Indexing schemes for quasilattices

Various schemes have been proposed and employed, which extend the method of indexing lattice vectors and reciprocal-lattice vectors, so that it can be used in the context of quasicrystals. The concept of the generalized inverse of a matrix provides an elegant unified approach to the vectors and reciprocal vectors of quasilattices, and their associated zone laws and inflation rules. We present a survey, from the viewpoint provided by the concept of the Moore–Penrose inverse, of the indexing problem for quasicrystals.     

Electronic properties of one-dimensional quasilattices

We study the on-site model of a new class of one-dimensional qusiperiodic lattices, for which the substitution rules areBBA, andABAB. By means of the renormalization-group approach, a interesting multifractal specrral behavior has been found, which has been confirmed by numerical simulation. A Cantor-like energy spectra is obtained by using the Kohmoto-Kadanaff-Tang (KKT) renormalization-group method. Three kinds of wave-function behavior (extended, localized, and intemediate states) are definitely found.     

Bravais quasilattices of icosahedral quasicrystals

A classification of icosahedral quasicrystals based the mutual-local-derivability (MLD) concept is performed. There are eighteen MLD classes within the reservation that the faces of the hyperatoms (windows) are perpendicular to the two-, three-, or fivefold axes. Each MLD class has a representative member to be called the Bravais quasilattice from which the structure of each member of the class is derived by decorating it according to a local rule depending on the member.     

一道力学题错解的辩析

[题目]:一质量为M,倾角为α高为h的光滑斜面体放在光滑水平面上,在斜面顶端有一质量为m的物块,让物块由静止开始下滑,求物块滑到底端时的速度是多少? 原解:如图1,设物块滑至斜面底端时     

学生在学习中常见错误类型分析

学生解题时,常出现各种各样的错误,大致上可归为以下几种类型.1 概念不清而致误 正确理解概念是正确解题的关键,有的同学常因概念认识不清,导致错误的解答.1.1 不顾条件用物理模型致误 任何模型均具有局限性,不存在无局限性的模型,忘了它的局限性就会犯错误.如:质点模型,当一个物体的形状、大小在所研究的     

让思维在"错"中飞翔

听过一些精心打造的公开课，授课教师高超的艺术令人叹为观止：他们或有深不可测的思维技巧，或是天衣无缝的师生配合，或是不差毫厘的时间安排……这样“完美”的课真的“无缺”吗？求真务实是我们共同的追求，但物理课上我们认为应允许出“错”，并要让学生的思维在错中绽放，在错中觅得真谛。     

对教材中两个例题的纠正

五年制专科全国通用教材[技术物理基础]第一册第124页有一例题的解答是错误的,原题及解答如下: 手控刹车结构如图1所示,若CB=0.7m BO=0.2m手的拉力F=300N,求作用于AB杆上的推力.分析与解答:取CO杆为研究对象,它     

以错因为载体,努力提高教学效率

在学习过程中,学生不可避免地犯各种各样的错误,学习的过程始终伴随着对错误的发现、分析和纠正.实际上许多正确的观念和行为是在对错误的观念和行为的否定中得以形成的.钱学森先生曾说过:"正确的结果是从大量错误中得来的;没有大量的错误作阶梯,也就登不上最后正确结果的宝座."     

常见的错误矢量式及其分析纠正

指出了某些教材、资料中的错误的矢量式,并进行了分析及纠正．     

避开"运动合成与分解"的误区

“速度关联类”问题的求解，往往是高考命题的切入点，而找寻运动物体之间的关联量则是考生普遍认为的难点．下面笔者就人民教育出版社的《普通高中课程标准实验教科书物理2必修》中的第六章“曲线运动”的第二节——“运动的合成与分解”，     

E.Dinc的双除数因子-比光谱导数法的错误性

E .Dinc等人曾提出双除数因子 比光谱导数法 ,并应用于两种三元混合体系的同时测定。实际上 ,双除数因子 比光谱导数法是完全错误的 ,它不能成功应用于三元混合体系的同时测定。文章从理论上和实践上证明了E .Dinc方法的错误性。     

时间的客观性、钟的同步与相对论的错误

定义时间和钟的同步。设计钟的同步的实现方法。指出相对论有关时间问题的错误。     

Radionuclides in deposition in the Ignalina NPP region in 2005

Results of radionuclide activity concentration measurements in deposition and ground-level air conducted at the station of the Institute of Physics situated 3.5 km from the Ignalina Nuclear Power Plant (Ignalina NPP) in 2005 are analyzed. Atmospheric depositional fluxes of ⁷Be, ⁶⁰Co and ¹³⁷Cs are estimated. Radionuclide particle deposition rates are calculated. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model of the global dispersion and deposition is used to explain variations in the ¹³⁷Cs activity concentration in the ground-level air in the Ignalina NPP region in 2005. An increase in the ¹³⁷Cs activity concentration of up to 17.4 μBq m⁻³ on 30 October-5 November is studied. Modelling results show that the Chernobyl NPP Unit 4 Sarcophagus and the radiocaesium resuspension from the Chernobyl NPP accident polluted regions are sources of ¹³⁷Cs to the environment of the Ignalina NPP. Results on solubility in water of aerosols — carriers of ¹³⁷Cs — are discussed.     

Thermal convection in Rivlin-Ericksen elastico-viscous fluid in porous medium in hydromagnetics

The thermal instability of a layer of Rivlin-Ericksen elastico-viscous fluid in porous medium acted on by a uniform magnetic field is considered. For stationary convection, Rivlin-Ericksen elastico-viscous fluid behaves like a Newtonian fluid. The magnetic field is found to have stabilizing effect whereas medium permeability has destabilizing effect. The magnetic field introduces oscillatory modes in the system, A sufficient condition for the non-existence of overstability is also obtained.