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951.
Phu H. Dang Linh T. T. Nguyen Hue T. T. Nguyen Tho H. Le Truong N. V. Do Hai X. Nguyen 《Natural product research》2019,33(20):2883-2889
From an EtOAc-soluble fraction of the stem barks of Swintonia floribunda (Anacardiaceae), one new dimeric alkylresorcinol named integracin E (1), together with 4 known compounds (2–5) were isolated. Their chemical structures were elucidated based on the spectroscopic data interpretation. The absolute configuration of 1 was determined by the specific rotation analysis of its acid-catalyzed hydrolysis product. Compound 1 showed potent tyrosinase inhibitory activity with an IC50 value of 48.2?μM. 相似文献
952.
Synthesis of V5+‐doped Ag/AgCl photocatalysts with enhanced visible light photocatalytic activity 下载免费PDF全文
V5+‐doped Ag/AgCl photocatalysts were prepared via the ion exchange method. The catalysts were characterized using X‐ray diffractometry, transmission electron microscopy, and energy‐dispersive X‐ray, X‐ray photoelectron, Fourier transform infrared and ultraviolet–visible spectroscopies. The V5+‐doped Ag/AgCl photocatalysts show much higher photocatalytic activities than Ag/AgCl under visible light irradiation for methyl orange (MO) decomposition. Especially, the 2.0 wt% V5+‐doped Ag/AgCl photocatalyst shows the highest photocatalytic activity and also high stability after five cycles. The MO degradation rate during each cycle is almost maintained at 97%. Electron spin resonance spectroscopy and radical trapping experiments reveal that holes play an important role in the photocatalytic process. 相似文献
953.
954.
955.
In this article, we introduce two least‐squares finite element procedures for parabolic integro‐differential equations arising in the modeling of non‐Fickian flow in porous media. By selecting the least‐squares functional properly the presented procedure can be split into two independent subprocedures, one subprocedure is for the primitive unknown and the other is for the flux. The optimal order convergence analysis is established. Numerical examples are given to show the efficiency of the introduced schemes. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013 相似文献
956.
In this article, we disclose a method to fabricate polymer-stabilised azo-dye photo alignment layers for liquid crystal. The idea includes the introduction of polymer network in the alignment layer, in optimal concentration, followed by two-step irradiation. The stabilised photo-alignment layer has been explored for different aspects of the display-related parameters, viz. anchoring energy, stability for various display-related environments as a function of concentration of monomer and irradiation, residual DC and voltage holding ratio. The composite photo-alignment layer offers well-suited parameters for the liquid crystal alignment and therefore could find application in a variety of modern photonic and display devices. 相似文献
957.
A fluorine-containing polyacrylate emulsion was synthesized by a UV-initiated emulsion polymerization from methyl methacrylate (MMA) and hexafluorobutly methacrylate (HFMA) in the presence of 2-hydroxy-4-(2-hydroxyethoxy)-2-methyl-propiophenone (Irgacure 2959) as a hydrophilic photoinitiator at room temperature. The latex and films were characterized by Fourier transformed infrared (FT-IR) spectrometry, nuclear magnetic resonance (1H-NMR, 19F-NMR) spectrometry, transmission electron microscopy (TEM), recycling gel permeation chromatography (GPC), dynamic light scattering (DLS), and contact angle (CA) analysis, respectively. The effects of photoinitiator and emulsifier concentration on the polymerization were discussed. Compared to the corresponding thermal polymerization, UV-initiated polymerization of the MMA/HFMA emulsion could be accomplished at a much higher speed. The polymerization conversion in UV-initiated polymerization reached 95% within 10 min at an emulsifier concentration of 0.6 wt%, photoinitiator concentration of 0.4 wt%, and monomer concentration of 10 wt%. 相似文献
958.
Qian Wang Assoc. Prof. Fuhang Song Dr. Xue Xiao Pei Huang Assoc. Prof. Li Li Prof. Aaron Monte Dr. Wael M. Abdel‐Mageed Dr. Jian Wang Hui Guo Dr. Wenni He Feng Xie Dr. Huanqin Dai Miaomiao Liu Dr. Caixia Chen Hao Xu Assoc. Prof. Mei Liu Dr. Andrew M. Piggott Assoc. Prof. Xueting Liu Prof. Robert J. Capon Prof. Lixin Zhang 《Angewandte Chemie (International ed. in English)》2013,52(4):1231-1234
959.
Synthesis and characterization of intrinsic high‐barrier polyimide derived from a novel diamine monomer containing rigid planar moiety 下载免费PDF全文
Yi‐Wu Liu Jie Huang Jing‐Hua Tan Yi Zeng Qian Ding Xian‐Wei Xiang Yue‐Jun Liu Hai‐liang Zhang 《Journal of polymer science. Part A, Polymer chemistry》2017,55(14):2373-2382
A new diamine monomer containing rigid planar fluorenone moiety, 2,7‐bis(4‐aminophenyl)‐9H‐fluoren‐9‐one, was synthesized through Suzuki coupling reaction. Then it was reacted with pyromellitic dianhydride to obtain a polyimide (FOPPI) via a conventional two‐step polymerization process. The prepared FOPPI exhibits excellent barrier properties, with the oxygen transmission rate and water vapor transmission rate low to 3.2 cm3·m?2·day?1 and 2.9 g·m?2·day?1, respectively. The results of wide angle X‐ray diffractograms, positron annihilation lifetime spectroscopy, and molecular dynamics simulations reveal that the excellent barrier properties of FOPPI are mainly ascribed to the crystallinity, high chain rigidity, and low free volume, which are resulted from the rigid planar moiety. FOPPI also shows outstanding thermal stability and mechanical properties with a glass transition temperature up to 420 °C, 5% loss temperature of 607 °C, coefficient of thermal expansion of 1.28 ppm K?1, and tensile strength of 150.8 MPa. The polyimide has an attractive potential application prospect in the flexible electronics encapsulation area. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2373–2382 相似文献
960.
Shangjiang Guo 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2013,64(2):201-222
In this paper, we consider a neural network model consisting of three neurons with delayed self- and nearest-neighbor connections. We provide multiple bifurcations of the zero solution of the system near zero eigenvalue singularity. Taking the coupling coefficients as the bifurcation parameters, four kinds of zero singularities are demonstrated through center manifold reduction and normal form calculation. 相似文献