Effect of heavy cryo-rolling on the evolution of microstructure and texture during annealing of equiatomic CoCrFeMnNi high entropy alloy

The effect of cryo-rolling on the evolution of microstructure and texture during annealing was investigated in equiatomic CoCrFeMnNi high entropy alloy. For this purpose the alloy was cold- and cryo-rolled to 90% reduction in thickness followed by annealing at temperatures ranging from 700 °C to 1200 °C. The two alloys showed the development of predominantly brass type deformation texture consistent with profuse nano-twin formation reported in this alloy. The cryo-rolled material showed significantly finer grain size after different annealing treatments as compared to the cold-rolled alloy. This could be attributed to finer microstructure in the cryo-rolled material providing greater number of available sites for nucleation. The recrystallization texture of cold- and cryo-rolled materials showed the presence of similar texture components indicating that cryo-rolling had limited effect on the formation of annealing texture. The volume fractions of different texture components did not reveal significant dependence on the annealing temperature. The evolution of texture could be explained on the basis of absence of strong preferential nucleation and growth during annealing.     

Characterization of anodic SiO2 films on P-type 4H-SiC

The physical and electronic properties of 100-120-nm thick anodic silicon dioxide film grown on p-type 4H-SiC wafer and annealed at different temperatures (500, 600, 700, and 800 °C) have been investigated and reported. Chemical bonding of the films has been analyzed by Fourier transform infra red spectroscopy. Smooth and defect-free film surface has been revealed under field emission scanning electron microscope. Atomic force microscope has been used to study topography and surface roughness of the films. Electronic properties of the film have been investigated by high frequency capacitance-voltage and current-voltage measurements. As the annealing temperature increased, refractive index, dielectric constant, film density, SiC surface roughness, effective oxide charge, and leakage current density have been reduced until 700 °C. An increment of these parameters has been observed after this temperature. However, a reversed trend has been demonstrated in porosity of the film and barrier height between conduction band edge of SiO₂ and SiC.     

Influence of process variables on growth of ZnO nanowires by cathodic electrodeposition on zinc substrate

Influence of the deposition duration and electrolyte concentration on the structural and morphological features of the ZnO thin films, grown by cathodic electrodeposition on zinc substrate followed by annealing in air at 400 °C, have been investigated. The surface morphology of the as-synthesized films shows two distinct features, presence of ‘2-dimensional nanosheets’ on the area near the electrolyte-air interface and ‘granular’ nanostructures, below the interface region. However, upon annealing, the formation of ZnO nanowires, possessing length of several microns and diameter less than 20 nm, on the entire substrate is observed. The X-ray and selected area electron diffraction patterns clearly confirm the polycrystalline nature of the ZnO nanowires.     

影响退火钢板表层Mn析聚的因素及提高2030钢板抗锈蚀能力的对策

从2030与1420两冷轧单元工况上的差异出发,考察了2030CAPL和2030BAF中影响Mn等易氧化元素在钢板表面富集的因素.结果表明,退火温度、退火时间、退火前清洗介质中含Si与否、钢卷冷轧时的变形量等对Mn等的析聚有较大的影响;宝钢2030冷轧板表面Mn等元素的过度析聚也归因于退火温度(过高)、退火时间(过长)、CAPL退火前清洗介质中含有Si、钢卷冷轧时的变形量与退火温度时间的不完全匹配等的共同作用.考虑到2030冷轧单元对这些关键因素进行严格地控制和匹配较为困难,提出了"退火后轻微酸洗处理"的提高2030冷轧板抗锈蚀能力的措施.     

柳钢冷轧板带退火工艺和设备选择的探讨

介绍冷轧板带退火工艺的特点，探讨柳钢冷轧板带退火的设备选择。     

“模拟退火”在全局最优化中的应用和改进

电信网优化问题经合理简化可转换为四维整数区域上的全局最优化问题.但该问题的费用函数是极端‘病态’的,采用基本的‘模拟退火’算法效年低,解的稳定性也不够满意.本文针对基本 SA 算法的弱点探讨了几种改进方法,使算法效率和解的稳定性都有所改善.     

一种用于GSM系统的神经网络均衡器

在泛欧GSM移动通信系统中，由于存在码间干扰，必须采用信道均衡技术。常用的最大似然序列估计(MLSE)均衡器采用维特比算法(VA)，它只能用于具有较小时延扩展的信道。本文给出了一种适用于GSM系统的部分连接神经网络均衡器．其复杂度与信道的时延扩展成正比．特别适用于具有较大时延扩展的恶劣信道。为了消豫神经网络局部极小点引起的性能恶化．我们采用了均场退火技术。本文提出的均衡器既适于用模拟集成电路实现．又适于用数字集成电路实现。计算机仿真表明本文的方法具有比最常用的16状态和32状态VA更好的性能。     

Ion implantation of semi—insulating InP materials

The methods for protecting InP surface against degradation during annealing,including encapsulant and encpsulant-free techniques;rapid thermal an-nealing of InP implanted layers;implanted ion species and some profiles of typical dopants,etc.,they are all the key techniques concerning ion implantation into se-mi-insulating InP,and have been reviewed synthetically as well.     

Rapid thermal annealing effects on the photoluminescence properties of molecular beam epitaxy-grown GaIn(N)As quantum wells with Ga(N)As spacers and barriers

This article describes the effects of rapid thermal annealing (RTA) on the photoluminescence (PL) emission from a series of GaIn(N)As quantum wells. Indium compositions of both 20% and 32% were examined with nominal N compositions of 1% or 2%. The N location was varied within our quantum structure, which can be divided into three regions: (1) quantum well, (2) Ga(N)As spacer layers at the barrier-to-well interface and well-to-barrier interface, and (3) barriers surrounding each quantum well. Eight combinations of samples were examined with varying In content, Ga(N)As spacer layer thickness, N content, and N location in the structure. In the best cases, the presence of these Ga(N)As spacer layers improves the PL properties, due to annealing, with a reduction in the emission wavelength blueshift by ～400 Å, a reduction of the decrease in the full-width at half-maximum (FWHM) by ～5 meV, and a threefold reduction of the increase in integrated intensity. It was also observed that relocating N from the quantum wells to the barriers produces a comparable emission wavelength both before and after annealing. Our results further show that the composition of incorporated N in the material is most influential during the stages of RTA in which relatively small amounts of thermal energy is present from our lower annealing times and temperatures. Hence, we believe a low thermal-energy anneal is responsible for the recovery of the plasma-related crystal damage that was incurred during its growth. However, the In composition in the quantum well is most influential during the latter stages of thermal annealing, at increased times and temperatures, where the wavelength blueshift was roughly independent of the amount of incorporated N. As a result, our investigations into the effects of RTA on the PL properties support other reports that suggest the wavelength blueshift is not due to N diffusion.     

自适应分区段混合粒子群优化算法

该算法先利用Christos贪心算法将整个搜索区域进行自适应分区段,在每一区段内搜索出最优位置,然后将各区段的最优位置组成一新微粒群,继续搜索全局最优位置。而在每个区段中,又将模拟退火算法引入到粒子群优化(PSO)之中,通过Boltzmann机制选择每一区段中局部极值,使新算法在不同阶段兼顾对多样性和收敛速度的不同要求。与其他混合PSO算法相比,仿真实验表明,新算法具有较高的解精度,能较好地解决过早收敛问题。