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141.
In a graph, a chordless cycle of length greater than three is called a hole. Let be a {0, 1} vector whose entries are in one-to-one correspondence with the holes of a graphG. We characterize graphs for which, for all choices of the vector , we can pick a subsetF of the edge set ofG such that |F H| H (mod 2), for all holesH ofG and |F T| 1 for all trianglesT ofG. We call these graphsuniversally signable. The subsetF of edges is said to be labelledodd. All other edges are said to be labelledeven. Clearly graphs with no holes (triangulated graphs) are universally signable with a labelling of odd on all edges, for all choices of the vector . We give a decomposition theorem which leads to a good characterization of graphs that are universally signable. This is a generalization of a theorem due to Hajnal and Surányi [3] for triangulated graphs.This work was supported in part by NSF grants DMI-9424348 DMS-9509581 and ONR grant N00014-89-J-1063. Ajai Kapoor was also supported by a grant from Gruppo Nazionale Delle Ricerche-CNR. We also acknowledge the support of Laboratoire ARTEMIS, Université Joseph Fourier, Grenoble. 相似文献
142.
K. M. Michael S. C. Kapoor J. N. Mathur R. H. Iyer 《Journal of Radioanalytical and Nuclear Chemistry》1996,213(6):431-439
Four litres of Am solution containing 81.5 mg/l Am and 0.6 mg/l Pu could be purified by a two-step procedure involving solvent extraction and extraction chromatography with trilaurylamine. The final product contained a maximum concentration of 9 g/l Pu. 相似文献
143.
G. Singh I. P. S. Kapoor S. M. Mannan 《Journal of Thermal Analysis and Calorimetry》1996,46(6):1751-1761
Thermal and explosion characteristics of ring(mono) substituted arylammonium perchlorates (RSAP) are studied by DTA, impact and friction sensitivity measurements. Exothermic decomposition temperature (T d) from DTA curves and impact sensitivity data (h 50%) were found to be linearly related to the Hammett substituent constant (σ+,σ?) andpK a values of the corresponding arylamines. A reaction scheme, based on the formation of reaction intermediates during decomposition and explosion, accounting for the products, is proposed which, involves proton transfer as the rate determining process and evolution of ammonia. It seems that oxidation-reduction reactions between the arylamine/substituted benzene and HClO4 or its decomposition products cause explosion. 相似文献
144.
Mool C. Gupta Jaya D. Nath 《Journal of polymer science. Part A, Polymer chemistry》1980,18(2):709-712
The entropy of fusion of linear vinyl polymers [polypropylene, polystyrene, and poly(vinyl chloride)] having asymmetric carbon atoms was calculated on the basis of the rotational isomeric state model. The results are found to be in good agreement with the experimental entropies of fusion per bond for these polymers. 相似文献
145.
In this paper we present a comparative study of inelastic interactions of C12-Em and p-Em at 4·5 GeV/c per nucleon. The multiplicity distributions and their correlations have been studied. The results show a strong correlation of n
s onn
h in the case of C12-Em but not in the case of p-Em. It is also shown that the n
s increases with the increase of the projectile mass. The angular distribution of the target fragments in C12-Em shows a massive forward collimation. Comparison is also made in the pseudorapidity distribution of both C12-Em and p-Em, the result shows many interesting features. 相似文献
146.
Howard C. Clark Pramesh N. Kapoor Ian J. Mcmahon 《Journal of organometallic chemistry》1984,265(1):107-115
The reaction of PtCl2L (L = diphosphine) with the appropriate diphosphine L′ in ethanol followed by reduction with aqueous sodium borohydride leads to either disproportionation to give mixtures of the bis(diphosphine) complexes PtL2 and PtL′2 or to the formation of the mixed ligand complex PtLL′ depending on the diphosphines. Mixed ligand complexes are obtained when L=Ph2P(CH2)2PPh2, L′ = Ph2P(CH2PPh2cis-Ph2PCH CHPPh2, Ph2P(CH2)2AsPh2, Ph2- P(CH2)4PPh2, o-Ph2PC6H4PPh2; and L=(C6H11)2P(CH22P(C6H11)2, L′= Ph2P(CH2)PPh2, Ph2P(CH2)2PPh2cis-Ph2PCHCHPPh2, (2S,3S)-Ph2PCH- (CH3)CH(CH3)PPh2, (R)-Ph2PCH(CH3)CH2PPh2. When L=Ph2P(CH2)4PPh2 L′= Ph2P(CH23PPh2 or cis-Ph2PCHCHRPh2 the mixed ligand complexes are obtained but extensive disproportionation also occurs. 相似文献
147.
