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Terahertz bound states in the continuum with incident angle robustness induced by a dual period metagrating

Photonics Research 2022年第3期10卷 810-819页

作者： Wenqiao Shi Jianqiang Gu Xingyuan Zhang Quan Xu Jiaguang Han quanlong yang Longqing Cong Weili Zhang Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering Tianjin Universityand Key Laboratory of Optoelectronics Information and TechnologyMinistry of EducationTianjin 300072China Nonlinear Physics Centre Australian National UniversityCanberraACT 2601Australia Department of Electrical and Electronic Engineering Southern University of Science and TechnologyShenzhen 518055China School of Electrical and Computer Engineering Oklahoma State UniversityStillwaterOklahoma 74078USA

Metasurface-empowered bound state in the continuum(BIC)provides a unique route for fascinating functional devices with infinitely high quality factors.This method is particularly attractive to the terahertz community because it may essentially solve the deficiencies in terahertz filters,sensors,lasers,and nonlinear sources.However,most BIC metasurfaces are limited to specified incident angles that seriously dim their application prospects.Here,we propose that a dual-period dielectric metagrating can support multiple families of BICs that originate from guided mode resonances in the dielectric grating and exhibit infinite quality factors at arbitrarily tilted incidence.This robustness was analyzed based on the Bloch theory and verified at tilted incident angles.We also demonstrate that inducing geometric asymmetry is an efficient way to manipulate the leakage and coupling of these BICs,which can mimic the electromagnetically induced transparency(EIT)effect in our dual-period metagrating.In this demonstration,a slow-light effect with a measured group delay of 117 ps was achieved.The incidence-insensitive BICs proposed here may greatly extend the application scenarios of the BIC effect.The high Q factor and outstanding slow-light effect in the metagrating show exciting prospects in realizing high-performance filters,sensors,and modulators for prompting terahertz applications.

关键词： incident dielectric continuum

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Moiré-driven electromagnetic responses and magic angles in a sandwiched hyperbolic metasurface

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Photonics Research 2022年第9期10卷 2056-2065页

作者： YI LIU CHUNMEI OUyang QUAN XU XIAOQIANG SU quanlong yang JIAJUN MA YANFENG LI ZHEN TIAN JIANQIANG GU LIYUAN LIU JIAGUANG HAN YUNLONG SHI WEILI ZHANG Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering Key Laboratory of Optoelectronic Information Technology(Ministry of Education of China)Tianjin UniversityTianjin 300072China Institute of Solid State Physics College of Physics and Electronic ScienceShanxi Province Key Laboratory of Microstructure Electromagnetic Functional MaterialsShanxi Datong UniversityDatong 037009China Nonlinear Physics Centre Australian National UniversityCanberraACT 2601Australia School of Electrical and Computer Engineering Oklahoma State UniversityStillwaterOklahoma 74078USA

Recent moiréconfigurations provide a new platform for tunable and sensitive photonic responses,as their enhanced light–matter interactions originate from the relative displacement or rotation angle in a stacking bilayer or multilayer periodic array.However,previous findings are mostly focused on atomically thin condensed matter,with limitations on the fabrication of multilayer structures and the control of rotation angles.Structured microwave moiréconfigurations are still difficult to realize.Here,we design a novel moiréstructure,which presents unprecedented capability in the manipulation of light–matter interactions.Based on the effective medium theory and S-parameter retrieval process,the rotation matrix is introduced into the dispersion relation to analyze the underlying physical mechanism,where the permittivity tensor transforms from a diagonal matrix to a fully populated one,whereas the permeability tensor evolves from a unit matrix to a diagonal one and finally becomes fully filled,so that the electromagnetic responses change drastically as a result of stacking and rotation.Besides,the experiment and simulation results reveal hybridization of eigenmodes,drastic manipulation of surface states,and magic angle properties by controlling the mutual rotation angles between two isolated layers.Here,not only a more precisely controllable bilayer hyperbolic metasurface is introduced to moiréphysics,the findings also open up a new avenue to realize flat bands at arbitrary frequencies,which shows great potential in active engineering of surface waves and designing multifunctional plasmonic devices.

