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991.
Numerical simulations have been performed for a 2D supersonic mixing layer with two different types of excitation, namely
the introduction of a T-S wave at the inlet and the enforcement of the inflow speed on the low speed side to have periodic
stream-wise undulations. The results showed that both ways were effective when the convective Mach numberMc was less than 1, but the latter was more effective than the former. Systematic computations have also been done to analyze
the effect of different parameters on mixing. 相似文献
992.
Viviane S. M. Campos Chang C. Y. Dorea 《Annals of the Institute of Statistical Mathematics》2005,57(3):443-453
Let {X
n
}
n
≥0 be a Markov chain with stationary distributionf(x)ν(dx), ν being a σ-finite measure onE⊂R
d
. Under strict stationarity and mixing conditions we obtain the consistency and asymptotic normality for a general class of
kernel estimates off(·). When the assumption of stationarity is dropped these results are extended to geometrically ergodic chains.
Partially supported by CAPES.
Partially supported by CNPq, PROCAD/CAPES, PRONEX/FAPDF and FINATEC/UnB. 相似文献
993.
I. Fortelný D. Hlavat J. Mikeov D. Michlkov L. Potrokov I. loufov 《Journal of Polymer Science.Polymer Physics》2003,41(6):609-622
The effect of mixing conditions on the morphology, molten‐state viscoelastic properties, and tensile impact strength of polystyrene/polyethylene (80/20) blends compatibilized with styrene–butadiene block copolymers containing various numbers and lengths of blocks was studied. Under all mixing conditions, an admixture of a styrene–butadiene block copolymer led to a finer phase structure and to an increase in the dynamic viscosity, storage modulus, and tensile impact strength. The effects were stronger for S–B diblock with a short styrene block than for S–B–S–B–S pentablock with long styrene blocks (where S represents styrene and B represents butadiene). For all blends mixed longer than 2 min, the mixing time had only a small effect on their morphology and properties. Surprisingly, the localization of S–B diblock copolymers was strongly dependent on the rate of mixing. The mixing rate had a nonnegligible effect on the viscoelastic properties of the compatibilized blends. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 609–622, 2003 相似文献
994.
995.
Y. Murakami H. Kido A. Kenjo T. Sadoh T. Yoshitake M. Miyao 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):505
Effects of Ar+ ion-beam irradiation on solid-phase growth of β-FeSi2 have been investigated. Fe (10 nm)/Si structures were irradiated with 25 keV Ar+ (5.0×1015 cm−2) at a temperature of 25°C (sample A) or 400°C (sample B), and subsequently annealed at 800°C. A reference was obtained after annealing without irradiation (sample C). X-ray diffraction results indicated that β-FeSi2 was formed after annealing at 800°C for 5 h, and the formation rate was the fastest for sample A and the slowest for sample C, i.e., A>BC. However, Auger electron spectroscopy measurements showed that atomic mixing at Fe/Si interface before annealing was B>AC. These results suggested that amorphization of Si substrate, in addition to atomic mixing, enhanced the solid-phase growth of β-FeSi2, which was confirmed experimentally. Moreover, a direct band gap of 0.89 eV was observed for the sample with pre-amorphization by the Fourier-transform infrared (FT-IR) spectroscopy measurements. These enhancement effects were attributed to that the phase transition to β-FeSi2 was accelerated by atomic arrangement induced during annihilation of excess vacancies. These enhancement effects can be utilized for nano-fabrication of β-FeSi2 by using focused ion-beam irradiation. 相似文献
996.
Tomás Pérez-Ruiz Carmen Martínez-Lozano Virginia Tomás José Fenoll 《Mikrochimica acta》2003,141(1-2):73-78
The chemiluminescence reaction of lucigenin with glucose and fructose in the presence of Brij-35 and in alkaline solution
was used to develop kinetic methods for the determination of both hexoses individually and mixed together. A stopped-flow
mixing module coupled to a photomultiplier tube allowed kinetic and equilibrium measurements, which were used for the individual
determination of glucose and fructose. The same measurements were used to analyse the mixture of both sugars using a two equation
system, which was resolved by multiple linear regression. The ranges of the calibration graphs obtained by using kinetic and
equilibrium measurements were 25–1000 μg ml−1 and 75–1100 μg ml−1, respectively, for glucose and 1–350 μg ml−1 and 5–250 μg ml−1, respectively, for fructose. Mixtures of glucose and fructose in ratios between 1:0.4 and 40:1 were satisfactorily resolved.
Received February 27, 2002; accepted August 6, 2002 相似文献
997.
998.
Kangming Nie Sixun Zheng Fei Lu Qingren Zhu 《Journal of Polymer Science.Polymer Physics》2005,43(18):2594-2603
Inorganic–organic hybrids mediated by hydrogen‐bonding interactions involving silicon oxide network and poly(ε‐caprolactone) (PCL) were prepared via an in situ sol–gel process of tetraethoxysilane in the presence of PCL. Fourier transform infrared spectroscopy indicated that there were hydrogen‐bonding interactions between carbonyls of PCL and silanol hydroxyls that were formed by incomplete polycondensation in the sol–gel process. In terms of the frequency shift of the hydroxyl stretching vibration bands, it is concluded that the strength of the interassociation between PCL and silicon oxide networks is weaker than that of the self‐association in the control silica network. The phenomenon of equilibrium melting point depression was observed for the PCL/silica system. The hybridization of PCL with silica network causes a considerable increase in the overall crystallization rate and dramatically influences the mechanism of nucleation and growth of the PCL crystallization. The analysis of isothermal crystallization kinetic data according to the Hoffman‐Lauritzen theory shows that with increasing silica content in the hybrids, the surface energy of extremity surfaces increases dramatically for the hybrids. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2594–2603, 2005 相似文献
999.
§ 1 Introduction and main resultsL et { X,Xn;n≥ 1} be a sequence of random variables with common distributionfunction F,mean0 and positive,finite variance,and set Sn= nk=1 Xk,n≥ 1.Also letlogx= ln(x∨e) ,log logx=log(logx) and(x) =2 xlog logx.Gut and Sp taru[2 ] studied theprecise asymptotics on the law of the iterated logarithm.One of their results is as follows.Theorem A.Spuuose that{ X ,Xn;n≥ 1} is a sequence of i.i.d.random variables with EX= 0 and0 相似文献
1000.
《中国颗粒学报》2005,(2)
The processing of fine-grained particles with diameters between 1 and 10 microns is difficult due to strong van-der-Waals attraction forces. In order to improve the handling properties, the fine-grained particles, i.e. host-particles,are coated with various nanoparticles, i.e. guest-particles. The mixing of fine-grained powders is influenced by particle-particle interactions. If these forces are distinctively used, both interactive and ordered mixtures can be produced.These particle mixtures consist of composite-particles that have new physical properties. These modified properties d epend strongly on the coating process, the diameter- and mass-relationship of the guest- and the host-particles. The properties of the composite-particles can systematically be adjusted to the requirements of industrial applications. For example, a laboratory bubbling fluidized bed can be used to describe the conveying behavior of the functionalized host-particles. Applications for the functionalized particles are in the pharmaceutical and the powder coating industries,e.g. enhanced dry powder inhalers and thin lacquer films. The present research compares three different mixing/coating processes. The composite-particles are characterized by TEM, SEM and with their fluidization characteristics. The coating process itself is monitored by the electrostatic charge of the particles. 相似文献