ZrO2陶瓷颗粒在激光作用下组织形貌演变规律

采用激光表面处理技术制备ZrO_2复合热障涂层可使陶瓷颗粒与金属之间实现冶金结合,增加结合强度,但由于陶瓷颗粒和金属热膨胀系数之间的差异,制备大面积复合热障涂层仍存在比较严重的开裂问题.为降低复合材料层的开裂倾向,更好地控制ZrO_2陶瓷颗粒的离散规律,本文针对激光熔注过程中陶瓷颗粒的熔化问题,采用高速摄像、扫描电子显微镜研究了氧化锆陶瓷颗粒进入熔池前后激光对其形貌与离散规律的影响规律.结果表明,在激光能量密度较低的情况下,激光直接作用于氧化锆陶瓷颗粒会导致单个ZrO_2陶瓷颗粒发生裂解现象;当激光能量密度高于2.5 J/mm~2时,ZrO_2陶瓷颗粒熔化严重并发生球化现象.在激光熔注过程中,由于受到激光和高温熔池的双重作用,氧化锆陶瓷颗粒内部晶粒长大,高能量大尺寸晶界促进了Ti熔体向ZrO_2陶瓷颗粒内部扩散.     

Research on optimizing ore matching technology for 550 m~2 sintering machine

The sinter quality is important for its performance in a blast furnace,and optimizing ore matching is a main way to ensure the quality and yield of sinter ore and to reduce the cost of ore matching.The research on optimizing ore matching for a 550 m~2 sintering machine in Shougang Jingtang was carried out in this paper. Firstly,based on the condition of iron ore resourse in Shougang,sintering properties of various ores,especially the high temperature properties were researched,and basic structure of ore matching was determined according to the mutual complementary properties of assimilation and liquid phase fluidity among Australia ore,Brazilian ore and domestic concentrates,that was Australian ore(50%-60%) + Brazilian ore(40%-30%) + domestic concentrates(about 10%).Secondly,9 groups of ore matching schemes were designed and sintering pot tests were carried out,and then the starting scheme of the 550 m~2 sintering machine was obtained:ore from southern Brazil (20%) +ore from northern Brazil(10%) + semi-limonite(20%) + limonite ore(35%) + domestic concentrates (15%).Thirdly,experiment of optimizing parameters of optimizing basicity,lime ratio,water addition and bed depth were carried out,and 9 groups of ore matching schemes were designed.The results showed that parameters fit for Jingtang currently are as follows:binary basicity is 1.9 - 1.95,lime ratio and water addition is 5%and 7.0% respectively;sintering bed should increase to 800 mm gradually.At last,Jingtang sintering plant was put into production successfully and yields stably,with the bed depth of 800 mm and advanced sintering indexes.     

联合几何畸变校正及定标的B-ISAR稀疏成像算法

针对双基地逆合成孔径雷达(B-ISAR)提出了一种可实现几何畸变校正及定标的稀疏成像算法.首先,根据B-ISAR的成像几何建立了一种基于等效转台的回波模型,推导了B-ISAR成像几何畸变及定标因子与等效转台模型的参数之间的解析关系,从而将B-ISAR几何畸变校正及定标问题转化成了参数估计问题;同时,利用目标散射的稀疏先验,基于最大后验概率准则,将B-ISAR稀疏成像问题以及几何畸变校正和定标问题结合起来变成一个联合优化问题.然后,通过迭代优化的方式交替求解,实现目标稀疏成像的同时,实现了成像的几何畸变校正与定标.所提算法运算量适中,且具有很快的收敛速度.     

