On the scale of “simultaneous” influence of several “hot” particles on the conditions of heat and mass transfer at ignition of liquid condensed substance

Processes of heat and mass transfer at igniting a film of a typical liquid burning substance—kerosene—by several small-size hot particles are investigated numerically. Characteristics of ignition by several particles are compared with similar parameters in a system of single hot particle-liquid fuel film-air. It is found out that a value of the interparticle distance affects characteristics of the process. Three possible regimes of ignition in a system of two hot particles-liquid fuel film-air, depending on the distance between the heat sources, are revealed.     

Ceramic bismuth titanate for high – temperature electro-acoustic transducers

The dimensionality of the photopyroelectric signal and the importance of radiation heat transfer mechanisms in a thermal-wave cavity (TWC) are closely investigated in the current study. Radiation components were added to the purely conduction model by linearizing the radiation heat transfer at the brass film-air boundary. A 3-D theoretical approach based on the Hankel integral was developed and implemented. Experimental results indicate that a 3-D model is necessary to describe the PPE signal, especially at low frequencies. Radiation is found to be the major contributor of the photopyroelectric (PPE) signal when high frequencies and large cavity lengths are used.     

Synthesis and properties control of fluorinated organic-inorganic hybrid films

Fluorinated organic-inorganic hybrid films were prepared by free-radical random copolymerization and sol-gel process through dodecafluoroheptyl methacrylate (DFMA), vinyltriethoxysilane (VTES), and tetramethoxysilane (TMOS). It was found that the prepared fluorinated organic-inorganic hybrid film was very hydrophobic and exhibits excellent water repellency. Hydrophobic fluorocarbon side chains were preferentially enriched to the outermost layer at the interface of coating film-air, and three layers probably exist in the coating films. The fluorinated hybrid films possessed fluorocarbon side chains orient toward the air originating from DFMA as the top layer, hydrocarbon backbone chain originating from vinyl polymerization as the middle layer, and silica network originating from the hydrolysis and condensation of siloxane as the bottom layer. It demonstrated that most of TMOS added might be arranged to the bottom layer of the fluorinated hybrid films, and had a slight impact on the enrichment of fluorocarbon side chains of the outermost layer. However, the useful properties of the fluorinated organic-inorganic hybrid films such as thickness and corrosion resistant can be significantly improved by the increase of TMOS content.     

Scattering characteristics of a beam mode in dielectric-slab optical waveguide

Scattering of the light beam propagating through a dielectric-slab optical waveguide occurs due to refractive index inhomogeneities of the thin film region and due to boundary irregularities of the filmsubstrate and the film-air interfaces. The quantity and direction of the scattered light are evaluated by means of a perturbation method together with the use of a stationary phase method, for a variety of correlation lengths and variances and the thin film thicknesses. The results show that for a slab waveguide of t/=10.0,t and being the thickness of thin film and the wavelength of light, the effect of refractive index inhomogeneities is pronounced in comparison with that of waveguide wall irregularities. In this case, therefore, the scattering pattern is determined mainly by the correlation length of refractive index inhomogeneities.     

Trees at an Interface

A lattice tree at an interface between two solvents of different quality is examined as a model of a branched polymer at an interface. Existence of the free energy is shown, and the existence of critical lines in its phase diagram is proven. In particular, there is a line of first order transitions separating a positive phase from a negative phase (the tree being predominantly on either side of the interface in these phases), and a curve of localization–delocalization transitions which separate the delocalized positive and negative phases from a phase where the tree is localized at the interface. This model is generalized to a branched copolymer which is examined in a certain averaged quenched ensemble. Existence of a thermodynamic limit is shown for this model, and it is also shown that the model is self-averaging. Lastly, a model of branched polymers interacting with one another through a membrane is considered. The existence of a limiting free energy is shown, and it is demonstrated that if the interaction is strong enough, then the two branched polymers will adsorb on one another.     

