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51.
In this paper, we generalize the splitting off operation on graphs to binary matroids and investigate the relations between
the matroids resulting from this operation and the original binary matroids in terms of representation matrices, bases, rank
functions and connectivity. We also provide some interesting applications of this operation. 相似文献
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Todkary AV Dalvi R Salunke-Gawali S Linares J Varret F Marrot J Yakhmi JV Bhadbhade M Srinivas D Gejji SP Rane SY 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(1):130-138
Investigation on solvent-induced polymorphism in X-ray structures of 2-hydroxy-1,4-naphthoquinone (Lawsone) 1, is carried out. In protic methanol, 1 crystallizes in monoclinic space group P2(1)/c (1a) comprising of 2D hydrogen bonded network via cyclic dimers. In aprotic solvent such as acetone on the other hand, 1 exhibits orthorhombic space group Pna 2(1) (1b) and emerges with 1D catemeric chain. Solvent-induced topological isomerism of cyclic dimers and helical catemeric chains arising from (i) bifurcated intra- and inter molecular hydrogen bondings viz. O-H...O=C interactions between C(2) hydroxyl and C(1), C(4) carbonyls, (ii) C-H...O interactions viz. C(3)-H...O(1)C(1) have been discussed. A signal for radical in 1 at g = 2.0058 is signatured by EPR spectrum and it's oxime derivative viz. 2-hydroxy-4-naphthoquinone-1-oxime 2, in solid state shows biradical and monoradical formation with aggregation of dimer and monomer due to non-covalent hydrogen bonds. Zero field split parameters for 2 are estimated to be D = 215 G, Ex = 13 G, Ey = 47 G at 298 K. A half field signal at 77 K indicates triplet ground state. Frozen glass EPR of 2 resolves as regioregular dimeric-monomeric species showing hyperfine interactions with 1-oximino nitrogen in dimer A (14N) = 15.5 G]. 相似文献
54.
The quenching constants for the UO2+2 ion fluorescence by the Eu3+ ion in H2O, D2O, potassium formate and acetic acid media were determined by measuring the decrease in intensity of the 5050 Å fluorescence peak and the lifetime of the UO2+2 ion fluorescence. The energy transferred to the Eu3+ ion was found to be a small fraction of the energy lost by the UO2+2 ion by the non-radiative processes. The variations of the quenching constants of the UO2+2 ion and the fluorescence lifetimes were determined for different concentrations of potassium formate and acetic acid. These results indicate that the UO2+2 ion forms inner sphere complexes with the two ligands mentioned. 相似文献
55.
A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method has been developed for simultaneous determination of losartan potassium, ramipril, and hydrochlorothiazide. The three drugs were separated on a 150 mm × 4.6 mm i.d., 5 μm particle, Cosmosil C18 column. The mobile phase was 0.025 m sodium perchlorate–acetonitrile, 62:38 (v/v), containing 0.1% heptanesulphonic acid, pH adjusted to 2.85 with orthophosphoric acid, at a flow rate of 1.0 mL min−1. UV detection was performed at 215 nm. The method was validated for linearity, accuracy, precision, and limit of quantitation. Linearity, accuracy, and precision were acceptable in the ranges 35–65 μg mL−1 for losartan, 1.75–3.25 μg mL−1 for ramipril, and 8.75–16.25 μg mL−1 for hydrochlorothiazide. 相似文献
56.
It is known that a Markov map T of the unit interval preservesa measure µ, say, equivalent to Lebesgue measure, andthat almost every point of the interval has a forward orbitunder T that is uniformly distributed with respect to µ.In the opposite direction the main result of this paper statesthat there is a set of points having Hausdorff dimension 1 whoseforward orbits are in a certain sense very far from being sodistributed. 1991 Mathematics Subject Classification: 58F08,28A80. 相似文献
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Crystallization in the melt-quenched (MQ) and mechanically milled (MM) superionic systems has been thoroughly investigated using differential scanning calorimetry, X-ray diffraction and electrical conductivity measurements. It is observed that the two systems obey different crystallization processes. The conventionally melt-quenched samples exhibit only one crystallization peak near 112 °C, whereas, the mechanochemically synthesized samples show two well-separated crystallization peaks at Tcl∼75-97 °C and Tc2∼132±2 °C. The higher value of electrical conductivity in the mechanochemically synthesized samples (∼10−2 Ω−1 cm−1 at 300 K) than the melt-quenched samples is attributed to the higher value of disorder (entropy) in the former. 相似文献
60.