Comments on the Morita equivalence

It is known that the noncommutative Yang-Mills (YM) theory with periodical boundary conditions on a torus at a rational noncommutativity parameter value is Morita equivalent to the ordinary YM theory with twisted boundary conditions on a dual torus. We give a simple derivation of this fact. We describe the one-to-one correspondence between these two theories and the corresponding gauge invariant observables. In particular, we show that under the Morita map, the Polyakov loops in the ordinary YM theory are converted to the open noncommutative Wilson loops discovered by Ishibashi, Iso, Kawai, and Kitazawa.     

On the independence of the thermodynamic limit on the boundary conditions in quantum statistical mechanics

The problem of the independence of the thermodynamic limit on the boundary conditions is considered in the framework of functional integration. For every domain and every boundary condition in a sufficiently large class a functional measure is constructed and the Feynman-Kac-like formula for the statistical operator written down. Making use of some volume-independent estimates for the Green function of the heat equation, the thermodynamic limit along convex domains for general boundary conditions is proved to exist and to be equal to that for Dirichlet conditions.     

On the influence of the nuclear quadrupole moment on the β-decay of deformed nuclei

It is pointed out that in none of the previous treatments of the quadrupole interaction in β-decay have the relevant boundary conditions on the final state been recognized or observed. The discrepancy between a purely perturbative treatment and some slightly more exact treatments is shown to stem, ultimately, from this circumstance. Similarly, the basic argument behind the prediction of discontinuities in the β-spectra of deformed nuclei is incompatible with the pertaining boundary conditions on the final state. A straightforward adherence to the proper boundary conditions results in discontinuities which, in general, are much smaller than previously anticipated. The failure to see a predicted discontinuity in a reported preliminary experiment on the β-decay of ¹⁷⁰Tm is entirely understandable, without any assumption of some kind of further hindrance in the decay.     

Binaural intelligibility prediction based on the speech transmission index

Although the speech transmission index (STI) is a well-accepted and standardized method for objective prediction of speech intelligibility in a wide range of environments and applications, it is essentially a monaural model. Advantages of binaural hearing in speech intelligibility are disregarded. In specific conditions, this leads to considerable mismatches between subjective intelligibility and the STI. A binaural version of the STI was developed based on interaural cross correlograms, which shows a considerably improved correspondence with subjective intelligibility in dichotic listening conditions. The new binaural STI is designed to be a relatively simple model, which adds only few parameters to the original standardized STI and changes none of the existing model parameters. For monaural conditions, the outcome is identical to the standardized STI. The new model was validated on a set of 39 dichotic listening conditions, featuring anechoic, classroom, listening room, and strongly echoic environments. For these 39 conditions, speech intelligibility [consonant-vowel-consonant (CVC) word score] and binaural STI were measured. On the basis of these conditions, the relation between binaural STI and CVC word scores closely matches the STI reference curve (standardized relation between STI and CVC word score) for monaural listening. A better-ear STI appears to perform quite well in relation to the binaural STI model; the monaural STI performs poorly in these cases.     

Harmful Substances on the Opera Stage: Possible Negative Effects on Singers'' Respiratory Tracts

Objective, quantitative information is lacking in the medical community about actual working conditions for professional singers onstage, and moreover, about which conditions are safe. Physicians, speech-language pathologists, and speech scientists focusing on laryngology should have relevant information about the opera as workplace and the medical sequelae of unhealthy environments. We describe five toxic substances to which singers presenting to our clinics were exposed while working professionally on the opera stage: (1) aromatic diisocyanates, (2) penicillium frequentans in cork granulate, (3) formaldehyde in cork granulate, (4) cobalt and aluminum (pigment components), and (5) quartz sand capable of entering the alveolae. Biological considerations and clinical data for some subjects suggest a direct causal link between the exposures and the patients' complaints and findings. Our observations suggest that whenever singers complain about deleterious conditions such as dry and hot onstage climate or suspicion of the presence of harmful substances, the specific conditions existing in the theater in question should be investigated. Harmful substances are not only poorly tolerated by singers, but also they should be preventable.     

