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901.
902.
903.
Dong He Xianyin Song Wenqing Li Chongyang Tang Jiangchao Liu Zunjian Ke Changzhong Jiang Xiangheng Xiao 《Angewandte Chemie (International ed. in English)》2020,59(17):6929-6935
Despite the fact that many strategies have been developed to improve the efficiency of the oxygen evolution reaction (OER), the precise modulation of the surface electronic properties of catalysts to improve their catalytic activity is still challenging. Herein, we demonstrate that the surface active electron density of Co3O4 can be effectively regulated by an argon‐ion irradiation method. X‐ray photoelectron and synchrotron x‐ray absorption spectroscopy, UV photoelectron spectrometry, and DFT calculations show that the surface active electron density band center of Co3O4 has been upshifted, leading to a significantly enhanced absorption capability of the oxo group. The optimized Co3O4‐based catalysts exhibit an excellent overpotential of 260 mV at 10 mA cm?2 and Tafel slope of 54 mV dec?1, superior to the capability of the benchmark RuO2, representing one of the best Co‐based OER catalysts. This approach could guide the future rational design and discovery of ideal electrocatalysts. 相似文献
904.
Rui‐An Li Zhengyang Zhou Yu‐Kun Lian Fei Jia Xingxing Jiang Ming‐Cong Tang Li‐Ming Wu Junliang Sun Ling Chen 《Angewandte Chemie (International ed. in English)》2020,59(29):11861-11865
Structural modulations have been recently found to cause some unusual physical properties, such as superconductivity or charge density waves; however, thus‐induced nonlinear optical properties are rare. We report herein two unprecedented incommensurately modulated nonlinear optical sulfides exhibiting phase matching behavior, A2SnS5 (A=Ba, Sr), with the (3+1)D superspace groups P21212(00γ)00s or P21(α0γ)0, featuring different modulations of the [Sn2S7]∞ belts. Remarkably, Ba2SnS5 exhibits an excellent second harmonic generation (SHG) of 1.1 times that of the benchmark compound AgGaS2 at 1570 nm and a very large laser‐induced damage threshold (LIDT) of 8×AgGaS2. Theoretical studies revealed that the structural modulations increase the distortions of the Sn/S building units by about 44 or 25 % in A2SnS5 (A=Ba, Sr), respectively, and enhance significantly the SHG compared with α‐Ba2SnSe5 without modulation. Besides, despite the smaller Eg, the A2SnS5 samples exhibit higher LIDTs owing to their smaller thermal expansion anisotropies (Ba2SnS5 (1.51)<Sr2SnS5 (2.08)<AgGaS2 (2.97)). 相似文献
905.
Stéphane Hoang Dr. Simon Olivier Dr. Stéphane Cuenot Prof. Agnès Montillet Prof. Jérôme Bellettre Prof. Eléna Ishow 《Chemphyschem》2020,21(23):2502-2515
Highly concentrated dispersions of fluorescent organic nanoparticles (FONs), broadly used for optical tracking, bioimaging and drug delivery monitoring, are obtained using a newly designed micromixer chamber involving high impacting flows. Fine size tuning and narrow size distributions are easily obtained by varying independently the flow rates of the injected fluids and the concentration of the dye stock solution. The flash nanoprecipitation process employed herein is successfully applied to the fabrication of bicomposite FONs designed to allow energy transfer. Considerable enhancement of the emission signal of the energy acceptors is promoted and its origin is found to result from polarity rather than steric effects. Finally, we exploit the high spatial confinement encountered in FONs and their ability to encapsulate hydrophobic photosensitizers to induce photocrosslinking. An increase in the photocrosslinked FON stiffness is evidenced by measuring the elastic modulus at the nanoscale using atomic force microscopy. These results pave the way toward the straightforward fabrication of multifunctional and mechanically photoswitchable FONs, opening novel opportunities in sensing, multimodal imaging, and theranostics. 相似文献
906.
An alternative method for modulation of light generated by AlGaN/InGaN multiple quantum well laser with quartz antireflective (AR) coatings covering the resonator windows was modelled and studied theoretically. Disturbance of the piezoelectric coatings caused by surface acoustic waves (SAW) results in efficient intensity modulation of the laser beam. The model for the laser diode operating at DC demonstrates that the modulation factor can exceed 0.2 in sub-nanometer SAW displacement. For quarter-wave AR films, the carrier frequency of modulated beam has twice the frequency of SAW. 相似文献
907.
位相型全息记录介质的浮雕深度和折射率变化的测量方法 总被引:3,自引:0,他引:3
本文提出了一种直接测量位相型全息记录介质的浮雕深度和折射率改变量的方法,它利用干涉显微镜及带CCD摄像头的微机组成的简单系统,可获得很高的测量精度。本文分析了测量误差以及为使系统保持最高测量精度而应选取的最佳测量条件。 相似文献
908.
Linlin LI 《Chinese Journal of Lasers》1992,1(2):111-116
In this paper the frequency modulation characteristics the semiconductor laserwith weak optical feedback are presented,considering both the frequency deviation and thespurious intensity modulation.The frequency modulation can be realized without spurious in-tensity modulation under proper feedback conditions.There is an optimal feedback intensity tomaximize the frequency deviation. 相似文献
909.
910.
用智能波长校正的扫描式ICP光谱仪测定铬铁矿中六种元素成分 总被引:2,自引:1,他引:1
本文利用作者所在实研究室开发的扫描式ICP光谱仪的智能波长校正装置取代传统的ICP光谱仪的局部恒温系统,测定了铬铁矿及铬酸盐中的Cr,Si,Al,Fe,Mn和Mg六种元素成分。测定结果与铬矿标样的鉴定值基本一致,测量的相对标准偏差(RSD)为1.0%,智能波和工校正装置的波长校正结果与谱线峰值描迹结果的比较表明,该智能波长校正装置是有效的,具有省时,安全,结构简单的特点,有广泛的应用的前景。 相似文献