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101.
The temperature dependence of the polarized and depolarized Raman spectra of the ν2, ν4, ν6 and ν7 modes were measured for t-butyl chloride and the analogous group IVA trimethylmetal chrlorides (silicon, germanium and tin). Analysis of the lineshapes revealed that isotropic second moments and vibrational relaxation times for a given mode remained approximately constant through the series. This tranferability of relaxation parameters between molecules extended to modulation times calculated from the Kubo formalism. The above results are in contrast to earlier studies on molecules of dissimilar structure. They provide some preliminary evidence that the mechanism of vibrational relaxation may be the same for equivalent modes in members of the series. 相似文献
102.
Daniel G. Schwartz 《Fuzzy Sets and Systems》1985,17(2):153-165
This paper develops an interval-based approach to the concept of linguistic truth. A special-purpose interval logic is defined, and it is argued that, for many applications, this logic provides a potentially useful alternative to the conventional fuzzy logic.The key idea is to interpret the numerical truth value v(p) of a proposition p as a degree of belief in the logical certainty of p, in which case p is regarded as true, for example, if v(p) falls within a certain range, say, the interval [0.7, 1]. This leads to a logic which, although being only a special case of fuzzy logic, appears to be no less linguistically correct and at the same time offers definite advantages in terms of mathematical simplicity and computational speed.It is also shown that this same interval logic can be generalized to a lattice-based logic having the capacity to accommodate propositions p which employ fuzzy predicates of type 2. 相似文献
103.
A Celite-sodium borohyride column has been used to reduce micromole amounts of a variety of simple carbonyl compounds to the corresponding alcohol in fair to excellent yields. The procedure is relatively rapid and easy involving only the application of a hexane solution of the carbonyl compound to the column and collection of the effluent containing the alcohol. A column constructed in a melting point capillary suitable for the reduction of microgram amounts of carbonyls is also described. 相似文献
104.
105.
We discuss three methods of determining V(z), the lateral average (G = 0 Fourier component) of the atom-surface interaction, from the bound state spectrum found in beam scattering. One method uses the Rydberg-Klein-Rees technique, which yields the width of the potential (i.e., separation of classical turning points) as a function of energy. This method incorporates also the known asymptotic form V ~ ?C3z?3, whereC3 is derived from the polarizability and dielectric function of atom and solid, respectively. The second method uses a hybrid potential, constructed from a Morse potential with shifted zero of energy connected to the asymptotic form,?C3z?3, requiring continuity of V and . The third potential is a Lennard-Jones 3–9 interaction. Results are presented for H and He scattering from LiF and NaF. 相似文献
106.
Time-differential perturbed angular correlation was applied to measure the quadrupole coupling constants of111Cd (247 keV) at the In and Sn sites for rare-earth compounds of the series RIn3 and RSn3 that have the AuCu3 structure. Definitive evidence was found for Yb and Eu having lower valence states relative to the assumed value of +3 for the other rare earths. Measurements at liquid helium temperatures and pressures to 18.5 kbar indicate that the room temperature valencies of CeSn3, YbSn3, and YbIn3 have not changed.Work done under the auspices of the US Energy Research and Development Administration 相似文献
107.
108.
Niels Schwartz 《Archiv der Mathematik》1977,29(1):148-153
Ohne Zusammenfassung 相似文献
109.
Jinlong Cheng Matilda Fone Vijay N. Reddy Kenneth B. Schwartz Howard P. Fisher Bernhard Wunderlich 《Journal of Polymer Science.Polymer Physics》1994,32(16):2683-2693
The observation of chain conformation and mobility in polyethylene by solid-state 13C magic angle spinning (MAS) nuclear magnetic resonance (NMR) permits unambiguous identification and quantitative analysis of an intermediate phase. The carbon-carbon bonds in the intermediate phase adopt, on the average, an all-trans conformation and are more mobile than in the crystalline state (room temperature rate of reorientation ≈ 107 Hz). Comparisons of crystallinities by differential scanning calorimetry, wide-angle x-ray diffraction, and NMR support the high orientation of the intermediate phase and suggest a lower heat of fusion than for the crystals. Results from 13C spin-lattice relaxation and 1H spin diffusion show that the mass fractions are ≈ 20% and the domain sizes ≈ 36 Å. Both change with crystallization and annealing conditions. © 1994 John Wiley & Sons, Inc. 相似文献
110.