Highly Efficient Gyrotron with Multi-Stage Recuperation of Residual Electron Energy

Technical Physics - The results of complex modeling of physical processes in a gyrotron of moderate power in the 4-mm wavelength range have been presented. Methods for improving the quality of the...     

Energy Spectra of Electron Beams and the Possibility of Double-Stage Energy Recuperation in a Double-Beam Terahertz Gyrotron

Radiophysics and Quantum Electronics - We study theoretically the possibilities of double-stage energy recuperation in a double-beam terahertz gyrotron. Numerical modeling, which was performed for...     

Energy Transfer in Spectra of the d-Dimensional Past Grid Turbulence

Free decay theory of the homogeneous and isotropic developed turbulence isconsidered in the d-dimensional case. The basic quantities under our consideration are the kinetic energy spectrum E(k,t) and energy transfer spectrum T(k,t) as functions of wave number k and decay time t. Starting point for studying E and T represents their adaptation from the stationary model which predicts the Kolmogorov spectrum which is multiplicatively dependent on an unknown scaling function F. In order to study the spectra of decaying turbulence both parameters l and εɛ are supposed to be dependent on t. Formerly derived basic integro–differential equation for F (by Adzhemyan, et al., 1998) has been here solved numerically in the dimension interval d∈(2, 3) for two cases of the Saffman invariant and the Loitsyansky integral fixing an arbitrary theor parameter α (α ⩵ 2 and 4, correspondingly). The energy transfer spectrum T(k) has been analyzed for several dimensions d≤3 showing the presence of integration regions in the wavenumber space where an inverse energy cascade can occur. PACS numbers: 47.27.ef, 47.11.-j, 47.27.er     

A Counterexample to the Quantizability of Modules

Let a Poisson structure on a manifold M be given. If it vanishes at a point m, the evaluation at m defines a one dimensional representation of the Poisson algebra of functions on M. We show that this representation can, in general, not be quantized. Precisely, we give a counterexample for , such that: (i) The evaluation map at zero can not be quantized to a representation of the algebra of functions with product the Kontsevich product associated to the Poisson structure. (ii) For any formal Poisson structure extending the given one and still vanishing at zero up to second order in epsilon, (i) still holds. We do not know whether the second claim remains true if one allows the higher order terms in epsilon to attain nonzero values at zero.      

Optimal Configuration of Dispersion Compensation Modules with Installation Limits

Selecting a cost optimum subset of discrete-value dispersion compensation modules (DV-DCMs) subject to maximum module count from an available set of DV-DCMs is a NP-hard problem. We derive a novel dynamic programming algorithm with pseudo-polynomial time bound and show that DV-DCM cost re-scaling can improve the running time.     

Investigation of Concentrator Photovoltaic Modules with Cascade Solar Cells

Technical Physics - The measuring capabilities of a solar radiation simulator and computer simulation have been used in the study of concentrator photovoltaic modules with three-junction solar...     

Equation of State Grid with the Quark-Meson-Coupling Model

In this work, we present the preliminary results of an equation of state (EoS) grid for possible use in core-collapse supernova simulations. We treat uniform matter made of nucleons using the quark-meson coupling (QMC) model. We show a table with a variety of thermodynamic quantities, which covers the proton fraction range Y _p = 0?0.65 with the linear grid spacing ΔY _p = 0.01 (66 points) and the density range ρ _B = 10¹⁴ ? 10¹⁶g cm^?3 with the logarithmic grid spacing Δlog₁₀(ρ _B /[g cm^?3]) = 0.1 (21 points). This preliminary study is performed at zero temperature, and our results are compared with the widely used EoS already available in the literature.     

Energy deficiency of the electromagnetic-impulse pendulum with respect to the Biot-Savart-Lorentz force law

Summary This letter is intended as a clarification of several doubts cast by Moyssideset al. on the experimental technique and analysis of the electromagnetic impulse pendulum performed at MIT. These disputed points are discussed and the proposed Ampère’s force formula is shown to be able to account for the energy imbalance observed.     

