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排序方式: 共有542条查询结果,搜索用时 375 毫秒
51.
Photochemical sensing of NO(2) with SnO(2) nanoribbon nanosensors at room temperature 总被引:7,自引:0,他引:7
52.
Akikawa H Ajimura S Chrien RE Eugenio PM Franklin GB Franz J Gang L Imai K Khaustov P May M Pile PH Quinn B Rusek A Sasao J Sawafta RI Schmitt H Tamura H Tang L Tanida K Yuan L Zhou SH Zhu LH Zhu XF 《Physical review letters》2002,88(8):082501
With a germanium detector array (Hyperball), we observed two gamma-ray peaks corresponding to the two transitions (5/2(+)-->1/2(+) and 3/2(+)-->1/2(+)) in the (9)(Lambda)Be hypernucleus which was produced by the 9Be(K-,pi(-)) reaction. The energies of the gamma rays are 3029 +/- 2 +/- 1 keV and 3060 +/- 2 +/- 1 keV. The energy difference was measured to be 31.4(+2.5)(-3.6) keV, which indicates a very small Lambda-spin-dependent spin-orbit force between a Lambda and a nucleon. This is the smallest level splitting by far ever measured in a hypernucleus. 相似文献
53.
W. Franklin Smyth 《Fresenius' Journal of Analytical Chemistry》1979,297(4):260-261
Summary A course on Analytical Chemistry for the life sciences currently conducted at the Chemistry Department of Chelsea College, London, is described. This course has three main components: Lectures on the analysis of materials of biological importance, practical experiments using both chemical and instrumental methods, and lectures from experts of other departments on specialized fields of application.
Analytische Chemie für die Biowissenschaften
Zusammenfassung Ein Ausbildungsplan für Analytische Chemie wird beschrieben wie er gegenwärtig in der chemischen Abteilung des Chelsea College, London, für Biowissenschaftler in Anwendung ist. Die Ausbildung umfaßt folgende drei Teile: Vorlesungen über die Analyse von biologisch relevanten Materialien, Praktika in chemischen und instrumentellen Analysenmethoden und Vorlesungen von einschlägigen Experten über spezielle Anwendungsgebiete.相似文献
54.
Jerrold Franklin 《Nuclear Physics B》1978,138(1):122-140
Electron-proton deep inelastic scattering is treated as the incoherent scattering of electrons by bound Dirac partons in the proton rest frame. An approximate bound state wave function is used for the initial parton, while the final parton is considered free. A good fit is obtained to the structure function F1(x,Q2) in the range x > 0.15, Q2 > 2 GeV. The subsequent prediction for F2(x,Q2) is not as good, indicating a small additional contribution by longitudinal photons for W < 2.5 GeV. The parton momentum distribution is found to contain transverse momentum of 400–600 MeV, increasing with x. 相似文献
55.
Parity-violating electron deuteron scattering and the proton's neutral weak axial vector form factor
Ito TM Averett T Barkhuff D Batigne G Beck DH Beise EJ Blake A Breuer H Carr R Clasie B Covrig S Danagoulian A Dodson G Dow K Dutta D Farkhondeh M Filippone BW Franklin W Furget C Gao H Gao J Gustafsson K Hannelius L Hasty R Hawthorne-Allen AM Herda MC Jones CE King P Korsch W Kowalski S Kox S Kramer K Lee P Liu J Martin JW McKeown RD Mueller B Pitt ML Plaster B Quéméner G Réal JS Ritter J Roche J Savu V Schiavilla R Seely J Spayde D Suleiman R Taylor S Tieulent R Tipton B Tsentalovich E 《Physical review letters》2004,92(10):102003
We report on a new measurement of the parity-violating asymmetry in quasielastic electron scattering from the deuteron at backward angles at Q2=0.038 (GeV/c)2. This quantity provides a determination of the neutral weak axial vector form factor of the nucleon, which can potentially receive large electroweak corrections. The measured asymmetry A=-3.51+/-0.57 (stat)+/-0.58 (syst) ppm is consistent with theoretical predictions. We also report on updated results of the previous experiment at Q2=0.091 (GeV/c)2, which are also consistent with theoretical predictions. 相似文献
56.
A numerical study of the guided modes in a water-saturated poroelastic plate that obeys the Biot theory is presented. In the first part, we study the leaky guided modes and the angular resonances when the slow wave does not propagate. Two types of guided modes exist. The first ones occur from coupling of the fast longitudinal wave with the shear wave; most of them propagate whatever the frequency is, provided that it is not close to their cut-off frequencies. The leaky guided modes of the second type occur from coupling of the two longitudinal waves and the shear wave. These modes do not propagate (they are highly damped) as long as the slow wave remains diffusive. We show that the characteristics of the angular resonances can be linked to the leaky guided waves of the first type in the same way as for an elastic plate. The guided modes of the second type may not be associated to angular resonances. In the second part, we consider a thinner plate in a higher frequency range so that the slow wave can propagate. Once again its influence is studied both on the leaky guided modes and on the angular resonances. 相似文献
57.
A concise, six-step, enantioselective synthesis of (-)-epimyrtine employing the N-sulfinyl delta-amino beta-ketoester chiral building block is described. 相似文献
58.
Yuan-Qing Qiao Franklin D. Tall 《Proceedings of the American Mathematical Society》2003,131(12):3929-3936
In this paper we prove the equivalence between the existence of perfectly normal, non-metrizable, non-archimedean spaces and the existence of ``generalized Souslin lines", i.e., linearly ordered spaces in which every collection of disjoint open intervals is -discrete, but which do not have a -discrete dense set. The key ingredient is the observation that every first countable linearly ordered space has a dense non-archimedean subspace.
59.
Dynamic nuclear polarization studies of nitroxyl spin probes in agarose gel using Overhauser‐enhanced magnetic resonance imaging 下载免费PDF全文
V. Meenakumari Hideo Utsumi Fuminori Hyodo A. Jawahar A. Milton Franklin Benial 《Magnetic resonance in chemistry : MRC》2017,55(11):1022-1028
Agarose is a tissue‐equivalent material and its imaging characteristics similar to those of real tissues. Hence, the dynamic nuclear polarization studies of 3‐carboxy‐2,2,5,5‐tetramethyl‐pyrrolidine‐1‐oxyl (carboxy‐PROXYL) in agarose gel were carried out. The dynamic nuclear polarization parameters such as spin lattice relaxation time, longitudinal relaxivity, leakage factor, saturation parameter and coupling parameter were estimated for 2 mM carboxy‐PROXYL in phosphate‐buffered saline solution and water/agarose mixture (99 : 1). From these results, the spin probe concentration was optimized as 2 mM, and the reduction in enhancement was observed for carboxy‐PROXYL in water/agarose mixture (99 : 1) compared with phosphate‐buffered saline solution. Phantom imaging was also performed with 2 mM concentration of carboxy‐PROXYL in various concentrations of agarose gel at various radio frequency power levels. The results from the dynamic nuclear polarization measurements agree well with the phantom imaging results. These results pave the way for designing model system for human tissues suited to the biological applications of electron spin resonance/Overhauser‐enhanced magnetic resonance imaging. 相似文献
60.