排序方式: 共有126条查询结果,搜索用时 46 毫秒
71.
Using a small scale test-rig a number of experiments were performed in which the imposed disk velocity v
disk, the different mechanical parameters of the test-rig (damping c and tangential stiffness k), and normal load were varied independently. 相似文献
72.
Dr. Yovan de Coene Dr. Olivier Deschaume Dr. Yuqing Zhang Arne Billen Jing He Stephanie Seré Dr. Stefan Knoppe Prof. Dr. Stijn Van Cleuvenbergen Prof. Dr. Thierry Verbiest Prof. Dr. Koen Clays Prof. Dr. Jian Ye Prof. Dr. Carmen Bartic 《Chemphyschem》2019,20(13):1765-1774
Gold nanoparticles (AuNPs) are regarded as promising building blocks in functional nanomaterials for sensing, drug delivery and catalysis. One remarkable property of these particles is the localized surface plasmon resonance (LSPR), which gives rise to augmented optical properties through local field enhancement. LSPR also influences the nonlinear optical properties of metal NPs (MNPs) making them potentially interesting candidates for fast, high resolution nonlinear optical imaging. In this work we characterize and discuss the wavelength dependence of the hyper-Rayleigh scattering (HRS) behavior of spherical gold nanoparticles (GNP) and gold nanorods (GNR) in solution, from 850 nm up to 1300 nm, covering the near-infrared (NIR) window relevant for deep tissue imaging. The high-resolution spectral data allows discriminating between HRS and two photon photoluminescence contributions. Upon particle aggregation, we measured very large enhancements (ca. 104) of the HRS intensity in the NIR, which is explained by considering aggregation-induced plasmon coupling effects and local field enhancement. These results indicate that purposely designed coupled nanostructures could prove advantageous for nonlinear optical imaging and biosensing applications. 相似文献
73.
Bram Verbelen Stijn Boodts Johan Hofkens Noël Boens Wim Dehaen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(15):4695-4699
We describe herein the first radical C H arylation of BODIPY dyes. This novel, general, one‐step synthetic procedure uses ferrocene to generate aryl radical species from aryldiazonium salts and allows the straightforward synthesis of brightly fluorescent (Φ>0.85) 3,5‐diarylated and 3‐monoarylated boron dipyrrins in up to 86 % yield for a broad range of aryl substituents. In this way, new and complex dyes with red‐shifted spectra can be easily prepared. 相似文献
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Kaval N Singh BK Ermolat'ev DS Claerhout S Parmar VS der Eycken JV der Eycken EV 《Journal of combinatorial chemistry》2007,9(3):446-453
A new transition metal-catalyzed orthogonal solid-phase protocol for the synthesis of highly substituted 2(1H)-pyrazinones was developed, on the basis of Chan-Lam arylation and Liebeskind-Srogl cross-coupling reactions. This strategy opens the way for the generation of small libraries of 2(1H)-pyrazinone analogues for biological screening. 相似文献
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Dr. Eduard Badarau Dr. K. Harsha Vardhan Reddy Dr. Aurore Loudet Dr. Charles Simon Dr. Laurent Trembleau Dr. Stijn Claerhout Dr. Etienne Pair Stéphane Massip Dr. Philippe Breton Dr. Brigitte Lesur Dr. Solo Goldstein Dr. Jean-Marie Fourquez Dr. Jean Michel Henlin Prof. Léon Ghosez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15477-15481
Identification of a common Diels–Alder pattern in three classes of bioactive natural products led us to study the synthesis and cycloaddition of a new class of cyclic dienes readily available from β,γ-unsaturated lactams. A practical and readily scalable route to the parent p-methoxybenzyl-protected 6- and 7-membered β,γ-unsaturated lactams was developed. These were readily transformed into the corresponding O-silylated dienes, which were reacted with dimethyl and diethyl fumarate to yield stereoselectively highly functionalized bicyclic adducts. These exhibited unexpected and versatile transformations upon acid hydrolysis depending on the nature of the dienophile substituents and the acid catalyst. All reactions have been performed on multigram quantities. These transformations provide a convenient, economical, and easily scalable pathway for the rapid construction of functionally and stereochemically dense privileged scaffolds for the construction of libraries of natural products-inspired molecules of pharmacological relevance. 相似文献
77.
Sendroiu IE Mertens SF Schiffrin DJ 《Physical chemistry chemical physics : PCCP》2006,8(12):1430-1436
The effects of interparticle distance on the UV-visible absorption spectrum of gold nanocrystals aggregates in aqueous solution have been investigated. The aggregates were produced by ion-templated chelation of omega-mercaptocarboxylic acid ligands covalently attached to the nanoparticles surface. Variation of the ligand chain length provides control over the interparticle separation in the aggregates. The UV-visible spectra consist typically of a single particle band and a secondary band at higher wavelengths associated with the formation of aggregates in solution. The position of the latter depends on interparticle separation up to distances of approximately 8 nm, in accordance with existing models. Potential applications therefore include distance sensitive labels or proximity probes. Conversely, variation of the ligand length allows the preparation of nanostuctured materials with tuned optical properties. 相似文献
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Bram Verbelen Lucas Cunha Dias Rezende Stijn Boodts Jeroen Jacobs Prof. Luc Van Meervelt Prof. Johan Hofkens Prof. Wim Dehaen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(36):12667-12675
A one‐step synthetic procedure for the radical C?H alkylation of BODIPY dyes has been developed. This new reaction generates alkyl radicals through the oxidation of boronic acids or potassium trifluoroborates and allows the synthesis of mono‐, di‐, tri‐, and tetraalkylated fluorophores in a good to excellent yield for a broad range of organoboron compounds. Using this protocol, multiple bulky alkyl groups can be introduced onto the BODIPY core thus creating solid‐state emissive BODIPY dyes. 相似文献
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