- by Bryn Davies, Stefan Szyniszewski, Marcelo A Dias, Leo de Waal, Anastasia Kisil, Valery P Smyshlyaev, Shane Cooper, Ilia V Kamotski, Marie Touboul, Richard V Craster, James R Capers, Simon A R Horsley, Robert W Hewson, Matthew Santer, Ryan Murphy, Dilaksan Thillaithevan, Simon J Berry, Gareth J Conduit, Jacob Earnshaw, Nicholas Syrotiuk, Oliver Duncan, Łukasz Kaczmarczyk, Fabrizio Scarpa, John B Pendry, Marc Martí-Sabaté, Sébastien Guenneau, Daniel Torrent, Elena Cherkaev, Niklas Wellander, Andrea Alù, Katie H Madine, Daniel J Colquitt, Ping Sheng, Luke G Bennetts, Anastasiia O Krushynska, Zhaohang Zhang, Mohammad J Mirzaali and Amir ZadpoorThis Roadmap surveys the diversity of different approaches for characterising, modelling and designing metamaterials. It contains articles covering the wide range of physical settings in which metamaterials have been realised, from acoustics and electromagnetics to water waves and mechanical systems. In doing so, we highlight synergies between the many different physical domains and identify commonality between the main challenges. The articles also survey a variety of different strategies and philosophies, from analytic methods such as classical homogenisation to numerical optimisation […]
- by Yang Yang, Lin Wang, Jie Yuan, Dongdi Yin, Shunhong Zhao, Yongsheng Long and Dejiang ChenTo enhance the ablation resistance of cathodes in high-power arc heaters, this study pioneered an innovative methodology through synergistic integration of ultra-high-speed laser cladding with micro-multi-electrodes technology. Capitalizing on the matched emissivity characteristics between LaB6 and copper matrix, in situ fabrication of arc dielectric coating was achieved on the copper matrix. LaB6 has strong electron emission and tolerance to cation bombardment. It can attract and disperse the arc, forming separated arc spots that reduce electrode erosion. Analysis revealed the influence […]
- by Abinash Baruah, Himangshu Jyoti Gogoi and Arun Tej MallajosyulaPerovskite light emitting diodes (PeLEDs) based on metal halides are highly efficient and show high color purity. Here, we report a green PeLED based on methylammonium lead tribromide (MAPbBr3) with a high brightness of 13 000 cdm−2 at 6 V with a narrow full-width half-maximum of 20 nm. Impedance spectroscopy revealed that these devices exhibit giant polarization facilitating ion-migration and, subsequently, performance degradation. Energy dispersive x-ray spectroscopy showed that the ions are the migrating species in this material. Using an equivalent […]
- by Surojit B Bera, Pratik Parsoya, Gautam S Patadiya, Renuka Pithiya, Priya Prajapati and P V KanjariyaThis paper discusses the improvement in functional properties of bismuth ferrite (BiFeO3) powder through appropriate co-doping with Samarium (Sm3+) and Manganese (Mn3+). The compounds with x = 0.04, 0.08, 0.12, and 0.16 were synthesized through the solid-state reaction method. Structural crystallography was confirmed by x-ray diffraction techniques involving Williamson–Hall analysis and Rietveld refinement. Scanning electron microscopy showed marked changes in morphology due to the process of co-doping. The dielectric measurements showed excellent compatibility in a wide range of frequency, and […]
- by Ravinder Sheoran, Kolla Lakshmi Ganapathi and Rishi Pal ChauhanThe electrospinning technique enables precise control over the synthesis of nanofibers, including their thickness, size, and uniformity. This study investigates the electrospun synthesis of aligned WO3 nanofibers, overcoming the challenge of fabricating WO3 fibres without the need for calcination at high temperature, which has been a limitation in prior research. We explore how and why the distribution of electric fields affects the WO3 nanofibers’ orientation and functional properties. By adjusting the electric field on the collector plate, we successfully aligned […]
- by Xiaojian Yan, Yao Tan, Fang Guan, Tianxun Gong, Guilin Wang, Haonan Li, Wen Huang and Xiaosheng ZhangOligomers are recognized Fano resonance structures with high near-field enhancement. However, the fabrication of such structure with nanometer geometry is still challenging. This paper introduces Fano resonance nanopatterns based on template-assisted self-assembly hepamer clusters. The gold nanoparticles were transferred on to anodized aluminum (AAO) template through liquid–liquid interface self-assembly. Due to the scale limit of the holes on AAO template and the sulfide-gold bond formed by dodecyl mercaptan, large amount of gold nanoparticle heptamers was formed. The Fano resonance generated […]
