电抗器用环氧树脂体系配方及固化工艺的研究

环氧树脂具有良好的电气绝缘性能,在干式空心电抗器生产中被大量使用。由于配方和固化工艺决定树脂固化物的性能,因此研究环氧树脂体系的配方和固化工艺具有重要的工程意义和实用价值。以理论为依据计算了环氧体系的理论配比,并结合实际确定出生产用的实际配比;同时从升温、保温、降温3个过程出发,制定出环氧树脂体系的固化制度。     

高分辨SPI/TOFMS的研制及VOCs分子式确定

单光子能量10.6eV的真空紫外灯可电离大部分的挥发性有机物,生成分子离子,几乎无碎片,谱图简单。本文介绍了实验室自制的真空紫外灯单光子电离反射式飞行时间质谱仪的原理、仪器结构及初步结果。测试仪器分辨率超过4000(FWHM),质量精度优于6ppm。苯的检出限可至52ppbv。将仪器用于香烟烟气和聚氯乙烯(PVC)热解产物的检测。结果表明,单光子软电离源与高分辨质谱的结合,可直接用于复杂挥发性有机物(VOCs)分子式的确定。     

基于ANSYS Workbench的箱型伸缩吊臂动态特性研究

大型化、高速化逐渐成为起重机的一个发展趋势,这些都会加剧整机的动态响应。为研究铁路起重机箱型伸缩吊臂在吊重被突然提升离地与吊重悬空静止开始起升两种工况真实动态特性,引入了钢丝绳阻尼系数,建立了运动微分方程,推导出相应工况整个过程的动态载荷的理论公式。公式表明载荷为绕固定值上下振动、振幅不断衰减的周期函数。据此在ANSYS Workbench中建立了铁路起重机箱型伸缩吊臂有限元模型,采用模态叠加瞬态动力学分析法详细研究了不同载荷频率与吊臂固有频率比值对吊臂最大应力的影响,得出频率比与最大应力关系曲线。结果表明,即使动载荷振幅衰减速度较快,在共振区吊臂最大应力同样会超过材料的屈服极限。     

Word2003使用中的几个问题及解决

介绍Word常见的一些问题及解决方法。     

Aflatoxin M 1 contamination in commercial samples of milk and dairy products in Kuwait

As part of the programme on monitoring of environmental contaminants in food stuffs in Kuwait, 54 samples of fresh full cream and skimmed milk, powdered milk, yoghurt, and infant formula were analysed for aflatoxin M 1 (AFM 1 ) by HPLC following sample clean up using immuno-affinity columns. Of samples, 28% were contaminated with AFM 1 with 6% being above the maximum permissible limit of 0.2 μg l -1 . Three fresh cow milk samples collected from a private local producer showed the highest level of 0.21 μg l -1 AFM 1 . There was no contamination with AFM 1 in powdered milk and infant formulas. These results show the necessity of a survey involving a larger number of milk and its products and suggest that presently the contamination of milk and milk products with AFM 1 does not appear to be a serious health problem in Kuwait. Nevertheless, a continuous surveillance programme may be warranted to monitor regularly the occurrence of aflatoxins in the animal feeds responsible for current limited contamination and to note rapidly any worsening in the situation that may depend on market changes or on unfavourable climatic developments.     

Formula One’s new urban economies

The Formula One (F1) industry has become a true microcosm of the world economy, as new business opportunities surface in emerging countries. Until the beginning of the twenty-first century, this sport was mostly relevant to traditional western urban elites, but since then, the F1 calendar has been largely altered to the benefit of ‘dominant-emerging cities’ and to the detriment of more traditional destinations. This article focuses on this urban question through a historical analysis of the F1 circuit’s expansion phases as well as through a study of the current Grand Prix’s estimate sanction fee.     

基于CAXA公式曲线的凸轮轮廓曲线设计与线切割加工

根据凸轮机构从动件的运动规律,提出利用CAXA线切割软件的公式曲线功能进行凸轮轮廓精确设计的方法,同时利用CAXA线切割软件的CAM功能实现了凸轮的数控加工,为研究凸轮机构的数字化设计方法及数控制造技术提供参考.     

Research on the waiting time of passengers and escalator energy consumption at the railway station

Based on the Little Formula and the classical queuing model of multi-channel M|D|n, the relation of the average queue length, the maximum waiting time and the escalator service intensity were identified and the waiting time simulation model was established. With the passenger delivery data at A railway station in China and the probability distribution model of waiting time, a detailed analysis was made on the escalator allocation, power and energy consumption on holidays, ordinary working days and the largest-passengers-volume days; meanwhile, the fixed and variable energy consumption were compared and studied when the waiting time are 5, 10 and 30 s. The result shows that the waiting time settings affect the allocation and the energy consumption of the escalators and the fixed energy consumption takes 70%.     

从恒速升温速率下的DSC曲线峰温计算含能材料放热分解反应动力学参数的理论和数值方法（英）

根据Kooij公式和van't Hoff公式,从恒速升温速率下的DSC曲线峰温导出了计算含能材料放热分解反应动力学参数的两个数学表达式,提出了计算相应动力学参数的数值方法.对1,3,5-三硝基-1,3,5-三氮杂环己酮-2(Keto-RDX),由导出的两个表达式、Kissinger法、Ozawa法、Tang法、Hu-Gao-Zhang法、非线性等转化率积分法(NL-INT)所得的活化能E值彼此接近,表明Kooij's公式中的a值取0.5,van't Hoff公式的b值取0.003,可得到合理的动力学参数.     

蚕丝上浆工艺研究及生产实践

优化蚕丝的上浆配方及工艺参数。分析了蚕丝的结构特点,设计了两种浆料配方,通过浆纱生产实践对比了两种浆料配方的浆纱效果和织造效果,并对压浆力、烘筒温度等工艺参数进行了优化,使蚕丝织物的织造效率达到94%。指出:蚕丝上浆宜选择成膜性好、粘着力强、粘度较低的亲水性浆料为主浆料,上浆时宜控制浆液的pH值为中性,烘筒温度不宜过高,应以提高经纱的耐磨性为主。