Two questions on the geometry of gauge fields

We first show that a theorem by Cartan that generalizes the Frobenius integrability theorem allows us (given certain conditions) to obtain noncurvature solutions for the differential Bianchi conditions and for higher-degree similar relations. We then prove that there is no algorithmic procedure to determine, for a reasonable restricted algebra of functions on spacetime, whether a given connection form satisfies the preceding conditions. A parallel result gives a version of Gödel's first incompleteness theorem within an (axiomatized) theory of gauge fields.     

Some photoeffects on the semiconductor surface under sub-bandgap illumination

Surface photovoltage as well as surface photoconductivity response on the light intensity under sub-bandgap illumination is treated. The influence of the surface barrier height, the density of surface traps, the bulk electron density as well the temperature on the surface photovoltage (surface photoconductivity) is analysed. The detectability conditions are included. The consequences of detectability conditions are discussed.     

Note on the quantum Hall Hamiltonian in cylinder geometry

A set of sufficient conditions is formulated for the integer quantum Hall effect to occur in a system of independent electrons in a random potential on the surface of a cylinder of finite length with perpendicular strong magnetic field. The relation to previous formulations of related conditions and recent numerical results is discussed.Dedicated to Professor W. Brenig on the occasion of his 60th birthday     

Effects of hydrostaticity on the structural stability of carbonates at lower mantle pressures: the case study of dolomite

We have conducted high pressure far-infrared absorbance and Raman spectroscopic investigations on a natural iron-free dolomite sample up to 40?GPa. Comparison between the present observations and literature results unraveled the effect of hydrostatic conditions on the high pressure dolomite polymorph adopted close to 40?GPa, i.e. the triclinic Dol-IIIc modification. In particular, non-hydrostatic conditions impose structural disorder at these pressures, whereas hydrostatic conditions allow the detection of an ordered Dol-IIIc vibrational response. Hence, hydrostatic conditions appear to be a key ingredient for modeling carbon subduction at lower mantle conditions. Our complementary first-principles calculations verified the far-infrared vibrational response of the ambient- and high pressure dolomite phases.     

薄膜系列实验的教学研究

从薄膜制备、生长过程动态分析以及形貌表征3方面设计了薄膜系列实验.用离子束溅射制备金属薄膜,研究了制备条件对溅射速率的影响,测量了薄膜生长过程中电阻的变化,用扫描隧道显微镜或原子力显微镜观测薄膜的表面形貌,并分析不同制备条件得到的薄膜的表面形貌特征.     

XX model on the circle

We diagonalize the XX model with a finite number of spins and periodic boundary conditions. We solve for the ground state, focus on the rapidity of the convergence to the thermodynamic limit and study the features of multipartite entanglement.     

辐射背景对岩石受力热红外光谱变化影响的实验研究

研究表明,岩石在加载过程中表面的红外辐射随应力发展而变化,而辐射信息的有效提取与辐射背景存在密切关系。通过理论分析不同实验环境对岩石受力热红外光谱变化影响,开展了花岗岩在室内外环境下的受力热红外光谱观测实验,分析了不同辐射背景下岩石红外辐射与应力的相关性以及由应力引发的辐射变化信息的强弱差异,并对两种环境下岩石应力热红外探测的优势波段进行了对比分析。结果表明,辐射背景对岩石受力热红外光谱探测结果有重要影响,室外环境因背景辐射较弱,相同应力作用下的红外辐射变化更加显著,与应力之间的相关程度更高,优势波段区间更宽,更加有利于岩石应力的热红外探测。8.0~11.8 μm波段是利用热红外遥感监测地表花岗岩应力变化的优势波段。     

Dimer problem on the cylinder and torus

We obtain explicit expressions of the number of close-packed dimers and entropy for three types of lattices (the so-called 8.8.6, 8.8.4, and hexagonal lattices) with cylindrical boundary condition and the entropy of the 8.8.6 lattice with toroidal boundary condition. Our results and the one on 8.8.4 and hexagonal lattices with toroidal boundary condition by Salinas and Nagle [S.R. Salinas, J.F. Nagle, Theory of the phase transition in the layered hydrogen-bonded SnCl²⋅2H₂O crystal, Phys. Rev. B 9 (1974) 4920-4931] and Wu [F.Y. Wu, Dimers on two-dimensional lattices, Inter. J. Modern Phys. B 20 (2006) 5357-5371] imply that the 8.8.6 (or 8.8.4) lattices with cylindrical and toroidal boundary conditions have the same entropy whereas the hexagonal lattices have not. Based on these facts we propose the following problem: under which conditions do the lattices with cylindrical and toroidal boundary conditions have the same entropy?     

