMPOSITION

We compute the thermodynamic and the kinetic properties for the reaction: HCOCN→HCH+CO using the statistical theory and the transition-state theory.The equi- librium constants and the rate coefficients of this reaction are also reported here,and the half lives of formyl cyanide at different temperatures are first estimated in this work.

Effective electromechanical properties of cellular piezoelectret:A review

Due to the large quasi-piezoelectric d33 coefficient in the film thickness direction, cellular piezoelectret has emerged as a new kind of compliant electromechanical transducer materials. The macroscopic piezoelectric effect of cellular piezoelectret is closely related to the void microstructures as well as the material constants of host polymer. Complex void microstmctures are usually encountered in the optimum design of cellular piezoelectret polymer film with ad- vanced piezoelectric properties. Analysis of the effective electromechanical properties is generally needed. This article presents an overview of the recent progress on theoretical models and numerical simulation for the effective electromechanical properties of cellular piezoelectret. Emphasis is placed on our own works of cellular piezoelectret published in past several years.

Theoretical relationship between sound velocity and the physical properties of submarine sediment

Density and elastic modulus change ratios are introduced to describe the sound velocity of submarine sediment. The density change ratio is a composite parameter describing the sound velocity. It is expressed by three physical parameters： porosity, solid phase density and seawater density. The elastic modulus change ratio is also a composite parameter of sound velocity. It is expressed by three physical parameters, including porosity, solid phase modulus and seawater bulk modulus. The sound velocity formula can be developed into a Taylor polyno- mial formula of these two composite parameters. The change in the two composite parameters constitutes the sound velocity surface, which contains the complete information regarding ve- locity properties and sediment characteristics. The one-parameter velocity formula is a curve on the velocity surface. Each porosity-velocity empirical formula, which represents various sea locations and conditions, is transformed to a standard form. This result is the product of a reference velocity and a modulation function. Comparisons of the numerical calculation and measurements show that the derived modulation functions yield similar results. The difference between the velocity formula derived in this paper and the Wood velocity formula is due to the elastic modulus models.

Selection of Fixed Effects in High-dimensional Generalized Linear Mixed Models

The selection of fixed effects is studied in high-dimensional generalized linear mixed models(HDGLMMs)without parametric distributional assumptions except for some moment conditions.The iterative-proxy-based penalized quasi-likelihood method(IPPQL)is proposed to select the important fixed effects where an iterative proxy matrix of the covariance matrix of the random effects is constructed and the penalized quasi-likelihood is adapted.We establish the model selection consistency with oracle properties even for dimensionality of non-polynomial(NP)order of sample size.Simulation studies show that the proposed procedure works well.Besides,a real data is also analyzed.