Analysis of the effects of physical task stress on the speech signal

Physical task stress is known to affect the fundamental frequency and other measurements of the speech signal. A corpus of physical task stress speech is analyzed using a spectrum F-ratio and frame score distribution divergences. The measurements differ between phone classes, and are greater for vowels and nasals than for plosives and fricatives. In further analysis, frame score distribution divergences are used to measure the spectral dissimilarity between neutral and physical task stress speech. Frame scores are the log likelihood ratios between Gaussian mixture models (GMMs) of physical task stress and of neutral speech. Mel-frequency cepstral coefficients are used as the acoustic feature inputs to the GMMs. A Laplacian distribution is fitted to the frame scores for each of ten phone classes, and the symmetric Kullback-Leibler divergence is employed to measure the change in distribution from neutral to physical task stress. The results suggest that the spectral dissimilarity is greatest for the second level of a four level exertion measurement, and that spectral dissimilarity is greater for nasal phones than for plosives and fricatives. Further, the results suggest that different phone classes are affected differently by physical task stress.     

The quantization of the relativistic string

The classical field-dependent parametrization covariant Hamiltonian formulation of the open and the closed string is discussed. The formalism is not applicable to the open string. A conformally covariant formalism is developed for the open string. The Rohrlich gauge conditions are justified and applied. The parametrization of classical solutions is not uniquely fixed; the generators of rigid time translation in the parameter space remain first class. The constraints and gauge conditions are taken into account in the quantum theory as conditions on physical states. The required invariance of physical states under rigid displacement of parameter time leads to a mass superselection rule. The set of physical string quantum states is analogous to the set of states constructed by Di Vecchia, Del Guidice, and Fubini. A recursive construction is presented which permits the counting of physical states of any given mass, spin, and parity. Physical states lie on linearly rising Regge trajectories with one universal slope. The intercept of the leading trajectory is constrained only by the requirement that there be no tachyonic physical states. The quantization is carried out in four space-time dimensions.Supported by NSF Grant No. MPS74-15246 and DFG/Az 287/6. A portion of this work has been accepted by Syracuse University in partial fulfillment of the requirements of the doctorate degree.     

固液混合装药热传导特性对其安全性影响的计算研究

固液混合装药物理参数是影响装药安全性的主要因素之一,利用混合炸药计算物理参数的方法,计算了几种典型配比装药的物理参数,根据能量守恒方程对不同物理参数的装药进行数值模拟。计算得到:在温度载荷相同的条件下,不同的物理参数对其温度响应有较大的差别,说明分析固液混合装药安全性时,应考虑装药不同比例对其安全性的影响,才能真实反应热点能量演化过程,为分析固液混合装药的安全性提供一定的理论依据。     

A quantum-mechanical treatment of Szilard's engine: Implications for the entropy of information

We present a quantum-mechanical analysis of Szilard's famous single-molecule engine, showing that it is analogous to the double-slit experiment. We further show that the energy derived from the engine's operation is provided by the act of observing the molecule's location. The engine can be operated with no increase in physical entropy, and the second law of thermodynamics does not compel us to relate physical entropy to informational entropy. We conclude that information per seis a subjective, idealized, concept separated from the physical realm. Physical entropy depends on physical objects and physical interactions, and any entropy change owing to observations is entirely a result of the entropy created in the physical apparatus by the process of observation.     

物理演示实验教学在高素质新型军事人才培养中的作用

培养高素质新型军事人才是国防科技大学的核心任务之一.物理演示实验以直观、形象地演示物理现象为课程特色,可有效提高学员对物理规律、物理本质的直观认识和深刻理解,并引起学员的深入思考,在教学实践中可促进学员科学素质、综合能力和创新能力的提高.     

Fundamentals of the nonholonomically covariant formulation of the general theory of relativity

The physical foundations of the nonholonomic formulation of general relativity are determined, and the role of the Fock-Ivanenko coefficients in setting up and developing the tetrad formalism in general relativity is discussed. The physical and geometrical meaning of the nonholonomic transformations used in general relativity is determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 55–60, December, 1974.     

Changes in the physical structures for new versions of the Degasperis-Procesi-Camassa-Holm model

The goal of this work is to develop new solutions for modified versions of Degasperis-Procesi and Camassa-Holm model (DP-CH). In earlier studies, it has been observed that the new modification caused a deformation in the physical structures of the standard DP-CH and changed it from peakon-type to bell-shaped type. Further modifications of the modified DP-CH is presented, and a new deformation is reported for the new version as a change from bell-shaped type to periodic-wave type. The Kudryashov-expansion method and the sech-csch function method are used to support our findings. We concluded in this study that a change in the convection term for a physical model results in a change in its physical structure.     

Equivalence of the degrees of freedom in a unified gravitational theory

A discussion of the nouniqueness of physical laws and their invariance groups is illustrated by the construction of a physical theory (presented earlier) in which the law of motion of structureless and spinning particles is unified in the geometry of the manifold of the de Sitter groupSO(3,2). The theory has the structure of a non-Abelian Kaluza-Klein theory with very special properties resulting from the topology and noncompactness of the groups. The physical interpretation of the field equation is discussed. The physical requirement of equivalence of the interaction of spinning and orbiting systems, generally unconsidered in related theories, is here taken into account by the structure of the theory. The possibility of deviations from predictions of general relativity exists. Generalizations of the theoretical structure to higher dimensional groups are outlined and open the possibility for observations.     

高中物理实验思维能力结构模型分析及培养实践研究

物理实验思维能力的培养是物理实验能力培养的核心问题,而思维品质的培养又是实验思维能力培养的关键.通过多年的教学实践和相关的理论学习,笔者提出了物理实验思维能力结构模型,并探讨其在物理实验思维能力培养实践中的运用.     

