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1.
Diffraction patterns produced by quasi-elastically backscattered electrons focused in a thin single-crystal Si(100)2×1 near-surface
layer have been studied. The measurements performed in the 0.6–2-keV range are compared with calculations made in the single-scattering
cluster approximation. This model is shown to describe adequately the experiment. An analysis is made of the relation among
the diffraction patterns observed for different silicon faces, and of the effect of the primary-electron beam orientation.
The relations governing the focusing of quasi-elastically backscattered electrons escaping from the crystal along the main
crystallographic directions have been established. The various aspects of the effect for backscattered electrons undergoing
inelastic interaction with the electron subsystem of the crystal have been investigated.
Fiz. Tverd. Tela (St. Petersburg) 40, 1364–1369 (July 1998) 相似文献
2.
3.
本文利用荧光光谱和园二色光谱了新开花粉蛋白的盐酸胍去折叠过程。结果显示:新开花粉蛋白的盐酸胍去折叠是一个只包含天然蛋白和变性终态的二态过程,与已经报道的天花粉蛋白的盐酸胍去折叠的过程不同。 相似文献
4.
The growth of epitaxial films of Pb1 − x
Sn
x
Se solid solutions of different chemical compositions (x = 0.02–0.05) on freshly cleaved BaF2(111) faces and the structure of these films have been investigated. Photosensitive p-n homojunctions have been prepared on their basis. The homojunctions are fabricated in a unified technological cycle without
breaking vacuum based on n- and p-type films of high structural quality (W
1/2 = 90–100″) that were grown using an additional selenium vapor source. The photosensitivity peak is found to shift to longer
wavelengths with an increase in the Sn content in the films grown; this effect is explained by narrowing the band gap with
a change in the composition. 相似文献
5.
Review of nanofluids for heat transfer applications 总被引:2,自引:0,他引:2
Saeid Vafaei 《中国颗粒学报》2009,7(2)
Research on nanofluids has progressed rapidly since its enhanced thermal conductivity was first repotted about a decade ago,though much controversy and inconsistency have been reported,and insufficient understanding of the formulation and mechanism of nanofluids further limits their applications.This work presents a critical review of research on heat transfer applications of nanofluids with the aim of identifying the limiting factors so as to push forward their further development. 相似文献
6.
A study is made of the features arising in the spatial distributions of reflected electrons as a result of a focusing effect.
Experiments are conducted on single-crystal Mo (100) with primary electron energies of 0.5–2 keV and detection of electrons
which lose fixed amounts of energy up to 300 eV. An analysis of the data establishes the dependence of the electron focusing
efficiency on the amount of energy loss. It is shown that when electrons are reflected with single losses through plasmon
excitation, the magnitude of the effect is determined mainly by the average number of scattering atoms encountered by an electron
along its path to the surface. When the energy losses are high, defocusing owing to multiple elastic and inelastic scattering
of the electrons is found to predominate.
Zh. Tekh. Fiz. 68, 128–133 (June 1998) 相似文献
7.
Faradzhev NS Perry CC Kusmierek DO Fairbrother DH Madey TE 《The Journal of chemical physics》2004,121(17):8547-8561
The kinetics of decomposition and subsequent chemistry of adsorbed CF(2)Cl(2), activated by low-energy electron irradiation, have been examined and compared with CCl(4). These molecules have been adsorbed alone and coadsorbed with water ice films of different thicknesses on metal surfaces (Ru; Au) at low temperatures (25 K; 100 K). The studies have been performed with temperature programmed desorption (TPD), reflection absorption infrared spectroscopy (RAIRS), and x-ray photoelectron spectroscopy (XPS). TPD data reveal the efficient decomposition of both halocarbon molecules under electron bombardment, which proceeds via dissociative electron attachment (DEA) of low-energy secondary electrons. The rates of CF(2)Cl(2) and CCl(4) dissociation increase in an H(2)O (D(2)O) environment (2-3x), but the increase is smaller than that reported in recent literature. The highest initial cross sections for halocarbon decomposition coadsorbed with H(2)O, using 180 eV incident electrons, are measured (using TPD) to be 1.0+/-0.2 x 10(-15) cm(2) for CF(2)Cl(2) and 2.5+/-0.2 x 10(-15) cm(2) for CCl(4). RAIRS and XPS studies confirm the decomposition of halocarbon molecules codeposited with water molecules, and provide insights into the irradiation products. Electron-induced generation of Cl(-) and F(-) anions in the halocarbon/water films and production of H(3)O(+), CO(2), and intermediate compounds COF(2) (for CF(2)Cl(2)) and COCl(2), C(2)Cl(4) (for CCl(4)) under electron irradiation have been detected using XPS, TPD, and RAIRS. The products and the decomposition kinetics are similar to those observed in our recent experiments involving x-ray photons as the source of ionizing irradiation. 相似文献
8.
Vijay NS Bhagawati-Prasad Evy De Leenheer Nadine P Keefe Lorna A Ryan Jennifer Carlring Andrew W Heath 《Journal of immune based therapies and vaccines》2010,8(1):1
Active vaccination can be effective as a post-exposure prophylaxis, but the rapidity of the immune response induced, relative
to the incubation time of the pathogen, is critical. We show here that CD40mAb conjugated to antigen induces a more rapid
specific antibody response than currently used immunological adjuvants, alum and monophosphoryl lipid A™. 相似文献
9.
M. V. Gomoyunova I. I. Pronin D. A. Valdaitsev N. S. Faradzhev 《Physics of the Solid State》2000,42(3):554-560
The mechanism of the formation of the diffraction patterns upon inelastic reflection of mean-energy electrons from the VSe2(0001) layered crystal has been investigated. It is found that the strong scattering of electrons by short atomic chains of the Se-V-Se layer triads leads to the weakening of electron focusing and the enhancement of diffraction scattering in deeper layers, which gives rise to the Kikuchi lines. It is demonstrated that, at an energy of 2 keV, the diffraction pattern is adequately described by the cluster model of single scattering. The atomic structure of thin near-the-surface layer of VSe2 has been investigated by the computer simulation of experimental data. 相似文献
10.
M. V. Gomoyunova I. I. Pronin D. A. Valdaitsev N. S. Faradzhev 《Physics of the Solid State》2002,44(6):1176-1180
The growth of cobalt disilicide on the Si(100) surface by reactive epitaxy at T=350°C was studied within the 10–40 ML cobalt coverage range. A new method of mapping the atomic structure of the surface layer by inelastically scattered medium-energy electrons was employed. The films thus formed were shown to consist of CoSi2(221) grains of four azimuthal orientations turned by 90° with respect to one another. This domain structure originates from substrate surface faceting by (111) planes, a process occurring during silicide formation. B-oriented CoSi2(111) layers grow epitaxially on (111) facets. 相似文献