Baryon number transfer in hadron + nucleus and nucleus + nucleus collisions: a link between elementary and complex interactions

The baryon number transfer is studied in elementary and complex hadronic interactions at the CERN experiment NA49 at the SPS, at 158 AGeV beam energy (√s=17.2 GeV) A two-component picture is proposed, which builds up the net proton distribution from a target and a projectile component. Using pion beam, the projectile component is experimentally determined for p + p and p + A interactions. A similar stopping behaviour of the projectile component is found for p + A and A + A interactions. Based on these observations, the baryon transfer is assumed to provide a common scale of inelasticity in p + p, p + A and A + A interactions. A model-independent way is proposed to predict the pion multiplicity in A + A.     

Some general problems of fast electrons transport

A generalization is given of the segments method in the form of a multistep method with generalized time for computing the transport of fast particles. The integral equation for a flow with generalized time in the phase space of variables is written under the assumption that the flow cuts the generalized time surface at right angles. The Green's function for the differential flow operator is the kernel of the integral equation. It is also shown that such an integral equation which can be obtained from a nonstationary kinetic equation provides a uniform consistent algorithm for solving either nonstationary or stationary problems. Examples of Green's functions are given for an operator of differential flow of fast electrons.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 110–114, August, 1974.The author would like to express his thanks to A. A. Vorob'ev and B. A. Kononov for their encouragement, to A. P. Yalovets for discussing the work with him, and to A. M. Kol'chuzhkin for going through the text.     

高能激光束自动对准和稳定系统的结构设计

介绍了一种用于两个光学平台之间光轴自动对准和稳定光束的设计方案。以可绕ｘ,ｙ,ｚ三个方向转动的导光管为单元,组成导光臂连接两个光学平台,消除两个平台之间相对运动产生的光轴对接偏差。用压电陶瓷驱动的倾斜镜作光束稳定元件,消除光束自身的漂移和平台间高频振动产生的光轴偏差。     

改进的Herriott型光学长程池

用凹面反射镜和平面反射镜组成结构简单、光路易调的光多次反射装置,计算了这种光学系统的稳定性条件。考察实际入射光束的直径和发射角,给出了最大反射次数的求法。制成适用于钛宝石激光光声光谱仪的光56次通过的长程池。理论计算的反射光斑分布与实验观测一致。这个技术有利于提高光声光谱和吸收光谱的探测灵敏度。     

Creating planar electrode systems for biosensors

A planar topology for a nanoelectronic transducer based on glucose oxidase is designed for use in an enzymatic biosensor. Electromigration is used to create 5-nm gaps in Au nanowires. A method for the chemical modification of a silica surface with epoxysilane is developed and glucose oxidase is immobilized on the surface of a support by means of linking molecules. A technique for biochemical signal registration is developed. The eelectric response of the biosensor with glucose in a test solution and the dependence of this response on the glucose concentration are investigated.     

Separable states are more disordered globally than locally

A remarkable feature of quantum entanglement is that an entangled state of two parties, Alice ( A) and Bob ( B), may be more disordered locally than globally. That is, S(A)>S(A,B), where S(*) is the von Neumann entropy. It is known that satisfaction of this inequality implies that a state is nonseparable. In this paper we prove the stronger result that for separable states the vector of eigenvalues of the density matrix of system AB is majorized by the vector of eigenvalues of the density matrix of system A alone. This gives a strong sense in which a separable state is more disordered globally than locally and a new necessary condition for separability of bipartite states in arbitrary dimensions.     

钙离子调控微丝切割蛋白中A6亚基解折叠的单分子力谱研究

在生命活动中,金属离子扮演了非常重要的角色.微丝切割蛋白(adseverin)需要钙离子的活化才能行使其切割肌动蛋白微丝的功能.本文通过基于原子力显微镜的单分子力谱研究了微丝切割蛋白C端末的A6亚基在结合钙离子前后的力学解折叠机理.实验结果显示:在未结合钙离子时,A6的解折叠表现为两态过程;在结合钙离子后A6力学稳定性显著提高;同时,钙离子的结合使得A6解折叠过程中出现稳定的中间态.通过对中间态的链长的分析,我们推测了中间态对应着A6的N端部分解折叠.而这一部分的解折叠可以使得掩藏在该结构后的A5亚基中肌动蛋白微丝结合位点暴露,从而促使微丝切割蛋白执行功能.我们的实验结果为理解微丝切割蛋白的工作原理提供了新的实验证据.     

On the Joint Distribution of Observables

A general algebraic system M is considered with two binary operations. The family of all measurable functions with values in the unit interval is a motivating example. A state is a morphism from M to the unit interval, an observable is a morphism from the family of Borel sets to M. A joint distribution of two observables is constructed. It is applied for the construction of the sum of observables and for a representation of conditional probability.     

液舱横荡非结构网格高阶格式数值模拟

提出一种液舱横荡数值模拟的方法,将气液两相交界面视为物理间断,通过高阶精度离散格式捕捉间断.根据NVD(Normalized Variable Diagram)实现非结构化网格上高精度离散格式,建立固定网格上自由表面运动模拟方法.在开发的非结构网格有限体积法求解器GTEA(General Transport Equation Analyzer)基础上,实现上述方法.首先对经典的溃坝过程进行模拟,并与文献结果对比验证方法和程序的可信度.对二维矩形液舱在不同激振频率时的横荡进行数值计算,并与实验以及商业软件CFX计算结果进行比较.结果表明方法和软件可以模拟自由面的翻卷、破碎运动现象,对距自由面较深点处流体载荷的计算结果与实验值符合较好,与商业软件CFX相比,在相同计算网格下,算法可以更好的计算次峰值,验证方法正确可行.     

