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Character Diagnosis for Surface-Wave Plasmas Excited by Surface Plasmon Polaritons

Plasma Science and technology 2012年第8期14卷 754-758页

作者：陈兆权夏广庆刘明海胡业林郑晓亮李平周启燕胡希伟 College of Electrical&Information Engineering Anhui University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology State Key Laboratory of Structure Analysis for Industrial Equipment Dalian University of Technology

The plasma parameters of planar-type surface-wave plasmas （SWPs） are diagnosed based on the resonant excitation of surface plasmon polaritons （SPPs）. The plasma parameter distributions are obtained by changing the discharge conditions of gas pressure and incident power. The measured experimental results show that the plasma near the heating layer is excited by surface waves of SPPs while the plasma located downstream originates from diffusion Moreover, the influence of high-frequency oscillations plays a significant role in producing the proposed SWPs with bi-Maxwellian electron energy distributions.

关键词： surface-wave plasmas plasma diagnosing surface plasmon polaritons

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LIF diagnostics of hydroxyl radical in a methanol containing atmospheric-pressure plasma jet

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Chinese Physics B 2016年第10期25卷 238-243页

作者：钱沐杨刘三秋裴学凯卢新培张家良王德真 Department of Physics Nanchang University China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology School of Physics and Optoelectronic Technology Dalian University of Technology

In this paper, a pulsed-dc CH;OH/Ar plasma jet generated at atmospheric pressure is studied by laser-induced fluorescence（LIF） and optical emission spectroscopy（OES）. A gas–liquid bubbler system is proposed to introduce the methanol vapor into the argon gas, and the CH3OH/Ar volume ratio is kept constant at about 0.1%. Discharge occurs in a 6-mm needle-to-ring gap in an atmospheric-pressure CH;OH/Ar mixture. The space-resolved distributions of OH LIF inside and outside the nozzle exhibit distinctly different behaviors. And, different production mechanisms of OH radicals in the needle-to-ring discharge gap and afterglow of plasma jet are discussed. Besides, the optical emission lines of carbonaceous species, such as CH, CN, and C;radicals, are identified in the CH;OH/Ar plasma jet. Finally, the influences of operating parameters（applied voltage magnitude, pulse frequency, pulsewidth） on the OH radical density are also presented and analyzed.

关键词： atmospheric-pressure plasma jet hydrocarbon OH radicals laser-induced fluorescence

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Characterizing the thermo-optic coefficient of gallium phosphide-on-insulator platform using high-quality ring resonators

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Applied Physics Letters 2025年第16期126卷

作者： Cheng, Weiren Ding, Ning Zhang, Xucheng Liu, Zhenyu Tang, Xingyu Lin, Wenfu Wang, Yifan Pan, Ziyu Bu, Naiqin You, Mingjian Ji, Xingchen Li, Yi Zhao, Qiancheng School of Microelectronics MOE Engineering Research Center of Integrated Circuits for Next Generation Communications Southern University of Science and Technology Guangdong Shenzhen518000 China John Hopcroft Center for Computer Science School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University Shanghai200240 China State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shanghai200240 China

Characterizing a material's thermo-optic coefficient lays the foundation for optimizing thermal tuning of photonic integrated devices, a key feature for applications in optical communication, sensing, and signal processing. Unlike traditional bulk measurements, determining the thermo-optic coefficient (TOC) in microscale photonic devices offers significant advantages in data processing and provides more direct relevance to real-world device performance. In this work, we characterize the TOC of gallium phosphide (GaP) films using an air-cladded ring resonator, built on a GaP-on-insulator (GaP-OI) architecture. The resonator is fabricated via an optimized "etch-n-transfer" process, which incorporates silicon dioxide hard masks to enhance the precision of pattern transfer and improve the waveguide surface cleanliness, reducing defects and ensuring better device performance. The fabricated resonator exhibits a loaded quality factor of (2.18 ± 0.1)×104 at 1550 nm by using contact lithography, with a waveguide propagation loss of 23.8 ± 0.3 dB/cm. At 780 nm, the propagation loss decreases to 16.7 dB/cm. The resonator also shows a temperature-dependent wavelength shift of 65.8 pm/K, allowing us to extract a TOC of 1.19 × 10−4/K for GaP. This high temperature sensitivity empowers the GaP-OI platform particularly well-suited for rapid thermal turning, which is beneficial for a range of applications including optical sensing, optical signal processing, and highly efficient nonlinear conversion. © 2025 Author(s).

