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91.
Anita Rani Surender Kumar N. R. Bannerjee 《Fresenius' Journal of Analytical Chemistry》1987,328(1-2):33-36
Summary A Potassium ion-selective electrode based on dibenzo-18-crown-6-tungstophosphoric acid precipitate membrane is prepared and conditions for the best functioning have been investigated. The working concentration and pH-range of the electrode is 2.0×10–2 to 1.3×10–6 mol/l and 2.9–6.5, respectively. The selectivity coefficient values for a large number of cations are quite low except for caesium and ammonium ions. The electrode can tolerate non-aqueous content upto 20%.
Kaliumion-sensitive Membranelektrode auf Basis von Kronenether-Heteropolysäure相似文献
92.
93.
The time-resolved fluorescence characteristics of tryptophan in flavodoxins isolated from the bacteriaDesulfovibrio gigas, Desulfovibrio vulgaris, Clostridium beijerinckii, andMegasphaera elsdenii were examined. The fluorescence decays were recorded using pulsed synchrotron radiation as the excitation source and time-correlated single-photon counting in detection. The results were analyzed as lifetime distributions using the maximum entropy method. Comparison of the fluorescence decays of normal and flavin mononucleotide-depleted flavodoxins demonstrates that radiationless energy transfer from tryptophan to flavin occurs in all flavodoxins investigated. On comparing the lifetime distribution patterns of apo and holoflavodoxins, it was noticed that a certain amount of apoprotein is present in all holoflavodoxin samples. The three-dimensional structure of two flavodoxins allowed us to compare experimental with theoretical transfer rates and the results were in fair agreement. 相似文献
94.
Hima Rani Kalita 《Tetrahedron letters》2007,48(29):5047-5049
Cuprous iodide has been found to be a very effective catalyst for allylation of aldehydes with allyltributylstannane. The catalytic system efficiently promotes the allylation reaction in DMF to produce homoallylic alcohols in high yield. 相似文献
95.
Let Гr,n—r denote the infimum of all number Г > 0 such that for any real indefinite quadratic form inn variables of type (r, n—r), determinantD ≠ 0 and real numbers c1; c2,…, cn, there exist integersx
1,x2,…,xn satisfying 0 < Q(x1+c1,x2 + c2,…,xn + cn) ≤(Г|Z > |)1/n. All the values of Гr,n—r are known except for г1,4. Earlier it was shown that 8 ≤Г1,4 ≤16. Here we improve the upper bound to get Г1,4 < 12. 相似文献
96.
The expressions for the Clark, Gazis and Wallis type of angular forces are rederived in the caseof fcc metals. These expressions are now foundtobe equivalent to the deLauney type of angular forces. 相似文献
97.
We have studied the mean free path of He fragments from projectile beams of Ar, Fe and Kr of energy 1 ? E ?2A GeV at different distances from their production point and found that they are the same, independent of their (i) energy, (ii) target size, (iii) target excitation, (iv) He multiplicities and (v) production angles. 相似文献
98.
Hard sphere diameters of liquid alkali metal alloys (Na-Cs and K-Rb) are calculated at 373 K ensuring the minimum Helmholtz
free energy of the system. These diameters are then used to fix the packing density of the alloy. On alloying, the hard sphere
diameters of Na in Na-Cs and K in K-Rb alloys expand whereas those of Cs and Rb contract. 相似文献
99.
The lattice dynamics of the b.c.c. lattice has been investigated using the central and the angular forces which are in general rotationally invariant. It has been observed that the four force constants are related to three elastic constants only. Dispersion curves for sodium were calculated and were found to be in excellent agreement with experiment. 相似文献
100.
Rani Siromoney Kamala Krithivasan Gift Siromoney 《Proceedings Mathematical Sciences》1973,78(2):72-88
Following the general linguistic approach proposed by Narasimhan to pattern recognition we proposed two generative models,viz., the matrix models and the more powerful two-dimensional array models. In this paper we generalize the matrix models ton-dimensions and establish that then-dimensional matrix models are closed under union, concatenation, Kleene closure, ∈-free homomorphism, inverse homomorphism and intersection with regular matrices. Symmetry operations such as translation, reflection and half-turn are examined. 相似文献