On the fluctuation enhanced conductivity of a superconductor: The correct evaluation of the Maki graph

According to Maki, a particular diagram—the Maki graph—gives a contribution to the fluctuation enhanced conductivity of a superconductor which is infinite in the case of a thin film. It is shown that this result is spurious and that it is due to a breakdown of the standard Green function impurity technique. A new method is developed which is strictly based on the Boltzmann equation. It is shown that the temperature dependent contribution of the Maki graph to the conductivity is negligibly small in a dirty metal.     

Focusing of an X-ray spherical wave by a uniaxially bent crystal: Johann scheme and logarithmic spiral

Focusing of a spherical wave in the well-known Johann scheme is considered theoretically. An analytical formula for the size of the crystal bent surface reflecting radiation in the Johann scheme is derived. The intensity distribution near the focus is found. The spherical aberration of the diffracted beam is analyzed. Back scattering is shown to minimize the aberration. Spectral characteristics of an Johann spectrometer are discussed. The focusing of a spherical wave by a crystal bent into a logarithmic spiral is considered. It is shown that the Johann scheme is a specific case of a logarithmic spiral.     

Poisson brackets and the Feynman problem

A derivation of a pair of Maxwell equations which is based on the concept of a Poisson structure on a manifold is given. The idea is geometric in character, and is extended to a generalized algebra. The special case of the dynamics for a particle in a Yang-Mills field is obtained as a consequence of the generalized case.     

Integrability of Characteristic Hamiltonian Systems on Simple Lie Groups with Standard Poisson Lie Structure

Phase space of a characteristic Hamiltonian system is a symplectic leaf of a factorizable Poisson Lie group. Its Hamiltonian is a restriction to the symplectic leaf of a function on the group which is invariant with respect to conjugations. It is shown in this paper that such a system is always integrable.     

Design of a Reflective Aspherical Surface of a Compact Beam-Shaping Device

A compact beam-shaping device with a reflective aspherical surface is proposed. The device converts a circular symmetric Gaussian beam from a laser into a uniform distribution on a target plane. The device consists of a laser, a reflective aspherical surface formed on the base plane inclined by 45° against the optical axis, and a spacer. The surface is designed for an optical device used as a transmitter of indoor wireless optical communication, which is one of the promising applications. The designed surface is obtained by approximation using polynomial. Beam shaping of a simulated surface and a uniform intensity distribution on the target plane is obtained. The intensity distribution generated by the surface is numerically simulated and evaluated if the surface is misaligned. It is clarified that the generated distribution is tolerable for the misalignment.     

Wigner function and the entanglement of a quantized Bessel-Gaussian vortex state of a quantized radiation field

A new kind of quantum non-Gaussian state with a vortex structure,termed a Bessel-Gaussian vortex state,is constructed,which is an eigenstate of the sum of squared annihilation operators a2+b2.The Wigner function of the quantum vortex state is derived and exhibits negativity which is an indication of nonclassicality.It is also found that a quantized vortex state is always in entanglement.And a scheme for generating such quantized vortex states is proposed.     

A Minimal Framework for Non-Commutative Quantum Mechanics

Deformation quantisation is applied to ordinary Quantum Mechanics by introducing the star product in a configuration space combining a Riemannian structure with a Poisson one. A Hilbert space compatible with such a configuration space is designed. The dynamics is expressed by a Hermitian Hamiltonian containing a scalar potential and a one-form potential. As a simple illustration, it is shown how a particular type of non-commutativity of the star product is interpretable as generating the Zeeman effect of ordinary Quantum Mechanics.     

A fluid generalization of membranes

In a certain sense a perfect fluid is a generalization of a point particle. This leads to the question as to what is the corresponding generalization for extended objects. Here the lagrangian formulation of a perfect fluid is much generalized by replacing the product of the co-moving vector which is a first fundamental form by higher dimensional first fundamental forms; this has as a particular example a fluid which is a classical generalization of a membrane; however there is as yet no indication of any relationship between their quantum theories.     

