Features of the strain hardening of nickel titanium in the region of thermoelastic martensite transformation

The inheritance of strain hardening in a nickel titanium (TiNi) alloy that possesses shape memory has been studied using a sample subjected to plastic deformation in the austenite state prior to a transition to the martensite state. The results show that the strain hardening created in the TiNi alloy in the austenite state is not inherited in the martensite state and the sample behaves as if there were no significant plastic deformation. It is suggested that this behavior can be related to the fact that the alloy lattice defects (primarily, dislocations generated during pre-deformation in the austenite state) are not effective obstacles to the motion of domain boundaries in the martensite state.     

Quantum Electrodynamics of a Rydberg Atom Making Two-photon Transitions in the Binomial State of the Field in a Lossless Cavity

Abstract

The dynamic and statistical properties of a system of an effective two-level atom making two-photon transitions in the binomial state of the field in a lossless cavity are discussed. The binomial state enables the study of the development of the phenomenon of collapses and revivals of the Rabi oscillations as the field state is changed from a pure number state to a coherent state. This is because the binomial state, which is a pure number state in one limit, develops into a coherent state as some parameters are changed appropriately. The effect of Stark shifts arising due to the transitions to virtual levels are also investigated.     

Effects of the Binomial Field Distribution on Collapse and Revival Phenomena in the Jaynes-Cummings Model

Abstract

The dynamical properties of a two-level atom interacting with a single non-decaying mode of an electromagnetic field in a binomial state are studied. The statistical aspects of the field, such as intensity-intensity correlation and squeezing, are also investigated. The binomial state reduces to a pure number state and a pure coherent state in different limits. Hence it enables us to study how the sinusoidal Rabi oscillations in a pure number state develop to give rise to the phenomenon of collapse and revival which has been studied extensively in the coherent-state field. In addition, the binomial state exhibits squeezing for certain values of parameters, but it is not a minimum-uncertainty-product state.     

Measuring the refractive state of an eye based on the intensity of the retinal reflex

When examining the fundus of the eye with an ophthalmoscope, the intensity of the retinal reflex depends on the refractive state of the eye. In this study, application of this phenomenon for measuring the refractive state of the eye is demonstrated. First, a calibration curve relating the intensity of the retinal reflex and the refractive state was obtained using a model eye. Next, the intensity of the retinal reflex was measured while subjects were viewing a checker-board pattern, the distance of which was varied within the range from 0.17 to 1 m. Further, the relation between the refractive state and the optical power of the stimulus could be determined based on the measured light intensity and the calibration curve. Generally, the measured refractive state increased with the optical power of the stimulus. However, blinking and fluctuations in accommodation had undesired effects on the results.     

On the geometry of entangled states

The basic question that is addressed in this paper is finding the closest separable state for a given entangled state, measured with the Hilbert-Schmidt distance. While this problem is in general very difficult, we show that the following strongly related problem can be solved: find the Hilbert-Schmidt distance of an entangled state to the set of all partially transposed states. We prove that this latter distance can be expressed as a function of the negative eigenvalues of the partial transpose of the entangled state, and show how it is related to the distance of a state to the set of positive, partially transposed (PPT) states. We illustrate this by calculating the closest biseparable state to the W state and give a simple and very general proof for the fact that the set of W-type states is not of measure zero. Next we show that all surfaces with states whose partial transposes have constant minimal negative eigenvalue are similar to the boundary of PPT states. We illustrate this with some examples on bipartite qubit states, where contours of constant negativity are plotted on two-dimensional intersections of the complete state space.     

Spin Structures of the Hubbard Clusters and the Pseudogap

The spin and charge structures formed in the Hubbard model for a finite two-dimensional cluster have been studied in the mean field approximation. The self-consistent iterative procedure reduces an uncorrelated initial spin distribution into stable structures with spectral properties typical of stripes. It is shown that the density of states of the system for any doping has a sharp minimum at the Fermi level, the pseudogap. The pinning of the gap at the Fermi level is characteristic not only of a superconducting state, but also typical of a normal state of spin glasses. Our results support conception of the PG state as a state with frozen locally nematic spin structures of antiferromagnetic domains.     

