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991.
将镍铁金属配位聚合物前驱体在惰性气氛下热分解制备了富氮洋葱碳(ONC)包覆的Ni/Ni Fe_2O_4多孔纳米棒复合析氧电催化剂,与Ni@ONC,Ni Fe_2O_4材料及传统Ru O_2催化剂相比,得益于这种富氮洋葱碳包覆的Ni/Ni Fe_2O_4一维多孔纳米异质结构,Ni/Ni Fe_2O_4@ONC材料拥有更优异的导电性能和更大的电化学活性面积(0.149 m F),因而表现出更优异的析氧电催化性能。Ni/Ni Fe_2O_4@ONC纳米棒在1 mol·L~(-1) KOH溶液中,10 m A·cm-2下的析氧过电位仅为299 m V,塔菲尔斜率为73 m V·dec-1,展现出优异的析氧稳定性能。 相似文献
992.
Anatase TiO2 surfaces, whether oxidised or hydroxylated, can be modified by nanoclusters of SnO and MgO to give a red shift in light absorption, enhanced charge separation and high reducibility. 相似文献
993.
Atif Ali Fan Cheng Wei-Hong Wen Xiao Ying Jaipal Kandhadi Hui Wang Hai-Yang Liu Chi-Kwong Chang 《中国化学快报》2018,29(12):1888-1892
A new bulky 2-chloro-5,10,15-tris(2,4,6-triphenylphenyl)-corrole was casually synthesized and the effect of mono-β-chlorination on its photophysical, electrochemical properties and light-induced singlet oxygen generation was investigated. 相似文献
994.
Vertical alignment (VA) is a widely applied operation mode for liquid crystal displays. To achieve optimum brightness, the electrode of VA is often patterned with fish-bone fine slits to generate fringe field, so the negative liquid crystal aligns along the fine slits when the electric field is applied. VA is usually simply modelled by the bend geometry along the cell gap. However, defects, domain boundaries and periodical splay induced by the fine slits also exist in real pixels and disturb the liquid crystal alignment. Polymer-stabilised VA test cells with various fine slit pitches which lead to various strength of fringe field were fabricated to observe the deformation of liquid crystal. Then the models of liquid crystal deformation nearby the defects and in the fine slit area were proposed to calculate the electromagnetic (fEM) and elastic free energy (felastic). The results show that the key factor to regulate fEM and felastic is the pitch of the fine slits, and the optimum liquid crystal alignment is obtained when fEM and felastic are equal. The models are useful for further investigation on the dynamics of liquid crystal alignment and applications in industrial products. 相似文献
995.
Qing-Ping Mei Yi-Ke Tang Tai-Fu Li Li-Zhong Yao Qiong Yang Heng-Jian Zhang 《Analytical letters》2018,51(8):1176-1193
The calibration model of near-infrared (NIR) spectra established using the Kalman filter-partial least square (partial least squares combined with a Kalman filter) method can be adapted to outdated equipment, environmental changes, external samples, and other applications. However, the variance of the measurement noise estimation for NIR spectrum measurements cannot be easily obtained using Kalman filter-partial least squares; therefore, the variance in the measurement noise is often assumed to be zero for the Kalman filter-partial least square calibration model, which affects the stability of the model. In this study, the measured input and output data were used effectively, and the gamma test method for estimating the measurement noise variance was used to improve the stability of the Kalman filter-partial least square calibration model. First, an accurate estimation of the measurement noise variance was obtained, and accurate modeling was then performed using Kalman filter-partial least squares. Finally, 600 abandoned drilling fluid samples were used to confirm the validity of the proposed method. The Kalman filter-partial least square and gamma test-Kalman filter-partial least square methods are compared. Testing of external samples 401–600 demonstrated that the stability of the Kalman filter-partial least square model decreased. The root mean square error of the prediction of the Kalman filter-partial least square model was 27.135, which was worse than that of the gamma test-Kalman filter-partial least square model (20.307). The validation results show that the proposed method has better stability in tracking the evolution of the NIR spectrometer’s measurement state. 相似文献
996.
