根瘤菌87-1-1诱导刺槐根表皮传递细胞特异性表达的cDNA文库构建及序列分析

探寻根瘤菌诱导刺槐后根表皮细胞分化成传递细胞的特异性表达基因及其分子机制.采用抑制差减杂交(suppression subtraction hybridization,SSH)技术构建刺槐根系被接种根瘤菌和未被接种根瘤菌二者间的正反两个c DNA文库.各挑选正反文库中500个克隆进行测序,在Blastn、Blastp、Swiss Prot、KEGG、COG、Interpro以及Gene ontology(GO)数据库中进行比对注释.结合生理过程对ESTs进行分析,共获得725条非冗余序列(uni EST),正反向文库分别为385条和340条,其中包括674个单一序列(singlets),51个拼接序列(contigs).在Nt库比对中有674条uni ESTs与已知基因匹配,占比93%;在Nr库比对中有648条序列有匹配蛋白,占比89%.有正向文库213个uni ESTs和反向文库156个uni ESTs能进行Geney ontology(GO)功能注释,在细胞组分被注释了270次,分子功能被注释了448次,生物过程被注释了484次.uni ESTs的功能分析显示,正向文库中多与细胞翻译后修饰、转录因子、细胞信号通路、细胞壁/细胞膜/内膜系统以及细胞骨架相关蛋白有关,部分是结瘤相关基因.而反向文库中与细胞生长、代谢物形成的基因相关较多,这与根瘤菌处理刺槐后的生理过程一致.在根瘤菌诱导的刺槐根组织文库中发现特异性基因如MYB类转录因子、囊泡相关膜蛋白等与传递细胞相关的基因,结果有助于进一步研究此类传递细胞的形成分化机制.     

基于气泡的缸盖水腔沸腾传热仿真研究

从气泡核化条件及沸腾起始点要求出发,提出相变判定条件,从而准确界定沸腾区域. 基于沸腾均相流计算模型框架,建立了沸腾传热数值计算模型,并利用Robinson实验数据对该计算模型的准确性进行了校核. 利用该数值模型对缸盖温度场进行了预测,与实机测温结果进行实验比对,证明新沸腾数值模型计算结果更接近实机测试温度,火力面测点最大误差不超过7%.      

制冷剂侧结构对多元微通道平行流冷凝器传热与流动性能的影响

建立了多元微通道平行流冷凝器的稳态分布参数模型,将模型计算值与其实验结果对比验证了模型的正确性.同时,利用所建立的模型研究了扁管孔数、扁管内孔高宽比、流程布置、各流程间扁管数分配方式等参数对平行流冷凝器传热和流动性能的影响.结果表明:随着扁管孔数的增多,换热量逐渐增大,制冷剂侧压降逐渐减小,空气侧压降逐渐增大;随着扁管内孔高宽比的增大,换热量与制冷剂侧压降逐渐减小,空气侧压降不变;随着流程数的增多,换热量与制冷剂侧压降逐渐增大;当流程数一定时,各流程间扁管数的分配宜从第1流程向后依次递减,其递减速率逐渐减小,且过冷区的扁管数不宜过少.     

一种适用于柴油机结构温度场计算的缸内传热模型

基于量纲分析式h(Ф,i)=C(Ф)d-0.2 p0.8 w0.8 T-0.8μ-0.47eλ0.67ec0.33p分析了柴油机的缸内三维局部传热情况,其特征参数选取缸内瞬态流动传热参数,并通过Woschni模型计算传热总量,在每个曲轴转角条件下,保证局部传热计算中对全部壁面网格热流求和所得传热总量与Woschni模型的计算值相等,以确定待定系数C(Ф).同时,将改进的缸内传热模型应用于一款单缸水冷自然吸气式四冲程直喷柴油机的缸内传热计算,所得模拟结果与实验结果吻合.     

全玻璃真空管太阳能水蒸气集热系统实验研究

设计了一种使用全真空玻璃集热管、简化CPC(非追踪式复合抛物线聚光板)集热板和金属换热套管组合的中温太阳能水蒸气集热系统.系统由60个集热单元串联而成,每个集热单元包括简化CPC集热板、全真空玻璃集热管和换热套管三部分,在全真空玻璃集热管和换热套管之间填充了一种高导热性能固液混合型导热介质增强其导热性能.研究了系统的集热性能和天气条件、集热单元级数等不同工况对系统集热性能的影响.实验结果表明:该系统能够获得200℃的高温蒸汽,集热效率达到0.332,表现出优异的集热性能,是一种有工业应用前景的太阳能水蒸气集热器,为将该高温太阳能集热器用于更广阔的领域提供了设计基础.     

