排序方式: 共有37条查询结果,搜索用时 15 毫秒
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Shilin Jiang Dr. Jianhui Lan Dr. Lin Wang Dr. Yalan Liu Yuke Zhong Yichuan Liu Dr. Liyong L.-Y. Yuan Dr. Lirong Zheng Prof. Zhifang Chai Prof. Weiqun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11721-11729
Molten salt electrolysis is a vital technique to produce high-purity lanthanide metals and alloys. However, the coordination environments of lanthanides in molten salts, which heavily affect the related redox potential and electrochemical properties, have not been well elucidated. Here, the competitive coordination of chloride and fluoride anions towards lanthanide cations (La3+ and Nd3+) is explored in molten LiCl-KCl-LiF-LnCl3 salts using electrochemical, spectroscopic, and computational approaches. Electrochemical analyses show that significant negative shifts in the reduction potential of Ln3+ occur when F− concentration increases, indicating that the F− anions interact with Ln3+ via substituting the coordinated Cl− anions, and confirm [LnClxFy]3−x−y (ymax=3) complexes are prevailing in molten salts. Spectroscopic and computational results on solution structures further reveal the competition between Cl− and F− anions, which leads to the formation of four distinct Ln(III) species: [LnCl6]3−, [LnCl5F]3−, [LnCl4F2]3− and [LnCl4F3]4−. Among them, the seven-coordinated [LnCl4F3]4− complex possesses a low-symmetry structure evidenced by the pattern change of Raman spectra. After comparing the polarizing power (Z/r) among different metal cations, it was concluded that Ln−F interaction is weaker than that between transition metal and F− ions. 相似文献
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Lou Yuke Ye Zhengmao Wang Shuxian Liu Shuxin Cheng Xin 《Journal of Thermal Analysis and Calorimetry》2019,135(4):2031-2038
Journal of Thermal Analysis and Calorimetry - Ettringite is an important cement hydration product and has a significant effect on cement performance. H-ettringite (synthesized by hydration... 相似文献
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电催化二氧化碳还原反应(E-CO2RR)可在温和条件下将CO2转化成高附加值燃料或化学品,近年来受到广泛关注,其在实际反应中涉及到气体扩散和多电子转移等复杂过程,构筑高效、稳定的催化电极是其发展的核心之一。然而,传统涂敷电极制备时,需要将催化剂与粘结剂混合涂覆于集流体表面,此过程会造成活性位点包埋和传质过程受限,致使催化剂活性位利用率下降,同时在反应过程中电极表面容易粉化,造成稳定性下降,难以重复利用。因此,如何调控电极反应界面,提升催化剂活性位的利用率仍面临挑战。将催化剂原位生长于集流体上得到的一体化电极可直接应用于电催化反应,不仅有利于提升活性位利用率以及电荷传输能力,还能有效调控三相界面处的微观反应环境(如pH、反应物及反应中间体的浓度等),从而实现电催化性能强化。本文综述了一体化电极用于E-CO2RR的最新进展,分析了结构和表界面调控对E-CO2RR性能的影响规律,并对该领域仍然存在的挑战和未来一体化E-CO2RR电极的发展进行了评述与展望。 相似文献
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关联分析理论在航空维修工程中的应用 总被引:3,自引:0,他引:3
文章利用灰色系统理论的关联度分析法较好地解决了航空维修质量评价这个问题。通过举例分析,证明了这种分析方法的可行性 相似文献
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He Xiaobo Li Yuke Zeng Hai Zhu Zengwei Tan Shiyong Zhang Yongjun Cao Chao Luo Yongkang 《中国科学:物理学 力学 天文学(英文版)》2023,66(3):1-10
Science China Physics, Mechanics & Astronomy - The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest and most sensitive single-dish radio telescope in the world and... 相似文献
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用系统工程学的观点, 重新认识矿山岩体工程的特点。建立矿山岩体工程稳定性的系统的概念。提出地质模型、设计模型、施工模型的构思, 使工程地质、设计、施工三者密切结合, 共同解决矿山岩体工程稳定问题。通过动态监测和信息反馈, 在工程施工的动态过程中不断地获得新的认识, 以便对工程实施做出新的决策。 相似文献
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岩体结构力学——岩体工程地质力学的新发展 总被引:2,自引:0,他引:2
本文从岩体工程地质力学角度, 研讨了岩体结构力学的意义, 地位与作用。作者就个人的认识, 将岩体结构力学的理论特点, 概括为五个方面, 即再变形和再破坏, 岩体结构的控制作用、岩体结构控制论、赋存环境以及关于岩体的多种力学介质和力学模型构成的力学体系。 相似文献
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The dielectric and elastic properties of liquid crystals (LCs) generally depend on the molecule structure, such as polar group and carbon chain length. For further investigation of the influence of molecular structure on the dielectric and elastic properties of fluorine-containing tricyclic isothiocyanate LC, the experimental temperature was controlled at 25°C by precision hot stage, and a precision LCR meter was used to measure the capacitance of six LC cells under the voltage from 0.1 to 20 V at 1 kHz. An LC cell capacitance model and a dual-cell model were adopted to obtain the dielectric anisotropy, and the capacitance–voltage curves of six LC materials were plotted. The threshold voltage of Fréedericksz transition was analysed, and a finite difference iterative method was used to attain specific values of three elastic constants. The influence of molecular structure on the dielectric and elastic constants was finally analysed. Experimental results showed that the introduction of meta-difluoro group would increase the dielectric anisotropy and reduce the threshold voltage of LC. As the length of the alkyl carbon chain increased, the dielectric anisotropy would have an odd–even alternation effect, which would lead to changes in the elastic constants of LC. 相似文献
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Kinran Lau Felix Niemann Dr. Kaltum Abdiaziz Dr. Markus Heidelmann Yuke Yang Dr. Yujin Tong Dr. Michael Fechtelkord Prof. Torsten C. Schmidt Dr. Alexander Schnegg Prof. R. Kramer Campen Dr. Baoxiang Peng Prof. Martin Muhler Dr. Sven Reichenberger Prof. Stephan Barcikowski 《Angewandte Chemie (International ed. in English)》2023,62(12):e202213968
Both oxygen vacancies and surface hydroxyls play a crucial role in catalysis. Yet, their relationship is not often explored. Herein, we prepare two series of TiO2 (rutile and P25) with increasing oxygen deficiency and Ti3+ concentration by pulsed laser defect engineering in liquid (PUDEL), and selectively quantify the acidic and basic surface OH by fluoride substitution. As indicated by EPR spectroscopy, the laser-generated Ti3+ exist near the surface of rutile, but appear to be deeper in the bulk for P25. Fluoride substitution shows that extra acidic bridging OH are selectively created on rutile, while the surface OH density remains constant for P25. These observations suggest near-surface Ti3+ are highly related to surface bridging OH, presumably the former increasing the electron density of the bridging oxygen to form more of the latter. We anticipate that fluoride substitution will enable better characterization of surface OH and its correlation with defects in metal oxides. 相似文献