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Dual-polarization two-dimensional valley photonic crystals

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Science China(Physics,Mechanics & Astronomy) 2022年第8期65卷 102-109页

作者： Xin-Tao He jian-Wei Liu Fu-Long Shi Ke Shen wen-Jie Chen Xiao-dong Chen jian-wen dong School of Physics State Key Laboratory of Optoelectronic Materials and TechnologiesSun Yat-sen UniversityGuangzhou510275China

The recent realization of valley physics in photonic systems has enriched the topological phases of light with protected edge modes and shown applications in designing high-performance photonic devices. However, the widely reported valley Hall effect of light in two-dimensional systems is limited to one single polarization. Here, we present dual-polarization two-dimensional valley photonic crystals by simultaneously opening two frequency accidental degenerate Dirac cones. Two band gaps with different polarizations are characterized by opposite-valley Chern numbers, which are confirmed by the opposite-phase vortex distributions of bulk modes and opposite Berry curvatures. This situation results in the polarization-dependent refraction of bulk and edge modes, which locate in opposite valleys. The polarization-independent topological valley transport is also demonstrated. Our work shows the flexible control of light in topological photonic systems with a polarization degree of freedom and has applications in polarization multiplexing photonic devices.

关键词： topological photonics valley photonic crystals polarization

Second Chern crystals with inherently non-trivial topology

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National Science Review 2023年第8期10卷 148-155页

作者： Xiao-dong Chen Fu-Long Shi jian-Wei Liu Ke Shen Xin-Tao He C.T. Chan wen-Jie Chen jian-wen dong School of Physics and State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen University Department of Physics The Hong Kong University of Science and Technology

Chern insulators have been generalized to many classical wave systems and thereby lead to many potential applications such as robust waveguides, quantum computation and high-performance lasers. However, the band structure of a material can be either topologically trivial or non-trivial, depending on how the crystal structure is designed. Here, we propose a second Chern crystal in a four-dimensional parameter space by introducing two extra synthetic translation dimensions. Since the topology of the bulk bands in the synthetic translation space is intrinsically non-trivial, our proposed four-dimensional crystal is guaranteed to be topologically non-trivial regardless of the crystal’s detailed configuration. We derive the topologically protected modes on the lower dimensional boundaries of such a crystal via dimension ***, we observe the one-dimensional gapless dislocation modes and confirm their robustness in experiments. Our findings provide novel perspectives on topologically non-trivial crystals and may inspire designs of classical wave devices.

关键词： topological photonics synthetic dimension photonic crystals dislocation mode

Ideal nodal rings of one-dimensional photonic crystals in the visible region

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Light(Science & Applications) 2022年第6期11卷 1178-1185页

作者： Wei-Min Deng Ze-Ming Chen Meng-Yu Li Chao-Heng Guo Zhong-Tao Tian Ke-Xin Sun Xiao-dong Chen wen-Jie Chen jian-wen dong School of Physics&State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen University510275 GuangzhouChina

Three-dimensional(3D)artificial metacrystals host rich topological phases,such as Weyl points,nodal rings,and 3D photonic topological *** topological states enable a wide range of applications,including 3D robust waveguides,one-way fiber,and negative refraction of the surface ***,these carefully designed metacrystals are usually very complex,hindering their extension to nanoscale photonic ***,we theoretically proposed and experimentally realized an ideal nodal ring in the visible region using a simple 1D photonic *** TT-Berrry phase around the ring is manifested by a 2π reflection phase's winding and the resultant drumhead surface *** breaking the inversion symmetry,the nodal ring can be gapped and the n-Berry phase would diffuse into a toroidal-shaped Berry flux,resulting in photonic ridge states(the 3D extension of quantum valley Hall states).Our results provide a simple and feasible platform for exploring 3D topological physics and its potential applications in nanophotonics.

