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Identification of the highly active Zn-N_(4) sites with pyrrole/pyridine-N synergistic coordination by dz^(2)+s-band center for electrocatalytic H_(2)O_(2) production
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作者 Rui Chen Wei Liu +11 位作者 Zhiyuan Sang Jingjing Jia Zhenxin Li Jiahuan Nie Qiao Jiang Zixian Mao Baitong Guo Qiuying Wang Feng Hou Lichang Yin De'an Yang Ji Liang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第11期105-113,共9页
Single metal atoms anchored on nitrogen-doped carbon materials(M-N_(4))have been identified as effective active sites for catalyzing the two-electron oxygen reduction reaction(2e-ORR).However,the relationship between ... Single metal atoms anchored on nitrogen-doped carbon materials(M-N_(4))have been identified as effective active sites for catalyzing the two-electron oxygen reduction reaction(2e-ORR).However,the relationship between the local atomic/electronic environments of the M-N_(4) sites(metal atoms coordinated with different types of N species)and their catalytic activity for 2e-ORR has rarely been elaborated clearly,which imposes significant ambiguity for the rational design of catalysts.Herein,guided by the comprehensive density-functional theory calculations and predictions,a series of Zn-N_(4) single-atom catalysts(SACs)are designed with pyrrole/pyridine-N(N_(Po)/N_(Pd))synergistic coordination and prepared by controlling the pyrolysis temperature(600,700,and 800℃),Among them,the dominated Zn-N_(4) configurations with rationally combined N_(Po)/N_(Pd)coordination show~*OOH adsorption strength close to the optimal value,much superior to those with mono N species.Thus,the as-prepared catalyst exhibits a high H_(2)O_(2) selectivity of over 90%both in neutral and alkaline environments,with a superb H_(2)O_(2) yield of up to 33.63 mol g^(-1)h^(-1)in an alkaline with flow cell.More importantly,a new descriptor,dz^(2)+s band center,has been proposed,which is especially feasible for predicting the activity for metal types with fully occupied s and d orbitals.This work thus presents clear guidance for the rational design of highly active SACs toward ORR and provides a complement to the d-band theory for more accurately predicting the catalytic activity of the materials. 展开更多
关键词 Zinc single-atom catalysts Hydrogen peroxide Local coordination environments d+s-band modulation
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Design,fabrication,and cold test of an S-band high-gradient accelerating structure for compact proton therapy facility 被引量:4
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作者 Yu Zhang Wen-Cheng Fang +4 位作者 Xiao-Xia Huang Jian-Hao Tan Cheng Wang Chao-Peng Wang Zhen-Tang Zhao 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第4期38-48,共11页
An S-band high-gradient accelerating structure is designed for a proton therapy linear accelerator(linac)to accommodate the new development of compact,singleroom facilities and ultra-high dose rate(FLASH)radiotherapy.... An S-band high-gradient accelerating structure is designed for a proton therapy linear accelerator(linac)to accommodate the new development of compact,singleroom facilities and ultra-high dose rate(FLASH)radiotherapy.To optimize the design,an efficient optimization scheme is applied to improve the simulation efficiency.An S-band accelerating structure with 2856 MHz is designed with a low beta of 0.38,which is a difficult structure to achieve for a linac accelerating proton particles from 70 to 250 MeV,as a high gradient up to 50 MV/m is required.A special design involving a dual-feed coupler eliminates the dipole field effect.This paper presents all the details pertaining to the design,fabrication,and cold test results of the S-band high-gradient accelerating structure. 展开更多
