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Search Results: 1 - 10 of 85043 matches for " LANG Jun-wei "
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兼具高质量和高体积能量密度的水系全金属氧化物不对称超级电容器
An Aqueous All-Metal Oxide Asymmetric Supercapacitor with High Gravimetric and Volumetric Energy Densities

荆 鑫,张 旭,王 玮,郎俊伟
JING Xin
, ZHANG Xu, WANG Wei, LANG Jun-wei

- , 2018, DOI: 10.13208/j.electrochem.180204
Abstract: 摘要 超级电容器只有兼具高质量和高体积能量密度才能拥有更广泛的应用价值.本文采用具有纳米结构及高填充密度的RuO2(纳米球,1.69 g·cm-3)和Co-Ni氧化物(纳米片,2.14 g·cm-3)分别作为负极和正极材料,成功地构筑了RuO2 // KOH / / Co-Ni氧化物非对称超级电容器.所得不对称超级电容器具有高电压窗口(0~1.5V)、高质量比容量(217.5 F·g-1)和高体积比容量(412.3 F·cm-3)、高质量能量密度(61.8 Wh·kg-1)和高体积能量密度(121 Wh·L-1)的优良性能,在1.4V的电压下以2 A·g-1的电流密度历经5000次循环后比容量保持率为87%.
Only with both high gravimetric and high volumetric energy densities, can supercapacitors find more extensive applications.In this paper, by making good use of the interesting nanostructures and the high packing densities of RuO2 (nanoshpheres,1.69 g·cm-3) and Co-Ni oxide (nanoflakes, 2.14 g·cm-3), the RuO2//KOH//Co-Ni oxide all-metal oxide asymmetric supercapacitors with high performance were successfully fabricated, which led to the maximum specific capacitance of 217.5 F·g-1 (412.3 F·cm-3) and specific energy density of 61.8 Wh·kg-1 (121 Wh·L-1) in a cell voltage between 0 and 1.5 V in KOH electrolyte. In addition, the constructed supercapacitor device could retain 87% of the initial specific capacitance even at 5000th cycle with the cell voltage of 1.4 V at a current density of 2 A·g-1 in life cycle test, indicating high electrochemical stability
超级电容器能量密度的提升策略
Strategies to Enhance Energy Density for Supercapacitors

郎俊伟,张旭,王儒涛,阎兴斌
LANG Jun-wei
, ZHANG Xu, WANG Ru-tao, YAN Xing-bin

- , 2017, DOI: 10.13208/j.electrochem.170348
Abstract: 摘要 超级电容器最大的优点是具有优良的脉冲充放电性能和快速充放电性能,同时具有循环寿命长、工作温度范围宽、安全无污染等特性,但能量密度较低. 本文对超级电容器的工作原理、发展状况、缺陷所在和改进方法进行了简要介绍,以本课题组在高比能超级电容器方面的研究工作为主线,结合近几年的文献报道,重点阐述了超级电容器能量密度的提升策略. 主要围绕以下三个方面开展了工作:1)通过将电极材料尺寸纳米化来提高传统电极材料的比容量或开发其他高比容量的电极材料;2)发展具有高电压窗口的离子液体电解液,或利用不同材料在不同电位区间的电容特性构筑不对称电容器,从而提高超级电容器的电压窗口;3)将超级电容器和锂离子电池进行“内部交叉”构筑兼具高能量密度和高功率密度的锂离子混合电容器. 最后,对超级电容器的发展进行了展望
Dimerization of 1-Phenyl-1H-Tetrazole-5-Thiol over Metalloporphyrin Catalysts  [PDF]
Ya-hong Wu, Jun-wei Yang, Yan Yan, Shan-ling Tong, Di Tan, Jian Yu, Lin Yu
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.23047
Abstract: In an alkaline methanol solution, dimerization of 1-phenyl-1H-tetrazole-5-thiol (HL) was carried out over metalloporphyrin catalysts under mild conditions. The dimer product, 1,2-bis (1-phenyl-1H-tetrazol-5-yl) disulfane (L-L), was characterized by determinations of infrared (IR), HPLC, NMR and elementary analysis respectively. In situ UV-Vis spectroscopic analysis and cyclic voltammetric (CV) determinations suggested that the active intermediate for L-L formation is an axially ligated complex, RS-MnTHPP, which decomposes into a MnTHPP molecule and a stable radical (SR) for coupling to form the disulfane. Meanwhile MnIITHPP molecule can be oxidized easily to form MnTHPP species again by oxygen from the air for using in next catalytic circle.
Conservation laws of some lattice equations
Jun-wei Cheng,Da-jun Zhang
Physics , 2012, DOI: 10.1007/s11464-013-0304-z
Abstract: We derive infinitely many conservation laws for some multi-dimensionally consistent lattice equations from their Lax pairs. These lattice equations are the Nijhoff-Quispel-Capel equation, lattice Boussinesq equation, lattice nonlinear Schr\"{o}dinger equation, modified lattice Boussinesq equation, Hietarinta's Boussinesq-type equations, Schwarzian lattice Boussinesq equation and Toda-modified lattice Boussinesq equation.
A New Scheme to Projective Synchronization of Fractional-Order Chaotic Systems

WANG Jun-Wei,CHEN Ai-Min,

中国物理快报 , 2010,
Abstract:
The green revolution in China-A review of the Cybernetics Ecosystem Engineering
中 国 的 绿 色 革 命——试论生态控制系统工程学

