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91.
OK Yoon WG Hwang JC Choe MS Kim 《Rapid communications in mass spectrometry : RCM》1999,13(14):1515-1521
A technique to investigate photodissociation kinetics on a nanosecond time scale has been devised for molecular ions generated by multiphoton ionization (MPI) using mass-analyzed ion kinetic energy spectrometry. The branching ratio or rate constant has been determined for the photodissociation of the n-butylbenzene, bromobenzene, iodobenzene, and aniline molecular ions generated by MPI at 266 nm. The ion internal energies have been estimated by comparing the measured kinetic data with the previous energy dependence data. The analysis has shown that only those molecular ions generated by two-photon ionization contribute to the photodissociation signals. Around half of the available energy has been found to remain as molecular ion internal energy in the two-photon ionization process. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
92.
N. Jalarvo N. Aliouane H. N. Bordallo C. J. Milne J. R. Veira D. N. Argyriou 《The European physical journal. Special topics》2007,141(1):69-72
Quasielastic neutron scattering (QENS) has been used to
investigate the dynamical behaviour of H2O in the
superconductor Na0.28CoO2 .yH2O. The
measurements were obtained at room temperature for a molar
concentration of water, y = 1.3. From the analysis of the
Q-dependence of the EISF and the line-width we found that the water
dynamics can be well described by rotational motion that likely
correspond to re-orientation of the H2O molecule. We were also
able to define a rotational correlation time of τ= 1.85 ps. 相似文献
93.
The figure of merit for the electron optical performance of carbon-nanotube (CNT) electron sources is presented. This figure is given by the relation between the reduced brightness and the energy spread in the region of stable emission. It is shown experimentally that a CNT electron source exhibits a highly stable emission process that follows the Fowler-Nordheim theory for field emission, fixing the relationship among the energy spread, the current, and the radius. The performance of the CNT emitter under realistic operating conditions is compared with state-of-the-art electron point sources. It is demonstrated that the reduced brightness is a function of the tunneling parameter, a measure of the energy spread at low temperatures, only, independent of the geometry of the emitter. 相似文献
94.
Diffractive optics are applied to six-wave mixing processes to provide a single optic approach to attaining the required, relatively complex, phase-matching geometry to discriminate against lower-order nonlinear responses. The diffractive optics were designed specifically for broad-bandwidth operation and passive phase locking of the appropriate pulse pairs for use in femtosecond two-dimensional Raman studies of the dynamic structure of liquids. The fifth-order signal was studied in liquid CS>(2); two different colors were used for the excitation and the probe to reduce background scatter, as were two different phase-matching geometries with different degrees of suppression of cascaded third-order processes. 相似文献
95.
C.J. Fraser Lecturer J.S. Milne Lecturer 《International Journal of Heat and Fluid Flow》1980,2(4):165-173
The results of an experimental investigation of four different, incompressible, transitional boundary layer situations are presented. The experiments were carried out in zero pressure gradient conditions and transition was initiated from two- and from three-dimensional provoking agents.
The measurements of transitional intermittency from two-dimensional tripping agents showed a trend consistent with that reported elsewhere in the literature, with the development of mean and fluctuating component velocity profiles and local skin friction coefficient exhibiting approximate similarity through the transition region.
Disturbance frequency and spread angles for turbulent wedge growth behind isolated roughness elements were similar to those reported by others.
Computer predictions using a transition model based on the present correlations show reasonable agreement with the data. 相似文献
96.
Stephen C Milne 《Journal of Combinatorial Theory, Series A》1982,33(1):36-47
Let Vn(q) denote the n-dimensional vector space over the finite field with q elements, and Ln(q) be the lattice of subspaces of Vn(q). Two rank- and order-preserving maps from Ln(q) onto the lattice of subsets of an n-set are constructed. Three equivalent formulations of these maps are given: an inductive procedure based on an elementary combinatorial interpretation of a well-known pair of difference equations satisfied by the Gaussian coefficients [], a direct set-theoretical definition, and, a direct definition involving a certain pair of modular chains in Ln(q). The direct set-theoretical definition of one of these maps has already been given by Knuth. Knuth's map, however, may be systematically discovered by means of the inductive procedure and the direct lattice-theoretic definition shows how it can be generalized. As a further application of the pair of difference equations satisfied by [], a direct-combinatorial proof of an identity of Carlitz that expands Gaussian coefficients in terms of binomial coefficients has been formulated. 相似文献
97.
Computer programs have been written for interactive, conversational searching through the accumulated files of the 'Mass Spectrometry Bulletin' published by the Mass Spectrometry Data Centre (MSDC). This family of programs is available for use as a part of the NIH/EPA Chemical Information System on a commercial computer network. 相似文献
98.
Lysozyme and immune bacteriolysis 总被引:4,自引:0,他引:4
99.
D.C. Colley S.S. Huq M. Jobes J.B. Kinson J. Milne P.M. Watkins I.S. Hughes J.W.P. McCormick R.M. Turnbull 《Nuclear Physics B》1974,69(2):205-219
Data are presented on a high mass resonance produced in 10 GeV/c K+p interactions. The mass and width of the resonance, determined by a maximum likelihood fit to the pπ+ spectrum in the final state K+pπ+π?, are 1895±15 MeV/c2230±50 MeV/c2 respectively. The differential cross sections, dσ/dt, for the quasi two-body final states K1(890)Δ(1236) and K1(890)Δ(1900) are well described by the one pion exchange model. In addition the moments of the Gottfried-Jackson angular distribution of the pπ+ system agree with those computed from on-shell π+p elastic scattering data. We conclude that the two final states are produced mainly by π exchange and associate the structure observed in the moments up to NH(6,0) in the 1900 MeV region with the Regge recurrence of the Δ(1236). The dominant decay mode of the resonance is Δ++(1900)→pπ+ but decays to pπ+π0 and nπ+π+ are also observed. Cross sections are determined for the production of the quasi two-body final states K1(890)Δ(1236), K1(890) Δ(1900), K1(1420)Δ(1236) and K1(1420)Δ(1900). 相似文献
100.
Tyan and Thomas (J. Multivariate Anal.5 (1975), 227–235), have given a characterization of a class of bivariate distributions which yields, as a special case, a characterization of a class of bivariate Poisson distributions. In this paper we develop an analogous characterization of a class of bivariate Poisson processes and give some properties and examples of such processes. 相似文献