关键词 s-band High gradient Accelerating structure COMPACT Single-room facility Dual-feed coupler Cold test
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Radio frequency conditioning of an S-band accelerating structure prototype for compact proton therapy facility 被引量:3
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作者 Yu Zhang Wen-Cheng Fang +7 位作者 Xiao-Xia Huang Jian-Hao Tan Shao-Peng Zhong Cheng-Cheng Xiao Jun-Qiang Zhang Cheng Wang Yu-Qing Yang Zhen-Tang Zhao 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第6期94-107,共14页
The development of a high-gradient accelerating structure is underway to construct a compact proton linear accelerator for cancer treatment.Extensive experiments and numerous studies are being conducted to develop com... The development of a high-gradient accelerating structure is underway to construct a compact proton linear accelerator for cancer treatment.Extensive experiments and numerous studies are being conducted to develop compact linear accelerators for proton therapy.Optimization of the electromagnetic and mechanical design has been performed to simplify the manufacturing process and reduce costs.A novel high-gradient structure with a low relativistic proton velocity(β),v/c=0.38,was designed,fabricated,and tested at high power.The first full-scale prototype was also successfully tested with high radio frequency(RF)power,a repetition rate of 50 Hz,and pulse length of 3μs to reach a high-gradient of 46 MV/m using a 50 MW S-band klystron power supply obtained from the Shanghai Soft X-ray Free Electron Laser Facility.This is the first high-power test in China,which is in line with the expected experimental goal.This study presents preliminary high-power testing of S-band standing wave accelerating structures with 11 cells.This work aims to verify the feasibility of using a high-gradient RF accelerating structure in compact proton therapy facilities.The cold test of the prototype cavity was completed in advance.Details of the high-power RF test setup,the process of RF conditioning,and the high-power results are described. 展开更多
关键词 s-band Standing wave(SW) High-gradient Accelerating structure RF conditioning
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Reliability of X-band Dual-polarization Phased Array Radars Through Comparison with an S-band Dual-polarization Doppler Radar 被引量:2
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作者 ZHOU Xin-yu HU Dong-ming +2 位作者 ZHANG Yu LI Hao-wen TIAN Cong-cong 《Journal of Tropical Meteorology》 SCIE 2022年第2期218-236,共19页
Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs)and an S-band dual-polarization Doppler weat... Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs)and an S-band dual-polarization Doppler weather radar(CINRAD/SA-D),the data reliability of DP-PAWR and its ability to detect the fine structures of mesoscale weather systems were assessed.After location matching,the observations of DP-PAWR and CINRAD/SA-D were compared in terms of reflectivity(Z_(H)),radial velocity(V),differential reflectivity(Z_(DR)),and specific differential phase(K_(DP)).The results showed that:(1)DP-PAWR has better ability to detect mesoscale weather systems than CINRAD/SAD;the multi-elevation-angles scanning of the RHI mode enables DP-PAWR to obtain a wider detection range in the vertical direction.