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181.
Y.B. DongOn leave from Institute of High Energy Physics Academia Sinica Beijing P. R. China--> A. Faessler K. Shimizu 《The European Physical Journal A - Hadrons and Nuclei》1999,6(2):203-210
Electromagnetic form factors of protons and neutrons are investigated based on a relativistic quark model with the inclusion
of a pion cloud. Pseudo-scalar π-quark interaction is employed to study the coupling between the nucleon and the π. The results
show the important role of the pion cloud for the neutron charge form factor. Moreover, our numerical analysis indicates a
difference between the relativistic and the nonrelativistic treatments.
Received: 10 March 1999 / Revised version: 14 June 1999 相似文献
182.
A. Banerjee M.K. Harbola 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):201-206
Employing a near exact Hylleraas wavefunction we calculate various third-order nonlinear optical properties for the helium
atom within the time-dependent Kohn-Sham theory. In our calculations we employ the adiabatic local-density approximation (ALDA)
for the exchange and correlation kernels fxc and gxc, and compare the numbers obtained by us with the available accurate theoretical as well as experimental results. Our results
demonstrate the accuracy of ALDA for the calculation of nonlinear optical properties of many electron systems.
Received: 22 June 1998 / Accepted: 15 October 1998 相似文献
183.
Xiao-bo Wan Yun Lu Xiao-rong Liu Liang Zhou Shi Jin Gi Xue Department of Polymer Science Engineering the State Key Laboratory of Coordination Chemistry Nanjing University Nanjing China 《高分子科学》1999,(2):99-111
The complexation of thiophene with a Lewis acid with moderate acidity as a solvent, such as BF_3-ethyl ether (BFEE) remarkedly lowered the electrochemical polymerization potential. The positively chargedmetal surface of electrode in the process of electrochemical deposition enhanced the coordination interactionbetween π-electrons of thiophene unit and the metal, which makes thiophene rings lie parallel to the surfaceof electrode, resulting in a highly ordered polymeric structure. Because of the large intra-chain transferintegrals, the transport of charge is believed to be principally along the conjugated chains, which is muchgreater than the inter-chain hopping. The specific electrical resistance across the polythiophene film thicknessis more than 10~4 times than that along the surface plane of the film. In this paper we review the recentdevelopment of polymerization technique by low potential electrochemical method performed in our lab andseveral electrical devices in which the compact polythiophene films, such as anionic and cationic sieves, andlaminate film junction of undoped polythiophene derivatives were used. 相似文献
184.
A new method for the evaluation of one- and two-centre magnetic and electric multipole integrals for Slater-type functions
is presented. The method is strictly analytical in that no approximations of any kind are involved. Two simple functions,
ℐ1
aug and ℐ2
aug, are introduced, which employ only functions that are well known in electronic structure theory. With the use of augmentation
exponents these functions apply to multipole integrals as well as other one-electron integrals, such as nuclear attraction
integrals. The proposed method includes the analytic determination of derivatives of the integrals with respect to atomic
displacements. Some illustrative test calculations are presented and compared to results from the literature.
Received: 20 April 1998 / Accepted: 13 October 1998 / Published online: 1 February 1999 相似文献
185.
电场对量子阱中自由载流子光辐射线宽的影响 总被引:7,自引:0,他引:7
付方正 《光谱学与光谱分析》1999,(6)
本文对固体中在较大空间范围运动的粒子采用轨道、动量及波包来描述。根据量子力学测不准关系, 粒子的能量测不准公式被导出。公式表明, 电场强烈地散射载流子, 使载流子所处能级大为展宽。应用该公式到P-I-N结构的GaAs/GaAlAs 多量子阱中, 理论计算的光辐射线宽与光致荧光实验测得的线宽吻合。 相似文献
186.
Gerhard Schmid 《Journal of membrane science》1998,150(2):151-157
In capillary systems with narrow pores the Helmholtz electrochemical double layer located at the pore wall extends over the entire cross section of the pores. It loses its character as the “charge on the wall”. It will be shown that not only the electrokinetic phenomena but also the electrical conductivity and the dialysis potential of membranes with narrow pores can be understood from the same point of view, namely: the electrolyte solution in the pores of a membrane with narrow pores is considered to be an approximately homogeneous solution in contact with immobilised charges located at the pore wall. In this case the electrochemical equations contain the fixed ion concentration as a parameter instead of the ζ potential. This makes it possible to describe quantitatively to a good approximation data on the electroosmosis, the electrical conductivity, the streaming potential and the dialysis potential taken from the literature, as well as results of our own measurements, by using a single membrane constant. 相似文献
187.
E. Benichou A.R. Allouche R. Antoine M. Aubert-Frecon M. Bourgoin M. Broyer Ph. Dugourd G. Hadinger D. Rayane 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(2):233-242
A non perturbative approach is used to solve the problem of a rigid linear molecule with both a permanent dipole moment and
a static dipole polarizability, in a static electric field. Eigenenergies are obtained and compared to perturbative low field
and high field approximations. Analytical expressions for the orientation parameters and for the gradient of the energy are
given. This non perturbative approach is applied to the simulation of beam deviation experiments in strong electric field.
Results of simulations are given for inhomogeneous alkali dimers. For LiNa, the simulations are compared to experimental data.
For LiK, deviation profiles have been simulated in order to prepare future experiments on this molecule.
Received 21 July 1999 and Received in final form 22 September 1999 相似文献
188.
Determination of titanium NMR parameters of ATiO3 compounds: correlations with structural distortion
Solid state 47,49Ti NMR spectra have been obtained for a number of perovskite and ilmenite ATiO3 compounds. The 49Ti quadrupole coupling constant varies from 2.75 MHz (CaTiO3) to 15.5 MHz (MgTiO3) and the electric field gradient at the titanium site was found to correlate well with the shear strain, independent of structure. The chemical shift in the perovskite structures varies by 160 ppm and correlates well with the mean Ti–O distance. The 25Mg and 113Cd NMR parameters are also reported for the relevant compounds. 相似文献
189.
190.
APOLLONOV V V 《中国光学》2011,4(1):9-20
对低频共振情况下激光引擎的基本特性与其理论预测值做了比较,并研究了实现这些技术的重要步骤,认为基于不同学科与工业组织之间的合作,不久的将来会实现利用累计势能来驱动微型汽车。 相似文献