Convective noise in molecular electronic transducers of diffusion type

Noise in molecular electronic transducers is experimentally studied in the absence of a working fluid integral flow in the channel. It is concluded that noise in these systems is of a convective nature at low frequencies. It is found that the noise reduced to the input noise signal is independent of differences in the design of the electrode unit of the transducer.     

Mechanism of energy relaxation in the system of Landau levels in quantum wells

The kinetics of intersubband relaxation of electron energy has been studied in the system of Landau levels lying below the optical phonon energy. The relaxation character in the considered system is revealed to differ qualitatively from that in the two-dimensional continuous subband of the quantum well. In particular, the mechanisms of electron subsystem thermalization and energy relaxation in the system of Landau levels are qualitatively different, and the electron subsystem relaxation time exceeds the thermalization time by several orders of magnitude.     

The stability and stabilization of the motion of non-conservative mechanical systems

Two stability problems are solved. In the first, the stability of mechanical systems, on which dissipative, gyroscopic, potential and positional non-conservative forces (systems of general form) act, is investigated. The stability is considered in the case when the potential energy has a maximum at equilibrium. The condition for asymptotic stability is obtained by constructing Lyapunov's function. In the second problem, the possibility of stabilizing a gyroscopic system with two degrees of freedom up to asymptotic stability using non-linear dissipative and positional non-conservative forces is investigated. Stability of the gyroscopic system is achieved by gyroscopic stabilization. The stability conditions are obtained in terms of the system parameters. Cases when the gyroscopic stabilization is disrupted by these non-linear forces are indicated.     

Partially neutral two-component systems

The results of a numerical simulation of the nonstationary processes in different charge-neutralization schemes of high-current electron beams and the results of a measurement of the beam parameters are presented. Most attention is paid to beams with a current higher than the limiting Alfven current.     

1-Benzoyl-2-aryl-3-arylmethyl-1,3-diazacyclanes — New products of the acylation of bis-azomethines

Conclusion The benzoylation of bis-azomethines derived from ethylenediamine and cis-1,3-diaminocyclohexane gives 1,3-dibenzoyl-1,3-diazacyclanes and 1-benzoyl-3-benzyl-1,3-diazacyclanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1132–1134, May, 1987.     

Analysis of shape memory alloys by neutron activation

The transition temperatures and ageing of shape memory alloys (SMA) depend on the chemical composition and purity. Methods for the deterrnination of trace impurities, doping and major elements in NiTi, CuZnAl and CuNiAl were developed using neutron activation analysis and -spectroscopy. For traces in Zn containing alloys, a chemical separation based on anion exchange resins was developed. Multielement analysis leads to detection limits ranging from 0.0001 to 1 g·g^–1. For major elements, optimization of the irradiation and spectrometry parameters enables standard deviation better than 0.5%.     

TDDFT studies of electronic structure and first hyperpolarizability of terta-nuclear cubane-like transition metal clusters

The TDDFT method is first applied in a series of tetra-nuclear transition metal clusters studies for nonlinear optical properties. The results indicate that the charge transfer inside the metal core [MCu3X4] (M=W, Mo; X=S, O, Cl, Se, Br) makes contribution to the optical nonlinearity. It is possible to enhance the hyperpolarizability by substituting the ligands of the clusters.     

On the Intermittency in Nuclear Fragmentations

A simple Monte Carlo simulation and even a partition method can be used to reproduce quite well the power law behavior between the factorial moment and the charge interval of fragment charge distributions from the multifragmentation of ¹⁹⁷Au nucleus bombarding emulsion at～1 GeV/nucleon. This indicates that the above power law seems not to be a unique precursor of the intermittent behavior in nuclear multifragmentations.     

NUCLEAR CHARGE DISPERSION OF FRAGMENTS IN HIGH ENERGY PROTON-NUCLEUS COLLISION

The charge dispersion of fragments in high energy p+Cu,Kr and Xe reactions are calculated by statistical model and Monte Carlo technique.The corresponding data are reproduced quite well.It is shown that the charge dispersions are all nearly gaussian.The mass dependence of the most probable fragment charge reflects the rest target memory effect.     

EQUATION OF STATE OF HOT NUCLEI BEFORE BREAK-UP

Following the method developed by the authors,recently,the equation of state of hot nuclei(²³⁸U in concrete) before break-up was investigated numerically.The isotherms are drawn in the plan of the general pressure P versus volume V_RT. They are similar to those of Van der Waals gas.The critical temperature of phase transition should correspond to the isotherm with one turning point only.It turns out that the data of mass yield distribution can be reproduced by many pairs of parameters T and V_RT (freeze-out temperature and freeze-out volume) varying in certain range.For each isotherm (each T),the data are always best reproduced by the value of V_RT located at the maximum general pressure within two phases coexistence region.