一次大到暴雪过程的流型配置及诊断分析

利用常规气象观测资料和NCEP再分析资料,对2012年4月11日出现在宁夏境内的大到暴雪过程进行了流型配置、物理量诊断,并结合卫星和雷达综合分析.结果表明,这次持续性大到暴雪天气过程的出现是在有利环流背景下,400 hPa以下偏西、偏南、东北3支急流或气流强盛,且随高度顺转,是这次大到暴雪过程流型配置的主要特征.大到暴雪的产生需要一定的动力条件.高空辐散、低层辐合的散度场配置,强而深厚的上升气流,对降雪区上空的上升运动非常有利,是降雪天气维持和发展的重要因素.大到暴雪的落区与散度场,水汽通量散度场和垂直速度场高低层的辐散、辐合强度,湿层的厚度及上升运动的强度成正比.通过单站剖面图分析,进一步证实了风的垂直切变是降水维持的一个重要特征.     

应用型本科院校机械专业人才培养模式的探索

随着机械制造业的快速发展,机械类应用型人才的需求越来越大,作为地方型本科院校的机械专业,需调整其人才培养模式和培养方案,以满足市场需求,为地方经济发展服务,为此机电工程系制定了相应的培养目标和培养方案。通过十年的本科教育探索和不断完善,毕业生就业单位的良好反应证明此方案的正确性和可行性。     

铝熔体用稀土熔剂的使用效果及分析

针对我国在铝加工业存在能耗大，环境污染严重和含氢、含杂量高的问题，研究了一种新型溶剂JDN－I。结果发现，该熔剂个有多种功能：覆盖隔热作用，既可保护铝合金免潮湿大气的污染，又能细化晶粒，又可使共晶硅变质；铝熔体的含氢、含杂量降低到极低的水平，确保铝熔体的纯净化；细化变质作用，既可细化晶粒，又可使共晶硅变质；使用简便，不污染环境，在这种熔剂的作用，可使A356铝合金的流动性大大提高，并使抗拉强度度提高7．25％，伸长率提高85．58％。     

P91大管氩电联焊工艺试验

P91马氏体钢在大型火力发电厂中得到广泛的应用。针对φ460mm×47.5mm的P91马氏体厚壁大径管接头在全位置状态下焊接进行了工艺性试验。确定了焊接工艺参数和焊后热处理温度,对接头进行了拉伸、弯曲、冲击等性能试验,观察了接头的微观金相组织。结果表明:焊接接头抗拉强度与弯曲试验结果合格,焊接接头所有区域的组织基本为回火马氏体状态,综合机械性能均能够满足国家标准DL/T868-2004和JB/T 8129-2002等规范要求,同时分析了焊接接头各区组织不同的形成原因。     

YFe1-yCoyO3半导体气敏材料的制备和性能研究

用化学共沉淀法制备了YFe1-yCoyO3（0．0≤y≤0．05）固溶纳米晶微粉，并对其制备条件，物相组成，微结构，电导和气敏效应作了系统研究，结果表明，钴B位掺杂铁酸钇材料呈典型的P型半导体导电行为，同温下固溶体电导不仅大于纯相YFeO3的电导而且随湿度增加其电阻迅速下降，243℃下YFe0.9Co0.1O3传感器元件对乙醇有较高的灵敏度和良好的选择性，有望开发为一类新型C2H5OH3信息敏感材料。     

The concept of synergism in radiobiology]

