热处理对钛酸锶钡薄膜光学性能的影响

采用无水溶胶-凝胶技术制备了钛酸锶钡光学薄膜,研究了预处理温度对钛酸锶钡薄膜表面形貌的影响,系统分析了退火温度对钛酸锶钡薄膜的相结构、微观形貌和光学性能的影响。结果表明,膜的物相、结构和形貌均对其光学性能起决定作用,制备致密、均匀的晶态薄膜是使钛酸锶钡薄膜具有高的光学透过率、大的折射率和小的消光系数的关键。通过150℃预处理和850℃退火获得了晶化程度良好,表面形貌平整、致密的钛酸锶钡薄膜,该膜在350~1000nm的最大光透过率为80.72%,在600~1000nm的折射率稳定在约1.93,在400~1000nm范围消光系数稳定在约4×10-5。     

热处理对钛酸锶钡薄膜光学性能的影响

采用无水溶胶-凝胶技术制备了钛酸锶钡光学薄膜,系统研究了预处理和退火温度对钛酸锶钡薄膜的相结构、微观形貌和光性能的影响,优化了薄膜的光学性能,结果表明,膜的结构和形貌直接影响其光学性能。通过150℃预处理和850℃退火获得了晶化程度良好、表面形貌平整致密的钛酸锶钡薄膜。该膜在350-1000nm的最大光透过率为80．72％,在600-1000nm的折射率稳定在-1．93左右,消光系数最小,最小值为4x10-5。     

非晶SrTiO3纳米薄膜退火处理方法的研究

用激光脉冲沉积技术(PLD),以N型(100)Si为基底在300℃下制备100nm非晶STO薄膜,分别用常规退火(CFA),快速退火(RTA)以及激光诱导晶化(LIC)处理将其转化多晶薄膜,用XRD测定薄膜相组分和结晶质量,用AFM观测薄膜表面微结构.比较不同工艺退火对薄膜结晶品质的影响并阐述了各自形核结晶的机理.     

退火处理对TiO2薄膜结构和透射的影响

在常温下,采用射频反应磁控溅射方法在不同溅射功率下于K9双面抛光玻璃基底上制备二氧化钛薄膜.将制备的样品进行450℃退火6h热处理.利用X射线衍射仪(XRD)对比分析了退火前后薄膜的微观结构,采用光栅光谱仪测试了退火前后薄膜样品的透射谱.实验结果表明,退火前薄膜样品是非晶态,退火后薄膜晶化为晶态,但不同溅射功率下制备的薄膜结晶取向有差异;退火热处理对薄膜的折射率有一定影响,表现为退火前后透射谱偏移.     

快速热处理对(Ba,Sr)TiO3薄膜晶化行为的影响

采用射频溅射法在Si(111)基片上制备了(Ba,Sr)TiO3(BST)薄膜,并对制备的薄膜进行了快速退火热处理.采用X射线衍射和原子力显微镜分析了退火温度、退火时间和加热速度对BST薄膜晶化行为的影响.研究结果表明,BST薄膜的晶化行为强烈依赖于退火温度、退火时间和加热速度.BST薄膜的结晶度随退火温度的升高而提高.适当的热处理可降低BST薄膜的表面粗糙度,BST薄膜的表面粗糙度随退火温度的升高经历了一个先降低后增大的过程,但退火后BST薄膜的表面粗糙度都小于制备态薄膜的表面粗糙度.BST薄膜的晶粒尺寸随退火温度的升高经历了一个先增大后减小的过程.随退火时间的延长,BST薄膜的特征衍射峰越来越强,薄膜的晶化程度越来越高.随退火时问的延长,BST薄膜的晶粒尺寸和表面粗糙度也经历了一个先增大后减小的过程.BST薄膜的晶粒大小主要由退火温度决定.高的升温速率可获得较小的晶粒.     

交替中间热处理BST薄膜介电性能研究

用溶胶凝胶(Sol-Gel)法制备了三种钛酸锶钡(Ba_0.6Sr_0.4TiO₃, BST)薄膜：常规的四层薄膜, 在逐层制备过程中,对首层薄膜进行中间热处理(Preheat-treatment, PT)的四层薄膜及间隔或交替地对奇数层薄膜进行中间热处理（称为交替中间热处理(Alternate-preheat-treatment, APT)）的八层薄膜. 用XPS研究薄膜表面成分化学态, 用SEM和AFM观察表面形貌及晶化, 并进行了介电性能测试. 结果表明, 常规薄膜介电性能差; 经PT, 薄膜裂纹和缩孔显著减少,形貌明显改善,表面非钙钛矿结构显著减少, 介电性能明显提高; 经APT, 薄膜形貌进一步改善,平均晶粒大小约30nm,非钙钛矿结构进一步减少, 介电损耗明显降低,介电稳定性和介电强度大幅度提高. APT为制备退火温度低及结构均匀致密的纳米晶BST薄膜提供了新方法, 可满足低频实用要求. 退火温度对薄膜厚度的影响也进行了讨论.     

