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251.
Charles Brown R.Harry Cragg Tim J. Miller David ON Smith 《Journal of organometallic chemistry》1985,296(3):c17-c18
In suitable cases, VT 13C NMR can provide a rapid and reliable method for obtaining activation parameters ΔH★ and ΔS★ for restricted rotation about the B N bond in aminoboranes. 相似文献
252.
253.
The Green's function for the time-dependent solar collector problem is derived and examined. It is found that the influence of a point source of irradiance propagates with the speed of the heat transfer fluid. This result contradicts some earlier work.An analytical expression is derived for the output fluid temperature in terms of the irradiance as a function of position and time. Fluctuations in ambient and input fluid temperatures are also considered. 相似文献
254.
255.
Highly porous interpolymer ion-exchange membranes of poly(styrene sulfonic acid) and poly(vinylidene fluoride) have been investigated under pressure filtration with KCI, Na2SO4, erythrosin, and bovine serum albumin as solutes in the feed solution. The rejection of the ionic solutes is governed by a Donnan exclusion of electrolyte from the membrane phase. A model for the transport behavior is proposed that includes both diffusive and convective salt transport. The calculated rejections agree adequately with the observed data. 相似文献
256.
Prasad V. S. Ika Harry L. Frisch Gary R. Walters Paul C. Painter Kurt C. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1986,24(9):2297-2309
The synthesis of crosslinked polydiacetylene [poly4ECMU (a polydiacetylene with ethoxy carbonyl methylene urethane substitution): where R = ? (CH2)4OCONHCH2COOCH2CH3] was carried out utilizing its polar and flexible substituent groups. Polydiacetylene was crosslinked by the formation of allophanate linkages utilizing urethane groups in the substituent groups of the polydiacetylene. Two-component IPNs of polydiacetylene [poly4BCMU (a polydiacetylene with butoxy carbonyl methylene urethane substitution): where R = ? (CH2)4OCONHCH2COO(CH2)3CH3] and an epoxy resin (diglycidyl ether of Bisphenol A) were synthesized. Two-component IPNs of poly4ECMU with the above epoxy resin were also synthesized. For the first time, two-component stiff-backbone IPNs of two different kinds of polydiacetylene (poly4BCMU and polyECMU) and a three-component IPN of poly4BCMU, poly4ECMU, and the epoxy resin were synthesized. IPNs with fewer allophanate linkages were also made in order to examine morphological differences between them. The glass transition behavior of these networks was studied using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) by means of a Rheovibron. 相似文献
257.
Harry T. Hsu 《BIT Numerical Mathematics》1976,16(4):378-382
In this paper we first show that the Shen and Peterson System [1] is a combination of two Fibonacci buddy systems [2, 3]. Then we present a generalized Shen and Peterson system. The generalized system has more flexibility in the generation of fixed size blocks. For the generalized system, the algorithm for the determination of the buddy of any released block is easier than that of the Shen and Peterson system. 相似文献
258.
Harry Dym 《Israel Journal of Mathematics》1977,27(1):21-48
LetP
T denote projection onto the space of entire functions of exponential type ≦T which are square summable on the line relative to a measuredΔ and letG denote multiplication by a suitably restricted complex valued function,g. For a reasonably large class of measuresdΔ, which includes Lebesgue measuredγ, it is shown that trace {(P
TGPT)n−PTGnPT} tends boundedly to a limit asT↑∞ and that the limit isindependent of the choice ofdΔ within the permitted class. This extends the range of validity of a formula due to Mark Kac who evaluated this limit in
the special casedΔ=dγ using a different formalism. 相似文献
259.
Harry J.T. Preston Joyce J. Kaufman Jaime Keller J.Bryan Danese John W.D. Connolly 《Chemical physics letters》1976,37(1):55-59
The multiple-scattering Xα model has been applied to the sequence of boron trihalides BX3 where X = F.C1. Br, and I. Transition state calculations show good agreement with the experimental ionization potentials measured by photoelectron spectra. 相似文献
260.
Harry J. Lipkin 《Physics letters. [Part B]》1982,109(4):326-330
Flavor symmetry selection rules provide unambiguous signatures for glueball decays at masses above 1500 MeV where many channels are open. For example, a 2++ glueball should decay into ππ, K, ηη, η'η', ωω, ?? and ψψ, but not into K1 nor ηη'. A quarkonium or a four-quark state cannot go into all channels allowed for a glueball; at least one is OZI-forbidden for any choice of flavors. But any quarkonium state that goes to K should also go to K1 and ηη'. These selection rules are shown to be stable against SU(3) symmetry breaking. 相似文献