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排序方式: 共有613条查询结果,搜索用时 234 毫秒
71.
Lin‐Jian Zhu Jian Wang Tie‐Gang Reng Chun‐Yan Li Dong‐Cai Guo Can‐Cheng Guo 《Journal of Physical Organic Chemistry》2010,23(3):190-194
Six tetraphenylporphyrins (TRPPH2) with different horizontal substituents R (R = H, CH3, OH, F, Cl, Br) were synthesized, and the organic light‐emitting diode (OLED) devices with a general configuration of ITO/TPD/Alq3:2%TRPPH2/Alq3/Al were prepared. The substituted TRPPH2 was used as the host dopant, 4,4‐bis‐(m‐tolyphenylamino)biphenyl (TPD) was used as a hole‐transporting material, and aluminum tris(8‐quinolinolato) (Alq3) was used as an electron‐transporting material. The electroluminescent (EL) properties of these devices were studied to understand the light emitting properties of the substituted TRPPH2. Previous studies have found that the color emitted by the devices was dependent on the TRPPH2 dye concentration. The electronic effect of the horizontal substituents R of TRPPH2 influenced the turn‐on voltage, brightness, and power efficiency of the devices. Also, the electroluminescence performance of the porphyrin‐doped OLED devices depended on the effectual overlaps between the emission of electron‐transporting material and the absorption of the dopants. This means that it is possible to evaluate the electroluminescence performance of the porphyrin‐doped OLED devices based on the emission of electron‐transporting material and the absorption of the dopants. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
72.
Fan L Song H Zhao H Pan G Yu H Bai X Li S Lei Y Dai Q Qin R Wang T Dong B Zheng Z Ren X 《The journal of physical chemistry. B》2006,110(26):12948-12953
An inorganic-organic hybrid semiconductor, ZnS/CHA (CHA = cyclohexylamine) nanocomposites was successfully synthesized via a solvothermal method using CHA as solvent, which yielded uniform and ultralong nanowires with widths of 100-1000 nm and lengths of 5-20 microm. Changing the reaction conditions could alter the morphology and optical properties of the nanocomposites. The periodic layer subnanometer structures were identified by high-resolution transmission electron microscopy (HR-TEM) images, with thickness of approximately 2 nm. The composites exhibited a very large blue-shift in their optical absorption edge as well as an exciton excitation band due to a strong quantum confinement effect caused by the internal subnanometer-scale structures. The pure hexagonal wurtzite ZnS nanowires were also obtained by extracting the ZnS/CHA nanocomposites with dimethyl formamide (DMF). In addition, the luminescent properties of exciton and defect-related transitions in different samples of ZnS/CHA were discussed in detail. 相似文献
73.
利用BMS1势能面[Brandao等,J.Chem.Phys.121,8861(2004)],选取碰撞能为34.6 kcal/mol,用准经典轨线方法研究了O(3P)+H2反应的立体动力学性质.计算并讨论了k与j'的夹角的分布关系P(θr)以及描述k-k'-j'三者关系的二面角分布P((ρ)r).(k)为反应物速度方向,k'为产物的速度方向,j'为产物的角动量方向)P(θr)的峰值在90°附近并且关于90°呈对称性分布,这表明产物角动量的方向与初速度的方向垂直.二面角分布P((ρ)r)关于散射平面呈反对称性分布,这一结果表明产物的角动量具有强烈的极化效应.另外,我们还研究了振动激发对产物角动量的影响,结果表明产物的矢量性质对反应物的初始振动态非常敏感. 相似文献
74.
We consider the original discontinuous Galerkin method for the first-order hyperbolic problems in d-dimensional space. We show that, when the method uses polynomials of degree k, the L2-error estimate is of order k+1 provided the triangulation is made of rectangular elements satisfying certain conditions. Further, we show the O(h2k+1)-order superconvergence for the error on average on some suitably chosen subdomains (including the whole domain) and their outflow faces. Moreover, we also establish a derivative recovery formula for the approximation of the convection directional derivative which is superconvergent with order k+1. 相似文献
75.
There recently has been much interest in studying optimization problems over symmetric cones. In this paper, we first investigate
a smoothing function in the context of symmetric cones and show that it is coercive under suitable assumptions. We then extend
two generic frameworks of smoothing algorithms to solve the complementarity problems over symmetric cones, and prove the proposed
algorithms are globally convergent under suitable assumptions. We also give a specific smoothing Newton algorithm which is
globally and locally quadratically convergent under suitable assumptions. The theory of Euclidean Jordan algebras is a basic
tool which is extensively used in our analysis. Preliminary numerical results for second-order cone complementarity problems
are reported. 相似文献
76.
A necessary and sufficient condition is obtained for the incompleteness of complex exponential system in the weighted Banach space Lαp = {f:∫+∞∞ |f(t)e-α(t)|pdt +∞},where 1 ≤ p +∞ and α(t) is a weight on R. 相似文献
77.
Tie Ni 《Applied mathematics and computation》2010,216(7):2207-3378
The smoothing-type algorithm has been successfully applied to solve various optimization problems. In general, the smoothing-type algorithm is designed based on some monotone line search. However, in order to achieve better numerical results, the non-monotone line search technique has been used in the numerical computations of some smoothing-type algorithms. In this paper, we propose a smoothing-type algorithm for solving the nonlinear complementarity problem with a non-monotone line search. We show that the proposed algorithm is globally and locally superlinearly convergent under suitable assumptions. The preliminary numerical results are also reported. 相似文献
78.
We study the sub‐Riemannian geometry on the Engel group which is a step 3 nilpotent Lie group on . Our main result is to solve the Hamiltonian equations associated with the bi‐characteristic curves and express the solutions in terms of elliptic functions. Our model covers both the Heisenberg group and the Martinet case when setting certain parameters to be zero. 相似文献
79.
In this paper, based on some known fourth-order Steffensen type methods, we present a family of three-step seventh-order Steffensen type iterative methods for solving nonlinear equations and nonlinear systems. For nonlinear systems, a development of the inverse first-order divided difference operator for multivariable function is applied to prove the order of convergence of the new methods. Numerical experiments with comparison to some existing methods are provided to support the underlying theory. 相似文献
80.
Cong Liu Lirong Zheng Qian Song Zhenjie Xue Chuanhui Huang Lu Liu Xuezhi Qiao Xiao Li Keyan Liu Tie Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(7):2077-2081
A simple method was adopted in which ultrathin cerium oxide nanoplates (<1.4 nm) were synthesized to increase the surface atomic content, allowing transformation from a face‐centered cubic (fcc) phase to a body‐centered tetragonal (bct) phase. Three types of cerium oxide nanoparticles of different thicknesses (1.2 nm ultrathin nanoplates, 2.2 nm nanoplates, and 5.4 nm nanocubes) were examined using transmission electron microscopy and X‐ray diffraction. The metastable bct phase was observed only in ultrathin nanoplates. Thermodynamic energy analysis confirmed that the surface energy of the ultrathin nanoplates is the cause of the remarkable stabilization of the metastable bct phase. The mechanism of surface energy regulation can be expanded to other metallic oxides, thus providing a new means for manipulating and stabilizing novel materials under ambient conditions that otherwise would not be recovered. 相似文献