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31.
D. B. Abraham 《Journal of statistical physics》1984,34(5-6):793-801
Some recent results in the application of statistical mechanics to surfaces are discussed. Only exactly soluable models are described. First, we consider phase separation below the critical temperature in uniaxial ferromagnets and their analogs. We then consider the determination of the equilibrium shape of a crystal having fixed volume, given the orientation-dependent surface tension, using the Wulff construction. 相似文献
32.
A modification of Armijo's step-size rule for negative curvature 总被引:10,自引:0,他引:10
Garth P. McCormick 《Mathematical Programming》1977,13(1):111-115
Armijo's step-size procedure for function minimization is modified to include second derivative information. Accumulation points using this procedure are shown to be stationary points with positive semi-definite Hessian matrices.This research was supported by the United States Army Research Office. 相似文献
33.
34.
A transitory etching regime after SiO2 dissolution and before bulk Si(1 1 1) etching in neutral NH4F solutions was monitored by in situ Brewster-angle reflectometry (BAR). An observed intermediate increase of the BAR reflectance signal is attributed to a fast dissolution of a stressed/strained interlayer beneath the SiO2/Si(1 1 1) interface. Similar effects were observed on thin thermal oxides (18.2 nm), grown on float zone silicon, as well as on ultra-thin native oxides (1.2 nm) on Czochralsky silicon. Native oxide covered samples showed an increased surface roughness in the course of interlayer dissolution while the surface is progressively covered with compounds of fluorinated silicon. The etch rate, determined by atomic force microscopy (AFM) and compared to the etch rate of bulk silicon, is increased by a factor of four. In the limit of extended etching, the known low etch rates for silicon in 40% NH4F are observed. Structural and chemical properties of the interfacial layer were analyzed by synchrotron radiation photoelectron spectroscopy (SRPES) which confirmed the presence of Si3+/4+ valence states throughout the interlayer and by near open-circuit potential (N-OCP) dark current measurements. As a result, oxide etch rates in NH4F in the pH-range 7–8 as well as the silicon interlayer depth can be assessed by in situ BAR. 相似文献
35.
The statistical lattice model has been proposed which permits one to take into account the change in the shape and surface morphology of the nanoparticle under the influence of the reaction media. The influence of monomolecular and dissociative adsorption on the particles equilibrium shape and surface morphology has been studied. It has been shown that by taking into account of attraction "adsorbate-metal" the reshaping of the initial hemispheric particle into cone-shaped one occurs induced by adsorption, similar to the experimentally observed reversible reshaping of active nanoparticles. The model reaction A+B(2) has been studied taking into account the roughening of the active particle surface and the spillover phenomena of the adsorbed A(ads) species over the support surface. 相似文献
36.
37.
MMA/BA/AA/HEMA无皂乳液体系的合成与性能表征 总被引:4,自引:0,他引:4
本文采用分步控浊结合种子人聚的新方法合成了MMA/BA/AA/HEMA无皂乳液体系,并对其粒径、耐水性以及贮存稳定性进行了研究。实验结果表明,该方法合成的无皂体系不仅固含量较高,反应稳定性和贮存稳定性较好,而且具有优良的耐水性。 相似文献
38.
In the present paper, the Fractional Step method usually used in single fluid flow is here extended and applied for the two-fluid model resolution using the finite volume discretization. The use of a projection method resolution instead of the usual pressure-correction method for multi-fluid flow, successfully avoids iteration processes. On the other hand, the main weakness of the two fluid model used for simulations of free surface flows, which is the numerical diffusion of the interface, is also solved by means of the conservative Level Set method (interface sharpening) (Strubelj et al., 2009). Moreover, the use of the algorithm proposed has allowed presenting different free-surface cases with or without Level Set implementation even under coarse meshes under a wide range of density ratios. Thus, the numerical results presented, numerically verified, experimentally validated and converged under high density ratios, shows the capability and reliability of this resolution method for both mixed and unmixed flows. 相似文献
39.
E.R. Ionita 《Applied Surface Science》2009,255(10):5448-5452
A small size radiofrequency plasma jet source able to produce cold plasma jets at atmospheric pressure is presented. The surface modification of polyethylene terephtalate, polyethylene and polytetrafluorethylene foils is performed by using a scanning procedure. The contact angle measurements reveal that the treatment leads to hydrophilicity increase. The roughening of surface, specific to each material is noticed. A significant improvement of adhesion is obtained as result of atmospheric plasma treatments. 相似文献
40.
S.A. Teys 《Surface science》2006,600(21):4878-4882
The vicinal Si(1 1 1) surface, inclined towards the direction, was investigated by scanning tunnelling microscopy and spot profile analysing low energy electron diffraction. It has been established that the surface, consisting of regularly spaced triple steps and (1 1 1) terraces with a width equal to that of a single unit cell of the Si(1 1 1)-7 × 7 surface structure, has the (7 7 10) orientation. An atomic model of the triple step is proposed. 相似文献