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Bio-Inspired Microwave Modulator for High-Temperature Electromagnetic Protection,Infrared Stealth and Operating Temperature Monitoring 被引量:2
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作者 Xuan Yang Yuping Duan +4 位作者 Shuqing Li Huifang Pang Lingxi Huang Yuanyuan Fu Tongmin Wang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第2期124-135,共12页
High-temperature electromagnetic(EM) protection materials integrated of multiple EM protection mechanisms and functions are regarded as desirable candidates for solving EM interference over a wide temperature range.In... High-temperature electromagnetic(EM) protection materials integrated of multiple EM protection mechanisms and functions are regarded as desirable candidates for solving EM interference over a wide temperature range.In this work,a novel microwave modulator is fabricated by introducing carbonyl iron particles(CIP)/resin into channels of carbonized wood(C-wood).Innovatively,the spaced arrangement of two microwave absorbents not only achieves a synergistic enhancement of magnetic and dielectric losses,but also breaks the translational invariance of EM characteristics in the horizontal direction to obtain multiple phase discontinuities in the frequency range of 8.2-18.0 GHz achieving modulation of reflected wave radiation direction.Accordingly,CIP/C-wood microwave modulator demonstrates the maximum effective bandwidth of 5.2 GHz and the maximum EM protection efficiency over 97% with a thickness of only 1.5 mm in the temperature range 298-673 K.Besides,CIP/C-wood microwave modulator shows stable and low thermal conductivities,as well as monotonic electrical conductivity-temperature characteristics,therefore it can also achieve thermal infrared stealth and working temperature monitoring in wide temperature ranges.This work provides an inspiration for the design of high-temperature EM protection materials with multiple EM protection mechanisms and functions. 展开更多
关键词 microwave modulator Electromagnetic protection High temperatures Temperature monitoring Carbonized wood
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Magnetic sensitivity technology based on microwave modulation of solid state spin system NV center 被引量:1
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作者 GAO Jian ZHAO Juan +4 位作者 MA Zong-min FU Yue-ping ZHANG Shao-wen LIN Zhao-dong SONG Jian 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2018年第2期188-193,共6页
In view of the low resolution and accuracy of traditional magnetometer,a method of microwave frequency modulation technology based on nitrogen-vacancy(NV)center in diamond for magnetic detection was proposed.The magne... In view of the low resolution and accuracy of traditional magnetometer,a method of microwave frequency modulation technology based on nitrogen-vacancy(NV)center in diamond for magnetic detection was proposed.The magnetometer studied can reduce the frequency noise of system and improve the magnetic sensitivity by microwave frequency modulation.Firstly,ESR spectra by sweeping the microwave frequency was obtained.Further,the microwave frequency modulated was gained through the mixed high-frequency sinusoidal modulation signal generated by signal generator.In addition,the frequency through the lock-in amplifier was locked,and the signal which was proportional to the first derivative of the spectrum was obtained.The experimental results show that the sensitivity of magnetic field detection can reach 17.628 nT/Hz based on microwave frequency modulation technology.The method realizes high resolution and sensitivity for magnetic field detection. 展开更多
关键词 solid state spin system nitrogen vacancy(NV)center microwave frequency modulation magnetic sensitivity technology lock-in amplifier
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On peak current in atmospheric pulsemodulated microwave discharges by the PIC-MCC model 被引量:2
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作者 张远涛 刘雨 刘冰 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第8期80-89,共10页