Enhancement of an Instability by Internal Feedbacks in a Plasma

The electron-ion instability is excited in counterstreaming ion beams and plasma system. The instability is a new type of standing oscillations whose wavelength is given by D/n, where D is the distance between boundaries and n is an integer. The amplitude is controlled by a difference between the velocities of the beams, which changes the phase of a feedback loop. The internal feedback is caused by a reflected wave and by a coupling between the boundaries. Temporal evolution of the instability is measured and is found to agree with numerical solutions of the Van der Pol equation including a feedback term. A measured growth rate is proportional to the square of the oscillation amplitude.     

Multiple-reflection effects in hadron-nucleus scattering: (I). Cluster expansion of the optical potential

A basic assumption underlying the high-energy hadron-nucleus optical potential is that no target nucleon is struck more than once. Although this condition is satisfied at high energy, such is not the case in the vicinity of medium-energy resonances, where the amplitude for the projectile to undergo multiple reflections between two target nucleons is quite large. As a remedy for this problem, the multiple-scattering series is rearranged such that the optical potential can be expressed as a cluster expansion. The lowest order optical potential is modified by a two-body cluster term, which is a sum of all possible reflections of the projectile between a pair of target nucleons. This term is evaluated for a model potential within the formalism of Foldy and Walecka: it is substantially smaller than the contribution of a single reflection, and its overall effect is small under certain additional restrictions. If the independent-pair picture of nuclei is valid, then the three-body cluster term may be small, and the lowest order Glauber optical potential can provide a self-consistent picture of hadron-nucleus interactions, even though a term-by-term expansion of the multiple-scattering series does not provide such assurance.     

The interaction between a disclination in a nematic liquid crystal and a rubbed surface

For the case of a rubbed surface with a finite anisotropic surface tension, a model is developed for the structure and energy of a surface disclination and of an edge disclination near the surface. It is found that there is an energy barrier against detaching a disclination from the surface, and also that there is a critical distance within which a disclination is attracted, and beyond which it is repelled, by the surface. These properties may provide a measurement of the anisotropy of the surface tension.     

Distribution corresponding to classical thermodynamics

A distribution corresponding to classical thermodynamics is constructed. The concept of degrees of freedom is generalized and a concept of temperature-dependent number of collective degrees of freedom is introduced. A relationship between the theory of numbers and mesoscopic physics is established. A geometric interpretation of spinodal as a curve of maximum entropy and as a catastrophe in a quasi-static Caratheodory process is given. A concept of local ideal gas is introduced. The phase transition of fluids to a dispersed system is determined. The distribution obtained is numerically compared with the distribution for a van der Waals gas in the Hougen-Watson diagram.     

Spontaneous formation of a plasma hole in a rotating magnetized plasma: a giant burgers vortex in a compressible fluid

Spontaneous formation of a cylindrical density cavity, or "plasma hole," has been observed in a rotating magnetized plasma. Density of the plasma hole is one-tenth of that of ambient plasma and is bounded by a steep transition layer of the order of several ion Larmor radii. The flow velocity field associated with the plasma hole is experimentally determined, exhibiting a monopole vortical structure. It is found that the vorticity distribution is localized near the center of the hole and is identified as a Burgers vortex. This is the first experimental observation of a Burgers vortex in a plasma.     

Hidden symmetry of hyperbolic monopole motion

Hyperbolic monopole motion is studied for well separated monopoles. It is shown that the motion of a hyperbolic monopole in the presence of one or more fixed monopoles is equivalent to geodesic motion on a particular submanifold of the full moduli space. The metric on this submanifold is found to be a generalisation of the multi-centre Taub-NUT metric introduced by LeBrun. The one centre case is analysed in detail as a special case of a class of systems admitting a conserved Runge–Lenz vector. The two centre problem is also considered. An integrable classical string motion is exhibited.