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Abstract  

Weak atomic decompositions of B-valued martingales with two-parameters in weak Hardy spaces w p Σα and w p H α are established and the boundedness of sublinear operators on these spaces are proved. By using them, some characterizations of the smoothness of Banach spaces are obtained.

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Abstract  

Some characterizations of S-paracompact spaces are given. We introduce a class of S-expandable spaces and study topological properties of S-expandable spaces.

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Summary  

Single aerosol particles were analyzed in the ambient air of the center of Shanghai by scanning proton microprobe to obtain characteristic X-ray spectra (micro-PIXE) which were considered to be the fingerprints of these aerosol particles. The origin of the lead-containing particles was identified by the combination of the micro-PIXE spectra with pattern recognition technique. It was found that the most of the lead-containing particles were derived from vehicle exhaust, coal combustion and soil dust.

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Abstract  

In order to enrich the thermokinetic research methods and enlarge the applicable range of the thermokinetic time-parameter method, the integral and differential thermokinetic equations of consecutive first-order reaction have been deduced, and the mathematical models of the time-parameter method for consecutive first-order reactions have been proposed in this paper. The rate constants of two steps can be calculated from the same thermoanalytical curve measured in a batch conduction calorimeter simultaneously with this method. The thermokinetics of saponifications of diester in aqueoushanol solvent has been studied. The experimental results indicate that the time-parameter method for the consecutive first-order reaction is correct.

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Abstract  

In the present study, the effect of primary processing route on the dissolution and precipitation reactions in a commercial Al−Si alloy (designated as A390) is investigated using differential scanning calorimetry (DSC). The Al−Si alloy selected for the present investigation was processed using conventional casting and spray atomization and deposition routes. The results of differential scanning calorimetry conducted on the as-processed samples indicated no significant dissolution reaction for the as-cast A390 alloy when compared to the similar results obtained for as-spray atomized and deposited samples. However, the thermal analysis conducted on the solutionized cast and spray deposited samples exhibited no significant difference in the kinetics of precipitation reactions. The results of the differential thermal analyses were finally rationalized in terms of observed microstructural features.

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Abstract  

Effects of gaseous hydrogenation on crystallization behavior of melt-spun Mg63Pr15Ni22 amorphous ribbons have been investigated. The crystallization peak temperature T p1 shifted to higher temperature with increasing heating rate for the un-hydrogenated Mg63Ni22Pr15 metallic glass, however, it is nearly unchanged for the hydrogenated sample. The present work indicates that the crystallization is a nucleation-and-growth process for the un-hydrogenated Mg63Ni22Pr15 metallic glass. However, the crystallization of hydrogenated sample begins with nucleation and then diffusion-controlled growth takes place.

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Abstract  

The variations of size, intensity, and size distribution of free volumes generated in the network of molecular chains of gelatin at the sol-gel transition were studied by means of the positron annihilation lifetime technique. Although variation in average free-volume radius was not recognized, a variation of free-volume content was observed at the sol-gel transition point of gelatin with an addition of saccharose.

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Abstact  

The reduction process of silica supported cobalt catalyst was studied by thermal analysis technique. The reduction of the catalyst proceeds in two steps:

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$Co_3 O_4 + H_2 \to 3CoO + H_2 O, 3CoO + 3H_2 \to 3Co + 3H_2 O$$ \end{document}
which was validated by the TPR and in-situ XRD experiments. The kinetic parameters of the reduction process were obtained with a comparative method. For the first step, the activation energy, E a, and the pre-exponential factor, A, were found to be 104.35 kJ mol−1 and 1.18�106∼2.45�109 s−1 respectively. The kinetic model was random nucleation and growth and the most probable mechanism function was found to be f(α)=3/2(1−α)[−ln(1−α)]1/3 or in the integral form: g(α)=[−ln(1−α)]2/3. For the second step, the activation energy, E a, and the pre-exponential factor, A, were found to be 118.20 kJ mol−1 and 1.75�107∼2.45 � 109s−1 respectively. The kinetic model was a second order reaction and the probable mechanism function was f(α)=(1−α)2 or in the integral form: g(α)=[1−α]−1−1.

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Abstract  

Differences of size, content and size distribution of free volumes in linear branched and three-armed polystyrenes, synthesized by radical and anionic processes, were observed by positron annihilation lifetime measurements. The temperature dependence of an average free volume radius was quite similar among polystyrenes of different architectures and molecular weight distributions. The free volume radius increased with temperature, from 0.27 nm (T:60 K) to 0.29 nm (T:260 K) and 0.30 nm (T g:363 K), then to 0.35 nm (423 K), showing turning at and transition temperature. The free volume content decreased from 60 K to 220 K to 300 K showing peculiar minimum at 220 K to 300 K depending on the molecular shape, increased above 320 K, upto 340 to 360 K. The free volume contents decreased with an increase of molecular weight and by an addition of oligomer or plasticiser, suggesting differences in relaxation time or molecular motion between the edge and middle portions of molecular chain and filling effect of smaller molecules in free volumes, respectively. The apparent free volume fraction showed clear variations atT andT g. Size distribution of free volumes suggested more complicated behavior of free volume upon the molecular relaxations and filling effect.

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Abstract

The phenomenon of all-elements-sleeping-beauties in science is revealed by four special cases. The ‘sleeping beauties’ prick their fingers on the ‘spindles’ so that they fall into sleep then are awakened by their ‘princes’. The authors speculate that the phenomenon could happen in scientific literatures with high quality.

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