Statistical Properties of the Even Binomial State

Abstract

In this paper we introduce the even binomal state, which interpolates between the even number state and the even coherent state. We consider the effect of this state on the Glauber second order correlation function. Both squeezing phenomena are discussed, i.e., normal squeezing and amplitude squared squeezing. The quasiprobability distribution functions (Wigner function and Q function) for such a state are also examined.     

Differential Relations between the Changes in the Strained State and the Level of Strains

We construct differential relationships between the variations of the parameters of the strained state (distortion tensor and the level of Cauchy strains) and the variations of the actual and normal configurations. The normal configuration is the objective reference configuration for the strained state and varies as a function all types of parameters of state (e.g., thermal, electric, and magnetic).     

Evaluating the State of a Complex Ergatic System Using the Example of a System for Ensuring the Uniformity of Measurements

Measurement Techniques - Evaluation of the state of a system for ensuring the uniformity of measurements is urgent and is necessary for monitoring and state forecasting. An approach is presented...     

半导体制冷最优工况的理论分析与实验研究

传统极限工况有最大制冷量工况和最大制冷系数工况,在此其间,必存在一特殊工况,使得既具有较大的制冷量,又具有较小的功耗,此工况即为“最优工况”。本文首先对半导体最优工况进行了理论分析,推导出最优电流的理论公式;再对一小型半导体制冷箱进行实验,通过调节电流改变工况,分析了8种工况实验下的性能参数变化情况,对实验数据进行回归分析,得出回归方程,从而找出最优电流对应的最优工况。在此工况下进行工作,即可获得较大的制冷量,又可消耗较小的功率,从而提高了半导体制冷器的制冷性能。实验结果与理论分析结果基本吻合。     

低热固相反应在材料合成中的应用

介绍了低热固相反应机制的研究进展、反应特点及影响低热固相反应的一些因素。重点阐述了低热固相反应在纳米材料、有机合成、电池材料、气敏材料以及其它一些功能材料中的应用。阐明低热固相反应确实是新型材料制备的一种简便、有效并有光明前景的方法。     

The Effect of Magnetic on the Properties of a Parabolic Quantum Dot Qubit

On the condition of electric-LO phonon strong coupling in a parabolic quantum dot, we obtained the eigen energies and the eigenfunctions of the ground state and the first excited state by using the variational method of Pekar type. This system in a quantum dot may be employed as a two-level quantum system qubit. When the electron is in the superposition state of the ground state and the first excited state, we obtained the space-time evolution of the electron density. The relations on the cyclotron frequency with the electron probability density and the period of oscillation are derived in a parabolic quantum dot.     

Influence of the LO Phonon Effect on the Transition Rate and the Spontaneous Emission Rate in Donor-Center Quantum Dot with Spherical Gaussian Confinement Potential

Based on Lee-Low-Pines transformation, the longitudinal optical (LO) phonon effect in a donor-center quantum dot with a spherical Gaussian confinement potential is studied. The energy expressions of the ground state and the first excited state are derived by using a Pekar-type variational method, and then, a superposition state of the two-level system is constructed. On the basis of Fermi Golden Rule, two kinds of the decoherence of superposition states caused by LO phonon effects are discussed, which are the spontaneous emission of LO phonon and the quantum transition from the ground state to the excited state by absorbing a LO phonon, respectively. The numerical results show that for the former, the superposition state can be suppressed by increasing the electron–phonon coupling constant, the dielectric constant ratio, or the dispersion coefficient. For the latter, it can be used to suppress the decoherence of the superposition state by increasing the dielectric constant ratio or decreasing the electron–phonon coupling constant, or using the low-temperature environment. This work enriches and improves the theoretical scheme to suppress the decoherence of a semiconductor quantum dot qubit caused by LO phonon-related effects.

