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991.
992.
993.
扩散限制聚集与粘性指化图案的模拟研究顾健德,田安民,鄢国森(四川大学化学系,成都,610064)关键词DLA,粘性指化,计算机模拟大自然经常以非常奇妙的方式向人们展示其魅力,吸引人们不断去思考和探索.四川大学图书馆文献阅览室的玻璃顶棚上出现的粘性指化... 相似文献
994.
1,2,2-Trimethyldisilane-1,1,2-triol (1) is formed as an unstable intermediate upon hydrolysis of oligo(trimethyldisilanylsesquiazane). In the absence of trapping
agents it undergoes rapid condensation to give ether-soluble poly(trimethyldisilanyloxane) which contains silanol groups.
Treatment of the hydrolysis products with chlorotrimethylsilane in the presence of triethylamine affords trimethylsiloxy derivatives,
(Me3SiO)2MeSiSiMe2(OSiMe3),5,6, and [Si2Me3O
x
(OSiMe3)
y
]
n
. The isolation of these products indicates that disilanetriol1 readily undergoes condensation to form hydroxylcontaining six-membered rings and polysiloxanes. The condensation of compound1 in the presence of Me3SiOH has been studied. The ratio between the isomeric cyclosiloxanes5 and6 has been determined both by1H NMR spectroscopy and by a chemical method (chlorinolysis).
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1788–1792, October, 1993. 相似文献
995.
996.
ZHANG Yifeng GUO Hong ZHANG Guangming YAN Xiuyun YIN Shougen ZHANG Zhengpu Institute of Taitai Pharmaceutical Co. Ltd Shengzhen China State Key Lab. of Functional Polymeric Materials for Adsorption Separation Institute of Polyme 《Chinese Journal of Reactive Polymers》2002,(1)
1. INTRODUCTION Fig.1 The Chemical Structure of Milupeinan As a new type of antibiotics Milupeinan, not only possesses antibacterial activities against a wide range of Gram-positive and Gram-negative bacteria, but also higgh stability under th… 相似文献
997.
H. Fiedler 《Numerische Mathematik》1987,51(5):571-581
Summary Interpolatory quadrature formulae consist in replacing
by
wherep
f
denotes the interpolating polynomial off with respect to a certain knot setX. The remainder
may in many cases be written as
wherem=n resp. (n+1) forn even and odd, respectively. We determine the asymptotic behaviour of the Peano kernelP
X
(t) forn for the quadrature formulae of Filippi, Polya and Clenshaw-Curtis. 相似文献
998.
The percolation transition of geometric clusters in the three-dimensional, simple cubic, nearest neighbor Ising lattice gas model is investigated in the temperature and concentration region inside the coexistence curve. We consider quenching experiments, where the system starts from an initially completely random configuration (corresponding to equilibrium at infinite temperature), letting the system evolve at the considered temperature according to the Kawasaki spinexchange dynamics. Analyzing the distributionn
l(t) of clusters of sizel at timet, we find that after a time of the order of about 100 Monte Carlo steps per site a percolation transition occurs at a concentration distinctly lower than the percolation concentration of the initial random state. This dynamic percolation transition is analyzed with finite-size scaling methods. While at zero temperature, where the system settles down at a frozen-in cluster distribution and further phase separation stops, the critical exponents associated with this percolation transition are consistent with the universality class of random percolation, the critical behavior of the transient time-dependent percolation occurring at nonzero temperature possibly belongs to a different, new universality class. 相似文献
999.
Composite membranes were prepared by (a) infiltrating NAFION with SiO2-P2O5-ZrO2 sol, and (b) recasting a film using NAFION solution containing SiO2-P2O5-ZrO2 sol. The membranes were characterized by Differential Thermal Analysis and ac-impedance spectroscopy as a function of relative humidity. The influences of the heat treatment (80°C–150°C) and cleaning on the electrical properties were investigated. The incorporation of SiO2-P2O5-ZrO2 gels into NAFION lead to improvements in its thermal stability and proton conductivity. 相似文献
1000.