Dendron-functionalized perylene diimides with carrier-transporting ability for red luminescent materials

This paper presents a series of dendrimers via a convergent synthetic approach with three generations, which contain perylene diimide cores, Fréchet-type poly(aryl ether) dendrons, and carbazole (CZ) or oxadiazole (OXZ) peripheral functional groups. The higher generation dendrimer has an obvious site-isolation or dilution effect of dendrons, which results in a relatively small red-shift of absorption and emission spectra when it forms a solid thin film for applications. The interactions between peripheral units and perylene diimide core in the dendrimers are also studied by steady-state and time-resolved fluorescence spectra under both direct and indirect excitation. The fluorescence data show that there exist two possible mechanisms, Förster energy transfer (FRET) and photo-induced electron transfer (PET), for dendrimers bearing carbazole units. No enhanced core fluorescence is observed because the energy transfer or light-harvesting potential of peripheral carbazole is counteracted by PET. While for dendrimers bearing oxadiazole units, no PET can take place between OXZ and perylene diimide since both of them are high electron affinity. The FRET and higher light-harvesting ability of oxadiazole without PET interfering result in the distinct enhancement of core emission in higher generation dendrimers. DSC results indicate that the incorporation of Fréchet-type poly(aryl ether) dendrons can improve the amorphous property and increase glass transition temperature (T_g). The preliminary EL results with single-layer architectures demonstrate that these dendrimers could be utilized as a promising kind of active red luminescent emitters with carrier-transporting ability. EL emission has the same recombination zone as PL, indicating that the recombination of excitons in fabricated EL devices is not close to cathode or anode vicinity. It is suggested that the site-isolation effect of dendron wedges is attributed to prevent the core luminorphores from approaching electrodes efficiently.     

辊道窑烧嘴喷射角度对窑内湍流气流影响的研究

应用k -ε两方程湍流模型 ,对辊道窑烧成带的湍流旋流流动进行了理论分析 ,并用计算流体力学软件Fluent进行数值模拟 ,研究了烧嘴的喷射角度对烧成带内的湍流旋流流动的影响及其对制品烧成的作用     

Effects of the solvent polarity on the atom transfer radical polymerization of methyl methacrylate initiated by 4‐(chloromethyl)phenyltrimethoxysilane

The controllability of the atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N‐dimethylformamide and the nonpolar solvent xylene with 4‐(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′‐bipyridine and CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as catalyst systems was studied. Gel permeation chromatography analysis established that in the nonpolar solvent xylene, much better control of the molecular weight and polydispersity of poly(methyl methacrylate) was achieved with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system than with the CuCl/2,2′‐bipyridine as catalyst system. In the polar solvent N,N‐dimethylformamide, unlike in xylene, the polymerization was more controllable with the CuCl/2,2′‐bipyridine catalyst system than with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2751–2754, 2007     

PTA装置改造中的技术探讨

概述了天津石化公司 2 50 kt/ a PTA装置一期 4个系统和空压机等方面的改造 ,对进一步改造将遇到的空压机系统、氧化反应器及其顶部冷凝系统、醋酸脱水塔系统、加氢预热系统、干燥机系统的有关问题进行了探讨 ,并提出进行设备极限能力标定、在操作时间上挖潜及进一步优化二期改造方案的若干建议。     

焊接工艺规程管理系统──计算机在焊接中的应用

介绍了用于编制焊接工艺规程的管理系统。该系统的特点是方便适用，应用范围广泛。     

集成电路密封用高纯邻甲酚醛环氧树脂的制备

ECN树脂中的可水解氯含量是决定树脂质量的—个重要指标。本文研究了反应温度、ECH/OCN配比、反应时间和碱用量等因素的影响,取得了规律性的认识,并获得最佳配方,制备出高纯度的ECN树脂系列产品。     

A New Robust Adaptive Control of Uncertain Nonlinear Systems and Pendulum Application

A new robust adaptive control of uncertain nonlinear systems is proposed in this paper. The proposed method combines sliding mode control with the immersion and invariance (I&I) adaptive scheme, and it has more available degrees of freedom than using the backstepping scheme. Via the proposed method, a class of nonlinear systems with mismatched parametric perturbations can be rendered asymptotically stable and the performance of the system can also be improved. Finally, the proposed method is applied to a simple pendulum with motor dynamics, and simulation results show the effectiveness and performance of the proposed method.     

Quantum identity authentication based on ping-pong technique without entanglements

A quantum identity authentication scheme based on ping-pong technique without entanglements is proposed. It can verify the legitimate user’s identity and update the initial authentication key for reuse. The security of the proposed scheme is extensively analyzed and accordingly confirmed in the case of general individual attacks. The present scheme owns high efficiency due to the use of single-particle states in a two-way quantum channel. Moreover, the scheme is economical and feasible with present-day technique.     

Stochastic reliable control of a class of networked control systems with actuator faults and input saturation

The stochastic reliable control problem for networked control systems (NCSs) subject to actuator failure and input saturation is investigated in this paper. In order to get the relationship between the maximum allowable consecutive packet dropouts, the packet dropout probability, the actuator failure matrix and the input saturation, a packet dropout probability dependent condition is given via linear matrix inequality (LMI) technology. Then, a suitable reliable controller is designed to ensure the closed-loop system to be exponentially mean square stable against actuator failures and input saturation. Finally, numerical examples are provided to show the effectiveness of the proposed method.