爆破作用时间对工程爆破质量的影响

本文介绍了爆破作用时间。对工程爆破质量影响的研究结果。研究表明,增加爆破作用时间对改善爆破破碎质量起了重要作用。实验室研究、工业试验和生产实践证明,改变药包结构和形状,爆破技术和充填等方法可延长爆破作用时间,以提高工程爆破破碎质量。     

Quantitative Estimates of Outcrossing Rates in a Natural Population of Caldesia grandis （Alismataceae）

Outcrossing rate in a natural population of Caldesia grandis was estimated by the dominant random amplified polymorphism DNA (RAPD) marker using 10 open-pollinated progeny arrays of 24 individuals. The multilocus outcrossing rate estimated based on all 25 RAPD loci was 0.872 ±0.033 and the single-locus outcrossing rate was 0.795 ±0.032. Multilocus estimates did not differ significantly from the single-locus estimates. The fixation index, F, in the progeny estimated from RAPD data was -0.142 ±0.000. The estimates of multilocus outcrossing rates (t_m) and single-locus outcrossing rates (t_s) obtained from MLDT clearly indicate that outcrossing is predominant in the open-pollinated C. grandis population. An empirical analysis suggests that 15 should be the minimum number of dominant marker loci necessary to achieve robust estimates of t_m.     

叶绿体DNA种内多样化

着重讨论了９科３２种植物叶绿体ＤＮＡ种内多样化，进而探讨叶绿体ＤＮＡ种内多样化的遗传学基础和意义。     

地高辛标记DNA探针应用于凝胶转移电泳

半抗原DIG-ddUTP与DNA连接,以此作为探针可以与其相识别的蛋白质相结合,再用带有碱性磷酸的抗体处理,形成的复合物可作用于底物CSPD,使其产生萤光,而被x光片记录下来。     

分布式关系型数据库管理系统C-POREL的代码生成机制设计

分布式数据库管理系统(DDBMS)中,代码生成模块是实现系统的分布透明性(分割透明性和分配透明性)的重要模块,其设计得好坏对整个系统有极大的影响。本文以分布式关系型数据库管理系统C-POREL的代码生成机制为例,讨论DDBMS中的代码生成层的设计方法。文中给出C-POREL系统的代码生成模块的设计方案,并提出了其中所必须的一些算法,最后给出了具体的例子。     

物之分割与重聚对物权的影响——以物之运动为观察视角

分割与重聚是一种物运动变化的普遍现象,但对物权的影响并不总是积极的.经济学分析为我们克服这种消极影响提供了法学思考的路径:物在分割与重聚过程中,其法律关系具有特殊性,对此法律在制度设计层面上有不同的回应,以此为基础构建了不同的分割与重聚制度.分割之物在重聚过程中可能并不足以产生量的标准意义上的所有权,但他们之间实际存在的牵连关系从质的分割重聚标准看来则有可能已经是一种新的财产关系.     

Mitochondrial DNA variation in social wasps (Hymenoptera,Vespidae)

Summary Patterns of restriction fragment length polymorphisms (RFLP) of European Vespinae were more similar within genera than between them. Distance trees were constructed that support the hypothesis of monophyly of the generaVespula andDolichovespula. Within the genusVespula, V. germanica was more closely related toV. rufa than toV. vulgaris. The position of the genusVespa remained uncertain due to the precision limits of the RFLP technique.     

烟草薄层培养早期细胞核形态与核DNA含量变化的研究

通过应用ＤＮＡ专一性活体荧光染色剂Ｈｏｅｃｈｅｓｔ３３２５８对烟草茎表皮细胞薄层培养物的细胞核进行活体染色，发现在培养早期，细胞核发生了明显变化，由分化时的一般扁圆形和靠壁的位置逐渐变成圆形和居中的位置；核体积增大；染色质结构由致密变得疏松；而后染色质凝缩，发生无丝分裂；经数次分裂之后，细胞形态较一致，通过单细胞核内ＤＮＡ含量的测定，发现细胞分裂之前，核ＤＮＡ含量不增加；而最初几次分裂之后，含量减     

Covalent binding of aflatoxin B1 to liver DNA in rats pretreated with ethanol

Summary Male Fischer F-344 rats were given ethanol in the drinking water and/or by single oral administration. Following this, the animals received p.o. 100 ng/kg of the hepatocarcinogen [³H]aflatoxin B₁ (AFB₁). 24 h later, the level of DNA-bound AFB₁ was determined in the liver and was found not to be affected by any type of ethanol pretreatment. A cocarcinogenic effect of ethanol in the liver is therefore unlikely to be due to an effect on the metabolic activation and inactivation processes governing the formation of DNA-binding AFB₁ metabolites.To whom correspondence should be addressed.Acknowledgment. We thank the European Science Foundation for the Toxicology Research Fellowship awarded to M.M.     

最大匹配问题Tile自组装模型

Tile自组装模型凭借其自组装、可编程等特性在解决NP问题方面具有巨大优势.文中提出了一种求解最大匹配问题的Tile自组装新模型,该模型主要由初始配置子系统、选择子系统及检测子系统3大部分构成.新模型中首先设计Tile分子存储问题信息,其次通过Tile分子自组装操作生成最大匹配问题解空间,最后通过Tile检测分子筛选得到最大匹配问题的解.对模型从所需Tile分子种类、计算时间和计算空间3个方面进行性能分析,并通过实验模拟论证了模型的有效性和正确性.