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71.
Let E be a compact subset of with connected, regular complement and let G(z) denote Green’s function of Ω with pole at ∞. For a sequence (pn)nΛ of polynomials with degpn=n, we investigate the value-distribution of pn in a neighbourhood U of a boundary point z0 of E if G(z) is an exact harmonic majorant of the subharmonic functions in . The result holds for partial sums of power series, best polynomial approximations, maximally convergent polynomials and can be extended to rational functions with a bounded number of poles. 相似文献
72.
Upon treatment with Fe(CO)5 in an aromatic hydrocarbon solvent aromatic acid chlorides gave an mixture of triarlmethane and tetraarylethane. The reaction may proceed via benzaldehyde and diarylmethanol intermediates. A free radical mechanism is proposed. 相似文献
73.
The 13C NMR spectra of forty-six cyclic dithioacetals and their derivatives have been studied. A set of shift parameters was established for each of these heterocycles as substituent. Based on the Hammett type correlation for substituted benzenes, the σP +values of cyclic dithioacetal groups have been determined. 相似文献
74.
The reactions of dithianes with W(CO)6 in refluxing chlorobenzene give dimeric alkenes and their reduced products; fluorenone derivative yielding trimer 8. A radical mechanism is suggested. The structure of 8 has been determined by a single-crystal X-ray diffraction study. Crystal data: P21/n; a = 11.948(5), b = 16.8795(14), c = 13.491(6) Å, β = 105.03(3)°, Z = 4, V = 2628(2) Å3; RF = 0.061, RWF = 0.051 for 2142 reflections and 353 variables. 相似文献
75.
H. H. G. Jellinek Ming Dean Luh 《Journal of polymer science. Part A, Polymer chemistry》1969,7(8):2445-2449
A novel method of metal removal and recovery and recovery is described. This method may be useful in connection with various types of water pollution. It is based on the fact that metal ions form water-soluble complexes with water-soluble polyelectrolytes, such as polyacids. These complexes can be precipitated with polybases and the metal can be recovered by treating the precipitate with mineral acid. The remaining polymer complex can be used again for further precipitation. Experiments with Cu2+ and Co2+ ions are given in some detail; general observations concerning other cases are included. 相似文献
76.
Hoong-Kun Fun Tsong-Jen Lee Tahir Tahirov Tian-Huey Lu Hung Luh Chung-Sun Chung 《中国化学会会志》1993,40(5):429-435
The nickel(II) and copper(II) complexes of meso-3,6,6,9-tetramethyl-4,8-diazaundecane-2,10-dione dioxime (meso-HM-PAO) have an intramolecular hydrogen bond between cis oxime groups. [Cu(meso-HM-PAO-H)(H2O)](NCS) crystallizes in space group P21/n with a = 7.692(1), b = 12.028(2), c=20.235(3) Å, β=93.03(1)°, Z = 4 and Dc=1.46 g/cm3. The final R value for this complex was 0.034 for 2223 observed reflections with I ≥ 2.5σ (I). The Cu(II) coordination is a distorted square pyramid. The Cu(II) ion is five-coorinated with the diazadioxime N atoms equatorial and water O atom axial. The Cu(II) is 0.12 Å from the equatorial plane towards the hydrate. The equatorial Cu-N distances span a narrow range, 1.953(3)-1.999(3) Å. The axial Cu-O distance is 2.314(3) Å. The thiocyanate group is almost linear. The intramolecular O ?O hydrogen bond length is 2.479(4) Å. [Ni(meso-HM-PAO-H)](ClO4) crystallizes in space group P21/c with a = 14.774(3), b = 12.752(3), c = 20.035(4) Å, β = 92.94(3)°, Z = 8 and Dc = 1.51 g/cm3. The final R value for the complex was 0.053 for 4794 observed reflections with F ≥ 4σ (F). The coordination about Ni(II) is a slightly distorted square plane. The Ni(II) ion is 0.0673(7) Å from the best plane of the four donor nitrogen atoms away from the perchlorate ion. The Ni-N distances span a narrow range 1.863(4)-1.927(4) Å. There are two molecules per asymmetrical unit resulting in eight molecules being packed in an unit cell; they are bound together by van der Waals interactions. The O-H ?O bonds of these complexes give characteristic infrared absorptions as well as chemical shift of the 1H NMR signal (Ni complex). 相似文献
77.
78.
W.A. Kaminski Chia-Hui Wang Luh C. Tao James H. Weber 《The Journal of chemical thermodynamics》1982,14(12):1129-1134
Values of (p, T, x, y) were determined at 101.325 kPa for each of two quinary systems containing n-hexane + ethanol + methylcyclopentane + benzene and either + toluene or + methanol. The experimental results were compared with those determined from the Wilson equation using parameters obtained from binary results. 相似文献
79.
A summary of recent advances on the chemistry and photophysics of silylene-spaced divinylarene copolymers is presented. The silicon moieties have been shown to serve as an insulating spacer in these copolymers. The photophysical studies have provided useful insights into how chromophores in polymers interact intramolecularly. Because different chromophores can be regioregularly introduced into the polymeric chain, these copolymers have been extensively used as models for studying energy transfer, light harvesting as well as chiroptical transfer. 相似文献
80.