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171.
Asymptotic solution of a weak nonlinear model for the mid-latitude stationary wind field of a two-layer barotropic ocean 下载免费PDF全文
A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the corresponding problem is discussed. 相似文献
172.
Simulation of electron cyclotron current drive and electron cyclotron resonant heating for the HL-2A tokamak* 下载免费PDF全文
A quasi-linear formalism is developed for relativistic particles. It is self-consistent including spatial diffusion. An attempt is made to simulate the process of electron cyclotron resonant heating (ECRH) and electron cyclotron current drive (ECCD) for the HL-2A tokamak. Temperature oscillating regimes in Tore Supra diagnosed by MHD activity seem to be reproduced in the simulation. The special feature in this paper is to see the resonance in the long time scale for relativistic plasma. 相似文献
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Influence of ITO,Graphene Thickness and Electrodes Buried Depth on LED Thermal-Electrical Characteristics Using Numerical Simulation 下载免费PDF全文
Finite elements methods are used to investigate the thermal-electrical characteristics of gallium-nitride (GaN) light-emitting diodes (LEDs) with different transparent conductive layers (TCLs) and buried depths of electrodes, where the transparent conductive layers include indium tin oxide (ITO), graphene (Gr) and the combination of them (ITO/Gr). The optimal material parameters and the precision and accuracy of the simulation model are validated. Moreover, the parameters' sensitivity analysis is carried out as well. The results indicate that the LED with the TCL of a lO0-nm ITO or 4-1ayer Gr has a good thermal-electrical performance from the viewpoint of the maximum temperature and the current density deviation of multiple quantum well (MQW), where the maximum temperature occurs at the n-Pad rather than p-Pad. The compound TCL with a 20-nm ITO and 3- layer Gr reaches a thermal-electrical performance better than that of a lO0-nm ITO or 4-layer Gr. Moreover, their maximum temperatures decrease about -0.43% and 1.21%, and the current density uniformities increase up to -6.09% and 17.41%, respectively. Furthermore, when the electrode buried depth is 0.51 μm, the thermal-electrical performance of the GaN LEDs can be further improved. 相似文献
176.
Yang Li-Ping Wang Li-Yuan Wang Jia-Qi Zare Ali Brown Richard J. 《Nonlinear dynamics》2021,103(3):2241-2256
Nonlinear Dynamics - The Hopf bifurcation behavior is an important issue for the nonlinear dynamic analysis of gas foil bearing (GFB)-rotor systems. However, there is a lack of detailed study on... 相似文献
177.
高约束模式(H模)下自发产生的边缘局域模(ELM),虽然利于控制等离子体密度和排出杂质粒子从而实现H模放电的稳态运行,但是ELM爆发携带的大量粒子和能量会对装置的第一壁材料造成很大的损坏,所以在下一代聚变装置上使用之前很多装置已经开始了对ELM的研究.在HL-2A装置上观察到了不同的ELM,扰动幅度小的ELM引起的等离子体储能损失小于3%,ELM之间的时间间隔约为3 ms,表现出Ⅲ型ELM的特征;扰动幅度较大的ELM的爆发对等离子体电流、等离子体密度及储能都有很明显的扰动,对等离子体储能的扰动大于10%,ELM爆发的频率随通过等离子体磁分界面的净加热功率的增加而增加,表现出明显的Ⅰ型ELM的特征.ELM先兆有不对称性,在弱场侧磁探针信号能观测到,但强场侧却观测不到;ELM先兆的频率约为45 kHz,观测到的最长的先兆先于ELM前约10ms出现. 相似文献
178.
Jia-Qi Wu Xin-Yuan Wu Dr. Jian-Mei Lu Prof. Dr. Qian Shi Dr. Li-Xiong Shao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(69):e202202441
In this study, a novel La(III)-based two-dimensional (2D) metal-organic framework, [La2/3(qptca)1/2] (referred to as SLX-2), from LaCl3 and 1,1′ : 4′,1′′ : 4′′,1′′′ : 4′′′,1′′′′-quinquephenyl]-2,2′′,2′′′′,5′′-tetracarboxylic acid (H4qptca) was synthesized by conventional solvothermal method and thoroughly characterized by using X-ray single-crystal diffraction, powder X-ray diffraction, and thermogravimetric analyses. The 2D SLX-2 features a unique lanthanum center exposed to the skeleton and was used as an efficient Lewis acid catalyst for the Friedel-Crafts alkylation of indole and pyrrole with β-nitrostyrene along with a wide substrate scope, giving the desired products in good-to-high yields under the optimal reaction conditions. Furthermore, the catalyst was used for twenty cycles, with nearly no effect on its activity, and the reaction was heterogeneous in nature. Moreover, compared to the previous hydrogen-bond-donating MOF catalysts for such alkylation reactions, SLX-2 showed an excellent stability toward harsh acidic and basic environment, and gave comparable catalytic activities. 相似文献
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借助溶胶-凝胶结合相分离和模板法进行了阶层多孔结构的搭建及二氧化硅多孔块体材料的制备,表征了阶层多孔块体的显微结构及孔结构特性,分析了阶层多孔结构的搭建机理。研究结果表明,三嵌段共聚物聚环氧乙烷-聚环氧丙烷-聚环氧乙烷(P123)的加入不仅诱导共混体系发生相分离,调控大孔结构的形成,同时形成球形胶束并作为模板剂进入骨架,而1,3,5-三甲基苯(TMB)的加入使P123形成的胶束膨胀且更加稳定,在骨架上成功引入了球形介孔,骨架中凝胶粒子相互聚集形成微孔,从而搭建贯通大孔-球形介孔-微孔同时分布的阶层多孔结构,并获得相应的多孔块体材料;当正硅酸甲酯(TMOS):P123:TMB摩尔比为1:0.015:0.353时,多孔块体材料的阶层多孔结构最优,大孔孔径为0.5-1.5 μm,介孔孔径为3-4 nm,显气孔率66.1%,比表面积为616 m2·g-1。 相似文献