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101.
Akhat V. Il'Yasov Ildus A. Nuretdinov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):479-482
Spectra of a nuclear magnetic resonance of seleno- and telluro-phosphorus compounds on nuclei 77Se, 125Te, 31P are described. The dependences of spectral parameters on a structure of the substitutes at phosphorus atom in these compounds are discussed. 相似文献
102.
语义地图构建对移动机器人导航与规划具有重要意义,而环境分类是语义地图构建的核心问题。目前所采用的环境分类方法匹配率较低,已成为语义地图构建所面临的主要问题。对此笔者提出了一种基于支持向量机的分类方法,该方法利用激光雷达数据提取环境几何特征,训练SVM分类器对机器人工作空间模式进行识别,并将所提算法用于室内环境的语义分类。实验结果表明,该分类方法具有较高的识别率,可有效地实现语义地图构建。 相似文献
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Luca Fusaro Giulia Mameli Francesca Mocci Michel Luhmer Giovanni Cerioni 《Magnetic resonance in chemistry : MRC》2012,50(2):152-158
17O NMR is not routinely used for structure characterization, and kinetic studies of fluxional organic compounds are seldom undertaken because poor sensitivity and fast quadrupole relaxation are frequently regarded as intractable issues. This work shows how, nowadays, quantitative 17O dynamic NMR studies on small organic molecules are feasible without enrichment being needed. It reports on acetoxysilanes, a class of fluxional compounds whose structure and dynamics were to be clarified. Natural abundance 17O NMR spectra were recorded over a wide range of temperatures using standard instrumentation. The analysis relies on simple linewidth measurements and directly provides the activation parameters. The activation enthalpy is found to decrease with increasing number of acetoxy groups bound to silicon. Density functional theory calculations properly predict this trend and show that a single oxygen atom of the acetoxy group is bound to silicon, excluding chelation as binding mode, and that the dynamic process involves the shift of the silicon atom between the two oxygen atoms of the acetoxy group. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Trifluoromethylation‐Initiated Remote Cross‐Coupling of Carbonyl Compounds to Form Carbon–Heteroatom/Carbon Bonds 下载免费PDF全文
Lin Huang Dr. Sheng‐Cai Zheng Prof. Dr. Bin Tan Prof. Dr. Xin‐Yuan Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6718-6722
By involving the reversal of conventional reactivity expectations without external oxidants, we describe a novel and convenient protocol of remote cross‐coupling of carbonyl compounds with a series of common and simple nucleophiles. This cross‐coupling is triggered by radical trifluoromethylation of alkenes, thereby achieving highly selective remote difunctionalization of alkenes and α‐position of the carbonyl group for facile access to trifluoromethyl α‐halo‐ and α‐cyanocarbonyl compounds. The reaction exhibits a broad substrate scope with excellent functionality tolerance and many different types of nucleophiles; further synthetic applicability of the obtained compounds proved to be suitable, thus showing great potential for synthetic utility. 相似文献
108.
《Physics and Chemistry of Liquids》2012,50(3):149-166
Abstract The structure factor for liquid lead at the temperatures 613 K, 643 K, 863 K and 1163 K are measured by neutron diffraction. Extensive comparisons to earlier measurements are made as well as comparisons to different hard-core models. 相似文献
109.
Stereoselective route to tricyclo[5.3.1.01,5]undecane and bicyclo[4.2.0]octane ring systems present in the molecular structure of tricycloillicinone, cedrenoids and endiandric acid, elysiapyrones, respectively, is described. A tandem oxidative dearomatization of o-hydroxymethylphenol, π4s+π2s cycloaddition, reactivity modulation in excited state and ring-closing metathesis are the key features of our approach. 相似文献
110.
S. S. Nath D. Chakdar G. Gope A. Talukdar D. K. Avasthi 《Journal of Dispersion Science and Technology》2013,34(7):1111-1113
We report synthesis of ZnS quantum dots by chemical method at room temperature. In this technique, ZnS quantum dots are produced by simple chemical reactions where zeolite, acts as matrix, plays the key role in controlling particle growth during synthesis. Quantum dots exhibit luminescence properties such as Zn2+ related emission, efficient low voltage electroluminescence, and super linear voltage-brightness EL characteristics. This study demonstrates the technological importance of semiconductor nanosystems prepared by low cost chemical route. 相似文献