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排序方式: 共有2126条查询结果,搜索用时 15 毫秒
1.
Zhi Sun Mengfan Zhao Lihua Zuo Shengnan Zhou Feng Fan Qingquan Jia Lianping Xue Hanbing Li Jian Kang Xiaojian Zhang 《Journal of separation science》2022,45(2):518-528
Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra-high performance liquid chromatography–quadrupole/orbitrap high-resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra- and inter-day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6 and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex. 相似文献
2.
Fan Wang Zicheng Zuo Liang Li Kuo Li Feng He Zhongqing Jiang Yuliang Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15152-15157
A two‐dimensional (2D) carbon nanofilm with uniform artificial nanopores is an ideal material to ultimately suppress the fuel permeation in the proton exchange membrane fuel cells. Graphdiyne has great mechanical strength, high dimensional stability, and controllable nanopores, and has good prospects to play this crucial role. It is found that graphdiyne nanofilm with amino groups and natural nanopores can be easily prepared with high integrity. The aminated graphdiyne has good compatibility with the Nafion matrix owing to the acid–base interaction between them. The excellent comprehensive properties of graphdiyne in selectivity, dimensional stability, and integrity effectively improve the power performance and stability of fuel cells at wide temperature. Our results can be developed into a universal method that can easily realize the selective separation of ions and small molecules, and open a new way for the emerging applications in green energy. 相似文献
3.
Julia Holz Camilla Pfeffer Hualiang Zuo Dennis Beierlein Gunther Richter Elias Klemm Ren Peters 《Angewandte Chemie (International ed. in English)》2019,58(30):10330-10334
Gold nanoparticle catalysts are important in many industrial production processes. Nevertheless, for traditional C ?C cross‐coupling reactions they have been rarely used and Pd catalysts usually give a superior performance. Herein we report that in situ formed gold metal nanoparticles are highly active catalysts for the cross coupling of allylstannanes and activated alkylbromides to form C ?C bonds. Turnover numbers up to 29 000 could be achieved in the presence of active carbon as solid support, which allowed for convenient catalyst recovery and reuse. The present study is a rare case where a gold metal catalyst is superior to Pd catalysts in a cross‐coupling reaction of an organic halide and an organometallic reagent. 相似文献
4.
Chen Xiao-Lu Li Xiang-Yu Li Shuai-Shuai Bai Xue Li Tao Goud Erukala Yadaiah Zhong Chong-Min Zuo Ya-Jie 《Russian Journal of General Chemistry》2020,90(11):2163-2169
Russian Journal of General Chemistry - The Grubbs–Hoveyda catalysts have a wide range of applications in catalyzed formation of the carbon-carbon double bonds. In this study, several... 相似文献
5.
Yaogang Hu Peng Teng Wenyang Gao Xiaobing Zuo Lukasz Wojtas Randy W. Larsen Shengqian Ma Jianfeng Cai 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2501-2507
Foldamers offer an attractive opportunity for the design of novel molecules that mimic the structures and functions of proteins and enzymes including biocatalysis and biomolecular recognition. Herein we report a new class of nonnatural helical sulfono‐γ‐AApeptide foldamers of varying lengths. The crystal structure of the sulfono‐γ‐AApeptide monomer S6 illustrates the intrinsic folding propensity of sulfono‐γ‐AApeptides, which likely originates from the bulkiness of tertiary sulfonamide moiety. The two‐dimensional solution NMR spectroscopy data for the longest sequence S1 demonstrates a 10/16 right‐handed helical structure. Optical analysis using circular dichroism further supports well‐ defined helical conformation of sulfono‐γ‐AApeptides in solution containing as few as five building blocks. Future development of sulfono‐γ‐AApeptides may lead to new foldamers with discrete functions, enabling expanded application in chemical biology and biomedical sciences. 相似文献
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实验势精修是20世纪80年代英国散裂中子源无定型材料组开发的用于分析中子散射实验数据的软件. 实验势精修的目标是根据中子散射数据重建样品的三维原子结构. 在过去的几十年,实验势精修被广泛用于中子散射实验数据分析,为实验用户提供了可靠的分析结果. 但是实验势精修是基于共享内存并行计算(OpenMP)的Fortran程序,不支持计算机服务器集群跨节点并行加速和GPU加速;这限制了它的分析速度. 随着计算机服务器集群的广泛建设和GPU加速技术的普遍使用,有必要重新编写EPSR程序以提高运算速度. 本文使用面向对象的C++语言,开发了一套实现EPSR算法的开源软件包NeuDATool;软件通过MPI和CUDA C实现了计算机集群跨节点并行和GPU加速. 使用液态水和玻璃态二氧化硅的中子散射实验数据对软件进行了测试. 测试显示软件可以正确重建出样品的三维原子结构;并且模拟体系达到10万原子以上时,使用GPU加速可以比串行的CPU算法提高400倍以上的模拟速度. NeuDATool为中子实验用户尤其是对熟悉C++编程并希望定义特殊分析算法的实验科学家提供了一种新的选择. 相似文献
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Yan Zhou Dr. Fei Yu Dr. Jian Su Prof. Dr. Mohamedally Kurmoo Prof. Dr. Jing-Lin Zuo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18922-18926
To activate electronic and optical functions of the redox-active metal–organic framework, (Me2NH2)[InIII(TTFTB)]⋅0.7 C2H5OH⋅DMF (Me2NH2@ 1 , TTFTB=tetrathiafulvalene-tetrabenzoate, DMF=N,N-dimethylformamide), has been exchanged by tetrathiafulvalenium (TTF.+) and N,N′-dimethyl-4,4′-bipyridinium (MV2+). These cations provide electron carriers and photosensitivity. The exchange retains the crystallinity allowing single-crystal to single-crystal post-synthetic transformation to TTF@ 1 and MV@ 1 . Both TTF.+ and MV2+ enhance the electrical conductivity by a factor of 102 and the visible light induced photocurrent by 4 and 28 times, respectively. EPR evidences synergetic effect involving charge transfer between the framework redox-active TTFTB bridges and MV2+. The results demonstrate that functionalization of MOF by cation exchange without perturbing the crystallinity extends possibilities to achieve switchable materials. 相似文献