(2)DP-PAWR’s Z_(H)and V structures are acceptable,while its sensitivity is worse than that of CINRAD/SA-D.The Z H suffers from attenuation and the Z_(H)area distribution is distorted around strong rainfall regions.(3)DP-PAWR’s Z_(DR)is close to a normal distribution but slightly smaller than that of CINRAD/SA-D.The K_(DP)products of DP-PAWR have much higher sensitivity,showing a better indication of precipitation.(4)DP-PAWR is capable of revealing a detailed and complete structure of the evolution of the whole storm and the characteristics of particle phase variations during the process of triggering and enhancement of a small cell in the front of a squall line,as well as the merging of the cell with the squall line,which cannot be observed by CINRAD/SA-D.With its fast volume scan feature and dual-polarization detection capability,DP-PAWR shows great potential in further understanding the development and evolution mechanisms of meso-γ-scale and microscale weather systems. 展开更多
关键词 comparative observations mesoscale weather systems fine structure X-band dual-polarization phased array radar s-band dual-polarization Doppler radar
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DEVELOPMENT OF 50MW S-BAND KLYSTRON 被引量:1
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作者 Wang Yong Xie Jingxin Ding Yaogen Liu Pukun 《Journal of Electronics(China)》 2006年第3期471-472,共2页
This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences (IECAS). It adopted a structure of six-cavity and single output window. Under conditions of ... This letter reports the development of a 50MW S-band klystron in the Institute of Electronics, Chinese Academy of Sciences (IECAS). It adopted a structure of six-cavity and single output window. Under conditions of an RF (Radio Frequency) pulse width of 4t, ts, a beam voltage of 305,9kV and a beam current of 368A, the peak output power has achieved 51.4MW with an efficiency of 45.6% and a gain of 54dB. 展开更多
关键词 50MW s-band klystron High peak power Design ideas
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DEVELOPMENT OF AN S-BAND KLYSTRON WITH BANDWIDTH OF 11%
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作者 WangYong DingYaogen ZhangJian WangShuguo XuMiaoling JiangZhenbo LuXi 《Journal of Electronics(China)》 2004年第6期522-524,共3页
This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS). On the peak p... This letter introduces the design ideas, simulation and test results of an S-band klystron with bandwidth of 11%, which was developed by the Institute of Electronics, Chinese Academy of Sciences (IECAS). On the peak power level of 800 kW, the efficiency of klystron is more than 30%; the gain is more than 41 dB; the equal-driving relative instantaneous bandwidth is over 11%; the average power is larger than 8 kW, and the power fluctuation within bandwidth is less than 1.5 dB. 展开更多
关键词 s-band klystron Bandwidth of 11% Lower peak power
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Suppression of Log-Normal Distributed Weather Clutter Observed by an S-Band Radar
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作者 Shuji Sayama Seishiro Ishii 《Wireless Engineering and Technology》 2013年第3期125-133,共9页