中里坪浆砌石拱坝坝体应力分析和评价

针对中里坪拱坝实际工程情况,运用多拱梁法进行了应力计算和分析,以便掌握坝体在不同荷载组合工况的应力分布状况,为大坝可行性评价及蓄水过程提供理论依据。计算结果表明:(1)中里坪拱坝的主压应力在三种组合工况下均满足规范要求,拱坝结构有一定的安全裕度;(2)主拉应力也都在规范允许范围内。     

Low-Temperature Fabrication and Enhanced Ferro- and Piezoelectric Properties of Bi3.7Nd0.3Ti3O12 Films on Indium TinOxide/Glass Substrates

Bi_3.7Nd_0.3Ti₃O₁₂ (BNT0.3) films were fabricated on indium tin oxide/glass substrates using a metal organic decomposition method at temperatures ranging from 500° to 650°C. A predominantly (100)-oriented BNT0.3 film can be obtained even at 550°C. The growth mode of the predominantly (100)-oriented BNT0.3 films fabricated by the sequential layer annealing method was discussed based on the structure evolution with the annealing temperature and the film thickness. The largest values of the remanent polarization and piezoresponse are observed in the BNT0.3 film annealed at 650°C, which can be ascribed to the grain growth and the release of the in-plane residue tension stress.     

Aging-Induced Double Ferroelectric Hysteresis Loops and Asymmetric Coercivity in As-Deposited BiFe0.95Zn0.05O3 Thin Film

The BiFe_0.95Zn_0.05O₃ (BFZO) thin film was fabricated on indium tin oxide/glass substrate using a metal organic decomposition method combined with sequential layer annealing. Double ferroelectric hysteresis loops were observed in the as-deposited film, indicating that the film is partially aged. This aging phenomenon can be attributed to the formation of defect complexes between oxygen vacancies and acceptors of     in the film. The nonreversible transition from double ferroelectric hysteresis loop to the single one can occur during the course of increasing the applied electric field. More importantly, an asymmetry of the coercive field can be found to be strongly dependent on the magnitude and frequency of the electric field. This phenomenon was discussed based on the asymmetric driving force for domain backswitching in BFZO film with a preferential polarization.     

针对eLORAN系统窄带干扰的权函数陷波算法

针对增强型罗兰(eLORAN)系统的带内干扰问题,该文基于陷波滤波器(NF)原理提出一种抗带内窄带干扰的自适应权函数陷波算法(WF-NF)。首先,该文分析讨论了NF算法在eLORAN系统中的适用性及检测频差引起的伪收敛问题;之后通过增加频差权函数,推导出新的WF-NF算法,解决了固有频差导致的陷波逻辑缺陷;随后,提出梯度跳跃收敛优化技术,改进了权系数收敛速度过慢的问题;最后,通过多种环境下的实验验证了算法的稳定性、多元适用性及实用性。分析结果表明,WF-NF算法能够克服检测频差的实际问题,实现高效的干扰跟踪及滤除,同时也可以补偿干扰检测精度,进而为后续的信号处理流程提供保障。     

ADSL应用技术研究

本文在分析各种常用互联网接入技术的基础上．阐述了ADSL技术的特点，重点论述了应用ADSL时在硬件连接技术、软件设置技术和路由配置技术方面进行的研究，最后介绍了ADSL技术在引滦工程的应用情况。     

澄清耐火材料质量检验中的几个错误观念

目前 ,在耐火材料企业中存在着一些错误的质量检验观念 ,如 :“检验结果发生异议时 ,加倍复验”、“按比例进行抽检 ,即百分比抽检”、“产品抽检合格 ,批中产品都合格”、“样本的合格品率等于提交批的合格品率”。本文就此予以澄清 ,同时对抽样检验理论进行阐述 ,建议在耐火材料质量检验中普及抽样检验 ,彻底根除目前耐火材料质量检验的错误观念     

LF精炼钢包用铝尖晶石浇注料的研制与应用

通过调整富铝尖晶石及镁砂的粒度组成和添加量,优化浇注料的基质组成,使研制的富铝尖晶石浇注料具有优良的抗渣侵蚀性和抗剥落性。该浇注料在首钢第三炼钢厂９０ｔ ＬＦ炉包壁使用,取得了较好的使用效果。