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Hydrogenation of four bituminous coals impregnated with 5 wt% of either mixtures of ZnCl2-MCln (CuCl, CrCl3 and MoCl5) systems or ZnCl2 was carried out using a batch autoclave system at 400° for 3 h at 9.8 MPa of initial hydrogen pressure. The ZnCl2-MoCl5 system showed the highest yield of the hexane-soluble (HS) fraction compared with the other systems irrespective of the coal used. The difference between the yields of HS fractions using the ZnCl2-MoCl5 and other systems was most marked for coals of fairly low volatile matter content, though the conversion was relatively low (47–66%), whilst for coals of high volatile matter content HS yields with the binary melt systems were high (86–91% conversion). Elemental analyses of the HS fractions indicated that the ZnCl2-MoCl5 system is most favourable in decreasing the average molecular weight and the heteroatom content of HS, this characteristic trend being confirmed also with five HS fractions separated by Chromatographic techniques. Both elemental analyses and molecular weights of asphaltene (benzene-soluble materials, BS) indicated that the ZnCl2-MoCl5 system is also most effective in cracking coal structure. 相似文献
3.
Akihiko Nagata Osamu Izumi Kōshichi Noto Hiroshi Hirayama 《Journal of Materials Science》1978,13(4):731-738
The dilute Cu-Nb-Sn alloys containing small amounts of Nb and Sn less than 1 at % exhibited superconductivity after quenching from the liquid state and ageing. The best superconducting properties (
andJ
c=130 A cm–2) in a Cu-0.30 at % Nb 0.15 at % Sn alloy were obtained when the sample was aged at 550° C for 384 h. This sample exhibited a structure of fine Nb3Sn precipitates of 200 to 500Å diameter distributed homogeneously in the Cu matrix, and therefore it was concluded that superconductivity in these alloys resulted from the proximity effect of Nb3Sn particles. In spite of the similar structure obtained by ageing at 800° C, the Cu-Nb-Sn alloys showed inferior superconducting properties compared to the Cu-0.4 at % Nb alloy and this would be explained qualitatively by the difference in the mean free path in the two alloys. 相似文献
4.
<正> 孔蚀的发生与发展既受材料因素的制约,又受环境条件的影响。由于小孔在生长过程中其总表面积一直在变化,直接测定小孔生长速度十分困难,因此有人采用人工小孔模型以研究小孔的生长规律。本工作采用人造小孔模型系统研究了环境因素对碳钢单蚀孔阳极溶解的影响规律及蚀孔内表面膜的组成与作用。 相似文献
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6.
I Got 《Canadian Metallurgical Quarterly》1998,24(4):379-384
The aim of this study was to assess sleep and pulmonary function in asthmatic and control children. Forty children with well-controlled, stable asthma, and 34 controls (age range: 8.2 to 15.4 years) were monitored with wrist actigraphs and peak-flow meters for 3 consecutive days. In addition, asthma severity was assessed by subjective parental and self-rating scale and symptom checklist. Asthmatic children had poorer sleep quality in comparison to their controls, as manifested in lower percentages of quiet sleep (p < .05) and increased activity level during sleep (p < .05). As expected, asthmatic children had reduced morning peak expiratory flow measures (p < .01) and a higher evening-to-morning drop in peak expiratory flow (p < .005). Peak-flow measures were significantly correlated with subjective and objective sleep measures. In the asthmatic group, sleep measures were also correlated with subjective asthma severity indices and symptom checklists. We conclude that poorer sleep is associated with reduced pulmonary function. The reduced sleep quality, coupled with subjective reports of increased fatigue and reduced alertness found in asthmatic children, suggest that these children are at risk for developing neurobehavioral deficits associated with chronic sleep loss. 相似文献
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This is a review and an overview on hydrothermal synthesis of fine oxide powders. The term hydrothermal today includes methods
which involve water at pressures (from 1 atm-several kilobars) and high temperatures from 100–10,000°C. Hydrothermal is one
of the best methods to produce pure fine oxide powders. The authors describe (i) hydrothermal decomposition, (ii) hydrothermal
metal oxidation, (iii) hydrothermal reaction, (iv) hydrothermal precipitation and hydrothermal hydrolysis, (v) hydrothermal
electrochemical, (vi) reactive electrode submerged arc, (vii) hydrothermal microwave, (viii) hydrothermal sonochemical, etc
and also ideal and real powders 相似文献
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