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981.
Yuewei Zhang Dongdong Zhang Jinbei Wei Xiangchen Hong Yang Lu Deping Hu Guomeng Li Ziyang Liu Yang Chen Lian Duan 《Angewandte Chemie (International ed. in English)》2020,59(40):17499-17503
Pure green emitters are essential for realizing an ultrawide color gamut in next‐generation displays. Herein, by fusing the difficult‐to‐access aza‐aromatics onto B (boron)–N (nitrogen) skeleton, a hybridized multi‐resonance and charge transfer (HMCT) molecule AZA‐BN was successfully synthesized through an effective one‐shot multiple cyclization method. AZA‐BN shows pure green fluorescence with photoluminance quantum yield of 99.7 %. The corresponding green device exhibits a maximum external quantum efficiency and power efficiency of 28.2 % and 121.7 lm W?1, respectively, with a full width half maximum (FWHM) of merely 30 nm and Commission Internationale de l'Eclairage (CIE) coordinate y of 0.69, representing the purest green bottom‐emitting organic light‐emitting diode. 相似文献
982.
Junjun Hou Meihuizi Jiang Xiao He Pengchao Liu Chang Long Lian Yu Zhiwei Huang Jin Huang Lianshan Li Zhiyong Tang 《化学:亚洲杂志》2020,15(15):2341-2345
To separate small molecules from the solvent with high permeability and selectivity, the membrane process is thought to be highly effective with much lower energy consumption when compared to the traditional thermal‐based separation process. To achieve high solvent permeance, a sub‐10 nm thick polyamide nanofiltration membrane was synthesized through interfacial polymerization of ethidium bromide (EtBr) and trimesoyl chloride (TMC). Thanks to the extremely low solubility of the EtBr monomer in the organic phase, the polymerization process was strictly limited at the interface of the water and hexane, leading to an ultrathin polyamide membrane with a thickness down to sub‐10 nm. When used in nanofiltration, these ultrathin membranes display ultrafast water permeation of 40 liter per square meter per hour per bar (L m?2 h?1 bar?1), and a high Congo red rejection rate of 93 %. This work demonstrates a new route to synthesize ultrathin polyamide membranes by the traditional interfacial polymerization. 相似文献
983.
Chitosan nanoparticles with magnetic properties can be potentially used as separation materials in adsorption of oil for enhanced oil recovery. Different from the traditional surfactants, the novel magnetic Co0.5Zn0.5Fe2O4-chitosan nanoparticles are of excellent biodegradation and a high level of controllability. The Co0.5Zn0.5Fe2O4-chitosan nanoparticles with core-shell structure were prepared successfully. The image of transmission electron microscope and the scanning electron microscopy showed that the cubic-shape magnetic Co0.5Zn0.5Fe2O4-particles were encapsulated by the spherical chitosan nanoparticles. The size of the Co0.5Zn0.5Fe2O4-chitosan nanoparticles was below 100 nm. The saturated magnetization of the Co0.5Zn0.5Fe2O4-chitosan nanoparticles could reach 80 emu g?1 and showed the characteristics of superparamagnetism at the same time. The evaluation on the interfacial properties of the product demonstrated that the interfacial tension between crude oil and water could be reduce to ultra-low values (to about 10?3 mN m?1) when the magnetic Co0.5Zn0.5Fe2O4-chitosan nanoparticle was used in several blocks in Shengli Oilfield without other additives. Meanwhile, the magnetic Co0.5Zn0.5Fe2O4-chitosan nanoparticles possessed good salt-resisting capacity. 相似文献
984.
Asymmetric Reduction of α‐Amino Ketones with a KBH4 Solution Catalyzed by Chiral Lewis Acids 下载免费PDF全文
Peng He Haifeng Zheng Prof. Dr. Xiaohua Liu Xiangjin Lian Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13482-13486
An efficient enantioselective reduction of α‐amino ketones with potassium borohydride solution catalyzed by chiral N,N′‐dioxide–metal complex catalysts was accomplished under mild reaction conditions for the first time. It provided a simple, convenient, and practical approaches for obtaining synthetically important chiral β‐amino alcohols in good to excellent yields (up to 98 %) and enantioselectivities (up to 97 % ee). 相似文献
985.
Dong-Sheng Lian Shu-Jin Zhao Jian Li Bing-Ling Li 《Analytical and bioanalytical chemistry》2014,406(25):6129-6150
Numerous strategies have been developed to mitigate the intrinsic low detection sensitivity that is a limitation of capillary electrophoresis. Among them, in-line stacking is an effective strategy to address the sensitivity challenge, and among the different stacking techniques, stacking based on field amplification is the most effective and simplest method of achieving high sensitivity without special complicated mechanisms or operations. This review introduces several stacking techniques based on field amplification. Field-amplified sample stacking, large-volume sample stacking, matrix field-amplified stacking injection (FASI), head-column FASI, matrix FASI combined with head-column FASI, FASI coupled with extraction and clean-up methods, electrokinetic supercharging, cation–anion selective exhaustive injection-sweeping-micellar electrokinetic chromatography, and newly developed techniques based on field amplification combined with other methods are included, and examples of straightforward methods for solving the sensitivity problem are provided. We also present a brief overview of the advantages, limitations, and future developments of these techniques. Graphical Abstract
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986.
CHEN Li XU Jian YUAN Hua YANG Shu Min WANG Lian Sheng WU Yan Qing ZHAO Jun CHEN Ming LIU Hai Gang LI Sha Yu TAI Ren Zhong WANG Shuang Qing YANG Guo Qiang 《中国科学:化学(英文版)》2014,(12)
A device was designed and assembled to analyze the outgassing of molecular glass(MG)photoresists under extreme ultraviolet(EUV)exposure.The outgassing of the photoresists with different components and different concentrations of tert-butoxycarbonyl(t-Boc),photo-generated acid(PAG),and acid quencher was systematically investigated.Based on experiments,some solutions for reducing the outgassing of MG photoresists were proposed. 相似文献
987.
Yifen Luo Bozhou Wang Guofang Zhang Yanshui Zhou Peng Lian 《Journal of heterocyclic chemistry》2013,50(2):381-385
1,3‐Dipolar cycloaddition reaction between nitrile oxide and alkyne was used to capture 3‐amino‐4‐oxycyanofurazan (AOCF), which was considered as the key intermediate during the synthesis of 3,4‐bis(4‐aminofurazano‐3‐yl)furoxan (DATF) from 3‐amino‐4‐chloroximinofurazan. The isolated isoxazoles from the reaction afforded evidences for the existence of AOCF. The structures of the isoxazoles were characterized by IR, 1H NMR, 13C NMR, MS, and elemental analysis. In addition, single crystal X‐ray diffraction of one isoxazole was obtained. 相似文献
988.
989.
990.
本文对带相依终止事件的复发事件数据提出了一个联合建模分析方法,用一个带脆弱变量的可加可乘比率模型来刻画复发事件过程,还用带脆弱变量的Cox风险率模型来刻画终止事件过程,而且这两个过程的相依性由脆弱变量来刻画.我们利用估计方程的方法,对模型参数进行了估计,给出了所得估计的渐近性质.同时,通过数值模拟分析验证了估计的渐近性质.最后,利用该方法分析了弗吉尼亚大学慢性心脏病病人医疗诊费数据. 相似文献