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51.
Based on nonlinear wave mixing, we experimentally propose a scheme for directly generating optical orbital angular momentum(OAM) by a spirally structured fundamental wave interacting with a nonlinear medium, in which the nonlinear susceptibilities are homogenous. In the experiment, the second-harmonic generation of a fundamental wave carrying positive(negative) integers and fractional OAM states was investigated. This study presents a convenient approach for dynamic control of OAM of vortex beams, which may feature their applications in optical manipulation and optical communication. 相似文献
52.
TIG焊外加间歇交变纵向磁场的数值计算 总被引:3,自引:0,他引:3
针对奥氏体不锈钢TIG焊接时,与电极同轴的单个轴对称空心圆柱线圈在双向脉冲矩形励磁电流作用下产生的间歇交变纵向磁场,采用无瑕点单积分磁场的数学模型,对TIG焊外加间歇交变纵向磁场进行了数值计算,该方法具有模型简单,计算速度快和精度高等优点,在此基础上,讨论了该间歇交变纵向磁场的分布,磁场的均匀性及其纵向分量与横向分量的比率等规律,为深入研究外加磁场对TIG焊的影响奠定了良好的基础。 相似文献
53.
分别运用最小二乘法、时间序列分析对寿险市场进行了实证研究。与已有的研究相比,通过建立多元线性模型和改进的回归模型,说明国内生产总值的增长是寿险需求增长的根本原因,教育水平的提高和赡养(抚养)率对寿险需求影响显著;同时利用单位根检验指出由于缴纳保费存在分期缴纳的现象,导致保费收入有时间滞后效应。 相似文献
54.
Atomic-Level Regulation of Cobalt Single-Atom Nanozymes: Engineering High-Efficiency Catalase Mimics
Dr. Yuanjun Chen Dr. Bing Jiang Prof. Haigang Hao Dr. Haijing Li Chenyue Qiu Xiao Liang Qingyun Qu Zedong Zhang Prof. Rui Gao Prof. Demin Duan Dr. Shufang Ji Prof. Dingsheng Wang Prof. Minmin Liang 《Angewandte Chemie (International ed. in English)》2023,62(19):e202301879
Nanozymes aim to mimic the highly evolved active centers of natural enzymes. Despite progress in nanozyme engineering, their catalytic performance is much less favorable compared with natural enzymes. This study shows that precise control over the atomic configuration of the active centers of Co single-atom nanozymes (SAzymes) enables the rational regulation of their catalase-like performance guided by theorical calculations. The constructed Co-N3PS SAzyme exhibits an excellent catalase-like activity and kinetics, exceeding the representative controls of Co-based SAzymes with different atomic configurations. Moreover, we developed an ordered structure-oriented coordination design strategy for rationally engineering SAzymes and established a correlation between the structure and enzyme-like performance. This work demonstrates that precise control over the active centers of SAzymes is an efficient strategy to mimic the highly evolved active sites of natural enzymes. 相似文献
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56.
Zhiming Rao Qiaomei Lu Liangzhou Fang Lishuang She Haigang Yan Wenting Chen 《光谱学快报》2013,46(3):249-264
Abstract The effects of three systems on the chemiluminescence (CL) intensity have been studied in this paper, such as leucogen–potassium permanganate–rhodamine B, leucogen–cerium (IV)–rhodamine B, and leucogen–luminol–hydrogen peroxide (called system 1, system 2, and system 3, respectively). The mechanism of these reactions is also discussed. Surfactant (CTMAB) has a remarkably sensitive effect on these systems mentioned above. Therefore, three new flow injection chemiluminescence methods for the determination of leucogen have been established. For system 1, the linear range is 8.0×10?8 to 4.0×10?5 g mL?1, with limits of detection 2×10?8 g mL?1; the relative standard deviation is 2.5% (n=11, Cs=4.0×10?6 g mL?1). For system 2, the linear range is 1.0×10?8 to 5.0×10?6 g mL?1, with limits of detection 3×10?9 g mL?1; the relative standard deviation is 5.1% (n=11, Cs=1.0×10?6 g mL?1). For system 3, the linear range is 4.0×10?8 to 2.0×10?6 g mL?1, with limits of detection 1×10?8 g mL?1; the relative standard deviation is 1.3% (n=11, Cs=1.0×10?7 g mL?1). Compared with the three methods above, system 3 is confirmed as the best method. This method has been applied to the determination of leucogen with satisfactory results. 相似文献
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针对非水平边界条件近似处理所引起的双向声场能量不守恒问题,提出了一种满足能量守恒的双向耦合简正波模型。在模型的建立中,严格考虑了非水平界面的边界条件,并依据介质运动方程和连续性方程推导了便于数值计算的耦合微分方程。同时,结合能量守恒方程和不同海底参数下的数值计算,对模型的准确性进行了研究。由理论分析和仿真结果可以看出,边界条件的严格考虑将导致边界修正项的产生,而边界修正项的引入确保了耦合系数满足对称性和模型所计算的声场满足能量守恒,使得本模型可充分考虑边界水平变化对声场的影响,实现非水平分层波导中双向场的准确计算。 相似文献
59.
In this paper, we establish the existence theorem for the exterior Dirichlet problems for a class of fully nonlinear elliptic equations, which are related to the eigenvalues of the Hessian matrix, with prescribed asymptotic behavior at infinity. This extends the previous results on Monge–Ampère equation and k-Hessian equation to more general cases, in particular, including the special Lagrangian equation. 相似文献
60.