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2篇 您的检索式:作者名="Meixun Wen"
    题名 作者 年代 出处 被引量
1Discovery of native aluminum and its possible origin from prospective gas hydrate areas in the South China Sea显示文摘Aluminum is an active amphoteric metal element, but native aluminum (Al°) can be formed and preserved in special condi- tions so that its occurrence has unique geological significance. In this paper, the coarse fractions (> 63 μm) of 269 samples of surface sediments and of 165 sediment samples in four cores from the South China Sea (SCS) were picked out and analyzed. Al° particles were found in only five surface samples and three samples in two sedimentary cores. The particles are grayish or silver white in color with a strongly metallic luster and high plasticity, and they occur as irregular plats, elongated shapes and spherules with botryoidal structures. The identified Al° particles belong to cubical system, Fm3m space group with a varying from 4.028×10?1 nm to 4.059×10?1 nm. Their chemical compositions consist mainly of Al (95.07%–99.84%) and minor amounts of Si, Fe, Ti, S, Zn, Mg, Ca and trace amounts of K, Na, Cu, Co, P and Mn. Our results show that the identified Al° is authigenic, formed in situ in the prospective areas of gas hydrates, and that it is an unreported type of Al° occurrence. A possi- ble mechanism of Al° formation is proposed: under the strongly reducing micro environments at cold seeps, dissolved Al3+ in sediments is reduced to its metallic state by the strongly reducing agent of H2 through microbial processes and enzyme action. As a result, the Al° particles from the prospective gas hydrate areas in the SCS are the special products, representing the first report on Al° from the sediments at cold seeps. The proposed mechanism provides a theoretical basis for further studies on the special biogeochemical processes at cold seeps.CHEN Zhong HUANG ChiYue WU BiHao ZHAO MeiXun YAN Wen 2010Science China Earth Sciences2010,53,3:2
2Highly efficient acousto-optic modulation using nonsuspended thin-fil1m lithium niobate-chalcogenide hybrid waveguides显示文摘A highly efficient on-chip acousto-optic modulator is as a key component and occupies an exceptional position in microwave-to-optical conversion.Homogeneous thin-film lithium niobate is preferentially employed to build the suspended configuration for the acoustic resonant cavity,with the aim of improving the modulation efficiency of the device.However,the limited cavity length and complex fabrication recipe of the suspended prototype restrain further breakthroughs in modulation efficiency and impose challenges for waveguide fabrication.In this work,based on a nonsuspended thin-film lithium niobate-chalcogenide glass hybrid Mach-Zehnder interferometer waveguide platform,we propose and demonstrate a built-in push-pull acousto-optic modulator with a half-wave-voltage-length product VnL as low as 0.03 V cm that presents a modulation efficiency comparable to that of a state-of-the-art suspended counterpart.A microwave modulation link is demonstrated using our developed built-in push-pull acousto-optic modulator,which has the advantage of low power consumption.The nontrivial acousto-optic modulation performance benefits from the superior photoelastic property of the chalcogenide membrane and the completely bidirectional participation of the antisymmetric Rayleigh surface acoustic wave mode excited by the impedance-matched interdigital transducer,overcoming the issue of low modulation efficiency induced by the incoordinate energy attenuation of acoustic waves applied to the Mach-Zehnder interferometer with two arms in traditional push-pull acousto-optic modulators.Lei Wan Zhiqiang Yang Wenfeng Zhou Meixun Wen Tianhua Feng Siqing Zeng Dong Liu Huan Li Jingshun Ppan Ning Zhu Weiping Liu Zhaohui Li 2022Light(Science & Applications)2022,11,6:2
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