高温车用燃料电池的发展及现状综述

燃料电池车以其能量转化效率高、绿色环保、噪音低等优点，被认为是替代传统化石能源汽车最有前景的新能源汽车。目前车用燃料电池的工作温度一般都低于80℃，低温的工作环境使其面临着诸多问题，如复杂的水管理和CO中毒等。通过提高质子交换膜燃料电池（PEMFC）的工作温度可以缓解这些问题，提高燃料电池的性能。然而，高温的工作环境也会对燃料电池带来诸多挑战，如膜脱水、催化剂团聚、冷启动速度缓慢等。要促进高温（90～120℃）车用燃料电池的快速发展，需要对其问题及解决方法进行分析。本文从电堆比功率、膜电极、双极板、进气方式、加湿方式等方面，介绍燃料电池的发展现状及存在的问题，包括Nafion膜和催化剂的热稳定问题、双极板的耐腐蚀问题、流道的气体分配问题、进气方式和加湿方式的优化以及冷启动问题。指出通过掺杂亲水性氧化物改善Nafion膜的高温性能；将Pt合金化及采用介孔炭提高催化剂的稳定性和电化学活性；镀层不锈钢金属双极板可以增强耐腐蚀性；3D流场等新型流场结构及提高进气温度、速度可以提高气体的均匀性；采用自增湿方式可以简化电堆结构等解决方法，以期对燃料电池车的进一步发展起到引导作用。     

中国无机盐工业发展现状及展望

建国70 a以来中国无机盐工业发展迅猛,取得了巨大成就,中国已成为世界上最大的无机盐生产、出口和消费国。分析了中国无机盐工业生产现状和进出口情况,指出行业存在大宗产品产能过剩、产品精细化率偏低、产业集中度和资源配置率偏低、矿产资源保障能力不足、节能减排任务重、自主创新能力弱等问题,并提出未来发展建议及发展方向。新能源用无机材料、无机粉体功能材料、5G通迅用无机材料、电子化学品和电镀化学品等专用化学品将是未来无机盐工业发展的热点。随着产业链现代化水平的不断提升,将会逐渐实现行业规模化、绿色发展与安全生产。     

氯碱企业快速熔断器运行状况调查报告

以2018年58家氯碱企业供电、整流技术与设备现状调查数据为依据,阐述了国内氯碱企业中快速熔断器的运行状况。调查数据中包括50家氯碱企业的快速熔断器的基本运行数据、投运时间及设备来源等。汇总了各企业在氯碱生产中使用快速熔断器时遇到的问题、发生的故障甚至酿成的生产事故及对氯碱生产造成的影响。并分析了事故发生的原因,提出了预防及解决措施,总结了事故处理经验,旨为氯碱生产提供参考依据。     

退役电池回收产业现状及经济性分析

新能源汽车的快速发展使动力电池回收利用成为研究热点，但关于退役电池回收产业和经济性分析问题研究较少。研究了现阶段国内废旧电池回收产业现状及存在问题，对电池回收利用的经济性及生产经营过程产生的敏感性因素进行分析。同时指出电池回收技术的发展应以“退役动力电池资源再生-高值化锂电原材料”为主线，电池回收企业应积极与新能源汽车行业统筹协调发展、构建区域化回收利用体系、提升产业整体经济性水平，对动力电池回收行业具有一定的指导意义。     

石油化工污水处理技术现状与发展趋势

石油化工生产过程中，会产生大量的废水，这些废水中富含着大量的污染物，若是不进行适当的处理，必然会造成严重的污染问题。近年来，石化工业一直在不断更新污水处理技术，以实现清洁生产的最终目标。针对石油化工污水处理技术进行了简要分析和探讨。     

GK1C型内燃机车频繁停车现象探讨与解决方案

运用过程中各类相关因子的变化,会使得机车柴油机配气相位出现一定程度变化,采取某种措施调整或是处理可以解决动力不足的问题。     

基于目标跟踪的变电站隔离开关状态图像识别方法

为解决变电站中隔离开关状态的自动识别问题，提出了基于目标跟踪的开关分合状态图像识别方法。首先，基于隔离开关开合过程的动态视频，通过 Ｌａｓｓｏ正则化稀疏表示的目标跟踪模型对隔离开关运动轨迹进行识别；其次，利用隔离开关２个闸刀之间的距离自动识别算法获得开关的分合状态。实测结果表明，该方法可快速跟踪开关运行轨迹，实时对变电站中隔离开关状态进行准确识别。     