We have demonstrated previously that pemphigus vulgaris (PV)-IgG induces activation of phospholipase C (PLC), production of inositol 1,4,5-trisphosphate, and a rapid transient increase in [Ca2+]i in cultured human keratinocytes, leading to secretion of plasminogen activator and cell-cell detachment in cell culture. In the current study, to examine the involvement of protein kinase C (PKC) in the mechanism of blister formation in PV, we studied the PV-IgG-induced translocation of PKC isozymes from the cytosol to the particulate/cytoskeleton (p/c) fractions and the activation of PKC in human keratinocytes. Cells cultured in Eagle's minimum essential medium were incubated with PV-IgGs for 30 s, 1 min, 5 min, or 30 min. PV-IgG binding to the cell surface antigen (desmoglein III) induced translocation of PKC-alpha from the cytosol to the p/c fractions within 30 s, with a peak at 1 min that lasted at least 30 min. PKC-delta also was translocated within 1 min and reached a peak at 5 min but was reduced to basal levels at 30 min. Alternatively, PKC-eta translocation to the p/c fraction was induced slowly, taking more than 5 min, and was reduced to approximately half-maximum at 30 min, whereas PKC-zeta translocation reached a maximum at 30 s, rapidly returning to baseline by 5 min after PV-IgG stimulation. The total PKC activity in the p/c fraction also was increased after PV-IgG exposure, peaked at 1 min, and was sustained for at least 30 min. These findings suggest that a unique activation profile of PKC isomers may be involved in mediating the intracellular signaling events induced by PV-IgG binding to desmoglein III in cultured human keratinocytes.     

Tumor necrosis factor-alpha induces apoptosis of human adipose cells

Tumor necrosis factor-alpha (TNF-alpha) production by adipocytes is elevated in obesity, as shown by increased adipose tissue TNF-alpha mRNA and protein levels and by increased circulating concentrations of the cytokine. Furthermore, TNF-alpha has distinct effects on adipose tissue including induction of insulin resistance, induction of leptin production, stimulation of lipolysis, suppression of lipogenesis, induction of adipocyte dedifferentiation, and impairment of preadipocyte differentiation in vitro. Taken together, these effects all tend to decrease adipocyte volume and number and suggest a role for TNF-alpha in limiting increase in fat mass. The aim of the present study was to determine if TNF-alpha could induce apoptosis in human adipose cells, hence delineating another mechanism by which the cytokine could act to limit the development of, or extent of, obesity. Cultured human preadipocytes and mature adipocytes in explant cultures were exposed in vitro to human TNF-alpha at varying concentrations for up to 24 h. Apoptosis was assessed using morphological (histology, nuclear morphology following acridine orange staining, electron microscopy) and biochemical (demonstration of internucleosomal DNA cleavage by gel electrophoresis and of annexin V staining using immunocytochemistry) criteria. In control cultures, apoptotic indexes were between 0 and 2.3% in all experiments. In the experimental systems, TNF-alpha induced apoptosis in both preadipocytes and adipocytes, with indexes between 5 and 25%. Therefore, TNF-alpha induces apoptosis of human preadipocytes and adipocytes in vitro. In view of the major metabolic role of TNF-alpha in human adipose tissue, and the knowledge that adipose tissue is dynamic (with cell acquisition via preadipocyte replication/differentiation and cell loss via apoptosis), these findings describe a further mechanism whereby adipose tissue mass may be modified by TNF-alpha.     

活塞环制造过程中的去锈处理

本文叙述了两种新型的活塞环去锈工艺，说明了该工艺的使用方法及应用范围，采用该工艺可解决传统的酸去锈无法避免的缺陷，具有较好的推广价值。     

气敏传感器的研究现状与发展趋势

传感器技术是现代检测和自动化技术的重要基础之一 ,它已深入到人类生活的各个领域。随着微电脑和微电子技术的日益普及和应用 ,对传感器的性能、数量及用途提出了新的需求 ,这就使人们更加重视对新型传感器的开发。重点介绍气敏传感器的研究现状与发展趋势     

产业部门的用水性质分析

依据可持续发展的思想，以节约资源、保护环境为目标，对我国经济系统的水资源利用状况进行了分析，提出建立高效节水防污的产业调整建议：(1)构建高效节水的生产模式思想；(2)运用水利投入产出分析原理，通过用水与产出效应对我国用水部门的用水效益与效率进行评判；(3)根据水利投入产出分析结果，对部门用水后的水环境影响效应进行分析；(4)综合评价分析，提出资源、环境、经济社会协调发展的产业结构调整建议。