关键词： rotation hyperbolic diagonal

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Topology-empowered membrane devices for terahertz photonics

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Advanced Photonics 2022年第4期4卷 29-37页

作者： quanlong yang Dongyang Wang Sergey Kruk Mingkai Liu Ivan Kravchenko Jiaguang Han Yuri Kivshar Ilya Shadrivov Australian National University Nonlinear Physics CentreResearch School of PhysicsCanberra ActonAustralia Central South University School of Physics and ElectronicsChangshaChina The Hong Kong University of Science and Technology Department of PhysicsHong KongChina Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTennesseeUnited States Tianjin University Center for Terahertz Waves and College of Precision Instrument and Optoelectronics EngineeringTianjinChina

Control of terahertz waves offers a profound platform for next-generation sensing,imaging,and information communications.However,all conventional terahertz components and systems suffer from bulky design,sensitivity to imperfections,and transmission loss.We propose and experimentally demonstrate onchip integration and miniaturization of topological devices,which may address many existing drawbacks of the terahertz technology.We design and fabricate topological devices based on valley-Hall photonic structures that can be employed for various integrated components of on-chip terahertz systems.We demonstrate valleylocked asymmetric energy flow and mode conversion with topological waveguide,multiport couplers,wave division,and whispering gallery mode resonators.Our devices are based on topological membrane metasurfaces,which are of great importance for developing on-chip photonics and bring many features into terahertz technology.

关键词： topological devices terahertz photonics membrane on-chip

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大采高工作面压裂煤层开采工艺优化设计与研究

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山西化工 2024年第6期44卷 195-197页

作者：张全龙山西焦煤西山煤电斜沟煤矿山西吕梁033602

根据23101工作面大采高煤层硬度高,裂缝发育不完善,截割体积块度小的缺点,结合割煤形式和压裂煤层模型,建立压裂煤层数值模型,对不同煤层下切割深度、割落煤体的影响进行模拟仿真,基于现场实验数据表明:压裂后,工作面煤壁裂缝显著增加,... 详细信息

根据23101工作面大采高煤层硬度高,裂缝发育不完善,截割体积块度小的缺点,结合割煤形式和压裂煤层模型,建立压裂煤层数值模型,对不同煤层下切割深度、割落煤体的影响进行模拟仿真,基于现场实验数据表明:压裂后,工作面煤壁裂缝显著增加,每次切割的时间缩短了11.3%,牵引速度提升了12%,粉尘质量浓度减少了46%,同时,块煤率增加了19.7%。

关键词：大采高压裂煤层开采工艺

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Synergetic N-doped carbon with MoPd alloy for robust oxygen reduction reaction

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Nano Research 2023年第7期16卷 8996-9002页

作者： Chaojie Cen Wenjing Tang Tonghui Zhao Yun Song Yun yang quanlong Xu Wei Chen Zhejiang Key Laboratory of Carbon Materials College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China

Synergistic catalysis opens up a new venue to improve the comprehensive application of the catalyst.Herein,a composite catalyst(Mo-Pd@N-C)consisting of the N-doped carbon derived from pyrolysis of spherical polypyrrole and MoPd nanoparticles(NPs)was constructed to emphasize the strong metal-support interaction for robust oxygen reduction reaction(ORR).The enhanced anchoring between the MoPd NPs and the substrate,and the N-species formed on the carbon matrix make the Mo-Pd@N-C deliver excellent performance with a half-wave potential of 0.945 V(vs.reversible hydrogen electrode(RHE))for ORR,superior than that of commercial Pt/C(0.86 V).More importantly,it shows a negligible half-wave potential decline(<5 mV)and only~20%of mass activity(MA)attenuation after 30,000 cycles stability test,obviously better than those of Pt/C(~70%of MA attenuation and~30 mV of half-wave potential decline after only 15,000 cycles).This work highlights a novel synergistic method to prolong the life and improve the commercial prospects of the catalysts.

