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61.
A previous publication1 has rationalized the thermal analyses of zeolite A samples, containing sodium and strontium ions, on the basis of X-ray structural evidence2. This paper examines the thermogravimetric (TG), thermomechanical (TMA) and differential thermal analyses (DTA) of zeolite A containing sodium, cobalt and nickel ions. The results are linked to the structural analyses of Amaro 3 and, in the case of nickel, to the spectroscopic studies of Klier and Ralek4. 相似文献
62.
The main computational burden in pivoting methods for determining all vertices of a convex polytope appears to be in testing pairs of vertices for adjacency. We show how, in the Dyer-Proll algorithm, this burden can be reduced by a new labelling of the search tree and by a mechanism for removing redundant branches. We also introduce an implementation strategy, the barred pivot strategy, which further improves the algorithm's performance. 相似文献
63.
W. S. Lyon E. Ricci L. C. Bate F. F. Dyer 《Journal of Radioanalytical and Nuclear Chemistry》1973,15(1):399-404
The forensic activation analyst must often evaluate his own results as they relate to certain legal or moral situations, since
investigative officers, and courts of law are not usually competent to make judgements of the validity or meaning of scientific
data. In providing scientific evidence in court, two criteria for criminal identification must be met: (1) suspect's sample
should be similar to sample found at the scene of the crime, (2) samples relared to other people in the same statistical population
should not generally match that found at the crime site. When two or more specimens are submitted for comparison by NAA they
will usually fall into one of three classes: (a) materials about which we have partial or inconclusive data, (c) materials
with an excellent analytical data background. Ideally all cases would fall in category c; in practice, very few. Some examples
of cases and/or situations that fall into these three categories in both individual and corporate investigations are given.
Research sponsored by U.S. Atomic Energy Commission under contract with Union Carbide Corporation. 相似文献
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66.
This paper discusses the rationale for the use of additive models involving multiple objectives as approximations to normative analyses. Experience has shown us that organizations often evaluate important decisions with multiple objective models rather than reducing all aspects of the problem to a single criterion, dollars, as many normative economic models prescribe. We justify this practice on two grounds: managers often prefer to think about a problem in terms of several dimensions and a multiple objective model may provide an excellent approximation to the more complex normative model. We argue that a useful analysis based on a multiple objective model will fulfill both conditions—it will provide insights for the decision maker as well as a good approximation to the normative model. We report several real-world examples of managers using multiple objective models to approximate such normative models as the risk-adjusted net present value and the value of information models. The agreement between the approximate models and the normative models is shown to be quite good. Next, we cite a portion of the behavioral decision theory literature which establishes that linear models of multiple attributes provide quite robust approximations to individual decision-making processes. We then present more general theoretical and empirical results which support our contention that linear multiple attribute models can provide good approximations to more complex models. 相似文献
67.
Two different square-root filters, one obtained by Potter and the other employing Householder transformations, are extended to include process noise. The relative numerical accuracy of various sequential filters is explored with several examples.This paper presents the results of one phase of research performed at the Jet Propulsion Laboratory, California Institute of Technology, under NASA Contract No. NAS 7-100. 相似文献
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69.
Elizabeth Dyer Richard A. Dunbar 《Journal of polymer science. Part A, Polymer chemistry》1970,8(3):629-640
Phosphorus-containing polyurethans of the formula were prepared by interfacial polymerization of 1,4-butanebischloroformate and p-xylylene-α, α-bischloroformate with bis(m-aminophenyl)alkylphosphine oxides. The polymers had number average molecular weights up to 8600. A test of the stability to alkali of one of the polymers (R?CH3, X?1,4-C6H4) showed it to be as resistant as nonphosphorus analogs, and a film of this polymer exhibited self-extinguishing properties. Thermal degradation of the phosphorus polymers, which began at approximately 230°C, occurred by an initial first-order process, releasing chiefly carbon dioxide. The energies of activation for the maximum rates of weight loss were 31–37 kcal/mole. 相似文献
70.
The cross section for the reaction 12C(α, γ)16O has been measured for a range of c.m. energies extending from 1.41 MeV to 2.94 MeV, by using 12C targets of high isotopic purity, large NaI(T1) crystals, and the time-of-flight technique for the suppression of prompt neutron background and time-independent background. Gamma-ray angular distributions were measured at c.m. energies of 2.18, 2.42, 2.56 and 2.83 MeV. By means of theoretical fits, which include the coherent effects of the 1? states of 16O at 7.12 MeV, 9.60 MeV, and those at higher energies, the electric-dipole portion of the cross section at astrophysically relevant energies has been determined. A three-level R-matrix parametrization of the data yields an S-factor at Ec.m. = 0.3 MeV, S(0.3 MeV) = 0.14+0.14?0.12 MeV · b. A “hybrid” R-matrix optical-m parameterization yields S(0.3 MeV) = 0.08+0.05?0.04 MeV · b. This S-factor is of crucial importance in determining the abundances of 12C and 16O at the end of helium burning in stars. 相似文献