Integrable fermion systems with fourth-order nonlinearity

One integrates the infinite-dimensional fermionic system governed by the superconductivity-like Hamiltonian. The theory of orthogonal polynomials is applied.     

The interior operation in aψ-density topology

We prove that for an arbitrary setA ? ? its interior in aψ-density topology equalsA ∩ φ^β(B), whereB is a measurable kernel ofA andβ is some countable ordinal. Moreover, eachβ, 1≤β<Ω, realizes the interior ofA for someA εS.     

An impact of multi-layered structures of modern optoelectronic devices on their thermal properties

Phonon scattering at layer boundaries reducing efficiency of heat extraction from volumes of modern multi-layered electronic devices is believed to be one of the most important obstacles to their further miniaturization. Therefore the main goal of this work is to examine theoretically thermal conductivities of thin semiconductor layers as a function of their thickness using, as a typical example, the GaAs layer between two AlAs or (AlGa)As layers. Applicability of various possible theoretical approaches to a heat transport in such a structure is discussed. However, theory of the nanoscale thermal transport has been found to be still at an immature stage. Nevertheless, following the phonon-radiative-transfer approach of Chen and Tien derived from the Boltzmann transport equation, the RT (=300 K) GaAs thermal conductivity has been found to be dramatically reduced from its bulk value of 44 W/mK, to only 1.05 W/mK for the 20-nm layer and even to 0.15 W/mK for 2-nm layer, which is in a general agreement with experimental results. However, this approach has happened to give distinctly incorrect results for relatively small composition changes of successive layers. Then reasonable values of effective thermal conductivities should be extracted from thermal conductivities determined experimentally for similar devices.     

An Almost Optimal Heuristic for Preemptive C max Scheduling of Dependent Tasks on Parallel Identical Machines

We consider the problem of scheduling preemptable, dependent tasks on parallel, identical machines to minimize the makespan. The computational complexity of this problem remains open if the number of machines is fixed and larger than 2. The aim of this paper is to compare two heuristic algorithms on a basis of a computational experiment. The solutions generated by the heuristics are compared with optimal solutions obtained by a branch-and-bound algorithm. Computational results show that the heuristic based on node ordering finds optimal schedules for 99.9% of instances with the maximum relative deviation from optimum of 4.8%.     

On the Cegrell classes

The Cegrell classes with zero boundary data are defined by certain decreasing approximating sequences of functions with different properties depending on the class in question. It is different for Cegrell classes which are given by a continuous function f, these classes are defined by an inequality. It is proved in this article that it is possible to define the Cegrell classes which are given by f in a similar manner as those classes with zero boundary data. An existence result for the Dirichlet problem for certain singular measures is proved. The article ends with three applications. Results connected to convergence in capacity, subextension of plurisubharmonic functions and integrability are proved.     

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Conductometric and DSC evidence for a high temperature phase transition in cobalt dibromide

A solid-state phase transition in cobalt dibromide at 647 K has been revealed by three different alternative current techniques. A small thermal effect of (181±18) J mol⁻¹ corresponding to the enthalpy of the transition has been determined by differential scanning calorimetry. The effect was observed on cooling and on heating as well.