初始织构对高温轧制AZ31镁合金板显微组织与织构影响的EBSD研究

本文采用EBSD方法表征分析了不同初始取向的AZ31镁合金原料板材经300℃热轧69％后得到的终轧产品的显微组织与织构差异,考察了热轧变形条件下原料的初始织构对热轧成品板材的影响.结果表明,原料的初始织构对终轧板材的显微组织与织构影响不大,但对材料的显微组织界面分布有一定影响.通过高温大变形量变形,不同初始织构的原料均...     

纹理特征在多光谱图像分类中的应用

文中介绍了几种纹理特征提取方法，并将图像中的纹理信息作为重要的特征参与多光谱图像分类的过程，通过与单纯基于像元光谱信息的分类结果的比较，证明了此方法可以改善分类的效果。     

The effects of substrate bias,substrate temperature,and pulse frequency on the microstructures of chromium nitride coatings deposited by pulsed direct current reactive magnetron sputtering

Recently, great attention has been devoted to the pulsed direct current (DC) reactive magnetron sputtering technique, due to its ability to reduce arcing and target poisoning, and its capability of producing insulating thin films. In this study, chromium nitride (CrN) coatings were deposited by the bipolar symmetric pulsed DC magnetron reactive sputtering process at different pulse frequency, substrate bias voltage, and the substrate temperature. It was observed that the texture of CrN changed from (111) to (200) as substrate temperature increased to 300°C as deposited at 2 kHz without substrate bias. With increasing pulsing bias and pulse frequency of target, predominated (200) orientation of CrN film was shown due to the ion bombardment/channeling effect to preferentially sputter those unaligned planes. For the CrN coatings deposited with pulsed biasing, the grain size decreased with increasing pulse frequency and substrate bias, whereas the surface roughness showed a reverse trend. The deposition rate of the CrN films decreased with increasing pulse frequency. It was concluded that the pulse frequency, substrate bias, and substrate temperature played important role in the texture, microstructure, and surface roughness of the CrN coatings deposited by the pulsed DC magnetron sputtering process.     

基于MATLAB的谐波齿轮传动柔轮变形研究

针对弹性波发生器的提出,建立了双波谐波齿轮传动杯型柔轮变形与变形力的计算模型,并对传动比为100、XB1单级谐波减速器80机型的柔轮进行了变形量与变形力测试实验。通过应用MATLAB软件对测得的实验数据进行拟合分析,将实验得到的实验曲线与柔轮变形与变形力计算模型的理论曲线进行比较分析,对柔轮变形与变形力计算模型进行了适当修正,为新型弹性波发生器的设计提供了理论依据。     

Growth of CdTe Films on Amorphous Substrates Using CaF<Subscript>2</Subscript> Nanorods as a Buffer Layer

Continuous biaxially textured CdTe films were grown on biaxial CaF₂ buffer layers. The CaF₂ nanorods were grown by oblique angle vapor deposition and possessed a {111} 〈121〉 biaxial texture. The CdTe film was deposited by metal organic chemical vapor deposition (MOCVD). Film morphology and the CdTe/CaF₂ interface were studied by scanning electron microscopy and transmission electron microscopy. Characterization showed that small CdTe grains formed initially from the CaF₂ surfaces. These small grains then merged into large columnar grains during growth. Analysis revealed that the crystalline orientation of the CdTe film followed the biaxial texture of the CaF₂ nanorods.     

An Airborne Radar Clutter Tracking Algorithm Based on Multifractal and Fuzzy C-Mean Cluster

For an airborne Iookdown radar, clutter power often changes dynamically about 80 dB with wide distributions as the platform moves. Therefore, clutter tracking techniques are required to guide the selection of const false alarm rate （CFAR） schemes. In this work, clutter tracking is done in image domain and an algorithm combining multifractal and fuzzy C-mean （FCM） cluster is proposed. The clutter with large dynamic distributions in power density is converted to steady distributions of multifractal exponents by the multifractal transformation with the optimum moment. Then, later, the main lobe and side lobe are tracked from the multifractal exponents by FCM clustering method.     

交互性纹理合成

扩充了Efros与Freeman的图片缝合算法,添加了图形用户界面,从而可以动态地改交参数,并对算法做了一些改进,增强了用户对纹理合成的可控性并丰富了合成纹理的多样性.     

低碳钢中磷的偏聚与再结晶织构

本文用正、倒极图和ODF法研究了低碳钢板在不同冷轧和再结晶退火条件下,磷对再结晶织构的影响。用金相术、扫描电镜和电子探针研究了磷在钢中的分布和显微组织。结果发现,磷促进了与轧向平行的一组〈001〉和与轧面法向平行的一组〈111〉纤维织构的生成;这种作用与预退火温度密切相关,在390和590℃进行预退火就呈现,在490℃就抑制。在促进织构生成的预退火温度时产生晶内磷偏聚的异常显微组织。并认为这种纤维织构的形成与晶内磷偏聚有关。     

A customized low-rank prior model for structured cartoon–texture image decomposition

The mathematical characterization of the texture component plays an instrumental role in image decomposition. In this paper, we are concerned with a low-rank texture prior based cartoon–texture image decomposition model, which utilizes a total variation norm and a global nuclear norm to characterize the cartoon and texture components, respectively. It is promising that our decomposition model is not only extremely simple, but also works perfectly for globally well-patterned images in the sense that the model can recover cleaner texture (or details) than the other novel models. Moreover, such a model can be easily reformulated as a separable convex optimization problem, thereby enjoying a splitting nature so that we can employ a partially parallel splitting method (PPSM) to solve it efficiently. A series of numerical experiments on image restoration demonstrate that PPSM can recover slightly higher quality images than some existing algorithms in terms of taking less iterations or computing time in many cases.     

逐像素纹理合成的生成式信息隐藏

修改式信息隐藏会对嵌密载体视觉质量造成较大 影响且易留下修改痕迹;纹理构造式 信息隐藏生成的都是非自然纹理;纹理拼接式信息隐藏由给定样例图产生类自然纹理,通过 缝合线算法来拼接纹理小块,不可避免地会产生缝合痕迹和重复纹理模式,从而不能对秘密 信息进行掩盖。针对以上问题,提出逐像素纹理合成的生成式信息隐藏。在嵌密时,首先将 秘密信息编码为密钥图像上的坐标以避免秘密信息直接信道传输,其次引入多备份,将坐标 进一步编码为给定样例图像的高频颜色序列,并由密钥伪随机放置在空白待合成纹理图像上 ,最后按逐像素纹理合成策略来生成含密纹理图像。在提取时,根据密钥提取颜色序列,然 后结合多备份区间扩展策略由样例图像恢复坐标并依据密钥图像提取秘密信息。理论和实验 表明,所提方法通过逐像素纹理合成,不会留下明显拼接痕迹和重复模式且秘密信息完全依 赖于密钥,具备一定的抗攻击能力和较高的安全性。