We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, w... We have observed weather clutter containing targets (ships) using an S-band radar with a frequency 3.05 GHz, a beam width 1.8°, and a pulsewidth 0.5 μs. To investigate the weather clutter amplitude statistics, we introduce the Akaike Information Criterion (AIC). We have found that the weather clutter amplitudes obey the log-normal, Weibull, and log-Weibull distributions with the shape parameters of 0.308 to 0.470, 4.42 to 4.51, and 15.91 to 16.44, respectively, for small data within the beam width of an antenna. We have proposed the log-normal/CFAR circuit modified a Cell-Averaging (CA) LOG/CFAR circuit. It is found that weather clutter is suppressed with improvement of 51.58 dB by log-normal/CFAR. As a result, we have showed that weather clutter observed by S-band radar does not obey the Rayleigh distribution and our log-normal/CFAR circuit has an effect on suppression of clutter and detection of target, while conventional LOG/CFAR circuit does not. In addition, if our circuit can be realized, we will have an advantage economically. 展开更多
关键词 CFAR s-band RADAR WEATHER CLUTTER Log-Normal Distribution
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An S-band solid-state radio frequency power amplifier used at Shanghai soft X-ray FEL facility
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作者 Hong-Li Ding Ming-Hua Zhao +2 位作者 Cheng-Cheng Xiao Shao-Peng Zhong Jun-Qiang Zhang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2016年第6期86-92,共7页
In this paper,we present the general design methods and parameter measurements of a 1-k W solidstate radio frequency(RF) power amplifier at 2856 MHz,for the soft X-ray free electron laser facility.Three-stage amplific... In this paper,we present the general design methods and parameter measurements of a 1-k W solidstate radio frequency(RF) power amplifier at 2856 MHz,for the soft X-ray free electron laser facility.Three-stage amplification with a 4-way combination is used.An RF switch module is integrated with the solid-state RF power amplifier to convert the continuous wave(CW) signal into pulse signal,with adjustable pulse width.The power gain is measured at 57.7 d B at 60 d Bm output.The RF phase noise,which is measured by the low-level RF system,is\0.015 degree(RMS),while the pulse frontier jitter is\5 ns. 展开更多
关键词 射频功率放大器 激光装置 自由电子 软X射线 固态 S波段 上海 参数测量
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Microwave Cold Test Debug of an S-Band 2MeV on-Axis Coupling SW Accelerator 被引量:1
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作者 刘婕 柏伟 +3 位作者 陈亚男 许州 黎明 杨兴繁 《Chinese Physics C》 SCIE CAS CSCD 北大核心 2008年第z1期175-177,共3页
This paper presents the model cavity tune and cold test of an S-band 2MeV on-axis coupling SW accelerator. The measurement of the model cavity's frequency,degree of coupling,Q value and on-axis field distribution ... This paper presents the model cavity tune and cold test of an S-band 2MeV on-axis coupling SW accelerator. The measurement of the model cavity's frequency,degree of coupling,Q value and on-axis field distribution are described in detail.In addition,the results of cavity tune and cold test of the accelerating tube are given.The frequency consistency of the accelerator is within±0.3MHz,the coupling degree in the supersaturation state 1.14,the quality factor of the accelerator 12000±200,and the field distribution ratio 1:2.2:2.All the results observed show that the accelerator satisfies the physics design with microwave debugging. 展开更多
关键词 s-band standing wave accelerating tube model cavity
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Raindrop Size Distribution Parameters Retrieved from Guangzhou S-band Polarimetric Radar Observations 被引量:15
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作者 Xiantong LIU Qilin WAN +4 位作者 Hong WANG Hui XIAO Yu ZHANG Tengfei ZHENG Lu FENG 《Journal of Meteorological Research》 SCIE CSCD 2018年第4期571-583,共13页
