残余应力对TiC_p－AIN复合材料的影响

本工作采用热压工艺，以Ｙ＿２Ｏ＿３为烧结添加剂，在１８５０℃下制备ＴｉＣ＿ｐ－ＡＩＮ复合材料。结果表明：复合材料的密度、抗折强度、断裂韧性受第二相ＴｉＣ＿ｐ的影响，通过合理工艺因素选择，可以使复合材料的抗折强度和断裂韧性比基体ＡＩＮ材料分别提高４０％，８０％，达到４３８ＭＰａ，５．５９ＭＰａ·ｍ￣（１／２）。由ＸＲＤ内应力分析和ＴＥＭ显微结构测试结果可知，复合材料性能改善原因在于高弹性用量的ＴｉＣ引入以及ＡＩＮ和ＴｉＣ热膨胀系数不匹配导致的残余内应力。     

传统PLC远程通信的改进方法

传统PLC远程通信是基于相应PLC远程通信硬件模块或者构建VPN通道形式进行通信,在成本上需要支付相应的硬件费用与通信费用,相应硬件模块占用额外空间,并且某些单位出于安全角度并不对外开放VPN通道.该文主要设计思路为,在WinCC7.0软件中运用VB语言编程访问SQL Server 2005实现报表输出,通过编写Windows脚本定时自助发送文档报表的形式来解决远程通信问题.省去了部分通信硬件,方法简单实用,不需要现场人员具有较高的计算机水平,跳过VPN通道,克服传统方式存在的不足.     

非饱和黏性土直剪强度特性及其修正分析

为研究非饱和黏性土的直剪强度特性,采用非膨胀土及两种不同干密度的弱膨胀土进行了包含低应力状态下8种不同上覆压力的直剪试验。试验结果表明,随着上覆压力的增大,最大剪应力及所对应的剪切位移逐渐增大,试验中低应力状态下测定的土体凝聚力小于高应力状态,且试验中的上覆压力对膨胀性土凝聚力的影响大于非膨胀性黏土;而低应力状态下测定的土体内摩擦角大于高应力状态。对直剪试验中上下盒接触面积减小对抗剪强度参数测定的影响进行了分析,分析表明,接触面积减小对抗剪指标有影响,但极其微小。提出对膨胀土边坡浅层破坏进行稳定性分析时应采用低应力下的抗剪强度参数。     

钛酸钡基铁电材料的介电非线性研究

通过A位或B位掺杂改性得到的钛酸钡基铁电材料,在外加直流偏置电场作用下,具有介电常数非线性可调的优异介电性能,可以广泛地应用于压控可调陶瓷电容器和微波可调器件领域。针对钛酸钡基铁电材料的介电非线性特性,讨论了BaTiO_3基铁电材料分别在铁电相、顺电相以及相转变温度场附近的介电非线性机理和相关理论;结合笔者近年来有关介电非线性研究的实验结果和相关文献报道,综述了不同A位离子(如Sr~(2-)和Ca~(2-)等)或B位离子(如Zr~(4 )和Sn~(4-)等)掺杂的BaTiO_3基铁电材料体系的介电非线性研究现状,分别对不同物质形态(陶瓷块体、薄膜和厚膜)的BaTiO_3基铁电材料的介电非线性研究及其应用进行了对比分析;并对钛酸钡基铁电材料今后的发展趋势和研究方向进行了展望。     

冶钢宾馆中央空调的化学清洗

通过对中央空调冷冻水、冷却水两个系统结垢原因的分析，简单论述了化学清洗的机理、方式方法，以及清洗在维护中央空调系统正常运行中的重要性。     

Coupling-and-decoupling: A hierarchical model for occlusion-free object detection

Handling occlusion is a very challenging problem in object detection. This paper presents a method of learning a hierarchical model for X-to-X occlusion-free object detection (e.g., car-to-car and person-to-person occlusions in our experiments). The proposed method is motivated by an intuitive coupling-and-decoupling strategy. In the learning stage, the pair of occluding X?s (e.g., car pairs or person pairs) is represented directly and jointly by a hierarchical And–Or directed acyclic graph (AOG) which accounts for the statistically significant co-occurrence (i.e., coupling). The structure and the parameters of the AOG are learned using the latent structural SVM (LSSVM) framework. In detection, a dynamic programming (DP) algorithm is utilized to find the best parse trees for all sliding windows with detection scores being greater than the learned threshold. Then, the two single X?s are decoupled from the declared detections of X-to-X occluding pairs together with some non-maximum suppression (NMS) post-processing. In experiments, our method is tested on both a roadside-car dataset collected by ourselves (which will be released with this paper) and two public person datasets, the MPII-2Person dataset and the TUD-Crossing dataset. Our method is compared with state-of-the-art deformable part-based methods, and obtains comparable or better detection performance.     

Mixed H2/H∞ robust model predictive control with saturated inputs

In this paper, we investigate the mixed H₂/H_∞ robust model predictive control (RMPC) for polytopic uncertain systems, which refers to the infinite horizon optimal guaranteed cost control (OGCC). To fully use the capability of actuators, we adopt a saturating feedback control law as the control strategy of RMPC. As the saturating feedback control law can be effectively represented by the convex hull of a group of auxiliary linear feedback laws, the auxiliary feedback laws allow us to design the actual feedback control law without consideration of the input constraints directly to achieve the improved performance. Moreover, we suggest the relative weights on the actual and auxiliary feedback laws to the RMPC, which in turn improves the closed-loop system performance. Furthermore, an off-line design of the proposed RMPC is also developed to make it more practical. Numerical studies demonstrate the effectiveness of the proposed algorithm.     

速凝水泥浆体的速凝原因及机理探讨

本文从物理和化学角度讨论速凝水泥浆体的速凝原因及机理。速凝剂加水形成的OH-使水泥水化诱导期不再出现,活性水泥矿物激烈水化形成的大量水化物胶结未反应矿物和集料,这是速凝的主因。也可把速凝看成是混凝土中游离水消耗至某种程度的结果,物理耗水(润湿、蒸发等)与化学耗水同样重要。快速水化放热升温是速凝的重要原因。AFt相是常用速凝剂作用下形成的速凝快硬主相。合理选用活性矿物、促凝化合物、稠化剂、润湿分散剂和超塑化剂可配出优质水泥速凝剂。     

炭黑/蒙脱土/SBR纳米复合材料的性能研究

采用少量（0～5份）蒙脱土（MMT）等量替代炭黑，考察炭黑／MMT／SBR纳米复合材料的硬度、强伸性能、耐磨性能和耐屈挠龟裂性能。结果表明，随着炭黑／MMT并用比的减小，炭黑／MMT／SBR纳米复合材料的拉伸强度、撕裂强度和耐屈挠龟裂性能明显提高，耐磨性能有所下降，但降幅不大。     

高浊度微污染黄河水的处理工艺

在混凝处理中采用5%的清水回流与PAC+HPAM联合投加相结合的方法,形成高浊度微污染黄河水的处理工艺。应用该技术对高浊度水进行生产性试验,除浊效果与传统工艺相比约提高40%～50%,对有机物和NH3-N的去除率也有所提高,同时可使出水的致突变活性呈阴性。