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991.
We present experimental Lagrangian statistics of finite sized, neutrally bouyant, particles transported in an isotropic turbulent flow. The particle's diameter is varied over turbulent inertial scales. Finite size effects are shown not to be trivially related to velocity intermittency. The global shape of the particle's acceleration probability density functions is not found to depend significantly on its size while the particle's acceleration variance decreases as it becomes larger in quantitative agreement with the classical k(-7/3) scaling for the spectrum of Eulerian pressure fluctuations in the carrier flow. 相似文献
992.
993.
Christophe Werlé Chih-Juo Madeline Yin Frank W. Heinemann Christina Hauser Karsten Meyer 《Tetrahedron letters》2017,58(28):2715-2719
The efficient multi-step, large-scale synthesis, spectroscopic characterization and solid-state molecular structure of a new type of three-fold functionalized, sterically demanding triazine is reported. The aromatic heterocycle 6,6′,6′'-((1,3,5-triazine-2,4,6-triyl)tris(methylene))tris(2,4-di-tert-butylphenol) possesses three 2,4-di-tert-butylphenol synthons bound to the 1,3,5-triazine ring via synthetically challenging methylene linkages in the 2,4,6 positions. The key to success was found in the generation of a highly reactive imidate hydrochloride salt, namely ethyl 2-(3,5-di-tert-butyl-2-methoxyphenyl)acetimidate hydrochloride, that readily undergoes cyclotrimerization. The reported preparation opens new perspectives in the design and synthesis of novel triazine molecules bearing flexible and sterically demanding functionalized groups for various applications. 相似文献
994.
Cheick Thiam Christophe Bobin Jacques Bouchard 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(2):591-597
Designed for triple to double coincidence ratio measurements based on liquid scintillation, the three-photomultipliers detection system can also be applied for Cherenkov counting using aqueous solutions. For activity determination, a specific modelling of Cherenkov light emission has to be constructed. For that purpose, the analytical modelling first developed at PTB was adapted to account for the physical features of the detection system used at LNHB. The first results are presented in the case of activity measurements of two high-energy β?-emitters (90Y and 89Sr). The analytical modelling was also tested for the standardization of 68Ge in a solution of 68Ge/68Ga in equilibrium in the framework of a BIPM international comparison in 2014. 相似文献
995.
Dr. Uttam Chakraborty Dr. Serhiy Demeshko Prof. Dr. Franc Meyer M. Sc. Christophe Rebreyend Prof. Dr. Bas de Bruin Prof. Dr. Mihail Atanasov Prof. Dr. Frank Neese Dr. Bernd Mühldorf Prof. Dr. Robert Wolf 《Angewandte Chemie (International ed. in English)》2017,56(27):7995-7999
The 15 valence-electron iron(I) complex [CpArFe(IiPr2Me2)] ( 1 , CpAr=C5(C6H4-4-Et)5; IiPr2Me2=1,3-diisopropyl-4,5-dimethylimidazolin-2-ylidene) was synthesized in high yield from the FeII precursor [CpArFe(μ-Br)]2. 57Fe Mössbauer and EPR spectroscopic data, magnetic measurements, and ab initio ligand-field calculations indicate an S= 3/2 ground state with a large negative zero-field splitting. As a consequence, 1 features magnetic anisotropy with an effective spin-reversal barrier of Ueff=64 cm−1. Moreover, 1 catalyzes the dehydrogenation of N,N-dimethylamine–borane, affording tetramethyl-1,3-diaza-2,4-diboretane under mild conditions. 相似文献
996.
Kinetics of Lifetime Changes in Bimetallic Nanocatalysts Revealed by Quick X‐ray Absorption Spectroscopy 下载免费PDF全文
Dr. Matthias Filez Dr. Hilde Poelman Dr. Evgeniy A. Redekop Dr. Vladimir V. Galvita Dr. Konstantinos Alexopoulos Dr. Maria Meledina Dr. Ranjith K. Ramachandran Dr. Jolien Dendooven Prof. Christophe Detavernier Prof. Gustaaf Van Tendeloo Dr. Olga V. Safonova Dr. Maarten Nachtegaal Prof. Bert M. Weckhuysen Prof. Guy B. Marin 《Angewandte Chemie (International ed. in English)》2018,57(38):12430-12434
997.
