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371.
Ching Hsuan Lin Chin Kuang Hsu Meng Wei Wang Shenghong A. Dai Tzong Yuan Juang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(3):390-400
Four novel diamines (9–12) were prepared by a two‐step procedure from phosphinated phenols (1–4) that were prepared from acid‐fragmentation of four bisphenols, including bisphenol A, 4,4′‐isopropylidenebis(2,6‐dimethylphenol), cis(4‐hydroxyphenyl)cyclohexane, and 9,9′‐bis(4‐hydroxyphenyl)fluorene, followed by nucleophilic addition of 9,10‐dihydro‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO). Copolyimides based on (9–12) /4,4′‐diaminodiphenyl ether (ODA)/dianhydride were prepared. The structure‐property relationship on the copolyimides was discussed. Due to the structural similarity, (9) /ODA‐based copolyimides were compared with (10) /ODA‐based copolyimides, while (11) /ODA‐based copolyimides were compared with (12) /ODA‐based copolyimides. The dimethyl substitutents cause (10) /ODA‐based copolyimides to display higher Tg, modulus, dimensional stability, contact angle, and better solubility than (9) /ODA‐based copolyimides. (12) /ODA‐based copolyimides that exhibit fluorene moieties display higher Tg and thermal stability, but a lower contact angle and poorer solubility than (11) /ODA‐based copolyimides that exhibit cyclohexane moieties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 390–400 相似文献
372.
Incarceration of Higher‐Order Fullerenes within Cyclotriveratrylene‐Based Hemicarcerands Allows Selective Isolation of C76, C78, and C84 from a Commercial Fullerene Mixture
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Kuang‐Shun Liu Dr. Ming‐Jhe Li Prof. Chien‐Chen Lai Prof. Sheng‐Hsien Chiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17468-17476
Size‐complementary cyclotriveratrylene (CTV)‐based hosts can incarcerate C76, C78, and C84, thus allowing the selective isolation of these higher‐order fullerenes from a commercially available mixture of fullerenes. The hemicarceplexes, formed after the encapsulation of the size‐complementary fullerenes within the hosts, are isolated by column chromatography and released at elevated temperature, thereby leading to the isolation of C76/C78 and C84 in good purities (up to 95 and 88 %, respectively). 相似文献
373.
Min Zhang Yang‐Wen Ou Xue‐Xiang Chen Yong Cao Yong Kuang Zhu‐Qing Gong Sheng Peng Yun‐Jiao Chen 《Helvetica chimica acta》2011,94(10):1820-1824
A further chemical investigation of the plant Rubus corchorifolius L. f., collected in Hunan Province, afforded two new ent‐kauranoids 6 and 7 . Their structures were elucidated by various spectroscopic methods. 相似文献
374.
Jianfei Zhu Jian Wu Xiubao Sui Xiaodong Kuang Qian Chen Guohua Gu 《Optical Review》2018,25(5):638-646
Nowadays, super-resolution is becoming more and more important in most optical imaging systems and image processing applications due to current resolution limit of charged couple device (CCD) and complementary metal-oxide semiconductor (CMOS). In this paper, we proposed a novel single-image super-resolution algorithm, which combines collaborative representation into manifold-preserving approach. The main contributions of our work can be summarized into two points. First, supporting bases which are used to calculate the mapping relationship between low-resolution (LR) images and high-resolution (HR) images are obtained by applying collaborative representation on the neighborhoods of the dictionary atoms, where the neighborhoods are clustered from the whole training sample pools. Second, to achieve a balance between execution speed and reconstruction quality, a global solution for our framework is constructed by transferring the online calculating process to offline. We demonstrate better results on commonly used datasets, showing both better visual performance and higher index values compared to other methods. 相似文献
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378.
Iridium(III) Anthraquinone Complexes as Two‐Photon Phosphorescence Probes for Mitochondria Imaging and Tracking under Hypoxia
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Lingli Sun Yu Chen Shi Kuang Guanying Li Ruilin Guan Jiangping Liu Prof. Liangnian Ji Prof. Dr. Hui Chao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(26):8955-8965
In the present study, four mitochondria‐specific and two‐photon phosphorescence iridium(III) complexes, Ir1 – Ir4 , were developed for mitochondria imaging in hypoxic tumor cells. The iridium(III) complex has two anthraquinone groups that are hypoxia‐sensitive moieties. The phosphorescence of the iridium(III) complex was quenched by the functions of the intramolecular quinone unit, and it was restored through two‐electron bioreduction under hypoxia. When the probes were reduced by reductase to hydroquinone derivative products under hypoxia, a significant enhancement in phosphorescence intensity was observed under one‐ (λ=405 nm) and two‐photon (λ=720 nm) excitation, with a two‐photon absorption cross section of 76–153 GM at λ=720 nm. More importantly, these probes possessed excellent specificity for mitochondria, which allowed imaging and tracking of the mitochondrial morphological changes in a hypoxic environment over a long period of time. Moreover, the probes can visualize hypoxic mitochondria in 3D multicellular spheroids and living zebrafish through two‐photon phosphorescence imaging. 相似文献
379.
Guowen Kuang Qiushi Zhang Deng Yuan Li Xue Song Shang Dr. Tao Lin Prof. Dr. Pei Nian Liu Prof. Dr. Nian Lin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8028-8032
Cross‐coupling is of great importance in organic synthesis. Here it is demonstrated that cross‐coupling of aryl‐bromide and porphyrin‐bromide takes place on a Au(111) surface in vacuo. The products are oligomers consisting of porphyrin moieties linked by p‐phenylene at porphyrin’s meso‐positions. The ratio of the cross‐coupled versus homocoupled bonds can be regulated by the reactant concentrations. Kinetic Monte Carlo simulations were applied to determine the activation barrier. It is expected that this reaction can be employed in other aryl‐bromide precursors for designing alternating co‐polymers incorporating porphyrin and other functional moieties. 相似文献
380.
针对传统基于随机初始化的变分贝叶斯独立分量分析(VBICA)方法的不足,即随机初始化导致经过不同的学习得到的分离结果存在差异性,提出了一种基于主分量分析(PCA)的变分贝叶斯独立分量分析的盲源分离方法,在提出的方法中,利用PCA来初始化模型参数。并与传统的变分贝叶斯独立分量分析方法进行对比。仿真结果验证了该方法的有效性,提出的方法不仅比传统的VBICA方法取得了更好的分离性能,并且保持分离结果的稳定性,克服了传统的VBICA方法的不足。 相似文献