<i>Claroideoglomus etunicatum</i> improved the growth and saline– alkaline tolerance of <i>Potentilla anserina</i> by altering physiological and biochemical properties

To investigate the effects of arbuscular mycorrhizal (AM) fungi on the growth and saline–alkaline tolerance of Potentilla anserina L., the seedlings were inoculated with Claroideoglomus etunicatum (W.N. Becker & Gerd.) C. Walker & A. Schüßler in pot cultivation. After 90 days of culture, saline–alkaline stress was induced with NaCl and NaHCO₃ solution according to the main salt components in saline–alkaline soils. Based on the physiological response of P. anserina to the stress in the preliminary experiment, the solution concentrations of 0 mmol/L, 75 mmol/L, 150 mmol/L, 225 mmol/L and 300 mmol/L were treated with stress for 10 days, respectively. The mycorrhizal colonization rate, mycorrhizal dependence, chlorophyll content, malondialdehyde content, antioxidant enzyme activities, osmoregulation substances content and water status were measured. The results showed that with the increase of NaCl and NaHCO₃ stress concentration, mycorrhizal colonization rate, colonization intensity, arbuscular abundance and vesicle abundance decreased, and reached the lowest value at 300 mmol/L. Strong mycorrhizal dependence was observed after the symbiosis with AM fungus, and the dependence was higher under NaHCO₃ treatment. Under NaCl and NaHCO₃ stress, inoculation with AM fungus could increase chlorophyll content, decrease malondialdehyde content, increase activities of superoxide dismutase, peroxidase and catalase, increase contents of proline, soluble sugar and soluble protein, increase tissue relative water content and decrease water saturation deficit. It was concluded that salt–alkali stress inhibited the colonization of AM fungus, but the mycorrhiza still played a positive role in maintaining the normal growth of plants under salt–alkali stress.     

热轧层流辊道内冷辊回水结构的优化改进

针对某热轧厂1 580 mm生产线精轧出口层流辊道内冷辊频繁发生操作侧轴承失效问题,对其原因进行了分析,同时核算了内冷辊受热轴向膨胀后操作侧轴承侧向间隙。结果表明:操作侧轴承侧向间隙满足使用要求,轴承失效和辊筒受热膨胀无关;操作侧轴承失效的直接原因是轴套制造精度低导致骨架油封失效、内冷辊高速旋转“吸水”效应,使冷却回水进入轴承座内部,进一步造成润滑不良进而造成轴承失效。为此,对内冷辊回水结构进行了优化改进:在操作侧轴承座端盖和水套之间增加法兰,延长轴套及安装轴套的轴头,在轴头和轴套之间增加O型密封圈。改进后两年的使用周期内没有发生过轴承失效故障。     

Numerical simulation of pharyngeal bolus flow influenced by bolus viscosity and apparent slip

Pharyngeal bolus flow was simulated numerically using a finite element method. The bolus liquids were X-ray medium, glucose, and thickener solutions. For a low-viscosity bolus, the simulation showed a reasonable agreement of bolus velocity with X-ray measurements. The influence of bolus density on swallowing velocity was investigated numerically. Although a higher density resulted in a higher bolus velocity, the increase in velocity was modest. When the bolus viscosity was high, it was necessary to apply the slip boundary condition to obtain an agreement for bolus velocity between the simulation and X-ray measurements. The simulations also showed that the method of characteristic shear rate proposed by Zhu et al., Journal of Texture Studies, 2014, 45, 430–439 is effective for predicting the bolus velocity for shear-thinning fluids. In order to discuss the effect of saliva lubrication and the physical meaning of the characteristic shear rate, an immiscible two-layer flow of the core and wall layer was analyzed theoretically by analogy with mesopharyngeal bolus flow. The characteristic shear rate enabled us to correlate the macroscopic flow behavior and the viscosity of the core layer fluid. Lubrication due to the wall layer caused the apparent slip and enhanced the transfer of viscous core fluid. For viscous fluid that presented a large apparent slip in the two-layer model, the slip boundary condition was needed in the swallowing simulation. The numerical simulation and model flow analysis revealed the usefulness of characteristic shear rate and the importance of saliva-layer lubrication in swallowing.