Measurement of the Thermal Characteristics of Concentrator Photovoltaic Modules

Technical Physics - In this paper, a technique is proposed to study the thermal properties of concentrator photovoltaic modules indoor in darkened conditions. The technique combines the procedure...     

Generalized Twisted Modules Associated to General Automorphisms of a Vertex Operator Algebra

We introduce a notion of a strongly ${\mathbb{C}^{\times}}We introduce a notion of a strongly \mathbbC^×{\mathbb{C}^{\times}}-graded, or equivalently, \mathbbC/\mathbbZ{\mathbb{C}/\mathbb{Z}}-graded generalized g-twisted V-module associated to an automorphism g, not necessarily of finite order, of a vertex operator algebra. We also introduce a notion of a strongly \mathbbC{\mathbb{C}}-graded generalized g-twisted V-module if V admits an additional \mathbbC{\mathbb{C}}-grading compatible with g. Let V=\coprod_{n ? \mathbbZ}V_(n){V=\coprod_{n\in \mathbb{Z}}V_{(n)}} be a vertex operator algebra such that V₍₀₎=\mathbbC1{V_{(0)}=\mathbb{C}\mathbf{1}} and V _(n) = 0 for n < 0 and let u be an element of V of weight 1 such that L(1)u = 0. Then the exponential of 2p?{-1}  Res_x Y(u, x){2\pi \sqrt{-1}\; {\rm Res}_{x} Y(u, x)} is an automorphism g _u of V. In this case, a strongly \mathbbC{\mathbb{C}}-graded generalized g _u -twisted V-module is constructed from a strongly \mathbbC{\mathbb{C}}-graded generalized V-module with a compatible action of g _u by modifying the vertex operator map for the generalized V-module using the exponential of the negative-power part of the vertex operator Y(u, x). In particular, we give examples of such generalized twisted modules associated to the exponentials of some screening operators on certain vertex operator algebras related to the triplet W-algebras. An important feature is that we have to work with generalized (twisted) V-modules which are doubly graded by the group \mathbbC/\mathbbZ{\mathbb{C}/\mathbb{Z}} or \mathbbC{\mathbb{C}} and by generalized eigenspaces (not just eigenspaces) for L(0), and the twisted vertex operators in general involve the logarithm of the formal variable.     

Classification of Harish-Chandra Modules over the Higher Rank Virasoro Algebras

We classify the Harish-Chandra modules over the higher rank Virasoro and super-Virasoro algebras: It is proved that a Harish-Chandra module, i.e., an irreducible weight module with finite weight multiplicities, over a higher rank Virasoro or super-Virasoro algebra is either a module of the intermediate series, or a finitely-dense module. As an application, it is also proved that an indecomposable weight module with finite weight multiplicities over a generalized Witt algebra is either a uniformly bounded module (i.e., a module with weight multiplicities uniformly bounded) with all nonzero weights having the same multiplicity, or a finitely-dense module, as long as the generalized Witt algebra satisfies one minor condition.This work is supported by a NSF grant 10171064 of China and two grants ``Excellent Young Teacher Program' and ``Trans-Century Training Programme Foundation for the Talents' from Ministry of Education of China.     

Application of the SCVT Orientation Grid to the Simulation of CW EPR Powder Spectra

The orientation grid obtained using the spherical centroidal Voronoi tessellation (SCVT) method is assessed for the simulation of continuous-wave electron paramagnetic resonance (CW EPR) powder spectra. The SCVT spherical code presents less distorted Voronoi cells associated to the points of the grid compared to the regular Igloo, SOPHE and EasySpin grids and similar distortions of the cells to the irregular Repulsion grid. The degree of distribution of the SCVT cells’ areas is smaller than for SOPHE, but higher than for the Igloo and Repulsion grids. All compared spherical codes have nearly the same electrostatic potential energy. Simulated CW EPR powder spectra for rhombic systems of spin S = 1/2 are similar when using the energy minimization SCVT and Repulsion spherical codes and show less intense ripples than the spectra calculated with the SOPHE and Igloo grids, but more intense than those obtained using the EasySpin grid. The classical projection method and a new modified form involving the spectral intensities at the orientations of the grid have been tested for the attenuation of the simulation noise, for grids of relatively reduced size.     

