牡丹种间花粉粒形态差异性比较

利用扫描电子显微镜对三种牡丹不同品种的花粉形态进行了观察研究,报道了花粉形态特征和种闻差异,探讨了花粉形态特征在种间演化的分类学意义。结果表明,牡丹属牡丹组成熟花粉粒形态大小和外壁纹饰存在着种间差异。     

超高分子量聚乙烯(UHMWPE)凝胶纤维串晶结构形成机理的研究

超高分子量聚乙烯(UHMWPE)在凝胶纺丝工艺条件下超分子结构的形成及其机理是目前正在研究的热门课题。本文借助扫描电子显微镜(SEM)、广角 X 射线衍射(WAXD)、小角 X 射线(SAXS)和透射电子显微镜(TEM)等手段初步研究和探讨了 UHMWPE 凝胶丝在超拉伸过程中超分子结构的形成过程及机理,发现拉伸后纤维具有明显的串晶结构并有部分向连续结晶体结构转化,而且认为这一超分子特征结构是纤维取得高性能的内在结构原因。     

三维适形放射治疗犬自发性前列腺增生的扫描电镜观察

目的:研究三维适形放射治疗后前列腺增生组织细胞超微结构的变化,探讨三维适形放射治疗的作用。方法：选择7～15岁老年犬自发性BPH模型10只,随机分为2组。应用3-DCRT直接照射前列腺。以90％的等剂量曲线包绕整个前列腺,单次剂量2Gy,总剂量14Gy,应用6MV-X线完成照射。对照射前、照射后1、3月前列腺组织切片扫描射电镜观察,比较照射前、后组织形态学变化。结果：与照射前比较,照射后扫描电镜下可见,前列腺腺体萎缩,腺体之间间距增大,腺细胞脱落形成空洞。平滑肌萎缩,以纤维组织为主,纤维纤细。结论：3-DCRT可以使腺体和间质萎缩从而缩小前列腺体积改善尿路梗阻和下尿路症状。     

电子束聚焦测量电子荷质比的误差分析与研究

当利用电子束的磁聚焦测量电子荷质比时,不同的实验方法,不同的数据处理方法都会得出不同的结果,而这些结果中,大部分偏小于理论值1.759×1011C/kg,本实验通过尝试和比较不同的处理和测量方法,利用找出的最佳方法得出了多组误差在1‰附近的较准确数据.1实验基本原理图1电聚焦电     

磁场中电子绕原子核运动角频率的变化

本文以氢原子为例，讨论并定量计算了在磁场中电子绕原子核运动角频率的变化。     

蝗虫三种触角扫描电镜研究

采用扫描电镜的方法对白膝网翅蝗Ａｒｃｙｐｔｅｒａ ｆｕｓｃａ ａｌｂｏｇｅｎｉｃｕｌａｔａ ｌｋｏｎｎ的丝状触角、条纹鸣蝗Ｍｏｎｇｏｌｏｔｅｔｔｉｘ ｊａｐｏｎｉｃｕｓ ｖｉｔｔａｔｕｓ（Ｕｖ．）的剑状触角及西伯利亚蝗Ｇｏｍｐｈｏｃｅｒｕｓ ｓｉｂｉｒｉｃｕｓ（Ｌ．）的棒状触角表面进行了扫描电镜观察，结果表明三种蝗虫触角不仅在形态上差异显著，而且在感觉器种类组成、分布及化学感觉能力上有明显不同，主     

首次在厦门地区地里纤恙螨体内分离恙虫病立克次体及其微形态观察

１９９２年４～６月在厦门市万石植物公园捕获的黄胸鼠体外采获大量地里纤恙螨，并从该螨分离出一株恙虫病立克次体，在光镜下立克次体呈圆形或椭圆形，其大小为０．４０２～０．７０３×０．５０２～０．９０４（０．５０８×０．６１７）μｍ．在扫描电镜下其形态多为圆球状，细胞内立克次体有一层０．２３μｍ厚的外膜，立克次体大小为０．２１８～０．７６０×０．３９５～１．０９μｍ．     

Structural and biochemical mechanism responsible for the stay-green phenotype in common wheat

In order to increase the supply of assimilated carbon to grain, a new stay-green wheat cultivar, Chuannong17 (CN17), with delayed leaf senescence, carrying wheat-rye 1RS.1BL translo- cated chromosome was developed. CN17 exhibited distinct differences in net photosynthetic rate (Pn), chlorophyll (Chl) content, malondialdehyde (MDA) content, activity of both superoxide dismutase (SOD) and catalase (CAT) during the grain filling stage, and flag leaf senescence compared with the control. The new cultivar maintained longer and higher photosyn- thetic competence compared with the control, and this aspect correlated with the difference in chloro-plast development. Moreover, the stay-green pheno-type of CN17 was also observed under natural growth conditions. Consequently, the coordination of the physiological, biochemical, and structural aspects in the stay-green cultivar produced higher seed weights and per-plant yield compared with the control cultivar.     

On theories of solar type III radio bursts

In solar radiophysics,many theories for type Ⅲ bursts have been proposed during the past 60 years.Almost all these theories are based on the plasma hypothesis,which assumes that(i)the radiation is mainly generated by Langmuir waves via nonlinear processes and(ii)the radiation has frequencies close to the local plasma frequency and/or its second harmonic in the source region. We feel strongly that it is time to advocate an alternative approach without recourse to the plasma hypothesis.This brief discussion explains why.