含铂中间层二氧化铅阳极的制备及其性能

钛基二氧化铅阳极广泛应用于电解工业,但使用过程中会因钛基体的氧化和二氧化铅活性层内应力较大而失效.为解决这些问题,进行了含铂中间层二氧化铅阳极的研究.对钛基体预处理,在480℃下烧结制备铂中间层,然后电沉积二氧化铅活性层.通过SEM分析铂中间层和阳极活性层的表面形貌,XRD分析中间层的成分以及相结构,Tafel曲线分析二氧化铅阳极的电化学性能,加速寿命试验分析阳极的使用寿命.结果表明,含铂中间层二氧化铅的加速寿命大约是含α-PbO2中间层二氧化铅阳极的加速寿命的3倍.     

Wafer Bonding and Layer Splitting for Microsystems

In advanced microsystems various types of devices (metal-oxide semiconductor field-effect transistors, bipolar transistors, sensors, actuators, microelectromechanical systems, lasers) may be on the same chip, some of which are 3D structures in nature. Therefore, not only materials combinations (integrated materials) are required for optimal device performance of each type but also process technologies for 3D device fabrication are essential. Wafer bonding and layer transfer are two of the fundamental technologies for the fabrication of advanced microsystems. In this review, the generic nature of both wafer bonding and hydrogen-implantation-induced layer splitting are discussed. The basic processes underlying wafer bonding and the layer splitting process are presented. Examples of bonding and layer splitting of bare or processed semiconductor and oxide wafers are described.     

采用偏振分光棱镜的光桥式补偿技术

介绍了一种使用偏振分光棱镜的新型光桥式补偿技术。研究了棱镜消光比变化引起的误差。使用该补偿结构的光纤压力传感器已实际应用于石油化工部门油罐储量计量，其现场运行长期稳定性优于０．２％。     

晶界层陶瓷慢极化机理

在Ｍａｈａｎ的理论中计入电流流过陶 的晶界时所引起的压降并加以改进，可以说明三种典型晶支陶瓷的时域介电谱听慢极化响应，由物质常数出发就能经理论计算给出ＳｒＴｉＯ３和ＺｎＯ有两个慢响应峰，而ＢａＴｉＯ３只有一个；ＺｎＯ的低电压峰位于零场，而其余两种陶瓷的低压峰应离开零场位置；理论结果和实验一臻，估强场扌ＺｎＯ和ＳｒＴｉＯ３的昌界层出现空穴区而使材料参数可能发生转折性奇异，单晶界支和多晶界层的不均匀性     

热红外自发辐射偏振特性分析以及验证实验

光波经过反射后具有偏振特性,目前研究表明热红外自发辐射也具有偏振特性。本文结合基尔霍夫定律以及菲涅耳公式对热红外自发辐射偏振特性进行了初步的理论分析和建模仿真。在低温环境下,采取遮挡措施,进行了热红外自发辐射偏振特性的验证实验,对不同表面状态铝板以及太阳能电池板进行了自发辐射偏振数据的采集。实验结果表明:热红外自发辐射具有偏振特性,并与仿真结果具有一致的变化规律,热红外辐射偏振特性受目标表面粗糙度、材料影响并随着发射角的增加,偏振度不断增加。     

Polarization Beam Splitting in Optical Fibre Couplers Due to Form Birefringence

Abstract

Polarization dependent corrections to the scalar coupling coefficients of the fundamental modes on two identical optical fibres are calculated from scalar supermode fields corrected up to first order in weak coupling. The method applies to arbitrary refractive-index profiles.     

一种新型偏振分光棱镜的设计和应用

一种新型的偏振分光棱镜结构,实现了将偏振态相互垂直的光以不同的角度输入后合为一 束的功能,尤其能与双光纤准直器配合使用。通过计算说明二者角度可相互匹配,并分析了在准直器的角度加工出现小的偏差时,通过微量调节输入光束的方向能予以补偿。实验将该棱镜用于偏振光合束器和光学环行器等无源器件中取得了良好效果。     

The Thermomagnetic Instability in Superconducting Films with Adjacent Metal Layer

Dendritic flux avalanches is a frequently encountered consequence of the thermomagnetic instability in type-II superconducting films. The avalanches, which are potentially harmful for superconductor-based devices, can be suppressed by an adjacent normal metal layer, even when the two layers are not in thermal contact. The suppression of the avalanches in this case is due to so-called magnetic braking, caused by eddy currents generated in the metal layer by propagating magnetic flux. We develop a theory of magnetic braking by analyzing coupled electrodynamics and heat flow in a superconductor-normal metal bilayer. The equations are solved by linearization and by numerical simulation of the avalanche dynamics. We find that in an uncoated superconductor, even a uniform thermomagnetic instability can develop into a dendritic flux avalanche. The mechanism is that a small non-uniformity caused by the electromagnetic non-locality induces a flux-flow hot spot at a random position. The hot spot quickly develops into a finger, which at high speeds penetrates into the superconductor, forming a branching structure. Magnetic braking slows the avalanches, and if the normal metal conductivity is sufficiently high, it can suppress the formation of the dendritic structure. During avalanches, the braking by the normal metal layer prevents the temperature from exceeding the transition temperature of the superconductor. Analytical criteria for the instability threshold are developed using the linear stability analysis. The criteria are found to match quantitatively the instability onsets obtained in simulations.     

