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101.
102.
《International Journal of Hydrogen Energy》2020,45(52):28163-28174
Element replacement and mechanical milling are considered as the most effective ways to improve Mg-based alloys in their hydrogen storage performance. The as-milled La7RE3Mg80Ni10 (RE = Sm, Ce) alloys were prepared in this experiment by introducing both element replacement (replacing La by Ce or Sm partially) and mechanical milling technologies. The influence made by different replacing elements on the structure and hydrogen storage property of La7RE3Mg80Ni10 (RE = Sm, Ce) alloys was investigated in detail. X-ray diffraction, transmission electron microscope, automatic Sievert apparatus, thermogravimetry and differential scanning calorimetry were used to investigate the experimental alloys. The experiment reveals that a nanocrystalline and amorphous structure appears after mechanical milling. Moreover, comparing with the RE = Sm alloy, the RE = Ce alloy has a superior hydrogen desorption property, including larger hydrogen absorption capacity, faster hydriding/dehydriding rate, lower onset hydrogen desorption temperature, and lower dehydrogenation activation energy. 相似文献
103.
Jingli Yan Yangshan Sun Feng Xue Shan Xue Yingying Xiao Weijian Tao 《Materials Science and Engineering: A》2009,524(1-2):102
A binary magnesium alloy, Mg–2 wt.%Nd, has been prepared. Under the condition of temperature between 150 and 250 °C and applied stress between 30 and 110 MPa, the alloy exhibits good creep resistance due to both solution-hardening and especially precipitation-hardening. Tiny precipitates forming dynamically during creep have been observed, which play an important role in restricting dislocation movements. When the creep tests are carried out at the temperature range between 150 and 250 °C, the stress exponents lie in the range of 4.5–7.1 at low stresses, which is consistent with the “five-power-law”. The values of stress exponent increase up to 9.8–29.5 at high stresses indicate power-law breakdown. When the creep tests are carried out under the applied stress between 30 and 90 MPa, the apparent activation energy values vary from 70.0 to 96.0 kJ/mol at low temperatures, but increase to 199.9–246.1 kJ/mol at high temperature range. Dislocations in basal plane are activated in the primary creep stage, but as creep goes on, they are observed in non-basal plane. The creep is mainly controlled by both dislocation-climb and cross-slip. 相似文献
104.
105.
Energy of activation (Ea) and specific heat capacity (Cp) for mixtures of sulphide minerals that on their own do not self-heat (SH), sphalerite/pyrite, pyrite/galena, chalcopyrite/galena and sphalerite/galena, were determined using a self-heating apparatus at temperatures below 100 °C in the presence of moisture. The mixtures all gave Ea ranging from 22.0 to 27.8 kJ mol−1, similar to the range reported for Ni- and Cu-concentrates. The Ea is close to that for partial oxidation of H2S which adds to the contention that the partial oxidation of H2S contributes to SH of sulphides at low temperature. The Cp values ranged from 0.152 to 1.071 JK−1 g−1 as temperature rose from 50 °C to 80 °C, similar to the reported findings on Ni- and Cu-concentrates. The role of galvanic interaction in promoting SH is tested by examining correlations with the rest potential difference of the sulphides in the mixture. 相似文献
106.
Gabriel Loget Janine Carvalho PadilhaEmilse Agostini Martini Michèle Oberson de SouzaRoberto Fernando de Souza 《International Journal of Hydrogen Energy》2009
Different electrodes (nickel, molybdenum, and iron alloys containing chromium, manganese, and nickel) were tested as cathodes for the hydrogen evolution reaction (HER) using 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF4) ionic liquid (IL) as the electrolyte. HERs were conducted at room temperature, at a cathodic potential of −1.7 V (PtQRE) using 10 vol.% aqueous BMI.BF4 solutions. Reactions performed in a thermostated Hoffman cell gave current densities between 14.6 and 77.5 mA cm−2 and efficiencies in the range 97.0–99.2%. Mo electrocatalysts in IL have been shown to be better than Pt, contrary to the classic behavior observed in an aqueous KOH medium. The electrochemical properties of molybdenum, as well as its resistance to corrosion (studied by Tafel plots and observed using SEM) indicate the potential use of this material as a cathode in an IL medium, which can lead to many attractive technological applications. 相似文献
107.
罗巨涛 《浙江理工大学学报》1991,(3)
本文采用自制的双氧水活化剂,在低温下对棉织物进行双氧水漂白,用中心旋转法并借助微机对漂白工艺进行优化。结果表明,此工艺是可行的,当漂白在70℃进行时,漂白效果优于常规气蒸漂白,而与常规浸漂相似。中心旋转法和回归分析是寻找染整工艺优化区域最为有效的方法之一。 相似文献
108.
109.
Cs、O激活方式对GaAs光电阴极的影响 总被引:1,自引:2,他引:1
利用自行研制的GaAs光电阴极多信息量测试与评估系统,比较了不同Cs、O激活方式下GaAs光电阴极的激活过程、光谱响应特性以及稳定性的差异,发现与传统的Cs源、O源交替断续激活方式相比,Cs源持续,O源断续的激活方式能获得灵敏度更高和稳定性更好的阴极,且阴极的长波响应能力也得到提高.本文利用双偶极层模型对实验现象进行了解释,认为Cs在整个激活过程中处于轻微过量状态有利于获得高性能的GaAs光电阴极,Cs量控制是决定GaAs光电阴极激活工艺好坏的主要因素. 相似文献
110.
二氧化锰活化工艺探索 总被引:1,自引:0,他引:1
本文以“EMD电解液+少量NaClO_3和含铝聚氯化物”为介质的活化体系为基础,试验并确定活化MnO_2的工艺条件。 相似文献