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31.
32.
Novel termetallic isopropoxides are reported which may be represented by the general formulae: [(PriO)3M(μ-OPri)2Be(μ-OPri)2Al(OPri)2], [(PriO)2M(μ-OPri)2Be(μ-OPri)2Al(OPri)2]2 [where M = Ti(IV), Zr(IV) and Hf(IV)] and [(PriO)4M(μ-OPri)2Be(μ-OPri)2Al(OPri)2] [where M = Nb(V) and Ta(V)]. Attempts to synthesize derivatives with the general formula, [(PriO)7M2(μ-OPri)2Be(μ-OPri)2Al(OPri)2] [where M = Ti(IV), Zr(IV) or Hf(IV)], were unsuccessful and in all such cases a mixture of M(OPri)4 and [(PriO)3M(μ-OPri)2Be(μ-OPri)2Al(OPri)2] was obtained. All these derivatives are soluble in common organic solvents and with the exception of titanium(IV) derivatives, they can be volatilised without noticeable disproportionation. These products have been characterized by elemental analyses, molecular weights, IR, 1H NMR and (in representative cases) mass spectral studies also. 相似文献
33.
The ultrasonic velocity and density measurements of lanthanum and cerium soaps in a mixture of 60 % benzene and 40 % methanol (v/v) were used to evaluate various acoustic and thermodynamic parameters and to determine the CMC. The results were interpreted in terms of soap-solvent interaction. 相似文献
34.
O,O-Alkylenedithiophosphates of diorganotin(IV) of the type R2Sn[SP(S)O2G]2 (R = Me, Et, n-Bu, Ph; G = CH2CMe2CH2, CMe2CMe2, CMe2CH2CHMe) have been synthesized by the reactions of diorganotin(IV) dichlorides with ammonium O,O-alkylenedithiophosphates or that of diorganotin(IV) oxides with O,O-alkylenedithiophosphoric acids in 1:2 molar ratio in benzene. These new complexes are white solids which are soluble in common organic solvents and are monomeric in refluxing benzene; and they have been characterized by elemental analysis and by different spectroscopic (IR, 1H, 13C, 31P and 119Sn NMR) studies, on the basis of which a six coordinated octahedral structure has been suggested in solution. 相似文献
35.
We have calculated the velocities of the first and second sound and the structure factor for a system of interacting bosons. The two-body interatomic potential used is assumed to be composed of a hard core followed by a sum of both repulsive and attractive gaussians. 相似文献
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Summary A number of alcoholate complexes of chromium chloride with the general formula, CrCl3 · xROII (R = Me, Et, i-Pr, n-Bu and n-Ilexyl; x = 3 and 4) have been synthesized by the reactions of CrCl3 · 3 TIIF with an excess of the appropriate alcohols under reflux. Physicochemical studies such as i.r., visible reflectance, electron spin resonance spectra and thermogravimetric measurements, in addition to elemental analyses, throw light on the structure of these complexes. 相似文献
39.
We study the problem of finding a point in the relative interior of the optimal face of a linear program. We prove that in the worst case such a point can be obtained in O(n
3
L) arithmetic operations. This complexity is the same as the complexity for solving a linear program. We also show how to find such a point in practice. We report and discuss computational results obtained for the linear programming problems in the NETLIB test set.Research supported in part by NSF Grant CCR-8810107, CCR-9019469 and a grant from GTE Laboratories.Research supported in part by NSF Grant DDM-8922636 and NSF Coop. Agr. No. CCR-8809615 through Rice University. 相似文献
40.
The cell model for diffusion transition has been applied to study first order phase transition and its pressure dependence in polyethylene. The experimental data of Matsuoka have been utilized. The agreement with experimental curves gets progressively better at higher pressure values because of the accompanied crystallisation. 相似文献