硅(100)衬底表面快速热退火制备硒纳米晶薄膜的结晶动力学

采用超高真空气相沉积系统在Si(100)衬底上制备非晶硒(Se)薄膜,然后快速热退火制得Se纳米晶薄膜。SEM观察结果表明,当热退火温度高于140℃,薄膜表面形貌从条状裂纹逐渐变成孤立的六角块状结构。Raman和XRD测试分析发现,退火后的Se纳米晶均为三角晶型结构,当退火温度高于140℃时,Se开始沿(100)方向择优取向结晶。分析得出,在Si(100)衬底上的Se晶粒(100)晶面的激活能比(101)晶面的激活能低,因而在(100)面上的结晶速率比(101)面上的结晶速率大,使得Se在(100)方向择优结晶。笔者认为这是因为Si(100)衬底对Se的结晶具有诱导作用,致使硒的结晶具有各向异性。     

退火工艺对钛酸锶钡铁电多层膜结构与物性的影响

立足于无铅型钛酸锶钡(BST)铁电多层膜的制备及物性研究.采用溶胶-凝胶方法制备了Ba0.9Sr0.1TiO3铁电多层膜,并利用快速退火炉对多层膜进行热处理.重点分析两种不同热处理工艺对钛酸锶钡多层膜微观结构及相关物理性能的影响.通过X射线衍射(XRD),扫描隧道显微镜(SEM)及可见光范围反射谱测量等的表征方法,研究钛酸锶钡铁电多层膜微观结构的演化和形成机理,为制备性能优良的钛酸锶钡铁电多层膜提供基础数据.     

后处理工艺对BST薄膜残余应力的影响的分析

采用射频磁控溅射在Pt/Ti/SiO2/Si（100）衬底上制备了钛酸锶钡（BST）薄膜，利用气氛炉对薄膜进行晶化处理，晶化后薄膜的应力采用XRD表征。研究其残余应力随退火气氛、退火温度以及退火降温速率变化的趋势，通过对不同后处理工艺参数实验结果的分析，得到较优化的工艺参数，以制备较小残余应力的优质BST薄膜。     

纳米硅镶嵌复合薄膜退火前后的微结构及发光特性研究

采用减压化学气相沉积方法,依靠纯N2稀释的SiH4气体的热分解反应,在玻璃表面生长了纳米硅镶嵌的复合薄膜.实验研究了退火前后薄膜样品的结晶状态和光致发光特性.结果表明,未退火样品的光致发光特性随沉积温度升高反而减弱.退火温度Ta＞600℃时,晶化趋势明显,Ta＜600℃时,退火温度对晶化的贡献不大,但提高退火温度或延长退火时间可以增加PL强度.同时在退火样品中发现Si-Ox的单晶结构.通过Raman、PL、TEM的分析比较,认为在退火前后分别有两种不同的发光机制起主导作用.     

Influence of different annealing processes under various atmospheres on the oxidation behaviour of γ-TiAl

Abstract

A detailed study of the oxidation behaviour of bare γ-TiAl based alloy Ti–45Al–8Nb under various conditions, such as different atmospheres, pressures, temperatures (900°C, 1000°C) and times (100–200 h) is presented. Under high vacuum conditions (10^–6 mbar) a continuous zone of α-₂Ti₃Al was formed at the surface with an oxygen-enriched phase on top. No oxide scale formation was obvious. During thermal treatment under Ar-atmosphere at low vacuum pressure (approximately 50 mbar) mainly nitrides (TiN, Ti₂AlN) and Al₂O₃ particles were formed at the surface with an α-₂layer below. Annealing γ-TiAl in hydrogen atmosphere (about 1040 mbar) led to the formation of a thick reaction zone. A TiO₂ layer was formed on top, followed by a mixed oxide scale. Beneath that scale a thick region with alumina, σ–Nb₂Al and α-₂Ti₃Al was observed.

Moreover, the oxidation behaviour of several thermally pre-treated samples was tested by cyclic oxidation at 900°C in air. The microstructure of the oxide scale formed after testing can be compared with that of non pre-treated material. γ-TiAl annealed under high vacuum conditions exhibits the lowest oxidation rate, while the mass gain of specimens pre-treated under Ar-atmosphere increased rapidly in the first cycles. All pre-treated specimens exceeded a lifetime of 600 cycles at minimum. The reference material failed after 520 cycles.     

