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排序方式: 共有135条查询结果,搜索用时 62 毫秒
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Qianqian Sun Yuwei Long Hongxi Li Shuang Pan Jidong Yang Shaopu Liu Xiaoli Hu 《Journal of fluorescence》2018,28(2):523-531
Caffeic acid (CA), a familiar color stabilizing reagent, has aroused general concern due to its uncontrolled addition, and thus the detection of CA is increasingly important. In our report, the bright carbon dots (CDs) were prepared via hydrothermal treatment with urea and citric acid act as raw material and their characteristics were discussed through X-ray diffraction (XRD), transmission electron microscopy (TEM) and so on. Impressively, the strong emission of the as-prepared CDs (Quantum Yield: 24.3%) decreased sharply upon a full reaction with the added CA. Hence, we first present an improved strategy for determining CA based upon the quenching of the strong emission of CDs. In this strategy, 0.79–100.0 µmol L??1 caffeic acid could be simply detected, and a detection limit of 0.24 µmol L??1 was allowed. Additionally, CA in red wine samples can be successfully detected by this method and the exploration of the quenching mechanism of the CA-CDs system was done. 相似文献
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Self‐Assembly of Pyridinium‐Functionalized Anthracenes: Molecular‐Skeleton‐Directed Formation of Microsheets and Microtubes 下载免费PDF全文
Dr. Jun Hu Peiyi Wang Prof. Yuan Lin Prof. Jidong Zhang Dr. Mark Smith Dr. Perry J. Pellechia Prof. Song Yang Prof. Baoan Song Prof. Qian Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(25):7603-7607
Two amphiphilic regioisomers, 9‐AP (1‐[11‐(9‐anthracenylmethoxy)‐11‐oxoundecyl]pyridinium bromide), and 2‐AP (1‐[11‐(2‐anthracenyl methoxy)‐11‐oxoundecyl]pyridinium bromide), were synthesized and their assembly behaviors were studied. Due to the anisotropic features of the anthracene structure, different substituted positions on the anthracene ring lead 9‐AP and 2‐AP to adapt “shaver” and “spatula”‐like molecular shapes, respectively, which consequently dictate the structure of their final assemblies. While “shaver”‐shaped 9‐AP assembled into microsheets, driven by π–π interactions, “spatula”‐shaped 2‐AP assembled into microtubular structures, promoted primarily by charge‐transfer interactions. 相似文献
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Yuan Jun Zhang Chujun Chen Honggang Zhu Can Cheung Sin Hang Qiu Beibei Cai Fangfang Wei Qingya Liu Wei Yin Hang Zhang Rui Zhang Jidong Liu Ye Zhang Huotian Liu Weifang Peng Hongjian Yang Junliang Meng Lei Gao Feng So Shukong Li Yongfang Zou Yingping 《中国科学:化学(英文版)》2020,63(8):1159-1168
Recent advances in material design for organic solar cells(OSCs) are primarily focused on developing near-infrared nonfullerene acceptors, typically A-DA′D-A type acceptors(where A abbreviates an electron-withdrawing moiety and D, an electron-donor moiety), to achieve high external quantum efficiency while maintaining low voltage loss. However, the charge transport is still constrained by unfavorable molecular conformations, resulting in high energetic disorder and limiting the device performance. Here, a facile design strategy is reported by introducing the "wing"(alkyl chains) at the terminal of the DA′D central core of the A-DA′D-A type acceptor to achieve a favorable and ordered molecular orientation and therefore facilitate charge carrier transport. Benefitting from the reduced disorder, the electron mobilities could be significantly enhanced for the"wing"-containing molecules. By carefully changing the length of alkyl chains, the mobility of acceptor has been tuned to match with that of donor, leading to a minimized charge imbalance factor and a high fill factor(FF). We further provide useful design strategies for highly efficient OSCs with high FF. 相似文献
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测量二级轻气炮/火炮弹丸在内弹道的速度历程,对轻气炮/火炮的设计、内弹道计算、弹道异常现象诊断分析具有重要作用。因为不同波长微波的传输特性在不同炮管中不同,不同目标的反射特性也不同,为获得最佳的测试结果,设计了两个波长的微波干涉测速系统。对二级轻气炮和高速火炮的内弹道速度进行了连续测量,并利用短时傅里叶变换与相位计算相结合的方法进行了数据处理。实验成功获取了完整的内弹道数据,所测弹丸炮口速度与光束遮断测速装置测试结果差异小于0.5%。通过对内弹道实验数据的分析,证实了二级轻气炮在某些装填条件下易出现碎弹现象。此外,首次观测到二级炮内弹道内前冲气体速度历史,可为研究高速气体的温度、压力、电离等状态提供数据支撑。 相似文献
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Mujuan Chen Jidong Liang Zhijian Zeng Xin Lin Shilong Zhang Lasheng Jiang 《Tetrahedron letters》2017,58(35):3437-3440
A new type of self-complexed bis-crown ether containing two bis(p-phenylene)-34-crown-10 (BPP34C10) ether rings and two secondary ammoniums has been synthesized and characterized. The formation of these bis-self-complexes has been identified by NMR spectroscopy, mass spectrometry and X-ray analysis. The acid/base controlled movement of these bis–crown ethers can mimic a flapping butterfly. 相似文献
9.
水热沉淀法制备掺铁二氧化钛中空球及其光催化性能 总被引:1,自引:0,他引:1
以碳球为模板剂, 采用水热沉淀法制备了不同配比掺 Fe 的 TiO2 (Fe-TiO2) 中空球, 并运用 X 射线粉末衍射、扫描电子显微镜、元素分析能谱、红外光谱和热重等方法对其进行了表征. 结果表明, 中空球为锐钛矿相, 大小为 0.5~3.20 ?m, 壳层厚度为 30~60 nm, 比表面积为 150~300 m2/g. 随着 Fe 掺杂量的增加, 中空球在可见光区的吸收强度逐渐增加. 光催化降解实验表明, 掺 Fe 后, TiO2 中空球的可见光催化活性升高, 其中 0.5% Fe-TiO2 在 80 min 内降解亚甲基蓝超过 75%. 同时还讨论了光催化机制. 相似文献
10.
He Wan Shasha Bai Haidong Li Junqiao Ding Zhiyuan Xie Jidong Zhang 《Journal of luminescence》2011,131(7):1393-1396
β phase polyoctylfluorene thin films were obtained by exposure to toluene vapor for various annealing times or dipping into a THF/methanol mixture. The photoluminescence and electroluminescence of PFO thin films decrease with increasing annealing time. Grazing incident X-ray diffraction of the thin films indicates that more and larger β phase crystallites will be generated in thin film exposed for longer time, which will lead to more defects that reduce photoluminescence and electroluminescence. By analyzing the mechanism of formation of β phase, we assume that the defects mainly come from the formation of out-of-plane crystalline structure. The assumption is confirmed by higher photoluminescence of β phase polyoctylfluorene thin film achieved by dipping into a THF/methanol mixture that has less out-of-plane crystalline structure. 相似文献