Adaptive subwavelength control of nano-optical fields

Adaptive shaping of the phase and amplitude of femtosecond laser pulses has been developed into an efficient tool for the directed manipulation of interference phenomena, thus providing coherent control over various quantum-mechanical systems. Temporal resolution in the femtosecond or even attosecond range has been demonstrated, but spatial resolution is limited by diffraction to approximately half the wavelength of the light field (that is, several hundred nanometres). Theory has indicated that the spatial limitation to coherent control can be overcome with the illumination of nanostructures: the spatial near-field distribution was shown to depend on the linear chirp of an irradiating laser pulse. An extension of this idea to adaptive control, combining multiparameter pulse shaping with a learning algorithm, demonstrated the generation of user-specified optical near-field distributions in an optimal and flexible fashion. Shaping of the polarization of the laser pulse provides a particularly efficient and versatile nano-optical manipulation method. Here we demonstrate the feasibility of this concept experimentally, by tailoring the optical near field in the vicinity of silver nanostructures through adaptive polarization shaping of femtosecond laser pulses and then probing the lateral field distribution by two-photon photoemission electron microscopy. In this combination of adaptive control and nano-optics, we achieve subwavelength dynamic localization of electromagnetic intensity on the nanometre scale and thus overcome the spatial restrictions of conventional optics. This experimental realization of theoretical suggestions opens a number of perspectives in coherent control, nano-optics, nonlinear spectroscopy, and other research fields in which optical investigations are carried out with spatial or temporal resolution.     

仿射非线性一般模型控制的鲁棒稳定性分析

针对基于仿射非线性系统的一般模型控制(GMC)方法进行了鲁棒稳定性分析。首先证明了如果模型存在一个严格Lyapunov函数,当模型与过程的失配在一定范围内时,则过程总是Lyapunov稳定的。由此推广到采用GMC方法的闭环控制系统,在给出其显式控制律的前提下,证明了满足一定前提条件下,采用GMC的闭环控制系统总是Lya-punov稳定的。     

Large Cretaceous sphenodontian from Patagonia provides insight into lepidosaur evolution in Gondwana

Sphenodontian reptiles successfully radiated during Triassic and Jurassic times, but were driven almost to extinction during the Cretaceous period. The sparse Early Cretaceous record of sphenodontians has been interpreted as reflecting the decline of the group in favour of lizards, their suspected ecological successors. However, recent discoveries in Late Cretaceous beds in Patagonia partially modify this interpretation. Numerous skeletons of a new sphenodontian, Priosphenodon avelasi gen. et sp. nov., were collected from a single locality in the Cenomanian-Turonian Candeleros Formation, where it is more abundant than any other tetrapod group recorded in the quarry (for example, Crocodyliformes, Serpentes, Dinosauria and Mammalia). Adult specimens of Priosphenodon reached one metre in length, larger than any previously known terrestrial sphenodontian. Here we propose, using available evidence, that sphenodontians were not a minor component of the Cretaceous terrestrial ecosystems of South America, and that their ecological replacement by squamates was delayed until the early Tertiary. The new discovery helps to bridge the considerable gap in the fossil record (around 120 million years) that separates the Early Cretaceous sphenodontians from their living relatives (Sphenodon).     

基于Simplex-annealing混合方法的模型参数估计

针对现有算法的导数依赖性及其局部优化性能 ,为控制工程中的模型参数估计课题提供一种新思路。把具有概率突跳特性模拟退火 (SA)和基于高维 Euclid空间中凸多面体结构的单纯形搜索法 (SM)有机地结合 ,通过对搜索操作和参数的有效设计 ,提出了一种基于 Sim plex- annealing混合算法 (SMSA)的模型参数估计方法。对以传递函数、状态空间和自回归滑动平均 (ARMA)模型形式表达的不同典型对象进行仿真 ,结果表明 :SMSA方法在模型结构已知的情况下可准确地估计参数 ,其性能明显优于单一遗传算法(GA)     

Development of Postgraduate Education in Chemical Engineering

1 Development of Postgraduate Education There were only 200 postgraduates were honored master degree from the year 1935 to 1949 in old China. While, after the establishment of new China, the postgraduate education has developed in a certain degree, there were 23,000 postgraduates were enrolled from 1950 to 1965, and there were no postgraduates during the period of 1966 to 1977 due to the "culture revolution".     

一类非线性系统的快速鲁棒故障诊断

.结合在线估计器和滑模观测器方法,基于所给出的一种新的自适应学习算法,提出了一种针对非线性不确定系统的鲁棒故障诊断方法.滑模观测器可以消除建模不确定性的影响以得到准确的状态估计,而在线估计器可以实时估计故障的大小.在此,基于李亚普诺夫函数,在理论上证明了所给出的状态和参数估计误差都是一致有界的;针对三容水箱DTS200所做的仿真实验,其结果验证了该方法的可行性.研究结果表明,由于滑模项的引入,使得该方法的故障检测时间大大缩短,其性能比Polycarpou所提出的在线估计器方法的性能要好.     

CHARACTERIZATION OF SOL-GEL-DERIVED ZrO2 FILM BY PHOTOTHERMAL RADIOMETRY

In modern industry,thin film on the substratc has much important role to decide the properties of product, especially for electrical, optical and wear-resistant etc, production. There are some technical methods to prepare thin film,including plasma spray,physical vapor deposition (PVD),chemical vapor deposition (CVD) and sol-gel,etc. Among of them,sol-gel method has been developed a popular tech nique for preparing thin films.     

Regulation of primary cilia formation and left-right patterning in zebrafish by a noncanonical Wnt signaling mediator, duboraya

Primary cilia are microtubule-based organelles that project from the surface of nearly every animal cell. Although important functions of primary cilia in morphogenesis and tissue homeostasis have been identified, the mechanisms that control the formation of primary cilia are not understood. Here we characterize a zebrafish gene, termed duboraya (dub), that is essential for ciliogenesis. Knockdown of dub in zebrafish embryos results in both defects in primary cilia formation in Kupffer's vesicle and randomization of left-right organ asymmetries. We show that, at the molecular level, the function of dub in ciliogenesis is regulated by phosphorylation, which in turn depends on Frizzled-2-mediated noncanonical Wnt signaling. We also provide evidence that, at the cellular level, dub function is essential for actin organization in the cells lining Kupffer's vesicle. Taken together, our findings identify a molecular factor that links noncanonical Wnt signaling with the control of left-right axis specification, and provide an entry point for analyzing the mechanisms that regulate primary cilia formation.