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91.
A convenient procedure for the iodination of many substituted phenols uses chloramine T and sodium iodide in DMF, DMSO, or acetonitrile. 相似文献
92.
Mr. J. M. Watt 《Numerische Mathematik》1968,12(1):11-22
Discretizations of nonlinear operators in Banach space are described and the concept of an inverse discretization introduced. In the main part of the paper, the very general formalism of BUTCHER for the initial value problem for ordinary differential equations is examined and the sufficiency of conditions for its stability and convergence is demonstrated. The order of convergence of these methods is discussed, and an example is given. 相似文献
93.
94.
An experimental system using integral interferometric imaging and computer tomography for visualizing the structure of a turbulent, vertical helium jet is described. Integral images and tomographic integral data were obtained using a pulsed phase-shifted interferometer. The integral images revealed a sinuous overall jet structure and large-scale buckling motions in the far-field. Tomographic reconstruction of jet cross-sections at numerous axial locations were made for three turbulent jets at two different Reynols numbers, 2,800 and 4,300. Tomographic images revealed unmixed ambient fluid far inside the jet boundary and a bimodal concentration distribution. Image interpretation and experimental errors are discussed. 相似文献
95.
96.
Parsons W.M. Ballard E.O. Bartsch R.R. Benage J.F. Bennett G.A. Bowers R.L. Bowman D.W. Brownell J.H. Cochrane J.C. Davis H.A. Ekdahl C.A. Gribble R.F. Griego J.R. Goldstone P.D. Jones M.E. Hinckley W.B. Hosack K.W. Kasik R.J. Lee H. Lopez E.A. Lindemuth I.R. Monroe M.D. Moses R.W. Jr. Ney S.A. Platts D. Reass W.A. Salazar H.R. Sandoval G.M. Scudder D.W. Shlachter J.S. Thompson M.C. Trainor R.J. Valdez G.A. Watt R.G. Wurden G.A. Younger S.M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(2):205-211
Atlas is a facility being designed at Los Alamos National Laboratory (LANL) to perform high-energy-density experiments in support of weapon physics and basic research programs. It is designed to be an international user facility, providing experimental opportunities to researchers from national laboratories and academic institutions. For hydrodynamic experiments, it will be capable of achieving a pressure exceeding 30 Mbar in a several cubic centimeter volume. With the development of a suitable opening switch, it will be capable of producing more than 3 MJ of soft X-rays. The capacitor bank design consists of a 36 MJ array of 240 kV Marx modules. The system is designed to deliver a peak current of 45-50 MA with a 4-5-μs rise time. The Marx modules are designed to be reconfigured to a 480-kV configuration for opening switch development. The capacitor bank is resistively damped to limit fault currents and capacitor voltage reversal. An experimental program for testing and certifying prototype components is currently under way. The capacitor bank design contains 300 closing switches. These switches are a modified version of a railgap switch originally designed for the DNA-ACE machines. Because of the large number of switches in the system, individual switch prefire rates must be less than 10-4 to protect the expensive target assemblies. Experiments are under way to determine if the switch-prefire probability can be reduced with rapid capacitor charging 相似文献
97.
In this paper the relation betweenEP--matrices andE
k
P--matrices over an arbitrary filedF is studied. Further, conditions for the product ofE
k
P--matrices to be anE
k
P--matrix and for the reverse order law to hold for the polynomial Moore-Penrose inverse of the product ofE
k
P--matrices are determined 相似文献
98.
S. F. J. Cox G. H. Eaton D. S. Sivia M. S. Watt D. W. Cooke M. Leon M. A. Paciotti J. L. Smith W. L. Hults T. L. Estle B. Hitti C. Boekema J. Lam A. Morrobel-Sosa R. L. Lichti J. Oostens C. Schwab E. A. Davis A. Singh N. Ayres De Campos J. Ayres De Campos P. J. Mendes J. M. Gil K. Chow R. Duvarney P. F. Meier 《Hyperfine Interactions》1994,85(1):59-65
Cross relaxation between implanted positive muons and27Al nuclei in Al metal, lightly doped with Cu to impede the muon diffusion, shows weak resonances at 2.3 and 4.0 mT. Assignment of these to polarization transfervia the 1/2 3/2 and 3/2 5/2 transitions of the (J=5/2) spins leads to a quadrupole coupling constante
2qQ/h=1.8(1) MHz,i.e. an electric field gradient on Al nuclei immediately adjacent to the muon siteq=0.048(3) a.u., with a small departure from axial symmetry. 相似文献
99.
Identification of novel small-molecule inhibitors of severe acute respiratory syndrome-associated coronavirus by chemical genetics 总被引:5,自引:0,他引:5
Kao RY Tsui WH Lee TS Tanner JA Watt RM Huang JD Hu L Chen G Chen Z Zhang L He T Chan KH Tse H To AP Ng LW Wong BC Tsoi HW Yang D Ho DD Yuen KY 《Chemistry & biology》2004,11(9):1293-1299
The severe acute respiratory syndrome-associated coronavirus (SARS-CoV) infected more than 8,000 people across 29 countries and caused more than 900 fatalities. Based on the concept of chemical genetics, we screened 50,240 structurally diverse small molecules from which we identified 104 compounds with anti-SARS-CoV activity. Of these 104 compounds, 2 target the SARS-CoV main protease (M(pro)), 7 target helicase (Hel), and 18 target spike (S) protein-angiotensin-converting enzyme 2 (ACE2)-mediated viral entry. The EC(50) of the majority of the 104 compounds determined by SARS-CoV plaque reduction assay were found to be at low micromolar range. Three selected compounds, MP576, HE602, and VE607, validated to be inhibitors of SARS-CoV M(pro), Hel, and viral entry, respectively, exhibited potent antiviral activity (EC(50) < 10 microM) and comparable inhibitory activities in target-specific in vitro assays. 相似文献
100.
Larsen SD Fisher PV Libby BE Jensen RM Mizsak SA Watt W Ronk WR Hill ST 《The Journal of organic chemistry》1996,61(14):4725-4738
An investigation of the scope and mechanism of a new synthesis of cyclopentenes from 3,6-dihydro-2H-thiopyrans is described. Alkyl halides substituted with an electron-withdrawing group in the alpha-position were reacted with sodium thiosulfate, yielding the corresponding Bunte salts, which could be transformed to reactive thiocarbonyl compounds by elimination of the elements of bisulfite with mild base treatment. In situ trapping by 1,3-dienes afforded in good yields a variety of 3,6-dihydro-2H-thiopyrans substituted with electron-withdrawing groups at the 2-position. Exposure of these cycloadducts to strong base at low temperature effected a novel ring contraction, affording 2-(methylthio)-3-cyclopentenes after quenching with methyl iodide. The level of diastereoselectivity exhibited during the generation of these cyclopentenes was found to be dependent on the nature of the electron-withdrawing group at the 2-position of the dihydrothiopyran as well as the substitution pattern originally present in the diene component. In some cases, reducing the temperature during the ring contraction resulted in the isolation of good yields of vinyl cyclopropanes of high isomeric purity. With one substrate, highly diastereoselective rearrangement of a vinyl cyclopropane to a cyclopentene was unambiguously demonstrated, suggesting that this might be a key feature of the overall ring contraction mechanism. 相似文献