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71.
Paul Van Der Meeren Jan Vanderdeelen Leon Baert 《Particle & Particle Systems Characterization》1994,11(4):320-326
Using a monodisperse PMMA dispersion, it was shown that light reflection at the sample cuvette walls may greatly influence the results of both static (SLS) and dynamic (DLS) light scattering experiments. Considering SLS, this reflection phenomenon mostly causes an overestimation of the scattered intensity at high scattering angles, which may give rise to the emergence of an additional, artificial peak in the lower region of the particle size distribution. On the other hand, the influcence of reflection on DLS measurements was shown to be particularly important in the upper region of the particle size distribution. The experimentally observed phenomena were explained from the basic principles of both particle sizing methods. Finally, it was shown that the disturbing effect of reflection could be avoided by modifying either the hardware or the software of the static and dynamic light scattering technique. 相似文献
72.
Paul W. Percival 《Hyperfine Interactions》1991,65(1-4):901-911
As “rapporteur” for the papers submitted to this conference in the general area of muonium chemistry, I briefly review the
major developments since μSR86, and attempt to show how the papers presented at μSR90 relate to each other and work published
in the intervening years. Some topics are discussed in more detail than others, reflecting my own interests and views on what
is of current importance. Nevertheless, I try to cover all current research in muonium chemistry. The major areas are: early
events following muon thermalization, including subsequent loss of muon polarization (the “missing fraction”); molecular structure
and dynamics, primarily of muonium-substituted free radicals: and reaction kinetics. 相似文献
73.
74.
The detailed characterization of multifunctional hybrid organosilazane/organosilylamine telechelic oligomers by IR and 1H, 13C and 29Si NMR spectroscopy in one and two dimenions has been undertaken. The specific multifunctional oligomers, comprising NH/NH2 or SiCl functionalities depending on the monomer feed-ratio, were prepared from mono- and di-functionally reacted dichlorodimethylsilane (DDS) and mono-, di-, tri- and tetra-functionally reacted ethylenediamine (EDA). Varying the feed-ratio afforded control of the microstructures of the oligomers and the preparation of oligomers with, in some cases, conterminously located silicon–chlorine (SiCl) groups. The combination of the NMR methods with the IR technique has enabled the detailed microstructural characterization of the oligomers and the identification of the functionalities therein. This approach and the knowledge gained from the DDS/EDA system has been applied to the microstructural characterization of other hybrid organosilazane/silylamine preceramic telechelic oligomers. 相似文献
75.
Penny Smith 《Journal of Mathematical Analysis and Applications》2002,275(2):693-710
In parts I, II, and III combined of this paper, we define a notion of viscosity solution for these equations and existence is proved by a Perron-like method. Here, in part I, we prove useful identities, and a maximum-like principle for smooth sub(super) solutions of the standard wave equation. We define a new potential theoretic (P) notion of solution, subsolution and supersolution, and a related potential type (P) Cauchy problem for semilinear second order hyperbolic equations. 相似文献
76.
The electron-stimulated desorption (ESD) of D− and H− ions from condensed D2O and H2O films is investigated. Three low-energy peaks are observed in the ESD anion yield, which are identified as arising from excitation of 2B1, 2A1 and 2B2 dissociative electron attachment (DEA) resonances. Additional structure is observed between 18 and 32 eV, which may be due to ion pair formation or to DEA resonances involving the 2a1 orbital. The ion yield resulting from excitation of the 2B1 resonance increases as the film is heated. We attribute the increase in the ion yield to thermally induced hydrogen bond breaking near the surface, which enhances the lifetimes of the excited states that lead to desorption. 相似文献
77.
78.
This paper examines the effect of infinitesimal functional variations in a rigid rotor He-HF potential surface on several different types of observables: inelastic cross sections, rate constants, and rotational energy level populations. The dynamics and kinetic observables studied were found to be sensitive to a large number of Legendre components of the potential with the region of highest sensitivity dependent upon the energy or temperature as well as the states related by the individual observable. Sensitivity to the entire surface tends to show a large degree of structure due to competition among sensitivities to the individual potential components. Significant information loss has been observed in the transition from microscopic to macroscopic observables. 相似文献
79.
80.
A Network Simulation of High-congestion Road-traffic Flows in Cities with Marine Container Terminals
James A. Pope Terry R. Rakes Loren Paul Rees Ingrid W. M. Crouch 《The Journal of the Operational Research Society》1995,46(9):1090-1101
Port cities where marine cargo terminals are located are generally near urban areas characterized by high-congestion road traffic. Changes in cargo traffic volumes into a marine terminal, or in the surrounding traffic arteries, which carry this traffic, can significantly affect the terminal's operations. Conversely, activity at the terminal can have an impact on the traffic levels and congestion for a considerable distance from the terminal. This paper demonstrates a methodology useful for studying the impact of road traffic flows on marine container terminals located in highly congested areas. This model was developed at the request of the Virginia Center for World Trade and was used to answer three planning questions in the port of Hampton Roads, Virginia, USA-what would be the impact of: opening a new section of interstate highway, a projected doubling of container traffic at one terminal, and a daily unit train in the vicinity of another terminal. The problem was made more challenging by limited data-collection funds. None the less, the model was deemed valid by a panel of traffic experts and officials from several major state and private agencies involved in marine traffic management. The model results were subsequently a factor in two major decisions related to terminal management. 相似文献