Showing papers by "Moscow Institute of Physics and Technology published in 1995"
TL;DR: It was shown that competition between hydrogen-producing and hydrogen-utilising acidogenic bacteria for glucose causes a hydrogen partial pressure decrease at a decrease of feed flow rate.
112 citations
TL;DR: In this article, the problem of photon generation inside an ideal 3D cavity with resonantly vibrating walls is studied, and the possibility of creating from a vacuum up to 104 photons in a cavity with a Q-factor of about 3 × 1010 is predicted.
92 citations
TL;DR: Theoretical studies conducted by means of various methods are reviewed, predicting the existence of the atomic stabilisation effect as mentioned in this paper, the reduction in photoionisation probability with increasing field strength in a fixed radiation field.
Abstract: Physical phenomena arising in the photoionisation of an atom in a laser radiation field are considered. Theoretical studies conducted by means of various methods are reviewed, predicting the existence of the atomic stabilisation effect — the reduction in photoionisation probability with increasing field strength in a fixed radiation field. Various experiments designed to observe the effect are discussed.
32 citations
TL;DR: In this paper, the authors consider a manifold of dimension 2n, where the algebra of flat sections of the Weyl algebras bundle W with respect to an Abelian connection D on W is considered.
Abstract: Let Q: C ∞ (M)[[h]] → W D be a quantization map considered in the author’s papers [2, 3, 4]. Here M is a symplectic manifold of dimension 2n, W D the algebra of flat sections of the Weyl algebras bundle W with respect to an Abelian connection D on W. The coefficient bundle of W is supposed to be Hom(E,E) for some m-dimensional complex vector bundle E. The Abelian connection D depends thus on the symplectic connection ∂s on M and the connection ∂ E on E.
20 citations
TL;DR: In this article, a class of functional-differential equations of neutral type with coefficients that are functions taking values in the set of (in general, unbounded) operators in separable Hilbert space is considered.
Abstract: A class of functional-differential equations of neutral type with coefficients that are functions taking values in the set of (in general, unbounded) operators in separable Hilbert space is considered. For such equations results on the well-posed solubility of initial-boundary-value problems on the semiaxis in Sobolev weighted spaces are established.
19 citations
TL;DR: In this paper, the photon statistics in superpositions of coherent states |α| and |α ∗ ∗ 〉 named ''Schrodinger real and im cat states'' were studied.
17 citations
7 citations
TL;DR: In this paper, the transition probabilities between the Landau levels due to kicking are expressed in terms of the Jacobi polynomials whose arguments contain the reflection coefficient from a series of delta-walls.
Abstract: We discuss the explicit analytical solution for the motion of a charged quantum particle in a homogeneous magnetic field under the influence of a series of delta -kicks of a cyclotron frequency. Transition probabilities between the Landau levels due to kicking are expressed in terms of the Jacobi polynomials whose arguments contain the reflection coefficient from a series of delta -walls.
7 citations
TL;DR: In this paper, a review of various theoretical approaches developed during the last few years, especially analytical considerations, is presented, and some new semi-analytical expressions for ionization rates, energy and angular distributions of ejected electrons are also derived.
Abstract: The theoretical description of the ionization of an atom (ion) by external electromagnetic radiation up to now concerned two alternative situations; multiphoton ionization and tunneling ionization. For both cases the formulas describing the ionization probability when the intensity of the laser field is not too strong are well known. However, if the field is strong, then there exists a new channel; the so-called barrier-suppression (or above-barrier) ionization of the atom. How does this process occur? It is obvious that barrier-suppression ionization and sub-barrier tunneling ionization by low-frequency laser field transform smoothly into one another as the field strength F is varied near the value of the barrier-suppression field FBSI. This paper contains a review of various theoretical approaches developed during the last few years, especially analytical considerations. Some new semi-analytical expressions for ionization rates, energy and angular distributions of ejected electrons are also derived.
4 citations
TL;DR: This analysis shows that a considerable enhancement of the scattering intensity in the superconducting state that is observed experimentally can be caused by an extension of the number of intermediate electronic states near the Fermi surface that participate in the Raman process.
Abstract: We compare theoretically the intensity of the ${\mathit{B}}_{1\mathit{g}}$ phonon Raman scattering in ${\mathrm{YBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ above and below the superconducting transition temperature ${\mathit{T}}_{\mathit{c}}$. Our analysis shows that a considerable enhancement of the scattering intensity in the superconducting state that is observed experimentally can be caused by an extension of the number of intermediate electronic states near the Fermi surface that participate in the Raman process.
4 citations
TL;DR: In this paper, an experimental demonstration was made of the effectiveness of an electric discharge, in the form of a high-velocity ionisation wave, in pumping a coaxial nitrogen laser operating at pressures of 5-120 Torr.