关键词： Surface cleaning

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Three-stage method for intentional controlled islanding of power systems

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Journal of Modern Power Systems and Clean Energy 2018年第4期6卷 691-700页

作者： Shaoxiang XU Shihong MIAO State Key Laboratory of Advanced Electromagnetic Engineering and Technology Hubei Electric Power Security and High Efficiency Key Laboratory School of Electrical and Electronic Engineering Huazhong University of Science and Technology

Controlled islanding of power system is an emer-gency control to stop the propagation of disturbances and to avoid blackouts. This paper presents a three-stage method for intentional controlled islanding of power systems. It enables to search out reasonable islanding cutsets, which have the minimum load-generation imbalance or the minimal power flow disruption, without low-voltage problems. In the first stage, a self-adaptive graph simplification algorithm is proposed to obtain a two-terminal graph as a suitable islanding cutset search area from the original power network graph model. In the second stage, an islanding cutset search algorithm is designed to find all of islanding cutsets, including the minimum load-generation imbalance cutset, in the two-terminal graph. In the third stage, an islanding scheme checking algorithm is developed to examine the outputs of stage two. It uses the depth first search algorithm to determine reasonable islanding cutsets without low-voltage problems. The IEEE30-bus system and the IEEE 118-bus system are utilized to demonstrate the proposed method. The simulation results show its validity and accuracy in large-scale power systems.

关键词： Intentional controlled islanding Islanding cutset Power flow tracing Minimal power imbalance Minimal power flow disruption

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Symmetry breaking of large-amplitude parametric oscillations in a few-layer graphene nanomechanical resonator

arXiv

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arXiv 2025年

作者： Yang, Chen Zhang, YuBin Lu, Heng Zhang, Ce Chen, FengNan Yan, Ying Xue, Fei Eichler, Alexander Moser, Joel School of Optoelectronic Science and Engineering Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou215006 China Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province Key Lab of Modern Optical Technologies of Education Ministry of China Soochow University Suzhou215006 China School of Physics Hefei University of Technology Hefei230601 China Laboratory for Solid State Physics ETH Zürich Zürich8093 Switzerland

Graphene nanomechanical resonators are well suited for the study of parametric oscillations. Their large frequency tunability and their pronounced nonlinearities enable an efficient modulation of their resonant frequency. Here, we present measurements of the response of a few-layer graphene nanomechanical resonator driven by a large parametric pump at frequency 2ω and a weak external drive at ω, where ω is set near the mechanical resonant frequency ω0. The pump actuates the resonator beyond the threshold for large-amplitude parametric oscillations, while the drive breaks the symmetry of the parametric phase states. By increasing and decreasing a gate voltage to detune ω0 in the presence of the pump and the drive, we observe a double hysteresis in the response. The double hysteresis reveals the existence of two possible large-amplitude vibrational states whose phase difference is nearly π radians. We deterministically prepare the resonator in either one of these states by cycling the gate voltage. We measure the stationary occupation probabilities of the two states in the presence of a white Gaussian force noise, and find that they strongly depend on the amplitude and on the phase of the external drive. Parametric oscillations with broken phase symmetry hold promise as units of binary information. Their phase states can be mapped to biased bi-modal degrees of freedom, such as Ising spins in an external magnetic field. Our work invites future studies on coupled graphene parametric resonators whose phase states may be mapped to a system of Ising spins. © 2025, CC BY.

关键词： Natural frequencies

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Functional perturbation theory under axisymmetry: Simplified formulae and their uses for tokamaks

arXiv

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arXiv 2025年

作者： Wei, Wenyin Liao, Liang Knieps, Alexander Hua, Jiankun Liang, Yunfeng Liu, Shaocheng Institute of Plasma Physics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei230031 China University of Science and Technology of China Hefei230026 China Forschungszentrum Jülich GmbH Institute of Fusion Energy and Nuclear Waste Management – Plasma Physics Jülich52425 Germany International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China College of Physics Donghua University Shanghai201620 China

In strictly axisymmetric configurations of tokamaks, field-line tracing reduces from a three-dimensional ODE (ordinary differential equation) system to a two-dimensional one, where Poincaré-Bendixson theorem applies and guarantees the nonexistence of chaos. The formulae of functional perturbation theory (FPT) mostly simplify to compact closed-form expressions to allow the computation to finish instantly, which could improve and accelerate the existing plasma control systems by detangling the plasma dynamics from the magnetic topology change. FPT can conveniently calculate how the key geometric objects of magnetic topology: • the divertor X-point(s) and the magnetic axis (which represent the X/O-cycles respectively), • the last closed flux surface (LCFS for short, which is the (un)stable manifolds of the divertor X-point for tokamaks when axisymmetry is guaranteed) • flux surfaces (i.e. invariant tori, where invariant means the field lines on such a torus would never leave the torus) change under perturbation. For example, when the divertor X-point shifts outwards, the LCFS there must expand accordingly, but not necessarily for other places of the LCFS, which could also contract, depending on the perturbation. FPT can not only facilitate adaptive control of plasma, but also enable utilizing as much as possible space in the vacuum vessel by weakening the plasma-wall interaction (PWI) via tuning the eigenvalues of Dpm of the divertor X-point(s), such that the field line connection lengths in the scrape-off layer (SOL) are long enough to achieve detachment. Increasing flux expansion fx is another option for detachment and can also be facilitated by FPT. Apart from the edge, FPT can also benefit the understanding of the plasma core. Since the magnetic axis O-point would also shift under perturbation and the shift is known by FPT, the O-point can be controlled without full knowledge of the plasma response, which shall not significantly change the tendency. On the other ha

关键词： Tokamak devices

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Mitigation measures of the electric field in the medium-voltage power module:Effect of voltage types and recommendations for designers

