排序方式: 共有33条查询结果,搜索用时 15 毫秒
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Zhang Mingjie Song Yang Abdelkefi Abdessattar Yu Haiyan Wang Junlei 《Nonlinear dynamics》2022,108(3):1867-1884
Nonlinear Dynamics - Vortex-induced vibration (VIV) systems with stiffness nonlinearity have received increasing attention because the stiffness nonlinearity can broaden the effective flow velocity... 相似文献
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Cerium oxide based coatings were prepared on AA2024 Al alloy by brush plating. The characteristic of this technology is that hydrogen peroxide, which usually causes the plating solution to be unstable, is not necessary in the plating electrolyte. The coating showed laminated structures and good adhesive strength with the substrate. X-ray diffraction and X-ray photoelectron spectroscopy analysis showed that the coatings were composed of Ce(III) and Ce(IV) oxides. The brush plated coatings on Al alloys improved corrosion resistance. The influence of plating parameters on structure and corrosion resistance of the cerium oxide based coating was studied. 相似文献
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A novel amphiphilic silica‐based monolithic column having surface‐bound octanoyl‐aminopropyl moieties was successfully prepared by a one‐step in situ derivatization process. As expected, the amphiphilic monolithic column exhibited RP chromatographic behavior toward non‐polar solutes (e.g., alkyl benzenes) with high column performance. As the pH of the buffer inside the column increases, the EOF changed from −2.65×10−8m2 V−1s−1 at pH 3.0 to 1.20×10−8 m2 V−1s−1 at pH 8.0 with the reversion of EOF at about pH 6.4. Using acidic mobile phase, five aromatic acids can be efficiently separated in less than 6 min under co‐EOF conditions. For basic compounds, symmetrical peaks were obtained due to the existence of hydrophilic acyl amide group, which can effectively minimize the adsorption of the positively charged basic analyte to the silica‐based surface of the capillary column. 相似文献
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Muhammad Asif Muhammad Ajmal Ghazala Ashraf Nadeem Muhammad Ayesha Aziz Tayyaba Iftikhar Junlei Wang Hongfang Liu 《Current Opinion in Electrochemistry》2020
Herein, we have summarized and argued about biomarkers and indicators used for the detection of severe acute respiratory syndrome coronavirus 2. Antibody detection methods are not considered suitable to screen individuals at early stages and asymptomatic cases. The diagnosis of coronavirus disease 2019 using biomarkers and indicators at point-of-care level is much crucial. Therefore, it is urgently needed to develop rapid and sensitive detection methods which can target antigens. We have critically elaborated key role of biosensors to cope the outbreak situation. In this review, the importance of biosensors including electrochemical, surface enhanced Raman scattering, field-effect transistor, and surface plasmon resonance biosensors in the detection of severe acute respiratory syndrome coronavirus 2 has been underscored. Finally, we have outlined pros and cons of diagnostic approaches and future directions. 相似文献
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新型吡唑Schiff碱及金属配合物的合成和抑菌活性 总被引:2,自引:0,他引:2
以3-氨基-4-氰基吡唑和芳醛为原料合成了10个新型吡唑Schiff碱及铜(II)、镍(II)、锌(II)、钴(II) 4个金属配合物. 用元素分析, IR, 1H NMR及单晶解析表征了Schiff碱及金属配合物的结构. 测定了Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌、枯草杆菌和绿脓杆菌的抑菌活性. 生物活性研究表明, Schiff碱及金属配合物对金黄色葡萄球菌、大肠杆菌和绿脓杆菌都有较好的抑菌效果, 其中铜(II)和锌(II)配合物对金黄色葡萄球菌和大肠杆菌的抑菌活性最好. 相似文献
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Wenhuai Feng Junlei Tao Gengling Liu Guo Yang Dr. Jun-Xing Zhong Yuxuan Fang Li Gong Prof. Shaopeng Yang Prof. Wu-Qiang Wu 《Angewandte Chemie (International ed. in English)》2023,62(17):e202300265
