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101.
A. Simonits S. Jovanović F. De Corte L. Moens J. Hoste 《Journal of Radioanalytical and Nuclear Chemistry》1984,82(1):169-179
When making use of some single comparator or absolute standardization methods in reactor neutron and in epicadmium neutron activation analysis, the knowledge of the effective resonance energy (
) is essential to correct for the effect of the nonideal epithermal flux distribution on the analysis result.
can be calculated from neutron resonance data, but when these are incomplete, not accurate or even not known at all, experimental determination should be considered. Such a method, providing both
and the resonance integral to 2200 ms–1 cross-section ratio (QO), is described in this paper. Results are given for 11 isotopes. 相似文献
102.
S. De Rossi E. Iguchi M. Schiavello R. J. D. Tilley 《Reaction Kinetics and Catalysis Letters》1977,6(2):201-208
The oxidation of propene was studied on several tungsten oxides which contained small amounts of Ti, Ta, Nb and Sn. Only the Sn-containing specimen was found to be selective in the conversion of propene to acrolein. The catalytic results are correlated with crystal structures determined by electron microscopy.
, Ti, Ta, Nb Sn. , , Sn, . , .相似文献
103.
J.C.M. De Wit W.H. Van Riemsdijk M.M. Nederlof D.G. Kinniburgh L.K. Koopal 《Analytica chimica acta》1990
Humic substances are characterized by a variable electric potential and by a variety of binding sites leading to chemical heterogeneity. Binding of ions to these substances is influenced by both factors. A methodology based on acid—base titrations at several salt levels is presented that allows for the assessment of an appropriate electrostatic double-layer model and the intrinsic proton affinity distribution. The double-layer model is used for the conversion of pH to pHS for each data point, where HS is the proton concentration in the diffuse layer near the binding site. It is shown that with an appropriate double-layer model the proton binding curves at different salt levels converge into one “master curve” when plotted as a function of pHS. The intrinsic proton affinity distribution can then be derived from the “master curve” using the LOGA method. A rigorous analysis of metal binding to humic substances is complex and in practice is not feasible. Under two different (simplifying) assumptions, namely fully coupled and uncoupled binding, it is shown how intrinsic metal ion affinity distributions can be obtained. Model calculations show that apparent metal ion affinity distributions do not resemble the intrinsic metal ion affinity distribution. 相似文献
104.
Abstract-2-Methoxy-4-oxazolidone structures are assigned to the photocycloexpansion products of the substituted 2,4-azetidindiones on the basis of mass spectral evidence. A discussion is given of the mass spectra of 2-methoxy-4-oxazolidones and of their hydrolysis products, the 2-hydroxy-4-oxazolidones and the ring opened substituted 2-hydroxy-N-formyl acetamides. Ring and chain forms, when both isolated, yield completely different mass spectra, indicating that no rapid tautomeric equilibrium is established in the gas phase. 相似文献
105.
The isomeric chlorosulfones 3, 4 and 5 are prepared by 1,4-addition of sulfonyl chlorides to isoprene, Dehydrohalogenation affords the corresponding 2- and 3-methylbutadienyl sulfones in a configuration which is dependent on the configuration of the chlorosulfone. Pure Z-2-methylbutadienyl sulfones 1 are obtained by displacement of primary halides by the Z-sulfinate anion 2. The Z-sulfones 1 are isomerized to E/Z-mixtures. The E/Z-mixtures are separated into their components and the configuration of the isomers is established by the NMR-NOE technique. 相似文献
106.
Designs, Codes and Cryptography - In this paper, we complete the classification of the caps in $$\text{ PG }(n,q)$$ having the property that on every tangent line L, there exists a unique point... 相似文献
107.
De Sujit Kumar Bhattacharya Kousik 《Journal of Optimization Theory and Applications》2022,192(2):598-627
Journal of Optimization Theory and Applications - This article deals with an economic production quantity (EPQ) model with deterioration under the effect of environmental pollution in fuzzy... 相似文献
108.
Ambiguous loci of the metric projection onto compact starshaped sets in a Banach space 总被引:1,自引:0,他引:1
LetE be a real Banach space andL(E) the family of all nonempty compact starshaped subsets ofE. Under the Hausdorff distance,L(E) is a complete metric space. The elements of the complement of a first Baire category subset ofL(E) are called typical elements ofL(E). ForXL(E) we denote by
the metrical projection ontoX, i.e. the mapping which associates to eachaE the set of all points inX closest toa. In this note we prove that, ifE is strictly convex and separable with dimE2, then for a typicalXL(E) the map
is not single valued at a dense set of points. Moreover, we show that a typical element ofL(E) has kernel consisting of one point and set of directions dense in the unit sphere ofE. 相似文献
109.
110.
Abe K Abt I Ahn CJ Akagi T Ash WW Aston D Bacchetta N Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Dasu S 《Physical review letters》1995,74(9):1512-1516