非极性共轭分子电子光谱的溶剂效应——蒽在各种溶剂中的紫外吸收光谱

Kundt找出溶质分子的吸收谱带随溶剂色散率的增加而向长波移动的规则,可用下式表示: △v=v_(气体)-v_(溶液)=K_1(n-1)(1) 其中n为溶剂的折光指数.许多学者曾争论这规则的正确性,甚至予以全部否定.经多年研究后,人们才对溶剂与溶质分子间的作用有较全面的了解,才认识只有在溶质分子是非极性,而且在它们与溶剂分子之间又无氢键的情况下,则它们的谱带位移△v才有可能完全决定于溶质-溶剂分子间的色散作用.     

ACHT促使次生胞间连丝和胞间通道的形成

在应用人工促使不同细胞间细胞质和染色质穿壁转移技术的共培养期间,烟草和菠菜细胞间形成厚薄不均匀的隔离层,逐渐被吸收、变薄、直至消失,使不同的细胞直接联结嵌合在一起;在继续共培养时,相邻细胞壁上,从一侧或两侧形成次生半胞间连丝、胞间连丝和胞间通道(细胞融合道),从而把不同细胞联结成共质细胞团,为进一步适时地操作细胞质和染色质的穿壁转移提供了细胞结构和细胞生理基础。本文描述了细胞间各种类型的联结和通道。     

Cu_xS／PAN导电纤维的结构与性能

通过简易的化学反应，将导电性颗粒Ｃｕ＿ｘＳ引入到聚丙烯腈（ＰＡＮ）纤维中，可使其体积电阻率ρｖ达０．０８Ω·ｃｍ～０．１Ω·ｃｍ．通过Ｖ－Ｉ特性、电阻与温度的关系以及ＳＥＭ、Ｘ光及ＸＰＳ等，对导电纤维的导电机理和微结构进行了研究．     

生态文明经济诠释

文章阐释了生态文明经济的内涵、功能以及对生态文明经济的辨别,分析了生态文明经济的表现形态及各种生态文明经济发展形态的联系与区别,说明生态文明经济是社会经济发展的必然趋势。     

INTRODUCTION, EXPRESSION AND REGENE-RATION OF THE TiT-DNA GENES IN CULTURED CELLS FROM Hyoscyamus muticus +Nicotiana tabacum SOMATIC HYBRIDS

After the cultured cells from Hyoscyamus muticus + Nicotiana tabacum somatic hybridswere cocultivated with different virulent strains of Agrobacterium tumefaciens harboringoctopine- type Ti plasmid or nopaline- type Ti plasmid using the transformation procedurein vitro developed in the present investigation, the TiT- DNA genes were introducedinto the host cells. The onc genes and ocs or nos genes located on TiT- DNA were expres-sed in transformed colonies derived from the cocultivated cells. Although the platingefficiencies of recipient cells were reduced by the agrobacterial treatment, the frequenciesof phytohormone autotrophy ranged from 33.9 to 76 .8% in the cells infected with viru-lent strains in hormone- free conditions, and the frequencies of opine synthase activityamounted to 9.7- 47 .5%. Teratomatous shoots were regenerated from the transformed col-onies. During the course of culture the shoots were no longer to lengthen when theygrew up to 1 -3 cm in length, and they could not be rooted. Follo     

STUDY ON WAYS OF FORCING INTERCELLULAR CYTOPLASM AND CHROMATIN MIGRATION TO TRANSFER EXTERNAL GENETIC SUBSTANCES TO PLANT CELLS BY ARTIFICIAL MOTIVE FORCE

A new cell engineering technique (L. B. technique) was established in our Lab. At first, the physical and chemical methods were used to facilitate the reestablishment of intercellular contacts and plasmodesma channels between different parents, thus forcing cytoplasm and chromatin to pass the cell wall with different qualities and quantities from one cell to others, through the enlarged intercellular plasmodesma channels or the vulnerable regions and the holes on the cell wall formed differently in growth and thickness in the process of cell wall formation to introduce external genetic substances or gene groups into plant cells. There are different ways, frequencies and strengths for the migration between the cells in different growth and development regions or the same growth and development region. In this paper we advance the mechanism of cytoplasm and chromatin migration through the cell wall: There are a large number of plasmodesma channels or vulnerable regions and holes different in growth and th     

大柔性飞机着陆响应弹性机体模型

对大展弦比、小弦长差、细窄机身结构特征的飞机,建立了着陆撞击分析时的自由-自由梁弹性机体模型,给出了自由-自由梁弯曲振动的一个近似解,并与实测值进行了对比,结果表明这个近似解具有较大的适用性.介绍了飞机机体刚体模态和一阶弯曲振动模态的飞机机体二质量块等效模型,研究了最大起飞质量及最小飞行质量2种情形下着陆时的机体弹性特征,探讨了弹性飞机起落架设计与刚性飞机相比在技术上的重大变化,为起落架设计中考虑飞机弹性影响提供了简化模型、直观概念和可靠依据.     

冠心病治疗进展

冠心病是严重危害人类健康的全球性疾病,也是患者病死的主要原因之一．本文就其药物治疗、介入治疗、外科手术治疗及基因治疗做一综述,以便为临床治疗冠心病提供参考．     

预应力混凝土T型刚构桥挂篮悬浇施工的挠度控制

随着科学技术及工程施工技术的不断进步和发展,挂篮悬臂施工已经成为现代大跨度桥梁建造的主要施工方法。结合某桥的一些实际施工情况,探讨大跨度预应力混凝土连续刚构箱梁在使用挂篮悬臂浇筑施工时,如何控制好每个施工阶段的挠度,设置好各个梁段在施工中的预拱度,使得桥梁最终达到理想线形。