无粘结预应力双向板变形计算方法研究

通过6块无粘结预应力双向板试验,研究了影响双向板变形的主要因素;结构形式、预应力筋配筋率,将边梁对简支板跨中最大挠度的影响转化为荷载与支座条件系数来考虑;对两个方面的预应力筋和非预应力筋对简支板跨中最大挠度的影响,用换算配筋率（αpρ）参数来反映,建立了无粘结预应力简支板短期刚度和变形计算公式,计算结果与试验结果吻合较好。     

聚合物/层状硅酸盐纳米复合材料制备方法及性能的研究进展

聚合物 /层状硅酸盐纳米复合材料因其优异的性能是目前材料科学研究的热点。本文介绍了层状硅酸盐的结构、聚合物 /层状硅酸盐纳米复合材料的类型及微观结构 ,重点介绍了聚合物 /层状硅酸盐纳米复合材料制备方法及性能的研究进展 ,指出需根据不同的聚合物 ,寻求经济可行的制备方法     

Composite structure and properties of the pitcher surface of the carnivorous plant Nepenthes and its influence on the insect attachment system

Pitchers of the carnivorous plant Nepenthes have evolved specialized organs serving the purpose of attracting,capturing,retaining and digesting small animals,mostly insects.They consist of several well distinguishable zones,including a leaf-like lid,a collar-like peristome,a slippery zone and a digestive zone,differing in morphology,microstructure,chemical composition and physical properties.Discriminating zones display different functions,and the combined effects of several zones result in great trapping efficiency.The principal aim of this review is to introduce the structure and physiochemical properties of the pitcher surface,as well as the interaction between the pitcher surface and the insect attachment systems.Combining with our present study,the potential application of the pitcher surface being utilized in bionics to manufacture insect slippery trapping plates is discussed,and the original research direction of the pitcher surface and its application on agricultural pest control is highlighted.     

复合地基工程理论研究回顾与展望

复合地基的理论与应用是当前土木工程中比较活跃的研究领域。近十多年来,复合地基技术得到了较大的发展。由于复合地基中设置的增强体不同,因此,各类复合地基的承载机理也不完全相同。本文综述了复合地基的发展和研究现状,指出了复合地基存在的主要问题。     

热处理对Ni-P基镀层耐高温腐蚀磨损性的影响

Ni P化学镀层经过热处理后 ,镀层硬度、耐蚀性、耐磨性得到提高。在Ni P化学镀的基础上 ,加入元素Co和SiC微粒 ,形成Ni Co P SiC复合镀层 ,经过 10 0～ 6 0 0℃回火后 ,与Ni P镀层相比 ,复合镀层表现出高硬度、高温耐磨性变化趋势小的特点 ,尤其经过 30 0℃回火后 ,复合镀层表现出最佳的耐高温腐蚀磨损性     

空气冲旋钻头牙齿失效分析与新材料实验研究

针对目前空气冲旋钻头钻进中牙齿频繁断裂、脱落以及磨损严重,导致破岩效率低、使用寿命短等问题,采用纳米改型技术,在硬质合金中掺杂纳米Al₂O₃制备出Al₂O₃/WC Co纳米/微米复合材料,对其性能、组织结构进行分析,对其耐磨性、耐冲击性进行实验研究,结果表明：加入3%的纳米Al₂O₃并添加适量的抑制剂和稀土元素能明显改善Al₂O₃/WC Co纳米/微米复合材料的组织结构、细化晶粒,复合材料的耐磨性和耐冲击性能得到大幅提高,较硬质合金YG8提高4～8倍。为大幅度提高钻头破岩效率,延长钻头使用寿命提供了可能性。     

A novel graphite/phenolic resin bipolar plate modified by doping carbon fibers for the application of proton exchange membrane fuel cells

In this study, the carbon fibers treated by three methods were selected as a reinforcement to investigate the influence on the properties of composite bipolar plates. The properties and microstructure of the composite bipolar plate were characterized by the four-point probe, universal test machine, contact angle tester and scanning electron microscopy. The optimum treatment methods and the fiber content were analysed. The results showed that the carbon fibers treated by Fenton reagent for 2 ​h exhibited the best performance, which could improve the electrical conductivity and the flexural strength for composite bipolar plate. Besides, the optimal content content of carbon fibers treated by Fenton reagent was 4%. The maximum power density of the PEMFC with the composite bipolar plates could reach 662.75 ​mW ​cm⁻² in H₂-air conditions. Therefore, the phenolic resin/graphite composite bipolar plate modified by doping carbon fibers was a promising candidate for bipolar plate materials for PEMFC.     

两种材料的界面裂纹尖端场分析

均质各向同性弹性含裂纹固体在外载荷作用下裂纹尖端场表现出奇异性。由两种弹性材料组成的界面裂纹结构,除表现出奇异性外,随着向裂纹尖端靠近,裂纹前方出现应力振荡特性和裂纹表面的相对位移相互嵌入现象。本文从破坏力学的角度对有关问题进行了分析讨论,并给出了适当力学模型的有限元法算例。     

煤基固废复合改性剂高温重构钢渣的性能及机理研究

为了促进钢渣和煤基固废的综合利用,研究了煤基固废复合改性剂(CMCSR)(煤气化渣-硅钙渣-煤田区域水库底泥)对高温重构钢渣的胶凝性能和体积稳定性的影响,采用XRD、SEM、EDS等测试方法,对重构钢渣的物相组成、微观结构及高温重构机理进行了分析。发现CMCSR可以提高钢渣的胶凝性能,显著降低了钢渣中f-CaO含量。当重构温度为1250℃,CMCSR掺量为25%时,重构钢渣28d活性指数比原钢渣可提高16.1%,重构钢渣中f-CaO的含量由4.04%降至1.90%,满足GB/T20491-2017《用于水泥和混凝土中的钢渣粉》中f-CaO含量≤3%的要求。CMCSR掺量由15%增加至35%,重构钢渣中形成透辉石(CMS₂)、钙铝黄长石(C₂AS)、C₃A等硅铝基矿物。高温重构过程促使RO相中的FeO转变为镁铁尖晶石(MgFe₂O₄)和磁铁矿(Fe₃O₄)。重构温度为1250℃,掺25% CMCSC的重构钢渣形成结晶良好、粒径可达10μm以上椭圆形的C₂S颗粒。研究表明,掺入煤基固废复合改性剂的高温改性钢渣,其体积稳定性、胶凝活性和易磨性得到了有效改善,从而为钢渣的低能耗细磨加工进行制品开发,或在水泥和混凝土中的直接应用提供了可能,实现了煤基固废与冶金固废的协同利用。     

电流互感器复合误差的准确间接测试法

本文提供一种对电流互感器复合误差进行准确测量的方法．该法是一种间接测量法，是基于对一次线圈和二次线圈间的耦合系数ｋ以及对二次电感量Ｌ２进行测量的方法．根据测出的ｋ和Ｌ２即可准确地算出其复合误差．