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排序方式: 共有416条查询结果,搜索用时 31 毫秒
31.
32.
Four compounds (TM-1~4) based on N-(4-trifluoromethylphenyl)phenothiazine-S,S-dioxide and N-[3,5-bis(trifluoromethyl)phenyl]phenothiazine-S,S-dioxide are synthesized by Buchwald-Hartwig cross coupling reaction. The effect of different substituents in acceptors on the electronic, photophysical and electrochemical properties are studied by UV–Vis, fluorescence spectroscopy, cyclic voltammetry curves and theoretical calculations. The energy gaps (ΔEST) between singlet excited states (S1) and triplet excited states (T1) of these compounds decrease by addition of one para-substituted CF3 or two meta-substituted CF3 on N-phenyl in order to enhance the electron-withdrawing capability of the acceptors. Small ΔEST of these compounds range from 0.09 eV to 0.18 eV. TM-2~4 exhibit thermally activated delayed fluorescence (TADF) characteristics with short delayed fluorescence lifetimes (τd) within 0.69-1.16 μs. TM-3 emits blue light with an emission wavelength of 475 nm. 相似文献
33.
In this paper, we study the existence and multiplicity of positive solutions for the system of the generalized Lidstone problems We use fixed point index theory to establish our main results based on a priori estimates achieved by utilizing some properties of concave functions, so that the nonlinearities f and g are allowed to grow in distinct manners, with one of them growing superlinearly and the other growing sublinearly. 相似文献
34.
N.?A.?SkoptsovEmail author I.?A.?Denisov A.?M.?Malyarevich K.?V.?Yumashev O.?S.?Dymshits A.?A.?Zhilin I.?P.?Alekseeva 《Journal of Applied Spectroscopy》2011,78(5):650-658
Luminescence regularities have been studied in new erbium/ytterbium materials based on glasses and glass ceramics of a magnesium-aluminosilicate
system containing nanoscale erbium/ytterbium zirconate titanate crystals with the pyrochlore structure. Lifetimes of Yb3+ and Er3+ ions in the 2 F5/2 state and in the 4I11/2 and 4I13/2 states, respectively, and the efficiency of Yb3+ → Er3+ energy transfer have been evaluated. The identified spectral-luminescent characteristics of the studied glasses and glass
ceramics co-doped with erbium and ytterbium ions show that these materials are promising media for producing laser generation
in the spectral range around 1.5 μm. 相似文献
35.
Zhilin Xia 《Optics Communications》2011,284(6):1637-1641
A physical model of the laser induced electron transport in dielectric with small size is discussed. The model assumes that free electrons are originally existent or produced by impact detrapping. The free electrons transporting in low dimensional dielectrics interact with phonons and surface. When the laser electric field strength is high enough, the inelastic electron scattering such as impact ionization and cascade processes will play important roles. A small size effect has been found in electron absorbing laser energy under the conditions that the laser wavelength is in near infrared zone and the material has size in nanometer level. This is a very significative effect to enlighten us on preparing ultrahigh threshold laser films with new nano-structure. 相似文献
36.
以BBOT为电子传输层的聚合物蓝色发光二极管 总被引:7,自引:0,他引:7
在前篇文章中[1]我们报导了以perylene掺杂的PVCz聚合物单层电致发光器件,得到蓝色发光,其亮度为59(cd/m2).在这篇文章中,我们以PVCz作为空穴传导层,BBOT为电子传导层制成了双层结构的发光二极管.亮度和效率都大大超过单层器件. 相似文献
37.
本文利用桥式平衡电路及Sawyer-Towre电路系统地测量了薄膜电致发光(TFEL)器件的损耗电流波形,发光亮度波形及电荷电压回线.在实验基础上建立了TFEL电子传输过程的物理模型和等效电路,由克希霍夫定律可建立激活层的瞬态电压及电流的微分方程,由此导出损耗电流波形,发光亮度波形及Q-V回线的数学表达式.利用计算机模拟将计算结果与实验进行比较,利用四个调节参数即得到与实验相当好的拟合. 相似文献
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Some new sixth-order compact finite difference schemes for Poisson/Helmholtz equations on rectangular domains in both two- and three-dimensions are
developed and analyzed. Different from a few sixth-order compact finite difference
schemes in the literature, the finite difference and weight coefficients of the new
methods have analytic simple expressions. One of the new ideas is to use a weighted
combination of the source term at staggered grid points which is important for grid
points near the boundary and avoids partial derivatives of the source term. Furthermore, the new compact schemes are exact for 2D and 3D Poisson equations if the
solution is a polynomial less than or equal to 6. The coefficient matrices of the new
schemes are $M$-matrices for Helmholtz equations with wave number $K≤0,$ which
guarantee the discrete maximum principle and lead to the convergence of the new
sixth-order compact schemes. Numerical examples in both 2D and 3D are presented
to verify the effectiveness of the proposed schemes. 相似文献