Suboptimal Processing of Output Data from Measuring Modules of Discrete Dynamic Systems with Weighing the Filter Coefficients

A problem of filtering the state vector of a discrete linear stochastic dynamic system is considered for modular organization of a measuring complex. A suboptimal filtration algorithm is constructed which operates with arbitrary observation matrices of individual measuring modules.     

Construction of Perfect Crystals Conjecturally Corresponding to Kirillov-Reshetikhin Modules over Twisted Quantum Affine Algebras

Assuming the existence of the perfect crystal bases of Kirillov-Reshetikhin modules over simply-laced quantum affine algebras, we construct certain perfect crystals for twisted quantum affine algebras, and also provide compelling evidence that the constructed crystals are isomorphic to the conjectural crystal bases of Kirillov-Reshetikhin modules over twisted quantum affine algebras.     

Energy approach to determination of the instantaneous damage level

A kinetic equation similar to the Kachanov-Rabotnov equation is derived from the law of conservation of mass for the case of isotropic damage. The energy balance is used to estimate the initial level of damage (instantaneous damage). The notion of instantaneous damage is akin to the concept of instantaneous deformation, which arises immediately after a load has been applied to a specimen in creep or toughness-elasticity tests. Using instantaneous damage as the initial condition for the standard evolutionary equation of damage like the Kachanov-Rabotnov equation, one can construct a more correct creep rupture diagram of structural materials than those currently available.     

Energy approach to solving the noise reduction problem

A new approach to solving the problem of reducing the noise produced by vibrating elastic structures is proposed. It is based on minimizing the flow of acoustic energy between subsystems by means of local structural changes. The author describes the theoretical grounding of this approach and presents the results from experiments that prove its relatively high efficiency (12–15 dB). The approach is useful in cases that require noise reduction without increasing the mass of a structure.     

Energy Transfer from the Aminophthalate Dianion to Fluorescein

Energy transfer from the excited aminophthalate dianion species to fluorescein at pH 8.32 (Tris-HCl buffer) was studied. The excited aminophthalate dianion species was obtained either by excitation with UV radiation (330 nm), with fluorescence emission, or by the well-known chemical reaction luminol-hydrogen peroxide in an alkaline medium, with chemiluminescent emission, both with _max at 425 nm. The influence of Co²⁺ and Mg²⁺ on fluorescence and chemiluminescence (CL) was studied. It was found that at low concentrations (10^–7–10^–9 M), these ions do not modify the fluorescein fluorescence, however, the CL is strong affected. The effect of the concentration of these elements, which exert an influence on CL even at a high dilution (nanomolar concentration), was determined. In the case of Co²⁺ the prooxidant character is stronger than in the case of Mg²⁺, and therefore the CL enhancer effect is higher. Compared to the system without catalyst, their presence ensures stronger, prolonged, and stable light emission. The emission spectra, in the presence of fluorescein, show two bands with maxima at 425 and 520 nm, the second one being specific to fluorescein emission. The intensity of aminophthalate dianion luminescence is lower and the duration shorter in the presence of fluorescein. The influence of Co²⁺ and Mg²⁺ catalyst and fluorescein concentration on the energy transfer process was studied. The efficiency of the energy transfer process for these two situations (fluorescence and CL) was compared. An attempt was made to replace hydrogen peroxide with superoxide anion (solubilized by means of crown ether) and its effect upon the energy transfer process was observed.