Analysis of dynamic pull-in voltage and response time for a micro-electro-mechanical oscillator made of power-law materials

Nonlinear Dynamics - Analysis of dynamic pull-in voltage for a micro-electro-mechanical oscillator of platform type is performed. The lumped mass model for the actuated micro-cantilever beam made...     

Compounds of Acetamide and Its Analogs with Inorganic Acids: Synthesis and Properties

Quantum-chemical calculations with the MOPAC and HYPERCHEM programs and MNDO, AM1, and PM3 methods were used to identify the reaction center in the molecules of protonated acetamide and its analogs (alkylamides) and to determine the effect of their nature on reactivity. The results of calculations are supported by IR and UV data. The change in the reactivity of alkylamides during their reaction with inorganic acids is explained by the effect of the nature of a basic or acid partner.     

Energy dependence of optical-model parameters for the interaction of 6Li and 7Li Ions with 28Si nuclei at low energies

The results of a joint analysis of experimental data (angular distributions for scattering and total reaction cross sections) are presented for the case of the interaction of ^6,7Li ions with ²⁸Si nuclei at energies between 7.5 and 32 MeV. The respective calculations were performed on the basis of a deformed potential of the optical model by using the SPI-GENOA code. The energy dependences of the parameters of the macroscopic optical model and the total cross section for the (^6,7Li+²⁸Si) reactions were obtained over the energy interval from 7.5 to 32 MeV. The calculated angular distributions and total reaction cross sections are in good agreement with experimental data.     

Recombination luminescence of CaSO4:Tb3+ and CaSO4:Gd3+phosphors

A comparative study of the excitation of luminescence by VUV radiation as well as of thermally and photostimulated luminescence has been carried out for CaSO₄:Tb³⁺ and CaSO₄:Gd³⁺ phosphors, where Na⁺ or F⁻ ions are used for charge compensation. The distinction in hole processes for the phosphors with Na⁺ or F⁻ compensators is determined by the differing thermal stability of the holes localized at/near Tb³⁺Na⁺ and Gd³⁺Na⁺ (up to 100–160 K) or at/near Tb³⁺F⁻ V _Ca and Gd³⁺F⁻ V _Ca centers involving also a cation vacancy (up to 400–550 K). Tunnel luminescence in the pairs of localized electrons and holes nearby Tb³⁺ or Gd³⁺ has been detected. The mechanisms of electron-hole, hole-electron and tunnel recombination luminescence as well as a subsequent released energy transfer to RE³⁺ ions are considered.     

Laplace operator with δ-like potentials

We study the Laplace operator in a punctured domain in a Hilbert space. We obtain an analog of the Green formula and a class of self-adjoint extensions of the Laplacian. We also investigate a certain class of well-posed problems.     

On Volterra Three-Point Problems for the Sturm–Liouville Operator Related to Potential Symmetry

Mathematical Notes -     

Spectral problem for a triple differentiation operator with asymmetric weight

We study the spectrum of a class of two-point boundary value problems for an ordinary differential operator of triple differentiation with weight. We show that the spectrum of a problem with asymmetric weight and with periodic boundary conditions fills the entire complex plane. We present an example of a problem with asymmetric weight to which one cannot assign a given spectrum by changing only one of the boundary conditions.