悬浮杜瓦通过永磁轨道开断处的纵向力研究

为了探索悬浮杜瓦通过永磁轨道开断处的纵向力变化规律及影响因素, 建立高温超导磁浮系统的理论模型, 推导了纵向力表达式, 进一步搭建实验平台, 在不同通过速度、 场冷高度和工作高度条件下, 对悬浮杜瓦脱离与进入永磁轨道时受到的纵向力进行测试. 理论与实验结果表明: 悬浮杜瓦通过永磁轨道开断处时受到纵向力作用,完全脱离前与进入后为阻力, 完全脱离后与进入前为主动力; 在低速运行范围内, 通过速度对纵向力的影响不大;随着工作高度的降低, 纵向力增大; 随着场冷高度的升高, 纵向力增大. 以上研究为高温超导磁浮系统的切换与发射提供设计参考.     

Cyanide-bridged WVMnIII single-chain magnet based on an octacoordinate [W(CN)6(phen)]? anion

Reaction of unique [W(CN)6(phen)]- with a magnetically anisotropic Mn Schiff base yielded a WⅤ(5d)-MnⅢ(3d) bimetallic compound with a linear chain structure. The magnetic properties of the chain complex feature a ferrimagnetic behavior as well as slow magnetic relaxation typical for a single-chain magnet.     

人民币实际汇率失调程度的META方法分析

本文采用Meta方法,对当前有关人民币实际汇率失调程度的研究成果的差异性进行系统分析。首先通过对现有的研究文献进行筛选,确定效应量,进行异质性检验;其次进行Meta回归,以检验研究文献的结论产生差异的原因。分析结果显示,应用不同的变量对人民币均衡汇率水平的估计,会对实际汇率失调程度产生大小不等的和方向各异的影响。进而通过一定的统计技术论证了影响人民币均衡汇率水平的各变量的作用。     

The Solid State Packing of Difluorophenyl-Dithiadiazolyl Radicals

The solid state structures of a series of difluorophenyl dithiadiazolyl radicals are presented and the packing described in terms of S...F, S...S, F...F secondary interactions.     

Magnetic properties and thermodynamics of decorated Ising chain with pendants of arbitrary spin

The decorated Ising chain with pendants of arbitrary spin and the single-ion anisotropy is exactly solved by the transfer matrix method. The solutions reveal abundant novel properties than the conventional one-dimensional Ising model. It is compared with the experimental data of a necklace-like molecule-based magnet, that gives a qualitative consistency.     

ESR study of the molecular orientation and dynamics of stable organic radicals included in the 1‐D organic nanochannels of 2,4,6‐tris‐4‐(chlorophenoxy)‐1,3,5‐triazine

The molecular orientation and dynamics of the organic stable radicals such as 2,2,6,6‐tetramethyl‐1‐piperidinyl‐1‐oxyl (TEMPO) or 4‐hydroxy‐TEMPO (TEMPOL) included in the one‐dimensional (1‐D) organic nanochannels of 2,4,6‐tris‐4‐(chlorophenoxy)‐1,3,5‐triazine (CLPOT) were investigated by examining the inclusion compounds (ICs) diluted by the co‐inclusion of non‐radicals using ESR spectroscopy. Spectral simulation showed that the axial rotation of TEMPO or TEMPOL molecules is excited in the nanochannels with activation energies of 8 and 7 kJ mol^?1, respectively. The rotation axis was estimated to be tilted towards the principal x direction in the axis system of the g ‐tensor of the respective radicals. This is quite different from that for similar ICs in the nanochannels of tris(o‐phenylenedioxy)cyclotriphosphazene (TPP), in which the radicals are axially rotating around the principal axis y of the g‐tensor. The difference is attributed to the larger nanospace of the CLPOT nanochannels. Copyright © 2012 John Wiley & Sons, Ltd.     

5kJ高温超导环型储能磁体电磁优化设计

电磁优化设计在高温超导磁体的设计中占有至关重要的地位。文中应用MATLAB中的遗传算法工具箱并结合ANSYS有限元仿真计算,对高温超导储能磁体进行了电磁优化设计,给出了用AMSC公司生产的YBCO带材进行储能量为5kJ的环型磁体的电磁优化设计的结果,并对优化设计的结果进行了分析和总结。     

Magnetite and magnetite/silver core/shell nanoparticles with diluted magnet-like behavior

In the present work is reported the use of the biopolymer chitosan as template for the preparation of magnetite and magnetite/silver core/shell nanoparticles systems, following a two step procedure of magnetite nanoparticles in situ precipitation and subsequent silver ions reduction. The crystalline and morphological characteristics of both magnetite and magnetite/silver core/shell nanoparticles systems were analyzed by high resolution transmission electron microscopy (HRTEM) and nanobeam diffraction patterns (NBD). The results of these studies corroborate the core/shell morphology and the crystalline structure of the magnetite core and the silver shell. Moreover, magnetization temperature dependent, M(T), measurements show an unusual diluted magnetic behavior attributed to the dilution of the magnetic ordering in the magnetite and magnetite/silver core/shell nanoparticles systems.     

Correlation functions of the XX Heisenberg magnet and random walks of vicious walkers

We investigate a relation between random walks on a one-dimensional periodic lattice and correlation functions of the XX Heisenberg spin chain. Operator averages over the ferromagnetic state play the role of generating functions of the number of paths traveled by so-called vicious random walkers (vicious walkers annihilate each other if they arrive at the same lattice site). We show that the two-point correlation function of spins calculated over eigenstates of the XX magnet can be interpreted as the generating function of paths traveled by a single walker in a medium characterized by a variable number of vicious neighbors. We obtain answers for the number of paths traveled by the described walker from a fixed lattice site to a sufficiently remote site. We provide asymptotic estimates of the number of paths in the limit of a large number of steps. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 159, No. 2, pp. 179–193, May, 2009.