关键词： synergistic catalysis oxygen reduction reaction N-doped carbon MoPd alloy stability

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定量血流分数在冠状动脉心肌桥血流动力学评估中的应用价值

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中华心血管病杂志 2024年第2期52卷 165-171页

作者：王猛范兴满王全龙曹钰琨马晨越贺琼逸张海涛空军军医大学空军特色医学中心心内科北京100142 河北北方学院研究生院张家口075000 东部战区空军医院心内科南京210001 安徽医科大学第五临床学院合肥230032

目的探讨新一代定量血流分数(QFR)在心肌桥血流动力学评估中的应用价值以及初步探索形变定量血流分数(D-QFR)与QFR的相关性及相关因素。方法本研究为横断面研究。入选2012年6月至2022年6月于空军特色医学中心行冠状动脉造影检查提示单... 详细信息

目的探讨新一代定量血流分数(QFR)在心肌桥血流动力学评估中的应用价值以及初步探索形变定量血流分数(D-QFR)与QFR的相关性及相关因素。方法本研究为横断面研究。入选2012年6月至2022年6月于空军特色医学中心行冠状动脉造影检查提示单纯性心肌桥患者。采用定量冠状动脉造影测量心肌桥收缩期狭窄率及心肌桥长度。根据Nobel分级标准,将患者分为轻度狭窄组(收缩期狭窄率<50%)和中重度狭窄组(收缩期狭窄率≥50%),测量不同时相(包括收缩期和舒张期)3个位置(MCA入口前1~2 cm、MCA中间段、MCA出口后1~2 cm)的QFR数值,分别记作QFRa、QFRb、QFRc,并且记录加入血管形变信息分析的D-QFR值。将任一时相壁冠状动脉远端QFR≤0.8定义为QFR值异常。比较两组不同位置以及各组内不同位置、不同时相QFR值。采用多因素logistic回归分析QFR值异常的相关因素。采用Spearman秩相关分析D-QFR值与收缩期及舒张期QFR值的相关性。采用多元线性回归分析D-QFR的相关因素。结果共入选83例患者,其中男性58例,年龄(57.1±13.1)岁。轻度狭窄组48例,中重度狭窄组35例,两组收缩期及舒张期QFRb、QFRc值差异均有统计学意义(P均<0.05)。组内比较结果显示,QFRb、QFRc在收缩期的测值均低于舒张期;QFRb及QFRc均低于同期的QFRa(P均<0.05)。多因素logistic回归分析结果显示,心肌桥收缩期狭窄率(OR=1.225,95%CI 1.093~1.372,P<0.001)为QFR异常的相关因素。D-QFR值与收缩期及舒张期QFR值均呈正相关(相关系数分别为0.849、0.675,P均<0.001)。多元线性回归分析结果显示D-QFR值与年龄(β=-0.208,P=0.029)、收缩期狭窄率(β=-0.500,P<0.001)及心肌桥长度(β=-0.211,P=0.036)均呈负相关。结论心肌桥中远端的QFR值下降;心肌桥收缩期狭窄率为QFR值异常的重要相关因素。D-QFR与收缩期及舒张期QFR值均呈正相关;患者的年龄、收缩期狭窄率及心肌桥长度均是D-QFR值的相关因素。

关键词：心肌桥定量血流分数冠状动脉冠状动脉造影

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负载活性锰纤维材料的制备及其室温净化甲醛的性能研究

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环境科学学报 2024年第4期44卷 277-284页

作者：王晗菲谈小克高全龙刘娟倪春兰侯静涛华中农业大学资源与环境学院武汉430070

甲醛是室内环境中关注度最高的污染物之一,由于活性氧化锰对甲醛具有优异的室温净化性能,近年来受到了广泛关注.然而实验室合成的粉末活性锰通常难以直接应用,因此,如何制备低成本、环境友好的活性锰负载纤维材料仍然是阻碍其大面积推... 详细信息

