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991.
空穴传输基团修饰的吡嗪铱配合物的合成及其发光性质 总被引:1,自引:0,他引:1
设计合成了空穴传输性咔唑基团修饰的吡嗪配体, 2,3-二(4-(9-咔唑基甲基)苯基)-5-甲基吡嗪(CzMPMP)及其铱配合物Ir(CzMPMP)2(acac)(acac: 乙酰丙酮). 用核磁共振(NMR)、质谱、元素分析等方法对其进行了表征, 并用紫外-可见吸收光谱、液相和固相光致发光光谱对其光学性质进行了研究. 通过与没有咔唑取代基的2,3-二苯基-5-甲基吡嗪铱配合物Ir(DPMP)2(acac)进行对照, 说明咔唑基团对配合物的光学性质有显著影响. 不含咔唑取代基的配合物Ir(DPMP)2(acac)的固态光致发光光谱中存在很强的激活双体(excimer)峰, 而Ir(CzMPMP)2(acac)的固态光致发光光谱中未发现有激活双体峰; 并且在溶液中, 含有咔唑取代基的配合物Ir(CzMPMP)2(acac)较Ir(DPMP)2(acac)的光致发光强度有显著提高. 这些结果说明咔唑基团的空间位阻可以有效阻止配合物成膜时产生激活双体, 从而消除发射峰红移现象并提高发光效率. 相似文献
992.
For a set A of nonnegative integers, the representation functions R2(A,n) and R3(A,n) are defined as the numbers of solutions to the equation n = a + a′ with a,a′∈ A, a < a′ and a a′, respectively. Let N be the set of nonnegative integers. Given n0 > 0, it is known that there exist A,A′■ N such that R2(A′,n) = R2(N \ A′,n) and R3(A,n) = R3(N \ A,n) for all n n0. We obtain several related results. For example, we prove that: If A ■ N such that R3(A,n) = R3(N \ A,n) for all n n0, then (1) for any n n0 we have... 相似文献
993.
FAN CuiLing LEI JianGuo & SHAN XiuLing School of Sciences Nantong University Nantong China College of Mathematics Information Science Hebei Normal University Shijiazhuang 《中国科学 数学(英文版)》2011,(1)
Difference systems of sets (DSSs) are combinatorial configurations which were introduced in 1971 by Levenstein for the construction of codes for synchronization. In this paper, we present two kinds of constructions of difference systems of sets by using disjoint difference families and a special type of difference sets, respectively. As a consequence, new infinite classes of optimal DSSs are obtained. 相似文献
994.
ZHANG Mei School of Mathematical Sciences Beijing Normal University Beijing China 《中国科学 数学(英文版)》2011,(2)
In this paper, we study the count of head runs up to a fixed time in a two-state stationary Markov chain. We prove that in total variance distance, the negative binomial, Poisson and binomial distributions are appropriate approximations according to the relation of the variance and mean of the count, generalizing earlier results in previous literatures. The proof is based on Stein’s method and coupling. 相似文献
995.
LI JunPing & LIU ZaiMing School of Mathematical Science Computing Technology Central South University Changsha China 《中国科学 数学(英文版)》2011,(5)
We consider a modified Markov branching process incorporating with both state-independent immigration-migration and resurrection. The effect of state-independent immigration-migration is firstly in- vestigated in detail. The explicit expressions for the extinction probabilities and mean extinction times are presented. The ergodicity and stability properties of the process incorporating with resurrection structure are then investigated. The conditions for recurrence, ergodicity and exponential ergodicity are... 相似文献
996.
CHEN Meng School of Mathematical Sciences & LMNS Fudan University Shanghai China 《中国科学 数学(英文版)》2011,(8)
We investigate birationality of the anti-pluricanonical map Φ-m,the rational map defined by the anti-pluricanonical system |-mKX|,on weak Q-Fano 3-folds. 相似文献
997.
YE Liu HU GuiYu & LI AiXia School of Physics & Material Science Anhui University Hefei China 《中国科学:物理学 力学 天文学(英文版)》2011,(1)
We propose a unified scheme to implement the optimal 1→ 3economical phase-covariant quantum cloning and optimal 1→3 economical real state cloning with superconducting quantum interference devices (SQUIDs) in a cavity.During this process,no transfer of quantum information between the SQUIDs and cavity is required.The cavity field is only virtually excited.The scheme is insensitive to cavity decay.Therefore,the scheme can be experimentally realized in the range of current cavity QED techniques. 相似文献
998.
WU HaiTao LU XiaoChun ZOU DeCai & HAN Tao National Time Service Center Chinese Academy of Sciences Xi'an China Key Laboratory of Precision Navigation Timing Technology 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
Navigation augmentation technology is one of the most common methods to increase the continuity,reliability and integrity of the global satellite navigation system.The concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this paper.The study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing information.The neural cell model of Voluntee... 相似文献
999.
ZHOU ShanShi HU XiaoGong WU Bin LIU Li QU WeiJing GUO Rui HE Feng CAO YueLing Wu XiaoLi ZHU LingFeng SHI Xin & TAN HongLi Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai China Graduate University of Chinese Academy of Sciences Beijing Beijing Global Information Application Development Center Beijing 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
Aiming at regional services,the space segment of COMPASS (Phase I) satellite navigation system is a constellation of Geostationary Earth Orbit (GEO),Inclined Geostationary Earth Orbit (IGSO) and Medium Earth Orbit (MEO) satellites.Precise orbit determination (POD) for the satellites is limited by the geographic distribution of regional tracking stations.Independent time synchronization (TS) system is developed to supplement the regional tracking network,and satellite clock errors and orbit data may be obtai... 相似文献
1000.
YANG YuJuan & YAN Biao School of Materials Science Engineering Tongji University Shanghai China Shanghai Key Lab of Development Application for Metal Functional Materials 《中国科学:物理学 力学 天文学(英文版)》2011,(5)
With the multi-phase field model, the unidirectional solidification with constant velocity growth and variable velocity growth of the CBr4-C2Cl6 eutectic alloy is simulated in three dimensions. The simulated results with constant velocity growth show that with the increase of pulling velocity, the morphology of the CBr4-C2Cl6 alloy evolves in the sequence of lamellar merging →lamellar-rod transition→stable lamellar growth→oscillating growth→lamellar branching. A morphology selection map is established with ... 相似文献