- by Shu-Zhong Liu, Rong Liu, Le-Yi Li, Fan-Yi Meng, Shanshan Xu and Chang DingThis paper presents the design and implementation of an ultra-wideband ferrite circulator. The main transmission line of the circulator adopts the form of Y junction and quarter-wavelength impedance converter. To extend the lower-frequency operating bandwidth, the design adopts double-Y and single-stub (DYSS) matching technology. DYSS is equivalent to parallel LC resonance and plays the role of reactance compensation. In addition, the composite ferrite (CF) technology is introduced innovatively which broadens the high-frequency working bandwidth effectively. CF effectively improves the magnetic […]
- by Zepeng Lv, Bingjie Wang, Chenyu Wu, Yuntong Ma and Kai WuUnder load switching or emergency load conditions, a surge in load current happens in the power system and generates temperature fluctuation in the insulation of the power equipment. The effect of temperature fluctuation on the space charge accumulation in the insulation is still unknown. This paper presents the space charge behavior in LDPE, cross-linked polyethylene (XLPE), and polypropylene (PP) under constant DC voltage with temperature fluctuation. It shows that the space charge redistributes when the temperature fluctuates, while the applied […]
- by Yi Wu, Yushi Zhang, Fengfeng Jiang, Tianxiao Liu, Hao Sun, Yifei Wu, Chunping Niu, Mingzhe Rong, Zeyuan Luo and Ziqi LiuVacuum switches are widely utilized in the medium-voltage switchgear field due to their rapid dielectric recovery characteristics and environmental friendliness. This study addresses the unclear mechanism by which anode spots affect cathode splashing erosion in vacuum arcs. Under fixed electrode distance conditions, we experimentally investigated the influence of anode spot jets on cathode splashing erosion and the relationship between cathode splashing erosion and post-arc anode temperature across various arc conditions. Two optical diagnostic methods were employed. The first method involved […]
- by Longfei Li, 龙飞 李, Hongyin Jia, 洪印 贾, Anlin Jiang, 安林 蒋, Long Wu, 龙 吴, Pengcheng Cui, 鹏程 崔, Xiaojun Wu and 晓军 吴The nanosecond pulsed surface dielectric barrier discharge for gasdynamic control in high-temperature non-equilibrium flows is modeled using the multi-species Navier–Stokes equations coupled with self-consistent drift-diffusion equations, encompassing 16 species and 36 reactions. A ‘plasma-to-fluid’ loose coupling strategy is employed, with corresponding spatial and temporal discretization applied. The simulation focuses on a proposed annular dielectric barrier discharge actuator configuration integrated into the outer surface of a simplified semi-sphere experimental model. A nanosecond voltage pulse with a peak voltage of 14 kV […]
- by Yi Feng, Yao Li, Si-Si Li, Wei Wang, Shao-Ming Qie and De-Zheng YangIn this paper, a short-gated ICCD and a streak camera were employed to investigate the dynamic evolution and the fast breakdown mechanism of dielectric barrier discharge in helium. Both the discharge evolution in nanoseconds and the fast dynamic breakdown process in tens of picoseconds were recorded, and the generation and quenching mechanisms of active species were analyzed using time-resolved spectroscopy. The results show that the discharge propagates backward from the cathode to the anode immediately after breakdown is achieved, and […]
- by Manoj Dhivakar J, Ramanujam Sarathi and Stefan KornhuberThe present work examines the surface degradation and charge transport mechanism of silicone rubber material with nano-size alumina trihydrate (ATH) and low-melting glass powder (LMGP) fillers, aged in an acid rain solution. The immersion in acid rain forms acid/salt contamination layers on the silicone rubber surfaces. Scanning electron microscope images indicate that the acidic degradation could be minimized by LMGP addition with base silicone rubber. ATH/LMGP filler addition with silicone rubber significantly enhances the contact angle, thermal conductivity and reduces […]
- by Jianfei Wang, Zhiqiang Li, Liang Ma and Yipeng ZhaoJanus two-dimensional materials have attracted extensive research attention owing to their intrinsic electric dipole moments and excellent properties. Here, a systematic study on the electronic properties of In2Se2S/WSiGeX4 (X = N, P, As) van der Waals heterostructures (vdWHs) is presented. The results showed that the different interfacial stacking configurations can modulate the net dipole moment strength and band alignment of In2Se2S/WSiGeX4 vdWHs. The In2Se2S/WSiGeP4 vdWHs exhibit type-I band alignment with direct bandgap characteristics when adopting Si(Ge)/Se interfacial contacts, whereas type-II […]
