CeO2–ZrO2-promoted CuO/ZnO catalyst for methanol steam reforming

The Cu-based catalysts with different supports (CeO₂, ZrO₂ and CeO₂–ZrO₂) for methanol steam reforming (MSR) were prepared by a co-precipitation procedure, and the effect of different supports was investigated. The catalysts were characterized by means of N₂ adsorption–desorption, X-ray diffraction, temperature-programmed reduction, oxygen storage capacity and N₂O titration. The results showed that the Cu dispersion, reducibility of catalysts and oxygen storage capacity evidently influenced the catalytic activity and CO selectivity. The introduction of ZrO₂ into the catalyst improved the Cu dispersion and catalyst reducibility, while the addition of CeO₂ mainly increased oxygen storage capacity. It was noticed that the CeO₂–ZrO₂-containing catalyst showed the best performance with lower CO concentration, which was due to the high Cu dispersion and well oxygen storage capacity. Further investigation illuminated that the formation of CO on CuO/ZnO/CeO₂–ZrO₂ catalyst mainly due to the reverse water gas shift. In addition, the CuO/ZnO/CeO₂–ZrO₂ catalyst also had excellent reforming performance with no deactivation during 360 h run time and was used successfully in a mini reformer. The maximum hydrogen production rate in the mini reformer reached to 162.8 dm³/h, which can produce 160–270 W electric energy power by different kinds of fuel cells.     

伞形风力机尾流特性及输出特性研究

为适应分布式风力发电机的恶劣应用环境,同时满足功率调控以及风机自我保护的需求,提出了一种新型伞形风力机。为研究伞形风力机风轮收缩角对尾流特性和输出特性的影响,分别进行了数值模拟和风洞试验。研究结果表明：伞形风力机风轮收缩角增大后,扫掠面积减小,尾流直径减小,尾流轴向影响范围增大,速度恢复减缓,同时会导致叶尖涡强度减小,中心涡强度先增大后减小,但是中心涡强度一直大于叶尖涡强度,所以叶根后的速度亏损要一直大于叶尖后的速度亏损。此外,风洞试验也验证了风轮收缩角对功率控制的有效性。     

普适计算环境下位置模型研究进展

位置模型是实现普适计算/物联网环境下物理世界与信息系统融合的核心。从位置模型基本理论和方法、位置推理能力、位置信息表达方法、基于本体位置模型、地理空间本体等方面深入分析了位置模型国内外研究进展,尤其是对现存的一些著名基于本体位置模型进行了比较分析。针对现有位置模型缺乏统一概念模型,普遍存在位置逻辑简单、推理能力弱等问题,指出综合运用位置理论、本体论、地理空间等多学科交叉融合研究手段构建具有推理能力的统一位置模型的研究思路。     

连铸大包回转台回转轴承故障原因分析

结合舞钢炼钢厂连铸大包回转台的实际运行情况,分析了连铸大包回转台发生回转轴承故障的原因,认为安装保养维护欠缺是连铸大包回转轴承故障的主要原因。提出了加强设备巡检、制定合理使用周期、提高装配水平、严格执行回转轴承安装要求、定期测量和调整回转轴承安装基准面等改进措施,实施后轴承使用周期提高I倍以上。     

A review of platinum-based catalyst layer degradation in proton exchange membrane fuel cells

Catalyst layer degradation has become an important issue in the development of proton exchange membrane (PEM) fuel cells. This paper reviews the most recent research on degradation and durability issues in the catalyst layers including: (1) platinum catalysts, (2) carbon supports, and (3) Nafion ionomer and interfacial degradation. The review aims to provide a clear understanding of the link between microstructural/macrostructural changes of the catalyst layer and performance degradation of the PEM fuel cell fueled with hydrogen under normal operating or accelerated stress conditions. In each section, different degradation mechanisms and their corresponding representative mitigation strategies are presented. Also, general experimental methods are classified and various investigation techniques for evaluating catalyst degradation are discussed.     

