石榴石磁泡膜中3类硬磁畴的形成方法

研究石榴石磁泡膜中硬磁畴畴壁中垂直布洛赫线的稳定性可为研制布洛赫线存储器提供有益的帮助 .3类硬磁畴的形成是研究硬磁畴稳定性的前提 .本文综述了在石榴石磁泡膜上形成硬磁畴的 2类方法———“脉冲偏场法”和“低直流偏场法” .结合文献中的典型样品 ,对用“脉冲偏场法”和“低直流偏场法”形成 3类硬磁畴的过程进行了简单介绍 .     

面内场对三类硬磁畴的影响

采用直流偏场整形的方法,研究了面内场对石榴石磁泡薄膜中三类硬磁畴的影响.得到面内场作用下三类硬磁畴畴壁中垂直布洛赫线(VBL)是逐步解体的,而且三类硬磁畴具有相同的临界面内场范围［H¹_ip,H²_ip］,其中H¹_ip是硬磁畴中VBL开始丢失时的临界面内场,H²_ip是VBL完全丢失 关键词： 硬磁畴 整形 垂直布洛赫线     

Analysis of the domain wall structures of the three kinds of hard domains in garnet bubble films

It was found experimentally that dumbbell domains of the second kind produced at high temperature can convert to dumbbell domains of the first kind at low temperature. And the ordinary hard bubbles produced at low temperature can convert to dumbbell domains of the first kind at high temperature. So we conclude that the domain wall structures of the three kinds of hard domains are the same. We also observe that the equilibrium separation between two neighboring vertical-Bloch lines is widened with the increasing temperature when the hard domains collapse under the effect of bias field.     

Study of ferromagnetic bulk domains by neutron depolarization in three dimensions

The polarization change of a polarized neutron beam after transmission through a partly magnetized ferromagnetic material can be described by a (3×3) depolarization matrix. A theory has been developed to interpret this matrix in terms of well-known magnetic domain quantities such as the reduced mean magnetizationm, the mean domain size δ and the mean square direction cosines γ _x , γ _y and γ _z of the inner magnetization within the domains. In order to do this it was necessary to make some simplifying assumptions about ferromagnetic domain structures. The influences of these assumptions on the quantities derived have been discussed. Finally the theory has been applied to depolarization measurements in nickel foils with the magnetic field and mechanical stress as parameters.     

Properties of hard disc fluids by Baxter’s method

The radial distribution function and the equation of state for hard disc fluids have been calculated at various densities by solving Ornstein-Zernike equation using Baxter’s method.     

Behavior of vertical-Bloch-line chains of hard domains in garnet bubble films

As a main micromagnetic structure of domain walls in garnet bubble films, vertical-Bloch-line (VBL) chains play an important role in the characteristics of hard domains. In the 1970s, their study progressed rapidly during the period in which bubble devices were developed. When ultra-high-density Bloch line memory (BLM) was proposed in 1983, VBL chain behavior again attracted attention. This review will introduce the early achivements focusing primarily on the results of the last decade. A convenient method of forming VBL chains, a new classification scheme of hard domains and the unsolved “number effect” of VBLs will be discussed. Various behaviors of VBL chains under static compression, and in-plane magnetic fields will also be presented. Finally, the temperature stability of VBL chains will be reported.     

Formation of high pressure domains during plastic deformation

A synergetic macrostructure characterized by an inhomogeneous material and pressure density distribution is formed in plastically deformable specimens. The kinetics of macrostructure formation and partially the parameters are determined by two processes: autostimulated redistribution of the density and diffusion relaxation. Domains with elevated density perform primarily rotational motion.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 85–90, June, 1990.     

Formation of Condon domains as a phase transition

It is shown, for the first time, that approaching the Condon domain phase in temperature from above is accompanied by critical temperature growth of the susceptibility thereby indicating formation of Condon domains, which occurs as a phase transition. The study is based on a recent measurement of the temperature dependence of the susceptibility in silver in magnetic field of 25 T under conditions of the nonlinear de Haas-van Alphen effect. Experimental results for the positive and negative slopes of the magnetization in one de Haas-van Alphen period are in good agreement with results of the calculations presented here. The Curie-Weiss law for the susceptibility is derived for a needle-type specimen. The Curie constant is calculated.     

The volume internal to three intersecting hard spheres

The influence of hyperfine interaction on proton magnetic relaxation in dilute solutions of paramagnetic ions was investigated. Theoretical and experimental results were compared with the theory of Solomon and Bloembergen.     

Formation of an external source by a hard radiation pulse in an electrodynamic problem

A method is proposed for calculating an external source that forms when hard radiation is absorbed by matter. The relevant electrodynamic problem is solved by numerical modeling. It is shown that the current density vector can be localized in space and time.     

Exploring the latest Pantheon SN la dataset by using three kinds of statistics techniques

In this work,we explore the cosmological consequences of the latest Type Ia supernova (SN Ia)dataset,Pantheon,by adopting the wCDM model.The Pantheon dataset cu...     