On Solution of the Integrable Initial Boundary Value Problem for KdV Equation on the Semi-axis

This paper is concerned with the Korteweg-de Vries (KdV) equation on the right semi-axis. The initial boundary value problem with inhomogeneous integrable boundary conditions is studied. We show that, under some conditions on the initial data the problem has a solution and provide the procedure for constructing this solution. The procedure is based on the inverse spectral method and consists of several steps reducing to either solving some linear problems or calculations via some explicit formulas.     

A power counting theorem for Feynman integrals on the lattice

A convergence theorem is proved, which states sufficient conditions for the existence of the continuum limit for a wide class of Feynman integrals on a space-time lattice. A new kind of a UV-divergence degree is introcduced, which allows the formulation of the theorem in terms of power counting conditions.     

Effect of boundary conditions on quantum-anti-dots in the presence of a magnetic field

Many people have studied the conductance properties through an array of anti-dots, especially since the observation of Weiss oscillations. In most cases, however, in which the recursive Greenźs functions are used on a spatial lattice, periodic boundary conditions are employed. In this paper, we analyse the effects of boundary conditions and magnetic field on the conductance behavior in a number of anti-dot-shaped, GaAs/AlGaAs 2DEG quantum systems. The effect of periodic boundary conditions causes a reduction in the overall conductance. The effect of changing the boundary conditions is more profound for lower numbers of anti-dots.     

Influence of thunderstorm atmospheric conditions on the properties of ball lightning

Rank-correlation methods are used to investigate the influence of thunderstorm atmospheric conditions on the lifetime (observation time) and diameter of ball lightning on the basis of an analysis of observations from the Stakhanov-Cole-Bychkov ball lightning PC database. For the analysis ball lightning events are ranked by diameter, the weather conditions are ranked in relation to humidity, which correlates with the charge state of the atmosphere, and thunderstorm conditions are ranked in relation to the electric field of the atmospheric ground layer. A statistical analysis shows that the lifetime and diameter of ball lightning decrease under conditions of increasing humidity and increasing electric field. The plausibility of this result from the standpoint of various existing ball lightning models is discussed. Zh. Tekh. Fiz. 67, 117–122 (April 1997)     

Effect of the dependence of the specular reflectance on the angle of incidence of electrons on the impedance

We obtain the solution to the problem of the skin effect in a metal with specular-diffusion boundary conditions for arbitrary values of the anomaly parameter in the form of the Neumann series. For this purpose, we develop a method based on the idea of representation of not only the boundary condition imposed on the field (as is conventionally done), but also the boundary condition imposed on the distribution function, in the form of a source. The specular reflectance is an arbitrary function of the angle of incidence of electrons on the metal surface.     

Influence of random initial conditions on the evolution of nonlinear systems

The influence of randomly distributed initial conditions on the evolution of dynamical systems is analyzed. It is shown that for systems exhibiting a long induction period followed by a stage of fast evolution, the randomness of the initial conditions can deeply affect the macroscopic evolution law.     

Skin spectrophotometry under the islet photothermal effect on the epidermal permeability

The results of experimental investigation of an increase in the epidermal barrier permeability are presented. The results are obtained using the method based on the creation of permeability microzones (islets) during the local thermal action on stratum corneum. It is shown that the epidermal barrier permeability considerably increases under the island photothermal effect and application of various clearing agents. Detailed spectrophotometric investigations of skin under the conditions of a partial violation of the epidermis barrier functions due to the island effect and introduction of various immersion agents in the skin are presented. The effect of various conditions of the object illumination on the dynamics of spectra is analyzed. A common behavior of the dynamics of the spectra of all kinds during clearing is revealed. Possible mechanisms accompanying the optical clearing process under the island photothermal effect are discussed.