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51.
Dr. Shaomin Peng Dr. Qi Wei Dr. Bingzhe Wang Dr. Zhipeng Zhang Hongcheng Yang Guotao Pang Prof. Kai Wang Prof. Guichuan Xing Prof. Xiao Wei Sun Prof. Zikang Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22340-22346
Quasi-two-dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates. However, strong exciton–phonon interactions caused by mechanical softening of the surface act as a bottleneck in improving their suitability for a wide range of lighting and display applications. Moreover, it is not easily available to tune the phonon interactions in bulk films. Here, we adopt bottom-up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids. By optimizing component domains, the phonon coupling strength can be reduced by a factor of 2 driven by the delocalization of 2D excitons in out-of-plane orientations. It shows the picosecond energy transfer originated from the Förster resonance energy transfer (FRET) efficiently competes with the exciton–phonon interactions in the binary system. 相似文献
52.
Ruirui Xu Kun Wang Haoying Liu Prof. Dr. Weijun Tang Dr. Huaming Sun Prof. Dr. Dong Xue Prof. Dr. Jianliang Xiao Prof. Dr. Chao Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22143-22148
A ruthenium-catalyzed formal anti-Markovnikov hydroamination of allylic alcohols for the synthesis of chiral γ-amino alcohols is presented. Proceeding via an asymmetric hydrogen-borrowing process, the catalysis allows racemic secondary allylic alcohols to react with various amines, affording enantiomerically enriched chiral γ-amino alcohols with broad substrate scope and excellent enantioselectivities (68 examples, up to >99 % ee). 相似文献
53.
Dr. Yaru Gong Chao Qin Yuteng Zhang Prof. Chunyi Sun Prof. Qinhe Pan Xinlong Wang Zhongmin Su 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(49):22218-22222
Systematic design and self-assembly of metal–organic polyhedra with predictable configurations has been a long-standing challenge in crystal engineering. Herein a concave polyoxovanadate cluster, [V6O6(OCH3)9(SO4)4]5−, which can be generated in situ under specific reaction conditions, is reported. Based on this cluster, a potential trivalent molecular building block, [V6O6(OCH3)9(SO4)(CO2)3]2−, can be obtained by the bridging-ligand-substitution strategy and it possesses appropriate angle information for the design of molecular cubes. Utilizing the face-directed assembly of the trivalent molecular building block and a diverse set of tetratopic carboxylate linkers, a series of metal–organic cubes ( VMOC-1 – VMOC-5 ) with the same topology but different functionalities and dimensions were designed and constructed. An inclusion study using VMOC-3 shows that they are potential molecular receptors for selective capture of size-matching polycyclic aromatic hydrocarbon guest molecules. 相似文献
54.
通过第一原理电子结构计算来研究有序多孔纳米网的电导特性变化的能带机理.能带结构分析结果表明:石墨烯纳米网超晶格(3m,3n)(m和n为整数)的电子本征态在布里渊区中心点发生四重简并;碳空位孔洞规则排列形成的石墨烯纳米网具有由简并态分裂形成的宽度可调带隙,无论石墨烯的两个子晶格是否对等.在具有磁性网孔阵列的石墨烯纳米网中,反铁磁耦合使对称子晶格的反演对称性增加了一项量子限制条件,导致能带结构在K点的二重简并态分裂成带隙.通过控制网孔密度能够有效调节石墨烯纳米网的带隙宽度,为实现新一代石墨烯纳米电子器件提供了理论依据. 相似文献
55.
56.
介绍了一种条带束流位置监测器(BPM)的设计与仿真方法。在国家同步辐射实验室"太赫兹近场高通量材料物性测试系统"工程项目中,针对波荡器出口处真空室非正交对称性的问题,设计了矩形真空室和跑道形真空室下的两种非正交对称性条带BPM,并与传统的圆形真空室下条带BPM进行对比。基于边界元法,利用MATLAB软件分别对三种真空室下的条带BPM进行建模和仿真。仿真结果表明:相对于传统的圆形真空室下条带BPM,矩形和跑道形真空室下条带BPM灵敏度提高了30%,阻抗匹配误差相对降低了20%,束流位置拟合误差降低了80%。考虑加工精度,矩形真空室下的条带BPM更适用于该工程。 相似文献
57.
This paper proposes a protocol for lottery and a protocol for auction on quantum Blockchain. Our protocol of lottery satisfies randomness, unpredictability, unforgeability, verifiability, decentralization and unconditional security. Our protocol of auction satisfies bid privacy, posterior privacy, bids’ binding, decentralization and unconditional security. Except quantum Blockchain, the main technique involved in both protocols is quantum bit commitment. 相似文献
58.
