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Kun Gao Chang-Song Dai Jing Lv Xiang-Ming Feng 《Russian Journal of Electrochemistry》2014,50(3):267-273
To improve the electrochemical performance of Li2MnSiO4 with low electric conductivity, the Li2MnSiO4/C composite are synthesized by a vacuum solid-state reaction of a mixture of SiO2, LiCH3COO, Mn(CH3COO)2 and designed mass of C6H12O6 · H2O as carbon sources. The crystalline structure and morphology of products are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser scattering technology (LS) respectively. The tested results show that carbon doping decrease the crystallite sizes of products, but keep the aggregation of the particles and made the impurity increased instead. The results of constant current charge-discharge prove that the mixed carbon improve Li+ transmission performance and decrease inner polatization resistance of Li2MnSiO4 materials, but can not prevent the collapse of Li2MnSiO4 crystal structure. While the galvanostatic intermittent titration technique (GITT) results demonstrate that the primary reason for the improved electrochemical performance can be attributed to increased Li-ion diffusion coefficient $(D_{Li^ + } )$ as a result from carbon doping. 相似文献
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Exceedingly Fast Copper(II)‐Promoted ortho CH Trifluoromethylation of Arenes using TMSCF3 下载免费PDF全文
Ming Shang Shang‐Zheng Sun Dr. Hong‐Li Wang Dr. Brian N. Laforteza Prof. Dr. Hui‐Xiong Dai Prof. Dr. Jin‐Quan Yu 《Angewandte Chemie (International ed. in English)》2014,53(39):10439-10442
The direct ortho‐trifluoromethylation of arenes, including heteroarenes, with TMSCF3 has been accomplished by a copper(II)‐promoted C? H activation reaction which completes within 30 minutes. Mechanistic investigations are consistent with the involvement of C? H activation, rather than a simple electrophilic aromatic substitution (SEAr), as the key step. 相似文献
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Dr. Yitao Dai Dr. Corentin Poidevin Dr. Cristina Ochoa-Hernández Prof. Dr. Alexander A. Auer Priv.-Doz. Dr. Harun Tüysüz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(14):5837-5845
Direct selective oxidation of hydrocarbons to oxygenates by O2 is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C−H bonds at benzylic positions. In this work, stable, lead-free, Cs3Bi2Br9 halide perovskites are integrated within the pore channels of mesoporous SBA-15 silica and demonstrate their photocatalytic potentials for C−H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C5 to C16 including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol gcat−1 h−1 and excellent selectivity (>99 %) towards aldehydes and ketones under visible-light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well-dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp3)−H bond activation by photoinduced charges. 相似文献
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Prathibha Kumari Weiwei Liu Cheng-Jie Wang Jun Dai Mei-Xin Wang Qi-Qiong Yang Yu-Hua Deng Zhihui Shao 《中国化学》2020,38(2):151-157
Summary of main observation and conclusion A Pd-catalyzed asymmetric aromative[4+3]-cyclization reaction of amino-trimethylenemethanes(TMM,1d,ip3-oles)with fused 1-azadienes has been developed.This method enables access to the synthetically importance and biologically active benzofuran fused azepines and indeno-azepines in excellent efficiency and stereoselectivity(up to 95%yield,99%ee,>19:1 dr). 相似文献
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Nonlinear Dynamics - In this article, we analyze the $$L_{2}-L_{\infty }$$ filtering of multiagent systems for Markovian switch topologies under time-varying delays with an influence of... 相似文献
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研究蠕变加载条件下线黏弹性材料接触界面端附近的奇异应力场问题.考虑接触界面的摩擦,假设界面端的滑移方向不改变,相对滑移量微小,且其与位移同量级,由此线性化局部边界条件,根据对应原理得到Laplace变换域中的界面端应力场,导出时域中奇异应力场的卷积积分表达式.对卷积积分核函数进行数值反演,考虑接触材料的两类组合,一是持久模量具有量级上的差异,另一是持久模量接近相同.算例结果证实核函数可以用准弹性法求得的解析式较准确地近似.在此基础上,利用积分中值定理,并引入各应力分量的修正系数,得到黏弹性奇异应力场的简化式.结合核函数的数值反演结果分析修正系数表达式的取值范围,得到如下结论,若两相接触材料的持久模量相差很大,可以采用准弹性解的解析式较准确地描述界面端的奇异应力场;一般情况下,应力场不存在统一的奇异值和应力强度系数,当采用类似于准弹性解的表达式近似给出黏弹性应力场时,可以估计此近似描述的误差限.文中最后采用有限元分析黏弹性板端部嵌入部位的应力场,算例包括了黏弹性板与弹性金属支承、黏弹性板与黏弹性垫层所形成的滑移接触界面端,利用黏弹性有限元的数值结果验证理论分析所得结论的有效性. 相似文献
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[reaction: see text] A novel thiourea-based C2-symmetric ligand was synthesized, and its application in the palladium-catalyzed Heck and Suzuki coupling reactions of arenediazonium salts was evaluated. The reactions, which were performed at room temperature, without added base, and under aerobic conditions, produced product in 4 h with good yield. The corresponding arenediazonium salts were easily generated in one step from anilines. 相似文献