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排序方式: 共有998条查询结果,搜索用时 187 毫秒
51.
介绍了与Shell煤气化配套的耐硫变换装置采用重油裂化气开车及运行情况。通过对设计数据与实际运行数据对比以及节能效益与存在的问题分析,指出了该套装置的优越性以及用于Shell粉煤气化原料气变换的可行性。 相似文献
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The aim of this study was to investigate whether total carotenoid content (TCC) in noble scallop Chlamys nobilis is related to body tissue, shell colour, and gender. TCC was determined by a UV–vis recording spectrophotometer in tissue of gonad, adductor, mantle, and gill separately sampled from male and female individuals with orange and brown shell colours from the same cultured population. TCC was significantly different among body tissues, depending on shell colour and gender, ranging from 0.73 to 59.85 μg g−1. In general, TCC was greater in the order of gonad > mantle > adductor > gill. In the same gender, orange shell colour individuals contained significantly higher TCC than brown ones in all four tissues (P < 0.05). In the same shell colour, female contained significantly higher TCC than male in gonad and adductor tissues (P < 0.05). 相似文献
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Edoardo Artioli Lourenco Beirão da Veiga Harri Hakula Carlo Lovadina 《Computational Mechanics》2009,44(1):45-60
We consider the free vibration problem of thin shells of revolution of constant type of geometry, focusing on the asymptotic
behaviour of the lowest eigenfrequency, as the thickness tends to zero. Numerical experiments are computed using two discretization
methods, collocation and finite elements, each corresponding to a different shell model. Our results are in agreement with
theoretical results obtained using interpolation theory and cited in literature. 相似文献
57.
Heidi Van den Broeck Hans De Wolf Ronny Blust 《The Science of the total environment》2009,407(8):3063-3069
In this study we present the results of an intersex survey of Littorina littorea along the Belgian coast. Levels of female intersex and sterility were determined to assess TBT related adverse effects. In addition, we determined the levels of male penis shedding and trematode infestation and investigated the morphology of the shell. Significant differences were found for all these variables which clearly differentiated periwinkles from Zeebrugge (B2) from those at other locations. Intersex index (ISI) values were relatively low (i.e. 0.00-0.39), except at B2 where they ranged up to 3.52, the highest value ever reported in literature. Consequently, female reproductive impairment at B2 was severe. Indeed, up to 95% of female periwinkles were sterile at B2. In addition, 61% of the male periwinkles had shed their penis. Furthermore, no trematode infestation could be detected at B2 and specimens from this location had the largest and heaviest shells, which may be related to population demography and/or a different use of energy budgets. 相似文献
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《Thin》2015
In civil engineering, shell structures are widely used as liquid-containment vessels. Understanding how the shell responds to relevant loading conditions is important for the design of safe and economical liquid-containment shell structures. This paper reviews recent research on the strength, stability and vibration behaviour of liquid-containment shell structures, and traces the developments pertaining to the design of these facilities to withstand various loading and environmental effects such as liquid pressure, wind pressure, ground movement and thermal effects. Results of recent feasibility studies of non-conventional shell forms for liquid containment are also reported, and areas of focus for future research are suggested. 相似文献
59.
《Thin》2015
Liquid storage steel tanks are vertical above-ground cylindrical shells and as typical thin-walled structures, they are very sensitive to buckling under wind loads, especially when they are empty or at low liquid level. Previous studies revealed discrepancies in buckling resistance of empty tanks between the design method proposed by the American Standard API 650 and the analytical formulas recommended by the European Standard EN1993-1-6 and EN1993-4-2. This study presents a comparison between the provisions of current design codes by performing all types of numerical buckling analyses recommended by Eurocodes (i.e. LBA-linear elastic bifurcation analysis, GNA-geometrically nonlinear elastic analysis of the perfect tank and GNIA-geometrically nonlinear elastic analysis of the imperfect tank). Such analyses are performed in order to evaluate the buckling resistance of two existing thin-walled steel tanks, with large diameters and variable wall thickness. In addition, a discussion is unfolded about the differences between computational and analytical methods and the conservatism that the latter method imposes. An influence study on the geometric imperfections and the boundary conditions is also conducted. Investigation on the boundary conditions at the foot of the tank highlights the sensitivity to the fixation of the vertical translational degree of freedom. Further, it is indicated that the imperfection magnitude recommended by the EN1993-1-6 is extremely unfavorable when applied to large diameter tanks. Comments and conclusions achieved could be helpful in order to evaluate the safety of the current design codes and shed more light towards the most accurate one. 相似文献
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