基于知识转移的图书馆虚拟参考咨询服务研究

阐释了图书馆虚拟参考咨询服务的实质,分析了图书馆虚拟参考咨询实现知识转移的影响因素,探讨了基于知识转移的图书馆虚拟参考咨询服务策略。     

基于传递函数和指端脉搏波的桡动脉脉搏波重建

桡动脉脉搏波的检测方法易受人体运动影响,因此提出了传递函数法通过指端脉搏波来估计桡动脉脉搏波.首先,通过分析窗宽和模型阶次建立指端脉搏波到桡动脉脉搏波的传递函数FIR模型;然后,使用测试数据评估模型对桡动脉脉搏波估计的精度.通过对10个受试者10d的样本数据进行分析处理,发现估计的桡动脉脉搏波与实测的桡动脉脉搏波最佳波形匹配度均在70%至92%范围内.结果表明使用传递函数法可以实现对桡动脉脉搏波的初步估计,该方法的提出为桡动脉脉搏波的检测提供了一种更简便的手段.     

Constructal entransy optimizations for insulation layer of steel rolling reheating furnace wall with convective and radiative boundary conditions

Based on the entransy dissipation extremum principle for thermal insulation process, the constructal optimizations for a plane insulation layer of the steel rolling reheating furnace wall with convective and radiative boundary conditions are carried out by taking the minimization of entransy dissipation rate as optimization objective. The optimal construct of the plane insulation layer is obtained. The results show that for the convective heat transfer boundary condition, the optimal constructs of the insulation layer obtained based on the minimizations of the entransy dissipation rate and heat loss rate are obvi- ously different. Comparing the optimal construct obtained based on the minimization of the entransy dissipation rate with that based on the minimization of the heat loss rate, the entransy dissipation rate is reduced by 5.98 %, which makes the global thermal insulation performance of the insulation layer improve. For the combined convective and radiative heat transfer boundary condition, compared the insulation layer having an increasing thickness with that having constant thickness and a decreasing thickness, the entransy dissipation rates are reduced by 16.59 % and 39.72 %, respectively, and the global thermal insulation performance of the insulation layer is greatly improved.There exits an optimal constant coefficient α2,opt which leads to the minimum dimensionless entransy dissipation rate of the insulation layer. The difference between the optimal constant coefficients α2,opt obtained based on the minimizations of the entransy dissipation rate and the maximum temperature gradient of the insulation layer is small. This makes the corresponding thermal stress obtained based on the minimum dimensionless entransy dissipation rate also be small, and the global thermal insulation performance and thermal safety of the insulation layer are improved simultaneously. The results obtained can provide some guidelines for the optimal designs of the insulation layers.     

Acid condensation and heat transfer characteristics on H-type fin surface with bleeding dimples and longitudinal vortex generators

Acid condensation rate is an important factor denoting the acid corrosion, and the reduction of the acid condensation can significantly relieve the acid corrosive effect on the wall surface and improve the security of the equipments. In this study, the characteristics of both heat transfer and acid condensation of the finned tube in heat exchanger were numerically studied. In the numerical model, we simulated the acid condensation by considering the vapor-liquid equilibrium effect and multi-component diffusion effect. Based on the H-type finned oval tube, we proposed three novel types of fins to both enhance the heat transfer and reduce the acid condensation. The parametric effects of gas temperature, acid vapor concentration, water vapor concentration, and Reynolds number were investi- gated on different fin structures. The results show that the tube bank with the new structured fins can improve the performance on both heat transfer and acid anticondensation.     

不同电极结构下电场对甲烷/空气火焰的影响

基于电场促进燃烧的理论,为了进一步研究不同电极结构对燃烧的影响,利用定容燃烧弹来模拟发动机气缸内的燃烧,在常温常压不同当量比(0.8、1.0和1.2)下通过分别加载3种不同结构的电极对直流电场与甲烷/空气火焰的关系进行了研究。结果表明:3种电极结构下电场对火焰横向传播均有明显的促进作用,且网状电极下火焰横向传播的促进效果最明显,然后依次是柱状电极和点电极;3种电极结构下燃烧压力一开始均得到不同程度的提高,而网状电极下电场对燃烧压力的影响最为明显。综上所述:3种电极结构中,网状电极下电场对火焰的促进作用最大,在今后的应用中较其他两种电极有更为明显的优势。