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81.
Yanhong Ding Tian QiuXuan Liu Yi LongYongqin Chang Rongchang Ye 《Journal of magnetism and magnetic materials》2006
Under various amplitude of AC magnetic fields domain wall motion is the main mechanism in the magnetization process. This includes domain wall bulging and domain wall displacing. In this paper complex permeability-frequency spectra of (Fe1−xCox)73.5Cu1Nb3Si13.5B9 (x=0,0.5) nanocrystalline alloys were measured as a function of the AC magnetic field, ranging from 0.001 to 0.04 Oe. Obvious changes have been found in complex permeability spectra for alloy x=0 with the change of the amplitude of AC magnetic field, but variation of AC magnetic field has little effect on complex permeability spectra for alloy x=0.5. This is attributed to the increased pinning field after substitution of Fe with Co in Fe73.5Cu1Nb3Si13.5B9 nanaocrystalline alloy. 相似文献
82.
李艳红 《浙江大学学报(理学版)》2014,41(2):127-131
通过减弱公理化条件给出新拟乘算子, 并按照拟乘运算针对实函数正(负)部建立了广义拟Sugeno模糊积分. 依据演化的确界概念获得了该积分的3种表达形式, 并给出了其等价表示及其证明. 最后, 通过实例验证了该广义拟Sugeno模糊积分3种等价表示的正确性. 相似文献
83.
近年来,用人单位对高校毕业生工程实践能力的要求越来越高,同时为了提升测控技术与仪器专业学生的综合素质以及就业质量,提出了"贝赛(BASI)"实践教学体系.本文重点阐述该体系的构建与特点.该体系的实践,不仅提高了学生对动手实践的兴趣与积极性,而且培养了学生的工程实践能力以及团队合作能力. 相似文献
84.
Yanhong Liu Yan Fu Jing Wang Bingchun Xue Erbao Liu 《Russian Journal of Physical Chemistry B, Focus on Physics》2017,11(5):722-728
The pKa values of some phthalhydrazide derivatives were calculated using ab initio and two density functional methods to obtain information about their reaction conditions. The results showed that pKa1 was influenced by structural modification as it varied between 0.47 and 6.99, and that pKa2 was relatively less variable from 16.66 to 21.53. The high values of pKa2 revealed that a strong alkaline solution was necessary for all chemiluminescent reactions of discussed phthalhydrazide derivatives. 相似文献
85.
生物质燃烧向大气中排放大量颗粒污染物, 在中国, 收获季节大量秸秆被直接露天燃烧处理, 对区域环境质量和人体健康造成严重影响. 对我国最主要的两种粮食作物玉米和小麦秸秆的露天燃烧进行模拟, 分析颗粒物排放水平, 特征及影响因素. 玉米和小麦秸秆燃烧PM2.5排放因子分别为1082.8和835.7~897.3 mg/kg. 有机物是颗粒物最主要组分, 总量占PM2.5质量的42%~66%. Cl-和K+分别占PM2.5总质量的4%~15%和2%~14%, K+/EC值为0.5~3.8. 各物种在颗粒物中所占比例与之前研究结果一致. 秸秆含水量和燃烧温度影响PM2.5排放水平和组成特征. 随秸秆含水量增加, PM2.5和OC的排放因子增加; 秸秆含水量增加, 燃烧温度逐渐降低, 由生物质燃料释放进入烟气中的K+和Cl-比例逐渐减小导致二者在颗粒物中的比例降低. 我国每年由玉米和小麦秸秆露天燃烧排放的PM2.5和OC分别为92.7 Gg和47.5 Gg, 在总量中占重要比例. 相似文献
86.
The novel 1,2‐diaryl substituted pyrrolo[3,4‐b]pyridine‐5,7‐diones were selectively synthesized in high yields by the base catalyzed cyclization reaction of 3‐arylamino‐1‐methyl‐1H‐pyrrole‐2,5‐diones with cinnamaldehyde and its derivatives in acetonitrile at room temperature. However, when piperidinium trifluoroacetate was employed as catalyst, the reaction afforded a mixture of 1,2‐diaryl and 1,4‐diaryl substituted pyrrolo[3,4‐b]pyridine‐5,7‐diones in comparable yields. 相似文献
87.
A computationally efficient quantitative phase field formulation is used to investigate the sidebranching dynamics under different transient conditions in directional solidification for realistic parameters of a dilute alloy. The sidebranch growths where the pulling speed or temperature gradient increases with constant increasing rates are simulated and discussed by using the noise amplification theory. The results show that in transient growth, the tip shape can rapidly adjust with the instantaneous conditions, and the tip velocity changes continuously due to the change of tip undercooling. Therefore, under our given transient conditions, the sidebranch spacing or sidebranching frequency depends strongly on the transient conditions and transient history, which is different with that in steady‐state conditions where the sidebranching frequency is found to be independent of the temperature gradient and primary spacing, but varies as a power law of pulling speed. 相似文献
88.
89.
Wenjuan Hao ;Hanhui Zhan ;Han Chen ;Yanhong Wang ;Qiangqiang Tan ;Fabing Su 《Particuology》2014,(4):18-26
Layered Li[Li0.2Mn.56Ni0.6Co0.08]O2 cathode materials were synthesized via a solid-state reaction for Liion batteries, in which lithium hydroxide monohydrate, manganese dioxide, nickel monoxide, and cobalt monoxide were employed as metal precursors. To uncover the relationship between the structure and electrochemical properties of the materials, synthesis conditions such as calcination temperature and time as well as quenching methods were investigated. For the synthesized Li[Li0.2Mn.56Ni0.6Co0.08]O2 materials, the metal components were found to be in the form of Mn4+, Ni2+, and Co3+, and their molar ratio was in good agreement with stoichiometric ratio of 0.56:0.16:0.08. Among them, the one synthesized at 800 ℃ for 12 h and subsequently quenched in air showed the best electrochemical performances, which had an initial discharge specific capacity and coulombic efficiency of 265.6 mAh/g and 84.0%, respectively, and when cycled at 0.5, 1, and 2 C, the corresponding discharge specific capacities were 237.3, 212.6, and 178.6 mAh/g, respectively. After recovered to 0.1 C rate, the discharge specific capacity became 259.5 mAh/g and the capacity loss was only 2.3% of the initial value at 0.1 C. This work suggests that the solid-state synthesis route is easy for preparing high performance Li[Li0.2Mn0.56Ni0.16Co0.08]O2 cathode materials for Li-ion batteries. 相似文献
90.
Kinetic hydrate inhibitor performance of new copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s with TBAB 总被引:1,自引:0,他引:1
In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed. 相似文献