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  • Author or Editor: Li Lin x
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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  

To order to examine experimentally the modified monostandard method implemented in the program MULTINAA, the FRM reactor in Garching (Germany) was calibrated and an INAA of a standard reference material NIST/SRMI1633b Coal Fly Ash was performed. The relative, thek 0-and the modified monostandard standardizations are applied. This work shows that for all of the examined 1/-nuclides the modified monostandard method provides identical analytical results to those determined by thek 0-method. For the non-1/ nuclides177Lu and152Eu the monostandard results are correct. Compared with the certified values of the analysed SRM1633b sample and also with the results of the relative method, it can be concluded that the modified monostandard method performed at our experimental conditions gives analytical results with accuracy better than 5%.

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Abstract  

A number of generalized metric spaces have been defined or characterized in terms of g-functions. Symmetric g-functions are discussed by C. Good, D. Jennings and A. M. Mohamad. In this paper, some questions about symmetric g-functions are answered, particularly it is shown that every sym-wg-space is expandable.

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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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The problem when a paratopolgical group (or semitopological group) is a topological group is interesting and important. In this paper, we continue to study this problem. It mainly shows that: (1) Let G be a paratopological group and put τ = ω H s(G); then G is a topological group if G is a P τ-space; (2) every co-locally countably compact paratopological group G with ω H s(G) ≦ ω is a topological group; (3) every co-locally compact paratopological group is a topological group; (4) each 2-pseudocompact paratopological group G with ω H s(G) ≦ ω is a topological group. These results improve some results in [11, 13].

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Abstract  

A compute program MULTINAA was developed to facilitate the evaluation of NAA data. It is written for the VAX/VMS syste and opeates in the Canberra/ND Genie spectroscopy software environment. MULTIINAA can be appliede to relative,k 0-, monostandard (modified) and absolute methods, including the fast neutron threshold reaction. For each calculation, the available standardizations can be used individually or mixed. In all the standardization modes MULTINAA fetches the data directly from the -ray spectra and libraries, thus reducing the manual work to a minimum. MULTINAA is flexibkle to meet various situations in NAA practical work. The required neutron flux parameters all the non-relative methods are supplied by an accompanying program MULTIFLUX.

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Abstract

The thermal decomposition of copper(II) acetate monohydrate (CuAc2·H2O) under 500 °C in air was studied by TG/DTG, DTA, in situ FTIR and XRD experiments. The experimental results showed that the thermal decomposition of CuAc2·H2O under 500 °C in air included three main steps. CuAc2·H2O was dehydrated under 168 °C; CuAc2 decomposed to initial solid products and volatile products at 168–302 °C; the initial solid products Cu and Cu2O were oxidized to CuO in air at 302–500 °C. The copper acetate peroxides were found to form between 100 and 150 °C, and the dehydration of these peroxides resulted in the presence of CuAc2·H2O above 168 °C. The initial solid products were found to be the admixture of Cu, Cu2O, and CuO, not simply the single Cu2O as reported before. Detailed reactions involved in these three steps were proposed to describe the complete mechanism and course of the thermal decomposition of CuAc2·H2O in air.

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In this paper, we characterize k-semi-stratifiable spaces by semi-continuous functions and give some applications. Also we give the similar characterizations of MCM spaces and K-MCM spaces.

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Abstract  

Effects of nano-metal powders (aluminum and nickel) addition on the thermooxidative degradation of binder PEG in air atmosphere from 20 to 350°C were studied by TG/DTA and in-situ FTIR. TG/DTA results showed that the addition of nano-Al slowed down the degradation process of PEG in the early period but accelerated the process in the late period; the addition of nano-Ni made the PEG degradation process begin as soon as melted. The in-situ FTIR results showed that nano-Ni promoted the thermooxidative degradation of PEG in air, and made the degradation process of PEG complete much earlier.

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Abstract  

The enthalpies of dilution of matrine (MAT) in pure water and aqueous sodium chloride solutions were determined by isothermal titration microcalorimetry at 298.15 K, and the corresponding homogeneous enthalpic interaction coefficients were calculated according to the modified McMillan–Mayer model. The values of enthalpic pair-wise interaction coefficients, h 2, are all positive and become more positive with increasing concentration of sodium chloride.

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