Abstract: An experimental demonstration was made of the effectiveness of an electric discharge, in the form of a high-velocity ionisation wave, in pumping a coaxial nitrogen laser operating at pressures of 5–120 Torr. The specific input energy delivered by this nitrogen-exciting wave was up to 2.1 J cm-3 in a time of the order of 10 ns. Lasing action was observed at the wavelength 337.1 nm under superradiance conditions. The peak power of an output radiation pulse reached 100 kW and the half-maximum duration was 10 ns. The range of the nitrogen pressures with maximal energy deposition in the gas coincided with the range of the minimal amplitude attenuation of the ionisation wave moving along the discharge gap. The input energy, the velocity and attenuation of the high-speed ionisation wave, and the laser radiation intensity were determined as a function of the nitrogen pressure.
TL;DR: In this paper, the ion and energy compositions of an erosion plume formed by microsecond CO2 laser pulses incident on a graphite target were determined and the dynamics was studied.
Abstract: The ion and energy compositions were determined and the dynamics was studied of an erosion plume formed by microsecond CO2 laser pulses incident on a graphite target. The ionic emission lines were used to find the electron density and temperature of the plasma on the target surface. The temperature of the plasma source did not change throughout the line emission time (4 μs). At the plasma recombination stage the lines of the C II, C III, and C IV ions were accompanied by bands of the C2 molecule near the target surface and also near the surface of an substrate when a plasma flow interacted with it. Ways were found for controlling the plume expansion anisotropy and for producing plasma flows with controlled parameters by selection of the conditions during formation of a quasisteady erosion plasma flow.
TL;DR: In this paper, the hypothetic R-resonance production with 60 GeV mass at FNAL hadron collider has been considered and the crosssection of this production with the consequent decay R→γγ is obtained.
Abstract: The hypothetic R-resonance production (anomalous ≪llγγ≫ events at LEP) with 60 GeV mass at FNAL hadron collider has been considered. The crosssection of this R-resonance production with the consequent decay R→γγ is obtained. Various distributions of leptons and photons in the process pp→llR(→γγ)X are calculated.
01 Mar 1995
TL;DR: In this article, the authors developed a method of modifying the surface of ceramic Y-Ba-Cu by laser irradiation, which allowed them to obtain ceramic superconducting structures on the surface with Tc equals 88 +/- 1 K, (Delta) T equals 1.4 +/- 0.1 K, Ic >= 104 A/cm2.
Abstract: The authors of the report developed the method of modifying the surface of ceramic Y-Ba-Cu by laser irradiation. This method permits us to obtain ceramic superconducting structures on the surface with Tc equals 88 +/- 1 K, (Delta) T equals 1.4 +/- 0.1 K, Ic >= 104 A/cm2. Such structures are the films 5 - 10 micrometers thick on the ceramic Y- Ba-Cu which are in the non-superconducted state.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: In this article, the authors investigated axial and radial shock waves formed in argon during propagation of an optical detonation wave maintained by a CO2 laser pulse, and the experimental results are not be described by the standard self-similar law of motion of a cylindrical shock wave, but instead they agree well with the results of self-consistent two-dimensional numerical calculations.
Abstract: Experimental and theoretical investigations are reported of axial and radial shock waves formed in argon during propagation of an optical detonation wave maintained by a CO2 laser pulse. The experimental results are not be described by the standard self-similar law of motion of a cylindrical shock wave, but instead they agree well with the results of self-consistent two-dimensional numerical calculations. This is attributed to displacement of a hot gas along the beam axis out of the zone of absorption of laser radiation. The distance R travelled by the front of the resultant radial shock wave during a time interval t is described by the law R ∝ tα, where 0.55<α<0.65.
01 Jan 1995
TL;DR: In this article, Tirskiy et al. investigated the free movement of a slender body of revolution through a rising large-scale cloud of hot gas in the stratified atmosphere.
Abstract: The free movement of a blunt slender body of revolution through a rising large-scale cloud of hot gas in the stratified atmosphere is investigated. An effective numerical method to determine the trajectory of the body is proposed. The method is based on the simultaneous solution of the flow and ballistic problems. The flow problem is solved by a highly economical (with respect to computer resources) method, which is based on the expansion in a small parameter (the angle of attack) (Tirskiy et al. 1992, 1994), in conjunction with the method of global iterations (Tirskiy et al. 1992, 1994). The proposed method allows to determine the aerodynamic coefficients, trajectory, and orientation of the body with a high accuracy. In addition, it minimizes the computer time needed to attain this accuracy. By this method it is determined how a raising cloud of hot gas influences on the trajectory, space orientation, and stability of the body. It is shown that the body can overturn when it goes through a low density raising cloud.
01 Mar 1995
TL;DR: In this paper, the influence of residual gas on optical properties of the produced coatings was explained in the framework of a simple mechanical model, and it was shown that the band gap value of the diamond-like films deposited in this case is more than 20% greater than that of the films deposited at high vacuum.
