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1 Gbps free-space deep-ultraviolet communications based on Ⅲ-nitride micro-LEDs emitting at 262 nm

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Photonics Research 2019年第7期7卷 19-25页

作者： Xiangyu He enyuan xie Mohamed Sufyan Islim Ardimas Andi Purwita Jonathan J.D.McKendry Erdan Gu Harald Haas Martin D.Dawson Institute of Photonics Department of PhysicsUniversity of StrathclydeGlasgow G11RDUK Li-Fi R&D Centre the University of EdinburghInstitute for Digital CommunicationsEdinburgh EH9 3JLUK

The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEDs with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.

关键词： communications Ⅲ-nitride micro-LEDs

10 Gbps wavelength division multiplexing using UV-A, UV-B, and UV-C micro-LEDs

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Photonics Research 2022年第2期10卷 516-523页

作者： Daniel M.Maclure Jonathan J.D.McKendry Mohamed Sufyan Islim enyuan xie Cheng Chen Xiaobin Sun Xudong Liang Xiaohui Huang Hanaa Abumarshoud Johannes Herrnsdorf Erdan Gu Harald Haas Martin D.Dawson Institute of Photonics Department of PhysicsSUPAUniversity of StrathclydeGlasgow G11RDUK LiFi Research and Development Centre Department of Electronic&Electrical EngineeringUniversity of StrathclydeTechnology&Innovation CentreGlasgow G11RDUK Fraunhofer Center of Applied Photonics Technology&Innovation CentreGlasgow G11RDUK Zhixin Semiconductor(Hangzhou)Co. Ltd.Hangzhou 311200China

Deep ultraviolet(DUV) optical wireless communications have seen increased interest in recent years due to the unique properties of light in this spectral region. However, the reported DUV data rates remain significantly lower than comparable demonstrations at visible wavelengths due to lower modulation bandwidths and/or output power of the sources. Here, we present a wavelength division multiplexing demonstration using three UV microlight-emitting diodes emitting at nominal peak wavelengths of 285, 317, and 375 nm, respectively, each with an emitting area of approximately 1369 μm^(2)(equivalent to circular device pixels of diameter;0 μm). Using orthogonal frequency division multiplexing, data rates of 4.17, 3.02, and 3.13 Gbps were achieved from the 285, 317, and 375 nm devices, respectively, for a combined data rate of 10.32 Gbps transmitted over a distance of 0.5 m.

关键词： Gbps multiplexing diodes

Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED

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Photonics Research 2017年第2期5卷 35-43页

作者： MOHAMED SUFYAN ISLIM RICARDO X.FERREIRA XIANGYU HE enyuan xie STEFAN VIDEV SHAUN VIOLA SCOTT WATSON NIKOLAOS BAMIEDAKIS RICHARD V.PENTY IAN H.WHITE ANTHONY E.KELLY ERDAN GU HARALD HAAS MARTIN D.DAWSON Li–Fi R&D Centre the University of Edinburgh Institute for Digital Communications Institute of Photonics Department of Physics University of Strathclyde Institute for Digital Communications Li–Fi R&D Centre the University of Edinburgh School of Engineering University of Glasgow Centre for Advanced Photonics and Electronics Electrical Engineering Division Department of Engineering University of Cambridge

Visible light communication(VLC)is a promising solution to the increasing demands for wireless *** nitride micro-sized light emitting diodes(micro-LEDs)are strong candidates for VLC due to their high *** violet micro-LEDs are reported in this work with electrical-to-optical bandwidths up to 655 *** orthogonal frequency division multiplexing-based VLC system with adaptive bit and energy loading is demonstrated,and a data transmission rate of 11.95 Gb/s is achieved with a violet micro-LED,when the nonlinear distortion of the micro-LED is the dominant noise source of the VLC system.A record 7.91 Gb/s data transmission rate is reported below the forward error correction threshold using a single pixel of the segmented array when all the noise sources of the VLC system are present.

关键词： Towards 10 Gb/s orthogonal frequency division multiplexing-based visible light communication using a GaN violet micro-LED VLC OFDM LEDs

Layered double hydroxides with atomic-scale defects for superior electrocatalysis

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Nano Research 2018年第9期11卷 4524-4534页

作者： Oixian xie Zhao Cai Pengsong Li Daojin Zhou Yongmin Bi Xuya Xiong enyuan Hu Yaping Li Yun Kuang Xiaoming Sun State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Department of Chemistry and Energy Sciences Institute Yale University West Haven Connecticut 06516 USA Chemistry Division Brookhaven National Laboratory Upzon New York 11973 USA College of Energy Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