Exploring the latest Pantheon SN Ia dataset by using three kinds of statistics techniques

In this work, we explore the cosmological consequences of the latest Type Ia supernova (SN Ia)dataset, Pantheon, by adopting the wCDM model. The Pantheon dataset currently contains the largest number of SN Ia samples, which contains 1048 supernovae on the redshift range0 z 2.3. Here we take into account three kinds of SN Ia statistics techniques, including:(1) magnitude statistics (MS), which is the traditional SN Ia statistics technique;(2) flux statistics(FS), which is based on the flux-averaging (FA) method; and (3) improved flux statistics (IFS),which combines the advantages of MS and FS. It should be mentioned that the IFS technique needs to scan the (zcut,Δz) parameters plane, where zcutandΔz are redshift cut-off and redshift interval of FA, respectively. The results are as follows.(1) Using the SN dataset only, the best FA recipe for IFS is (zcut,Δz)=(0.1, 0.08);(2) comparing to the old SN dataset, JLA, adopting the Pantheon dataset can reduce the 2σerror bars of equation of state w by 38%, 47%and 53%for MS, FS and IFS, respectively;(3) FS gives closer results to other observations, such as Baryon acoustic oscillations and cosmic microwave background;(4) compared with FS and IFS,MS more favors a Universe that will end in a ‘big rip’.     

三类大气基本波动的广义变分原理

半反推法是He为了寻求数学物理问题的变分原理而提出的, 可避免由拉氏乘子法引起的临界变分现象. 应用半反推法分别获得了动力气象中Rossby波、大气声波和重力外波等三类基本大气波动的广义变分原理, 并验证了它们的正确性.     

Formation of a microfiber bundle by interference of three noncoplanar beams

A systematic analysis of interference of three noncoplanar plane waves with identical frequency is provided. This analysis shows that a fiber bundle with spacing of the order of the wavelength, which one may conveniently control by changing the recording geometry, can be formed by this means. The relation between the incident light-wave vectors and the resultant pattern is analyzed. The concept of uniform contrast for an interference pattern is introduced, and the polarization optimization approach for each beam that ensures maximum uniform contrast for each beam is also given.     

High-temperature current conduction through three kinds of Schottky diodes

Fundamentals of the Schottky contacts and the high-temperature current conduction through three kinds of Schottky diodes are studied. N-Si Schottky diodes, GaN Schottky diodes and AlGaN/GaN Schottky diodes are investigated by I--V--T measurements ranging from 300 to 523~K. For these Schottky diodes, a rise in temperature is accompanied with an increase in barrier height and a reduction in ideality factor. Mechanisms are suggested, including thermionic emission, field emission, trap-assisted tunnelling and so on. The most remarkable finding in the present paper is that these three kinds of Schottky diodes are revealed to have different behaviours of high-temperature reverse currents. For the n-Si Schottky diode, a rise in temperature is accompanied by an increase in reverse current. The reverse current of the GaN Schottky diode decreases first and then increases with rising temperature. The AlGaN/GaN Schottky diode has a trend opposite to that of the GaN Schottky diode, and the dominant mechanisms are the effects of the piezoelectric polarization field and variation of two-dimensional electron gas charge density.     

A second order virtual node method for elliptic problems with interfaces and irregular domains in three dimensions

We present a numerical method for the variable coefficient Poisson equation in three-dimensional irregular domains and with interfacial discontinuities. The discretization embeds the domain and interface into a uniform Cartesian grid augmented with virtual degrees of freedom to provide accurate treatment of jump and boundary conditions. The matrix associated with the discretization is symmetric positive definite and equal to the standard 7-point finite difference Poisson stencil away from embedded interfaces and boundaries. Numerical evidence suggests second order accuracy in the L^∞-norm. Our approach improves the treatment of Dirichlet and jump constraints in the recent work of Bedrossian et al. [1] and introduces innovations necessary in three dimensions. Specifically, we construct new constraint-based Lagrange multiplier spaces that significantly improve the conditioning of the associated linear system of equations; we provide a method for cell-local polyhedral approximation to the zero isocontour surface of a level set needed for three-dimensional embedding; and we show that the new Lagrange multiplier spaces naturally lead to a class of easy-to-implement multigrid methods that achieve near optimal efficiency, as shown by numerical examples. For the specific case of a continuous Poisson coefficient in interface problems, we provide an expansive treatment of the construction of a particular solution that satisfies the value jump and flux jump constraints. As in [1], this is used in a discontinuity removal technique that yields the standard 7-point stencil across the interface and only requires a modification to the right-hand side of the linear system.     

三种节流元件湿气节流特性分析

湿气的节流机理和影响因素以及不同节流元件的节流特点是选择湿气生产过程中节流元件的理论依据。为提高湿气的生产效率,减少水合物生成,文中对Laval喷管、孔板和板阀进行结构设计,并利用FLUENT软件进行数值模拟和理论分析,通过研究不同工况下的湿气节流流场,得出不同影响因素对于节流压力场与温度场的影响。分析不同节流元件的节流特点,总结出不同元件适用的工况范围。