According to the statistical shape-slope (μ-A) relationship observed for the first time by several 2D-Video-Distro-meters (2DVD) in southern China, a constrained gamma (C-G) model was proposed for the retrieval... According to the statistical shape-slope (μ-A) relationship observed for the first time by several 2D-Video-Distro-meters (2DVD) in southern China, a constrained gamma (C-G) model was proposed for the retrieval of rain drop size distributions (DSDs) from Guangzhou S-band polarimetric radar observations. Two typical precipitation processes were selected to verify the accuracy of the retrieval scheme. The p-A relationship: A = 0.0241μ^2 + 0.867μ + 2.453 was obtained based on the 2DVD observation results from at Huizhou Longmen station, which is a very representat-ive location in the area. Relying on the Guangzhou polarimetric radar measurements of radar reflectivity (ZHH) and differential reflectivity (ZDR), the gamma (F) size distribution parameters (No, μ, and A) can be retrieved by the C-G model retrieval scheme. The results show that the Guangzhou polarimetric radar retrievals of DSDs were close to the 2DVD observations at Guangzhou Maofengshan station. The rain rate, mass mean diameter, and normalized inter-cept parameter of radar retrievals were in good agreement with the 2DVD observations, and the relative errors were less than 10%. The overall accuracy of the retrieval scheme was high. The retrieval scheme has established the rela-tionship between the polarimetric radar measurements and gamma size distribution parameters. It will be helpful to in-depth research and application of the dual-polarization radar data in microphysical precipitation processes analysis, as well as convection-resolved numerical model data assimilation and prediction effect evaluation. 展开更多
关键词 Guangzhou s-band polarimetric radar 2D-Video-Disdrometer raindrop size distribution retrieval MICROPHYSICS
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Design of broadband class-F power amplifier with high-order harmonic suppression for S-band application 被引量:2
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作者 林俊明 章国豪 +3 位作者 郑耀华 李思臻 张志浩 陈思弟 《Journal of Semiconductors》 EI CAS CSCD 2015年第12期119-123,共5页
A broadband class-F power amplifier for an S-band handset device is integrated on a 330.82 mm^3 die using an In Ga /GaAs HBT process. With LC serial harmonic traps immersed into the broadband output matching circuit, ... A broadband class-F power amplifier for an S-band handset device is integrated on a 330.82 mm^3 die using an In Ga /GaAs HBT process. With LC serial harmonic traps immersed into the broadband output matching circuit, good harmonic suppression performance can be achieved. A pure resistive impedance of the matching circuit, but near zero at second and infinite at third harmonic frequency, which enhances the efficiency, is obtained across 1.8–2.5 GHz. Tested with a continuous wave(CW) signal, the PA delivers an output power of 34 dBm and achieves a PAE of 57% at 2 GHz. In addition, excellent harmonic suppression levels of less than –53 dBc across the second to fifth harmonic are obtained. 展开更多
关键词 s-band power amplifier BROADBAND class-F harmonic suppression InGaP/GaAs HBT
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Radio-frequency design and commissioning of a flexible waveguide for high-vacuum S-band applications 被引量:1
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作者 Xiang He Jian-She Cao +2 位作者 Bing-Lin Deng Jing-Dong Liu Nan Gan 《Radiation Detection Technology and Methods》 CSCD 2020年第2期250-254,共5页