Atomic composition tuning and defect engineering are effective strategies to enhance the catalytic performance of multicomponent catalysts by improving the synergetic effect; however, it remains challenging to dramatically tune the active sites on mulficomponent materials through simultaneous defect engineering at the atomic scale because of the similarities of the local environment. Herein, using the oxygen evolution reaction （OER） as a probe reaction, we deliberately introduced base-soluble Zn（II） or AI（III） sites into NiFe layered double hydroxides （LDHs）, which are one of the best OER catalysts. Then, the Zn（II） or AI（III） sites were selectively etched to create atomic M（I0/M（IIo defects, which dramatically enhanced the OER activity. At a current density of 20 ***-2, only 200 mV overpotential was required to generate M（II） defect-rich NiFe LDHs, which is the best NiFe-based OER catalyst reported to date. Density functional theory （DFT） calculations revealed that the creation of dangling Ni-Fe sites （i.e., unsaturated coordinated Ni-Fe sites） by defect engineering of a Ni-O-Fe site at the atomic scale efficiently lowers the Gibbs free energy of the oxygen evolution process. This defect engineering strategy provides new insights into catalysts at the atomic scale and should be beneficial for the design of a variety of catalysts.

关键词： selective defect engineering atomic vacancy layered double hydroxide electrocatalysis oxygen evolution reaction

贵州威宁地区沉积型稀土含矿岩系成因与富集规律

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地球科学 2021年第8期46卷 2711-2731页

作者：田恩源龚大兴赖杨邱小龙谢华田康志中国地质科学院矿产综合利用研究所四川成都610041 中国地质调查局稀土资源应用技术创新中心四川成都610041 贵州省地矿局113地质队贵州六盘水553000 四川省核工业地调院四川成都610052 成都理工大学沉积地质研究院四川成都610059

贵州威宁地区宣威组底部稀土含矿岩系的成因类型一直有较大争议.在野外实地调查的基础上,运用矿物学、岩相古地理与地球化学等手段进行了系统性研究.结果显示,区内二叠系宣威组底部稀土含矿岩系广泛分布,连续性好,含矿段厚度为2~16 m,... 详细信息

贵州威宁地区宣威组底部稀土含矿岩系的成因类型一直有较大争议.在野外实地调查的基础上,运用矿物学、岩相古地理与地球化学等手段进行了系统性研究.结果显示,区内二叠系宣威组底部稀土含矿岩系广泛分布,连续性好,含矿段厚度为2~16 m,并伴生有铌、锆、镓等元素;稀土氧化物平均品位0.15%,最高可达1.60%.主量、微量和稀土元素分析表明威宁地区稀土含矿岩系中含有来自玄武岩及火山灰的典型矿物,稀土配分模式与玄武岩相比具有继承性,研究区化学风化作用较强、成分成熟度较高代表其经过长距离搬运,遭受了改造;峨眉山玄武岩为该稀土层提供了主要物质来源,稀土层受源岩成分的控制,经历了沉积分选及再循环作用,还遭受了来自上地壳的中酸性岩浆物质源区的混染.其成因机制可能为在晚二叠世炎热、潮湿、强风化的环境中,玄武岩经过风化剥蚀后,搬运至沉积基底低洼处的三角洲平原亚相中的洪泛平原微相环境,与火山灰一同沉积沉淀,在风化和淋滤作用下稀土等元素以离子形式被解析出来,从而被吸附性强的高岭石等黏土矿物吸附于表面,或进入矿物晶格,形成富稀土层.

关键词：威宁稀土沉积型岩相古地理成矿模式成因机制

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劲性搅拌桩的试验研究

建筑结构学报 2001年第2期22卷 92-96页

作者：凌光容安海玉谢岱宗王恩远天津大学建筑设计研究院天津300072 沧州机械施工公司河北沧州061000 河北工业大学天津300130

本文提出的由水泥土和混凝土两种材料组成的劲性搅拌桩解决了搅拌桩强度、刚度不足的问题，使搅拌桩桩侧阻力得以充分发挥。通过第一批 24根原型桩系列对比试验，证实芯长和含芯率适当的劲性搅拌桩平均具有高于混凝土桩 30％以上的承载... 详细信息

本文提出的由水泥土和混凝土两种材料组成的劲性搅拌桩解决了搅拌桩强度、刚度不足的问题，使搅拌桩桩侧阻力得以充分发挥。通过第一批 24根原型桩系列对比试验，证实芯长和含芯率适当的劲性搅拌桩平均具有高于混凝土桩 30％以上的承载力，并初步掌握了劲性搅拌桩的载荷特性、工作机理和成桩工艺。

关键词：劲性搅拌桩水泥土搅拌桩芯桩试验载荷

石英岩峰后加卸载非线性断裂扩展及动态长度定量测定

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中国矿业大学学报 2024年第4期53卷 680-695页

作者：王笑然周鑫刘晓斐王恩元谢慧单天成刘舒欣中国矿业大学煤炭精细勘探与智能开发全国重点实验室江苏徐州221116 安徽理工大学煤炭安全精准开采国家地方联合工程研究中心安徽淮南232001 中国矿业大学安全工程学院江苏徐州221116

岩体工程灾害是围岩内部原生裂隙/节理起裂、发育到失稳破坏的演化结果,而灾害严重程度与峰后岩体断裂动态扩展特征密切相关.为了实现峰后阶段岩石非线性断裂扩展精准表征及裂纹长度动态定量测定,本文以含预制缺口的石英岩为对象,通过... 详细信息

