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All-dielectric three-element transmissive Huygens’ metasurface performing anomalous refraction

Photonics Research 2019年第12期7卷 1501-1510页

作者： CHANG LIU LEI CHEN TIESHENG WU yumin LIU JING LI YU WANG ZHONGYUAN YU HAN ye LI YU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876 China2Guangxi Key Laboratory of Wireless Wideband Communication and Signal Processing Guilin 541004 China3College of Optical Sciences The University of ArizonaTucsonArizona 85721USA

Metasurfaces have pioneered a new avenue for advanced wave-front *** the various types of metasurfaces,Huygens'metasurfaces are thought to be a novel paradigm for flat optical *** by spectrally overlapped electric resonance and magnetic resonance,Huygens'metasurfaces are imparted with high transmission and full phase coverage of 2π,which makes them capable of realizing high-efficiency wave-front ***,a defect of Huygens'metasurfaces is that their phase profiles and transmissive responses are often sensitive to the interaction of neighboring Huygens'***,the original assigned phase distribution can be *** this work,we present our design strategy of transmissive Huygens'metasurfaces performing anomalous *** illustrate the investigation of Huygens'elements,realizing the overlapping between an electric dipole and magnetic dipole resonance based on cross-shaped *** find that the traditional discrete equidistant-phase design method is not enough to realize a transmissive Huygens'surface due to the interaction between neighboring Huygens'***,we introduce an extra optimization process on the element spacing to palliate the phase distortion resulting from the element *** on this method,we successfully design unequally spaced three-element transmissive metasurfaces exhibiting anomalous refraction *** anomalous refractive angle of the designed Huygens'metasurface is 30°,which exceeds the angles of most present transmissive Huygens'metasurfaces.A transmissive efficiency of 83.5%is numerically derived at the operating *** far-field electric distribution shows that about 93%of transmissive light is directed along the 30°refractive *** deflection angle can be tuned by adjusting the number of Huygens'elements in one metasurface unit *** design strategies used in this paper can be inspiring for other functional Huygens'metasurface schemes.

关键词： interaction. element refraction

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Experimental study of core and edge fluctuations by reflectometry on EAST tokamak

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Plasma Science and Technology 2021年第7期23卷 8-14页

作者： Zhen ZHOU Tao ZHANG Mingfu WU Kaixuan ye Fubin ZHONG Jia HUANG Kangning GENG Yukai LIU Gongshun LI Haoming XIANG yumin WANG Fei WEN Sanqiu LIU Jiangxi Province Key Laboratory of Fusion and Information Control Institute of Fusion Energy and Plasma ApplicationDepartment of PhysicsNanchang UniversityNanchang 330031People’s Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People’s Republic of China University of Science and Technology of China Hefei 230026People’s Republic of China Advanced Energy Research Center Shenzhen UniversityShenzhen 518060People’s Republic of China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 5180602People’s Republic of China

An eight-channel poloidal correlation reflectometer(PCR)with O-mode polarization has been installed in the EAST tokamak to measure the fluctuations from core to *** PCR launches eight different frequency microwaves(20.4,24.8,33,40,42.4,48,52.6,57.2 GHz)into the plasma from the low field side and two poloidally separated antennae are used to receive the reflected *** a result,the diagnostic can measure fluctuations in eight(radial)×two(poloidal)spatial *** diagnostic has been applied to study the core and edge pedestal fluctuations during an inter-ELM phase in H-mode *** inter-ELM phase can be divided into two *** the first stage,a low frequency(<50 kHz)broadband fluctuation dominates in the pedestal gradient *** the second stage,this fluctuation is strongly suppressed and quasi-coherent fluctuations(QCFs)*** QCF’s amplitude increases with the pedestal density gradient,implying density gradient driven *** the core fluctuations inside the pedestal show no evident changes during the inter-ELM phase.

关键词： core fluctuation edge fluctuation reflectometry

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Effect of the gain media on sub-Poissonian photon generation in quantum dot-metal nanoparticles hybrid system

Effect of the gain media on sub-Poissonian photon generation...

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第十八届全国量子光学学术会议

作者：王芋晶 Han ye Zhongyuan Yu yumin Liu Wenbin Xu 北京邮电大学 State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Science and Technology on Optical Radiation Laboratory

The effect of the gain media on sub-Poissonian photon generation in quantum dot-metal nanoparticles（QD-MNPs） hybrid system is theoretically demonstrated. The hybrid system with nanoscale footprint is built on the SiO2 substrate. We introduce gain media to reduce the dissipation of local surface plasmon by adjusting the gain coefficient. Compared with non-gain media system, the intensity of electric field near MNPs is far stronger when taking proper choice of gain coefficient, indicating that gain media helps to enhance the field intensity. The theoretical calculation indicates that gain media can improve quality factor of the MNPs by the dynamic feedback between them. Simulated by finite element method（FEM）, the Fano resonance is observed in the absorption cross section spectrum of the coupling system. Considering the MNPs as a single mode cavity, the system is investigated within the framework of cavity quantum electrodynamics by fitting eight parameters with FEM. The numerical results show that coupling between QD and MNPs falls in the strong coupling regime and the zero delay second-order autocorrelation function as low as 0.356 can be achieved with proper choice of gain coefficient, together with intra-cavity photon number N=0.07. Moreover, this system can generate sub-Poissonian photons in a large variation range of gain coefficient, and a certain degree of detuning between QD and cavity is allowed.

