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71.
Nonlinear Dynamics - Dynamics in fractional order systems has been discussed extensively for presenting a possible guidance in the field of applied mathematics and interdisciplinary science. Within... 相似文献
72.
Nonlinear Dynamics - It is an effective way to improve network robustness by adding connectivity links. Although some addition strategies have been proposed, the addition cost in spatial networks... 相似文献
73.
Peng Yang Yaxin Sun Kaiyue Fu Li Zhang Guang Yang Jieyu Yue Yu Ma Jianrong Steve Zhou Bo Tang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2022,134(1):e202111778
We report a stereoselective conversion of terminal alkynes to α-chiral carboxylic acids using a nickel-catalyzed domino hydrocarboxylation-transfer hydrogenation reaction. A simple nickel/BenzP* catalyst displayed high activity in both steps of regioselective hydrocarboxylation of alkynes and subsequent asymmetric transfer hydrogenation. The reaction was successfully applied in enantioselective preparation of three nonsteroidal anti-inflammatory profens (>90 % ees) and the chiral fragment of AZD2716. 相似文献
74.
Dr. Zaifa Shi Dr. Yihuang Jiang Dr. Jingxiong Yu Prof. Shanjun Chen Prof. Jun Chen Prof. Zichao Tang Prof. Lansun Zheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(8):e202103546
At present, the reactivity of cyclic alkanes is estimated by comparison with acyclic hydrocarbons. Due to the difference in the structure of cycloalkanes and acycloalkanes, the thermodynamic data obtained by analogy are not applicable. In this study, a molecular beam sampling vacuum ultraviolet photoionization time-of-flight mass spectrometer (MB-VUV-PI-TOFMS) was applied to study the low-temperature oxidation of cyclopentane (CPT) at a total pressure range from 1–3 atm and low-temperature range between 500 and 800 K. Low-temperature reaction products including cyclic olefins, cyclic ethers, and highly oxygenated intermediates (e. g., ketohydroperoxide KHP, keto-dihydroperoxide KDHP, olefinic hydroperoxides OHP and ketone structure products) were observed. Further investigation of the oxidation of CPT – electronic structure calculations – were carried out at the UCCSD(T)-F12a/aug-cc-pVDZ//B3LYP/6-31+ G(d,p) level to explore the reactivity of O2 molecules adding sequentially to cyclopentyl radicals. Experimental and theoretical observations showed that the dominant product channel in the reaction of CPT radicals with O2 is HO2 elimination yielding cyclopentene. The pathways of second and third O2 addition – the dissociation of hydroperoxide – were further confirmed. The results of this study will develop the low-temperature oxidation mechanism of CPT, which can be used for future research on accurately simulating the combustion process of CPT. 相似文献
75.
Dr. Hongying Tang Jian Gao Prof. Yidong Wang Prof. Nanwen Li Dr. Kang Geng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(70):e202202064
Great efforts have been conducted to develop high temperature proton exchange membrane fuel cell (HT-PEMFC) due to its features of enhanced electrocatalyst reactivity, simplified hydrothermal management system and high CO tolerance of catalysts, and remarkable progress has been achieved. However, the easy leaching of phosphoric acid (PA) from the membranes during operation limits its commercial scale-up in complicated environments. This concept here mainly focuses on the recent developments for mitigation of PA loss in PEMs. The probable mechanisms of PA loss are proposed. The approaches to improve PA retention for example via introduction of phosphonic acid by covalent bond, using ion-pairs interaction and siphoning effect, and blending with inorganic nanoparticles are described in detail. Among these strategies, the siphoning effect from the intrinsic microporous PEMs is the most efficient and enables the cell to operate flexibly within a broad temperature range. Therefore, this concept may provide new ideas for the scientists to retain PA, to improve the cell performance and expand the potential applications of PA doped PEMs at elevated humidity and wide temperature range. 相似文献
76.