Pulse modulation provides a new way to tailor the electron density, electron energy and gas temperature in atmospheric radio-frequency(rf) discharges. In this paper, by increasing the rf frequency to several hundred... Pulse modulation provides a new way to tailor the electron density, electron energy and gas temperature in atmospheric radio-frequency(rf) discharges. In this paper, by increasing the rf frequency to several hundreds of MHz, or even much higher to the range of GHz, a very strong peak current in the first period(PCFP) with much larger electron energy can be formed during the power-on phase, which is not observed in the common pulse modulation discharges at a rf frequency of 13.56 MHz. The PIC-MCC model is explored to unveil the generation mechanism of PCFP, and based on the simulation data a larger voltage increasing rate over a quarter of a period and the distribution of electron density just before the power-on phase are believed to play key roles; the PCFP is usually produced in the microplasma regime driven by the pulsed power supply. The effects of duty cycle and pulse modulation frequency on the evolution of PCFP are also discussed from the computational data. Therefore, the duty cycle and pulse modulation frequency can be used to optimize the generation of PCFP and high-energy electrons. 展开更多
关键词 microwave cycle hundreds figure quarter unveil tailor modulated initially anode
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Pulse modulated microwave and infrared thermography for superficial hyperthermia
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作者 马国军 江国泰 陈志宏 《Journal of Central South University》 SCIE EI CAS 2012年第7期1927-1931,共5页
A 3D temperature field distribution of biological tissue for superficial hyperthermia using a pulse modulated microwave (PMMW) was presented. A 3D sliced homogeneous phantom was radiated by the PMMW and an infrared ... A 3D temperature field distribution of biological tissue for superficial hyperthermia using a pulse modulated microwave (PMMW) was presented. A 3D sliced homogeneous phantom was radiated by the PMMW and an infrared thermal imager was applied to image temperature distribution throughout the phantom. The period of the PMMW is 3 s and the output power is 35 W. The temperature rises by at least 3 ℃ in the phantom when the duty cycle varies from 1/3, 1/2, 2/3 to 1 (denoted by scenarios 1-4). Both the accumulative temperature-volume histogram and the relative depth-area ratio histogram show that the maximum temperature rise (MTR) is 6.6 and 8 ℃ in scenarios 2 and 3, and they are superior to scenarios 1 and 4. Furthermore, the PMMW can control temperature field distribution of biological tissue. It provides both preliminary basis for thermal volume control and new technology for temperature control and monitor in superficial hyperthermia. 展开更多
关键词 3D temperature field distribution pulse modulated microwave (PMMW) infrared thermography superficialhyperthermia
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Microwave Reflectometry on HL-2A Tokamak
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作者 LIU Zetian XIAO Weiwen DING Xuantong CAO Jianyong SHI Zhongbing LI Yingliang LU Jie LUO Cuiwen 《Southwestern Institute of Physics Annual Report》 2005年第1期32-34,共3页
One of the most important electron density diagnostics, microwave reflectometry, has been developed on many large and medium nuclear fusion devices in recent years . Not only the electron density profiles with high te... One of the most important electron density diagnostics, microwave reflectometry, has been developed on many large and medium nuclear fusion devices in recent years . Not only the electron density profiles with high temporal and spatial resolutions, but also the profiles of plasma rotation and turbulence can be obtained with this diagnostic system. 展开更多
关键词 microwave scanning frequency RF modulation reflection and receiver
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Microwave photonic notch filter with complex coefficient based on four wave mixing
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作者 许东 曹晔 +1 位作者 童峥嵘 杨菁芃 《Optoelectronics Letters》 EI 2016年第6期417-420,共4页
A microwave photonic notch filter with a complex coefficient is proposed and demonstrated based on four wave mixing(FWM). FWM effect of two single-frequency laser beams occurs in a highly nonlinear fiber(HNLF), and mu... A microwave photonic notch filter with a complex coefficient is proposed and demonstrated based on four wave mixing(FWM). FWM effect of two single-frequency laser beams occurs in a highly nonlinear fiber(HNLF), and multi-wavelength optical signals are generated and used to generate the multi-tap of microwave photonic filter(MPF). The complex coefficient is generated by using a Fourier-domain optical processor(FD-OP) to control the amplitude and phase of the optical carrier and phase modulation sidebands. The results show that this filter can be changed from bandpass filter to notch filter by controlling the FD-OP. The center frequency of the notch filter can be continuously tuned from 5.853 GHz to 29.311 GHz with free spectral range(FSR) of 11.729 GHz. The shape of the frequency response keeps unchanged when the phase is tuned. 展开更多
