Results 21 to 30 of about 32,077 (249)
Rare Metals, EarlyView.ABSTRACT Photocatalytic molecular oxygen (O2) activation provides a sustainable approach to produce singlet oxygen (1O2) for organic contaminants detoxification. However, the charge carriers‐involved pathway usually suffers from unsatisfactory 1O2 production efficiency owing to energy loss caused by photogenerated hole‐mediated superoxide species (•O2−
Yan‐Biao Shi +8 more
wiley +1 more source
Gaoya dianqi, 2017 绝缘子泄漏电流能够综合体现绝缘子电压水平、污秽状态,贯穿于绝缘子的整个闪络发展过程,提取绝缘子泄漏电流特征量对预测绝缘子闪络事故的发生尤为重要。在人工污秽试验的基础上,利用分形理论提取了复合绝缘子泄漏电流分形维数特征量,分析了闪络发展过程中泄漏电流不同区段波形和分形维数的变化特征,对比了3种不同污秽度水平下泄漏电流波形的分形特征。结果表明,在污闪发展过程中,泄漏电流波形的分形维数呈整体下降的趋势;污秽程度不同,泄漏电流波形分形特征存在微小的差异。实验分析证明,泄漏电流波形分形维数能够直接反映其波形特征 ...
秦莉娟 +5 more
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Shuitu Baochi Xuebao, 2020 通过野外径流小区人工降雨试验，研究坡形和聚丙烯酰胺（PAM）对径流量、土壤侵蚀和养分流失的影响。试验设置2个PAM施用量，分别为0，2 mg/L；9种坡形处理，即4个凹形坡，4个凸形坡，1个直形坡。结果表明：（1）与均匀坡面相比，凸形坡的平均土壤流失量、氨氮流失量和磷酸盐流失量分别增加25.12%，24.01%和26.96%，且土壤和养分流失量随着凸形坡面的凸度增加而增加，凹形坡的平均土壤流失量、氨氮流失量和磷酸盐流失量分别减小13.53%，10.85%和19.95%；（2 ...
邢伟民 +4 more
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Rare Metals, EarlyView.ABSTRACT Nb‐Si‐based superalloys are considered as the most potential candidate materials for nickel‐based superalloys due to the lower density and higher using temperature. Here, a type of stable Nbss/γNb5Si3 bi‐phases structure with a coherent interface has been successfully designed. Additionally, the Nbss and γNb5Si3 phases showcase the orientation
Xiao‐Wei Wang +6 more
wiley +1 more source
Shuitu Baochi Xuebao, 2007 以8个植被类型、2个农地和2个退耕地的土壤颗粒组成数据为基础，运用分形模型计算这12个土地利用类型土壤颗粒的分形维数，研究了土壤颗粒分形维数与土壤性状的关系。结果表明：（1）12个土地利用类型表层土壤颗粒的分形维数介于2．8185～2．9249之间。与退耕地和玉米地相比，各林地土壤颗粒分形维数小；与1990年的2．8633相比，2006年土壤颗粒分形维数（2．8592）减小；各团聚体分形维数规律不明显。（2）决定土壤颗粒分形维数大小的首先是〈o．002mm的含量，其次是0．05～0．25mm和0 ...
李进峰 +4 more
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Rare Metals, EarlyView.ABSTRACT Rare earth elements (REEs) play an irreplaceable role in modern technology and industry. However, due to the highly similar physicochemical properties among REEs, their separation remains a significant challenge. Additionally, REEs often exist in low‐concentration solutions, making efficient REE recovery an urgent task.
Miao‐Miao Huang +6 more
wiley +1 more source
Rare Metals, EarlyView.ABSTRACT With the rapid development of the energy storage industry, aqueous zinc‐ion batteries (AZIBs) have attracted considerable attention in the field of energy storage because of their inherent advantages, thereby emerging as a promising research direction with significant potential.
Lingjiao Fu +8 more
wiley +1 more source
Shuitu Baochi Xuebao, 2005 应用VanGenuchten提出的土壤水分特征曲线公式,推导出了沙漠风沙非饱和土壤水分特征曲线的分形模型。通过对古尔班通古特沙漠地9种不同土壤样本利用中子水分仪和负压计实测的水分特征曲线资料反求得到相应的分形维数,分析了分形维数与土壤质地之间的关系,结果表明随着土壤质地从流动风沙土、半固定风沙土到固定风沙土的变化,其分形维数呈逐渐增大。此外,基于土壤颗粒的重量与粒径分布求出了古尔班通古特沙漠地风沙土壤粒径的分形维数。通过对土壤水分特征曲线的分形维数与土壤粒径的分形维数的对比 ...
苏里坦 宋郁东 张展羽
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Numerical Analysis of the Time Fractional Black-Scholes Equation [PDF]
, 2016 时间分数阶Black-Scholes方程在期权定价中有着日益广泛的应用。本文旨在研究该方程的数值解法，构造和分析了两个有效算法。第一个算法结合了时间方向的有限差分和空间方向的谱方法；第二个方法则基于时空Galerkin谱方法。通过引入恰当的Sobolev空间，我们构建了时空变分问题，证明了时空弱问题的适定性。在算法分析方面，我们首先给出两种方法的最优误差估计。然后讨论算法实现技巧，通过选取适当的基函数导出离散问题的线性系统。最后给出一些数值例子验证理论结果。The time fractional ...
刘瑞清
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