Study of the mechanism of the particle—substrate interaction in the case of the impact of a supersonic heterogeneous flow on a flat solid wall

The mechanism of the interaction between a particle and a flat substrate in the case of the inleakage of a supersonic heterogeneous flow to a solid wall is studied. The equation of energy balance in the area of particle impact on the substrate is considered. This makes it possible to calculate the weight-averaged temperatures of the heated particle segment and also the average temperature of the heated substrate segment in the contact area during the impact. This equation is an adequate mathematical model of the physical process of special-coating deposition on different metal surfaces, including the structural components of air- and spacecraft, by the gas-dynamic method at low temperatures.     

Measurement of Eccentricity of the Centre of Mass from the Geometric Centre of a Sphere

The eccentricity of the centre of mass from the geometric centre of a spherical attracting mass in determining the Newtonian gravitational constant G is tested by means of an electronic balance. The experimental result shows that the eccentricity of the sample is about 0.31 μm with uncertainty of 0.05μm. Two density distribution models are discussed to estimate the uncertainty to G by the eccentricities of the attracting masses.     

Application of a recent solution of the Navier–Stokes equation to flow on the surface of a globe

We reduce an exact solution of the 3D Navier–Stokes equation (Muriel, 2011) [1] to two dimensions to model flow on the surface of a globe, producing the following results: (a) an analytic discovery of the time evolution of two streams, one each above and below the equator, (b) analytic speed-up of modeling bypassing iterative numerical simulation.     

Inverse problem of the scattering of a finite-length cylinder

Dealing with the direct problem of target scattering,the geomet-rical theory of diffraction and resonance scattering theory are used tostudy the scattering of an elastic cylinder,the results of which are appliedto solve the inverse problem.Using the geometrical theory of diffraction,the relations between the geometrical parameters of cylinder and thediffracted signals have been found,meanwhile the connexions between thephysical parameters of cylinder(i.e.the longitudinal velocity,transverse velocity and density of the material consisting of the cylinder)and the internal resonances of the cylinder have been shown by means ofthe resonance scattering theory.Therefore in the present artical an availa-ble method for solving the inverse scattering of cylinder is provided.     

Spectral density of the radiation excited by the field of a β particle in a diamondlike nanofilm

The generation of photon polaritons by a field of a moving ?? particle is numerically simulated. These polaritons are localized in a crystal nanofilm with a diamondlike structure. Expressions for the spectral density of the radiation excited by the field of a charged particle in a quasi-two-dimensional film are deduced.     

P2—a new measurement of the weak charge of the proton

After ten years of experience with parity-violating electron-proton-scattering, the preparatory work on a new high precision parity-violation experiment in Mainz has begun. Project P2 is bound to measure the weak charge of the proton to a relative uncertainty of 1.9 %, which corresponds to a relative uncertainty of 0.15 % for $\sin^2{\theta_{W}}$ . This can be achieved by measuring the parity-violating asymmetry in elastic electron-proton-scattering to a relative precision of 1.7 % at E _beam~200 MeV and Q ²~0.005 GeV². In this proceeding, we will discuss the achievable precision within project P2 as well as the experimental concept and present first results of studies involving Monte Carlo methods.     

Is there a spatial correlation in the distribution of adsorbed atoms in the cages of a zeolite?

Monte Carlo simulations of the cage-to-cage jumps of Xe atoms in a crystalline zeolite using the experimentally observed molecular rate constants for cage-to-cage jumps were carried out to determine if there is a systematic spatial correlation of the distributions of Xe atoms among the cages at equilibrium. The neighbours of cages having an Xe occupancy that is less than the average occupancy are found to have distributions that are skewed toward higher occupancy compared with the overall distribution. On the other hand, the neighbours of cages having an Xe occupancy that is greater than the average occupancy are found to have distributions that are skewed toward lower occupancy than the overall distribution.     

Anomalies of the electrical properties and the stability of the double layer at a metal-electrolyte boundary. Characteristics of the capacitance of a double layer with relaxing “plates∝

An electromechanical model of the electric double layer, whose plates are displaced on charging, is proposed; it is shown for the example of this model that the differential capacitance can diverge and become negative. The reasons why these anomalies were not predicted in the well-known models of the double layer are examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 9–15, November 1987.     

Comparison of the Radon–Nikodym Method with a Multistage Relaxation Model in the Analysis of the Fluorescence Dynamics of a Cold Atomic Ensemble

Optics and Spectroscopy - The fluorescence of cold atoms, cooled to ultra-low temperatures and excited by pulsed laser radiation, is calculated. The fluorescence of cold atoms is calculated based...     

