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81.
水滑石(LDHs)是一种阴离子黏土材料,由于其主体层板厚度的可调性,使其在光/电催化、电池、超级电容器、传感器以及生物医药等领域都具有广泛应用。降低层厚至单层可使材料的物理化学性质发生根本改变,从而优化催化性能。近期研究表明,利用自上而下,自下而上的方法,可以实现单层LDHs类材料的合成,但是受限于产量(g级)以及成本设备等问题,目前规模化制备高质量单层LDHs类材料还没有工业案例。成核晶化隔离法是目前唯一规模化合成纳米LDHs的工业化方法,具有成本低,产量可吨级放大等优点。本综述从合成方法、表征手段、应用三个角度讨论了单层及超薄LDHs的精准调控,详细论述了近期关于单层及超薄LDHs合成突破以及LDHs的规模化生产进展,并对其性能进行了总结,为后续设计高性能单层LDHs提供思路。 相似文献
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Kai Wu Kang Li Sha Chen Ya‐Jun Hou Yu‐Lin Lu Jing‐Si Wang Mei‐Juan Wei Mei Pan Cheng‐Yong Su 《Angewandte Chemie (International ed. in English)》2020,59(7):2639-2643
A nanocage coupling effect from a redox RuII‐PdII metal–organic cage (MOC‐16) is demonstrated for efficient photochemical H2 production by virtue of redox–guest modulation of the photo‐induced electron transfer (PET) process. Through coupling with photoredox cycle of MOC‐16, tetrathiafulvalene (TTF) guests act as electron relay mediator to improve the overall electron transfer efficiency in the host–guest system in a long‐time scale, leading to significant promotion of visible‐light driven H2 evolution. By contrast, the presence of larger TTF‐derivatives in bulk solution without host–guest interactions results in interference with PET process of MOC‐16, leading to inefficient H2 evolution. Such interaction provides an example to understand the interplay between the redox‐active nanocage and guest for optimization of redox events and photocatalytic activities in a confined chemical nanoenvironment. 相似文献
84.
Chen Sun Ya‐Hui Guo Sha‐Sha Han Jing‐Zhao Li Kuan Jiang Lin‐Feng Dong Qi‐Long Liu Cheng‐Yang Yue Xiao‐Wu Lei 《Angewandte Chemie (International ed. in English)》2020,59(38):16465-16469
Considering the instability and low photoluminescence quantum yield (PLQY) of blue‐emitting perovskites, it is still challenging and attractive to construct single crystalline hybrid lead halides with highly stable and efficient blue light emission. Herein, by rationally introducing d10 transition metal into single lead halide as new structural building unit and optical emitting center, we prepared a bimetallic halide of [(NH4)2]CuPbBr5 with new type of three‐dimensional (3D) anionic framework. [(NH4)2]CuPbBr5 exhibits strong band‐edge blue emission (441 nm) with a high PLQY of 32 % upon excitation with UV light. Detailed photophysical studies indicate [(NH4)2]CuPbBr5 also displays broadband red light emissions derived from self‐trapped states. Furthermore, the 3D framework features high structural and optical stabilities at extreme environments during at least three years. To our best knowledge, this work represents the first 3D non‐perovskite bimetallic halide with highly efficient and stable blue light emission. 相似文献
85.
地铁荷载下饱和软黏土累积变形特性 总被引:5,自引:0,他引:5
针对地铁循环荷载作用下饱和软黏土的变形特性,对上海地铁2号线静安寺站附近的饱和淤泥质黏土进行(GDS)循环三轴试验,试验结果表明,振动次数一定时,累积塑性应变随动应力幅值的增大而增大,随荷载频率的增大而减小;采用正交设计法安排试验,充分考虑了振动次数、荷载频率、动应力幅值以及其两两交互作用等因素对土体累积变形的影响,结合数理统计分析法建立了影响土体变形的影响率及评价方法。研究结果显示,影响地铁隧道轴线变形的主要因素是动应力幅值,而荷载频率与振动次数的交互作用可以忽略,此研究成果对地铁隧道设计具有重要的参考价值。 相似文献
86.