关键词： topological nodal visible

Constructed wetlands for wastewater treatment in cold climate--A review

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Journal of Environmental Sciences 2017年第7期29卷 293-311页

作者： Mo Wang dong Qing Zhang jian wen dong Soon Keat Tan College of Landscape Architecture Fujian Agriculture and Forestry UniversityFuzhou 350002China Nanyang Environment&Water Research Institute 1 CleanTech Loop#06-10637141Singapore School of Civil and Environmental Engineering Nanyang Technological University639798Singapore

Constructed wetlands（CWs） have been successfully used for treating various wastewaters for decades and have been identified as a sustainable wastewater management option ***,the application of CW for wastewater treatment in frigid climate presents special *** treatment of wastewater relies largely on biological processes,and reliable treatment is often a function of climate *** date,the rate of adoption of wetland technology for wastewater treatment in cold regions has been slow and there are relatively few published reports on CW applications in cold *** paper therefore highlights the practice and applications of treatment wetlands in cold climate.A comprehensive review of the effectiveness of contaminant removal in different wetland systems including：（1） free water surface（FWS） CWs;（2） subsurface flow（SSF） CWs;and（3） hybrid wetland systems,is *** emphasis of this review is also placed on the influence of cold weather conditions on the removal efficacies of different *** strategies of wetland design and operation for performance intensification,such as the presence of plant,operational mode,effluent recirculation,artificial aeration and in-series design,which are crucial to achieve the sustainable treatment performance in cold climate,are also *** study is conducive to further research for the understanding of CW design and treatment performance in cold climate.

关键词： Constructed wetlands Wastewater treatment Nutrient Cold climate

Recent advances in vacancy engineering for reliable lithiumsulfur batteries

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Rare Metals 2024年第2期43卷 455-477页

作者： wen-dong Liu Xiao Tang Jun-An Feng Chao-Yue Zhang Hao Liu Chuan Shi Xiao-Xian Zhao jian-Jun Song College of Physics School of Chemistry and Chemical EngineeringQingdao UniversityQingdao266071China Faculty of Science Centre for Clean Energy TechnologySchool of Mathematical and Physical SciencesUniversity of Technology SydneySydneyNSW2007Australia Department of Chemistry College of ScienceHebei Agricultural UniversityBaoding071001China

The high-energy-density and low-cost features endow lithium-sulfur batteries with broad application ***,many drawbacks,especially the detrimental shuttle effect,have hindered the further development of *** response,a lot of new structures have been applied to suppress the shuttle effect and promote the development of ***,vacancy engineering has gained the attention of researchers due to its unique electronic *** review aims to analyze the application of vacancy engineering in ***,the electrochemistry of LSBs has been systematically discussed and the existing challenges as well as improvement tactics of LSBs have also been ***,the preparation methods and characterization technologies of various vacancies are summarized,including oxygen vacancies,sulfur vacancies,selenium vacancies,other anion vacancies,cation vacancies,*** latest applications of vacancy engineering in LSBs are also summarized in this ***,some prospects and insights for further investigation and practical application of vacancy engineering in LSBs are put forward.

关键词： Lithium-sulfur batteries(LSBs) Defects Vacancy engineering Electronic structure Shuttle effect

Carbon nanofibers embedded with Fe-Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

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Rare Metals 2024年第6期43卷 2769-2783页

作者： wen-Jun Cai jian-Guo jiang Zi-dong Zhang Zi-Xuan Liu Lu-JieZhang Zhen-Kun Long Ke Bi Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China Energy Institute Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China State Key Laboratory of Information Photonics and Optical Communications School of ScienceBeijing University of Posts and TelecommunicationsBeijing 100876China

As a lot of electromagnetic pollution and interference issues have emerged,to overcome electromagnetic interference,prevent electromagnetic hazards,and develop new high-performance electromagnetic wave(EMW)absorbers have become a significant task in the field of materials *** this paper,a three-dimensional(3D)carbon nanofibers network with core-shell structure,embedded with varied molar ratios of iron and cobalt(4:0,3:1,2:2,1:3,0:4),was effectively synthesized(Fe/Co@C-CNFs)via *** phase,microstructure,magnetic and EMW absorption properties were *** is discovered that Fe/Co@C-CNFs doped with iron:cobalt=1:1 have excellent EMW absorption *** the matching thickness is 1.08 mm,the minimum reflection loss(RL)value is-18.66 dB,while the maximum effective absorption bandwidth(EAB)reaches 4.2 GHz(13.9-18 GHz)at a thickness of 1.22 *** is owing to the absorbers'superior impedance matching and multiple reflections as well as the conductivity,dielectric,and magnetic losses of carbon nanofibers embedded with Fe-Co alloy *** addition,the radar cross section(RCS)of the absorbers has been calculated by CST Studio Suite,showing that the absorbing coating can effectively reduce the RCS at various angles,especially for Fe/Co@C-CNFs doped with iron:cobalt=1:*** findings not only provide new insights for the preparation of light-weight and high-performance electromagnetic wave absorbers,but also contribute to energy storage and conversion.

