排序方式: 共有35条查询结果,搜索用时 187 毫秒
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Bourgeois P Sato Y Shaw J Alarcon R Bernstein AM Bertozzi W Botto T Calarco J Casagrande F Distler MO Dow K Farkondeh M Georgakopoulos S Gilad S Hicks R Holtrop M Hotta A Jiang X Karabarbounis A Kirkpatrick J Kowalski S Milner R Miskimen R Nakagawa I Papanicolas CN Sarty AJ Sirca S Six E Sparveris NF Stave S Stiliaris E Tamae T Tsentalovich G Tschalaer C Turchinetz W Zhou ZL Zwart T 《Physical review letters》2006,97(21):212001
The mean square polarizability radii of the proton have been measured for the first time in a virtual-Compton-scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities obtained from a dispersion analysis of the data at Q2 = 0.057 GeV2/c2 are in agreement with O(p3) heavy baryon chiral perturbation theory. The data support the dominance of mesonic effects in the polarizabilities. 相似文献
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Andivahis L Bosted PE Lung A Stuart LM Alster J Arnold RG Chang CC Dietrich FS Dodge W Gearhart R Gomez J Griffioen KA Hicks RS Hyde-Wright CE Keppel C Kuhn SE Lichtenstadt J Miskimen RA Peterson GA Petratos GG Rock SE Rokni S Sakumoto WK Spengos M Swartz K Szalata Z Tao LH 《Physical review D: Particles and fields》1994,50(9):5491-5517
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LUDVÍK BENEŠ KLÁRA MELÁNOVÁ JAN SVOBODA VÍTĚZSLAV ZIMA 《Journal of inclusion phenomena and macrocyclic chemistry》2006,55(3-4):289-293
Intercalates of o-, m-, and p-toluidine into α-Zr(HPO4)2 · H2O were prepared and characterized by powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. As follows from IR, toludine molecules are protonated in the interlayer space. Toluidine molecules are arranged in a bimolecular way in the intercalates containing more than 1.5 toluidine molecules per Zr atom. On the other hand, a monolayer of the toluidine molecules is supposed in the intercalates with less than one toluidine molecule per Zr atom. 相似文献
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Biomolecular homochirality, the origin of which is still a puzzle, has challenged scientists to design chemical systems that provide chiral molecules through absolute asymmetric synthesis and to amplify a small stereochemical bias in such systems. The photoresolution of the enantiomers of helical-shaped, sterically overcrowded alkene 1 with circularly polarized light and the transduction of the stereochemical information by triggering the helical arrangement of a large collection of achiral molecules in a twisted nematic liquid crystalline phase (2) are examples of control and amplification of chirality. 相似文献
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Numerous organic and inorganic laboratory standards were gathered from nine European and North American laboratories and were analyzed for their delta(18)O values with a new on-line high temperature pyrolysis system that was calibrated using Vienna standard mean ocean water (VSMOW) and standard light Antartic precipitation (SLAP) internationally distributed reference water samples. Especially for organic materials, discrepancies between reported and measured values were high, ranging up to 2 per thousand. The reasons for these discrepancies are discussed and the need for an exact and reliable calibration of existing reference materials, as well as for the establishment of additional organic and inorganic reference materials is stressed. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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Larin I McNulty D Clinton E Ambrozewicz P Lawrence D Nakagawa I Prok Y Teymurazyan A Ahmidouch A Asratyan A Baker K Benton L Bernstein AM Burkert V Cole P Collins P Dale D Danagoulian S Davidenko G Demirchyan R Deur A Dolgolenko A Dzyubenko G Ent R Evdokimov A Feng J Gabrielyan M Gan L Gasparian A Gevorkyan S Glamazdin A Goryachev V Gyurjyan V Hardy K He J Ito M Jiang L Kashy D Khandaker M Kingsberry P Kolarkar A Konchatnyi M Korchin A Korsch W Kowalski S Kubantsev M Kubarovsky V Li X Martel P 《Physical review letters》2011,106(16):162303
High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst) eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions. 相似文献
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A review is presented of the calculation of photoionization spectra, particularly in the spectral range where electron autoionization of diatomic molecules takes place. In addition to some interesting results obtained over years that compare favourably with experiment, the emphasis here is put on the relation between the methods developed for the calculation of observables associated with the continuum energy spectrum of the electrons and the Alchemy system of programs. This system of programs serves as a basis for initial and intermediate calculations. The examples presented show that diatomic molecules not only in gas phase but also oriented in space or physisorbed at surfaces may be studied readily. 相似文献
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