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排序方式: 共有175条查询结果,搜索用时 250 毫秒
171.
L. J. Bunce Kazuyuki Saitô J. D. Maitland Wright 《Proceedings of the American Mathematical Society》1999,127(10):2975-2979
Schaefer and Zhang have recently obtained an analogue, for sequentially order continuous functionals on , of a much earlier theorem of Dixmier. In this note it is shown that the Schaefer-Zhang Theorem has a natural generalisation to non-commutative -algebras. These results are obtained as consequences of our main theorem which is concerned with affine functions on compact convex sets.
172.
Richard A. Bunce James E. Schammerhorn LeGrande M. Slaughter 《Journal of heterocyclic chemistry》2007,44(5):1051-1057
A series of 2‐methyl‐2‐(2‐nitrobenzyl)‐substituted β‐keto ester derivatives has been subjected to reductive cyclization under hydrogenation conditions to assess the importance of the ester group position on the diastereoselectivity of the process. Hydrogenation over 5% palladium‐on‐carbon at 4 atmospheres pressure resulted in formation of (±)‐2,3‐dialkyl‐1,2,3,4‐tetrahydroquinoline‐3‐carboxylic esters with a preference for the product isomer having the C2 alkyl cis to the C3 ester. The product ratios were synthetically useful (6‐16:1), but less than that observed in cyclizations to prepare (±)‐2‐alkyl‐1,2,3,4‐tetrahydroquinoline‐4‐carboxylic esters. The reduced selectivity in the current reactions has been rationalized in terms of the greater conformational mobility around the ester bearing carbon, which decreases the ability of the ester to sterically influence the addition of hydrogen to the final imine intermediate. 相似文献
173.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Akimoto R Alexander J Al-Ta'ani H Andrews KR Angerami A Aoki K Apadula N Appelt E Aramaki Y Armendariz R Aschenauer EC Awes TC Azmoun B Babintsev V Bai M Bannier B Barish KN Bassalleck B Basye AT Bathe S Baublis V Baumann C Bazilevsky A Belmont R Ben-Benjamin J Bennett R Berdnikov A Berdnikov Y Blau DS Bok JS Boyle K Brooks ML Broxmeyer D Buesching H Bumazhnov V Bunce G Butsyk S Campbell S Caringi A Castera P Chen CH Chi CY Chiu M Choi IJ 《Physical review letters》2011,106(6):062001
Large parity-violating longitudinal single-spin asymmetries A(L)(e+) = -0.86(-0.14) (+0.30) and A(L)(e-) = 0.88(-0.71) (+0.12) are observed for inclusive high transverse momentum electrons and positrons in polarized p+p collisions at a center-of-mass energy of sqrt[s] = 500 GeV with the PHENIX detector at RHIC. These e± come mainly from the decay of W± and Z0 bosons, and their asymmetries directly demonstrate parity violation in the couplings of the W± to the light quarks. The observed electron and positron yields were used to estimate W± boson production cross sections for the e± channels of σ(pp → W+ X) × BR(W+ → e+ ν(e)) = 144.1 ± 21.2(stat)(-10.3) (+3.4) (syst) ± 21.6(norm) pb, and σ(pp → W- X) × BR(W- → e- ν[over ˉ](e)) = 31.7 ± 12.1(stat)(-8.2) (+10.1) (syst) ± 4.8(norm) pb. 相似文献
174.
The title compound was prepared in 29.5% overall yield using a five-step sequence involving two tandem reactions. The current work supports the earlier finding that a strong thermodynamic preference exists for an all-cis relationship across the three contiguous stereocenters at C(1), C(3a), and C(7a). 相似文献
175.
Adare A Afanasiev S Aidala C Ajitanand NN Akiba Y Al-Bataineh H Alexander J Aoki K Aphecetche L Armendariz R Aronson SH Asai J Atomssa ET Averbeck R Awes TC Azmoun B Babintsev V Baksay G Baksay L Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bazilevsky A Belikov S Bennett R Berdnikov Y Bickley AA Boissevain JG Borel H Boyle K Brooks ML Buesching H Bumazhnov V Bunce G Butsyk S Campbell S Chang BS Charvet JL Chernichenko S Chiba J Chi CY Chiu M Choi IJ Chujo T Chung P 《Physical review letters》2008,101(12):122301
Yields for J/psi production in Cu+Cu collisions at sqrt s_NN=200 GeV have been measured over the rapidity range |y|<2.2 and compared with results in p+p and Au+Au collisions at the same energy. The Cu+Cu data offer greatly improved precision over existing Au+Au data for J/psi production in collisions with small to intermediate numbers of participants, in the range where the quark-gluon plasma transition threshold is predicted to lie. Cold nuclear matter estimates based on ad hoc fits to d+Au data describe the Cu+Cu data up to N_part approximately 50, corresponding to a Bjorken energy density of at least 1.5 GeV/fm(3). 相似文献