ADO意义.NET在并发控制方面存在的问题及解决方案

针对ADO.NET在处理"丢失的修改"问题时,不支持"关键字和已修改字段"的并发控制问题提出了相应的解决办法;同时对ADO.NET架构本身带来的异常更新问题提供了解决思路.     

基于循环经济模式的交通运输可持续发展研究

文章阐明了循环经济的基本概念和基本理论，在分析我国交通运输业可持续发展面临的诸多问题后，结合循环经济模式对我国交通运输可持续发展战略进行了研究。     

建筑与寻常景观——华南理工大学建筑设计院创作室环境设计

从设计定位、空间布局、技术细节三方面入手,详细介绍了华南理工大学建筑设计院创作室环境设计的理念和手法。论述了作为建筑设计事务所周边环境的设计,如何做到如寻常景观一般与原有环境相融合的协调,并从中总结经验和教训。     

Structural Changes of Water Molecules Upon the Reduction of Quinones in The Reaction Center from Rhodobactery Sphaeroides

1 Results The photosynthetic bacterial reaction center (RC) is a membrane protein complex.The RC is composed of three protein subunits and redox components such as bacteriochlorophylls, bacteriopheophytins,and quinones.The RC performs the photochemical electron transfer from the bacteriochlorophyll dimer through a series of electron donor and acceptor molecules to a secondary quinone,QB.QB accepts electrons from a primary quinone,QA,in two sequential electron transfer reactions.The second electron trans...     

浅谈随刊附盘的著录与管理

介绍了随刊附盘的种类及其验收与著录的方法,提出了随刊附盘管理和利用的措施。     

用酉几何构作笛卡尔认证码

利用有限域上的酉几何构作了一个笛卡尔认证码，并计算了它们的参数。此外，假定根据均匀概率分布选择编码规则，计算了模仿攻击与替换攻击成功的概率的最大值Ｐ１与Ｐｓ。     

Transgenesis in fish

Gene transfer into fish embryo is being performed in several species (trout, salmon, carps, tilapia, medaka, goldfish, zebrafish, loach, catfish, etc.). In most cases, pronuclei are not visible and microinjection must be done into the cytoplasm of early embryos. Several million copies of the gene are generally injected. In medaka, transgenesis was attempted by injection of the foreign gene into the nucleus of oocyte. Several reports indicate that the injected DNA was rapidly replicated in the early phase of embryo development, regardless of the origin and the sequence of the foreign DNA. The survival of the injected embryos was reasonably good and a large number reached maturity. The proportion of transgenic animals ranged from 1 to 50% or more, according to species and to experimentators. The reasons for this discrepancy have not been elucidated. In all species, the transgenic animals were mosaic. The copy number of the foreign DNA was different in the various tissues of an animal and a proportion lower than 50% of F1 offsprings received the gene from their parents. This suggests that the foreign DNA was integrated into the fish genome at the two cells stage or later. An examination of the integrated DNA in different cell types of an animal revealed that integration occurred mainly during early development. The transgene was found essentially unrearranged in the fish genome of the founders and offsprings. The transgenes were therefore stably transmitted to progeny in a Mendelian fashion. Southern blot analysis revealed the presence of possible junction fragments and also of minor bands which may result from a rearrangement of the injected DNA. In all species, the integrated DNA appeared mainly as random end-to-end concatemers. In adult trout blood cells, a small proportion of the foreign DNA was maintained in the form of non-integrated concatemers, as judged by the existence of end fragments. The transgenes were generally only poorly expressed. The majority of the injected gene constructs contained essentially mammalian or higher vertebrates sequences. The comparison of the expression efficiency of these constructs in transfected fish and mammalian cells indicates that some of the mammalian DNA sequences are most efficiently understood by the fish cell machinery. Chloramphenicol acetyl transferase gene under the control of promoters from Rous sarcoma virus, and human cytomegalovirus, was expressed in several tissues of transgenic fish. Chicken delta-crystallin gene was expressed in several tissues of transgenic fish.(ABSTRACT TRUNCATED AT 400 WORDS)     

T＝∞跟踪问题的一种解法

跟踪问题是线性系统二次型性能指标最优控制讨论的一个重要应用问题。当终端时间T为有限时 ,很多文献都给出了适当的解法 ,但T =∞时的求解还有很多问题值得探讨。本文给出了终端T =∞时预期输出满足一定条件的跟踪问题的一种解法。此种情况可转化为输出调节器问题 ,并给出了具体的求解方法和例子。