铁路货车钩缓装置钩尾扁销螺栓断裂原因分析

铁路货车钩缓装置中的钩尾销螺栓在螺杆近方头一侧根部位置发生断裂。采用微观分析方法分析了该螺柱断裂原因。综合分析表明：该断裂螺栓方头一侧可能仅局部加热后锻打成四方头,并发生过热,造成在方头一侧的螺柱根部形成马氏体组织和魏氏体组织过渡的U型区域。不良组织的存在增大了钢的脆性,冷加工性能大大降低,在U型区域和螺柱表面交界处萌生了微细裂纹。当钩尾扁销螺栓在列车运行过程中受到过大的冲击时,该螺栓上的微细裂纹在螺栓靠近方头一侧存在的沿轴向的拉应力和螺栓正常紧固力的合力联合作用下张开并迅速扩展,造成螺栓断裂。     

Theoretical Simulation of Surface Evolution Using the Random Deposition and Surface Relaxation for Metal Oxide Film in Atomic Layer Deposition

Atomic layer deposition (ALD) has become an essential deposition method for forming nanometer scale thin films in the microelectronics industry, and its applications have been extended to multi-component thin films, as well as to single metal oxide films. In order to investigate the development of the surface structure of ultra-thin film qualitatively as well as quantitatively, ALD processes are simulated with a molecular scale. For this simulation, the film materials are deposited on a imaginary substrate that consists of small lattice. The deposition behaviors are described by using random deposition (RD) model or random deposition with surface relaxation (RDSR) model as the ALD growth mode, and the proposed model was applied to the deposition of SrO-TiO2 thin films. Through this work, growth characteristics such as surface morphology, deposited film coverage can be predicted.     

Analysis of a Fibre-optic Ring Resonator with Polarization Effects: Application to Polarization Sensing with Improved Sensitivity

Abstract

A theoretical analysis for a fibre-optic ring resonator is given by assuming a polarization modulation in the loop fibre. If the change in polarization angle θ in the loop is large, the output intensity has two resonance dips separated in phase by an angle equal to 2θ, when the loop phase is scanned from 0 to 2π. When θ is small, the resonator output produces only one resonance dip and the amplitude of this resonance dip is a measure of θ. By placing a polarizer at the resonator output, a resonance peak in the intensity is produced with an amplitude that increases with increasing θ. Such a system has potential applications, for example, in Faraday current sensing, with an increased sensitivity. The effects of birefringence in the loop and the angle of polarization of the input light are also analysed.     

添加Ni中间层镁/钢激光熔钎焊接头的组织和性能

通过添加0.1 mm的Ni片,对AZ31B镁合金板和Q235低碳钢进行激光熔钎焊搭接试验,分析添加Ni中间层后接头的宏观形貌、元素分布与微观组织和力学性能.结果表明:添加Ni中间层的熔钎焊接头焊缝成形良好.焊缝由镁侧焊缝、金属间化合物(IMC)层、钢侧焊缝组成.根据元素分布发现,加入Ni中间层后,在IMC层出现Mg元素向下、Fe元素向上扩散的现象.进一步研究发现,接头镁侧焊缝主要由α-Mg+β-Mg17-Al12)组成;IMC层由Mg2 Ni、AlNi相和(α-Mg+Mg2 Ni)共晶组织组成;钢侧焊缝由Fe-Ni固溶体组成.其中,IMC层中的树枝状的Mg2 Ni有机械咬合的作用,AlNi相对熔钎焊接头具有强化作用,使接头的力学性能提高.随着线能量的增加,接头拉剪强度σb呈现出先增大后减小的趋势.当P=1250 W、v=20 mm·s-1、线能量Q=625 J·cm-1时,添加Ni中间层的镁/钢焊接头的σb最高,达到198 MPa.     

Coupled-wave Analysis of the Bragg Effect Waveguide Coupler

Abstract

A coupled-wave analysis is presented for the Bragg effect waveguide coupler. This device consists of a slanted volume phase grating which is integrated inside the lightguiding layer of an optical waveguide. The wave propagation is described by a set of leaky wave modes. Self-consistency relations are derived to determine the angular mode spectrum and the corresponding radiation loss coefficients. A maximum input coupling efficiency of 80% is predicted for an incident Gaussian beam. The power of a waveguide mode should be emitted into a single output beam reaching an efficiency of almost 100%.     

