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161.
A simple, accurate and reliable titrimetric method is described for the determination of thiophanate-methyl, an important commercial fungicide. The method is based on its direct titration at room temperature with ammonium hexanitratocerate(IV) in sulphuric acid medium in the presence of potassium iodate as catalyst. The method permits detection of the end-point visually, potentiometrically or spectrophotometrically. The proposed method is recommended for routine determination of the fungicide in its commercial formulations. 相似文献
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Sukhjinder Singh Madanmohan Singh Gill Rajendar D. Verma 《Journal of fluorine chemistry》1985,27(2):133-142
V(SO3CF3)3, VO(SO3CF3)2 and VO(SO3CF3)3 have been prepared by reacting V(O2CCF3)3, VO(O2CCF3)2 and VOC13 with HSO3CF3. The i.r. data suggest a bridging bidentate nature for SO3CF3 groups. The diffuse reflectance spectrum of V(SO3CF3)3 suggests hexacoordination of vanadium, whilst that of VO(SO3CF3)2 is comparable to either five or six coordinated oxovanadium (IV) systems. The magnetic moments of V(SO3CF3)3 and VO(SO3CF3)2 are slightly lower than the spin-only values. Thermal decomposition of these triflates is simple. All the three triflates form coordination complexes with pyridine, 2, 2′-bipyridyl and triphenylphosphine oxide. 相似文献
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The purpose of this paper is to develop a variational technique, using the variational principle of non-equilibrium thermodynamics for the solution of laminar stagnation point flow and heat transfer in two dimensions. The governing principle of dissipative processes is formulated for the problem and then using the boundary conditions of the system the elementary trial functions of third degree are assumed for the flow and temperature fields in the vicinity of the wall. The viscous and thermal boundary layer thicknesses, the skin friction and the rate of heat transfer from the wall to the fluid are obtained. It is found that these new approximate results are quite close to the exact known ones. These results are better than those of the Kármán-Pohlhausen technique.The authors are thankful to the referee for his valuable suggestions. 相似文献
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The thermal conductivity, κ, of NbSe3 has been measured by novel self-heating techniques that allowed the electric field dependence of κ to also be measured. Measurements were made from 35 K to room temperature. Above the charge density wave transitions, the phonon thermal conductivity is 4–7 times the electron thermal conductivity, and it rises smoothly below the transitions, indicating that phonon-phonon scattering predominates. Phonon mean free parths have been estimated at 187 A° at 60 K and 60 A° at 150 K. No clear anomalies were observed at the phase transitions, giving upper limits to changes in the phonon mean free path. No field dependence of κ was observed. 相似文献