《Electrophoresis》2018,39(4):626-634
Solid‐state nanopores are nanoscale channels through otherwise impermeable membranes. Single molecules or particles can be passed through electrolyte‐filled nanopores by, e.g. electrophoresis, and then detected through the resulting physical displacement of ions within the nanopore. Nanopore size, shape, and surface chemistry must be carefully controlled, and on extremely challenging <10 nm‐length scales. We previously developed a framework to characterize nanopores from the time‐dependent changes in their conductance as they are being formed through solution‐phase nanofabrication processes with the appeal of ease and accessibility. We revisited this simulation work, confirmed the suitability of the basic conductance equation using the results of time‐dependent experimental conductance measurements during nanopore fabrication by Yanagi et al., and then deliberately relaxed the model constraints to allow for (i) the presence of defects; and (ii) the formation of two small pores instead of one larger one. Our simulations demonstrated that the time‐dependent conductance formalism supports the detection and characterization of defects, as well as the determination of pore number, but with implementation performance depending on the measurement context and results. In some cases, the ability to discriminate numerically between the correct and incorrect nanopore profiles was slight, but with accompanying differences in candidate nanopore dimensions that could yield to post‐fabrication conductance profiling, or be used as convenient uncertainty bounds. Time‐dependent nanopore conductance thus offers insight into nanopore structure and function, even in the presence of fabrication defects. 相似文献
997.
Claudia A. Blindauer Rolf Griesser Antonín Holý Bert P. Operschall Astrid Sigel Bin Song 《Journal of Coordination Chemistry》2018,71(11-13):1910-1934
998.
Back Cover: Promoted Fixation of Molecular Nitrogen with Surface Oxygen Vacancies on Plasmon‐Enhanced TiO2 Photoelectrodes (Angew. Chem. Int. Ed. 19/2018) 下载免费PDF全文
999.
From Metal–Organic Frameworks to Single‐Atom Fe Implanted N‐doped Porous Carbons: Efficient Oxygen Reduction in Both Alkaline and Acidic Media 下载免费PDF全文
Long Jiao Gang Wan Rui Zhang Dr. Hua Zhou Prof. Dr. Shu‐Hong Yu Prof. Dr. Hai‐Long Jiang 《Angewandte Chemie (International ed. in English)》2018,57(28):8525-8529
It remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal–organic frameworks (MOFs) have been synthesized based on a novel mixed‐ligand strategy to afford high‐content (1.76 wt %) single‐atom (SA) iron‐implanted N‐doped porous carbon (FeSA‐N‐C) via pyrolysis. Thanks to the single‐atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized FeSA‐N‐C exhibits excellent oxygen reduction activity and stability, surpassing almost all non‐noble‐metal catalysts and state‐of‐the‐art Pt/C, in both alkaline and more challenging acidic media. More far‐reaching, this MOF‐based mixed‐ligand strategy opens a novel avenue to the precise fabrication of efficient single‐atom catalysts. 相似文献
1000.
Isolated Platinum Atoms Stabilized by Amorphous Tungstenic Acid: Metal–Support Interaction for Synergistic Oxygen Activation 下载免费PDF全文
Qian Zhang Xi‐Xi Qin Fan‐Peng Duan‐Mu Prof. Hui‐Ming Ji Prof. Zhu‐Rui Shen Dr. Xiao‐Peng Han Prof. Wen‐Bin Hu 《Angewandte Chemie (International ed. in English)》2018,57(30):9351-9356
Oxygen activation plays a crucial role in many important chemical reactions such as oxidation of organic compounds and oxygen reduction. For developing highly active materials for oxygen activation, herein, we report an atomically dispersed Pt on WO3 nanoplates stabilized by in situ formed amorphous H2WO4 out‐layer and the mechanism for activating molecular oxygen. Experimental and theoretical studies demonstrate that the isolated Pt atoms coordinated with oxygen atoms from [WO6] and water of H2WO4, consequently leading to optimized surface electronic configuration and strong metal–support interaction (SMSI). In exemplified reactions of butanone oxidation sensing and oxygen reduction, the atomic Pt/WO3 hybrid exhibits superior activity than those of Pt nanoclusters/WO3 and bare WO3 as well as enhanced long‐term durability. This work will provide insight into the origin of activity and stability for atomically dispersed materials, thus promoting the development of highly efficient and durable single atom‐based catalysts. 相似文献