Mingshi SONG
,
Wen ZHOU
,
Guixian HU
,
Lijiang HU
材料科学技术（英文）
A double-network model is established, which consists of the segments, E and A-constituent chains, the polymeric chains entangled with other ones by multi-entanglement and polymeric chains connected to a great number of destructible particles by multi-adsorption, based on which the E and A-constituent chains can be recreated and released dynamically. The distribution function of the end-to-end vector, the statistical distribution function of conformation for two kinds of chains in the multi-entanglement and multi-adsorption states and their number of polymeric chains are calculated by the combination of statistical mechanics and kinetics. Then the viscoelastic free energies of deformation for two kinds of the networks and suspensions are calculated by Boltzmann's statistical theory. Also, elastic modulus and memory function for two kinds of the network and suspensions are derived. Consequently, a new molecular theory of the non-linear viscoelasticity for polymeric suspensions is proposed, and the constitutive equation and material function with yielding and thinning for the polymeric suspensions in different flow fields are derived from this theory.
关键词:
Acta Physico-Chimica Sinica
In this paper, the quantum energy levels and the level splitting of the first and the second exicited states generated by the stretching vibration of CH and CD bonds in normal benzene C(6)H(6) (vapour and liquid) and deuterated benzene C(6)D(6) (vapour and liquid) have been studied in detail by new non-linear quantum mechanical theory in weak disperse limit. The distribution of energy levels of benzene molecules has been also obtained, and is consistent with experimental data.
关键词:
Non linear quantum mec hanical equation;Quantization;Vibration;Benzene;Quantum energy levels
Y.J. Li
,
J.S. Pan
,
M.J. Hu
,
D. Tian and W.M. Zhang Open Laboratory of the Educational Ministry for High Temperature Materials & Tests
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China
金属学报(英文版)
When FEM is utilized to simulate the quenching process of the workpiece and realize the coupled calculation of the temperature field and phase transformation, due to the effect of the complex shape, non-linear physical parameters and the latent heat during phase transformation, the element selection should be done cautiously so that end results can meet the actual situations. In this paper through comparing the different type and density of elements, the eight-node, hexahedral, isoparametric element is found to be a good choice. Using this kind of element can not only meets the need of calculating accuracy, but also cut down the calculating magnitude and takes full advantage of the hardware source. In addition, the effect of distorted elements on the calculation result has also been discussed in this paper.
关键词:
FEM
,
null
,
null
Mingshi SONG
,
Chen ZHANG
,
Guixian HU
材料科学技术（英文）
Based on the molecular theory of non-linear viscoelasticity with constrained entanglements in polymer melts, the material functions in simple shear flow were formulated, the theoretical relations between. eta((gamma) over dot), psi (10)((gamma) over dot) and shear rate ((gamma) over dot), and topologically constrained dimension number n ' and a were derived. Linear viscoelastic parameters (eta (0) and G(N)(0)) and topologically constrained dimension number (n ' a and <()over bar>) as a function of the primary molecular weight (M-n), molecular weight between entanglements (M-C) and the entanglement sites sequence distribution in polymer chain were determined. A new method for determination of viscoelastic parameters (eta (0), psi (10), G(N)(0) and J(e)(0)), topologically constrained dimension number (n ', a and v) and molecular weight (M-n, M-c and M-e) from the shear flow measurements was proposed. It was used to determine those parameters and structures of HDPE, making a good agreement between these values and those obtained by other methods. The agreement affords a quantitative verification for the molecular theory of nonlinear viscoelasticity with constrained entanglement in polymer melts.
关键词:
Chinese Physics Letters
A generally exact theory for predicting the effective behavior of coupled linear-response for inhomogeneous media is developed. The theory can not only give the general results of the effective principal and coupled moduli for the coupled multifield problems, but also provide the interrelationships between these effective moduli. It can be directly employed to describe the coupled two-held or three-held response of any inhomogeneous media.
关键词:
Journal of Physics D-Applied Physics
The dynamic aspects of linear elastic fracture mechanics applied to dielectric breakdown are studied. In the same direction as the fracture mechanics analogue for dielectric breakdown described previously by some researchers, this paper develops the intrinsic, rate-dependent bond breakdown micromechanism to account for the dynamic process of dielectric breakdown. The formulae of conducting microcrack growth rate and lifetime prediction are derived and applied to the experimental data of SiO2 films.
关键词:
sio2-films;oxides
