Effects of particle size and dispersion methods of In2O3‐SnO2 mixed powders on the sintering properties of indium tin oxide ceramics

Three group samples were used to investigate the effects of particle size and dispersion methods of In₂O₃‐SnO₂ mixed powders on the sintering properties of ITO ceramics by BET, SEM, XRD, and EPMA, etc. High‐density (99.8% of TD) ITO ceramics, with dimensions of 350 × 250 × 8 mm³ for the industrial application, were obtained by the mixed powders of In₂O₃ calcined at 1000°C and SnO₂ with BET 6.0 ± 0.5 m²/g and collocation use of ball mill for 300 minutes, stirred mill for 60 minutes, and sand mill for 3 minutes. The results indicate that: (i) the larger the SnO₂/In₂O₃ particle size ratio, the higher the density of ITO ceramics, (ii) the dispersion of mechanical ball‐mill methods for nanosized In₂O₃ and SnO₂ powders is beneficial to the densification and structural homogeneity, and (iii) the smaller the relative grain size, the more uniform the distribution of grain size.     

Effects of mechanical activation on physicochemical properties and alkaline leaching of hemimorphite

Effects of mechanical activation on physicochemical properties and alkaline leaching of hemimorphite from Lanping, Yunnan province were studied. The results showed that both dry milling and mechano-chemical milling could enhance zinc extraction rate and shorten the leaching time. Scanning electron microscope (SEM), particle size distribution (PSD), X-ray diffraction (XRD) analysis demonstrated that different milling times and modes could form different morphologies, particle size distributions and crystal structures, thus influence zinc recovery differently.     

Densification mechanisms and microstructural evolution during spark plasma sintering of boron carbide powders

Micron-sized boron carbide (B₄C) powders were subjected to spark plasma sintering (SPS) under temperature ranging from 1700 °C to 2100 °C for a soaking time of 5, 10 and 20 min and their densification kinetics was determined using a creep deformation model. The densification mechanism was interpreted on the basis of the stress exponent n and the apparent activation energy Q_d from Harrenius plots. Results showed that within the temperature range 1700–2000 °C, creep deformation which was controlled by grain-boundary sliding or by interface reaction contributed to the densification mechanism at low effective stress regime (n = 2,Q_d = 459.36 kJ/mol). While at temperature higher than 2000 °C or at high stress regime, the dominant mechanism appears to be the dislocation climb (n = 6.11).     

焊管生产用带钢铣边机设计研究

阐述了铣边要在国内外发展状况,分析了铣边机的主要特点,基本结构形式,铣削速度的选择和铣边机设计的主要注意事项,并对铣边机应用于焊管机组上对带钢实行不剪边工艺作了一些探讨。     

PLC在电气自动化控制系统中应用范例

介绍安钢六机六流小方坯自动控制系统的设计方案及配置,并针对系统运行中出现的问题,进行控制措施的改进。     

Microstructure and Mechanical Properties of TiC-Reinforced Al-Mg-Sc-Zr Composites Additively Manufactured by Laser Direct Energy Deposition

In order to refine the microstructure and improve the performance of direct energy deposited (DED) additively manufactured Al-Mg-Sc-Zr alloy, TiC-modified Al-Mg-Sc-Zr composites were prepared by DED and the effect of TiC content on the microstructure and performance was studied. In the absence of TiC particle, the microstructure of Al-Mg-Sc-Zr alloy prepared by DED consisted of fine grains with average size of 8.36 μm, and well-dispersed nano-Al₃(Sc,Zr) particles inside the grains and Mg₂Si phase along the grain boundaries. With the addition of 1 wt% TiC, the microstructure of TiC/Al-Mg-Sc-Zr prepared by DED became finer apparently compared with that without TiC; while the further increase of TiC content to 3 wt%, the microstructure of TiC/Al-Mg-Sc-Zr prepared by DED became coarser with appearance of a new kind of needle-like (Ti,Zr)₅Si₃ phase. Also, the addition of TiC decreased the porosity of Al-Mg-Sc-Zr prepared by DED. Simultaneously, after the addition of TiC, the tensile strength increased from 283.25 MPa to 344.98-361.51 MPa, and the elongation increased from 3.61% to 9.58-14.10%. The potential mechanism of the microstructure evolution and strength improvement was discussed. This research will provide new insights into the available metal matrix composites by laser additive manufacturing (LAM).     

基于深度学习的稀疏矩阵向量乘运算性能预测模型

稀疏矩阵向量乘（SpMV）是求解稀疏线性方程组的计算核心,被广泛应用在经济学模型、信号处理等科学计算和工程应用中,对于SpMV及其调优技术的研究有助于提升解决相关领域问题的运算效率。传统SpMV自动调优方法基于硬件平台的体系结构参数设置来提升SpMV性能,但巨大的参数设置量导致搜索空间变大且自动调优耗时大幅增加。采用深度学习技术,基于卷积神经网络,构建由双通道稀疏矩阵特征融合以及稀疏矩阵特征与体系结构特征融合组成的SpMV运算性能预测模型,实现快速自动调优。为提高SpMV运算时间的预测精度,选取特征数据并利用箱形图统计SpMV时间信息,同时在佛罗里达稀疏矩阵数据集上进行实验设计与验证,结果表明,该模型的SpMV运算时间预测准确率达到80%以上,并且具有较强的泛化能力。     

在全国煤矿瓦斯治理工作体系"双百工程"建设会议上的讲话

一、严格要求、加强引导，瓦斯治理工作体系建设起步良好继2005年全国煤矿开展瓦斯治理攻坚战至2007年底基本实现“争取用两年左右时间，使煤矿重特大瓦斯爆炸事故有较大幅度下降”的阶段性目标之后，各地区、各单位按照2008年7月份“辽宁现场会”的部署，认真贯彻落实“先抽后采、     

借鉴外国经验建立适合我国国情的煤矿安全监察体系

分析了世界主要产煤国家煤矿安全状况，研究了美国煤矿安全监察的立法历史、机构设置、2000年的工作任务和财政预算情况，提出了构建适合我国国情的煤矿安全监察体系的9点意见。     

锚栓柱板型装配式可绿化挡墙设计与应用研究

锚栓柱板型装配式可绿化挡墙由上下立柱构成,桩与桩间采用倾斜搁板连接,其在提高预制程度和生态性的同时,也提高了施工效率与经济性。以浙江省某高速公路挡土墙设置工程为背景,首先使用Midas Civil进行数值模拟分析,然后对预制标准化进行研究,最后通过横向比较,明确该型挡墙在公路工程中的应用前景。数值模拟结果表明此结构有较高安全性,锚栓柱板型装配式可绿化挡墙在某高速互通区工点可靠性高,可行性好。针对该挡墙结构特性,总结了其预制关键技术以及施工关键技术;经比较可得,在挡墙使用高度大于2.5 m时,此类挡墙经济效益最高。该型挡墙的应用有助于工点提高生态价值,降低建设成本。本研究成果可为公路工程工业化建造提供参考。