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Dynamically reconfigurable topological edge state in phase change photonic crystals

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Science Bulletin 2019年第12期64卷 814-822页

作者： tun Cao Linhan Fang Ying Cao Nan Li Zhiyou Fan Zhiguo Tao School of Optoelectronic Engineering and Instrumentation Science Dalian University of TechnologyDalian 116024China China North Vehicle Research Institute Beijing 100072China

The observation of topological edge states(TESs) revolutionized our understanding of scattering and propagation of electromagnetic(EM) waves. Supported by topological robustness, the TES at the interface between trivial and non-trivial insulators was not reflected from the structural disorders and imperfections. Recently topological photonic crystals(PhCs) were demonstrated to obtain remarkable one-way propagation of the TES, having the advantages of lossless propagation, dense integration, and high fabrication tolerance over conventional PhCs. Nevertheless, the lack of reversible switching of TES possesses significant limitations in helicity/spin filtering and tunable photonic devices. We proposed a topological PhC based on a prototypical phase-change material, Ge2 Sb2 Te5(GST225) to solve the problem. We find that at a particular frequency, the TES within the structure can be reversibly switched between "on"and "off" by transiting the GST225 structural state between amorphous and crystalline. Moreover, the topology of the PhC was maintained since the tuning of TES was achieved by varying the refractive index of GST225 instead of the structural geometry. This provides a continuous change of the spectral position of the photonic bandgap and TES by gradually crystallising the GST225. We show that the phase change of GST225 from amorphous to crystalline and vice versa can be engineered in nanoseconds. Our proof of concept may offer a platform for dynamically tuning the TESs that might otherwise be challenging to attain in photonic systems. We expect it to have potential applications for photonic devices in topological optical circuits and scatter-free one-way light propagation.

关键词： Phase change materials Photonic crystals Topological edge states tunability Reconfigurability

Myanmar-India Trade Relations Since 1988

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Myanmar-India Trade Relations Since 1988

作者： Nay Lin tun 华中师范大学

学位级别：硕士

1988年印度成为缅甸主要的出口市场之一以来,缅印两国在经济合作和技术进步领域的贸易关系蓬勃发展。缅甸主要向印度出口柚木、硬木、豆类和大米,而从印度进口的商品包括机械、纺织、纱线和钢铁。对印度来说,缅甸扮演着十分重要的角色:... 详细信息

1988年印度成为缅甸主要的出口市场之一以来,缅印两国在经济合作和技术进步领域的贸易关系蓬勃发展。缅甸主要向印度出口柚木、硬木、豆类和大米,而从印度进口的商品包括机械、纺织、纱线和钢铁。对印度来说,缅甸扮演着十分重要的角色:它是东南亚的“门户”,也是东盟的一员,与印度拥有共同的陆地边界和海洋边界。1991年,印度总理雷欧(Narasimha Rao)采取“东望”政策,两国关系得到进一步发展,并为开展边境贸易提供了有利条件。2011年之后,两国贸易关系明显著增强,印度占缅甸出口总额的四分之一。缅甸和印度拥有正常的贸易关系,为逐步发展两国常规贸易和边境贸易做出了有益贡献。本研究旨在找出贸易关系对两国至关重要的原因所在。本文采用了定性和定量文献分析方法。二手资料中使用的大多数数据来自于学术文章、期刊、政府信息和报纸。与此同时,本文还使用了通过正式访而谈得到的一手数据。2014年,印度现任总理莫迪(Narendra Modi)将“东望政策”升级为“东进政策”。印度东北部地区与缅甸相连,为促进该地区经济发展,印度采取了“东望政策”。这也是为什么印缅两国经济迅速发展的原因所在。印度和缅甸的贸易关系取决于两国双边边境贸易的增长。这项政策中,印度正加大投资,从而改善与缅甸和东南亚地区其他国家的实物交换、制度交流和人文交流。印度一直在为加强与缅甸的经贸关系而努力,其中包括印度-缅甸-泰国三边公路项目和卡拉丹多模式联运项目。本研究将验证这些联通工程是否会促进缅甸与印度之间的贸易。本文探讨了影响缅印两国度边境贸易的关键性因素。事实证明,两国的贸易政策变化极为重要。随后本文分析了印度“东进政策”对缅印度贸易关系的影响。本文提到,印度的“东进政策”改善了两国的双边贸易,促进了多边倡议。但与此同时,因为基础设施不完善、道路连接工程延期以及边界安全问题,双边贸易关系也面临严峻考验。但是,两国的贸易关系将促进边境检查站的发展,加强两国的关系。综上所述,本研究发现,两国的双边贸易关系,为两国带来了挑战,也带来了新的发展机遇。

关键词：缅甸印度贸易关系边境贸易东进政策

Wideband mid-infrared thermal emitter based on stacked nanocavity metasurfaces

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International Journal of Extreme Manufacturing 2022年第1期4卷 133-141页