基于PLC的自动称重系统

介绍了一种基于PLC的双工位自动称重系统的组成及其工作原理,并对控制系统的硬件及程序做了详细分析。实践表明,该系统性能可靠、吞吐量大、精度高、成本低廉,具有很好的经济效益。应用该系统可取代传统作业中＂粮食拆包—周转散装车—地中衡计量＂等多道环节,提高了生产效率,降低了劳动强度,为实现＂四散＂作业奠定了基础。     

GIS1基因对酿酒酵母耐受性的研究

该研究主要通过过表达GIS1基因来提高酿酒酵母的耐受性。在GIS1基因的N端加入强启动子PGK1p来实现GIS1基因的过表达,然后通过稀释点板实验来对比其对热激、乙醇、渗透压以及乙酸的耐受性,同时通过高温生长曲线和高温浓醪发酵测定其高温耐受性。结果表明,在相同的稀释倍数下,55 ℃热击4 min之后菌株AY12a-gis1的生长能力明显优于出发菌株,在含有5%（V/V）乙酸的平板上改造菌和出发菌耐受性相差不大,同时通过38 ℃浓醪发酵实验发现菌株AY12a-gis1的酒精度提高了3.79%,残糖略有下降,且发酵时间与亲本菌株相一致。因此通过过表达GIS1基因得到菌株AY12a-gis1,是对工业乙醇发酵有一定应用价值的优良耐逆性菌株。     

回热器板叠流动特性研究

回热器内交变流动的研究是回热式制冷机研究的重点,采用数值模拟的方法对回热器内交变流动特性进行了研究.结果表明回热器内压力、速度分布不再呈波动状分布,而是近似的呈直线分布.回热器内的交变流动阻力系数是时间与位置的函数,也具有明显的波动性.     

海上中低渗油藏多功能纳米增注体系性能评价及应用

目的 目前部分海上中低渗油藏薄互层较为发育,具有孔隙结构复杂、局部物性差、层内非均质强等储层特征,导致整体呈现“注不进水,采不出油”现状,严重制约了油田开发效果和储量动用程度的提高。针对这些问题,提出了一种新型纳米增注体系,为海上油田中低渗油藏注水开发提供一套有效的解决方案。方法 通过室内实验性能评价方法对体系润湿性、除垢性能、渗透率改善性能进行研究。结果 纳米溶液处理后岩心由亲水变为疏水,平均岩心润湿角提高20°左右,使流过的水分子发生速度滑移,减少流动阻力;纳米溶液有助于剥离后的有机垢分散,洗脱率达到92.3%,避免剥离后有机垢的二次沉淀堵塞,并且能有效溶蚀矿物,溶蚀率达到43%,起到很好的解堵除无机垢效果;岩心经过纳米溶液驱替后,平均渗透率提高32.6%,平均注入压力下降35.9%。结论 现场应用结果表明,该技术可显著提高注水井吸水能力,措施后注入压力下降46.7%,注入量增加8倍,吸水指数提高12.2倍,有效期是常规酸化的4倍以上。     

Genome-Wide Analysis and Profile of UDP-Glycosyltransferases Family in Alfalfa (Medicago sativa L.) under Drought Stress

Drought stress is one of the major constraints that decreases global crop productivity. Alfalfa, planted mainly in arid and semi-arid areas, is of crucial importance in sustaining the agricultural system. The family 1 UDP-glycosyltransferases (UGT) is indispensable because it takes part in the regulation of plant growth and stress resistance. However, a comprehensive insight into the participation of the UGT family in adaptation of alfalfa to drought environments is lacking. In the present study, a genome-wide analysis and profiling of the UGT in alfalfa were carried out. A total of 409 UGT genes in alfalfa (MsUGT) were identified and they are clustered into 13 groups. The expression pattern of MsUGT genes were analyzed by RNA-seq data in six tissues and under different stresses. The quantitative real-time PCR verification genes suggested the distinct role of the MsUGT genes under different drought stresses and abscisic acid (ABA) treatment. Furthermore, the function of MsUGT003 and MsUGT024, which were upregulated under drought stress and ABA treatment, were characterized by heterologous expression in yeast. Taken together, this study comprehensively analyzed the UGT gene family in alfalfa for the first time and provided useful information for improving drought tolerance and in molecular breeding of alfalfa.