Modulation of electrical transport in calcium cobaltite ceramics and thick films through microstructure control and doping

Ca₃Co₄O₉ is a promising p-type thermoelectric oxide material having intrinsically low thermal conductivity. With low cost and opportunities for automatic large scale production, thick film technologies offer considerable potential for a new generation of micro-sized thermoelectric coolers or generators. Here, based on the chemical composition optimized by traditional solid state reaction for bulk samples, we present a viable approach to modulating the electrical transport properties of screen-printed calcium cobaltite thick films through control of the microstructural evolution by optimized heat-treatment. XRD and TEM analysis confirmed the formation of high-quality calcium cobaltite grains. By creating 2.0 at% cobalt deficiency in Ca_2.7Bi_0.3Co₄O_9+δ, the pressureless sintered ceramics reached the highest power factor of 98.0 μWm^?1 K^-2 at 823 K, through enhancement of electrical conductivity by reduction of poorly conducting secondary phases. Subsequently, textured thick films of Ca_2.7Bi_0.3Co_3.92O_9+δ were efficiently tailored by controlling the sintering temperature and holding time. Optimized Ca_2.7Bi_0.3Co_3.92O_9+δ thick films sintered at 1203 K for 8 h exhibited the maximum power factor of 55.5 μWm^?1 K^-2 at 673 K through microstructure control.     

粒度控制——页岩、煤矸石空心砖原料制备的关键

阐述了页岩、煤矸石的原料粒度对制砖性能的影响,介绍了几种典型的控制颗粒粒度的工艺方案;简要分析了几种筛分机械的优缺点,着重介绍MVS电磁振动高频振网筛在几个使用现场的应用结果,为制砖企业解决原料生产的难题提供了办法。     

筛查基因突变的新技术——循环双脱氧指纹图谱法及其应用

建立了适用于大批量标本基因突变筛查的双脱氧指纹图谱法即ｄｄＦ。该技术民测定ＤＮＡ序列的双脱氧末端终止法及ＳＳＣＰ二者长处于一身，即只作一个双脱氧末端终止反应，然后将反应产物在与ＳＳＣＰ相同的电泳条件下进行聚丙烯酰胺凝胶电泳，这样有突变的样品不会漏检，阳性检出率高达１００％。     

Improving human robot collaboration through Force/Torque based learning for object manipulation

Human–Robot Collaboration (HRC) is a term used to describe tasks in which robots and humans work together to achieve a goal. Unlike traditional industrial robots, collaborative robots need to be adaptive; able to alter their approach to better suit the situation and the needs of the human partner. As traditional programming techniques can struggle with the complexity required, an emerging approach is to learn a skill by observing human demonstration and imitating the motions; commonly known as Learning from Demonstration (LfD). In this work, we present a LfD methodology that combines an ensemble machine learning algorithm (i.e. Random Forest (RF)) with stochastic regression, using haptic information captured from human demonstration. The capabilities of the proposed method are evaluated using two collaborative tasks; co-manipulation of an object (where the human provides the guidance but the robot handles the objects weight) and collaborative assembly of simple interlocking parts. The proposed method is shown to be capable of imitation learning; interpreting human actions and producing equivalent robot motion across a diverse range of initial and final conditions. After verifying that ensemble machine learning can be utilised for real robotics problems, we propose a further extension utilising Weighted Random Forest (WRF) that attaches weights to each tree based on its performance. It is then shown that the WRF approach outperforms RF in HRC tasks.     

Group‐in‐a‐Box Meta‐Layouts for Topological Clusters and Attribute‐Based Groups: Space‐Efficient Visualizations of Network Communities and Their Ties

An important part of network analysis is understanding community structures like topological clusters and attribute‐based groups. Standard approaches for showing communities using colour, shape, rectangular bounding boxes, convex hulls or force‐directed layout algorithms remain valuable, however our Group‐in‐a‐Box meta‐layouts add a fresh strategy for presenting community membership, internal structure and inter‐cluster relationships. This paper extends the basic Group‐in‐a‐Box meta‐layout, which uses a Treemap substrate of rectangular regions whose size is proportional to community size. When there are numerous inter‐community relationships, the proposed extensions help users view them more clearly: (1) the Croissant–Doughnut meta‐layout applies empirically determined rules for box arrangement to improve space utilization while still showing inter‐community relationships, and (2) the Force‐Directed layout arranges community boxes based on their aggregate ties at the cost of additional space. Our free and open source reference implementation in NodeXL includes heuristics to choose what we have found to be the preferable Group‐in‐a‐Box meta‐layout to show networks with varying numbers or sizes of communities. Case study examples, a pilot comparative user preference study (nine participants), and a readability measure‐based evaluation of 309 Twitter networks demonstrate the utility of the proposed meta‐layouts.     

仿瓷胶粘剂的研究

本文介绍一种仿瓷环氧胶粘剂,该胶耐酸耐碱,可室温固化,在室温下粘接不锈钢试样,其剪切强度可达30.7MPa;而在130℃时其剪切强度为1.7MPa。可用于修复搪瓷,粘接金属和陶瓷等。     

PC作为S7—200PLC系统人机界面的一种应用实例

在西门子S7—200PLC系统中,通常所配置的人机界面大多采用西门子专用的TP170、TP27、OP37等系列触摸屏。一旦这些触摸屏发生故障和损坏,难以采购和维修,且备件成本较高。本案例采用当今流行的通用PC机来代替TP27和OP37等专用HMI设备,并实现了PC机与S7—200PLC之间的数据通信,为PLC系统触摸屏的通用化改造提供了一个应用实例。     

基于μC/OS的嵌入式系统中的触摸屏驱动及其应用

μC/OS是源码公开的实时嵌入式操作系统,可移植,可固化,可裁减,该文重点介绍了在该系统下,触摸屏的工作原理及触摸屏的驱动及应用,并同时给出了设计方法。     

基于MPI协议的S7—300PLC与多主站通讯的实现

本文介绍了基于MPI协议的西门子S7—300PLC与工控机和触摸屏实现数据通讯的应用实例及其主要设置。为在组态王软件平台下采用MPI协议实现S7—300PLC与多主站通讯提供了一种有一定参考价值的方法。     

板式叠层筛网粘接技术的改进

钻井液振动筛是油田钻井固控系统中的关键设备，而筛网又是振动筛的主要结构部分，提高筛网的使用寿命是提高钻井速度、降低钻井成本的重要途径，为了提高筛网粘接质量，便于实现自动化操作，本文通过对板式叠层筛网的粘接前处理，胶粘剂调配与涂敷，加压固化，增加涂敷点等方面的工艺改进，使得粘接的叠层筛网使用寿命提高了3－5倍。