作者： tun Cao Meng Lian Kuan Liu Xianchao Lou Yaoming Guo Dongming Guo School of Optoelectronic Engineering and Instrumentation Science Dalian University of TechnologyDalianPeople’s Republic of China Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalianPeople’s Republic of China

Efficient thermal radiation in the mid-infrared(M-IR)region is of supreme importance for many applications including thermal imaging and sensing,thermal infrared light sources,infrared spectroscopy,emissivity coatings,and *** ability to control light makes metasurfaces an attractive platform for infrared ***,different metamaterials have been proposed to achieve high thermal *** date,broadening the radiation bandwidth of a metasurface emitter(meta-emitter)has become a key goal to enable extensive *** experimentally demonstrate a broadband M-IR thermal emitter using stacked nanocavity metasurface consisting of two pairs of circular-shaped dielectric(Si;N;)–metal(Au)stacks.A high thermal radiation can be obtained by engineering the geometry of nanocavity *** a meta-emitter provides wideband and broad angular absorptance of both p-and s-polarized light,offering a wideband thermal radiation with an average emissivity of more than 80%in the M-IR atmospheric window of 8–14μ*** experimental illustration together with the theoretical framework establishes a basis for designing broadband thermal emitters,which,as anticipated,will initiate a promising avenue to M-IR sources.

关键词： mid-infrared wideband perfect thermal radiation surface plasmon resonance metasurface nanocavity

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关于太阳能电池若干问题的讨论

大学物理 2024年第5期43卷 25-28页

作者：张智明何珊孙铁囤广东理工学院大学物理实验中心智能制造学院广东肇庆526100 华南师范大学信息光电子科技学院广东广州510006 常州亿晶光电科技股份有限公司江苏常州213213

本文探讨了太阳能电池研究和教学中的3个问题:太阳能电池的核心是一个PN结,但为什么太阳能电池的伏安特性曲线与普通PN结的伏安特性曲线看起来相差甚远?太阳能电池的伏安特性曲线的变化细节到底是怎么样的?太阳能电池电路的输出电流、... 详细信息

本文探讨了太阳能电池研究和教学中的3个问题:太阳能电池的核心是一个PN结,但为什么太阳能电池的伏安特性曲线与普通PN结的伏安特性曲线看起来相差甚远?太阳能电池的伏安特性曲线的变化细节到底是怎么样的?太阳能电池电路的输出电流、输出电压及输出功率是怎样随负载电阻变化的?本文的研究结果表明:太阳能电池的伏安特性曲线与普通PN结的伏安特性曲线之所以看起来相差甚远,是因为它本质上是太阳能电池电路负载电阻的伏安特性曲线,而不是太阳能电池中PN结的伏安特性曲线;在太阳能电池的伏安特性曲线中,随着电压的增大,电流是单调减小的;对确定的太阳能电池电路,随着负载电阻的增大,输出电流单调减小,输出电压单调增大,但输出功率不是单调变化的,而存在一个最佳功率值,这个最佳功率值对应一个最佳负载电阻值.

关键词：太阳能电池伏安特性曲线负载特性曲线

人体成分与跟骨骨密度因果关联:一项孟德尔随机化研究

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山西医科大学学报 2024年第8期55卷 1055-1061页

作者：宋继东刘暾张心毅赵家鑫王伟西安交通大学第二附属医院骨科西安710003

目的采用孟德尔随机化方法研究人体成分与跟骨骨密度的因果关系。方法利用全基因关联分析数据,暴露因素为全身脂肪量、全身水分量和去脂体质量,结局变量为跟骨骨密度。采用IVW法、MR-Egger法、加权中位数法、简单模式法、加权模式法进... 详细信息

目的采用孟德尔随机化方法研究人体成分与跟骨骨密度的因果关系。方法利用全基因关联分析数据,暴露因素为全身脂肪量、全身水分量和去脂体质量,结局变量为跟骨骨密度。采用IVW法、MR-Egger法、加权中位数法、简单模式法、加权模式法进行孟德尔随机化分析,并行异质性、敏感性、多效性分析以检验结果可靠性。结果IVW法显示全身脂肪量与跟骨骨密度存在正向因果关系(β=1.10,95%CI 1.05~1.15,P0.05);IVW法显示去脂体质量与跟骨骨密度之间因果关系无统计学意义(β=0.97,95%CI 0.91~1.03,P>0.05)。结论人体全身脂肪量与跟骨骨密度存在正向因果关系。

关键词：人体成分骨质疏松全身脂肪量跟骨骨密度孟德尔随机化全基因组关联分析

Subtalar arthroscopy:When,why and how

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World Journal of Orthopedics 2015年第1期6卷 56-61页

作者： tun Hing Lui Sheung Chi Tong Department of Orthopaedics and Traumatology North District Hospital Department of Orthopaedics and Traumatology United Christian Hospital

Technique of subtalar arthroscopy is rapidly evolving. Increasing number of traditional open procedures for the subtalar joint can now be done arthroscopically. It is hoped that less wound complications, faster rehabi... 详细信息