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High-efficiency all-dielectric transmission metasurface for linearly polarized light in the visible region

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Photonics Research 2018年第6期6卷 517-524页

作者： LIU YANG DONG WU yumin LIU CHANG LIU ZENGHUI XU HUI LI ZHONGYUAN YU LI YU RAN ye State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876 China School of Science Beijing University of Posts and Telecommunications Beijing 100876 China

We propose and numerically investigate an efficient transmission-mode metasurface that consists of quasi- continuous trapezoid-shaped crystalline silicon nanoantennas on a quartz substrate. This metasurface provides a linear phase gradient and realizes both full 2Jr phase shift and high transmission efficiency in the operating wavelength range from 740 to 780 nm. At the central wavelength around 751 nm, the total transmission efficiency is up to 88.0% and the section of the desired anomalous refraction is 80.4%. The anomalous refraction angle is 29.62°, and larger refraction angle can be achieved by changing the period of the super cell. We demonstrate a refraction angle as large as 38.59°, and the anomalous transmission efficiency reaches 76.6% at wavelength of 741 nm. It is worth mentioning that the structure is much simpler than conventional metasurfaces based on arrays of discrete nanoantennas. Our research may pave the way for designing efficient all-dielectric phase-gradient metasurfaces and applying them in integrated optical devices for wavefront control.

关键词： Metamaterials Phase shift Integrated optics devices

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Comparison of natural grassy ELM behavior in favorable/unfavorable Bt in EAST

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Plasma Science and Technology 2021年第9期23卷 49-59页

作者： Genfan DING Qingquan YANG Guosheng XU Xin LIN Yang ye Ran CHEN yumin WANG Qing ZANG Heng LAN Liang CHEN Zhikang LU Yifeng WANG Lingyi MENG Liang WANG Anhui University Hefei 230601People's Republic of China Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People's Republic of China University of Science and Technology of China Hefei 230026People's Republic of China Institute of Energy Hefei Comprehensive National Science CenterHefei 230031People's Republic of China

The properties of grassy edge-localized modes(ELMs)in EAST in the favorable and unfavorable Btare statistically *** analysis indicates that there is no systematical difference in the frequencies of grassy ELMs under the two different magnetic configurations in the similar parameter *** high-frequency grassy ELM(fELM>1 k Hz)in unfavorable Bt is dependent on the high poloidal betaβpand high triangularityδu,while the high-frequency grassy ELM(fELM>1k Hz)in favorable Btappears to rely on the high plasma density.A frequently occurring phenomenon in favorable Btdefined as‘clustered ELM’seems to be the most evident difference in ELM behavior between favorable and unfavorable *** analysis shows that larger plasma-wall outer gap,longer plasma elongation,lower low-hybrid wave heating power and electron cyclotron resonance heating power favor the occurrence of clustered grassy *** studies indicate that the generation of clustered grassy ELMs could be correlated with the lower electron temperature in the bulk plasma.

关键词： grassy ELM favorable and unfavorable Bt clustered ELM EAST

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Experimental study of double tearing mode on EAST tokamak

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Plasma Science and Technology 2020年第2期22卷 47-53页

作者： Mingfu WU Zixi LIU Tao ZHANG Fubin ZHONG Gongshun LI Haoming XIANG Kangning GENG Kaixuan ye Jia HUANG Fei WEN yumin WANG Xiang HAN Shoubiao ZHANG Haiqing LIU Guoqiang LI Ge ZHUANG Xiang GAO University of Science and Technology of China Hefei 230026People's Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China Advanced Energy Research Center Shenzhen UniversityShenzhen 518060People’s Republic of China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Optoelectronic EngineeringShenzhen UniversityShenzhen 518060People's Republic of China

The double tearing mode(DTM)in a high βN(βN>1.5)discharge with internal transport barrier on EAST was investigated.A 15 kHz tearing mode(TM)(m≥3,n=3)appears at outer q=2 surface at first,which is stable in the highβN *** a 2 kHz TM(m=2,n=1)occurs at inner q=2 *** after,high βN collapsed with the crash of ELM,and DTM formed during the collapse of β*** positions of the two islands of the DTM are consistent with the q=2 *** temperature fluctuations are the strongest between the two magnetic islands.A statistical analysis of high βN discharges operating with the reversed magnetic shear configuration in the EAST 2015-2018 campaign revealed the existence of the DTM in many *** the DTM phase,all βN are reduced by 10%-30% within 0.1 ***,there are two different βN behaviors thereafter-with and without βN *** the physical mechanism of βN recovery during the DTM phase will benefit steady-state operation with reversed shear configurations in the future.

