百合小孢子母细胞形成和发育过程中细胞间连接形态和结构的变化

超显微结构水平观察发现造孢时期细胞的壁较厚，由中间层，初生和次生壁组成，细胞间的连接为典型的细胞间连丝，减数分裂前间期的细胞壁主要由中间和初生壁组成，典型的胞间连丝消失，但局部位置上的中间层和初生壁组分缺失，构成约２００～８００ｎｍ，宽的“豁口”，进入分裂期后，次生壁组分急剧增加，当整个细胞壁加厚到２４０－５００ｎｍ时，细胞壁出现穿孔，穿孔过程似乎有下列两种方式：１）在细胞壁的一侧或两侧出现电子致     

冬枣果实韧皮部及其周围薄壁细胞的超微结构观察和功能分析

利用透射电镜技术,对发育过程中的冬枣果实韧皮部及周围薄壁细胞的超微结构进行了观察研究。结果表明,果实发育早期筛管伴胞复合体与周围薄壁细胞之间存在少量胞间连丝,发育中期胞间连丝数量有所增加,筛分子和伴胞间及韧皮薄壁细胞问存在丰富的胞间连丝,显示了从筛管伴胞复合体卸出到周围薄壁细胞的同化物的卸载路径可能发生了变化。果实发育的各个时期伴胞胞质致密,富含线粒体、内质网和高尔基体,液泡化程度不等;果实发育前期,筛分子伴胞复合体与邻近的薄壁细胞质膜存在囊泡结构,果实韧皮部薄壁细胞胞质中含有丰富的线粒体、内质网、高尔基体、多泡体和小囊泡,到后期线粒体开始降解,显示了伴随果实发育薄壁细胞内的物质代谢和运转功能经历了由活跃到下降的过程。     

不同品质类型小麦籽粒结构的观察比较

应用扫描电子显微镜观察了3个不同品质类型的小麦品种（强筋小麦济南17号、中筋小麦扬麦12号和弱筋小麦扬麦9号）的籽粒断面结构。结果表明,济南17号胚乳舍有丰富的基质蛋白质,淀粉粒被包埋在基质蛋白质中间,胚乳结构致密;扬麦12号胚乳淀粉粒与基质蛋白质所连接,胚乳结构较疏松;扬麦9号胚乳蛋白质基质含量很少．淀粉粒与蛋白质结合不紧密。采用碱处理和差速沉淀法分离了籽粒胚乳大、小淀粉粒,扫描电镜观察发现品种间淀粉粒的形态无明显差别,但大、小淀粉粒的尺寸和含量在品种间存在很大差异。     

烟草叶片组织结构的扫描电镜观察方法

将烟草叶片经过固定、水解、剥离、降解、浸泡、置换、干燥、喷金等处理 ,成功地制备出了烟草叶片各层组织的扫描电镜样品 ;首次获得烟草叶片各组织层的立体结构图像 ,通过比较 ,发现不同部位叶片内部组织结构存在某些规律差异。为研究烟草叶片各组织层中细胞分布和生长发育规律提供了一条新的途径。     

水稻不同品种叶表面硅质细胞的扫描电镜观察

应用扫描电子显微镜对8个不同品种的水稻（Oryza sativa L.）叶片表面硅质细胞的形态结构进行了观察,并首次用X射线能谱分析其硅含量.结果发现8个品种间叶片表面硅质细胞形态结构和硅元素含量差异明显,四倍体品种不但硅质细胞大,而且硅元素含量也较高,其中矮脚南特-4x叶片表面硅质细胞表面积最大,达301.40mm^2,硅元素相对含量也最高,为32.77 wt.%;广陆矮4号-4x硅质细胞表面积次之,为192.50mm^2,硅元素相对含量为25.80 wt.%.这2个四倍体品种的气孔硅乳突数都是8个,比二倍体品种多1倍.四倍体品种田间表现植株直立、基部通风性好、抗倒伏能力和抗病虫性均较强.二倍体品种零轮、P23、L202、D27 F2（野生稻杂种）、华粳籼74和E5等品种硅质细胞表面积明显比四倍体的小,平均小3.6倍;硅元素含量也较低,平均比四倍体的低1.4倍;抗性较2个四倍体水稻品种差.本文的结果初步说明水稻叶片硅质细胞大小和含量与抗性可能存在密切的相关.     

