开口截面钢-混凝土组合梁受扭的试验分析

为研究钢-混凝土组合梁在不同加载方式下的受扭性能,完成了6根钢-混凝土组合梁的弯扭试验和纯扭试验,其中2根梁的扭矩直接作用于工字钢梁上,其余4根梁则由钢梁和混凝土翼缘板作为整体共同受扭。试验结果表明,当扭矩直接作用于钢梁上时,混凝土翼缘板通过栓钉对钢梁的扭转提供约束,从而使钢梁的抗扭承载力比纯钢梁的提高2倍以上。在试验参数相同时,混凝土翼缘板和钢梁作为整体复合受扭时组合梁的开裂扭矩及极限抗扭承载力比扭矩直接作用于钢梁时的分别提高86%和39%。分析了两种不同加载方式下钢-混凝土组合梁受扭和受弯承载力的变化。建立了扭矩直接作用于钢梁上时极限扭矩的计算模型及计算公式。对整体受扭时组合梁的弯矩相关性进行了分析,并建立了相关曲线公式。计算结果与实测值吻合较好。     

超高压输变电工程放线作业图自动绘制研究

为有效提高超高压输变电工程架线施工中放线作业图的绘制效率及准确度,结合实际工作经验,提出了放线作业图的自动绘制方法.利用AutoLISP语言编程实现AutoCAD图形数据的自动读取,利用C＋＋编程实现数据的自动处理,利用EXCELL数据控制AutoCAD图形生成,从而实现放线作业图的自动绘制.实际应用验证了该方法的可行性与有效性.     

地埋管换热器连续与间歇运行对换热能力影响

针对夏季工况，对地埋管换热器连续运行工况、间歇运行工况下的换热能力进行了实验研究。     

降低准均质稀燃汽油机NOx排放的电控系统研制

为了配合稀NOx吸附-还原催化转化器的正常工作,开发了一套稀燃汽油机电控系统.该系统不仅可以任意设定汽油机浓、稀燃的空燃比大小和间隔时间长短,而且可以使稀NOx吸附-还原催化转化器在稀燃时,控制汽油机按稀燃状态运行;而在浓燃还原再生过程中,电控系统自动调小节气门开度和点火提前角,使得汽油机对外输出的扭矩稳定.将该系统应用于一台丰田8A-FE16气门EFI汽油机,实验结果表明,研制的稀燃电控系统,达到了设计的要求.     

常温和高温下冷成型薄钢板抗剪连接件的性能

冷成型钢屋面板可以通过粉末冶金射钉或自攻螺钉直接与钢桁架上弦杆连接。对常温和高温下射钉和螺栓连接的剪切性能进行了试验研究和有限元分析。螺栓连接的研究中对承载能力的4个部分(包括薄钢板与螺杆间的承载能力、垫圈与薄钢板之间摩擦力、薄板与厚板之间的摩擦力、薄板倾斜的承载力)进行了定性和定量分析。射钉连接的研究表明,垫圈、射钉、薄板材和支承板之间具有较强的相互作用。在射钉推入过程中出现的隆起,将导致材料中厚钢板承载力提高,对连接的承载能力提高有积极作用。     

Application of the third theory of quantification in coal and gas outburst forecast

The essential principles of the third theory of quantification are discussed, the concept and calculated method of reaction degree are put forward which extend the applying range and scientificalness of the primary reaction. Taking the Zhongmacun Mine as example, on the base of analyzing the rules of gas geology synthetically and traversing the geological factors infecting coal and gas outburst, the paper adopts the method of combining carving up statistical units with the third theory of quantification, screens out 8 sensitive geological factors from 11 geological indexes and carries through the work of gas geology regionalism to the exploited area of Zhongmacun according to the researching result. The practice shows that it is feasible to apply the third theory of quantification to gas geology, which offers a new thought to screen the sensitive geological factors of gas outburst forecast.     

An efficient poly(amic acid) salt-stabilised palladium nanocatalyst with excellent recyclable performance for Suzuki–Miyaura coupling reactions under mild conditions

Highly dispersed poly(amic acid) salt-stabilised palladium nanoparticles(PdNPs/PAAS) were synthesised via a facile reduction strategy in aqueous media at room temperature and characterised by transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and inductively coupled plasma optical emission spectrometer. The nanoparticles were used as catalyst for Suzuki–Miyaura coupling reaction to synthesise biphenyl compounds in short reaction time and high yields under mild conditions, benefiting from highly efficient quasi-homogeneous catalytic activity. The catalyst could be recycled 5 times without obvious loss attributing to the pH response of the PAAS.     

黄土滑坡工程地质问题分析研究

近年来,黄土滑坡成为我国西北地区最为严重的地质灾害之一。随着工程活动的加强,黄土滑坡成为近年地质研究的热点问题。2012年在对麟游县一后侧山体滑坡进行了多次现场调查和滑坡特征测量后获得了详细的野外勘察资料。基于现场工作,初步分析了降雨、地下水、地震等导致滑坡机制,通过工程实例,归纳出有效地黄土滑坡治理方案。     

Production of 4-Hydroxybutyl Acrylate and Its Reaction Kinetics over Amberlyst 15 Catalyst

Esterification of acrylic acid (AA) with 1,4-butanediol (BD) was carried out over a solid acid catalyst to produce 4-hydroxybutyl acrylate (HBA), an environmentally benign coating agent. The Amberlyst 15 catalyst was more active for the reaction than other ion exchanged resin catalysts such as Amberlyst 35 and DOWEX HCR-S(E). The quasi-homogeneous model was chosen to express the esterification reaction kinetics over Amberlyst 15. The stirring speed was changed from 300 rpm to 750 rpm and the reaction rate showed no influence of external mass transfer. The reaction temperature was varied from 100°C to 120°C to calculate activation energies of the reactions. The calculated activation energies were 58.3 kJ/mol and 86.7 kJ/mol for HBA and BDA (1,4-butanediol diacrylate, by-product) productions, respectively. The catalyst concentration was also changed from 0.0043 g/ml to 0.0171 g/ml to find its effect on the rate constant. The complete kinetic equation of esterification to produce HBA over the Amberlyst 15 catalyst based on the quasi-homogeneous model was developed.     

剩余电流断路器在安装和使用中应注意的事项

论述了为确保剩余电流断路器的正常工作需要合理地选择剩余电流断路器的动作特性的必要性,即根据用于间接接触保护、直接接触保护,或用于漏电火灾保护,应选用不同的动作电流和不同的动作时间.此外,还需要正确安装和接线,根据不同的电源系统及设备的情况进行接线.列举了一些错误接线的例子.最后还介绍了剩余电流断路器脱扣后如何寻找故障的步骤.