关键词： Electromagnetic wave(EMW)absorbers Fe/Co@C-CNFs Core-shell structure EMW absorbing mechanism Radar cross section(RCS)

NAD(P)H inspired CO_(2) reduction and beyond

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Science China Chemistry 2024年第4期67卷 1044-1046页

作者： wenjin dong jian Liu Qingdao Institute of Bioenergy and Bioprocess Technology Chinese Academy of SciencesShandong Energy InstituteQingdao 266101China

The catalytic reduction of carbon dioxide to fuels and valueadded chemicals under mild conditions is recognized as a promising strategy to alleviate the energy *** the Calvin cycle of natural photosynthesis,CO_(2)reduction is achieved using cofactor nicotinamide adenine dinucleotide phosphate(NADPH)as a practical catalyst,shedding light on the biomimetic metal-free reduction of CO_(2).

关键词： dioxide dinucleotide catalyst

A Review on Particle Reinforced Mg Matrix Composites Fabricated by Powder Metallurgy

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 391-400页

作者： Zhiyuan Liu Li Jin jian Zeng Fulin Wang Fenghua Wang Shuai dong Jie dong National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This paper provides a comprehensive review of research progress in particle-reinforced Mg matrix composites prepared via powder *** article discusses different strategies,such as micro-sized,nano-sized particles,and multi-particle hybridization,which has been employed to enhance the performance of the *** addition,a range of preparation techniques that optimize the dispersion of the reinforcing particles are *** paper also highlights how the different configurations between the reinforcements and matrix alloy impact the composites’***,the article outlines the prospects of particles reinforced Mg matrix composites fabricated via powder metallurgy and recommends modification methods that could be explored to further develop these materials for various applications.

关键词： Magnesium matrix composites Reinforcing particle Powder metallurgy Mechanical properties Configuration

Current status of liver transplantation for human immunodeficiency virus-infected patients in China's Mainland

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World Journal of Gastroenterology 2024年第14期30卷 1958-1962页

作者： jian-Xin Tang dong Zhao Department of Liver Surgery and Organ Transplantation Center Shenzhen Third People’s HospitalThe Second Affiliated Hospital of Southern University of Science and TechnologyNational Clinical Research Center for Infectious DiseaseShenzhen 518000Guangdong ProvinceChina

According to the report from the Chinese Center for Disease Control and Prevention,the prevalence of human immunodeficiency virus(HIV)infection exceeded 1.2 million individuals by the year 2022,with an annual increase of about 80000 *** overall prevalence of hepatitis B surface antigen among individuals co-infected with HIV reached 13.7%,almost twice the rate of the general population in *** addition to the well-documented susceptibility to opportunistic infections and new malignancies,HIV infected patients frequently experience liver-related organ damage,with the liver and kidneys being the most commonly *** often leads to the development of end-stage liver and kidney ***,organ transplantation has emerged as an important part of active treatment for HIV infected ***,the curative effect is not *** infection has been considered a contraindication for organ *** the emergence of highly active anti-retroviral therapy in 1996,the once intractable replication of retrovirus was effectively *** prolonged survival,the failure of important organs has become the main cause of death among HIV ***,transplant centers worldwide have resu-med exploration of organ transplantation for HIV-infected individuals and reached a positive *** study provides an overview of the current landscape of HIV-positive patients receiving liver transplantation(LT)in main-land *** date,our transplant center has conducted LT for eight end-stage liver disease patients co-infected with HIV,and all but one,who died two months postoperatively due to sepsis and progressive multi-organ failure,have *** analysis with hepatitis B virus-infected patients during the same period revealed no statistically significant differences in acute rejection reactions,cytomegalovirus infection,bacteremia,pulmonary infections,acute kidney injury,new-onset cancers,or vascular and biliary co

关键词： Liver transplantation Human immunodeficiency virus Infection Hepatitis B virus End-stage liver disease China'Mainland