混凝土中氯离子传输模拟及速率分析

为模拟氯离子在混凝土中传输规律,基于Fick第二定律和Darcy定律建立氯离子扩散-对流模型,同时考虑温湿度、孔隙率、结合效应等多种影响因素对扩散系数进行修正,利用Matlab和COMSOL Multiphysics实现多场耦合数值模拟,最终结合试验数据模拟氯离子传输过程.结果表明:数值模拟与实验结果相关性良好,能有效...     

离子注入介质中输运的数值模拟

讨论了离子注入在人质中输运的数值模拟方法，采用扩散理论和交替方向隐式的Ｄ－Ｒ差分法，以砷离子注入在硅单晶中输运为例，数值模拟结果与实验结果基本相符。     

活体细胞图像斑点的自动提取和跟踪方法

采用基于小波分解多尺度系数乘积的方法检测图像中的斑点,同时提出了基于贪婪思想的可以自动处理目标分裂和合并的模型,综合目标信息对轨迹进行跟踪.对Adaptor和Clathrin图像分割取得了比较理想的结果,Adaptor图像中的目标识别率98.61%,Clathrin图像中目标识别率达到97.65%.新的跟踪算法在处理轨迹合并和分裂方面有明显优势,对斑点跟踪效率达到为98.05%.结果表明,新的算法能有效地识别和跟踪图像中的斑点.从生物学角度,更有效的识别有助于更好地理解质膜的通道运输机制以及因为其不正常工作引起的疾病.     

基于Visual C++的伪随机数发生器及其在离子输运模拟中的应用

叙述了产生伪随机数的原理及采用VisualC＋＋语言获得伪随机数发生器的方法。在模拟微波离子源强流中子管的引出系统的光学特性的过程中，采用了这个发生器，并对其产生的结果进行了检验，获得了满意的结果。     

环境条件和应力水平对混凝土中氯离子传输的影响

为了研究自然环境中混凝土的氯盐侵蚀过程,进行了不同侵蚀角度、氯化钠溶液质量浓度、环境温度、应力水平下的混凝土盐雾加速侵蚀试验,分别探讨了在不同的条件下氯离子在混凝土中的扩散规律.结果表明:盐雾箱中试件放置角度不同,其表面氯离子聚集量会不同,最终导致氯离子侵蚀程度不同,其中以平面或45°侧面为侵蚀面时,表面氯离子质量分数较高,氯离子侵蚀程度严重;随着氯化钠溶液质量浓度的增大,盐雾沉降量增加,表面氯离子质量分数也增加,不过最终会达到一个衡定值;随着环境温度的升高,氯离子表观扩散系数逐渐增大;由于压应力状态下混凝土内部结构更加密实,氯离子表观扩散系数显著减小.     

拟南芥中一个镍离子转运蛋白的亚细胞定位

离子的跨膜转运是细胞获取养分的重要环节,亦是植物在组织和器官水平上进行养分吸收运移的基础．在植物中镍（Ni）元素主要以Ni^2＋的形式存在,并通过Ni^2＋转运蛋白将其跨膜转运至相应的组织器官,参与氢酶和脲酶的合成．生物信息学分析表明,拟南芥中一个Ni^2＋转运蛋白AT2G16800含有叶绿体定位信息．克隆该基因5’端编码转运肽的272bp片段,与绿色荧光蛋白（GFP）基因融合后,在拟南芥中高效表达,对其进行了亚细胞定位的研究．转基因植株通过共聚焦扫描显微镜的观察,发现GFP荧光信号只存在于叶绿体中,该结果表明A他G16800为叶绿体蛋白．     

'Coatomer': a cytosolic protein complex containing subunits of non-clathrin-coated Golgi transport vesicles

Golgi-derived coated vesicles contain a set of coat proteins of relative molecular mass 160,000 (Mr 160K; alpha-COP), 110K (beta-COP), 98K (gamma-COP) and 61K (delta-COP), and several smaller subunits. We have now identified and purified a cytosolic complex containing the same four coat proteins as those of Golgi transport vesicles. We term this complex the Golgi coat promoter or 'coatomer'. The coatomer also contains polypeptides of Mr 36K, 35K and 20K. It represents about 0.2% of soluble cytosolic protein. Gel filtration of unfractionated cytosol indicates that beta-COP resides exclusively in the coatomer complex. The complex seems to be a likely candidate for the unassembled precursor of Golgi coated vesicles, and its purification should help investigations of the role of coat proteins in membrane budding, for which it is necessary to use a refined cell-free system.     

Immuno-isolation of Sec7p-coated transport vesicles from the yeast secretory pathway.

The transport of proteins destined for post-endoplasmic reticulum locations in the secretory pathway is mediated by small vesicular carriers. Transport vesicles have been generated in cell-free assays from the yeast Saccharomyces cerevisiae, and mammalian systems. Yeast genes encoding cytosolic components that participate in vesicular traffic were first identified from the collection of conditional-lethal sec-(secretory) mutants. Mutations in the yeast SEC7 gene disrupt protein transport in the secretory pathway at the nonpermissive temperature. The SEC7 gene product is a phosphoprotein of relative molecular mass 230,000 that functions from the cytoplasmic aspect of intracellular membranes. We report that in a yeast cell-free transport assay, the introduction of antibodies to Sec7 protein (Sec7p) results in the accumulation of transport vesicles. These vesicles are retrieved with Sec7p-specific antibodies by immuno-isolation for biochemical and electron microscopic characterization. Sec7p on the surface of the accumulated transport vesicles, in combination with previous genetic and biochemical studies, implicate Sec7p as part of a (non-clathrin) vesicle coat. This Sec7p-containing coat structure is proposed to be essential for vesicle budding at multiple stages in the yeast secretory pathway.