Determination of the Local Parameters of a Cascade‐Arc Plasma by the Profiles of the Lines in the Radiation Spectrum

The transverse distribution of the plasma temperature in the positive column of a d.c. cascade arc in argon at atmospheric pressure has been measured. The measurements have been carried out by the conventional method involving the determination of the emissivity of plasma as well as directly from the radiation spectrum of the arc without recourse to the Abelian inversion. A theoretical and model justification of the applicability of the second method is given. The results of the determination of the temperature profile in the observation direction by the width and shift of the ArI 425.9nm line selected for the diagnostics are presented. An analysis of the data obtained supports the possibility of determining the temperature of an inhomogeneous, optically thin plasma from the profiles of lines in the emission spectrum.     

Visualization of the sound scattering by a cylinder

The schlieren method is applied to visualizing the sound scattering ofa cylinder immersed in the liquids.Images of the echoes,caused by normal andoblique incidence from a cylinder,are obtained for two kinds of liquids:(1)theliquid is composed of a transparent liquid;and(2)the liquid is composed of twonon-mixable transparent liquids.It is found experimentally that the echo canbe caused by the discontinaites in the shadow zone.This fact is utilized to dem-onstrate the locus of the helical surface wave creeping along the surface of thecylinder.For such cases the three-dimensional image can be described by thismethod and has not to use the system with special appliances and complexalgorithm.     

Effects of a rectangular aperture on the vectorial structure of a Gaussian beam in the far-field regime

With the help of the angular spectrum representation and the Gaussian function expansions of the hard-edge aperture function, the vectorial structure of a linearly polarized Gaussian beam (GB) diffracted by a rectangular aperture is analyzed in detail. It is found that the sizes of the energy flux density spots and the energy fluxes of the TE and TM terms depend on the aperture configuration and the polarization direction of the incident GB. The far fields may have smaller spots and larger energy fluxes for a GB diffracted by a rectangular aperture compared to that by a square aperture with the same beam intensity. And another potential application in information encoding and transmission for free-space communications is also proposed in addition to re-focusing to enhance the optical storage density. This encoding scheme has the benefit of easy implementation without modulating any properties of the light source.     

Measurement of the tensor analyzing power components in the coherent photoproduction of a π 0 meson on a deuteron

The components of the tensor analyzing powers, T ₂₀, T ₂₁, and T ₂₂, of the coherent photoproduction of a π₀ meson on a deuteron have been measured for photon energies of 250–450 MeV and pion emission angles of 90°–145°. The results are compared with the theoretical predictions.     

On a geometrical property of the Bäcklund transformation of the sine-Gordon equation

We show how a solution of the Bäcklund transformation equations for the sine-Gordon equation determines an explicit isometry from the underlying surface to the upper half plane. We then use the action on the upper half to find explicitly the general solution of the equations.     

Reduce of the Linewidth of a Diode Laser by Locking to a High-Finesse Fabry-Perot Cavity

We report frequency locking of a commercial 657nm diode laser to a high finesse Fabry-Perot cavity by the_ Pound-Drever-Hall method. The laser linewidth relative to the cavity is estimated to be about 6 kHz.     

In search of the ‘impenetrable’ volume of a molecule in a noncovalent complex

ABSTRACT

We propose to characterise the “impenetrable” volumes of molecules A and B in a complex A---B by finding that contour of its electronic density that separates the molecular surfaces of A and B but leaves them almost touching. The volume of the complex within that contour is always less than within the 0.001 au contour. The percent difference measures the interpenetration of the two molecules at equilibrium, and is found to directly correlate with the binding energy of the complex. We interpret the volume of each molecule that is enclosed by the almost-touching contour as that molecule's impenetrable volume relative to its particular partner. The percents by which the molecules' relative impenetrable volumes differ from their 0.001 au volumes in the free states also correlate with the strengths of the interactions. This allows the “absolute” impenetrable volume of any molecule to be estimated as ～25% of its 0.001 au volume in the free state. However this absolute impenetrable volume is only approached by the molecule in a relatively strong interaction.     

On the Stability of a Class of Modified Gravitational Models

Motivated by the dark energy issue, a minisuperspace approach to the stability for modified gravitational models in a four dimensional cosmological setting is investigated. Specifically, after revisiting the f(R) case, R being the Ricci curvature, we present a stability condition around a de Sitter solution valid for modified gravitational models of generalized type F(R,G,Q), G and Q being the Gauss-Bonnet and quadratic Riemann invariants respectively. A generalization to higher order invariants is presented.     

Development of the physical principles of the design and implementation of a 500–700 GHz spectrometer with a superconducting integrated receiver

A spectrometer based on the effect of freely decaying polarization in the frequency range 500–700 GHz has been designed. Radiation sources are harmonics from a quantum semiconductor superlattice frequency multiplier. The receiving system of this spectrometer is constructed using a superconducting integrated receiver based on a superconductor-insulator-superconductor mixer and a flux-flow oscillator operating as a heterodyne oscillator. The spectrometer has been used to measure absorption lines of NH₃ in a sample of expired air (572 GHz).