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121.
122.
The ketonization of vinyl alcohol in aqueous solution has been studied by means of ab initio calculations, using the STO -3G basis set. The intervention of a chain of two water molecules reduces dramatically the potential barrier. This result agrees with experimental facts. 相似文献
123.
We introduce a full scale of Lorentz-BMO spaces BMO
L
p,q
on the bidisk, and show that these spaces do not coincide for different values ofp andq. Our main tool is a detailed analysis of Carleson's construction in [C].
The first author gratefully acknowledges support by the LMS and Proyecto BFM2002-04013. The second author gratefully acknowledges
support by EPSRC and by the Nuffield Foundation. 相似文献
124.
Oscar Chisini 《Rendiconti del Circolo Matematico di Palermo》1916,42(1):59-64
An improvement of the uniqueness theorem of Wintner for the differential equationx (n)(t)=f(t, x) is given. 相似文献
125.
Oscar Cantoni 《Fresenius' Journal of Analytical Chemistry》1925,67(1-2):33-34
Zusammenfassung Die alte Berzelius-Methode zur Alkalibestimmung in Silikaten wird bedeutend vereinfacht, wenn man nach dem Flusss?ure-Aufschluss
die Schwefels?ure vollst?ndig verjagt, die Sulfate schwach glüht, und die Masse mit heissem Wasser auszieht. 相似文献
126.
127.
128.
Oscar Liebreich 《Fresenius' Journal of Analytical Chemistry》1865,4(1):173-176
Ohne ZusammenfassungVom Verfasser mitgetheilt. 相似文献
129.
We study the macroscopic mechanical behavior of materials with microscopic holes or hard inclusions. Specifically, we deal with the effective elastic moduli of composites whose microgeometry consists of either soft or hard isolated inclusions surrounded by an elastic matrix. We approach this problem by taking the stiffness of the inclusion phase to be a complex variable, which we eventually evaluate at the soft or hard limits. Our main result states that there is a certain class of non-physical, negative-definite values of the elastic moduli of the inclusion phase for which the effective tensor does not have infinities or become otherwise singular.We present applications of this result to the estimation of effective moduli and to homogenization theorems. The first application involves using complexanalytic methods to obtain rigorous and accurate bounds on the effective moduli of the high-contrast composites under consideration. We also discuss the variational estimates of Rubenfeld & Keller, which yield a complementary set of bounds on these moduli. The best bounds are given by a combination of the analytical and variational results. As a second application, we show that certain known theorems of homogenization for materials with holes are simple consequences of our main result, and in this connection we establish corresponding new theorems for materials with hard inclusions. While our rederivation of the homogenization theorems for materials with holes can be closely related to other known constructions, it appears that certain elements provided by our main result are essential in the proof of homogenization for the hard-inclusion case. 相似文献
130.
Current work has evaluated uncertainty associated to quantification of several organic compounds present in particulate matter of atmospheric aerosols, setting out the stages of analytical procedure that contribute most to the global uncertainty. Several sources of uncertainty have been identified, which were clustered into five main contributions: sampling, extraction, clean-up, derivatization and analysis. A discussion of the main contributions to the overall uncertainty is reported, allowing authors to locate the largest ones and plan future improvements. Combined uncertainties ranged between 10-18% (alkanes), 12-16% (PAHs), 10-18% (alcohols) and 9-21% (acids). The analytical procedure was validated by analysing a standard reference material (SRM1649a, urban dust). Also, the proposed method was applied to the analysis of four samples of particulate matter. 相似文献