The Effect of Irradiation with Si+ Ions on Resistive Switching in Memristive Structures Based on Yttria-Stabilized Zirconia

Technical Physics Letters - We have studied the resistive switching in memristive structures based on 40-nm-thick yttria-stabilized zirconia (YSZ) films exposed to 6-keV Si+ ion irradiation to a...     

A method and setup for studying the energy dependence of delayed neutron characteristics in nuclear fission induced by neutrons from the T(p, n), D(d, n), and T(d, n) reactions

A method and a setup based on this method are described, with which it has for the first time become possible to measure the energy dependence of the absolute total and relative yields of delayed neutrons and the half-fives of their precursors from neutron-induced fission of heavy nuclei in the course of one experiment. T(p, n)³He, D(d, n)³He, and T(d, n)⁴He nuclear reactions induced by high-energy charged-particle beams from the KΓ-2.5 electrostatic accelerator at the Institute of Physics and Power Engineering are used as sources of monoenergetic neutrons. The measured total delayed neutron yields from neutron-induced fission of ²³³U and ²³⁹Pu nuclei in the energy range of 0.37–4.7 MeV, as well as the relative yields of delayed neutrons and the half-lives of their precursors from neutron-induced fission of ²³⁹Pu in the range of 15.8–17.9 MeV, are presented as an illustration of the method. The uncertainties of the data obtained by means of this method are shown to be significantly lower than the uncertainties of similar data measured using other techniques.     

Multiphase magnetic state of Ca1 ? x La x MnO3 ? δ single crystals ( x = 0.03, 0.05, 0.07) containing oxygen vacancies

Magnetic properties (magnetization, dynamic and static susceptibility) and transport properties (resistance and magnetoresistance) have been studied in a temperature range of 2–600 K in magnetic fields to 90 kOe for single crystals of Ca_{1 − x} La _x MnO_{3 − δ} with a weak electron doping (x ≤ 0.07) grown in argon and oxygen atmospheres. The magnetic state of Ca_{1 − x} La _x MnO_{3 − δ} single crystals is multiphase. Below T = T _N(G) ∼ 110 K, in all the crystals there coexists an AFM G phase with an FM contribution and an AFM C phase. In crystals with x = 0.07, a transition from the paramagnetic phase into the AFM C phase occurs in part of their volume below T ∼ 130–150 K. In crystals with x = 0.05 annealed in oxygen, an anomaly of paramagnetic susceptibility is observed near T ^* ∼ 270 K, which is related to the formation of FM clusters near defects. At x = 0.05 and 0.07, AFM correlations are retained in the paramagnetic state (to 600 K). The differences in the magnetic and transport properties of single crystals grown in argon and oxygen are explained by the various content of oxygen vacancies and by their possible ordering. Original Russian Text ? N.N. Loshkareva, A.V. Korolev, T.I. Arbuzova, N.I. Solin, A.M. Balbashov, N.V. Kostromitina, 2007, published in Fizika Metallov i Metallovedenie, 2007, Vol. 103, No. 3, pp. 261–270.     

Controlled synthesis of random,block-random and gradient styrene,methyl methacrylate and acrylonitrile Terpolymers via Nitroxide-mediated free radical polymerization

Different types of the styrene ? methyl methacrylate ?acrylonitrile terpolymers were synthesized according to the recently proposed concept of the living nitroxide-mediated terpolymerization. Random azeotropic and gradient terpolymers were prepared using the living TEMPO-mediated polymerization. Block random terpolymer was obtained via the living terpolymerization initiated by macro-alkoxyamine polystyrene-SG1. In all systems, terpolymerization proceeds in the living manner even in the presence of TEMPO. Upon complete polymerization at high conversions of monomers, the molecular weight of terpolymers linearly increases with the monomer conversion. The resultant terpolymers were characterized by the methods of turbidimetric titration, GPC, DSC, and TGA, and their characteristics were compared with their non-living analogs synthesized by the conventional radical polymerization. The effect of the macromolecular structure on the thermal stability of the terpolymers was studied.     