Purpose Flexible waveguides,which allow for greater deformation as compared to traditional hard waveguides,are highly useful for simplifying waveguide system assemblies.However,the peak powers of these waveguides have... Purpose Flexible waveguides,which allow for greater deformation as compared to traditional hard waveguides,are highly useful for simplifying waveguide system assemblies.However,the peak powers of these waveguides have been limited to several megawatts in non-vacuum environments.Herein,a novel flexible waveguide was developed for the S-band(2856 MHz)with the aim of facilitating the interconnection of two hard waveguides.Methods The flexible waveguide was composed of brass,and its surface was plated with oxygen-free high-conductivity copper for brazing with stainless steel flanges in a vacuum furnace.By connecting the stainless steel flanges together,it can be applied to a high-vacuum environment.Results The prototype exhibited good measurement results in low-power microwave tests;the results of a 72-h vacuum leak test showed satisfactory vacuum performance as well,and no obvious surface collapse was observed.High-power microwave commissioning was conducted between June and July 2019;the waveguide showed a maximum average power of approximately 2.7 kW.Conclusion Unfortunately,the prototype was damaged after reaching that power level,which indicates the need for further optimization of the fabrication process.From our experiment,it is clear that the flexible waveguide cannot be used in large accelerators because of its average power limit. 展开更多
关键词 s-band Flexible waveguide High vacuum Microwave commissioning
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Passively Q-switched S-band thulium fluoride fiberlaser with multi-walled carbon nanotube
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作者 H.Ahmad S.A.Reduan 《Chinese Optics Letters》 SCIE EI CAS CSCD 2018年第1期43-47,共5页
A stable, passively Q-switched thulium fluoride fiber laser(TFFL) using a multi-walled carbon nanotube(MWCNT)-based saturable absorber(SA) for operation in the S-band region is proposed and demonstrated.The prop... A stable, passively Q-switched thulium fluoride fiber laser(TFFL) using a multi-walled carbon nanotube(MWCNT)-based saturable absorber(SA) for operation in the S-band region is proposed and demonstrated.The proposed TFFL has a central lasing wavelength of 1486.4 nm and an input power range of 87.1–126.6 m W.The output pulses have a repetition rate and pulse width range of 30.1–40.0 k Hz and 9.0–3.2 μs, respectively,with a maximum pulse energy of 28.9 n J. This is the first time, to the author’s knowledge, of the successful demonstration of a passively Q-switched S-band TFFL using an MWCNT-based SA. 展开更多
关键词 MWCNT Passively Q-switched s-band thulium fluoride fiberlaser with multi-walled carbon nanotube SA TFF
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Design and cold test of an S-band waveguide dual circular polarizer
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作者 Jie Lei Xiang He +3 位作者 Guo-Xi Pei Mi Hou Hui Wang Jian-Bing Zhao 《Radiation Detection Technology and Methods》 2017年第2期117-123,共7页
