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31.
D.R. Bates 《Chemical physics letters》1982,89(4):294-296
A plot of the measured electron—ion recombination coefficient against the number density of ambient ammonia shows an unexpectedly early fall which, it is suggested, may be due to the collisional coupling between the dissociative states and the other states being weakened by the growth in the clustering. 相似文献
32.
MoN and MoO molecules produced in a hollow cathode discharge have been trapped in Ne, Ar, and Kr matrices at 4.2 and 13 K and investigated by optical spectroscopy. Bands attributed to MoN were identified in the red and blue spectral regions and assigned by comparison with gas phase results to the A4π → X4Σ? (a) and B4Σ → X4Σ? (a) transitions, respectively. The ground state of Mo14N has been identified as 4Σ? with ωe = 1040 cm?1 in an Ar matrix. Absorptions assigned to MoO in the red spectral region form the (0-0) and (1-0) bands of at least one electronic transition, but could not definitely be correlated with the gas phase results. The ground state vibrational frequency for Mo16O in an Ar matrix is 893.5 cm?1. Additionally, Mo2 absorptions centered at 19 305 cm?1 were shown to be part of a vibrational progression with an average spacing of 181 cm?1. 相似文献
33.
R.H.T. Bates 《Physics Reports》1982,90(4):203-297
The many methods suggested and (some of them) tried out experimentally and/or observationally for imaging celestial objects through the Earth's atmosphere are reviewed. Their theoretical and physical bases are examined. Most attention is paid to Labeyrie's speckle interferometry and its several extensions devised during the past decade-astrophysical results obtained with the aid of these techniques are listed. Other forms of optical interferometry are discussed, as are related techniques in radio astronomy and ultrasonics. 相似文献
34.
35.
MCl5 (M = Nb, Ta) reacts with 2 equivalents of Me3SiNHCMe3 to give [M(NCMe3)Cl3(NH2CMe3)] from which [M(NCMe3)Cl3(PMe3)2] is obtained on addition of PMe3. One equivalent of Me3SiNHCMe3 reacts with MCl5 in the presence of 3 equivalents of PMe3 to give [M(NCMe3)Cl3(PMe3)2] and PMe3HCl. MCl5 reacts with excess RNH2 (R = CMe3, CHMe2, CH2Me) to give [M(NR)(NHR)Cl2(NH2R)] and 3 equivalents of RNH3Cl. One equivalent of alcohol replaces the amido ligand in [M(NCMe3)(NHCMe3)Cl2(NH2CMe3)] to give [M(NCMe3)(OR)Cl2(NH2CMe3)]2 (M = Nb, R = OCMe3; M = Ta, R = OEt). The structure of [Ta(NCMe3)(μ-OEt)Cl2(NH2CMe3)]2 was determined by single-crystal X-ray diffraction methods. Crystals are triclinic, space group P with a = 9.900(5), b = 10. 161(17), c = 9.017(6) Å and α = 103.91(8), β = 97.77(4), γ = 64.40(7)°. The structure was solved by Patterson and Fourier methods and refined to an R value of 0.062 for 1319 observed data. The TaNimido and TaNamino bond lengths are 1.70(2) Å and 2.28(2) Å, respectively; the bridging TaO bond lengths are 2.01(2) Å and 2.32(2) Å, the longer one lying trans to the imido function. 相似文献
36.
G. R. Bates 《Journal of Optimization Theory and Applications》1978,24(4):639-649
Lower closure theorems are proved for optimal control problems governed by ordinary differential equations for which the interval of definition may be unbounded. One theorem assumes that Cesari's property (Q) holds. Two theorems are proved which do not require property (Q), but assume either a generalized Lipschitz condition or a bound on the controls in an appropriateL
p-space. An example shows that these hypotheses can hold without property (Q) holding. 相似文献
37.
Molecular dynamics computer simulations are used to determine the self-diffusion coefficients for a Gay-Berne model mesogen GB (4.4,20,1,1) in the isotropic, nematic and smectic A phases along two isobars. The values of the parallel and perpendicular diffusion coefficients, D(parallel) and D(perpendicular), are calculated and compared in the different phases. For the phase sequence isotropic-smectic A, D(perpendicular)*> or =D(parallel)* over the whole smectic A range with the ratio D(parallel)*/D(perpendicular)* decreasing with decreasing temperature. At a higher pressure, a nematic phase is observed between these two phases and we find that D(parallel)*>D(perpendicular)* throughout the nematic region and the inequality D(parallel)*>D(perpendicular)* remains on entering the smectic A phase. However, the ratio D(parallel)*/D(perpendicular)* decreases with decreasing temperature within the smectic A range and eventually this ratio inverts such that D(perpendicular)*>D(parallel)* at low temperatures. The temperature dependence of the parallel diffusion coefficient in the smectic A phase for this model mesogen is compared to that predicted by a theoretical model for diffusion subject to a cosine potential. 相似文献
38.
39.
Peter W. Bates Kening Lu Chongchun Zeng 《Transactions of the American Mathematical Society》2000,352(10):4641-4676
Let be a compact manifold which is invariant and normally hyperbolic with respect to a semiflow in a Banach space. Then in an -neighborhood of there exist local center-stable and center-unstable manifolds and , respectively. Here we show that and may each be decomposed into the disjoint union of submanifolds (leaves) in such a way that the semiflow takes leaves into leaves of the same collection. Furthermore, each leaf intersects in a single point which determines the asymptotic behavior of all points of that leaf in either forward or backward time.
40.
Constructions introduced by Dirac for singular Lagrangians are extended and reinterpreted to cover cases when kernel distributions are either nonintegrable or of nonconstant rank, and constraint sets need not be closed. 相似文献