荷电喷雾两相湍流流场的数值计算

荷电喷雾可以有效地改善雾化质量和喷雾流场特性，因此被广泛地应用于静电喷涂、除尘、药物喷洒和液体燃料的雾化燃烧等领域．荷电喷雾湍流射流流场的数值模拟对于荷电喷雾装置的设计及确定射流喷雾的各特性参数具有重要意义、采用颗粒拟流体方法，用κ-ε-κp荷电两相湍流模型对荷电喷雾气液两相湍流流场进行了数值模拟．经与实验结果对比，该模型可以较好地模拟荷电气液两相湍流射流流场，可用于荷电喷洒机具和荷电喷雾燃烧器的设计。     

含时线性势非线性薛定谔方程的孤子解

考虑含时线性势非线性薛定谔方程，通过Darhoux变换给出该方程的N-孤子解，由此得到一孤子解和二孤子解的精确表达形式，并讨论孤子解的性质和相互作用．     

高校体育为社区体育支持服务的机制研究

研究探讨高校体育与社区体育之间的互动关系 ,旨在发挥高校体育人才集中和良好的场地设施及指导优势 ,为推进全民健身计划二期工程提供可行性研究 .体育是我国开展全民健身活动的重要组成成分 ,高校体育在人才培养、场地设施、服务管理等方面具有很大的优势 ,应充分发挥高校体育的优势作用 ,为我国城市社区体育的开展做出应有的贡献 .树立社区体育服务意识 ,在完成教学工作的同时 ,开发潜能更好发挥高校体育的社会功能 ,寻找一条有中国特色的高校体育与社区体育共同发展之路     

无伸缩缝桥梁的地震响应研究

以福建省永春县上坂大桥为工程背景，针对无伸缩缝桥梁的结构特点，提出一个土～结构的非线性相互作用模型。在此基础上建立有限元模型，采用谱分析法和时程分析法研究该桥的地震响应，研究结果可为无伸缩缝桥梁的抗震设计提供理论依据。     

转子在静电支承系统中的转速衰减特性

高真空静电支承式旋转系统中,偏心转子在磁场和静电力矩作用下,产生转速衰减,从而降低了系统精度。该文建立了静电力矩的数学模型,确定了支承系统频率特性与静电力矩大小之间的关系。在此基础上设计了含陷波滤波器、带宽相对较低的支承系统,以改善其局部频率特性,消除静电力矩引起的转速衰减。实验给出了常规和改进支承系统的转速测量结果,并进行了比较,从中分离出静电力矩的大小。结果表明,通过改变支承控制系统局部频率特性,可以消除静电降速力矩,最终提高了转子转速的长期稳定性。     

数字黑板系统的研究与实现

在教学过程中教师通常只能使用计算机和数字投影机“展示”事先准备好的电子教案和电子素材,无法进行有效的互动和板书;互动式电子白板虽然可以实现黑板功能,但是受到工作区尺寸的限制,无法在常规教学中广泛使用。针对上述问题,基于人机交互中的笔交互技术、Agent技术,设计并实现了一个数字黑板系统,并将线框几何模型技术和图形约束技术应用其中。系统工作时,使用投影机投影做大尺寸黑板板面,有效地解决了问题。该系统不仅实现了互动式电子白板的功能,同时也实现了一些附加的功能,如在计算机屏幕上直接进行标注和突出显示、黑板视窗、辅助绘图等功能,具有较好的应用前景。     

乙酰苯胺类化合物的QSAR研究

利用量子化学程序计算了17个乙酰苯胺化合物的量子化学参数（如最高占据轨道能级、最低空轨道能级、极化率、杂原子静电荷、偶极矩等），并对化合物的最小阻滞浓度（MBC）进行了定量结构-活性相关（QSARs）分析，其中最高占据轨道能级、极化率、N（3）原子静电荷3个参数共同构建的模型准确性最高（R=0．907，F-20．064）．该模型说明化合物毒性与脂溶性关系不大，而是可能通过与受体间提供电子发挥效应，且N（3）原子为作用位点．同时利用该模型对MBC进行了理论预测，结果表明该模型能很好地预测化合物的MBC，预测值与实验值误差较小．     

水稻DH群体剑叶宽度的QTL及其上位性和环境互作效应研究

利用基于混合模型的QTL定位方法,可以分析水稻DH群体在4个年份下剑叶宽度的QTL及其上位性效应和环境互作效应.结果发现,QTL除了具有自身的效应外,还可以参与上位性效应的形成,一个QTL可与多个QTL发生互作,可能起到诱发和修饰其他位点的作用.QTL与环境的互作效应以及上位性与环境的互作效应更多地被检测到,表明控制剑叶宽度的遗传因素易受环境影响.     

Development and differentiation of the intestinal epithelium

The gastrointestinal tract develops from a simple tube to a complex organ with patterns of differentiation along four axes of asymmetry. The organ is composed of all three germ layers signaling to each other during development to form the adult structure. The gut epithelium is a constitutively developing tissue, constantly differentiating from a stem cell in a progenitor pool throughout the life of the organism. Signals from the adjacent mesoderm and between epithelial cells are required for normal orderly development/differentiation, homeostasis, and apoptosis. Embryonically important patterning factors are used during adult stages for these processes. Such critical pathways as the hedgehog, bone morphogenetic protein, Notch, Sox, and Wnt systems are used both in embryologic and adult times of gut development. We focus on and review the roles of these factors in gut epithelial cell development and differentiation.Received 18 October 2002; received after revision 18 December 2002; accepted 18 December 2002     

Present status and development on biological nitrogen fixation research in China

This presentation introduces the advances in biological nitrogen fixation research abroad, in particular,describes the great progress and achievements on its research in China as follows: collection of rhizobial resources and establishment of the largest database of Rhizobium in China, correction and development of Rhizobium taxonomy in international; discovery of a couple of nif genes, identification and unification of linkage among the nif gene operons of Klebsiella pneumoniae, finding of regulative mechanism of positive regulation nif gene and its sensitivity to oxygen,temperature; finding of the activity of nodulation gene nodD3 product in Sinorhizobium meliloti which is not controlled by flavonoid produced from its host alfalfa; finding of the association between expression of genes coding the products for carbon utilization and nitrogen metabolism and their regulations; chemical synthesis of nodulation factor of Sinorhizobium meliloti; constructions of engineered nitrogen fixers and utilization in practice based on the research of gene expression and regulation; chemical simulation of the structure and function of nitrogenase and bringing forward the model of nitrogenase active center for the first time in international and synthesis of model compounds which were paid attention by colleagues abroad. Finally, the development of nitrogen fixation research in China in future has been put forward, suggesting that the nif gene regulation and its role in providing crops with nitrogen element, signal transduction and molecular interactions between Rhizobium and legume, coupling between carbon and nitrogen metabolisms, nitrogen fixation and photosynthesis, and functional genomics of nitrogen-fixing nodule symbiosis, etc., would be actively worked on.