Purpose An S-band dual circular polarizer has been designed and tested with low power in the paper,which will be applied in a spherical cavity pulse compressor.It converts the TE10 mode in rectangular waveguide into t... Purpose An S-band dual circular polarizer has been designed and tested with low power in the paper,which will be applied in a spherical cavity pulse compressor.It converts the TE10 mode in rectangular waveguide into two polarization degenerated TE11 modes in cylindrical waveguide.Methods The general scattering matrix of the dual circular polarizer has been deduced based on the properties of the passive microwave network,which is suitable for the usual 3 dB coupler,as well as the left/right hand circular polarizer.Based on the 3D code software CST,the dual circular polarizer was numerically simulated.Then,two prototypes have been manufactured and tested with the vector network analyzer(VNA).Results The simulation results show that the magnitudes and phase difference of the two TE11 modes are dB and 89.79 degrees,respectively.The cold test results show good agreement with CST simulation.−3.0103/−3.0104 Conclusion The method of analyzing the relationship between the voltage standing wave ratio(VSWR)and the errors of the magnitudes and phase difference of the two TE11 modes was given,which can be used to qualitatively analyze the properties of the circular polarizer.The S-band waveguide dual circular polarizer can be applied in the pulse compressor,phase shifter or other frequency bands. 展开更多
关键词 s-band Dual circular polarizer Scattering matrix Pulse compressor Phase shifter
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RF design of an S-band spherical cavity pulse compressor
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作者 Jie Lei Xiang He +4 位作者 Mi Hou Guan Shu Guo-Xi Pei Xiao-Ping Li Hui Wang 《Radiation Detection Technology and Methods》 2017年第2期57-64,共8页
The pulse compressor plays an important role in accelerators by enhancing the RF peak power.An S-band(2856 MHz)spherical cavity pulse compressor consisting of a special 3 dB coupler and a single spherical energy stora... The pulse compressor plays an important role in accelerators by enhancing the RF peak power.An S-band(2856 MHz)spherical cavity pulse compressor consisting of a special 3 dB coupler and a single spherical energy storage cavity has been developed in Institute of High Energy Physics.The special 3 dB coupler converts the TE10 mode in rectangular waveguide to two polarization degenerated TE11 modes in cylindrical waveguide.It is also a circular polarizer and its general scattering matrix is given for the first time.The magnitude and the phase difference of the two TE11 modes are−3.016,−3.005 dB and 90.02◦in HFSS,while it is−3.01,−3.01 dB and 89.79◦in CST.The simulated S parameters show agreement with the general scattering matrix.The TE114 mode with an unloaded Q factor of 190,000 has been chosen to resonate in the spherical cavity.An energy multiplication factor of 1.75 and a peak power gain of 5.75 were obtained for the whole pulse compressor,which agrees with the design requirements.A good pulse compression performance is also proved by the CST time-domain simulation.In addition,the scheme for tuning and detuning is designed and given in detail.Compared to the traditional SLED type,the spherical cavity pulse compressor uses only one spherical cavity to realize the pulse compression,which makes it compact as a whole. 展开更多
关键词 s-band 3 dB coupler Spherical storage cavity Pulse compressor Circular polarizer
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辽宁弓长岭铁矿床成矿物质来源及磁铁富矿成因探讨
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作者 孙晓辉 汤好书 +1 位作者 陈继宏 白鹏飞 《岩石学报》 SCIE EI CAS 北大核心 2025年第1期289-303,共15页