岩体工程灾害是围岩内部原生裂隙/节理起裂、发育到失稳破坏的演化结果,而灾害严重程度与峰后岩体断裂动态扩展特征密切相关.为了实现峰后阶段岩石非线性断裂扩展精准表征及裂纹长度动态定量测定,本文以含预制缺口的石英岩为对象,通过夹式引伸计控制实现了石英岩三点弯曲I型断裂峰后阶段的准静态扩展,借助声发射(AE)和数字图像匹配(DIC)动态追踪了石英岩峰后循环加卸载断裂扩展全过程,提出了能耗展布-位移梯度-力学柔度相结合的非线性裂纹长度定量测定方法,并将动态测定结果与断裂力学理论模型进行了对比验证.结果表明:随着循环次数增加,裂纹张开位移-载荷(COD-P)和载荷点位移-载荷(LPD-P)曲线卸载斜率逐渐变缓柔度增加,裂纹逐渐向前扩展,试样承载能力逐渐下降;每次循环中,声发射在时间上集中出现在峰前损伤应力到峰后卸载点间,在空间分布集聚于裂纹的中上部区域,其定位坐标前端与DIC水平位移等值线交点相重合;在整个加卸载过程中,由AE能耗展布和DIC位移梯度法确定的裂纹长度相接近,其与基于COD-P和LPD-P曲线卸载柔度法反算的裂纹长度差值稳定在5.1 mm,该差值为石英岩断裂过程区(FPZ)长度;通过Dugdale-Barenblatt模型理论计算的石英岩FPZ长度为7.6 mm,其与声-图-力实测结果进行尺寸效应延伸获得无穷大尺寸FPZ渐进临界值吻合较好,验证了本文方法定量测定岩石非线性断裂扩展长度的可靠性,也表明了通过尺寸效应准则延伸来获取工程尺度岩体力学参数的重要性.

关键词： Ⅰ型断裂峰后加卸载声-图-力测量卸载柔度法断裂过程区尺寸效应

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Pr2O3掺杂对Mg-PSZ抗热震性能的影响

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陶瓷学报 2016年第3期37卷 245-248页

作者：王恩元谢建林李学钊上海材料研究所上海市工程材料应用评价重点实验室上海200080

本文研究了Pr_2O_3元素掺杂对氧化镁部分稳定氧化锆(Mg-PSZ)抗热震性能的影响,并从抗热震参数/抗热震损伤参数与相组成两方面解释了不同掺杂量对其抗热震性能的影响机理,结果表明:掺入Pr_2O_3导致Mg-PSZ的抗热震参数与抗热震损伤参数变... 详细信息

本文研究了Pr_2O_3元素掺杂对氧化镁部分稳定氧化锆(Mg-PSZ)抗热震性能的影响,并从抗热震参数/抗热震损伤参数与相组成两方面解释了不同掺杂量对其抗热震性能的影响机理,结果表明:掺入Pr_2O_3导致Mg-PSZ的抗热震参数与抗热震损伤参数变化且增加了单斜相的含量,细化晶粒使得Mg-PSZ的热震性能得到改善。

关键词：氧化镁部分稳定氧化锆 Pr2O3掺杂抗热震性能抗热震参数

碳热还原法合成ZrB_2粉体及其游离碳的去除

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耐火材料 2015年第6期49卷 435-437页

作者：王恩元谢建林李学钊上海材料研究所上海市工程材料应用评价重点实验室上海200080

以八水合氯氧化锆、硼酸、蔗糖、柠檬酸、甘油为原料,按n（C）n（Zr）分别为5.5 1、6 1、6.5 1、7 1、7.5 1配料,采用溶胶-凝胶法制成ZrB_2先驱体干凝胶,然后在1 500℃氩气气氛中碳热还原制备ZrB_2粉体。采用XRD、SEM分析ZrB_2粉体的物... 详细信息

以八水合氯氧化锆、硼酸、蔗糖、柠檬酸、甘油为原料,按n（C）n（Zr）分别为5.5 1、6 1、6.5 1、7 1、7.5 1配料,采用溶胶-凝胶法制成ZrB_2先驱体干凝胶,然后在1 500℃氩气气氛中碳热还原制备ZrB_2粉体。采用XRD、SEM分析ZrB_2粉体的物相组成和显微结构;采用DTA-TG分析ZrB_2粉体中游离碳和ZrB_2的起始氧化温度,然后分别在550和650℃进行0~140 min的除碳试验。结果表明：1）当配料中n（C）n（Zr）≤6.5时,ZrB_2粉体中不存在Zr C相;粉体团聚严重,一次颗粒粒径为100~200 nm,晶粒尺寸约为37 nm。2）ZrB_2粉体中游离碳和ZrB_2的起始氧化温度分别为500和700℃。3）在550和650℃分别氧化120和80 min后,游离碳已趋于氧化完全;在650℃保温140 min氧化后,ZrB_2未被氧化。

关键词：二硼化锆粉体溶胶-凝胶法碳热还原法游离碳