Weiquan Xu Jin-Yu Chao Dr. Bohan Tang Prof. Zhan-Ting Li Prof. Jiang-Fei Xu Prof. Xi Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(63):e202202200
A supramolecular organic framework-type photocatalyst, named TM-SOF, is constructed by the self-assembly of cucurbit[8]uril and a tetra-arm monomer containing four N, N’-dimethyl 2,5-bis(4-pyridinium)thiazolo[5,4-d]thiazole (MPT) moieties. Benefiting from the multivalent assembly, a photocatalytically active supramolecular MPT dimer can be stably formed in TM-SOF. In addition, TM-SOF exhibits better stability against temperature, substrate, and light irradiation. As a result, TM-SOF shows a significantly improved performance for the photocatalytic aerobic oxidation of aryl boronic acids and thioethers. It is anticipated that this line of research will provide a facile approach for fabricating high-performance supramolecular photocatalysis systems. 相似文献
77.
Li Mengya Yan Pengfei Liu Jie Pei Ying Zheng Xuejing Tang Keyong Wang Fang 《Cellulose (London, England)》2022,29(3):1609-1621
Cellulose - One-step acid hydrolysis was successfully employed to prepare carboxylated cellulose nanofibrils (CCNFs) from pomelo peel waste with the mixture of hydrochloric acid and citric acid... 相似文献
78.
Jiaqi Ke Yufei Zhang Yibo Zhang Minghui Ye Zicheng Zhang Yongchao Tang Xiaoqing Liu Prof. Cheng Chao Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(54):e202201687
Rechargeable zinc-ion batteries (ZIBs) are potential for grid-scale applications owing to their safety, low price, and available sources. The development of ZIBs cathode with high specific capacity, wide operating voltage window and stable cyclability is urgently needed in next-generation commercial batteries. Herein, we report a structurally crystalline-stable Mn(VO3)2 nanobelts cathode for ZIBs prepared via a facile hydrothermal method. The as-synthesized Mn(VO3)2 exhibited high specific capacity of 350 mAh g−1 at 0.1 A g−1, and maintained a capacity retention of 92 % after 10,000 cycles at 2 A g−1. It also showed good rate performance and obtained a reversible capacity of up to 200 mAh g−1 after 600 cycles at 0.2 A g−1 under −20 °C. The electrochemical tests suggest that Mn(VO3)2 nanobelts impart fast Zn2+ ions migration, and the introduction of manganese atoms help make the structures more indestructible, leading to a good rate performance and prolonged cycle lifespan. 相似文献
79.
Chen Zi-Han Li Yue-Hua Qi Ming-Yu Tang Zi-Rong Xu Yi-Jun 《Research on Chemical Intermediates》2022,48(1):1-12
Research on Chemical Intermediates - Owing to the simultaneous utilization of photogenerated electrons and holes, coupling light-driven hydrogen (H2) evolution reaction (HER) and biomass-derived... 相似文献
80.
Double-layered graphene sheets(DLGSs) can be applied to the development of a new generation of nanomechanical sensors due to their unique physical properties. A rectangular DLGS with a nanoparticle randomly located in the upper sheet is modeled as two nonlocal Kirchhoff plates connected by van der Waals forces. The Galerkin strip transfer function method which is a semi-analytical method is developed to compute the natural frequencies of the massplate vibrating system. It can give exact closed-form solutions along the longitudinal direction of the strip. The results obtained from the semi-analytical method are compared with the previous ones, and the differences between the single-layered graphene sheet(SLGS) and the DLGS mass sensors are also investigated. The results demonstrate the similarity of the in-phase mode between the SLGS and DLGS mass sensors. The sensitivity of the DLGS mass sensor can be increased by decreasing the nonlocal parameter, moving the attached nanoparticle closer to the DLGS center and making the DLGS smaller. These conclusions are helpful for the design and application of graphene-sheet-based resonators as nano-mass sensors. 相似文献