甲醛是室内环境中关注度最高的污染物之一,由于活性氧化锰对甲醛具有优异的室温净化性能,近年来受到了广泛关注.然而实验室合成的粉末活性锰通常难以直接应用,因此,如何制备低成本、环境友好的活性锰负载纤维材料仍然是阻碍其大面积推广需要解决的重要难题.本研究采用涂布固定法,分别用乙烯基吡咯烷酮(PVP)和羧甲基纤维素钠(CMC)胶结剂进行负载,得到不同的活性锰负载纤维材料,同时运用XRD、SEM、Raman和FTIR等方法对负载材料的表面结构进行表征,评价了不同氧化锰负载纤维材料的室温净化甲醛性能及其影响因素.结果表明,胶结剂的类型、锰氧化物的性质及载体厚度等因素是影响其净化性能的关键因子.与CMC胶结剂相比,PVP胶结剂不仅使负载的活性锰粉末更多,同时其团聚现象也不明显,这主要归因于其较为温和的粘结能力.当使用厚度为J=80 g·cm^(-2)的纤维载体时,其负载量不仅高,且透气性良好,因而其甲醛净化性能较J=60 g·cm^(-2)和100 g·cm^(-2)载体好.CO程序升温结果表明,MnO_(2)-1样品的还原温度比MnO_(2)-2样品更低,因而具有更强的低温催化能力.通过优化制备条件,使用PVP胶结剂,将MnO_(2)-1负载到J=80 g·cm^(-2)厚度的纤维载体上,得到的活性锰负载纤维材料能快速将甲醛浓度从0.47 mg·m^(-3)降低至国家标准0.08 mg·m^(-3),获得比商品更为优异的净化性能.

关键词：氧化锰负载纤维材料净化甲醛胶结剂制备方法

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Low-dimensional MXenes as noble metal-free co-catalyst for solar-to-fuel production:Progress and prospects

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Journal of Materials Science & Technology 2022年第19期114卷 143-164页

作者： Wanying Lei Tong Zhou Xin Pang Shixiang Xue quanlong Xu College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key laboratory of Carbon Materials of Zhejiang Province Wenzhou UniversityWenzhou 325027China

Direct conversion of solar energy into chemical fuels via semiconducting materials through photocatalytic technology is a sustainable way to tackle the global warming, environmental issue and energy crisis. Transition metal carbides and nitrides(MXenes), a newly emerging class of 2D layered materials, has gained tremendous attention as a noble metal-free co-catalyst for boosting photoreactivity due to its extraordinary characteristics like elemental abundance, excellent electrical conductivity, abundant surface functional groups, unique hydrophilic behavior and flexible modulation of chemical composition. The rational integration of low-dimensional MXenes in the form of 2D layered structures or 0D quantum dots with diverse semiconducting materials offer more versatile and robust heterostructured-photocatalysts that are applicable in solar fuel generation. Herein, we summarize the recent advances and achievements in the synthesis of low-dimensional MXenes and their application in hydrogen production from water splitting and CO_(2) photoreduction. A comprehensive discussion of the fundamentals for solar fuel production, synthesis strategies and theoretical calculations for MXenes-based photocatalysts are also given. Finally, the existing challenges and further perspectives of MXenes-based nanostructures for efficient solar fuel production are addressed.