Mixed-cation, small band-gap perovskites via rationally alloying formamidinium (FA) and methylammonium (MA) together have been widely employed for blade-coated perovskite solar cells with satisfied efficiencies. One of the stringent challenges lies in difficult control of the nucleation and crystallization kinetics of the perovskites with mixed ingredients. Herein, a pre-seeding strategy by mixing FAPbI3 solution with pre-synthesized MAPbI3 microcrystals has been developed to smartly decouple the nucleation and crystallization process. As a result, the time window of initialized crystallization has been greatly extended by 3 folds (i.e. from 5 s to 20 s), which enables the formation of uniform and homogeneous alloyed-FAMA perovskite films with designated stoichiometric ratios. The resultant blade-coated solar cells achieved a champion efficiency of 24.31 % accompanied by outstanding reproducibility with more than 87 % of the devices showing efficiencies higher than 23 %. 相似文献
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Metal-organic framework MIL-53(Al) was synthesized by a solvothermal method using aluminum nitrate as the aluminium source and 1,4-benzenedicarboxylic acid (H2BDC) as the organic ligand. The structure of samples was characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The catalytic activity and recyclability of MIL-53(Al) catalyst for the Friedel-Crafts acylation reaction of indole with benzoyl chloride were evaluated. The reaction conditions were optimized and a reaction mechanism was suggested. The results showed that the MIL-53(Al) catalyst exhibited good catalytic activity and recyclability for the Friedel-Crafts acylation reaction. When the molar ratio of indole and MIL-53(Al) catalyst was 1:0.06 (n 1:n catalyst), the molar ratio of indole and benzoyl chloride was 1:3, and the solvent was dichloromethane, the conversion of indole could reach 97.1% and the selectivity of 3-acylindole could reach 81.1% at 25 °C after 8 h. The catalyst can be reused without significant degradation in catalytic activity. After the catalyst was reused five times, the conversion of indole was 87.6% and the selectivity of 3-acylindole was 79.5%. 相似文献
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Chubei Wang Jianwei Zhou Xingbin Lv Junlei Wen Hongwu He 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):1334-1339
Abstract A new, environmentally benign, convenient, and easy method of synthesizing tertiary α-hydroxyphosphonates by the triethylamine-catalyzed hydrophosphonylation of unactivated ketones was developed. In the presence of triethylamine, aromatic or heteroaromatic ketones can react with phosphite to form tertiary α-hydroxyphosphonates under solvent-free and mild conditions. The proposed method was also suitable for functionalized ketones. 相似文献
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Junlei Zhu Yuehua Bu Miltiades P. Pardalos Hongwei Du Huijuan Wang Bin Liu 《Journal of Global Optimization》2018,72(3):539-552
The optimal channel assignment is an important optimization problem with applications in optical networks. This problem was formulated to the L(p, 1)-labeling of graphs by Griggs and Yeh (SIAM J Discrete Math 5:586–595, 1992). A k-L(p, 1)-labeling of a graph G is a function \(f:V(G)\rightarrow \{0,1,2,\ldots ,k\}\) such that \(|f(u)-f(v)|\ge p\) if \(d(u,v)=1\) and \(|f(u)-f(v)|\ge 1\) if \(d(u,v)=2\), where d(u, v) is the distance between the two vertices u and v in the graph. Denote \(\lambda _{p,1}^l(G)= \min \{k \mid G\) has a list k-L(p, 1)-labeling\(\}\). In this paper we show upper bounds \(\lambda _{1,1}^l(G)\le \Delta +9\) and \(\lambda _{2,1}^l(G)\le \max \{\Delta +15,29\}\) for planar graphs G without 4- and 6-cycles, where \(\Delta \) is the maximum vertex degree of G. Our proofs are constructive, which can be turned to a labeling (channel assignment) method to reach the upper bounds. 相似文献