Self-consistent field theory of a helix traveling wave tubeamplifier

A self-consistent relativistic field theory of a helix traveling wave tube (TWT) is presented for a configuration in which a thin annular beam propagates through a sheath helix enclosed within a loss-free wall. A linear analysis of the interaction is carried out, subject to the boundary conditions imposed by the beam, helix, and wall. A detrimental dispersion equation is obtained which implicitly includes beam space-charge effects without recourse to a heuristic model of the space-charge field. The equation is valid for arbitrary azimuthal mode number and is solved numerically for the azimuthally symmetric case. The coupled-wave Pierce theory is recovered in the near-resonant limit. Numerical comparisons between the complete dispersion equation and the Pierce model are described. A discrepancy is found between the Pierce and the field theory even for low currents in the nominally ballistic regime, owing to the dielectric effect of the beam on the helix modes     

A new method of non-contact gauge block calibration using a fringe-counting technique: I. Theoretical basis

A new non-contact interference method for gauge block or length bar calibration is presented. A central interference fringe of polychromatic light is used for the determination of the end surface position of the measured artefact. Distances referring to these positions are measured using a fringe-counting technique, with a wavelength-stabilized laser interferometer. Absolute and comparative measurement methods are proposed. A new technique for central interference fringe detection and identification is discussed.     

Piston-type radiator in a soft screen in the pekeris waveguide

A model problem is considered for a radiator in the form of a circular disk with a given pressure jump at its surface. The radiator is inserted in a soft screen coinciding with the upper boundary of the Pekeris waveguide. A series expansion of the sound field in normal modes is obtained. A numerical analysis of the radiation impedance and its components that are responsible for the radiation into the waveguide and into the halfspace is carried out.     

Gelation as a rod-glass transition

A sol-gel transition of rod-like macromolecules in solution is viewed as a rod-glass transition, similar to the spin-glass transition in dilute magnetic systems. A molecular field theory for the order parameters is presented. Varying the disorder parameter an ordered nematic-like phase is found for zero disorder, exhibiting first order transition, while a rod-glass second order transition is found for maximal disorder. A remanent nematic-like order always accompanies the glass phase, unlike the case of magnetic spin-glass.     

Cosmological Models with Rotation

A stationary cosmological model with rotation is constructed for the Ozsvath–Schucking metric where perfect fluid which is not comoving with the system is a source of the gravitational field. A nonstationary cosmological model for the Bianchi metric of type IX is also developed. This is characterized by expansion, rotation and acceleration. A co-moving with the system anisotropic liquid is a source of the gravitational field in this model.     

回旋管输出窗热性质的研究

一、引 言 输出窗是回旋管的能量输出端口,它的特性直接影响到回旋管的性能和寿命。输出窗的设计包括电特性和热特性的研究。当输出功率增加时,热特性的研究变得非常重要以便寻求合理有效的冷却措施。 输出窗由波导和介质片(块)两部分组成。回旋管的输出波导是圆波导,介质一般做成     

Quantum fluctuations of spatial dissipative solitons in a nonlinear interferometer

A quantum Langevin equation is derived that makes it possible to study the radiation field in a large-aperture nonlinear interferometer excited by external classical radiation. This equation is linearized in the vicinity of the solution for a stationary soliton. A mathematical formalism for obtaining a spectral representation of the solution to the linearized problem is constructed. It is shown that, in general, the excitation spectrum of a soliton consists of three branches, two of which belong to a continuous spectrum, while the third branch is discrete. The spectral representation obtained makes it possible to rigorously define the operator of soliton coordinate fluctuations, since, as is shown in the study, the traditional definition of this operator leads to a divergence in the vicinity of the solution. A new type of dissipative soliton is found, which is a natural generalization of a stationary soliton and takes into account its motion. A relation is found between this soliton and the contribution to the solution for field fluctuations from the discrete spectrum expansion. The mean squares of fluctuations of the soliton coordinate and momentum are calculated. A range of parameters is determined where the momentum of the soliton can always be measured with a spread smaller than the standard quantum limit. This possibility is related to the occurrence of states squeezed with respect to the soliton momentum. A scheme is proposed for the experimental observation of these states.     

Correlation mechanism of negative differential resistance for tunneling through a molecule

A model for electron transport through a single molecule with two electronic states, one of which is strongly hybridized with contacts and the other is localized, has been investigated. A solution for this model in the limit of strong intramolecular Coulomb interaction is found. A mechanism of negative differential resistance caused by strong intramolecular correlations is revealed.     

皮秒条纹相机的标定

介绍了一种通过迈克耳孙干涉仪,产生已知延迟时间间隔的双脉冲光作为校正用的基准时间间隔,利用条纹相机对超短激光脉冲进行精确测量的方法。     

Effect of angular aberration using the example of the laser location of a spacecraft in a geosynchronous orbit

A mathematical model for the laser location of a spacecraft in a geosynchronized orbit is generated in a rotating reference system. A formula for calculating the angular aberration that appears when the noninertial reference system is considered is derived. The maximum and minimum values of angular aberration are calculated for when the laser station is at the Equator.