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891.
Acylsilanes react with lithium α-silyl ester enolates to provide β-silyl-α,β-unsaturated esters having predominantly the (Z) geometry. These esters were reacted with Grignard reagents and with lithium aluminum hydride to give the corresponding (Z) 3-silyl allyl alcohols. 相似文献
892.
Mette Ø. Filsø Dr. Michael J. Turner Prof. Gerald V. Gibbs Prof. Stefan Adams Prof. Mark A. Spackman Prof. Bo B. Iversen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15535-15544
The understanding of lithium‐ion migration through the bulk crystal structure is crucial in the search for novel battery materials with improved properties for lithium‐ion conduction. In this paper, procrystal calculations are introduced as a fast, intuitive way of mapping possible migration pathways, and the method is applied to a broad range of lithium‐containing materials, including the well‐known battery cathode materials LiCoO2, LiMn2O4, and LiFePO4. The outcome is compared with both experimental and theoretical studies, as well as the bond valence site energy approach, and the results show that the method is not only a strong, qualitative visualization tool, but also provides a quantitative measure of electron‐density thresholds for migration, which are correlated with theoretically obtained activation energies. In the future, the method may be used to guide experimental and theoretical research towards materials with potentially high ionic conductivity, reducing the time spent investigating nonpromising materials with advanced theoretical methods. 相似文献
893.
Gerald Rafler Gerhard Reinisch Eckhard Bonatz Heinz Versaumer Herbert Gajewski Hans-Dieter Sparing 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1413-1427
For a four-parameter reaction-mass transport model of melt polycondensation, the constants of polycondensation, thermolysis, and diffusion were determined by means of experiments in thin-layer polycondensation. Based on these constants, the convectional mass transport and efficient melt thickness in polycondensation systems under conditions of compelled mixing can be estimated. However, for stirred polycondensation systems a reaction-mass transfer model proves more suitable. The constants of polycondensation and thermolysis obtained by the diffusion model can be transferred to the reaction-mass transfer model. Thus, only the mass transfer coefficient has to be determined. 相似文献
894.
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895.
Henri-Jean Cristau Gerald Duc Lydie Labaudiniere Francoine Pietrasanta Francoise Plenat 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):113-116
Abstract The synthesis of 1, 2 vinylene bisphosphonium salts 1 has now been enlarged to the vinylogous 1, 4-butadienylene bisphosphonium salts 2. The salts 2, a new class of unsaturated disalts, have also been prepared through a two-step isomerisation of acetylenic salts. New aspects of the reactivity of salts 1 and the comparative study of salts 2 (selective cleavage reactions of P-C bonds and reactions with nucleophiles having a mobile hydrogen) are described. This reactivity allows the preparation of new series of phosphonium salts substituted by heteroatomic groups. 相似文献
896.
Sina Schwendemann Shunsuke Oishi Prof. Dr. Susumu Saito Dr. Roland Fröhlich Dr. Gerald Kehr Prof. Dr. Gerhard Erker 《化学:亚洲杂志》2013,8(1):212-217
D ‐(+)‐Camphor forms the enamine 2 with piperidine. Compound 2 adds HB(C6F5)2 at the enamine carbon atom C3 to form a Lewis acid/Lewis base adduct (exo‐/endo‐isomers of 3 ). Exposure of 3 to dihydrogen (2.5 bar, room temperature) leads to heterolytic splitting of H2 to form the H+/H? addition products ( 4 , two diastereoisomers) of the “invisible” frustrated Lewis pairs ( 5 , two diastereoisomers) that were apparently generated in situ by enamine hydroboration under equilibrium conditions. 相似文献
897.
Sebastian Dochow Claudia Beleites Thomas Henkel Günter Mayer Jens Albert Joachim Clement Christoph Krafft Jürgen Popp 《Analytical and bioanalytical chemistry》2013,405(8):2743-2746
Three important technical innovations are reported here towards Raman-activated cell sorting. Firstly, a microfluidic chip made of quartz is introduced which integrates injection of single cells, trapping by laser fibres and sorting of cells. Secondly, a chip holder was designed to provide simple, accurate and stable adjustment of chips, microfluidic connections and the trapping laser fibres. The new setup enables to the collection of Raman spectra of single cells at 785 nm excitation with 10 s exposure time. Lastly, a new type of modelling the various background contributions is described, improving Raman-based cell identification by the classification algorithm linear discriminant analysis. Mean sensitivity and specificity determined by iterated 10-fold cross validation were 96 and 99 %, respectively, for the distinction of leucocytes extracted from blood, breast cancer cells BT-20 and MCF-7, and leukaemia cells OCI-AML3. 相似文献
898.
Gerald Ziegenbalg 《Nachrichten aus der Chemie》2015,63(9):879-883
899.
Biller JR Meyer V Elajaili H Rosen GM Kao JP Eaton SS Eaton GR 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,212(2):370-377
Optimization of nitroxides as probes for EPR imaging requires detailed understanding of spectral properties. Spin lattice relaxation times, spin packet line widths, nuclear hyperfine splitting, and overall lineshapes were characterized for six low molecular weight nitroxides in dilute deoxygenated aqueous solution at X-band. The nitroxides included 6-member, unsaturated 5-member, or saturated 5-member rings, most of which were isotopically labeled. The spectra are near the fast tumbling limit with T1∼T2 in the range of 0.50–1.1 μs at ambient temperature. Both spin–lattice relaxation T1 and spin–spin relaxation T2 are longer for 15N- than for 14N-nitroxides. The dominant contributions to T1 are modulation of nitrogen hyperfine anisotropy and spin rotation. Dependence of T1 on nitrogen nuclear spin state mI was observed for both 14N and 15N. Unresolved hydrogen/deuterium hyperfine couplings dominate overall line widths. Lineshapes were simulated by including all nuclear hyperfine couplings and spin packet line widths that agreed with values obtained by electron spin echo. Line widths and relaxation times are predicted to be about the same at 250 MHz as at X-band. 相似文献
900.
Improving the sensitivity of a humidity sensor based on fiber bend coated with a hygroscopic coating
Jinesh Mathew Yuliya Semenova Ginu Rajan Pengfei Wang Gerald Farrell 《Optics & Laser Technology》2011,43(7):1301-1305
A highly sensitive all-fiber humidity sensor is demonstrated. The sensor behaves as a humidity dependent optical switch between 85% and 90% RH. This sensor also offers the advantages of simple structure and low cost and its response is fast and reversible in nature. The typical humidity response of the sensor is suitable for using it as a human breath rate monitor. 相似文献