排序方式: 共有31条查询结果,搜索用时 15 毫秒
21.
We numerically investigate the trade-offs between the dispersion properties,coupling efficiency,and geometrical constraints in dual-wire (twin-lead) terahertz (THz) waveguides.In particular,we show that their inherent linearly polarized quasi-transverse electromagnetic (TEM) modes exist for waveguide transverse dimensions comparable with the wavelength,enabling significant end-fire coupling (>10%) for numericalaperture limited Gaussian beams while supporting a relatively low-dispersion propagation of below 0.5 ps 2 /m,as desired for short-pulse time-domain spectroscopy applications.Starting from the dual-wire structure,we also demonstrate that low-dispersion tapers can be designed to improve coupling efficiency. 相似文献
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Buyko A.M. Bidylo N.P. Chernyshev V.K. Demidov V.A. Garanin S.F. Kostyukov V.N. Kulagin A.A. Kuzyaev A.I. Mezhevov A.B. Mokhov V.N. Pavlovskiy E.S. Petrukhin A.A. Yakubov V.B. Yegorychev B.T. Canada J.W. Ekdahl C.A. Goforth J.H. King J.C. Lindemuth I.R. Reinovsky R.E. Rodriguez P. Smith R.C. Veeser L.R. Younger S.M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(2):145-154
In November 1992, the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF), Arzamas-16, Russia and the Los Alamos National Laboratory, Los Alamos NM, USA embarked on a historic effort to conduct a joint explosive pulse-power experiment. With the concurrence of the Ministry of Atomic Energy (Russia) and the Department of Energy (US), the two laboratories entered into a laboratory-to-laboratory collaboration in the areas of very high-energy pulse power and ultrahigh magnetic fields in order to explore problems of mutual scientific interest. The first experiment to be planned was an explosively powered, fast, high-current pulse-power system demonstration. The experiment used a flux compressor, inductive store, and high-current opening switch to demonstrate the feasibility of supplying many megajoules of electrical energy, on microsecond time scales, to high-energy density physics experiments. The experiment was conducted in Arzamas-16 on September 22, 1993 相似文献
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Ki Hwan Bae 《中国化学快报》2009,20(11):1321-1323
Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative(1),named davidianoside.The structure was elucidated on the basis of extensive physicochemical and spectroscopic analyses. 相似文献
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The TRIUMF Injector CryoModule (ICM) adapted two superconducting single cavities as the capture section for the low injecting energy of 100 keV electrons. Coupler kick induced beam deflection and projected emittance growth are one of the prime concerns of the beam stability, especially at low energies. In low energy applications, the electron velocity changes rapidly inside the cavity, which makes the numerical analysis much more complicated. The commonly used theoretical formulas of the direct integral or the Panofsky-Wenzel theorem is not suitable for the kick calculation of β<1 electrons. Despite that, the above mentioned kick calculation method doesn't consider injecting electron energy, the beam offset due to the coupler kick may not be negligible because of the low injection energy even if the kick is optimized. Thus the beam dynamics code TRACK is used here for the simulation of the power coupler kick perturbation. The coupler kick can be compensated for by a judicious choice of the coupler position in successive cavities from upstream to downstream. The simulation shows that because of the adiabatic damping by the following superconducting 9-cell cavity, even for the worst orbit distortion case after two capture cavities, the kick is still acceptable at the exit of the ICM after reaching 10 MeV. This paper presents the analysis of the transverse kick and the projected emittance growth induced by the coupler for β<1 electrons. The simulated results of the TRIUMF ICM capture cavities are described and presented. 相似文献
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全相关(TOCSY)技术可提供自旋网络中全部质子的接力信息,特别适用于具有若干独立自旋系统的大分子。本文在同核和异核相关中均用MLEV-17序列进行全面相关,并以一个三肽作为模型化合物为例说明该法的应用。 相似文献
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Jerry L. Atwood Ralph D. Priester Robin D. Rogers Larry G. Canada 《Journal of inclusion phenomena and macrocyclic chemistry》1983,1(1):61-69
Both title compounds were prepared by adding AlMe3 to a suspension of the appropriate crown ether in toluene, followed by reaction in a sealed tube. Both products were obtained in the form of extremely air-sensitive, colorless crystals. [AlMe3]3[dibenzo-18-crown-6] crystallizes in space group Pī, witha=8.898(4),b=11.848(5),c=19.060(6) Å, α=74.86(3), β=80.73(4), and γ=67.02(4)°. Refinement led to a final conventional weightedR value of 0.052 for 1800 reflections. [AlMe3]4[18-crown-6] belongs to space group Pbcn, witha=18.753(3),b=12.570(6), andc=15.095(6) Å. Refinement was taken toR w =0.064 for 1320 reflections. 相似文献
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D. H. Russell B. S. Freiser E. H. McBay D. C. Canada 《Journal of mass spectrometry : JMS》1983,18(11):474-485
The unimolecular dissociation reactions for [C7H7O]+ ions generated by fragmentation of a series of precursor molecules have been investigated. The metastable kinetic energy values and branching ratios associated with decarbonylation and expulsion of a molecule of formaldehyde (CH2O) from the [C7H7O]+ ions are interpreted as the hydroxybenzyl and hydroxytropylium [C7H7O]+ not interconverting to a common structure on the microsecond time-scale. In addition, similar measurements on protonated benzaldehyde, methylaryloxy and phenyl methylene ether [C7H7O]+ ions are interpreted as the dominant fraction of these decomposing ions having unique structures on the microsecond time-scale. These results are supported by experimental heats of formation calculated from ionization/appearance energy measurements. The experimental heats of formation are determined as: hydroxybenzyl ions, 735 kJ mol?1; hydroxytropylium ions, 656 kJ mol?1; phenyl methylene ether ions, 640 kJ mol?1; methylaryloxy ions 803 kJ mol?1. The combination of the results reported in this paper with previously reported experimental data for stable [C7H7O]+ ions (see Ref. 1, C. J. Cassady, B. S. Freiser and D. H. Russell, Org. Mass Spectrom.) is interpreted as evidence that the relative population of benzyl versus tropylium [C7H7O]+ ion structures from a given precursor molecule is determined by isomerization of the parent ion and not by structural equilibration of the [C7H7O]+ ion. 相似文献
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自交联型含氟丙烯酸酯共聚物的合成与表征 总被引:2,自引:0,他引:2
含氟丙烯酸酯;自交联;无皂乳液;接触角滞后 相似文献
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