M. L. Kaul B. L. Kalsotra R. N. Kapoor 《Journal of Thermal Analysis and Calorimetry》1977,11(1):121-123
The TG curves of dipyridinium complexes of Ce(IV), Th(IV) and Zr(IV) have been reported. The mode of decomposition of the cerium and thorium complexes is broadly comparable but the decomposition of Zr complex shows some variation. 相似文献
148.
Cyclic voltammetric and differential pulse voltammetric characteristics of the oxidation reaction of ferrocene in acetonitrile solvent have been evaluated using a glassy carbon indicator electrode. The redox couple ferrocene/ferricinium ion approaches thermodynamic reversibility in acetonitrile medium in only a low concentration range. 相似文献
149.
Summary Phenyl acetic acid has been found to be a selective reagent for the estimation of zirconium. The acid gives a white crystalline precipitate which is quantitative between pH values of 3.00 to 5.40. As the composition of the precipitate varies somewhat, direct weighing is not possible and the compound is ignited to the oxide. The ions Be2+, Ca2+, Sr2+, Zn2+, Hg2+, Pb2+, Mg2+, Ni2+, and Co2+ do not interfere, whereas the ions Fe3+, UO2
2+, Cr3+, Ba2+, Au+, Al3+, V2O4
2+, Ti4+, Sn2+, and Ba2+ cause interferences in the estimation.
Part VI: See Z. analyt. Chem. 175, 29 (1960). 相似文献
Zusammenfassung Zur gravimetrischen Bestimmung von Zirkonium wird Phenylessigsäure empfohlen. Die weiße, kristalline Fällung ist im pH-Bereich 3,00–5,40 quantitativ. Infolge schwankender Zusammensetzung des Niederschlages ist eine direkte Wägung nicht möglich; er wird daher zum Oxid verglüht. Folgende Ionen stören nicht: Be2+, Ca2+, Sr2+, Zn2+, Hg2+, Pb2+, Mg2+, Ni2+ und Co2+; dagegen verursachen Fe3+, UO2 2+, Cr3+, Ba2+, Au+, Al3+, V2O4 2+, Ti4+, Sn2+ und Ba2+ Störungen bei der Bestim mung.
Part VI: See Z. analyt. Chem. 175, 29 (1960). 相似文献
150.
J. Uttamchandani S. K. Mehrotra A. M. Bhandari Prof. R. N. Kapoor 《Monatshefte für Chemie / Chemical Monthly》1977,108(3):735-741
Reactions of Aluminium isopropoxide with monofunctional bidentateSchiff bases, such as salicylidene-o-toluidine, salicylidene-p-toluidine, 2-hydroxy-1-naphthylmethylidene-p-toluidine and 2-hydroxy-1-naphthylmethylidene-p-toluidine in different stoichiometric ratios have yielded products of the type Al(OPr
i)2(SB), Al(OPr
i)(SB)2, and Al(SB)3 (whereSB
– is the anion of the correspondingSchiff base,SBH). Bifunctional tetradentateSchiff bases in 11 and 23 molar ratios [Al(OPr
i)3:SBH2] yielded insoluble derivatives of the type Al(OPr
i)SB and Al2(SB)3 (whereSB
– represents the anion of theSchiff baseSBH2 andSBH2=bis-salicylaldehyde-o-phenylene-diamine or bis-salicylaldehyde-p-phenylenediamine). The newSchiff base derivatives have been characterized by elemental analyses, infrared spectroscopy and molecular weight determinations. 相似文献