The Impact of Nuclear Magnetism on Superconductivity in a Metal with Nuclear Electric Quadrupole Splitting: Indium

We report the first investigation of the impact of nuclear magnetism on superconductivity in the tetragonal metal indium. We have measured the superconducting critical field B_c(T) and in its vicinity the nuclear magnetic heat capacity at ultralow temperatures, 170 KT200 mK. We compare the measured quantities with calculations which consider the nuclear magnetic Zeeman and the dominating nuclear electric quadrupole interaction in indium. The heat capacity data support the occurence of a positive sign of the electrical field gradient at nuclear sites and in consequence the existence of a nuclear low spin ground state. Surprisingly, at lowest investigated temperatures, 170 KT1 mK, the reduction of the critical field B_c(T) clearly exceeds the size of the calculated magnetization ₀ M(B_c, T) which is limited by the nuclear low spin ground state. In all other materials the interplay of nuclear magnetism and superconductivity has been studied so far (Al, AuAl ₂ , AuIn ₂ , Rh, and Sn), the bare nuclear magnetization appeared as an upper limit of the reduction of the critical field.     

热铟封技术中多层金属薄膜的研究

在像增强器制备过程中,转移阴极—铟封技术使器件设计更加自由,并能提高器件的增益及时间、空间分辨率。相对于冷压铟封,热铟封技术更加简单实用,设备造价低,因此,在真空光电器件制备领域有着广泛的应用前景。但是,热铟封技术在保证器件气密性方面仍需进一步改善。本文采用真空蒸镀方式,在玻璃上制备了多层金属薄膜,以提高In-Sn合金与玻璃的润湿性能。采用座滴法比较了合金在玻璃及五种膜层结构表面的润湿及铺展性能。利用JSM-6700F型场发射电子扫描显微镜分析了润湿界面特性。结果表明:In-Sn合金与玻璃的润湿性能差,且在封接界面处容易产生孔洞;In-Sn合金在膜层结构玻璃/Cr/Cu和玻璃/Cr/Ni/Cu/Ag上表现出良好的铺展性和润湿性,在封接界面处,合金与薄膜表层结合致密,无缝隙或孔洞出现;器件铟封实验表明,采用膜层结构玻璃/Cr/Ni/Cu/Ag,热铟封制管成品率高,气密性良好。     

具有中间支承的矩形板自由振动分析

应用一般解析解来求解具有中间支承矩形板的自由振动问题。一般解析解能求解任意边界条件矩形板的振动问题,求解过程是将整块板看成是沿中间支承分开的两块板,沿支承边两块板的挠度均等于零,斜度和弯矩均相等,再由全部边界条件和连续性条件可以求解各阶频率和振型。对几种具有简支边,平夹边或自由边的混合边界矩形板进行了计算。     

Electroelastic Analysis of a Piezoelectric Layer with Electrodes

The electroelastic analysis of a piezoelectric layer with two semi-infinite electrodes is made. The layer surfaces are clamped and a voltage is applied between the layer surfaces and the electrodes. By using the integral equation method, the electroelastic field is derived for the cases of crack-type electrodes and of rigid electrodes, respectively. It indicates that the concentration of electric field an electric displacement occurs near the electrode tips for both cases. However, the stresses are bounded for the former, and possess singularity for the latter. The field intensity factors and energy release rate are obtained in explicit form. The counterpart for a single semi-infinite electrode is given.     

基于虚拟仪器的金属材料极化阻力测试系统

本文将虚拟仪器技术引入腐蚀电化学测试,利用笔记本电脑、恒电位仪、数据采集卡及LabVIEW鳊程建立了一个基于恒电位方波的金属腐蚀体系极化阻力测试系统,该系统具有简单、快速和便携的优点,适合现场测试,可以迅速得到极化阻力Rp值和腐蚀速率。     

极化分解与子孔径分析相结合的极化SAR图像分类

本文提出了一种极化SAR图像分类的新方法,该方法将传统极化分解与子孔径分析结合起来.首先将全分辨率极化SAR图像分解成几个子孔径图像,利用子孔径分析对两类非平稳目标进行检测,得到场景中的非平稳目标.然后对全分辨率图像的相干矩阵进行特征分解,得到熵(H)和α角两个参数,并在H-α平面上对地面目标进行分类;最后,将非平稳目标检测结果与H/α分类结果结合起来,对极化SAR图像进行更为精细的分类.仿真结果表明,本文提出的方法取得了更好的分类效果.     

Theoretical Investigation of the Interaction of a Deformed Metal with a Corrosion Medium

We deduce an equation for determination of the electric potential in a deformed metal caused by the redistribution of electric charges in the process of deformation. We assume that the charge density of the crystal lattice is determined by a relative change in the volume, and the charge density of the electron gas is determined by the condition of constancy of the electrochemical potential of electrons over the entire volume of the metal. We formulate conditions for the deformable metal–corrosion medium interface and, as an example, consider an infinite metal body containing a circular hole filled by the corrosion medium.