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91.
Gasification reactivities of cokes with carbon dioxide, steam and their mixtures at 1200 °C were investigated, using seven single cokes made in a laboratory furnace from single coals of different properties, and also one commercial coke. The reactivity with steam was significantly higher than that with carbon dioxide. The reactivities of the mixture increased proportionally with increasing steam content above 10%; however, the reactivity below 10% steam content was smaller than that with pure carbon dioxide, the minimum reactivity being observed at a steam content of 2–4%. The reactivities of the compounds corresponding to optical texture were determined by analysing the coke microscopically before and after gasification. In general, except for one coke, the inert texture was the most reactive. Increasing size of the optical unit decreased the gasification reactivity, fibrous and leaflet textures were the least reactive. Gasification with steam developed pores within the inner region of the coke, whereas carbon dioxide reacted with the coke at or near the surface, producing a relatively smooth surface. Some proposals are suggested for better coke production. 相似文献
92.
In order to gain an insight into creep crack propagation problems a mechanics approach is presented in this paper on the basis of the plastic singular stress field near a crack tip under the Mode III and I steady-state creep conditions, in combination with a generalized creep damage hypothesis. Closed form equations which predict rates of creep crack propagation are obtained analytically. According to this analysis, it is found that is the index which characterizes the effect of damage accumulation in front of a crack, where n is the creep exponent and b1 is the exponent involved in the creep damage hypothesis used in this analysis. The tendency of the predicted crack propagation behaviors is consistent with experimental data available in the literature. 相似文献
93.
In the galvanic corrosion, the distribution of potential within the electrolyte was calculated for the condition that each local cell is independent and there is no interaction between the local cells. This analysis on the problem extended the Waber's treatment, and the distribution of potential was obtained for each local cell. 相似文献
94.
Interdiffusion was studied in the temperature between 974 and 1273 K, using conventional sandwich-type diffusion couples consisting
of pure copper and Cu-2.1 at. pct Ag alloy. The interdiffusion coefficient,
, increased slightly with increasing the atomic fraction of silver, NAg. Values of
were well represented by the parameters of
0 = 0.21 x 10-4 (m2/s) and ≈
= 184.5 - 143.0 NAg (kJ/g-atom) up toNAg = 0.02. The Kirkendall effect during diffu-sion treatments at 1174 K for up to 1.4724 x 106 s was also studied. The marker moved always toward the silver-rich side. The ratio, D*Ag / D*Cu,was 5.6 for NAg = 0.011, while it was 4.2 for NAg = 0. 相似文献
95.
The crystal structures of two PbSb2O6-type compounds containing titanium, CdTi2O4(OH)2 and LaTiSbO6 were refined by X-ray powder diffraction data. For both compounds structure refinements with the space group were successful and the R-factors were RWP = 6.46% and RP = 4.90% for CdTi2O4(OH)2 and RWP = 9.55% and RP = 7.17% for LaTiSbO6. These crystal structures were the same as that of the typical PbSb2O6-type compound in spite of the existence of protons in the interlayer or two different metal ions in the layer. 相似文献
96.
Pressureless sintering of SiC was accomplished at 2100°C with oxide additives. These additives were the products of the reaction of Al(OH)3 with HCl and of Y(OH)3 with HCOOH. These reaction products were dissolved in water and mixed with submicrometer β-SiC. A mixture of equal weights of these additives was effective for the sintering of SiC. 相似文献
97.
Summary This paper describes No-Catalyst Copolymerizations between ethylene phenylphosphonite (EPO) as MN and four -hydroxyalkyl acrylates and methacrylates as ME. In all combinations polyphosphinate type copolymers were obtained above 130 °C without added catalyst. The first step of reaction was a proton-transfer step to yield a transient phosphonium-alkoxide zwitterion 5 and generated a phosphorane intermediate like 6. The subsequent reactions of 6 were rather complicated. It was possible to conceive several zwitterions to lead to polymer units. The liberation of ethylene oxide and/or propylene oxide was observed as a side reaction during polymerization.Dedicated to the 60th birthday of Professor C. I. Simionescu 相似文献
98.
99.
100.
H Tsutsumi N Matsui Y Morita E Sano K Okamura T Komuro T Takei 《Canadian Metallurgical Quarterly》1993,47(6):466-480
Plaster models of the teeth of 3-year-old Japanese children (96 males, 98 females) were used to record the crown length, crown width and crown thickness of 5 maxillary and 5 mandibular deciduous teeth (30 measurement values). These measurements were used to devise a number of sex determination formulae. A sex-determination formula using all 30 values was calculated. Furthermore, a number of practical formulae were derived from only the crown width and crown thickness values because the deciduous teeth wear in 4 years and older children rapidly progress, making the crown length measurement unreliable. These formulae were calculated for the maxillary teeth alone and mandibular teeth alone. The formulae based on only the crown width or thickness were also calculated for both maxillary and the mandibular teeth. A step-wise discriminant analysis was then used to ascertain the most reliable measurements and a practical formula subsequently devised. The results obtained were as follows: 1. The mean value for each measurement was greater in males than in females. 2. Significant differences in the values recorded were seen in 28 out of the 30 measurements taken. The measurement items not exhibiting these significant differences were the crown width of the maxillary lateral incisor and the crown thickness of the mandibular second molar. 3. The accuracy rates for the sex-determination analysis and the step-wise sex determination analysis calculated using all 30 values were 78.6% and 75.7%, respectively. 4. The accuracy ranges for the modified sex-determination formulae and the associated step-wise sex determination analyses were 70.6-78.4% and 67.0-76.8%, respectively. 相似文献