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141.
Y.W. Duan L. Shi M. Feng X. Zhu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(2):191-197
The hyperspherical-coordinate approach is employed to a one-dimensional model of three ions in a Paul trap. It is shown that
the eigen wave functions have well-defined nodal structure indicating a near separability in the hyperspherical coordinates, then two approximate good quantum numbers
are introduced to classify the eigenstates. Three important classical periodic motions, including the breathing motion and
the (distorted-)symmetric or anti-symmetric stretching motion, are found to dominate the wave function distribution.
Received: 10 February 1999 / Received in final form: 25 March 1999 相似文献
142.
D.J Carp G.B Bartholomai A.M.R Pilosof 《Colloids and surfaces. B, Biointerfaces》1999,12(3-6):309-316
The aim of this work was to elucidate soy proteins–xanthan gum interactions at a molecular level by studying protein composition at the air–water interface of foams and in the solutions used to make them and to see if the different properties of heat denatured protein were reflected in the proportions in which they were present at the interface or in the ability to interact with xanthan. To this end SDS-PAGE and densitometry was employed. Initial protein concentration and xanthan influenced the composition of proteins in the solutions used to make the foams. The increase in NSP concentration of solutions (0.5–6 wt.%) in the absence of xanthan promoted the formation of aggregates of low molecular weight (160 kDa), the association of A an B polypeptides and a decrease in and ′ subunits. As DSP concentration of solutions increased, an increase in the proportion of aggregates of high molecular weight (above 200 kDa) and B-polypeptide was observed. On addition of xanthan (0.025 and 0.05%) to protein solutions (0.5 and 2%), the formation of aggregates of high molecular weight was favoured for both NSP and DSP. In the absence of xanthan, no preferential adsorption of soy polypeptides was observed at the air–water interface of NSP foams. However in DSP foams, there was a preferential adsorption of B-polypeptides. Xanthan present in NSP foams (0.5 or 2%), caused an increase in the proportion of aggregates of high molecular weight at the interface as compared with the composition of solutions used to make the foams. An increase in proportion of AB-polypeptides (for 0.5% NSP and 0.025% xanthan) and B-polypeptides together with polypeptides of molecular weight lower than 14 kDa (for 0.5% NSP and 0.05% xanthan) was also observed at the interface in NSP foams. On the contrary, the presence of xanthan in DSP foams caused a decrease in the proportion of aggregates of high molecular weight and a concomitant increase in B-polypeptide. The B-11S polypeptide predominated the interface of DSP foams probably for its hydrophobicity and basic characteristics. 相似文献
143.
Films of (Cd-Pb)S have been prepared using chemical deposition in aqueous alkaline bath and their subsequent condensation on substrates. Important achievements in terms of electrical response, optical absorption and photoconductivity (PC) excitation spectra, SEM, XRD and photoluminescence (PL) studies are presented and discussed. From the photocurrent curves, the ratio I PC (saturated photocurrent)/I DC (dark current) was observed to be of the order of 106 for the systems prepared with CdCl2, and to be 107 when doped with samarium nitrate. Values of trap depth E, lifetime and mobility are evaluated from the PC decay. Band gaps are determined from the two spectra. Diffraction lines in XRD studies are associated with CdS and PbS, and according to SEM studies, layered growth of the films takes place. PL of samarium-doped (Cd-Pb)S films shows an emission peak in the green-yellow region under 365-nm excitation. The PL brightness decreases with temperature. 相似文献
144.
K.-E. Thylwe 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(3):591-596
The analysis of bound radial Dirac states is shown to simplify for problems with an equal mixture of Lorentz vector and Lorentz scalar potentials, thus satisfying a so-called spin symmetry of the energy spectrum. Typical relativistic restrictions on potentials that are singular at the origin then disappear.
Such potentials may even be strongly singular at the origin like the well known Lennard-Jones potentials modelling many atom-atom
interactions, and they reduce to non-relativistic potentials of identical form. Bound state energies for potentials with equal
vector- and scalar couplings are compared with those of a pure vector coupling of the same radial (attractive screened and
unscreened Coulomb) shapes, and with non-relativistic results. 相似文献
145.
The Taylor dispersion technique has been used for measuring mutual diffusion coefficients of β-cyclodextrin sulfated sodium salt (NaSO3βCD) at temperatures (298.15 and 310.15) K and at finite concentrations. These studies have been complemented by density and viscosity measurements. From these experimental results, the hydrodynamic radius Rh, and its dependence on the viscosity, diffusion coefficient at infinitesimal concentration, D0, ion conductivity of NaSO3βCD and the thermodynamic factor, FT, have been estimated, permitting us to have a better understanding of the structure of the aqueous system containing NaSO3βCD. 相似文献
146.
利用临界点理论的极小化原理讨论一类非自治p-L ap lace系统d/(dt)(q(t)p-2q(t))-l(t)q(t)p-2q(t)+▽W(t,q(t))=0非平凡同宿轨道的存在性,其中,p>1,t∈R,q∈Rn,l:R→(0,+∞),W(t,q(t))=a(t)q(t)γ且a(t):R→R+是一非负连续函数,1<γ
相似文献
147.
We develop a new method of solving the Bethe-Salpeter (BS) equation in Minkowski space. It is based on projecting the BS equation
on the light-front (LF) plane and on the Nakanishi integral representation of the BS amplitude. This method is valid for any
kernel given by the irreducible Feynman graphs. For massless ladder exchange, our approach reproduces analytically the Wick-Cutkosky
equation. For massive ladder exchange, the numerical results coincide with the ones obtained by Wick rotation. 相似文献
148.
The periodic boundary value problem for a class of second order nonlinear integro-differential equations are disussed by using the monotone iterative technique. The open problem raised by Lakshmikantham in 1986 is solved. 相似文献
149.
Hans Ulrich Borgstedt Cezary Guminski 《Monatshefte für Chemie / Chemical Monthly》2000,131(9):917-930
Summary. Experimental solubility data for metals and non-metallic substances in liquid alkali metals have been collected from literature,
critically evaluated, and selected for recommendation. Sometimes results for a selected system at a selected temperature vary
over more than an order of magnitude. This is not uniquely connected with a poor precision of the measurements. Some impurities
may spectacularly modify the solubilities and, moreover, definition of a saturating solute phase is not always a simple task.
Based on supplementary experiments one may explain several phenomena which often accompany dissolution processes. These accompanying
processes are essentially the same as those frequently observed in solution chemistry.
Received February 3, 2000. Accepted (revised) May 8, 2000 相似文献
150.
莫嘉琪 《高校应用数学学报(A辑)》1996,(2):173-178
本文研究了具有非局部反应扩散方程的奇摄动问题。利用比较原理,讨论了相应问题解的存在唯一性及其渐近性态。 相似文献