Synthesis of Chiral Sulfoxides and Application in Enantioselective Allylation of Aldehydes with Allyltrichlorosilane

1 Results The enantioselective addition of allylic organometallic reagents to aldehydes is a fundamental tool in organic synthesis.The high degree of both diastereo-and enantioselectivity gives the possibility to obtain a wide series of homoallylic alcohols,versatile intermediates in a great number of synthesis[1]. One of the most successful approaches is related to the discovery that organocatalytic activation of the nucleophilic allyltrichlorosilanes by means of neutral Lewis bases,such as formamides,...     

利益基础与战略选择——中日"战略互惠关系"之发展态势浅析

从国际关系理论视角出发,对2006年末安倍晋三访华以来中日关系出现的新变化进行了分析和解读.在理解中日"战略互惠关系"要义的基础上,主要根据国家战略反映国际身份认同、国际身份认同影响国家利益认识、国家利益认识又作用于国际关系的逻辑,从国家战略和国家利益两方面来分析中日"战略互惠关系"的前景.     

图的k-顶点着色与k-边着色的Groebner基求解

利用Groebner基方法给出了任意有限图的尼一顶点着色与k-边着色的求解方案,从而求得图的后．顶点着色方案和顶点色数,k-边着色方案和边色数．     

吉尔伯特·牛顿·路易斯：未获诺贝尔奖的化学大师

 吉尔伯特·牛顿·路易斯是20世纪最伟大的化学家之一。他因在发展热力学理论并将其应用于实际化学系统方面做出了重大贡献，被认为是现代化学热力学奠基人；因其提出的共价键和电子对概念促成现代化学键理论的产生，被认为是共价键发现者；他提出的酸碱概念是对化学科学的另一个重要的贡献。路易斯曾41次获得诺贝尔化学奖提名，但从未获奖，这也成为诺贝尔奖历史上的巨大争议之一。介绍了路易斯的人生经历和科学成就，盘点了其科学探索的历程。     

构建昆明体育训练基地科研服务体系的思考

科研设施及服务能力是大型综合性训练基地的重要组成部分。文章将重点介绍国外主要体育训练基地的科研设施及服务能力,对构建昆明体育训练基地的科研设施及服务能力提出建议,以期对昆明体育训练基地的建设提供参考。     

DENOISING AND HARMONIC DETECTION USING NONORTHOGONAL WAVELET PACKETS IN INDUSTRIAL APPLICATIONS

New industrial applications call for new methods and new ideas in signal analysis. Wavelet packets are new tools in industrial applications and they have just recently appeared in projects and patents. In training neural networks, for the sake of dimensionality and of ratio of time, compact information is needed. This paper deals with simultaneous noise suppression and signal compression of quasi-harmonic signals. A quasi-harmonic signal is a signal with one dominant harmonic and some more sub harmonics in superposition. Such signals often occur in rail vehicle systems, in which noisy signals are present. Typically, they are signals which come from rail overhead power lines and are generated by intermodulation phenomena and radio interferences. An important task is to monitor and recognize them. This paper proposes an algorithm to differentiate discrete signals from their noisy observations using a library of nonorthonormal bases. The algorithm combines the shrinkage technique and techniques in regression analysis using Shannon Entropy function and Cross Entropy function to select the best discernable bases. Cosine and sine wavelet bases in wavelet packets are used. The algorithm is totally general and can be used in many industrial applications. The effectiveness of the proposed method consists of using as few as possible samples of the measured signal and in the meantime highlighting the difference between the noise and the desired signal. The problem is a difficult one, but well posed. In fact, compression reduces the level of the measured noise and undesired signals but introduces the well known compression noise. The goal is to extract a coherent signal from the measured signal which will be “well represented” by suitable waveforms and a noisy signal or incoherent signal which cannot be “compressed well” by the waveforms. Recursive residual iterations with cosine and sine bases allow the extraction of elements of the required signal and the noise. The algorithm that has been developed is utilized as a filter to extract features for training neural networks. It is currently integrated in the inferential modelling platform of the unit for Advanced Control and Simulation Solutions within ABB’s industry division. An application using real measured data from an electrical railway line is presented to illustrate and analyze the effectiveness of the proposed method. Another industrial application in fault detection, in which coherent and incoherent signals are univocally visible, is also shown.     

构建异议股东股份收买请求权制度研究

股东利益的保护是公司治理的核心问题,而对小股东利益的保护更是保护股东利益的关键所在.借公司法修改之契机,介绍了一种重要且行之有效的保护中小股东利益的制度：异议股东股份收买请求权制度,并且对该制度在我国的构建作出了全面深入的分析,提出了自己的立法建议.     

基于三阶染色体结构的自适应进化规划及应用

针对模糊辨识中规则数多少难以选择、输入量在各规则中重要程度难以确定以及模糊规则参数难以优化等问题,模拟生物基因之间相互联系的特点,用三阶染色体结构对完全模糊规则基进行描述。根据每代不同个体的适应度信息获得不同个体的变异率,采用自适应进化规划算法,实现模糊规则基各级染色体引导优化,克服了用试凑方法确定参数对辨识精度的消极影响,算法的复杂程度大大减小,为模糊建模提供了一种新颖的方案。通过对两类不同非线性系统的仿真,证明了此方法的有效性。     

铁路地道桥微机CAD系统的研究与设计

用于铁路地道桥辅助设计的微机CAD系统,可以对力学计算结果进行数据检索与处理,建立图形库,辅助配筋和自动绘制钢筋混凝土框架配筋图.同时介绍了该软件系统的设计构思,主要程序的设计方法和制图质量控制等技术问题.     

二级微商法确定弱酸碱电位滴定终点准确度的分析

从理论上分析了二级微商法确定电位滴定终点对强酸碱、弱酸碱准确度的影响。发现在一定的条件下 ,只有 Ka≤ 1.13× 10 -7时 ,用二级微商法确定电位滴定终点才能提高准确度 ,而对于 Ka或 Kb比较大 ,以至于强酸碱 ,二级微商法确定电位滴定终点并不能提高准确度。另外 ,在终点附近 ,滴定体积应小而相等 ,也有利于提高分析结果的准确度。