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541.
542.
Doyle Britton William W. Brennessel 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(8):o552-o556
The title p‐haloacetophenones, C8H7XO (X = Cl, Br and I), have different packing modes. The chloro compound contains H⋯O and H⋯Cl contacts, but no Cl⋯O contacts. The bromo compound and one polymorph (A) of the iodo compound are isomorphous, with significant X⋯O contacts [Br⋯O = 3.320 (4) Å and I⋯O = 3.374 (5) Å]. In the other polymorph (B) of the iodo compound, the I⋯O distance is 3.082 (4) Å. Both polymorphs contain C—H⋯π contacts; these contacts are shorter in A than in B. 相似文献
543.
D.J. Hoarty T. GuymerS.F. James E. GumbrellC.R.D. Brown M. HillJ. Morton H. Doyle 《High Energy Density Physics》2012,8(1):50-54
Heating of matter by proton beams produced by short pulse, laser-solid target interaction has been demonstrated over the last ten years by a number of workers. In the work described in this paper heating by a pulse of laser produced protons has been combined with high-resolution soft x-ray radiography to record the expansion of thin wire targets. Analysis of the radiographs yields material properties in the warm dense matter regime. These measurements imply initial temperatures in the experimental samples over a range from 14 eV up to 40 eV; the sample densities varied from solid to a tenth solid density. Assuming an adiabatic expansion after the initial proton heating phase isentropes of the aluminium sample material were inferred and compared to tabulated data from the SESAME equation of state library. The proton spectrum was also measured using calibrated magnetic spectrometers and radiochromic film. The accuracy of the technique used to infer material data is discussed along with possible future development. 相似文献
544.
Brahms N Newman B Johnson C Greytak T Kleppner D Doyle J 《Physical review letters》2008,101(10):103002
We have trapped large numbers of copper (Cu) and silver (Ag) atoms using buffer-gas cooling. Up to 3 x 10{12} Cu atoms and 4 x 10{13} Ag atoms are trapped. Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios of elastic to inelastic collision rates with He are >or=10{6}, suggesting Cu and Ag are favorable for use in ultracold applications. The temperature dependence of the Ag-3He collision rate varies as T;{5.8+/-0.4}. We find that this temperature dependence is inconsistent with the behavior predicted for relaxation arising from the spin-rotation interaction, and conclude that the Ag-3He system displays anomalous collisional behavior in the multiple-partial wave regime. Gold (Au) was ablated into 3He buffer gas, however, atomic Au lifetimes were observed to be too short to permit trapping. 相似文献
545.
This paper presents a method of identifying unknown parameter and force histories for nonlinear structures. The nonlinearities
treated are those that arise from large deflections and rotations and/or from material behavior in the form of elastic-plastic
and hyperelastic responses. The method is based on a sensitivity response approach in conjunction with a general finite element
program; it can determine multiple isolated force histories as well as multiple forces in the form of traction distributions.
Because it successfully allies a general finite element program with the inverse methods, there is (potentially, at least)
little restriction on the geometric and material complexity of the problems that can be handled. Experimental data from a
very flexible beam-like structure is used to demonstrate the attributes of the developed method. Both quasi-static and dynamic
tests are performed and evaluated. 相似文献
546.
547.
Michael P. Doyle William R. Winchester Marina N. Protopopova Paul Müller Grald Bernardinelli Doina Ene Sharokh Motallebi 《Helvetica chimica acta》1993,76(6):2227-2235
The synthesis and X-ray structure of the binuclear complex tetrakis[(4S)-4-phenyloxazolidin-2-one]-dirhodium(II) ([Rh2{(4S)-phox}4]) are reported. Structure-selectivity comparisons are made for typical metal carbene transformations, such as inter- and intramolecular cyclopropane formation, intermolecular cyclopropene formation and intramolecular C–H insertions of diazoacetates and diazoacetamides. The enantioselectivity achieved in the [Rh2{(4S)-phox}4]-catalyzed reactions is intermediate between that of [Rh2{(5S)-mepy}4] and [Rh2{(4R)-bnox}4], which were described previously (mepy = methyl 5-oxopyrrolidine-2-carboxylate; bnox = 4-benzyloxazolidin-2-one). In contrast to other catalyzed intermolecular cyclopropane formations, those using [Rh2{(4S)-phox}4] result preferentially in formation of the cis-cyclopropane. 相似文献
548.
James M. Doyle 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1965,16(4):527-531
Zusammenfassung Ausstrahlungsbedingungen für Lösungen der von der Zeit unabhängigen Gleichung der Bewegung der klassischen Elastizität, der wohlbekannten Sommerfeld-Bedingung ähnlich, werden untersucht. Die Bedingungen können physikalisch als ein nach aussen gerichteter Energiefluss dargestellt werden. Sie genügen auch, die Eindeutigkeit der Lösung aufzuzeigen. 相似文献
549.
Barla A Sanchez JP Haga Y Lapertot G Doyle BP Leupold O Rüffer R Abd-Elmeguid MM Lengsdorf R Flouquet J 《Physical review letters》2004,92(6):066401
High pressure 149Sm nuclear forward scattering experiments have been performed on the nonmagnetic semiconductor SmS. We present the first clear evidence that the closure of the insulating gap at p(Delta) approximately 2 GPa coincides with the appearance of magnetic order. The pressure-induced magnetic phase transition has some first order character and suggests that the Sm ions are nearly trivalent at p(Delta). A Gamma(8) quartet crystal field ground state with a value of approximately 0.5 micro(B) for the samarium magnetic moment is inferred from our results. Considerable magnetic short range order is observed above the ordering temperature inferred from macroscopic measurements. 相似文献
550.
We study the dynamics of single DNA molecules driven by an electric field into a stationary obstacle. These collisions are broadly classified as "hook" and "roll-off" events. We show that obstacle-induced electric field gradients stretch impacting DNA and thus greatly influence the hooking probability. Consequently, in addition to collision geometry, determination of the hooking probability depends on the Deborah number (De) for 0.5相似文献