     

Quantum effect of cooling down the environment temperature of mesoscopic LC circuit

We examine the quantum effect of cooling down the environment temperature of mesoscopic LC circuit, and find that the ground state of the circuit is no longer in the thermo vacuum state, but in a negative binomial state. We calculate energy of the circuit in this new state, which increases with the cooling of the environment.     

On the assumptions of the generalized plane stress problem and the Filon average

In this article, we prove that the assumption of vanishing normal stress for the generalized plane stress problem can be further weakened, so that the normal stress is harmonic. The stress state under this harmonic assumption can also be decomposed into the plane stress state and the shear stress state. Finally, a necessary and sufficient condition is presented for the existence of the biharmonic Airy stress function for the Filon averaged in-plane stresses, which is shown to be weaker than the assumption of the harmonic normal stress.     

On the extrapolation behavior of empirical equations of state

Generally, the extrapolation behavior of empirical equations of state is regarded as poor, but it can be shown that state-of-the-art equations of state yield reliable results well beyond the range where they were fitted to experimental data. During the past years a new generation of highly accurate equations of state which yield reasonable results even up to the limits of chemical stability of the considered substances has been developed. In this paper, the positive influence of recent methods for the development of equations of state on their extrapolation behavior is discussed. The influence of the mathematical structure on the extrapolation characteristics is analyzed and requirements for a reasonable behavior up to extreme temperatures and pressures are formulated. As possible ways for assessment of the extrapolation behavior of an equation of state, comparisons with experimental data at very high pressures and temperatures and with theoretically predicted features of the so-called “ideal curves” of a fluid are discussed. Finally, the current status of our knowledge of the extrapolation behavior of empirical equations of state is summarized and its shortcomings are pointed out.     

An Equation of State for the Hard-Sphere Chain Fluid Based on the Thermodynamic Perturbation Theory of Sequential Polymerization

New equations of state for freely jointed hard-sphere chain fluids are developed. The equations of state are based on the thermodynamic perturbation theory. The new equations of state use the contact values of the radial distribution function (RDF) for monomer–dimer mixtures, which is derived from the multidensity Ornstein–Zernike theory. These RDFs are composed of a monomer reference term, the Carnahan–Starling or the Percus–Yevick expression, and an additional bond contribution. These equations of state are then extended to real fluids. To calculate the phase equilibrium properties of nonassociating chain fluids, a dispersion contribution is added to the repulsive hard-chain reference term. With the new equations of state of chain fluids supplemented with the dispersion term, the vapor pressures and the coexisting densities of several real fluids are calculated.     

Systemic principals of research of functional states of the gas-man operator while working in the desert

This work describes functional state of the gas-man operator while working in the desert. Under the functional state, one understands the state of the operator that is changing during the work shifts. The most important characteristics of the operator's functional state are work capacity and fatigue. These are two sides of the same coin. The more the fatigue is, the less is the work capacity. In spite of the broad interest to these phenomena, ther is still not a precise and reliable way to measure them. The present article focuses on some aspects of this important issue from the activity theory point of view.     

The decomposed form of the three-dimensional elastic plate

Summary. In 1992, Gregory [1] gave a rigorous proof about the decomposed form when stress is anti-symmetrical about the mid-plane. His proof is dependent on his previous works [3], [4], i.e., the Papkovich-Fadle eigenfunction expansion of bi-harmonic functions. In this paper, we give a new proof concisely and directly, which is independent of the Papkovich-Fadle expansion, when stress is anti-symmetrical about the mid-plane. The general state of stress in the plate can be decomposed into three parts: the interior state, the shear state and the Papkovich-Fadle state.     

Influence of the state of interfaces on the character of local displacements in fault-block and interfacial media

We have studied the possibility of producing a directed action upon the process of local stress relaxation in interfacial media occurring in a complex stressed state by changing the state of boundaries between structural elements. The experiments were performed on the ice sheet of Lake Baikal, which represents a hierarchically organized fault-block structure and belongs to the class of interfacial media. It is shown that, by changing the state of boundaries between structural elements, it is possible to influence the regime of deformation of the interfacial medium as a whole. The general features of the observed effect are confirmed within the framework of a theoretical model.