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High Voltage 2021年第5期6卷 836-849页

作者： Zhizhao Huang Cai Chen Yong Kang Stig Munk-Nielsen Christian Uhrenfeldt State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhanChina Department of Energy Technology Aalborg UniversityAalborgDenmark

In the medium‐voltage silicon carbide device power module,the higher voltage level will induce higher electric field stress in critical internal points such as the edge of the conductor on the direct bonded copper(DBC)*** can lead to partial discharge and subsequently accelerated ageing of the insulating medium in the ***,it is important to reduce the high electric field ***,the related technical methods of electric field control are reviewed and compared by combining the ease of implementation in real power module and the field control *** addition,systematic explanations of the electric field drift and influencing factors of the electric field strength under different voltage types within different module structures are ***,for half‐bridge power modules with different substrates structures,sug-gestions on how to implement non‐linear field‐dependent materials to reduce the electric field strength are given.

关键词： power field measures

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Study of the Characteristics and Suppression of EMI of Inverter with SiC and Si Devices

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Chinese Journal of Electrical engineering 2018年第3期4卷 37-46页

作者： Zhihao Fang Dong Jiang Yechi Zhang State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The paper systematically studies the impacts of two major factors:device switching actions and inverter switching frequency on the whole EMI *** powerful experimental results of electromagnetic interference(EMI)in voltage source inverter(VSI)with SiC and Si devices are *** far as the influence of switching actions is concerned:faster switching speed will generate higher EMI noise levels in the high frequency range,and ringing in the device switching will also make the EMI noise near the ringing frequency range *** the meantime,increasing of the switching frequency of the inverter will result in a higher EMI noise peak for the whole EMI *** order to suppress the EMI noise of the converter to meet standards,Random PWM(RPWM)and EMI filters are *** RPWM,the EMI current can drop a few more dB than that with SVPWM,which makes the filter work ***,as extra attenuation can be provided,it provides the benefit of reducing the weight and volume of the inductor of the ***,the combination of an advanced modulation strategy and EMI filter is proposed for suppressing of EMI noise in an inverter.

关键词： Motor drive EMI SiC ringing EMI filter PWM

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Improved Hybrid Method to Calculate Inductances of Permanent Magnet Synchronous Machines with Skewed Stators Based on Winding Function Theory

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Chinese Journal of Electrical engineering 2016年第1期2卷 52-61页

作者： Yuting Gao Ronghai Qu Dawei Li State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China

An improved hybrid method combining two dimensional(2D)finite element analysis(FEA)and the analytical method is put forward to calculate the stator winding inductance and synchronous inductance influenced by stator skewing *** on winding function theory(WFT),the improved method proposes two factors to describe variable inductances along the stator skewing *** simulations are then performed on three interior permanent magnet synchronous machines(IPMSMs),one normal and two skewed machines(half slot and one slot pitch skewing respectively).Extensive experiments are conducted on relevant prototypes with good ***,analysis and comparisons are made as to the influence of different skewing angles on the inductances and torque-speed *** is found that Ld increases and Lq decreases by skewing,leading to the reduction of the rotor saliency and maximal torque capability,but increase of the flux weakening capability.

关键词： Finite element analysis(FEA) inductances permanent magnet synchronous machine(PMSM) skewing winding function theory(WFT).

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Low-carbon Operation of Combined Heat and Power Integrated Plants Based on Solar-assisted Carbon Capture

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Journal of Modern Power Systems and Clean Energy 2022年第5期10卷 1138-1151页

作者： Xusheng Guo Suhua Lou Yaowu Wu Yongcan Wang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhan 430074China State Grid Sichuan Electric Power Research Institute Chengdu 610041China

Accelerating the development of renewable energy and reducing CO_(2)emissions have become a general consensus and concerted action of all countries in the world. The electric power industry, especially thermal power industry, is the main source for fossil energy consumption and CO_(2)emissions. Since solvent-based post-combustion carbon capture technology would bring massive extra energy consumption, the application of solar-assisted carbon capture technology has attracted extensive attention. Due to the important role of coal-fired combined heat and power plants for serving residential and industrial heating districts, in this paper, the low-carbon operation benefits of combined heat and power integrated plants based on solar-assisted carbon capture(CHPIP-SACC) are fully evaluated in heat and power integrated energy system with a high proportion of wind power. Based on the selected integration scheme, a linear operation model of CHPIP-SACC is developed considering energy flow characteristics and thermal coupling interaction of its internal modules. From the perspective of system-level operation optimization, the day-ahead economic dispatch problem based on a mix-integer linear programming model is presented to evaluate the low-carbon benefits of CHPIP-SACC during annual operation simulation. The numerical simulations on a modified IEEE 39-bus system demonstrate the effectiveness of CHPIP-SACC for reducing CO_(2)emissions as well as increasing the downward flexibility. The impact of different solar field areas and unit prices of coal on the low-carbon operation benefits of CHPIP-SACC is studied in the section of sensitivity analysis.

关键词： Solar-assisted carbon capture CO_(2)emission reduction combined heat and power integrated plant heat and power integrated energy system wind power

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