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51.
52.
《国际计算机数学杂志》2012,89(3-4):381-397
In this paper, more accurate solutions are obtained by applying the Numerov formula to the Alternating Group Explicit (AGE) method in the solution of linear and non-linear two point boundary value problems. 相似文献
53.
为改善V2O5薄膜的电致变色性能,采用溶胶-凝胶法将具有高离子电导率并具有水溶性的聚环氧乙烷(PEO)直接嵌入V2O5层间,制备了PEO/V2O5纳米复合薄膜。采用标准三电极法从0.5mol/L LiClO4的PC电解质溶液向PEO/V2O5纳米复合薄膜注入锂离子,测量了纳米复合薄膜在注入不同数量锂离子时的可见光透射光谱以及对应的颜色变化,并运用循环伏安法测试其电化学性能。实验结果表明,PEO/V2O5纳米复合薄膜的循环伏安图出现了2对氧化还原峰,并且具有稳定的循环可逆性。随着应用电压的不同,薄膜呈现黄色、绿色和蓝色的多色可逆变化。PEO/V2O5纳米复合薄膜的电化学稳定性和机械性能都优于V2O5干凝胶薄膜,可以作为电致变色材料得到应用。X射线光电子能谱(XPS)成分分析表明PEO/V2O5纳米复合薄膜的电致变色效应与V、O的化合价和化学环境密切相关。 相似文献
54.
C.T. Chang Y.C. Du R.K. Shiue C.S. Chang 《Materials Science and Engineering: A》2006,420(1-2):155-164
Microstructures and fracture behaviors of infrared heated, vacuum brazed Ti–6Al–4V and Ti-15-3 alloys using two Ti–Cu–Ni braze fillers have been characterized to establish the effects of brazing process parameter and chemical composition on the strength of brazed joints. The brazed joint initially contains two prominent phases; a Ti alloy matrix alloyed with V, Cr, Ni, Cu and Al and a Cu–Ni-rich Ti phase. Brazing temperature and soak time control the amount of Cu–Ni-rich Ti phase in the brazed joints. The fracture mode changes from brittle cleavage to quasi-cleavage to ductile dimple as the amount of Cu–Ni-rich Ti phase is reduced in the brazed joint. Both brazing temperature and soak time are critical to eliminate the Cu–Ni-rich Ti phase for optimal shear strength and ductile fracture of brazed joints. A post-brazing annealing at lower temperature is also shown to be an effective way to homogenize the microstructure of brazed joint for improved joint strength. 相似文献
55.
周筝 《成都电子机械高等专科学校学报》2006,(2):34-36
可再生能源需要性能优良的储能电池与之配套,因此,研究和开发价廉、高效率的储能系统是十分必要的。本文通过介绍钒氧化还原液流电池的原理和特点,指出钒电池是一种潜力巨大的新型环保储能电池。同时介绍钒电池制备和应用时的三大技术关键及一定的解决方法。 相似文献
56.
Investigations of ferritic/martensitic super heat resistant 11‐12 %Cr steels for 650 °C power plants
The investigations of advanced ferritic/martensitic 11–12 %Cr steels for 650 °C power plant components focus on the improvement of high‐temperature creep properties with respect to chemical composition. The claim of the DFG research work was the development of new heat‐resistant 12 %Cr ferritic‐martensitic steels with sufficient creep and oxidation resistance for a 650 °C application by using basic principles and concepts of physical metallurgy on the basis of the state of art and to overcome the usual trial and error industrial alloy development. Efforts are focussed on a 100,000h creep strength of 100MPa at 650 °C in combination with a sufficient corrosion resistance by a Cr content of 12 % with contents 4‐5 %W, 3.4‐5,5 %Co, V, B and 1 %Cu as well as the choice of Ta or Ti instead of Nb. The results demonstrate that the aim is not to realize with the used alloying concept. In the long term range all 12 %Cr melts have a lower creep rupture strength than the advanced 9 %Cr piping steel P92. A high creep strength could be reached with a 0.06 % Ta alloyed 11 %Cr melt, which is in addition alloyed with a higher C and B content and as well as with lower W and Co portions. The results indicate in accordance with the finding of other steel researcher that a lower Cr content allows more effectiveness for the alloying partners respectively for the generation of more stable precipitates. 相似文献
57.
58.
The fatigue crack growth behaviors of Laser formed and ingot metallurgy (IM) Ti–6Al–4V alloys were studied in three environments: vacuum, air and 3.5% NaCl solution. Taking the Unified Fatigue Damage Approach, the fatigue crack growth data were analyzed with two intrinsic parameters, stress intensity amplitude ΔK and maximum stress intensity Kmax, and their limiting values ΔK* and . Fatigue crack growth rates da/dN were found increase with stress ratio R, highest in 3.5% NaCl solution, somewhat less in air and lowest in vacuum, and higher in IM alloy than in Laser formed one. In 3.5% NaCl solution, stress corrosion cracking (SCC) was superimposed on fatigue at R=0.9 for where Kmax>KISCC, the threshold stress intensity for SCC. This and environment-assisted fatigue crack growth were evidenced by the deviation in fatigue crack growth trajectory (ΔK* vs. curve) from the pure fatigue line where . Furthermore, the fractographic features, identified along the trajectory path, reflected the fatigue crack growth behaviors of both alloys in a given environment. 相似文献
59.
Several V-W-Ti alloys with about 50% reduction in thickness by cold rolling were isochronally annealed at temperatures from 100 to 1100 °C. Hardness was measured after the annealing. By comparison with V4Cr4Ti and V4Ti alloys, the V6WTi alloy was found to begin recovery at a temperature about 100 °C higher, while the full recrystallization temperature was around 900 °C for all of the alloys. Hardness decreased successively above 500 °C in V8W, as is the case in pure V. Impurity induced hardening was observed around 300 °C only in the alloys without Ti. Precipitation and the interaction between interstitial impurities and dislocations were supposed to be the main contributors to the different recovery and recrystallization behaviors of the alloys. 相似文献
60.
橡塑磁条在永磁音像微特电机中的应用 总被引:1,自引:0,他引:1
本文简述了橡塑磁条的制造工艺及在永磁音像电机规模生产中的应用,与铁氧体烧结磁环进行比较,阐述了橡塑磁条在音像微特电机中使用的优势。 相似文献