Synthesis and optical properties of nanohybrids in the system constituted by silica and lanthanide phosphoramide complexes

Sol-gel process of hydrolytic polycondensation of tetramethoxysilane with trimethoxysilyl derivatives of lanthanide phosphoramide complexes was studied in order to obtain photoluminescent organic-inorganic hybrid materials. Original Russian Text N.N. Khimich, Yu.L. Zub, L.A. Koptelova, T.S. Mashchenko, E.P. Troshina, M.G. Voronkov, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 11, pp. 1789–1794.     

Parametric amplification of light in a BBO crystal with pumping by YAG:Nd laser radiation

Special features of the parameteric amplification of light in a BBO crystal in the pumping field of YAG:Nd laser radiation (λ=1.064 μm) were investigated in the case in which the wavelength of the amplified signal of light lay within the eye-safe region of the spectrum and the idle wavelength lay within the region of strong absorption. The correlation between the parametric gain coefficient and the linear absorption coefficient of the crystal has been revealed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 263–266, March–April, 2000.     

A sulfated glycoside from the preparation “tribestan”

The chemical composition and structures of the steroid glycosides forming the active principle of the preparation “tribestan,” which is used for treating impotence and female infertility, have been studied. It has been shown that together with trillin, prosapogenin A of dioscin, trillarin, dioscin, gracillin, protodioscin, and protogracillin, tribestan contains a diosgenin rhamnoglucoside sulfated in position 4 of the glucose residue, the structure of which has been shown by chemical and physicochemical methods. Institute of Ecological Genetics, Academy of Sciences of the Moldavian SSR, Kishinev. Center for Biogenic Stimulators, Sofia, Bulgaria. N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 649–652, September–October, 1990.     

Mechanism of the rf sputtering of mixed oxides

New experimental data on the growth mechanisms of multicomponent Pb(Zr,Ti)O₃, (Ba,Sr)TiO₃, and Y-Ba-Cu-O films in an rf discharge plasma are presented. An investigation of the spatial distribution of the radiated intensity of the sputtered particles in the rf plasma during the deposition of films of these mixed oxides in the epitaxial state reveals general laws governing their transport from the target to the substrate, which are stipulated by features of the negative glow of the rf discharge. The roles of external and internal parameters are examined from the standpoint of describing the mechanisms of the heteroepitaxial growth of mixed oxides. Zh. Tekh. Fiz. 68, 99–103 (September 1998)     

Chemical and Electrochemical Synthesis,Structure, and Properties of Metal Chelates of Tridentate N,S-Containing Azomethinazo Ligands

Novel Cu(II), Co(II), Ni(II), and Zn(II) complexes of 5-methyl-2-phenyl-4-[(4-phenylazo)anilinemethylylidene]- 2,4-dihydro-3H-pyrazole-3-thione and 5-methyl-4-[4-methyl-2-(4-methylphenylazo)anilinemethylylidene]- 2-phenyl-2,4-dihydro-3H-pyrazole-3-thione, i.e. ligands containing the phenylazo group in the ortho and para positions of the aniline fragment, were synthesized by the chemical and electrochemical methods. The complexes and ligands were characterized by IR, ¹H NMR, X-ray absorption spectroscopy and magnetochemistry. The azo group of the ligands is not involved in coordination to the metal.     

Gelation in solutions of high-molecular-mass polyacrylonitrile under shear deformation

The effect of shear fields on the rate of physical gelation in semidilute solutions of ultra-high-molecular-weight polyacrylonitrile in propylene carbonate and on the structural features of the resulting gels has been studied. At 30–70°C in the uniform shear field, the induction period of gelation decreases from several hours to several seconds with an increase in the shear stress. The patterns of these dependences are rather close at shear stresses above 20 Pa, while significant differences are observed at these temperatures only at low shear stresses (below 15 Pa). Depending on the shear stress, two types of gelation can be distinguished at 70°C. At stresses below 15 Pa, the polymer phase emerging in the course of shear deformation is aligned along shear lines and the sample is macroscopically nonuniform. At higher shear stresses, the structure of the sample is uniform throughout its bulk.