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61.
The kinetics of C6H5 reactions with n‐CnH2n+2 (n = 3, 4, 6, 8) have been studied by the pulsed laser photolysis/mass spectrometric method using C6H5COCH3 as the phenyl precursor at temperatures between 494 and 1051 K. The rate constants were determined by kinetic modeling of the absolute yields of C6H6 at each temperature. Another major product C6H5CH3 formed by the recombination of C6H5 and CH3 could also be quantitatively modeled using the known rate constant for the reaction. A weighted least‐squares analysis of the four sets of data gave k (C3H8) = (1.96 ± 0.15) × 1011 exp[?(1938 ± 56)/T], and k (n‐C4H10) = (2.65 ± 0.23) × 1011 exp[?(1950 ± 55)/T] k (n‐C6H14) = (4.56 ± 0.21) × 1011 exp[?(1735 ± 55)/T], and k (n?C8H18) = (4.31 ± 0.39) × 1011 exp[?(1415 ± 65)T] cm3 mol?1 s?1 for the temperature range studied. For the butane and hexane reactions, we have also applied the CRDS technique to extend our temperature range down to 297 K; the results obtained by the decay of C6H5 with CRDS agree fully with those determined by absolute product yield measurements with PLP/MS. Weighted least‐squares analyses of these two sets of data gave rise to k (n?C4H10) = (2.70 ± 0.15) × 1011 exp[?(1880 ± 127)/T] and k (n?C6H14) = (4.81 ± 0.30) × 1011 exp[?(1780 ± 133)/T] cm3 mol?1 s?1 for the temperature range 297‐‐1046 K. From the absolute rate constants for the two larger molecular reactions (C6H5 + n‐C6H14 and n‐C8H18), we derived the rate constant for H‐abstraction from a secondary C? H bond, ks?CH = (4.19 ± 0.24) × 1010 exp[?(1770 ± 48)/T] cm3 mol?1 s?1. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 49–56, 2004 相似文献
62.
63.
C.M.Lin C.T. Chia Y.J. Shu Y.K. Tseng 《光散射学报》2005,17(3):216-218
Weperformedthehigh-pressureRaman measurementofthethreenanosizedZnOcrystals. Wefoundthesmallerthesize,thehigherthe pressuretoinducethephasetransitionfrom w櫣rzitetorock-saltstructure. High-pressureRamanmeasurementsof nona-shapedZnOcrystalswerepreformed.The… 相似文献
64.
Kuan‐Wei Lee Hong‐Cheu Lin 《Journal of polymer science. Part A, Polymer chemistry》2007,45(20):4564-4572
A series of new liquid crystalline homopolymers, copolymers, and block copolymers were polymerized from styrene‐macroinitiator ( SMi ) and methacrylates with pendent 4,4′‐bis(biphenyl)fluorene ( M1 ) and biphenyl‐4‐ylfluorene ( M2 ) groups through atom transfer radical polymerization (ATRP). The number‐average molecular weights (Mn) of polymers P1 ‐ P4 were 10,007, 14,852, 6,275, and 10,463 g mol?1 with polydispersity indices values of 1.21, 1.15, 1.31, and 1.22, respectively. All polymers exhibit the nematic phase. The thermal, mesogenic, and photoluminescent properties of all polymers were investigated. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4564–4572, 2007 相似文献
65.
The present study is concerned with the determination of the optimal shape for a package containing multiple heating elements.
The optimization tool has been developed based on the inverse heat transfer (IHT) approach, incorporating a direct problem
solver, a numerical grid generator, a direct-differentiation sensitivity analyzer, and the conjugate gradient method. Shape
design that leads to a specified outer surface temperature distribution is predicted by the approach. In this study, the effects
of internal heat generation on optimal shapes of the packagings have also been evaluated. Several practical cases with various
imbedded heating elements and thermal conditions are studied. Results show that the approach provides an efficient computer-aided
design scheme for the shape profile determination. 相似文献
66.
Junsaku Nitta Yiping Lin Takaaki Koga Tatsushi Akazaki 《Physica E: Low-dimensional Systems and Nanostructures》2004,20(3-4):429
We report on electron g-factor in an InAs-inserted In0.53Ga0.47As/In0.52Al0.48As heterostructure. The gate voltage dependence of g-factor is obtained from the coincidence method. The obtained g-factor values are surprisingly smaller than the g-factor value of bulk InAs, and it is close to the bare g-factor value of In0.53Ga0.47As. The large change in g-factor is observed by applying the gate voltage. The obtained gate voltage dependence is not simply explained by the energy dependence of g-factor. 相似文献
67.
By using microlocal analysis, the propagation of weak singularities in Cauchy problems for quasilinear thermoelastic systems in three space variables are investigated. First, paradifferential operators are employed to decouple the quasilinear thermoelastic systems. Second, by investigating the decoupled hyperbolic-parabolic systems and using the classical bootstrap argument, the property of finite propagation speeds of singularities in Cauchy problems for the quasilinear thermoelastic systems is obtained. Finally, it is shown that the microlocal weak singularities for Cauchy problems of the thermoelastic systems are propagated along the null bicharacteristics of the hyperbolic operators. 相似文献
68.
Shy-Der Lin 《Journal of Mathematical Analysis and Applications》2004,294(2):399-411
The main object of this paper is to investigate several general families of hypergeometric polynomials and their associated single-, double-, and triple-integral representations. Some known or new consequences of the general results presented here, involving such classical orthogonal polynomials as the Jacobi, Laguerre, Hermite, and Bessel polynomials, and various other relatively less familiar hypergeometric polynomials, are also considered. Each of the integral representations, which are derived in this paper, may be viewed also as a linearization relationship for the product of two different members of the associated family of hypergeometric polynomials. 相似文献
69.
本文介绍概率抽样法在钢球生产过程中的应用,通过此法确定钢球生产中各工序质量监测的最佳抽检方案,以确保产品被接受的概率最大。 相似文献
70.