Chao Zhang Shuyue Wang Fei Guo Ting Ma Longfei Zhang Linlin Sun Yingzi Wang Xuelan Zhang 《Biomedical chromatography : BMC》2020,34(4):e4794
Just as natural saponins transform into aglycones, secondary glycosides and their derivatives using biotransformation technology, steroidal saponins may also undergo similar transformation after stir-frying. The purpose of this study was to elucidate the variations and the reasons for these variations in the contents of steroidal saponins in Fructus Tribuli (FT) during a stir-frying treatment. Stir-fried FT was processed in different time–temperature conditions. An UHPLC–MS/MS method was established and fully validated for quantitative analysis. In addition, the simulation processing products of tribuluside A, terrestroside B, terrestrosin K, terrestrosin D and 25R-tribulosin were determined by qualitative analysis using UHPLC–Q-TOF–MS. The established UHPLC–MS/MS method provides a rapid, flexible, and reliable method for the quality assessment of FT. The present study revealed that furostanol saponins with a C22-OH group could transform into corresponding furostanol saponins with a C-20–C-22 double bond (FSDB) via dehydroxylation. Additionally, FSDB could be successively converted into its secondary glycosides via a deglycosylation reaction. The transformation of spirostanol saponins into corresponding aglycones via deglycosylation led to a decrease in spirostanol saponins and an increase in aglycones. The results of this research provided scientific evidence of variation and structural transformation among steroidal saponins. These findings might be helpful for elucidating the processing mechanism of FT. 相似文献
59.
Yangang Cheng Yan Liu Jinyan Tan Yanping Sun Wei Guan Yuan Liu Bingyou Yang Haixue Kuang 《Biomedical chromatography : BMC》2020,34(9):e4881
Our previous work demonstrated that total withanolides of Datura metel L. leaves (TWD) exhibited excellent therapeutic effects on psoriasis. However, current knowledge of its mechanisms is incomplete. In this study, integrated spleen and thymus untargeted metabolomics were used to analyze the changes in endogenous metabolites underlying the immunosuppressive activity of TWD on psoriasis animal models induced by imiquimod. The results suggested that TWD treatment markedly attenuated imiquimod-induced psoriasis and showed significant immunosuppressive activity as evidenced by decreased elevation index of spleen and thymus. Meanwhile, TWD significantly reversed the elevation of immunoregulatory factors, including IL-10, IL-17, IL-22 and IL-23. Multivariate trajectory analysis revealed that TWD treatment could restore the psoriasis-disturbed spleen and thymus metabolite profiles towards the normal metabolic status. A total of 25 and 27 metabolites associated with the immunomodulatory effects for which levels changed markedly upon treatment have been identified in spleen and thymus, respectively. These differential metabolites were mainly involved in amino acid metabolism, nucleotide metabolism, fatty acid metabolism and lipid metabolism. Our investigation provided a holistic view of TWD for intervention in psoriasis through immunoregulation and provided further scientific information in vivo about a clinical value of TWD for psoriasis. 相似文献
60.
Xiao Sun Li Zhang Yu Cao Jinhua Li Atanas G. Atanasov Linfang Huang 《Biomedical chromatography : BMC》2020,34(12):e4949
Balanophora involucrata J. D. Hooker has been known to possess potential anti-inflammatory and antibacterial activities; however, its antiviral activity has not been evaluated so far. In order to find new neuraminidase inhibitors (NAIs), the neuraminidase (NA) inhibition activity of different B. involucrata extracts was evaluated. In this study, an in vitro NA inhibition assay was performed to identify which extract of B. involucrata exhibits (maximal) inhibitory activity against NA. Ultra high performance liquid chromatography/quadrupole time-of-flight–tandem mass spectroscopy (MS/MS) and molecular docking techniques were used to identify the specific compounds responsible for the anti-influenza activity of the extract, and to explore the potential natural NAIs. The ethyl acetate extract of B. involucrata exhibited significant inhibitory activity against NA with 50% inhibitory concentration (IC50) value of 159.5 μg/mL. Twenty compounds were identified according to the MS/MS spectra; among them two compounds (quercitrin and phloridzin) showed obvious inhibitory activity against NA, with IC50 of 311.76 and 347.32 μmol/L, respectively. This study suggested that B. involucrata can be a potential natural source of NAIs and may be useful in the fight against ferocious influenza viruses. 相似文献