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281.
Adam NE Alexander JP Berkelman K Cassel DG Duboscq JE Ecklund KM Ehrlich R Fields L Galik RS Gibbons L Gittelman B Gray R Gray SW Hartill DL Heltsley BK Hertz D Hsu L Jones CD Kandaswamy J Kreinick DL Kuznetsov VE Mahlke-Krüger H Meyer TO Onyisi PU Patterson JR Peterson D Pivarski J Riley D Rosner JL Ryd A Sadoff AJ Schwarthoff H Shepherd MR Sun WM Thayer JG Urner D Wilksen T Weinberger M Athar SB Avery P Breva-Newell L Patel R Potlia V Stoeck H Yelton J Rubin P Cawlfield C Eisenstein BI 《Physical review letters》2005,94(1):012005
Using CLEO data collected from CESR e(+)e(-) collisions at the psi(2S) resonance and nearby continuum at sqrt[s]=3.67 GeV, we report the first significantly nonzero measurements of light vector-pseudoscalar hadron pair production (including rhopi, omegapi, rhoeta, and K(*0)K0 ) and the pi(+)pi(-)pi(0) final state, both from psi(2S) decays and direct e(+)e(-) annihilation. 相似文献
282.
C. Grivas T.C. May-Smith D.P. Shepherd R.W. Eason 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1203-1206
Pulsed laser deposition of epitaxial, single-crystal Nd:Gd3Ga5O12 (Nd:GGG) films on Y3Al5O12 substrates with thicknesses up to 135 m and propagation losses as low as 0.1 dB/cm is reported. Rutherford backscattering spectrometry has shown constant stoichiometry for the films throughout their depth. Fluorescence properties were similar to that of the bulk Nd:GGG crystal used as a target material for the deposition and lasing action has been observed at 1059.0 and 1060.6 nm after pumping by a Ti:sapphire laser operating at 808 nm. A laser threshold of 18 mW has been obtained and a slope efficiency of 17.5% has been observed using an output coupler of 4.5%. The low losses in combination with the high numerical aperture (0.75) and the thickness of the structures make them suitable for high-power diode pumping. PACS 42.70.Hj; 42.55.-f; 42.82.Et; 42.79.Gn; 81.15.Fg 相似文献
283.
Boyd DR Sharma ND Ljubez V Byrne BE Shepherd SD Allen CC Kulakov LA Larkin MJ Dalton H 《Chemical communications (Cambridge, England)》2002,(17):1914-1915
Dioxygenase-catalysed trioxygenation of alkyl phenyl sulfides and alkyl benzenes yields enantiopure cis-dihydrodiol sulfoxides and triols respectively; naphthalene cis-dihydrodiol dehydrogenase-catalysed aromatisation of these diastereoisomers gives enantiopure catechols of either configuration. 相似文献
284.
The Bingham fluid model was developed to represent viscoplastic materials that change from rigid bodies at low stress to viscous fluids at high stress – a process termed yielding. Such a fluid model is used in the modeling of slurries, which occur frequently in food processing and other engineering applications. 相似文献
285.
Rhona F. Lonergan Georgina A. Conway Dr. Patrick W. Doheny Dr. Helena J. Shepherd 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(64):e202201823
Accelerated ageing reactions that take place between two solid materials on contact in the absence of added solvent have been used to synthesize two spin-crossover-active 1D coordination polymers and one of their Cu(II) analogues. The hygroscopy of the ligands and the relative humidity of the reaction chamber have been shown to be particularly important factors in the rate of reaction. Small-scale reactions between a few individual crystals have allowed observation of deliquescence of the 4-aminotriazole ligand at high humidity. The metal salt does not dissolve, and the ligand diffuses into the crystal of the metal salt during the reaction. In the case of the Cu analogue, the formation of the product causes the crystal of the metal salt to deform with the formation of pseudocrystals, which have a fibrous structure. 相似文献
286.
Oscar A. Douglas-Gallardo Ian Shepherd Simon J. Bennie Kara E. Ranaghan Adrian J. Mulholland Esteban Vöhringer-Martinez 《Journal of computational chemistry》2020,41(24):2151-2157
Ribulose 1,5-bisphosphate carboxylase-oxygenase (RuBisCO) is the main enzyme involved in atmospheric carbon dioxide (CO2) fixation in the biosphere. This enzyme catalyzes a set of five chemical steps that take place in the same active-site within magnesium (II) coordination sphere. Here, a set of electronic structure benchmark calculations have been carried out on a reaction path proposed by Gready et al. by means of the projector-based embedding approach. Activation and reaction energies for all main steps catalyzed by RuBisCO have been calculated at the MP2, SCS-MP2, CCSD, and CCSD(T)/aug-cc-pVDZ and cc-pVDZ levels of theory. The treatment of the magnesium cation with post-HF methods is explored to determine the nature of its involvement in the mechanism. With the high-level ab initio values as a reference, we tested the performance of a set of density functional theory (DFT) exchange-correlation (xc) functionals in reproducing the reaction energetics of RuBisCO carboxylase activity on a set of model fragments. Different DFT xc-functionals show large variation in activation and reaction energies. Activation and reaction energies computed at the B3LYP level are close to the reference SCS-MP2 results for carboxylation, hydration and protonation reactions. However, for the carbon–carbon bond dissociation reaction, B3LYP and other functionals give results that differ significantly from the ab initio reference values. The results show the applicability of the projector-based embedding approach to metalloenzymes. This technique removes the uncertainty associated with the selection of different DFT xc-functionals and so can overcome some of inherent limitations of DFT calculations, complementing, and potentially adding to modeling of enzyme reaction mechanisms with DFT methods. 相似文献
287.
Zeynep Gültekin Elghareeb E. Elboray Moustafa F. Aly Hussien H. Abbas-Temirek Helena J. Shepherd Ronald Grigg 《Tetrahedron》2014
We report the spatially controlled, protecting group free, catalytic assembly of a library of nineteen 7-component cascade products generated from a novel planar trisallenyl 1,3,5-triazinane-2,4,6-trione core in combination with aryl iodides and amines with excellent regio and good stereoaselectivity for Z,Z,Z-isomers. 相似文献
288.
M. Shepherd E. R. Weaver P. G. Ledig Aktiebolaget Carba K. Melanby H. L. Harden P. Borinski H. Murschhauser R. Staufer R. Krais H. Markert H. Mogilnickij H. Heinicke K. Heimberger L. C. Mc Nair H. C. Gull St. Hediger E. Lieber R. Rosen K. M. Watson N. H. Ceaglske 《Analytical and bioanalytical chemistry》1933,94(1-2):34-42
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