- by Shi Qiao, Jie Luo, Xiang Fang, Zhuang Wu, Yanan Zeng, Yuntao Yang, Qian Xue, Jiayi Xiong, Hongbin Fei and Yanhong ZouTunable Microwave Absorbers Can Improve The performance and flexibility of the system. Inspired by the rotation of the fan, we have designed a gradient-structured rotating tunable microwave absorber (GRTMA), which consists of two gradient distribution units on top and bottom. GRTMA has the advantages of good low-frequency performance and ultra-broadband absorption and can switch between double absorption peaks and single absorption peaks by rotating the upper unit. Experimental results have shown that GRTMA can achieve 90% absorption within the 2.56–18 […]
- by Thomas V Kerber, Nathaniel J Allwine, Kristina M Lemmer and Nicholas R TaylorLuminescence at the face of ionic liquid ion sources and nearby facility surfaces is a commonly reported radiative phenomenon that requires thorough examination. In this study, we present magnified images of a single emitter porous-media ionic liquid electrospray in profile, which provides spatial information on the origin of the luminescence. To determine what role facility interactions play in luminescence at the electrospray face, we varied the distance and material of a downstream beam target on which the ion plume terminated. […]
- by H Rezaei, M Kazemi, M Saeedi, A Jahangirian and M ManiThis study aims to investigate the flow control performance of linear and serpentine dielectric barrier discharge (DBD) plasma actuators mounted on the leading edge of a NACA0012 airfoil to control flow separation and improve aerodynamic performance. Experiments were conducted in a subsonic wind tunnel at Reynolds numbers of 87 × 103, 131 × 103, and 175 × 103. Velocity profiles in the wake and static pressure distributions over airfoil were measured using hot-wire anemometry and pressure sensors, respectively. All experiments […]
- by Thomas V Kerber, Nathaniel J Allwine, Kristina M Lemmer and Nicholas R TaylorLuminescence spectroscopy was used to examine the dynamics of propellant dissociation near the emitter tip of a single-emitter porous electrospray thruster loaded with the ionic liquid EMI-BF4. Luminescence spectra from CH, C2, CN, NH, BH, Hα, and Hβ were observed and confirmed by comparison with simulated spectra. Analysis of the CH (A 2Δ, v′ = 0) spectra yielded a rotational temperature 3082 ± 30 K while the C2 (d 3Πg− a 3Πu) Swan system yielded rotational temperatures 6252 ± 92 […]
- by Huadian Zhang, Qingrui Jiang, Yiwei Han, Michael R Fiske, Jennifer E Edmunson and Shan Jiang
- by Ziyu XingThe viscoelastic responses of polymers, such as relaxation and creep, are substantially influenced by their mechanical and rheological behaviors, which are governed by the dynamics of polymer chains. Soft polymers, distinguished by their complex and nonlinear mechanical characteristics, offer a broad spectrum of potential applications across diverse sectors. To address these complexities, this paper introduces the Rouse-Bueche-Zimm bead-spring model, predicated on an internal viscosity framework, to dissect the heterogeneous and non-Markovian dynamics of polymers. This model conceptualizes polymer chains as […]
- by R Färber, O Šefl and C M FranckThe variation of the partial discharge inception voltage (PDIV) of wedge-shaped, dielectric-bounded air gaps under concurrent changes of air pressure (7.5 mbar to 950 mbar) and temperature (23 ∘C to 110 ∘C) is investigated in this paper. Two coating materials featuring distinctly different variations of their dielectric permittivity with temperature are used. The experimentally observed variation of the PDIV is shown to be in good agreement with a physical parametrization of the PDIV in terms of the general scaling parameter . The […]
- by Shengfei Shang, Xiaoning Yang, Yong Yang, Guobiao Cai, Weizong Wang, Bijiao He and Baiyi ZhangThe modified Sigmund sputtering formula offers high computational accuracy for calculating sputtering yields and the energy distribution of sputtered atoms. This formula introduces a parameter called ‘relative threshold energy’ (Ez), which, like the sputtering threshold energy (Eth), serves as a reference for the minimum energy required for sputtering. However, Ez is significantly larger than Eth, rendering the modified Sigmund model inaccurate for sputtering calculations when E < Ez. Additionally, our previous research provided an empirical expression for Ez, but it […]
- by Yang-wan Zhong, Liang Wu, Wen-hao Li, Qing-sheng Xiao and Shi-lei XiaoAn efficient and small volume surface plasmonic vortex (PV) based on multi-arm Archimedes-spiral slot with different spiral slot parameters m is proposed and investigated. By adding an auxiliary nanocavity under the primary Archimedes-spiral slot, the surface plasmonic polaritons can be efficiently transmitted inward to form surface PV inside the multi-arm Archimedes-spiral slot. The unidirectional excitation of the surface plasmonic polaritons can be achieved by numerically optimizing the geometrical parameters of the auxiliary nanocavity with the finite-difference time-domain method. The proposed […]