留数定理在拓扑相变中的应用

留数定理是高校物理专业必修课程数学物理方法中的一个重要定理.传统教学中关于该定理的讲授着重于数学公式的推导和数学思想的传达,而对于其在具体物理问题上的应用鲜有涉及.本文以一维Su-Schrieffer-Heeger模型的拓扑相变问题为例,阐明了如何利用留数定理解析得到二阶位移量的表达式并用该物理量表征拓扑相变.在讲授留数定理的教学过程中引入具体物理问题的分析实例,可以使学生更深刻地理解数学定理中的物理内涵.     

On the physical interpretation of the central-symmetric gravitational-field singularities

It is shown that the existence of singularity in the centrally symmetric gravitational field, which is interpreted as a surface with unusual physical properties, follows from equations for the action and the energy of a test particle not using Einstein equations and their solutions. A black hole is treated as a physical model of the singularity in question. The results are compared with the usual interpretation of the singularity in Schwarzschild solutions to Einstein equations.     

Physical ambiguity of the notion of the solubility limit by the example of its determination using the formation of graphene on the surface in the Re-C system

Results obtained during the determination of the solubility limit of carbon in metal based on the detection of the time instant of the nucleation of the new phase, graphene, have been considered. Graphene is easily detected by the surface-sensitive methods of thermionic emission and electron Auger spectroscopy. It has been shown that the nucleation of the first graphene islands and the formation of the graphene monolayer covering the whole surface and even the multilayer graphite film on it can be used as the time instant of the phase transition depending on the sensitivity of the method. The solubility limits differ by many times depending on the determination method. This indicates the physical ambiguity of this physical characteristic of the double systems analogous in physical meaning to the pressure of the saturated vapor for the phase transitions in the one-component systems.     

线宽增强因子对光反馈半导体激光器混沌信号生成随机数性能的影响

基于光反馈半导体激光器产生的宽带混沌信号作为物理熵源生成物理随机数已得到广泛研究.线宽增强因子的存在会导致半导体激光器出现大量不稳定动态特性,因此,本文着重研究半导体激光器的线宽增强因子对生成随机数性能的影响.数值仿真结果表明:随着线宽增强因子的增加,光反馈半导体激光器输出混沌信号的延时峰值逐渐减小、最大李雅普诺夫指数逐渐增大.基于不同线宽增强因子下产生的混沌信号提取随机数,并利用NIST SP 800-22软件对生成随机数的性能进行测试.测试结果表明,选取线宽增强因子较大的半导体激光器产生混沌信号作为物理熵源易于生成性能良好的随机数.     

Dependence of physical interpretations on the choice of electromagnetic gauge

The principle of gauge invariance requires that the values of physically measurable quantities will be preserved upon changing the gauge in which electromagnetic quantities are expressed. It is emphasized here that physical interpretations do not depend only on laboratory measurables, but also upon other quantities that are altered by a gauge transformation. It is shown by a variety of simple examples that different gauges can lead to major changes in physical interpretations even though the electromagnetic fields are unaltered. The usual hypothesis that the radiation gauge (also known as the Coulomb gauge) is the “physical” gauge, in the sense that it meets the expectations of a laboratory interpretation, is supported by the various cases considered.     

Computational capacity of the universe

All physical systems register and process information. The laws of physics determine the amount of information that a physical system can register (number of bits) and the number of elementary logic operations that a system can perform (number of ops). The Universe is a physical system. The amount of information that the Universe can register and the number of elementary operations that it can have performed over its history are calculated. The Universe can have performed 10(120) ops on 10(90) bits ( 10(120) bits including gravitational degrees of freedom).     

Dissipativity and the spectral property of the collision operator

It has been shown by the Brussels School that there is a physical representation in which the evolution of the density matrix reveals the dissipative structure. In this article, we present a two-dimensional model of the collision operator with a singularity at the origin which characterizes a long-range force. The dissipativity and the approach to equilibrium in the physical representation are studied and it is shown that the second law may be established in spite of the failure of Boltzmann's kinetic equation.     

New theoretical approach concerning the physical phenomena in space and time,and the action principle

The unity of physical nature is advanced. A primordial continuum with geometric character is assumed to exist; its coordinates are the elements generating the physical magnitudes. The relation between these primordial coordinates and the physical magnitudes is established. Starting from the condition of minimum path in the primordial continuum, an explanation of the action principle is given. In sequence the equations for the four-dimensional space-time are obtained, and with some specializations the equation of gravity is derived.     

Physical implications of the cosmological constant

The contribution of the quantum vacuum to the energy-momentum stress tensor in Einstein's field equations is very large. The observed cosmos is not in agreement with such a large term; thus, we require the presence of a cosmological constant to cancel this term. We discuss why this constant cannot originate from a quantum field or the gravitational field. We propose that this constant is physical evidence of the structure of space. The physical structure of space gives space an existence independent of the existence of matter and radiation.     

高空核电磁脉冲模拟波形的双指数函数拟合法

 许多标准和公开出版物中都用双指数函数描述高空核电磁脉冲典型波形。通过数值方法，研究了双指数函数一项重要的性质。根据该性质，详细讨论了高空核电磁脉冲模拟波形数值拟合中，双指数函数特征参数与脉冲峰值、前沿、后沿以及半宽等物理参数的关系，从而提出一种简单有效的脉冲参数计算方法。通过IEC标准中规定的高空核电磁脉冲参数的估计与一个实测高空核电磁脉冲模拟波形的数值拟合，验证了该方法的有效性和可靠性。该方法能够适应多种峰值、前沿和半宽的高宽核电磁脉冲模拟波形的数值拟合。