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In the present communication a method based on the three body forces for the evaluation of second and third order elastic constants of mixed ammonium halides has been described. The Lundqvist three body potential is used along with long range Coulombian and short-range overlap repulsive potentials. The latter is taken of the Born-Mayer type and effective up to first neighbours only. It has been assumed that the charge transfer and short-range parameters depend linearly on the composition of solid solutions. Theoretical results obtained, for the entire range of compositions of mixed NH4Cl and NH4Br, have been compared with the recently measured experimental values and the theoretical results of other workers, whenever these are available.The authors are thankful to Dr. J. Shanker, Department of Physics, Agra University, Agra, for helpful discussions. 相似文献
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Jaspal Singh Aujla 《Linear algebra and its applications》1999,290(1-3):109-118
There is one to one correspondence between positive operator monotone functions on (0, ∞) and operator connections. For a symmetric connection σ, it is proved that the map X → (AσX)σ(BσX) from positive operators on a Hilbert space to itself, has a unique fixed point. Here σ denotes the dual of σ. It is also proved that |||AσB||| |||A|||σ|||B||| for all unitarily invariant norms ||| · ||| and for all positive operators A,B. 相似文献
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A general, efficient, and inexpensive method for the N-arylation of indoles using a catalytic system derived from CuI and benzotriazole is reported. Selective mono N-arylation of indoles with ortho-dihaloarenes has also been successfully achieved in good yields using this protocol. 相似文献
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We report an exceptionally mild, general and efficient copper catalyzed cross coupling reaction of aryl bromides and thiols using 0.5 mol % CuI and 1 mol % benzotriazole. Experimental simplicity, generality, functional group tolerance and low cost of the catalyst are advantages of the protocol. 相似文献
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Achiral four-ring unsymmetrically substituted toluene-derived liquid crystals have been designed and synthesised by known and straightforward methods. All these compounds exhibit nematic phase over wide temperatures. 相似文献
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G. K. Solanki Sudeep Goyal S. K. Arora Dipika B. Patel M. K. Agarwal 《Indian Journal of Physics》2009,83(3):275-284
In this paper, we have attempted to fabricate PEC solar cells with mixed crystals of Zirconium sulphoselenide. Energy band
location and redox analysis of the material have been made using Mott-Schottky plots. These studies justify the selection
of an appropriate electrolyte for PEC work. Various solar cells fabricated with single crystals of selenium rich and selenium
deficient zirconium sulphoselenide have been prepared. The solar cell parameters e.g. the fill factor (FF), open circuit voltage (Voc), short circuit current (Isc) and efficiency (η) for all the different cells have been determined. In order to see the effect of enhancement of selenium
in ZrSxSe2−x on photoresponse, the electrolyte and intensity of illumination were kept constant and all the electrodes were prepared from
crystals showing absolutely plane faces obtained through the act of cleavage with the help of an adhesive tape. The results
have been thoroughly analysed and the implications have been discussed. 相似文献
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This paper reports the growth of germanium monosulphide (GeS) single crystals by vapour phase technique using different transporting
agents. The single crystallinity and composition of the grown crystals have been verified by transmission electron microscopy
(TEM) and energy dispersive analysis of X-rays (EDAX) respectively. Resistivity measurements have been carried out in different
temperature ranges. Transport parameters, e.g. resistivity, Hall coefficient, carrier concentration and mobility have been
measured at varying magnetic fields. All the experimental results have been explained. 相似文献