关键词： Subtalar arthroscopy Subtalar stiffness Arthrodesis Calcaneofibular impingement Tarsal canal

Bovine Serum Albumin-Conjugated Ferrimagnetic Iron Oxide Nanoparticles to Enhance the Biocompatibility and Magnetic Hyperthermia Performance

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Nano-Micro Letters 2016年第1期8卷 80-93页

作者： Viveka Kalidasan Xiao Li Liu tun Seng Herng Yong Yang Jun Ding Department of Materials Science and Engineering Faculty of Engineering National University of Singapore Shaanxi Key Laboratory of Degradable Biomedical Materials School of Chemical Engineering Northwest University

Magnetic hyperthermia is a fast emerging, non-invasive cancer treatment method which is used synergistically with the existing cancer therapeutics. We have attempted to address the current challenges in clinical magnetic hyperthermia-improved biocompatibility and enhanced heating characteristics, through a single combinatorial approach. Both superparamagnetic iron oxide nanoparticles(SPIONs) of size 10 nm and ferrimagnetic iron oxide nanoparticles(FIONs) of size 30 nm were synthesized by thermal decomposition method for comparison studies. Two different surface modifying agents, viz, Cetyl Trimethyl Ammonium Bromide and 3-Aminopropyltrimethoxysilane, were used to conjugate Bovine Serum Albumin(BSA) over the iron oxide nanoparticles via two different methods—surface charge adsorption and covalent amide bonding, respectively. The preliminary haemolysis and cell viability experiments show that BSA conjugation mitigates the haemolytic effect of the iron oxide nanoparticles on erythrocytes and is non-cytotoxic to the healthy Baby Hamster Kidney cells. It was observed from the results that due to better colloidal stability, the SAR value of the BSA-iron oxide nanoparticles is higher than the iron oxide nanoparticles without BSA, irrespective of the size of the iron oxide nanoparticles and method of conjugation. The BSA-FIONs seem to show improved biocompatibility, as the haemolytic index is less than 2 % and cell viability is up to 120 %, when normalized with the control. The SAR value of BSAFIONs is 2300 Wg^(-1) when compared to 1700 Wg^(-1) of FIONs without BSA conjugation. Thus, we report here that BSA conjugation over FIONs(with a high saturation magnetization of 87 emug^(-1)) provide a single combinatorial approach to improve the biocompatibility and enhance the SAR value for magnetic hyperthermia, thus addressing both the current challenges of the same.

关键词： Magnetic hyperthermia Ferrimagnetic iron oxide nanoparticles Bovine serum albumin Haemolysis Cell viability Specific absorption rate

乡村振兴背景下冀南地区乡村文化创新与品牌传播

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管理工程师 2024年第5期29卷 37-40,80页

作者：周燕双董暾侯轲卢志翠邯郸学院夏青传媒学院河北邯郸056005 邯郸学院软件学院河北邯郸056005

乡村振兴战略是当前一项重要国家战略。在这个背景下,乡村文化的挖掘和传播也成为重要议题。以冀南地区为例,探讨乡村文化创新与品牌传播的重要性和现状,并提出了相应的解决方案和策略。通过对当地乡村文化的挖掘和传播,可以提高当地农... 详细信息

乡村振兴战略是当前一项重要国家战略。在这个背景下,乡村文化的挖掘和传播也成为重要议题。以冀南地区为例,探讨乡村文化创新与品牌传播的重要性和现状,并提出了相应的解决方案和策略。通过对当地乡村文化的挖掘和传播,可以提高当地农民的文化自信和地方认同感,促进乡村经济的发展,实现乡村振兴的目标。

关键词：乡村振兴冀南地区乡村文化品牌传播

Novel Terpyridine-bridged Parallel Dication Metallo-bisviologens and Their Supramolecular Complexes

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Chemical Research in Chinese Universities 2019年第2期35卷 229-234页

作者： LIU Qianqian GUO Yuan WU tun CHEN Mingzhao XIE Tingzheng WANG Pingshan Department of Organic and Polymer Chemistry College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083P.R.China Key Laboratory for Water Quality and Conservation of the Pearl River Delta Ministry of EducationInstitute of Environmental Research at Greater BayGuangzhou UniversityGuangzhou 510006P.R.China

By utilizing terpyridine-bridged parallel metallo-complexes as dication metallo-bisviologens,herein we present the synthesis and characterization of two novel supramolecular complexes.1-Methylpyridin-1-ium-terpyridine ligands and their metallo-complexes were first designed and synthesized,and the association of methyl-pyridiniums with dibenzo-24-crawn-8 ether(DB24C8)afforded the desired novel complexes through host-guest *** self-assembly behavior of the supramolecular complexes was comprehensively investigated and could be exploited for furtlaer construction of ID to 3D supramolecular infrastructures.

关键词： Supramolecular complex Host-guest interaction Metallo-viologen Dibenzo-24-croyvn-8 ether Terpyridine