Guan Jun-wei,
关君蔚

中国生态农业学报 , 1996,
Abstract: 本文结合我国防护林体系建设取得的重大成就,概要论述了生态控制系统工程学的理论与实践,指出生物科学研究从微观上是探索生命的奥秘,从宏观上是研究如何控制和利用生态系统;并阐明了该系统相应的“黑箱结构”、“瞬时模式”、“生物生产单元”之间的机理以及进一步把我国防护林体系建设引向现代科学轨迹的现实意义和影响。
A new mammalian circadian oscillator model including the Camp module

Wang Jun-Wei,Zhou Tian-Shou,

中国物理 B , 2009,
Abstract:
The Research of the Measures Algorithm of the Parameter of the Cutter
S. Ya-ceng,C. Jing,T. Jun-wei
International Journal of Image, Graphics and Signal Processing , 2011,
Abstract: Edge detection is the most basic problem in the process of image processing. The precision of traditional edge detection algorithm is not very high, it unable to meet the high precision need of modern industrial test technology. In order to overcome the deficiency, this text proposed subpixel edge detection algorithm based on the function curve fitting-Gauss fitting of gradient direction sub-pixel edge detection algorithm. According to the gradient distribution of the image, this text use gauss curve fitting the edge in order to realize the sub-pixel location. This text compared this algorithm with sub-pixel edge detection based on the LOG operator and sub-pixel edge detection based on the quadratic, and draw that this algorithm not only have the short running time and high efficiency, but also has proved that the algorithm has rotation invariant through the experiment. It is that pattern recognition and picture measure the important pretreatment means in the course to follow the method at the border, contradiction at accuracy and speed that but follow the method and exist at the traditional border. To above-mentioned problems, this text proposes following algorithms at the border based on model, and then try to get the diameter of the cutter. The experiment shows this algorithm at the realization border that can be very good and follows, measure the comparison of the algorithm through two kinds of diameters, drawing the running time of least square method shorter, efficiency is relatively high.
Robust Control for a Class of Nonlinear Distributed Parameter Systems via Proportional-Spatial Derivative Control Approach
Cheng-Dong Yang,Jianlong Qiu,Jun-Wei Wang
Abstract and Applied Analysis , 2014, DOI: 10.1155/2014/631071
Abstract: This paper addresses the problem of robust control design via the proportional-spatial derivative (P-sD) control approach for a class of nonlinear distributed parameter systems modeled by semilinear parabolic partial differential equations (PDEs). By using the Lyapunov direct method and the technique of integration by parts, a simple linear matrix inequality (LMI) based design method of the robust P-sD controller is developed such that the closed-loop PDE system is exponentially stable with a given decay rate and a prescribed performance of disturbance attenuation. Moreover, a suboptimal controller is proposed to minimize the attenuation level for a given decay rate. The proposed method is successfully employed to address the control problem of the FitzHugh-Nagumo (FHN) equation, and the achieved simulation results show its effectiveness. 1. Introduction A significant research area that has received a lot of attention over the past few decades is the control design for distributed parameter systems (DPSs) modeled by parabolic partial differential equations (PDEs). These DPSs can be applied to describe many industrial processes, such as thermal diffusion processes, fluid, and heat exchangers [1–4]. The key characteristic of DPSs is space distribution, which causes their outputs, inputs, process states, and parameters to be spatially varying. On the other hand, external disturbances and nonlinear phenomena appear in most real systems. In this situation, the study of robust control design for nonlinear parabolic PDE systems is of theoretical and practical importance. Significant research results have been reported in the past few decades for DPSs [1–3, 5–18]. The most interesting results within these research activities are those developed on the basis of PDE model [9–18]. For example, Krstic and Smyshlyaev have developed nonadaptive and adaptive kernel-based backstepping methods for linear boundary control PDE systems [9–11]. Fridman and Orlov [12] have presented exponential stabilization with performance in terms of linear matrix inequalities (LMIs) for uncertain semilinear parabolic and hyperbolic systems via a robust collocated static output feedback boundary controller. These results [9–12] are only applicable for boundary control PDE systems. Motivated by significant recent advances in actuation and sensing technology, particularly the advances of microelectromechanical systems, it is possible to manufacture large arrays of microsensors and actuators with integrated control circuitry (for control applications of such devices, see [13] and the
Supercoupling between heavy-hole and light-hole states in self-assembled quantum dots
Jun-Wei Luo,Gabriel Bester,Alex Zunger
Physics , 2014, DOI: 10.1103/PhysRevB.92.165301
Abstract: Spintronics, quantum computing and quantum communication science utilizing cubic semiconductors rely largely on the properties of the hole states, composed of light and heavy hole wavefunction components. The admixture of light-hole (LH) into ground hole state predominately by the heavy hole (HH) would induce unique features of LH in optical transitions, spin relaxation, and spin polarization. We point to an unexpected source of HH-LH mixing in quantum dots, arguing that in contrast with current models the mixing does not reflect the strain between the dot and its matrix and does not scale inversely with the energy splitting between the bulk HH and LH states. Instead, we show via atomistic pseudopotential calculations on a range of strained and unstrained dots of different symmetries that the HH-LH mixing is enabled by the presence in the QD of a dense ladder of intermediate states between the HH and LH states which amplifies and propagates this interaction and leads to "supercoupling" (analogous to super-exchange in magnetism). This explains a number of outstanding puzzles regarding the surprising large coupling seen in unstrained QD (GaAs/AlAs) of ideal shapes and the surprising fact that in strained QD (InAs/GaAs) the coupling is very strong despite the fact that the 12-fold increase in bulk HH-LH splitting overrides the ~4 fold enhancement of the coupling matrix element by strain in comparison with unstrained GaAs QDs.
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