植物基因克隆的方法和策略

芬子生物学的迅速发展对克隆植物基因起了积极的推作用，本篇旨在介绍植物基因克的策略及研究进展。     

几个重要的概念的正反叙述及应用

在微积分学中,经常会遇到一些重要概念的定义,如极限的定义,函数在一个集合上的一致连定续性的义,级数或广义积分的一致收敛性定义等,为了更好地掌握这些概念以及更好地利用这些概念去得到一些新的结果、新的命题,往往需要从反面来了解这些概念,还样才能对这些概念有更深入的理解。本文就在这一方面作一些介绍。     

球状星团中荷磁黑洞附近星的投影密度分布的计算

本文用广义相对论讨论了球状星团中荷磁黑洞附近星的投影密度分布,得到(dN/dΩ)_(q_m)<(dN/dΩ)_s,即在中心是荷磁黑洞的球状星团中每单位立体角的星数少于中心是Schwarzschild黑洞的星数。     

论逆向思维在地球概论教学中的运用

根据多年教学实践，论述了在地球概论教学中，逆向思维程序的设计，以及动用逆向思维思考问题时，可采用的创造技法．并且归纳出逆向思维对地球概论常规教法的辅助作用．     

IDX法测定湿地松种子生活力的研究

以水作衬比剂，对湿地松（Ｐｉｎｕｓ ｅｌｌｉｏｔｔｉ Ｅｎｇｅｌｍ）种子进行ＩＤＸ法检验其生活力的研究，结果表明：湿地松种子在２５℃水中浸２ｈ后，置床培养４８ｈ，用吸水纸吸去表面水份，用硅胶干燥９ｈ（３０℃），其Ｘ射线片上死活种子图像差异显著，其判读结果与发芽率基本一致。     

谈排球规则的修改对技战术的影响

根据排球规则修改的内容，提出了将会出现的队员发球位置改变，脚踢球的现象，软式传球的合法化，以及新的战术配合等技术和战术。新规则使排球运动攻守更趋于平衡。     

Structure characterization of melt drawn polyethylene ultrathin films

Highly oriented ultrathin polyethylene (PE) films were prepared by a melt-draw technique. Transmission electron microscopy study on the obtained ultrathin films indicates that the melt drawn PE thin films consist of highly oriented edge-on lamellae aligned perpendicular to the drawing direction. Electron diffraction confirms that the PE chains in crystal-line phase are highly oriented in film plane along the drawing direction, while only a random orientation of the crystallographic a-and b-axes can be described through electron diffraction. The IR results on the melt-drawn ultrathin PE films demonstrate that the PE molecular chains in both crystalline and amorphous phases of the melt drawn thin films are well oriented along the drawing direction. Moreover, the IR results indicate that in the crystalline phase, the crystallographic b-axis tend to lie in the thin film plane, while in the amorphous phase, the skeleton plane of some local chains prefers to parallel the film plane. The alignment of b-axis of PE crystals in ultrathin films originates from the fact that the b-axis is the fastest growth direction of the PE crystals.     

A new improved structure of dye-sensitized solar cells with reflection film

DYE-SENSITIZED NANOCRYSTALLINE SOLAR CELLS (DSSC), RECENTLY DEVELOPED BY MICHAEL GR?TZEL[1], HAVE BEEN ATTRACTING CONSIDERABLE ATTENTIONS BECAUSE OF ITS HIGH EFFICIENCY, SIMPLE FABRICATION PROCESS AND LOW FABRICA- TION COST[2]. TYPICAL DSSC[3] IS BASED ON A SANDWICH STRUCTURE, WHICH CONSISTS OF TWO GLASS PLATES WITH A TRANSPARENT CONDUCTING OXIDE (TCO) COATING AS SUBSTRATE. O…     

低信噪比图像中运动点目标的检测方法

图像中点目标的检测是目前比较活跃的研究领域,它在制导、天文观测、遥感等学科中有着重要的应用价值。在低信噪比条件下,要从图像中检测出运动的点目标存在着不少困难。本文首先分析了低信噪比情况下检测的难点,然后对目前七种有代表性的方法加以评介。