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  • Author or Editor: J. Li x
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Abstract  

We investigate the generalized topology generated by a subbase for a topology, and consider its applications in the theory of rough sets.

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Abstract  

It is shown that every separable k'-space with a point-countable k-system has a countable k-system, which gives an affirmative answer to Y. Tanaka's Question posed in 1982.

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Abstract  

We obtain two countable properties of spaces with a point-countable sn-network, establish the mapping relation between spaces with a point-countable wcs*-network of certain property and locally separable metric spaces, and partially correct a gap in [8].

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Abstract  

In this paper the relations among k-covers, cs *-covers and k-systems are discussed. The following question is partially answered: Does every separable k'-space with a point-countable k-system have a countable k-system?

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Abstract  

This article is dedicated to develop an experimental approach for directly visualizing the global freezing phase change behavior of micro liquid droplets. The infrared (IR) thermograph was proposed to image the basic solidification phenomena of droplet and to acquire its temperature variations during the transient process. In particular, the volumetric recalescence event, regarded as initiation of freezing, was revealed by IR images for the first time. Preliminary results demonstrated that the involved temperature transition due to release of the latent heat can be accurately characterized by evident color break in IR images. Further, experiments were also performed simultaneously on three kinds of droplets made of pure water, dimethylsulfoxide (DMSO) and nano liquid to grasp more precise temporal and spatial temperature distribution. Types of the occurring solidification and the initial frozen volume produced from the recalescence were generally discussed. The IR monitoring method suggests a straightforward way for detecting the freezing phase change activity and its temperature evolution at micro scale.

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Abstract  

Blends of known amounts of α- and β-PP crystals were prepared from pure α- and pure β-PPsamples. Their fusion behaviours were studied by differential scanning calorimetry (DSC).The fusion heats of the α- and β-crystals were approximated from the DSC curves and compared with those calculated on the basis of the compositions of the blends. A correction function was found which improved the accuracy of the respective fusion heats significantly from the DSC analysis. The correction function can be used to determine the respective fusion heats of a PP sample which contains an unknown mixture of the α- and β-crystals.

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SOFM (self-organizing feature map) clustering is powerful in analyzing and solving complicated and non-linear problems. This method was used and compared with fuzzy C-means clustering and TWINSPAN, the most common classification methods, in analysis of plant communities in the Guancen Mts., China. The dataset consisted of importance values of 112 species in 53 quadrats of 10 m × 20 m. All the three methods classified the 53 quadrats into eight groups, representing eight associations of vegetation. They were all effective in the analysis of ecological data. The consistency of SOFM clustering with fuzzy C-means clustering (FCM) and TWINSPAN classification was 81.1% and 94.3%, respectively. SOFM clustering has some advantages and more potentiality in application to studies of ecology.

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The Taihang Mountain Range is located at E112°50′–114°30′, N35°20′–39°30′ in North China. This study aimed to reveal relationships between plant communities, soil variables and topographic variables. Floristic data and environmental data from sixty-eight quadrats of 10 m × 20 m along an elevation gradient from 1050 to 2180 m were analysed by TWINSPAN, DCA and CCA. Eight vegetation formations were recognized, all secondary successional stages following the original broad-leaved deciduous forests’ distraction by human activities. The results showed that the community patterns are related to both soil variables and topographic variables. Among the soil variables, soil N, P, K and organic matter were found to be the most important factors forcing the spatial patterns of plant communities. The vegetation patterns were also significantly correlated with the topographic variables, elevation, slope and aspect. Interactions between the environmental variables were significant. It is concluded that further measures for the conservation of vegetation and protection of soils in the Taihang Mountains must be undertaken.

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