998.
Dr. Camille Lecourt Sabrina Dhambri Khalil Yamani Dr. Guillaume Boissonnat Dr. Simon Specklin Dr. Etienne Fleury Karim Hammad Eric Auclair Serge Sablé Dr. Antonio Grondin Dr. Paola B. Arimondo Dr. François Sautel Dr. Georges Massiot Dr. Christophe Meyer Prof. Dr. Janine Cossy Dr. Geoffroy Sorin Dr. Marie-Isabelle Lannou Prof. Dr. Janick Ardisson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(11):2745-2749
A strategy for the assembly of the entire carbon backbone of a stereoisomer of the antitumor marine natural product hemicalide has been investigated. The devised convergent approach relies on Horner–Wadsworth–Emmons and Julia–Kocienski olefination reactions for the construction of the C6=C7 and C34=C35 double bonds, respectively, an aldol reaction to create the C27−C28 bond, and a Suzuki–Miyaura cross-coupling as the endgame to form the C15−C16 bond. 相似文献
999.
Rahima Sidi-Boulenouar Maïda Cardoso Christophe Coillot Sébastien Rousset Eric Nativel Alain Charbit Christelle Baptiste Eric Alibert Frédéric Gatineau Jean-Luc Verdeil Christophe Goze-Bac 《Magnetic resonance in chemistry : MRC》2019,57(9):749-756
Today, in the presence of global warming, understanding how plants respond to drought stress is essential to meet the challenge of developing new cultivars and new irrigation strategies, consistent with the maintenance of crop productivity. In this context, the study of the relation between plants and water is of central interest for modeling their responses to biotic and abiotic constraints. Paradoxically, there are very few direct and noninvasive methods to quantify and measure the level and the flow of water in plants. The present work aims to develop a noninvasive methodology for living plant based on nuclear magnetic resonance (NMR) at low magnetic field and imaging (MRI) to tackle the issue of water quantity in plants. For this purpose, a portable NMR device measuring the signal level at 8 mT was built. This instrument addresses specific challenges such as miniaturization, accessibility, and overheating in order to maintain the plant intact of time over long period. Time dependence of the water content in sorghum plants is reported under abiotic stress as well as the fraction of transpirable soil water and the photosynthesis activity through the leaves. At high magnetic field (9.4 T), T2 maps were acquired on the same sorghum plants at two time points. The combination of these approaches allows us to identify ecophysiological biomarkers of drought stress. One particular interesting result concerns the spatial distribution of water in two anatomically contrasted sorghum genotypes. 相似文献
1000.
Ataulla Shegiwal Alan M. Wemyss Mike A. J. Schellekens Jens de Bont James Town Evelina Liarou Georgios Patias Christophe J. Atkins David M. Haddleton 《Journal of polymer science. Part A, Polymer chemistry》2019,57(3):E1-E9
We present a systematic study of incorporating carboxyl groups into latex particles to enhance colloidal stability and the physical properties of the latex. Statistical copolymers of methacrylic acid and methyl methacrylate) were synthesized via catalytic chain transfer polymerization (CCTP) in emulsion. The vinyl‐terminated oligomers were in turn successfully utilized as chain transfer agents for the formation of diblock and pseudo triblock copolymers via sulfur‐free reversible addition–fragmentation chain transfer polymerization (SF‐RAFT). These copolymers were characterized using 1H NMR, size exclusion chromatography (SEC), dynamic light scattering (DLS), dynamic mechanical analysis (DMA), contact angle measurements and matrix‐assisted laser desorption/ionization time of flight mass spectroscopy (MALDI‐TOF‐MS) techniques. © 2019 The Authors. Journal of Polymer Science Part A: Polymer Chemistry published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, E1–E9 相似文献