The conversion efficiency of stimulated Raman scattering (SRS) in CH4 is studied by using a single longitudinal mode second-harmonic Nd:YAG laser (532 nm, linewidth 0.003 cm-1, pulse-width (FWHM) 6.5 ns).Due to the heat release from vibrationally excited particles, SRS processes often suffer from the thermal defocusing effect (TDE). In view of 6.5 ns laser pulse width is much shorter than the vibrational relaxation time of CH4 molecules, TDE can only affect the SRS processes afterwards. In the cases of low laser repetition, TDE will be not serious, because it will be removed by the thermal diffusion in Raman medium before the next pulse arrives. At the laser repetition rate 2 Hz, CH4 pressure 1.1 MPa and pump laser energy 95 m J, the quantum conversion efficiency of backward first-Stokes (BS1) has attained 73%. This represents the highest first-stokes conversion efficiency in CH4. Furthermore, due to the relaxation oscillation, the BS1pulses are narrowed to about 1.2 ns. As a result, the BS1 peak power turns out to be 2.7 times that of the pump. Its beam quality is also much better and is only slightly affected by TDE. This reason is that BS1 represents a wave-front-reversed replica of the pump beam, which can compensate the thermal distortions in Raman amplify process. Under the same conditions, but pump laser repetition rate as 10 Hz, the conversion efficiency of BS1 goes down to 36% due to TDE. From this study, we expect that a well-behaved 630 nm Raman laser may be designed by using a closed CH4/He circulating-cooling system, which may have some important applications. 相似文献
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采用长石、高岭土、石英为主要原料制备了分相液滴自清洁釉.利用扫描电镜、X射线衍射仪和显微镜接触角测量仪等测试仪器表征了样品性能.研究结果表明:当二氧化钛添加量为5wt;时,釉表面形成大量细小的孤立液滴,体积分数达58.48;,具有高的表面硬度(869.10 kg/mm2)和良好的亲水自清洁性(表面润湿角为13.361°).与现有的表面涂覆纳米涂料相比,该自清洁釉耐磨性强,制备方法简单,在中高温建筑陶瓷领域有着良好的应用前景,符合绿色环保理念. 相似文献
89.
设计并搭建了一套高精度的磁场测量和补偿系统,并结合中国科学院高能物理研究所(IHEP)的2K超导腔垂直测试平台对1.3 GHz单加速间隙超导腔的磁通排出效应开展了实验研究:利用研制的磁场测量和补偿系统能够精密地测量超导腔赤道位置磁场,并能够将磁场补偿至小于5.0×10-8 T;并对超导腔不同表面温度梯度下的磁通排出效应进行了测量分析;对钉扎了磁场的超导腔进行了射频性能测试,研究了超导腔电阻对磁通钉扎的敏感度,以及在不同电场梯度下超导腔的表面电阻变化情况。结果表明,研制的高精度磁场测量和补偿系统能够满足超导腔磁通排出研究的需求;高的超导腔表面温度梯度有利于磁通的排出;磁通钉扎电阻的敏感度随着加速电场梯度的增加而增大,导致超导腔的性能下降。此实验研究也为后续超导腔的研制奠定了一定基础。 相似文献
90.
Accurate correction of arbitrary spin fermion quantum tunneling from non-stationary Kerr-de Sitter black hole based on corrected Lorentz dispersion relation
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Bei Sha Zhi-E Liu Yu-Zhen Liu Xia Tan Jie Zhang Shu-Zheng Yang 《中国物理C(英文版)》2020,44(12):125104-125104-8
According to a corrected dispersion relation proposed in the study on the string theory and quantum gravity theory, the Rarita-Schwinger equation was precisely modified, which resulted in the Rarita-Schwinger-Hamilton-Jacobi equation. Using this equation, the characteristics of arbitrary spin fermion quantum tunneling radiation from non-stationary Kerr-de Sitter black holes were determined. A number of accurately corrected physical quantities, such as surface gravity, chemical potential, tunneling probability, and Hawking temperature, which describe the properties of black holes, were derived. This research has enriched the research methods and enabled increased precision in black hole physics research. 相似文献