共查询到20条相似文献,搜索用时 46 毫秒
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针对传统JJY型分光计调节中的困难,在确保分光计原有结构和功能不变的前提下,设计、制作出可实现分光计简易调节的辅助装置,极大地提高了教学效率。 相似文献
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本文以JJY型分光计为例,对分光计的聚焦与光轴倾斜度这两方面的调节做了系统论述.同时根据分光计的结构特点与调节本质,对传统的“各半调节法”进行改进,提出新的“分别调节法”,并在此基础上对仪器也做出了一些完善,使调节效率得到提高. 相似文献
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为解决目前教学用分光计操作中存在的诸多缺陷, 我们改进了教学用分光计装置, 使它更易于调节和
演示、 让学生更直观地了解分光计的调节及测量过程 相似文献
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分析了分光计中望远镜调节原理,归纳与总结了望远镜光轴、载物台都垂直于分光计中心轴的多种调节方法,有利于实验教学。 相似文献
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Step photostereoisomerization of solutions of dicarbocyanine dyes was studied by laser photolysis. It is shown that, due to excitation, primary mono-cis-photoisomers are formed (a one-step process), whose excitation results in the formation of a γβ-di-cis-isomer (a two-step process). It was proved that the γβ-di-cis-isomer is formed mainly from a γ-mono-cis-isomer. The relaxation of the ground state of the γβ-di-cis-isomer to the ground state of a stable all-trans-isomer occurs in steps via two channels, in which γ-and β-mono-cis-isomers arise as intermediate products. The relaxation rates of both channels are different. The shift of the wavelength related to the maximum of absorption in the spectra of the primary and secondary isomers relative to that of the all-trans-isomer depends on the electron-donor ability of terminal groups. Quantum-chemical calculations of changes in the energies of the ground and first excited singlet states of a molecule, caused by the rotation around several bonds in the methine chain, were carried out. 相似文献
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Igor Vilfan 《Surface science》1996,350(1-3):329-335
Step patterns on vicinal (2 × 1) reconstructed surfaces of noble metals Au(110) and Pt(110), miscut towards the (100) orientation, are investigated. The free energy of the reconstructed surface with a network of crossing opposite steps is calculated in the strong chirality regime when the steps cannot make overhangs. It is explained why the steps are not perpendicular to the direction of the miscut but form in equilibrium a network of crossing steps which make the surface to look like a fish skin. The network formation is the consequence of competition between the — predominantly elastic — energy loss and entropy gain. It is in agreement with recent scanning tunnelling microscopy observations on vicinal Au(110) and Pt(110) surfaces. 相似文献
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A statistical mechanics model for a faceted crystal is the 3D Ising model at zero temperature. It is assumed that in one octant all sites are occupied by atoms, the remaining ones being empty. Allowed atom configurations are such that they can be obtained from the filled octant through successive removals of atoms with breaking of precisely three bonds. If V denotes the number of atoms removed, then the grand canonical Boltzmann weight is q
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, 0<q<1. As shown by Cerf and Kenyon, in the limit q1 a deterministic shape is attained, which has the three facets (100), (010), (001), and a rounded piece interpolating between them. We analyse the step statistics as q1. In the rounded piece it is given by a determinantal process based on the discrete sine-kernel. Exactly at the facet edge, the steps have more space to meander. Their statistics is again determinantal, but this time based on the Airy-kernel. In particular, the border step is well approximated by the Airy process, which has been obtained previously in the context of growth models. Our results are based on the asymptotic analysis for space-time inhomogeneous transfer matrices. 相似文献
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Wojciech De Roeck Abhishek Dhar François Huveneers Marius Schütz 《Journal of statistical physics》2017,167(5):1143-1163
We consider two types of strongly disordered one-dimensional Hamiltonian systems coupled to baths (energy or particle reservoirs) at the boundaries: strongly disordered quantum spin chains and disordered classical harmonic oscillators. These systems are believed to exhibit localization, implying in particular that the conductivity decays exponentially in the chain length L. We ask however for the profile of the (very slowly) transported quantity in the steady state. We find that this profile is a step-function, jumping in the middle of the chain from the value set by the left bath to the value set by the right bath. This is confirmed by numerics on a disordered quantum spin chain of 9 spins and on much longer chains of harmonic oscillators. From theoretical arguments, we find that the width of the step grows not faster than \(\sqrt{L}\), and we confirm this numerically for harmonic oscillators. In this case, we also observe a drastic breakdown of local equilibrium at the step, resulting in a heavily oscillating temperature profile. 相似文献
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A model is suggested to describe the fringe shift which occurs due to the phase variations of cladded glass fibre introduced between the two plates of the liquid wedge interferometer illuminated with a He–Ne laser. The fringe shift of the phase object which appears in the denominator of the Airy distribution formula of the multiple beam interference is represented in the harmonic term. An experiment is conducted using liquid wedge interferometer where the step index glass fibre of a nearly quadratic thickness variation is introduced between the two plates of the interferometer. The obtained fringe shift shows a good agreement with the proposed quadratic model. The Matlab code is written to plot the interferometer fringes comprising the shift of the step index fibre. Secondly, recognition of elliptical fibres is outlined using tomographic imaging. Finally, results and concluding remarks are given. 相似文献
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N. N. Peschanskaya 《Physics of the Solid State》2001,43(8):1478-1482
The variation of step deformation kinetics in solids is studied as a function of morphological factors. Oscillations of creep rate at micrometer increments of the amount of deformation, which reflect the step nature of the process, are investigated from an interferogram. It is shown that the plasticization of polymethyl methacrylate by dibutyl phthalate blurs the steps, while their height varies insignificantly. The results are explained using the concept of the netlike structure of amorphous polymers. The data obtained confirm the universal nature of jumps as a mode of evolution of deformation in various solids. The jumps reflect the cooperative nature of motion of kinetic units, and the regular variation of the characteristics of the jumps lends support to the definition of creep as a process of structural self-organization. 相似文献
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The step line tension in electrochemical systems differs conceptually from the line tension on metals in the vacuum because it refers to different boundary conditions. A procedure is established for calculating the electrochemical line tension and is applied to a novel model of the interface comprising both a stepped metal electrode and an electrolyte solution. To first order, the potential dependence of the line tension is governed by the energy of the step dipole in the electric field of the space charge in the solution. 相似文献
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