关键词： MXenes Low-dimensional materials Co-catalyst Photocatalytic H_(2)evolution CO_(2)photoreduction

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玉米发酵酱粉对植物肉品质及风味的改善作用研究

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食品科技 2024年第2期49卷 57-66页

作者：赵紫言范全龙杨海珍马仕宇王恒志曾祥权北京工商大学食品与健康学院中国轻工业植物基食品绿色低碳加工技术重点实验室北京市食品添加剂工程技术研究中心北京100048 宁夏伊品生物科技股份有限公司宁夏银川750100

玉米发酵酱粉是以玉米为主要原料,经特定菌种发酵制成的一种具有增鲜作用的调味基料。为探究玉米发酵酱粉对植物肉品质和风味的改善作用,以添加味精组为对照,通过感官评价、质构、色差、电子鼻、高效液相色谱和气相色谱质谱联用分析比... 详细信息

玉米发酵酱粉是以玉米为主要原料,经特定菌种发酵制成的一种具有增鲜作用的调味基料。为探究玉米发酵酱粉对植物肉品质和风味的改善作用,以添加味精组为对照,通过感官评价、质构、色差、电子鼻、高效液相色谱和气相色谱质谱联用分析比较两者对植物肉产品的影响。结果表明,玉米发酵酱组和味精组的样品感官评分与色度不存在显著差异,味精组植物肉的质构指标显著高于玉米发酵酱粉组。电子鼻的结果显示2组植物肉的风味能够被明显区分,而气相色谱质谱联用分析共检测出31种挥发性化合物,且玉米发酵酱粉组检测出的各类风味化合物含量均高于味精组。2组样品的醛类化合物含量均为最高,其中玉米发酵酱粉组为1776.2 ng/g,比味精组高5%。与添加味精相比,添加玉米发酵酱粉能够显著提升植物肉中酸类化合物和部分吡嗪类化合物(如吡嗪、2-甲基吡嗪、2-乙基-3,6-二甲基吡嗪)的含量。此外,高效液相色谱分析表明添加玉米发酵酱粉相比味精更能促进植物肉中某些鲜味和甜味氨基酸的含量提升。因此,玉米发酵酱粉具有独特的风味特性,可替代味精发挥对食品的风味改善作用,该研究结果可为玉米发酵酱粉的风味研究及在其他调味品的深层次应用提供理论支撑。

关键词：玉米发酵酱粉味精植物肉品质风味

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Construction of highly active WO_(3)/TpPa-1-COF S-scheme heterojunction toward photocatalytic H_(2)generation

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Journal of Materials Science & Technology 2022年第28期123卷 41-48页

作者： Long Sun Lingling Li Jiajie Fan quanlong Xu Dekun Ma School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325027China School of Materials and Energy Guangdong University of TechnologyGuangzhou 510006China Zhejiang Key Laboratory of Alternative Technologies for Fine Chemicals Process Shaoxing UniversityShaoxing 312000China

The rapid charge recombination and low surface reaction kinetics are the two major constraints to the photocatalytic performance of covalent organic frameworks(COFs).To accelerate the charge separation behavior,TpPa-1-COF is decorated with WO_(3)Bvia an in-situ growth approach,and the resultant WO_(3)/TpPa-1-COF composites show significantly improved photocatalytic performance.Especially,when the WO_(3)loading arrives at 3 wt%,3%WO_(3)/TpPa-1-COF exhibits the maximum photocatalytic H_(2)evolution rate of 19.89 mmol g^(-1)h^(-1),which is approximately 4.8 times higher than that of pure TpPa-1-COF.The apparent quantum efficiency(AQE)of 3%WO_(3)/TpPa-1-COF at 420 nm is detected to be 12.4%.X-ray photoelectron spectroscopy(XPS)characterization confirms the formation of internal electric field between WO_(3)and TpPa-1-CF,which can drive the photogenerated charge carrier diffusion in S-scheme mode.As a result,WO_(3)/TpPa-1-COF composite possesses high charge separation efficiency and strong redox ability,which is further supported by the photoelectrochemical results,thus benefiting the photocatalysis process.This work provides a rational strategy to modify COFs in photocatalytic water splitting.

关键词： Covalent organic framework(COF) WO_(3) S-scheme heterojunction Photocatalytic H_(2)evolution

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