- by Jianming Xiong, Zheng Chen, Tao Gong, Jiawei Dong, Wenyu Hu, Zhenyu Ma, Yong Deng, Jiawei Zheng, Xin Zhang, Jian Ma, Longqing Chen, Jinfeng Li, Xiaoyi Wang, Yang Qiu, Manyu Dang, Huiwen Deng, Mingchu Tang, Huiyun Liu, Jun Zhu and Pierre RuteranaPlatinum and Gallium Arsenide reaction is a common issue for the stability of Pt-GaAs contacts, where the formation of different alloys during the fabrication and operation degrades the performance of the devices. In this work, we have carried out in situ deposition of Pt on GaAs and InAlGaAs in the focused ion beam machine and carried out annealing in the high-resolution transmission electron microscope. The local strains were then determined using the geometrical phase analysis technique and the various phases […]
- by Dimitris Kechrakos, Andrea Meo, Francesca Garesci, Mario Carpentieri, Anna Giordano, Riccardo Tomasello and Giovanni FinocchioCurrent-driven magnetic skyrmions show promise as carriers of information bits in racetrack magnetic memory applications. Specifically, the utilization of skyrmions in synthetic antiferromagnetic (SAF) systems is highly attractive due to the potential to suppress the skyrmion Hall effect, which causes a transverse displacement of driven skyrmions relative to the shift direction. In this study, we demonstrate, through analytical calculations and micromagnetic simulations, that in the case of a nanoring geometry, current-driven skyrmions achieve a stable circular motion with a constant […]
- by Yuanbo Wang, Muchun Di, Changlin Ding, Yibao Dong, Shilong Zhai, Chunrong Luo and Xiaopeng ZhaoThe valley degrees of freedom, representing quantum states of energy extremes in momentum space, are introduced into the acoustic system, and the valley topological insulator analogs of the quantum valley Hall effect can control the sound wave to observe topological valley transport against backscattering in domain walls of different valley topological phase structures. However, most of the earlier acoustic topological insulators are based on Bragg scattering and topological states only work in a single frequency band, which limits the design […]
- by Guruprasad Sahoo, Ajit Jena, L N Patro and Gangadhar BeheraThe present study demonstrates the structural, elastic, thermal, and electronic properties of copper nitride (Cu3N) doped with transition metal M (M: Fe, Co, and Ni) using pseudopotential-based density functional calculations as implemented in the Quantum ESPRESSO simulation code. The exchange-correlation is approximated by Perdew-Burke-Ernzerhof functional within the framework of generalized gradient approximation. The doped matrices, represented as Cu3NM, are verified to be stable structures, both thermodynamically and mechanically. Tailoring of elastic properties and their anisotropy due to M doping is […]
- by Liang Liu, Shuai Zhou, Kaipeng Liu, Shiwei Dai and Lixin GeGraphene sheets support surface plasmon polaritons (SPPs) in the terahertz and infrared regimes, resulting from the collective oscillation of Dirac electrons with excited photons. The SPPs in graphene under external strains exhibit anisotropic properties, varying with the magnitude and direction of mechanical deformation. In this study, we propose an mechanical sensor based on the strain-dependent absorption spectrum of infrared light. The setup consists of a monolayer strained graphene sheet suspended over a grating silver substrate. Under a normal incidence, a […]
- by Zhuoxi Lian, Dan Wang, Xiangping Zhu and Yongning HeMicrochannel plates (MCPs) are critical devices used in electron multiplication for applications such as night vision, mass spectrometry, and particle detection. Traditional MCP fabrication using lead silicate glass faces challenges in meeting the increasing demands for high gain, long lifespan, and low noise. In this study, pursuing MCP with excellent performance, atomic layer deposition (ALD) technology was employed to prepare Ru/Al2O3 composite film and Al2O3 film as the conductive layer and secondary electron emission (SEE) layer respectively in microchannels. By […]
- by Chunjia Gao, Hao Ge, Qing Yuan, Juzhen Wu, Yanming Cao, Huidong Tian, Bo Qi and Chengrong LiThe operational temperature regime of a transformer critically influences the electric field topography and the interface charge dynamics within the oil-pressboard insulation. Employing the Kerr electro-optical phenomenon, this manuscript delineates the development of a thermal-modulated electric field mapping apparatus for oil-pressboard insulation. Empirical analyses on the electric field and interface charges under variable thermal conditions revealed the following: 1) within the single-oil-spacing model, an escalation in temperature engenders an amplified electric field intensity in oil, a diminished interface charge density, […]
- by Huamao Huang, Hongshen Zeng, Junhao Zhang and Jingqiu LiangThe pursuit of advanced illumination and display technologies has driven the development of beam manipulation for GaN micro-sized light-emitting diodes (LEDs). To realize an efficient polarization emission light source, we propose metasurface-integrated resonant cavity LEDs (RCLEDs), incorporating a dual-layer embedded photonic crystal (PhC) within the GaN cavity, and placing a resonant-cavity reflector (RCR) on top of the existing distributed Bragg reflector (denoted as PhC-RCR-RCLED). Numerical simulations reveal a significant enhancement in emission efficiency along with an improved ability to manipulate […]
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