Propagation of projective synchronization in a series connection of chaotic systems

Projective synchronization is a type of chaos synchronization where the response system states are scaled replicas of the drive system states. This paper deals with the propagation of projective synchronization in a series connection of N chaotic discrete-time drive systems and N response systems. By exploiting an observer-based approach, the paper demonstrates that dead-beat projective synchronization (i.e., exact synchronization in finite time for any scaling factor) is achieved between the nth drive and nth response systems. In particular, it is shown that projective synchronization starts from the innermost (Nth) drive-response system pair and propagates toward the outermost (first) drive-response system pair. Only a single scalar synchronizing signal connects the cascaded drive and response systems. Finally, an example illustrates the propagation of different types of chaos synchronization in a series connection consisting of a Gingerbreadman map, a third order hyperchaotic Henon map and a Lozi map.     

The 2006 Benjamin Franklin Medal in Chemistry presented to Samuel J. Danishefsky, Ph.D.

Organic synthesis of natural products began in 1828 with Wohler's synthesis of urea, the first time a substance derived from a living organism had been produced by combining inorganic materials. Progress in the field was slow at first, due to the limited purification and analytical methods. Advances in those areas gave rise to rapid progress in synthesis, as chemists could now focus their energies on devising new approaches to the preparation of increasingly complex molecules. While it is possible to prepare many molecules by using known chemistry in new combinations, real progress has been the result of keen insight and creativity on the part of only a few individuals.Professor Samuel J. Danishefsky established himself early on as a leader in this field when he recognized that a well-known ring forming reaction could be greatly extended by adding chemical functionality to one of the components. He then found that these new reactive components could react with heretofore unreactive components to produce new rings containing oxygen atoms both in the ring and as attachments to the ring. These products were very similar to naturally occurring sugars. Danishefsky realized that he could develop this chemistry further to produce precisely defined polysaccharides as well. Some of these polysaccharides occur on the surface of cancer cells. Using the chemistry he developed, he was able to prepare these cancer cell markers, and after combining them with certain proteins, showed that the resulting molecules behaved as cancer vaccines. Several have entered clinical trial.Danishefsky has synthesized many other natural products, but he is particularly interested in those that may be useful in treating cancer. His syntheses allow for the modification of the final product in ways that improve both safety and efficacy. Several of these compounds have also entered clinical trials. Thus his work has not only advanced the art and science of organic synthesis, but stands to make dramatic advances in the treatment of cancer as well.     

初始缺陷和拉-弯耦合对于叠层板的振动屈曲和非线性动力稳定性的影响

研究了复合材料叠层板的初始缺陷和拉伸-弯曲耦合对于其振动、屈曲和非线性动力稳定性的影响,推导了控制方程,这是一个修正的非线性Mathieu方程,进行了5种典型复合材料的数值计算,它们是玻璃环氧Scotch-1002,芳纶环氧Kevlar-49,硼环氧B4/5505,石墨环氧T300/5208和AS/3501,结果表明,由于初始缺陷以及耦合效应的存在,使叠层板对于进入参数共振更加敏感,并且其振幅大于无初始缺陷或者无耦合效应的叠层板,对于不同材料的复合叠层板,尤其是层数较少的板,耦合效应是不相同的,在板结构的屈曲和动力稳定性设计中,如果忽略了耦合效应的影响,其不安全性将超过10％以上。     

Child studies, religion, and science: the life and work of head teacher Jens Olsen

Jens Olsen (1840–1911), head principal of the Danish town of Varde was in many ways typical for his time. He was an engaging teacher and school reformer. But he was also a Christian, a believer in the ideas of the Danish priest, N. F. S. Grundtvig. Last but not least, he was curious. His curiosity and interest in the nature of children brought him in contact with the Anglo-American movement of child study. This chapter tells the story of how child studies became his way of trying to bridge the gap between the Darwinian approach to the history of humanity and a Christian view.     

体育优质课评课的若干思考--对重庆市首届中小学体育教师基本功大赛的感想

当前的体育优质课中存在的主要问题有：体育优质课成了“表演课”；评优课场地器材等设施不切合实际；参赛教师的业务水平有待提高。建议评优课不采用集中比赛的方式，而采用随时抽查方法，这样才能真正反映体育教师的业务水平。     

排球运动员战术意识的培养

战术意识是排球运动员必须具备且需要不断提高的一种重要能力，它是运动员在比赛中技战术水平得到有效发挥的前提条件。从训练、比赛等多个方面阐述了排球运动员战术意识的培养途径和方法。     

篮球专修学生临场执裁能力的培养

针对目前篮球专修学生中存在的临场执裁能力较差的现状,分析了问题产生的原因,并提出了改革理论教学方法、注重理论结合实践、充分采用信息反馈手段等若干措施.     

从医学角度看竞技体育的价值

与竞技体育一样，医学的工作对象也是人，最终目标也是为提高人的体质服务，所以竞技体育与医学之间存在着密切的联系。从医学角度来“透视”竞技体育，为人们更全面地理解竞技体育的价值提供参考。     

体育教育专业体育游戏课的创新教育

论述了创新教育及其与素质教育、大学体育教学的关系，指出了培养学生的创造能力是大学体育教育改革的核心，阐明了在体育教育专业体育游戏深中培养学生创新意识的内容与方法。