- by Subhranshu Sekhar Sahu, Soumyadip Chatterjee, Anshul Jain, Suddhasatta Mahapatra and Apurba LahaThe performance of InGaN/GaN light-emitting diodes (LEDs) is strongly influenced by non-radiative defects. Despite its significance, the phenomenon of defect saturation in LEDs has received limited attention in the literature. In this study, we investigate the effect of carrier-induced defect saturation through capacitance–voltage (C–V) measurements of InGaN/GaN LEDs. Our findings reveal that the degree of defect saturation is proportional to the level of carrier injection under quasi-equilibrium conditions. The carrier-induced defect saturation mechanism in green InGaN/GaN LEDs involves interactions between […]
- by Jie Zhang, Hao Yuan, Zikai Zhou, Rui Liang, Ke Lu, Sisi Li and Dezheng YangNeedle-to-needle discharge plasma in atmospheric pressure air environments has been proven to have applications in different fields depending on its kinds of discharge modes, which in turn lead to the importance of investigating the characteristics and mode transitions of the discharge plasma. In this paper, AC high-voltage is employed to generate a needle-to-needle bare electrodes discharge plasma in the air. The modulation of the discharge mode can be achieved by adjusting key factors such as electrode gap, capacitance and voltage, […]
- by Jian Wang, Zexi Xing, Jianzhao Zhu, Hongjian Li, Zhiyun Han, Hanwen Ren and Qingmin LiCopper–aluminum electrical contact components in the operation process will be subjected to mechanical friction and current ablation of the joint role. These components often operate under extreme conditions characterized by high current, elevated temperatures, and significant stress coupling. As a result, the interface sliding electrical contact state is severely compromised, which can lead to a degradation of the service performance of the alloy material. In this paper, copper–aluminum current-carrying friction experiments were conducted in different devices to study the microstructure […]
- by Thomas J Smart, Bilen Emek Abali, Hans Boschker and Wolfgang BraunThe modeling of deposition rates in thermal laser epitaxy (TLE) is essential for the accurate prediction of the evaporation process and for improved dynamic process control. We demonstrate excellent agreement between experimental data and a model based on a finite element simulation that describes the temperature distribution of an elemental source when irradiated with continuous wave laser radiation. The simulation strongly depends on the thermophysical constants of the material, thermal conductivity, specific heat capacity, density, reflectivity and thermal emissivity, data […]
- by Zhaoxiang Wang, Guisheng Jiang, Yijun Zheng, Hongliang Ma, Yu Liu, Ziren Zhu, Yinhui Yang, Zefan Huang, Heng Wang, Lin Chen and Rongqing TanThis study establishes a two-dimensional fluid theoretical model for a two-electrode spark gap switch, linking the behavior of microscopic particles with the macroscopic discharge phase through multiscale dynamic coupling. It further investigates the temporal characteristics of the switch’s conductive process and streamer evolution from the perspective of microscopic particles. Using the finite element analysis method, the study investigates the effects of factors such as gas pressure, operating voltage, electrode spacing, and electrode curvature on the time characteristics of key discharge […]
- by Hairui Bao, Yange Peng, Zheng Zhang, Qirui Yu, Xi Fu and Wenhu LiaoAs one type of important topological quantum states, the quantum spin Hall (QSH) effect realized in two-dimensional (2D) materials still maintains sufficient attractiveness due to its promising spintronic applications. By using the first-principles calculations, we theoretically investigate the structural, electronic and topological properties of a newly 2D honeycomb-Kagome WI3 monolayer (ML). The WI3 ML possesses the excellent dynamical, thermal and mechanical stabilities, as has been confirmed by phonon spectra, molecular dynamics simulations and elastic constants calculations, respectively. It is found […]
- by Shengxia Tan, Yi-Feng Chai, Binglin Wang, Shengwei Guo, Ru Jiang, ZhongHua Zhu, Gui-Fang Huang and Wei-Qing HuangSimultaneously achieving high charge separation efficiency and structural stability in solar-driven photocatalysts remains a critical challenge. Here, we report a Z-scheme g-C3N4/ZnS heterojunction synthesized via hydrothermal deposition, which enhances redox capabilities through efficient charge carrier transfer/separation to improve photocatalytic activity and stability. The direct interfacial chemical bonds between g-C3N4 and ZnS enable unidirectional electron transfer and minimized recombination losses. The optimized heterojunction achieves 95.75% degradation of methylene blue under visible light within 2 h—6.38-fold and 4.76-fold higher than pristine g-C3N4 […]
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