Direct Writing Micropatterns with a Resolution up to 1 µm

Solution processes have been widely used to fabricate micropatterned surfaces for its mild operation conditions. However, current approaches suffer from limitations of either low resolution or high cost. Here, a facile approach is proposed for direct writing micropatterns with a resolution up to ≈ 1 µm using a unit of triple conical fibers with the side‐by‐side parallel arrangement. With this unit, the resolution of the micropatterns can be mainly controlled by the single central conical fiber, with one side of the fiber facilitating continuous and steady liquid transfer onto the substrate and the other side mechanically supporting the whole unit. Particularly, the unit enables tunable dimension of the micropatterns within a rather large scale from ≈ 1 µm to ≈ 1.3 mm by varying the writing parameters (speed, height, and angle). Moreover, the unit is applicable for direct patterning various liquids, even into microline arrays, with a high resolution. It enables direct writing conductive microline with a width of ≈ 1 µm in a centimeter length scale, which can be used for constructing microcircuits. It is envisioned that the result offers a new perspective for preparing high‐resolution micropatterns using solution processes.     

Images of a First‐Order Spin‐Reorientation Phase Transition in a Metallic Kagome Ferromagnet

First‐order phase transitions, where one phase replaces another by virtue of a simple crossing of free energies, are best known between solids, liquids, and vapors, but they also occur in a wide range of other contexts, including even elemental magnets. The key challenges are to establish whether a phase transition is indeed first order, and then to determine how the new phase emerges because this will determine thermodynamic and electronic properties. Here it is shown that both challenges are met for the spin reorientation transition in the topological metallic ferromagnet Fe₃Sn₂. The magnetometry and variable temperature magnetic force microscopy experiments reveal that, analogous to the liquid–gas transition in the temperature–pressure plane, this transition is centered on a first‐order line terminating in a critical end point in the field‐temperature plane. The nucleation and growth associated with the transition is directly imaged, indicating that the new phase emerges at the most convoluted magnetic domain walls for the high temperature phase and then moves to self‐organize at the domain centers of the high temperature phase. The dense domain patterns and phase coexistence imply a complex inhomogenous electronic structure, which can yield anomalous contributions to the electrical conductivity.     

基于FUJITSU公司MB86H20B平台的机顶盒软件结构设计与实现

机顶盒包括硬件系统和软件系统,数字电视节目的接收、呈现以及其他业务的实现、都需要软件系统来完成。本文主要介绍了机顶盒的软件系统模型,以及基于FUJITSU MB86H20B平台机顶盒的软件系统结构的总体设计。     

两个自旋为1/2粒子在纠缠量子系统中的Berry几何相位

研究了两个自旋为1/2的粒子在自旋相互作用情况下的Berry几何相位纠缠依赖,分别计算了两个自旋为1/2的纠缠粒子之间在存在自旋相互作用和无相互作用下的Berry几何相位,并得到在纠缠消失时几何相位的计算表达式.而且我们还讨论了两个粒子中只有一个粒子受到外磁场作用时的几何相位.结果发现其几何相位并不等于单个粒子在受到外磁场作用时的几何相位,而是与影响自旋纠缠强度作用的 有关,同时还得到了几何相位依赖于纠缠的的普遍公式.     

纳米Fe-In2O3颗粒膜的低温磁效应

采用射频溅射法制备了纳米Fe—In2O3颗粒膜，研究了颗粒膜在低温下的两种特殊磁效应——巨磁电阻效应和磁性弛豫效应。磁电阻测量结果表明，当Fe体积分数为35％时，颗粒膜样品的室温磁电阻变化率(△ρ/ρ0)为4．5％，而在温度T=2K时，∑ρ／ρ0达85％。根据颗粒膜低场磁化率-温度(x-T)关系证实，在一定温度下，颗粒膜中纳米Fe颗粒表现出磁性弛豫效应，当截止温度TB=50K时，颗粒膜的磁特性由超顺磁性转变为铁磁性；在截止温度以上，其饱和磁化强度与温度关系符合Bloch的T^3/2定律。     

RS-422/485隔离技术及应用讨论

概述了RS-422/485串行总线技术标准,并对工业应用现场中可能出现的影响总线误判的因素进行了分析,对目前使用的隔离技术进行对比和总结。最后给出了实际的解决方案。     

溶胶-凝胶法制备钴铁氧体薄膜及温度对其磁性的影响

采用溶胶-凝胶法在单晶硅上制备了钴铁氧体薄膜。在不同温度下对样品进行了退火处理,通过X射线衍射仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）和振动样品磁强计（VSM）等分析了样品的物相组成、晶粒大小、表面形貌、样品厚度及不同温度下的磁性能。结果表明：制备出的CoFe2O4薄膜为尖晶石结构,表面比较致密,平均晶粒尺寸20～50 nm。在173～400 K范围内,随着温度的升高,钴铁氧体薄膜的矫顽磁场逐步减小,而磁矩是先增加后减少,并对产生的原因进行了分析。     

Structural, electrical and magnetic characterizations of Ni/Cu/p-Si Schottky diodes prepared by liquid phase epitaxy

In this paper, we have investigated the structural, electrical and magnetic characterizations of Ni/Cu/p-Si Schottky diode prepared by liquid phase epitaxy (LPE). Current density-voltage (J-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) measurements were performed to determine the conduction mechanisms as well as extracting the important diode parameters. Rectifying properties were obtained, which definitely of the Schottky diode type. At low voltages, (0 < V ? 0.4 V), current density in the forward direction was found to obey the diode equation, while for higher voltages, (0.5 < V ? 1.5 V), conduction was dominated by a space-charge-limited conduction (SCLC) mechanism. Analysis of the experimental data under reverse bias suggests a transition from electrode-limited to a bulk-limited conduction process for lower and higher applied voltages, respectively. Diode parameters such as, the built-in potential, V_b, the carrier concentration, N, the width of the depletion layer, W, of the Ni/Cu/p-Si Schottky diode were obtained from the C-V measurements at high frequency (1 MHz). The capacitance-frequency measurements showed that the values of capacitance were highly frequency dependent at low frequency region but independent at high frequencies. The Ni/Cu/p-Si Schottky diode showed magnetic properties due to the effect of Ni in the heterostructure.     

Techniques and Apparatus for Measuring Rotational Core Losses of Soft Magnetic Materials

In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.     

基于磁耦合共振传输技术的手机无线充电系统设计与研究

在社会经济与科技飞速进步的背景下,手机已经成为人们日常生活、工作中不可或缺的重要工具.无线充电系统能够较好地提升电能转化的效率,实现更加高效便捷的充电模式,应用磁耦合技术较好的摆脱充电线和充电接口的限制影响.文章系统性地介绍了磁耦合共振的工作原理和基本模型,结合手机无线充电的优势和现状,详细分析了该技术在充电系统中的设...