铁电薄膜退火方法的研究

以锆钛酸铅薄膜（PZT）为例，分析了国内外铁电薄膜退火的各种方法。针对解决铁电薄膜基底高温生长工艺与硅集成电路承受温度较低的不兼容及器件性质劣化的难题，分别对普通炉子退火、快速热退火及激光退火进行了详细的分析比较。激光低温退火技术有望成功地在未来应用PZT铁电薄膜制作组件时，增加其制备工艺设计的弹性和可行性。     

Task assignment problems in distributed computing systems by simulated annealing

Abstract

The stochastic, heuristic search algorithm called simulated annealing is considered for the problems of static task assignment in distributed computing systems. The purposes of task assignment problems are to assign modules of programs over a set of interconnected processors in order to both maximize the utilization of processors and minimize interprocessor communication costs. This problem has been proven to be NP‐hard. Although simulated annealing has been applied to a broad class of combinatorial optimization problems, but it requires a long computation time in order to converge to the globally optimal solution. In this paper, we design a very efficient annealing schedule with good move generation strategies and use the concept of specific heat and the frozen condition to obtain near‐optimal solutions for task assignment problems with a significantly large reduction in the number of iterations.     

Experiments and simulations of directionally annealed ODS MA 754

Both directional and isothermal annealing experiments have been performed on the hot-rolled ODS nickel-based superalloy MA 754. Directional annealing of MA 754 produced an elongated, coarse grain structure with a {1 1 0}1 0 0 texture for all hot-zone velocities examined, with the grain aspect ratio and twin boundary density decreasing with increasing hot-zone velocity. Isothermal annealing also produced elongated structures, but with larger grain aspect ratios and a stronger {1 1 0}1 0 0 texture. In order to elucidate the results of the experimental studies, a front-tracking computer-based model [H.J. Frost, C.V. Thompson, C.L. Howe, J.H. Whang, Scripta Metall. 22 (1988) 65–70] was modified to simulate the directional/isothermal annealing processes for materials with particles. Simulations of directional annealing with particles aligned in the direction of hot-zone movement could produce (at the appropriate hot-zone velocities) columnar grain structures with some finer grains clustered around the particles. Contrary to experimental observations, simulations of isothermal annealing in similar particle-containing material did not produce columnar grain structures, but equi-axed grains whose size was defined by the spacing between the lines of particles. Thus, the simulation results suggest that it is the texture, and not the particles, of the hot-rolled MA 754 that leads to a columnar grain structure.     

富Ni的NiAl退火组织和室温力学性能

快速凝固Ｎｉ－３４．６ａ．％Ａｌ薄带经１５２３Ｋ退火２ｈ并以较快速度冷却扣形成以ＮｉＡｌ马氏体为基体，γ－Ｎｉ３Ａｌ沿晶界网状分布和少量残β－ＮｉＡｌ的组织，退火，室温弯曲延性良好。     

热蒸发制备CdSe薄膜的退火工艺研究

采用真空热蒸发技术在光学玻璃基底上制备了CdSe薄膜,研究了真空下不同退火温度和退火时间对CdSe薄膜晶体结构和表面形貌的影响。XRD结果表明,在400~500℃范围下退火2h、5h的CdSe薄膜晶型不发生改变,结晶性随退火温度升高而增强,其晶粒尺寸从32nm增加至50nm。SEM结果表明,在450℃下退火2h后的CdSe薄膜表面颗粒分布均匀且排列规则、无裂纹。AFM结果表明,在450℃下退火2h后的CdSe薄膜致密性好,表面粗糙度低(5.19nm)。因此采用真空热蒸发制备的CdSe薄膜的热处理条件确定为:退火温度450℃,退火时间2h。     

工程结构混合离散变量优化的模拟退火方法

本文针对工程结构优化设计中普遍存在的混合离散变量的现象，探索了应用模拟退火算法直接获得最优解的方法，从而不再对离散变量作“规格化”后处理。文中根据混合离散变量的特点，提出了几种邻域状态的产生函数和迭代方案，给出了适宜的模拟退火过程的冷却进度表。算例表明该方法能有效地解决工程结构混合离散变量的优化问题。     

Giant Stress—impedance Effect in Amorphous and Current Annealed Fe73.5Cu1Nb3Si13.5B9 Ribbons

The giant stress-impedance(GSl) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated .The results showed that the GSl effect changed drastically with annealing techniques and the maximum stress impedance ratio of 350% was obtained after optimal conditions of current annealing .The behaviors of the stress impedance vary with densities of annealing current and the stress longitudinally applied during current annealing.The maximum change of stress impedance existed in the sample annealed by high-current-density electropulsing under applied stress of 100MPa.     

热处理对WO3薄膜的结构和气致变色性能的影响

用溶胶－凝胶法在普通钠钙玻璃上制备了WO3薄膜，并分别在250℃，360℃，450℃的空气环境中对薄膜进行了热处理，用SEM，XRD观察了薄膜的表面形貌，分析了薄膜的微观结构及热处理温度和催化剂含量对薄膜的结构和气致变色性能的影响。     

Laser annealing of silicon

In recent years laser processing has attracted much attention in view of its potential use in basic solid-state and material science research as well as in new processing technologies. The dominant feature of laser processing being the deposition of large amounts of energy (a few J/cm²) over very short time scales (a few tens of nanoseconds), it leads to melting of surface layers of solid followed by rapid resolidification. In this article, a few basic consequences of such laser-induced phenomena in silicon are reviewed.