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3篇 您的检索式:作者名="Ma Xuedan"
    题名 作者 年代 出处 被引量
1Influence ,of Processing Parameters on the Deformation Behavior of Ti14 Alloy Containing a Small Volume of Liquid显示文摘包含液体的小体积的 Ti14 合金的变丑行为上的处理参数的效果通过压缩测试被调查了。实验从 1000 ~ 1150 在变丑温度被进行吗?Chen Yongnan Wei Jianfeng Zhao Yongqing Ma Xuedan Hao Jianmin 2012稀有金属材料与工程2012,41,2:1
2Regulating off-centering distortion maximizes photoluminescence in halide perovskites显示文摘Metal halide perovskites possess unique atomic and electronic configurations that endow them with high defect tolerance and enable high-performance photovoltaics and optoelectronics.Perovskite light-emitting diodes have achieved an external quantum efficiency of over 20%.Despite tremendous progress,fundamental questions remain,such as how structural distortion affects the optical properties.Addressing their relationships is considerably challenging due to the scarcity of effective diagnostic tools during structural and property tuning as well as the limited tunability achievable by conventional methods.Here,using pressure and chemical methods to regulate the metal off-centering distortion,we demonstrate the giant tunability of photoluminescence(PL)in both the intensity(>20 times)and wavelength(>180 nm/GPa)in the highly distorted halide perovskites[CH_(3)NH_(3)GeI_(3),HC(NH_(2))2GeI_(3),and Cs Ge I_(3)].Using advanced in situ high-pressure probes and first-principles calculations,we quantitatively reveal a universal relationship whereby regulating the level of off-centering distortion towards 0.2 leads to the best PL performance in the halide perovskites.By applying this principle,intense PL can still be induced by substituting CH_(3)NH_(3)^(+)with Cs^(+)to control the distortion in(CH_(3)NH_(3))_(1-x)Cs_(x)GeI_(3),where the chemical substitution plays a similar role as external pressure.The compression of a fully substituted sample of CsGe I_(3)further tunes the distortion to the optimal value at 0.7 GPa,which maximizes the emission with a10-fold enhancement.This work not only demonstrates a quantitative relationship between structural distortion and PL property of the halide perovskites but also illustrates the use of knowledge gained from high-pressure research to achieve the desired properties by ambient methods.Xujie Lv Constantinos Stoumpos Qingyang Hu Xuedan Ma Dongzhou Zhang Songhao Guo Justin Hoffman Kejun Bu Xiaofeng Guo Yingqi Wang Cheng Ji Haijie Chen Hongwu Xu Quanxi Jia Wenge Yang Mercouri G.Kanatzidis Ho-Kwang Mao 2021National Science Review2021,8,9:1
3Preparation and characterization of SO_(4)^(2−)−/TiO_(2)and S_(2)O_(8)^(2)−/TiO_(2) catalysts显示文摘Nanosized solid superacids SO_(4)^(2−)/TiO_(2)and S_(2)O_(8)^(2)−/TiO_(2),as well as MCM-41-supported SO_(4)^(2−)/ZrO_(2),were prepared.Their structures,acidities,and catalytic activities were investigated and compared using XRD,N2 adsorption-desorption,and in situ FTIR-pyridine adsorption,as well as an evaluation reaction with pseudoionone cyclization.The results showed that SO_(4)^(2−)/TiO_(2)and S_(2)O_(8)^(2)−/TiO_(2)possess not only nanosized particles with diameters<7.0 nm,a BET sur-face greater than 140 cm2/g and relatively regular mesostruc-tures with pores around 4.0 nm,but also a pure anatase phase and strong acidity.Different from the Lewis acid nature of SO_(4)^(2−)/ZrO_(2)/MCM-41,SO_(4)^(2−)/TiO_(2)and S_(2)O_(8)^(2)−/TiO_(2)exhibit mainly Brønsted acidities.The strongest Brønsted acid sites were produced on SO_(4)^(2−)/TiO_(2)promoted with H2SO4,while Lewis acid sites on S_(2)O_(8)^(2)−/TiO_(2)even stronger than those on SO_(4)^(2−)/ZrO_(2)/MCM-41 were generated when persulfate solu-tion was used as sulfating agent.Because of their distinct acid natures,SO_(4)^(2−)/TiO_(2)and S_(2)O_(8)^(2)−/TiO_(2)exhibited catalytic activities for the cyclization of pseudoionone that were much higher than that of SO_(4)^(2−)/ZrO_(2)/MCM-41.It can be concluded that the existence of more Brønsted acid sites was favorable for proton participation in the cyclization reaction.MA Xuedan GUO Daishi JIANG Qizhong MA Zifeng MA Zhengfei YE Weidong LI Chunbo 2007Frontiers of Chemical Science and Engineering2007,1,1:0
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