未来巡航导弹发展趋势及其防御策略

随着我国经济的不断发展,国家地位慢慢的到提高,增强我国的国防实力势在必行,是我国的重要的国策,巡航导弹在战争中占据着重要的地位,主要是实施远程打击,在大气层中巡航的导弹,从近几年的战争形势来考虑,巡航导弹的作用越来越明显,在战争中起着战略和战术作用,巡航导弹主要对地方的重要基地进行远程打击,既能起到精确打击的作用,又能整体上提升战斗力。各个国家对于巡航导弹的研究力度不断加大,本文谈一谈未来巡航导弹的发展趋势,以及对于巡航导弹的防御策略。     

High performance platinum nanofibers with interconnecting structure using in dye-sensitized solar cells

Platinum nanofibers (PtNFs) with interconnecting structure are prepared by a simple electrospun method and novel film forming technique, which are used as the counter electrode (CE) materials for the dye-sensitized solar cells (DSSCs). Electron microscope images demonstrate that PtNFs are constituted by Pt nanoparticles. Cyclic voltammetry measurements indicate that PtNF CE has an excellent catalytic activity for the reduction of triiodide to iodide. DSSC based on PtNF CE achieves an enhanced photovoltaic conversion efficiency of 9.31% compared to that of DSSC based on Pt CE (7.32%) prepared by the thermal decomposition, owing to the three-dimensional interconnecting nanostructure has abundant catalytic surfaces, large contact area with the electrolyte, and lots of electronic transmission channels. DSSC efficiency based on PtNF CE remains 90.08% after continuous scanning 1000 s under an open system without any sealing in ambient atmosphere, and 83.19% of the efficiency is remained after 1000 h under a strictly packaging for the device application.     

Influence of compact TiO2 layer on the photovoltaic characteristics of the organometal halide perovskite-based solar cells

A series of perovskite-based solar cells were fabricated wherein a compact layer (CL) of TiO₂ of varying thickness (0–390 nm) was introduced by spray pyrolysis deposition between fluorine-doped tin oxide (FTO) electrode and TiO₂ nanoparticle layer in perovskite-based solar cells. Investigations of the CL thickness-dependent current density–voltage (J–V) characteristics, dark current, and open circuit voltage (V_oc) decays showed a similar trend for thickness dependence. A CL thickness of 90 nm afforded the perovskite-based solar cell with the maximum power conversion efficiency (η, 3.17%). Furthermore, two additional devices, perovskite-based solar cell omitting hole transporting materials layer and cell without the TiO₂ nanoparticles, were designed and fabricated to study the influence of the CL thickness on different electron transport paths in perovskite-based solar cells. Solar cells devoid of TiO₂ nanoparticles, but with perovskite and organic hole-transport materials (HTMs), exhibited sustained improvement in photovoltaic performances with increase in the thickness of CL, which is in contrast to the behavior of classical perovskite-based solar cell and common solid state solar cell which showed optimal photovoltaic performances when the thickness of CL is 90 nm. These observations suggested that TiO₂ nanoparticles play a significant role in electron transport in perovskite-based solar cells.     

Fabrication process not limited by the lithography resolution of lateral phase change memory

To improve the performance of phase change memory (PCM) and reduce the cost of fabrication, we propose a new lateral PCM structure based on the technology of angle evaporation to define the critical dimension controllable, not limited by the limitation of lithography resolution. The fabrication process is cost-effective. PCM cells featured 80 nm×100 nm were successfully demonstrated, although the resolution of the aligned used was 1 µm only. Compared with the traditional lateral PCM structure, finite element simulation results show that the new structure has better thermal stability.     

AFM观察稳恒磁场对细胞表面精细结构的影响

利用原子力显微镜(AFM)观察稳恒磁场(SMF)处理后,悬浮生长细胞(K562人白血病细胞)、贴壁生长细胞(人结肠癌SW480细胞)、小鼠肝癌细胞Hepal-6和原代小鼠肝细胞表面精细结构的变化,以了解SMF杀伤肿瘤细胞的可能机制.观察结果显示:随曝磁时间延长,SMF可在肿瘤细胞表面造成不同程度损伤,主要表现为细胞膜上出现许多大小不一的凹陷,且凹陷数量和直径随着曝磁时间延长而增加.与MTT检测相比,AFM观察到的各类细胞表面损伤远早于细胞的生长抑制.实验观察显示,悬浮生长细胞比贴壁生长细胞对磁场处理更为敏感,小鼠肝癌细胞比肝细胞对磁处理更敏感.实验结果显示,AFM能够及早观察到细胞表面因SMF作用而产生的精细结构方面的变化.     

He－Ne激光对小麦属间杂交影响的研究

１９８８～１９９２年，作者采用Ｈｅ－Ｎｅ激光辐照黑麦花粉与杂交相结合的方法，对小麦属间杂交（普通小麦×黑麦）进行了研究。属间杂交所获种子的结实率极显著高于对照，为１１３．２５～３４１．６０％。籽粒千粒重和饱满度均超过对照，差异极显著。Ｌ＿１代籽粒出苗率和植株成活率分别比对照提高５８．１８～８３．０６％，４１．３５～８７．７８％，差异均超过极显著水平。Ｌ＿１代种子、植株和穗的大多数形态特征呈中间型或似父本，其余特点象母本。在Ｌ＿１代植株中均获得了染色体自然加倍的双二倍体，即小黑麦种子。现已获得了Ｌ＿１、Ｌ＿２、Ｌ＿３和Ｌ＿４代的小黑麦后代材料。Ｈｅ－Ｎｅ激光诱变小麦属间杂交，使杂种染色体自然加倍，为小麦属间杂交育种工作提供了新的简便途径。