Properties of metal–polymer coatings obtained via joint electrodeposition on a cathode of a polyelectrolyte and metals

Copper- and zinc–polymer coatings were obtained via joint electrodeposition on a cathode of a water-soluble amine-containing polymer electrolyte and metals. The process of their formation, composition, structure, morphology, and properties were examined. The obtained coatings were found to possess high hardness and strength compared to pure polymer coatings if they have good elasticity.     

Evaluating the performance of FFT library implementations on modern hybrid computing systems

The Journal of Supercomputing - Fast Fourier transform is widely used to solve numerous scientific and engineering problems. In particular, this transform is behind the software dealing with speech...     

On evolutionary algorithms,neural-network computations,and genetic programming. Mathematical problems

Some problems related to evolutionary and genetic algorithms, genetic programming, and neural-network computations on solving applied problems that are reduced to analysis of functions prescribed at permutations are roughly studied. Natural parallelism of these algorithms and possibility of their realization on modern computers are noted.     

Studying nanocrystalline superconducting Nb<Subscript>3</Subscript>Sn layers in Nb/Cu-Sn composites of various design using NMR and magnetic susceptibility methods

The paper presents the results of measurements of the temperature dependence of the shape of the NMR lines of ⁹³Nb and of the real part of the dynamic magnetic ac susceptibility χ′(T) for multifilamentary superconducting Nb₃Sn-based composites with various geometry of niobium filaments (ordinary cylindrical, paired cylindrical, and ringlike (tubular)) produced by the bronze technology. In all the composites studied, a superconducting (SC) transition was observed in diffusional Nb₃Sn layers at T _c ～ 17 K. Its width is ΔT _c ≈ 3 K and is independent of the composite design. The difference in the absolute value of χ′(T) in the composites of ordinary assembly and with paired filaments is less by a factor of 1.5 than that of a composite with ring filaments. In the experimental NMR spectra of ⁹³Nb, subspectra of different intensities have been distinguished, whose number is three in ordinary assemblies and in assemblies with paired filaments, and two in composites with ring filaments. Estimates of the intensities of each subspectrum in each experimental spectrum of the composites studied has been correlated with a definite diffusional layer of Nb₃Sn; thus, the number of grains of a corresponding layer in each composite has been estimated. In addition, it has been established that in the first two composites the shape of the NMR line of ⁹³Nb is asymmetric, which indicates the existence of an anisotropy of the Knight shift in Nb₃Sn layers in both the normal and superconducting states, whereas in the composite with ring filaments the line is symmetric and the Knight shift is isotropic. The magnitude of the anisotropic Knight shift in composites with isolated and paired cylindrical filaments is ⁹³ K _an ≈ 0.02%. The anisotropy in them appears to be due to the different character and magnitude of interaction of grains of the Nb₃Sn layers with the bronze matrix and the residual Nb, which leads to different shifts of the subspectrum frequencies and, correspondingly, to the shape asymmetry of the NMR line of ⁹³Nb. At the same time, in a composite with ring filaments the interaction of the Nb₃Sn layer with the bronze matrix occurs on both sides, is, apparently, of the same character and is compensated in magnitude. In this case, in the first two composites the tin distribution across the diffusional layers of Nb₃Sn is nonuniform and a significant deviation from the stoichiometric composition is observed.     

An automatic hydraulic charger

Summary Our hydraulic charger with independent control of the process of charging a borehole with explosive cartridges has a servo system which determines the duration of transportation of the cartridge along the guide and controls the charging operation. The water pressure is converted to velocity and automatic dosing is effected by a differential valve to correspond with a given duration of the charging process. To reduce the speed of the cartridge when it leaves the guide, the latter is fitted with a hydraulic damper which transmits a pulse to the “command unit” to switch off the feed of pressurized water. Skochinskii Institute of Mining, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 103–107, January–February, 1966.