鳞片石墨对中间相炭微球织构的影响(英文)

以煤焦油沥青为原料，磷片石墨为添加剂，在410℃温度下反应7h制得了中间相炭微球（MCMBs)。在扫描电子显微镜下对它们的表面和断面进行了分析，并用X射线衍射对其结构进行了研究。结果表明：MCMBS的表面被接近球形的小颗粒所覆盖而呈现出粗糙不平。MCB1（未加石墨）的织构主要是平行层型，而MCB2（加石墨）的织构却是复杂的。加入煤焦油沥青中的大片石墨存在于MCMBs的中心而被认为是它们的核，而小片石墨却不能象大片石墨那样在反应体系内充当核的作用。认为在成核过程中，大片石墨聚集到一起而形成晶种，同时一些低分子量的沥青组分被包裹在这些晶种的内部，石墨片以及它们的职聚体的形状，大小决定了MCMBs的织构。然而，小石墨片只能使MCMBs的织构变得杂乱。MCMBs的XRD谱图表明石墨的添加改变了其结构，并降低了它的石墨化能力和晶体大小。     

含微量稀土元素的Al-Zn-Mg合金的超塑变形机制

用透射电镜详细观察了含微量稀土的 Al-Zn-Mg 合金在超塑变形过程中晶界位错的形态、运动及其与晶界第二相粒子的相互作用情况。发现晶界中的第二相粒子对位错沿晶界运动有明显的阻碍作用。实验还发现在含第二相粒子较多的晶界的超塑性合金中,晶界滑动是通过位错沿晶界运动和晶界的粘滞性流动两种机制同时发生作用进行的,它们相互促进并共同推动了晶界滑动的发展。首次在透射电镜下观察到超塑变形使晶界加宽的现象,在面缩率ψ=72.2%的样品中测得某晶界的宽度约为100nm,从而证实了超塑变形的晶界滑动和晶粒转动机制。     

Synthesis of C_f/TiAl_3 Composite by Infiltration-In Situ Reaction

Infiltration-in situ reaction synthesis of Cf /TiAl3 composite was investigated. The as-cast material was obtained by titanium particles, carbon fibers and pure aluminum. Titanium particles and carbon fibers were mixed and pressed to form a preform firstly, and then molten pure aluminum was pressed into the preform, subsequently, cooled rapidly. In situ reaction samples were obtained by heating the as-cast material from 600 to 1000 °C for 1 h. The microstructural evolution of in situ reaction samples was an...     

Synthesis of monodisperse CdS nanowires and their photovoltaic applications

Cadmium sulphide (CdS) nanowires with a monodisperse diameter of 3.6 nm and an aspect ratio of 10–170 were successfully synthesized using a simple and reproducible hot coordinating solvents method. The morphology and optical properties of the CdS nanocrystals were investigated using transmission electron microscopy (TEM), high-resolution TEM (HRTEM) ultraviolet–visible (UV–Vis) absorption spectroscopy and photoluminescence (PL) spectroscopy. It was found that using a long alkyl chain phosphonic acid-octadecylphosphonic acid (ODPA) causes a low diffusion rate and low reactivity which help to control the morphology of the nanocrystals. The timing of the injection process was also found to have critical effect on the morphology of the nanocrystals. Sharp peaks in both the UV–Vis absorption and PL spectra indicate that the size distribution of the diameter is nearly monodisperse. The photovoltaic properties of photovoltaic devices made with a blend of our nanowires and poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) were also investigated. Devices made with the nanowires were found to have double the I_sc observed in devices made with lower aspect ratio CdS nanorods. The possible reason of low photocurrent and high V_oc is maybe due to the presence of ligand in the nanocrystals.     

在教学网上实现上机操作无纸考试及自动阅卷

在计算机相关课程的教学中 ,为了更好地考查学生的实际动手能力 ,实行上机操作考试无疑是一种非常有效的方法。而探讨如何在教学网上 ,真正实现无纸的上机操作考试 ,以及试后的自动阅卷 ,则更有其现实意义。为此 ,我们编制并调试成功了几个程序 ,实验效果良好 ,而其中的基本操作考试部分较具普遍性和通用性。1　实现方法1.1　准备工作 :1.作学员帐户 :在教学网上 (以ＮＥＴＷＡＲＥ3.12网为例 ) ,为各学员建立其个人帐户及各自的用户目录 ,并赋予应有的权限。例如 ,为学号是 96 0 5 10 1的学员建立帐户 96 0 5 10 1;设其个人目录在ＨＭ1卷上…     

一种山区图像边缘信息的分水岭变换提取方法

为了能够抑制引起过分割的根本原因-噪声和细密纹理,提出了一种改进的提取山区图的山脊线、山谷线的边缘信息的分水岭算法,该算法着重于解决传统分水岭的过分割问题;该算法首先对梯度图进行一种改进的多尺度梯度算子处理,以减小图像噪声对分水岭的过度分割的影响;然后利用基于标记符控制的最小强制技术去除由噪声和不必要的图像细节形成的谷底,使修正后的梯度图像只对应包含区域极大值的标记图像,改进后的方法能准确地提取出所需要的关键边缘信息.     

高职高专“计算机应用”专业教改可行性研究

高职高专“计算机应用”专业建设是通过专业整体建设来强化专业的可持续性发展,提升技能人才培养能力。通过高职高专“计算机应用”专业教改可行性研究,清晰的可以看到随着专业建设的深入与教学实践的展开,最终目标是为社会提供满足职业岗位能力需求的合格的毕业生和技能人才。     

FlexPDA: A Flexible Programming Framework for Deep Learning Accelerators

There are a wide variety of intelligence accelerators with promising performance and energy efficiency, deployed in a broad range of applications such as computer vision and speech recognition. However, programming productivity hinders the deployment of deep learning accelerators. The low-level library invoked in the high-level deep learning framework which supports the end-to-end execution with a given model, is designed to reduce the programming burden on the intelligence accelerators. Unfortunately, it is inflexible for developers to build a network model for every deep learning application, which probably brings unnecessary repetitive implementation. In this paper, a flexible and efficient programming framework for deep learning accelerators, FlexPDA, is proposed, which provides more optimization opportunities than the low-level library and realizes quick transplantation of applications to intelligence accelerators for fast upgrades. We evaluate FlexPDA by using 10 representative operators selected from deep learning algorithms and an end-to-end network. The experimental results validate the effectiveness of FlexPDA, which achieves an end-to-end performance improvement of 1.620x over the low-level library.     

基于反演多参数体约束地质建模的水平井预警技术 ——以玛湖地区致密砂砾岩油藏为例

针对玛湖地区致密砂砾岩油藏储层横向变化快、井间构造和储层预测难度大、优质储层钻遇率低等问题,采用反演多参数体约束地质建模,实现对优质储层三维空间分布的刻画,为水平井预警调控提供重要的依据.通过在油层之上建立预警标志层,根据标志层实钻数据更新局部速度场、构造和地质模型,提前预警靶点深度和水平段倾角关键参数变化,并根据井轨...