关键词： highβN βN collapse EAST double tearing mode

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基于近场动力学数值方法的冰-吊舱推进器接触判断研究

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力学学报 2021年第5期53卷 1383-1401,I0003页

作者：徐佩王超郭春雨苏玉民叶礼裕哈尔滨工程大学船舶工程学院哈尔滨150001

吊舱推进器在极地船舶中的应用,可避免冰区航行中转向、调头困难等操纵问题,是极地船舶广泛采用的推进形式.在冰-吊舱推进器切削过程中,吊舱推进器受到了极端冰载荷的作用,对吊舱推进器结构强度和极地船舶的安全性带来严重的危害.为了... 详细信息

吊舱推进器在极地船舶中的应用,可避免冰区航行中转向、调头困难等操纵问题,是极地船舶广泛采用的推进形式.在冰-吊舱推进器切削过程中,吊舱推进器受到了极端冰载荷的作用,对吊舱推进器结构强度和极地船舶的安全性带来严重的危害.为了研究不同操纵状态的吊舱推进器与冰切削时冰载荷的变化规律,首先,详细介绍了近场动力学方法研究物体断裂问题的理论基础,分析该方法模拟冰材料的可行性.基于近场动力学方法和面元法耦合推导了适用于冰破碎问题模拟的材料破坏准则和冰载荷计算方法.其次,提出了不同操纵状态的吊舱推进器与冰的接触判断方法,建立了冰-吊舱推进器切削状态的数值计算模型,实现了冰-吊舱推进器切削动态变化过程的数值仿真.最后,分析了吊舱推进器在直航、斜航以及操舵状态与冰切削时冰块破碎、螺旋桨和桨叶冰载荷以及吊舱单元整体扭矩的变化情况.计算结果表明:本文提出的不同操纵状态的吊舱推进器与冰切削时的接触判断方法能够真实地模拟冰-吊舱推进器的切削过程,并能获得该过程中冰块的破坏现象和冰载荷变化特性,可为冰区海洋结构冰载荷数值预报技术的发展、冰区吊舱推进器结构的优化设计和运营提供指导.

关键词：冰吊舱推进器近场动力学方法接触判断方法冰载荷

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考虑源网荷关联戴维南等值的解析与辨识

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中国电机工程学报 2020年第9期40卷 2842-2853页

作者：叶平峰韩学山裴佑楠张玉敏电网智能化调度与控制教育部重点实验室(山东大学) 山东省济南市250061

针对黑箱式戴维南等值难以计及源网荷关联特性,使电压静态稳定性能提高的预防控制难以实施的问题。根据节点电压方程,将电力系统对戴维南等值节点电压影响解析分解为3个部分,即发电、负荷以及二者间耦合的关系,从而使其源网荷关联特性... 详细信息

针对黑箱式戴维南等值难以计及源网荷关联特性,使电压静态稳定性能提高的预防控制难以实施的问题。根据节点电压方程,将电力系统对戴维南等值节点电压影响解析分解为3个部分,即发电、负荷以及二者间耦合的关系,从而使其源网荷关联特性得到体现。在此基础上,根据戴维南等值电路,将等效电势和等效阻抗予以分解,给出相应的计及这一关联特性的戴维南等值电路,并依此提出基于补偿法的戴维南等值参数辨识方法。此方法在准确辨识节点戴维南等值参数的同时还能定量分析其他各节点变化特性对其参数构成的影响,是对戴维南等值由点到面的一种扩展。因此,其不仅能评估静态电压稳定的性能,而且也能成为给出预防控制实施策略的依据。IEEE 118节点系统算例仿真结果表明此方法的有效性,在广域量测环境下,有良好的工程应用前景。

关键词：电力系统源网荷戴维南等值电压稳定参数解析

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广州蓄能水电厂黑启动系统研究与设计

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水力发电 2010年第10期36卷 53-55页

作者：叶生彭煜民广州蓄能水电厂广东广州510950

阐述了黑启动系统对电网抵御风险、控制风险的重要性。研究了黑启动系统选址、主设备接线、控制流程等关键的设计技术问题。利用研究成果,成功建设了广州蓄能水电厂黑启动系统,使该厂具备了强大的黑启动能力。

关键词：黑启动系统研究设计广州蓄能水电厂

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The Analysis of Effective Factors in Piping Drinking Water in Beijing

The Analysis of Effective Factors in Piping Drinking Water i...

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2007中国科协年会

作者： Zhao Jinhui Du Hong Liu yumin Chen Binsheng Sheng Xin ye Yan Zheng Juan Beijing Center of Disease Control 100013

[Objective]To evaluate the effect of device of piping drinking water by surveying the changes of piping drinking water bstween the first used and period of time used.[Method]According to the relative standard of our country,piping drinking water is detected from 10 districts that are selected from previous data.[Result] There is significant difference between the first used and period of time used with hydrogen ion,turbidity,COD (P＜0.05).There is apparent significance from different cleansing principle with hydrogen ion,COD,rigidity (P＜0.05).There is no significance of different devices with time used in hydrogen ion,rigidity,COD, conductance and rigidity.(P＞0.05).[Conclusions]After a period of ruing of current piping drinking water device,the water qualifies of piping drinking water have no apparent ***,the possibility of secondary pollution still exists in the pipeline.

关键词： Piping drinking water Effective factors

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