辽宁鞍本地区是我国最大的BIF型铁矿资源基地,弓长岭铁矿床是该区最大的富铁矿床,其富铁矿成因机制备受关注。目前多认为其为热液改造条带状铁矿(贫矿)而成,但关于热液性质还存在变质热液、混合岩化热液及大气降水等不同认识。在总结前... 辽宁鞍本地区是我国最大的BIF型铁矿资源基地,弓长岭铁矿床是该区最大的富铁矿床,其富铁矿成因机制备受关注。目前多认为其为热液改造条带状铁矿(贫矿)而成,但关于热液性质还存在变质热液、混合岩化热液及大气降水等不同认识。在总结前人研究成果基础上,本研究对辽宁弓长岭铁矿床二矿区条带状铁矿及富铁矿进行了系统的微量元素及Nd-Pb-S同位素分析,结果显示:条带状铁矿及富铁矿中磁铁矿的稀土配分模式一致,成矿物质来源于海水与高温热液混合。条带状铁矿中磁铁矿的ε_(Nd)(t)值变化较大(-6.9~1.5),而富铁矿中磁铁矿相应值(-7.7~-6.1)偏负且集中,指示形成富铁矿的热液流体来自地壳浅部。条带状铁矿中磁铁矿铅同位素μ值介于9.36~10.75,显示壳幔混源的特征;而富铁矿中磁铁矿的μ值(9.58~13.14)较高,指示后期壳源流体交代改造。条带状铁矿中黄铁矿的硫同位素值偏负,且分布集中(-2.08‰~-0.66‰,平均值-1.52‰),而富铁矿中黄铁矿的δ^(34)S同位素值(1.88‰~3.36‰,平均值2.39‰)明显偏重,指示富重硫同位素流体的交代作用。综合推测这种改造条带状铁矿的壳源、富重硫同位素的流体应为变质水与大气降水的混合热液流体,富铁矿为条带状铁矿在古元古代晚期经该混合热液流体改造,发生去硅存铁作用而成。 展开更多
关键词 弓长岭 鞍山群 条带状铁建造 磁铁富矿 Nd-Pb-S同位素
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一种S波段雷达通信电子战多功能宽带DAM的设计
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作者 王才华 方南军 +1 位作者 陈利杰 朱亮 《火控雷达技术》 2024年第1期81-86,共6页
本文创新性地提出了一种S波段多功能宽带DAM,首先介绍了该型DAM的顶层架构设计,接着介绍了各个功能组成模块的设计过程,最后给出了该型DAM的指标实现情况。该型DAM可以分时实现雷达、通信及电子战功能,最大瞬时带宽可达200MHz,支持任意... 本文创新性地提出了一种S波段多功能宽带DAM,首先介绍了该型DAM的顶层架构设计,接着介绍了各个功能组成模块的设计过程,最后给出了该型DAM的指标实现情况。该型DAM可以分时实现雷达、通信及电子战功能,最大瞬时带宽可达200MHz,支持任意波形产生,在多功能综合射频系统中具有良好的应用前景。 展开更多
关键词 多功能 宽带 DAM S波段
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基于频率控制的封闭腔体微波无线输能技术
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作者 敬小炜 景建伟 +1 位作者 闫丽萍 刘长军 《电子学报》 EI CAS CSCD 北大核心 2024年第7期2257-2261,共5页
随着航空航天技术的快速发展,封闭腔体内的无线能量传输(Wireless Power Transmission,WPT)技术开始受到广泛关注.基于频率控制的WPT技术,可实现对电大封闭腔体(103×λ3)内的多方位传感器进行可控和高效的无线充电.电大腔体内的电... 随着航空航天技术的快速发展,封闭腔体内的无线能量传输(Wireless Power Transmission,WPT)技术开始受到广泛关注.基于频率控制的WPT技术,可实现对电大封闭腔体(103×λ3)内的多方位传感器进行可控和高效的无线充电.电大腔体内的电场分布对频率的变化敏感,利用频率变化实现对封闭腔体场分布控制.实验结果表明,在S波段的1 m3腔体最高WPT传输效率为96.6%.设计的宽带整流电路实测整流效率最高为80%,整流效率高于50%的带宽为1.65 GHz.在2.401~2.495 GHz频段实现控制双接收机的不同工作状态,展现其在航空航天器等封闭空间中为传感器无线供电的应用前景. 展开更多
关键词 电大封闭腔体 频率控制 高效率 S波段 微波无线能量传输 整流电路
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天津区域鸟类活动的双偏振天气雷达回波分析
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作者 赵子杭 庄庭 +4 位作者 李建勇 李春 李宗飞 许崇海 史静 《气象》 CSCD 北大核心 2024年第9期1142-1152,共11页
利用2022年6月至2023年3月的宝坻S波段双偏振天气雷达资料,对探测到的天津区域空中生物活动进行分析,结果表明:天津区域空中生物活动存在明显的季节变化和日变化。雷达能够探测到的候鸟迁徙回波集中在2月下旬到11月下旬,其中湿地鸟类活... 利用2022年6月至2023年3月的宝坻S波段双偏振天气雷达资料,对探测到的天津区域空中生物活动进行分析,结果表明:天津区域空中生物活动存在明显的季节变化和日变化。雷达能够探测到的候鸟迁徙回波集中在2月下旬到11月下旬,其中湿地鸟类活动在夏季比较明显,候鸟迁徙活动在2月、11月特别频繁,鸟类回波出现的时刻与日出日落有明显的关联。其中,秋季鸟类活动特征较为明显,回波在反射率产品上呈现明显的类圆形特征,回波强度能达到35 dBz以上;从径向速度产品上可以看出,鸟类飞行时径向速度约在10~27 m·s^(-1);从相关系数(CC)产品上看,鸟类回波的CC整体数值较低,主要分布在0.1~0.8;从差分反射率(ZDR)产品上看,ZDR分布不均匀,最大可达3~5 dB。相比于单偏振天气雷达,S波段双偏振天气雷达对空中生物回波的识别有显著优势。 展开更多
关键词 S波段双偏振天气雷达 鸟类回波 回波强度 相关系数 差分反射率
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利用卷积神经网络开展偏振雷达定量降水估测研究
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作者 蔡康龙 胡志群 +4 位作者 谭浩波 黄锦灿 张伟强 张晶晶 植江玲 《热带气象学报》 CSCD 北大核心 2024年第1期64-74,共11页
利用偏振升级改造后的广州新一代天气雷达(CINRAD/SAD)水平反射率ZH、差分传播相移率KDP、差分反射率因子ZDR和广东佛山219个地面气象自动站雨量数据,形成不同偏振量组合的8个数据集。基于卷积神经网络(CNN),建立雷达定量降水估测网络架... 利用偏振升级改造后的广州新一代天气雷达(CINRAD/SAD)水平反射率ZH、差分传播相移率KDP、差分反射率因子ZDR和广东佛山219个地面气象自动站雨量数据,形成不同偏振量组合的8个数据集。基于卷积神经网络(CNN),建立雷达定量降水估测网络架构QPEnet,并将该架构用于雷达定量降水估测(QPE),评估结果表明:数据集通道数N的增加可降低QPEnet的定量降雨估测的均方根误差(RMSE),并提高相关系数(CORR);对于由ZH形成的数据集Z、Z_1~3 km和Z_6 min,随着通道数N的增加,数据集Z、Z_1~3 km和Z_6 min的性能逐步得到提高,数据集Z_1~3 km和Z_6 min的均方根误差(RMSE)分别是4.71和3.78,比数值集Z分别降低了1.3%和18.7%;数据集Z_1~3 km和Z_6 min的CORR分别是0.82和0.88,比数据集Z分别提高了2.5%和10.0%;对于ZH、KDP和ZDR偏振量组成的数据集里面,数据集Z_ZDR_KDP的拟合性能最好,RMSE为3.97,比数据集Z的RMSE降低了14.6%,CORR是0.86,比数据集Z提高了7.5%;分别对0.6~5 mm、5~10 mm、10~20 mm、20~30 mm、30~40 mm、40~50 mm和50 mm以上的7个降水量级的均方根误差(RMSE)、平均偏差比(MBR)、平均误差(AE)和相对误差(RE)等的统计结果表明,数据集Z_6 min降雨精度最高。 展开更多
关键词 定量降水估测 卷积神经网络 S波段双偏振雷达 测雨精度
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