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191.
Complexation in the Co(II)–H6X–H2O, Ni(II)–H6X–H2O, and Co(II)–Ni(II)–H6X–H2O systems (H6X is nitrilotrimethylenephosphonic acid) was studied by spectrophotometry. The formation of binuclear complexonates Ni2H2X · 7H2O, Co2H2X · 5H2O, and NiCoH2X · 6H2O was demonstrated. These compounds were isolated from the solution, their composition was determined, the thermal stability was studied, and the kinetic parameters of dehydration were calculated.  相似文献   
192.
Light scattering in cholesteric liquid crystals with a large pitch   总被引:3,自引:0,他引:3  
Optical properties of cholesteric liquid crystals with a pitch larger than the wavelength of light are considered. Normal waves of the medium and the Green function of the electromagnetic field are analyzed. A general algorithm based on the application of the Kirchhoff method is proposed for calculating the scattered light intensity in media with a one-dimensional periodic structure. The WKB vector method is used for calculating the spatial correlation function of thermal fluctuations of the director. It is found that the transformation of two fluctuation modes takes place is some regions. The angular and polarization dependences of the intensity of light scattered from fluctuations of the director are calculated. It is found, in particular, that the intensity of scattering is a nonmonotonic function of the size of the system.  相似文献   
193.
194.
A highly efficient and expeditious one-pot approach towards 2-(3-oxoindolin-2-yl)acetonitriles was designed, which involves a base-assisted aldol reaction of ortho-nitroacetophenones, followed by hydrocyanation, triggering an unusual reductive cyclization reaction.  相似文献   
195.
Aminomethylation of xanthane hydride (5-amino-1,2,4-dithiazole-3-thione) with the RNH2–HCHO system has resulted in the formation of the derivatives of new heterocyclic system (3,7-dihydro-5H-[1,2,4]-dithiazolo[4,3-a][1,3,5]triazine) in low yields. The reaction of xanthane hydride with dicyandiamide has led to thioammeline [4,6-diamino-1,3,5-triazine-2(5Н)-thione]. Some practically important properties of xanthane hydride and its derivatives have been investigated. Xanthane hydride has efficiently exhibited carbon steel corrosion in neutral aqueous media. The prepared compounds have not exhibited growth-regulating or antidote activity to herbicide 2,4-D.  相似文献   
196.
The possibility of using solid-state and liquid PVC-membrane electrodes based on ionic liquids to design a potentiometric multisensor system is assessed. Ionic liquids with 1,3-dihexadecylimidazolium cation and chloride, bromide, iodide, and nitrate anions are used. The sensitivity parameters of the sensors are determined. A multisensor array is applied to detect chloride and iodide anions in the multicomponent mixture. The designed system is used to discriminate between mineral waters of different compositions by applying the method of principal component analysis (PCA).  相似文献   
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198.
The propagation and scattering of light in stratified media are considered. Based on the Maxwell equations, the present approaches to the solution of these problems are formulated in a unified way. The particular features of the wave propagation in stratified media are discussed. Scalar and vector fields are considered. Media with small-and large-scale regular inhomogeneities are examined. The construction of the Green’s function of the wave equation in a spatially homogeneous medium is discussed. Stratified isotropic and anisotropic media are analyzed. The scattering of light in a stratified medium is studied with emphasis on the Kirchhoff method, as this makes it possible to obtain calculation formulas in a form convenient for comparing the theory with the experiment. The propagation of waves in photonic crystals and the formation of forbidden zones in such objects are briefly considered.  相似文献   
199.
Methods have been developed for the synthesis of 1,3-diazapyrenes, 8(6)-aryl-6(8)-oxo-1,6,7,8-tetra-hydro-1,3-diazapyrenes, and 1,3,7-triazapyrenes based on a three-component reaction of perimidines with 1,3,5-triazines and carbonyl compounds, benzonitrile, or vinyl butyl ether in polyphosphoric acid.  相似文献   
200.
Optics and Spectroscopy - Electrically controlled light refraction in a nematic liquid crystal (LC) with homeoplanar orientation possessing different thicknesses has been investigated at angles of...  相似文献   
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