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31.
In this study, new chalcone compound 1 , new phthalonitrile derivatives 2 and 3, new copper(II), manganese(III) phthalocyanines bearing chalcone groups at peripheral or nonperipheral positions were synthesized. Electrochemistry of tetra-(4-{(2 E )-3-[2-fluoro-4-(trifluoromethyl)phenyl]prop-2-enoyl}phenoxy) substituted Co(II)Pc and Mn(III)Pcs were studied with cyclic voltammetry (CV) to determine the redox properties of the phthalocyanines. According to the results, while the CuPcs 2a and 3a showed two Pc based reduction reactions and one Pc based oxidation reaction, MnPcs 2b and 3b gave two metal-based reduction reactions. All the redox processes are shifted toward positive potentials as a result of the increased electron-withdrawing ability of the trifluoromethyl substituents. 相似文献
32.
Nonlinear Dynamics - This paper is concerned with the global regulation via output feedback for the time-delay nonlinear systems with unknown continuous output function and unknown growth rate.... 相似文献
33.
As the enantiomers of 1-phenylethanol are valuable intermediates in several industries, the lipase catalyzed kinetic resolution of (R,S) -1-phenylethanol is a relevant research topic. In this study, the goal was to determine the optimum reaction parameters to produce enantiomerically pure 1-phenylethanol by lipase (Novozyme 435) catalyzed kinetic resolution using response surface methodology (RSM). Reactions were performed with 40–400 mM (R,S)-1-phenylethanol, 120–1200 mM vinyl acetate and 2–22 mg/mL biocatalyst concentrations (BC L ), at 20–60 °C and with a stirring rate of 50–400 rpm for 5–120 min. The samples were analyzed using high performance liquid chromatography (HPLC) with a Chiralcel OB column. Optimum reaction parameters to reach 100% enantiomeric excess for the substrate ( ee s ) were determined as follows: substrate concentration (C s ): 240 mM, BC L : 11 mg/mL, at 42 °C with a reaction time of 75 min. Model validation was performed using these conditions and ee s was calculated as 100%, which indicates the predicted model was efficient and accurate. When compared to the literature, it was observed that the reaction time decreased significantly. This is an important result considering the industrial scale perspective. 相似文献
34.
Jiarui Yu Nan Gao Xiaowen Xie Xing Xin Zhanqi Li Shuai Chen Jingkun Xu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(5):794-802
Thermally healing capability of cracks and defects is important and urgent for the safe operation and life extending of electric materials and devices. Here, by the combination of thermally driven reversible Diels–Alder (DA) interaction and in-situ chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT), a series of intrinsically conductive poly(3,4-ethylenedioxythiophene) (PEDOT)/DA composites possess intrinsically self-healing property under low-temperature (reverse DA reaction at 100°C; DA crosslinking at 60°C) stimulus were achieved. The crosslinking DA bonding reactions are multiple from the co-existence of pre-synthesized macromolecular polyurethane attached DA units (PU-DA) and 2,4-hexadiyne-1,6-diol (DADOL) in the films. PU-DA involved in the polymerization process of EDOT to endow PEDOT with outstanding solution-processability, uniform film making, and structural self-healing capability, while DADOL was added to enhance the cross bonding between polymer chains. This work will accelerate the research and application development of intrinsically self-healing conducting polymers for commercial capacitors, antistatic coatings, implantable, printable electronics, and so on. 相似文献
35.
Dr. Xu Guo Xing Liu Prof. Junqing Yan Prof. Shengzhong Frank Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(69):e202202662
Solar-driven water splitting to produce clean and renewable hydrogen offers a green strategy to address the energy crisis and environmental pollution. Heterostructure catalysts are receiving increasing attention for photocatalytic hydrogen generation. ZnO/ZnS/CdS and ZnO/CdS heterostructures have been successfully designed and prepared according to two different strategies. By introducing a heterointerface layer of ZnS between ZnO and CdS, a Z scheme charge-transfer channel was promoted and achieved superior photocatalytic performance. A highest hydrogen generation rate of 156.7 μmol g−1 h−1 was achieved by precise control of the thickness of the heterointerface layer and of the CdS shell. These findings demonstrated that heterostructures are promising catalysts for solar-driven water splitting, and that heterointerface engineering is an effective way to improve the photocatalytic properties of heterostructures. 相似文献
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Shaobo Cheng Vidushi Sharma Altug S. Poyraz Lijun Wu Xing Li Amy C. Marschilok Esther S. Takeuchi Kenneth J. Takeuchi Marivi Fernndez-Serra Yimei Zhu 《Chemical science》2020,11(19):4991
Tunneled metal oxides such as α-Mn8O16 (hollandite) have proven to be compelling candidates for charge-storage materials in high-density batteries. In particular, the tunnels can support one-dimensional chains of K+ ions (which act as structure-stabilizing dopants) and H2O molecules, as these chains are favored by strong H-bonds and electrostatic interactions. In this work, we examine the role of water molecules in enhancing the stability of K+-doped α-Mn8O16 (cryptomelane). The combined experimental and theoretical analyses show that for high enough concentrations of water and tunnel-ions, H2O displaces K+ ions from their natural binding sites. This displacement becomes energetically favorable due to the formation of K2+ dimers, thereby modifying the stoichiometric charge of the system. These findings have potentially significant technological implications for the consideration of cryptomelane as a Li+/Na+ battery electrode. Our work establishes the functional role of water in altering the energetics and structural properties of cryptomelane, an observation that has frequently been overlooked in previous studies.Water displaces potassium ions and initiates the formation of a homonuclear dimer ion (K2+) in the tunnels of hollandite. 相似文献
39.
采用水热碳化法成功制备了不同碳含量的CdS@C纳米颗粒,同时对CdS@C的晶体结构、形貌、光学性能、光电化学和光催化性能进行了研究。实验结果表明本方法制备的碳包覆CdS纳米颗粒外壳为碳层,内核为六方纤锌矿结构CdS颗粒。CdS@C颗粒分散性良好,颗粒形貌主要为类球形,粒度均匀。X射线光电子能谱(XPS)证实CdS@C颗粒表面负载的碳主要以非晶碳形式存在。紫外-可见光光谱(UV-Vis)表明CdS@C纳米晶中表面碳的敏化作用提高了可见光响应范围,使得能隙变窄。光致发光光谱(PL)表明碳包覆CdS@C纳米颗粒的发光强度比纯CdS弱,有效抑制了光生载流子的复合。瞬态光电流响应和电化学阻抗谱(EIS)说明CdS@C纳米复合材料更有效促进电子-空穴对分离和提高转移效率。CdS@C纳米复合材料在可见光辐射下表现出良好的光催化活性和稳定性,其中·O2-和h+在光催化中起主要作用。 相似文献
40.
参照相关标准,对聚变装置真空室超压保护系统(VVPSS)中爆破片进行了选型。结合VVPSS的工作要求,完成了爆破片的设计计算,初步得到爆破片直径为882mm,厚度为1mm。利用有限元分析软件对多种型号爆破片进行结构分析比较,最终选用了反拱环向开缝型爆破片。对最终选定的爆破片进行优化设计,使其达到设计要求。 相似文献