Abstract: Diamond-like films were produced by laser ablation of glass-carbon target in the presence of residual gas (Ar) in a reaction chamber. It appears that the band gap value of the films deposited in this case is more than 20% greater than that of the films deposited at high vacuum. This influence of a gas on optical properties of the produced coatings was explained in the framework of a simple mechanical model.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
01 Jan 1995
TL;DR: In this article, a set-up conjugated with a dielectric section in which an electric discharge developed in the form of a breakdown ionization wave with sublight speed is presented.
Abstract: A description of a shock tube set-up conjugated with a dielectric section in which an electric discharge developed in the form of a breakdown ionization wave with sublight speed is presented. This set-up allows to investigate plane shock wave propagation in an uniform, highly excited plasma and the breakdown of the gas gap by the shock wave in a wide range of the gas parameters. All disturbances existing in previous investigations of shock wave propagation in plasma with plasma production by glow or/and radio-frequency discharge such as flowing of the plasma by the gas flow etc. are eliminated by this method.
01 Jan 1995
TL;DR: In this article, a critical review of shock tube techniques for measuring the heterogeneous recombination probability of atoms on space vehicle surfaces while modeling natural reentering conditions is presented, and results of the determination of the heterogenous recombination probabilities for various types of thermal protection systems of Space Shuttle-type vehicles are given and analyzed.
Abstract: A critical review of shock tube techniques for measuring the heterogeneous recombination probability of atoms on space vehicle surfaces while modeling natural re-entering conditions is presented. Results of the determination of the heterogeneous recombination probability for various types of thermal protection systems of Space Shuttle-type vehicles are given and analyzed.
01 Jan 1995
TL;DR: In this paper, a set-up based on an electromagnetic shock tube for producing dense beams of active atoms with velocities corresponding to 1−10 ev translational energy is described.
Abstract: A description is made of a set-up based on an electromagnetic shock tube for producing dense beams of active atoms with velocities corresponding 1–10 ev translational energy; some illustrative results are also presented. This set-up allows to carry out investigations of fast active atom interaction with solid surfaces, taking place at vehicle orbital flights, in “TOKAMAK” controlled thermonuclear fission plants, etc.
01 Jan 1995
TL;DR: In this article, the rate constant of the NF3 dissociation reaction in a helium mixture in the low pressure limit P < 1 atm was measured in a shock tube by a UV absorption method.
Abstract: The rate constant of the NF3 dissociation reaction in a helium mixture in the low-pressure limit P < 1 atm. was directly measured in a shock tube by a UV absorption method. The rate constant may be expressed as K = 1014.38±0.07 x exp {-[36600 ± 2100(cal/mol)]/RT}, cm3/mol.s in the temperature range T = 1050–1600 K. Levels of the NF3 stationary dissociation fraction were also measured as a function of the initial temperature of the mixture behind the reflected shock wave. It increases monotonically with temperature and reaches 50% of the value at 1600 K, which corresponds to high NF2 concentration up to 2 x 1017 cm-3. Rates of NF3 thermal decomposition in the temperature range 1950–2050 K and pressure range 1.2-4.2 atm were also measured. The bimolecular rate constant of the NF3 decomposition reaction depends strongly upon pressure. An empirical formula was obtained from the experimental data which correctly expresses the dependence of the measured rate constant of decomposition upon the temperature and pressure of the reacting mixture behind the shock wave.
01 Mar 1995
TL;DR: In this paper, a diamond-like film deposition using laser-initiated discharge of benzol vapor is described, and the investigation of the discharge parameters is carried out, and a dependence of these parameters on characteristics of laser radiation, electric field and vapor pressure is obtained.
Abstract: A new method of diamond-like film deposition using laser-initiated discharge of benzol vapor is described. The investigation of the discharge parameters was carried out. Dependence of these parameters on characteristics of laser radiation, electric field, and vapor pressure was obtained. It has been shown that this method allows us to produce the coatings with low optical absorption.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
01 Jan 1995
TL;DR: In this article, multidimensional numerical simulation was applied to study the physical processes during interactions of strong shock waves produced by spatially-distributed sources both between them and with an unhomogeneous medium.
Abstract: Multidimensional numerical simulation was applied to study the physical processes during interactions of strong shock waves produced by spatially-distributed sources both between them and with an unhomogeneous medium.
01 Jan 1995
TL;DR: In this article, an ENO algorithm on adaptive moving grids is proposed to simulate the hypersonic motion of a gas cloud after the explosion of a meteorite in the atmosphere of a planet.
Abstract: The hypersonic motion of a gas cloud after the explosion of a meteorite in the atmosphere of a planet is numerically simulated. The gas flow is characterized by strong shock waves corresponding to large Mach numbers, and also by fast changes in size and position of the perturbed region. To solve the cited problem efficiently a combined numerical algorithm is proposed. The algorithm is an ENO algorithm on adaptive moving grids. The application of ENO approximations enables flows with strong shocks to be calculated and the use of adaptive moving grids enables computer resources to be minimized in terms of time and storage. The algorithm proposed is of interest in itself. To our knowledge this work is the first one in which an ENO scheme is extended to two-dimensional moving grids.