关键词 notch photonic mixing tuned processor microwave unchanged continuously tunable modulator
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A continuously tunable microwave photonic notch filter with complex coefficient based on phase modulation
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作者 XU Dong 《Optoelectronics Letters》 EI 2017年第1期13-15,共3页
A continuously tunable microwave photonic notch filter with complex coefficient based on phase modulation is proposed and demonstrated. The complex coefficient is generated using a Fourier-domain optical processor(FD-... A continuously tunable microwave photonic notch filter with complex coefficient based on phase modulation is proposed and demonstrated. The complex coefficient is generated using a Fourier-domain optical processor(FD-OP) to control the amplitude and phase of the optical carrier and radio-frequency(RF) phase modulation sidebands. By controlling the FD-OP,the frequency response of the filter can be tuned in the full free spectral range(FSR) without changing the shape and the FSR of the frequency response. The results show that the center frequency of the notch filter can be continuously tuned from 17.582 GHz to 29.311 GHz with FSR of 11.729 GHz. The shape of the frequency response keeps unchanged when the phase is tuned. 展开更多
关键词 notch photonic tunable continuously microwave tuned unchanged processor modulator coupler
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Investigation of a Novel Atmospheric Pressure Microwave Cold Plasma Torch and Its Characteristics
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作者 LI Yarui BAI Yiwen +4 位作者 YU Dengjie WANG Rongyao MU Ying JIN Wei YU Bingwen 《Chemical Research in Chinese Universities》 SCIE CAS 2024年第6期1282-1289,共8页
This study proposes a coaxial structure atmospheric pressure microwave cold plasma device that utilizes argon as the main working gas.It achieves stable formation of atmospheric pressure cold plasma jet at low power (... This study proposes a coaxial structure atmospheric pressure microwave cold plasma device that utilizes argon as the main working gas.It achieves stable formation of atmospheric pressure cold plasma jet at low power (<50 W) with a jet length ranging from 1 mm to 32 mm.The paper analyzes the composition of the cold plasma using spectroscopy and investigates its composition changes at different positions along the jet.It also studies the appearance and reaction composition of the plasma filament under different shielding gases.Furthermore,it explores the effects of continuous and modulated microwave power on the length,appearance,and composition of the plasma filament.Finally,it examines the bactericidal effect of the plasma filament on Escherichia coli under various gas conditions,providing a foundation for further application research. 展开更多
关键词 microwave cold plasma Spectral analysis Modulated microwave source Sterilization
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Output characteristics of Nd:Gd VO_4 crystals laser with dual c-axis orthogonal gains end-pumped by two fibercoupled diode lasers
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作者 林海峰 熊飞兵 黄剑平 《Optoelectronics Letters》 EI 2015年第1期30-32,共3页
The output characteristics of neodymium-doped gadolinium vanadate(Nd:GdVO4) crystals laser with dual c-axis orthogonal gains end-pumped by two fiber-coupled diode lasers are investigated. With two 1 W semiconductor di... The output characteristics of neodymium-doped gadolinium vanadate(Nd:GdVO4) crystals laser with dual c-axis orthogonal gains end-pumped by two fiber-coupled diode lasers are investigated. With two 1 W semiconductor diode lasers pumping, the output power of TEM00 laser is 920 m W, and the optical conversion efficiency is close to 46%. By changing the relative orientations of both Nd:Gd VO4 crystals, the polarization characteristics of laser are varied. In particular, by keeping the c-axes of two Nd:Gd VO4 crystals orthogonal to each other and adjusting two diode pump lasers to operate at the same power level, the completely unpolarized light is obtained. 展开更多
关键词 oscillator resonant optoelectronic modulator longitudinal branch adding microwave demonstration constructs
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