目的:探讨超微血管成像(superb micro-vascular imaging,SMI)技术对甲状腺影像报告和数据系统(Thyroid Imaging Reporting and Data System,TI-RADS)4类微小结节良恶性的鉴别诊断价值。方法:选择2019年4月—2020年2月安徽医科大学第一...目的:探讨超微血管成像(superb micro-vascular imaging,SMI)技术对甲状腺影像报告和数据系统(Thyroid Imaging Reporting and Data System,TI-RADS)4类微小结节良恶性的鉴别诊断价值。方法:选择2019年4月—2020年2月安徽医科大学第一附属医院收治的98例TI-RADS 4类甲状腺结节患者,共计99个甲状腺实性结节。术前均行SMI检查,观察、分析结节内血流特点并依据Alder血流分级和结节内外血流特点分型。所有甲状腺结节均经手术后病理学检查证实。利用受试者工作特征(receiver operating characteristic,ROC)曲线比较两种血流分型结果对甲状腺微小结节良恶性鉴别是否存在价值,并且计算两者诊断甲状腺癌的灵敏度、特异度、阳性预测值、阴性预测值。结果:共有甲状腺结节99个,其中良性结节52例,恶性结节47例。SMI评价的甲状腺恶性结节Alder血流分级和结节血流特点分型明显高于甲状腺良性结节,差异有统计学意义(χ^(2)=8.69、χ^(2)=37.5,P<0.05)。以Alder血流分级和结节血流特点分型诊断甲状腺癌的曲线下面积(area under curve,AUC)分别为0.596、0.778,差异有统计学意义(Z=2.135,P<0.05)。两种方法诊断甲状腺癌的灵敏度、特异度、阳性预测值、阴性预测值分别为68.09%、61.54%、61.54%、68.09%及76.60%、84.91%、81.82%、80.36%。结论:SMI在对TI-RADS 4类微小甲状腺结节的良恶性鉴别诊断上具有一定价值,且SMI条件下结节内血流为主(Ⅲ型)与Alder血流分级在诊断甲状腺癌上存在差异。展开更多
This paper provides a review of the compact intense electron-beam accelerators (IEBAs) based on liquid pulse forming lines (PFLs) that havebeen developed at the National University of Defense Technology (NUDT) in Chin...This paper provides a review of the compact intense electron-beam accelerators (IEBAs) based on liquid pulse forming lines (PFLs) that havebeen developed at the National University of Defense Technology (NUDT) in China. The history and roadmap of the compact IEBAs used todrive high-power microwave (HPM) devices at NUDT are reviewed. The properties of both de-ionized water and glycerin as energy storagemedia are presented. Research into the breakdown properties of liquid dielectrics and the desire to maximize energy storage have resulted in theinvention of several coaxial PFLs with different electromagnetic structures, which are detailed in this paper. These high energy density liquidPFLs have been used to increase the performance of IEBA subsystems, based on which the SPARK (Single Pulse Accelerator with spark gaps)and HEART (High Energy-density Accelerator with Repetitive Transformer) series of IEBAs were constructed. This paper also discusses howthese compact IEBAs have been used to drive typical HPM devices and concludes by summarizing the associated achievements and theconclusions that can be drawn from the results.展开更多
Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ...Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability.Over the past several years,benefitting from the sustainable innovations in laser technology and the significant progress in materials technology,megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices.Here,we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode,including the mechanism,system architecture,critical technology,and experimental demonstration of the proposed high-power photonic microwave sources.The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.展开更多
Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly p...Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.展开更多
文摘目的:探讨超微血管成像(superb micro-vascular imaging,SMI)技术对甲状腺影像报告和数据系统(Thyroid Imaging Reporting and Data System,TI-RADS)4类微小结节良恶性的鉴别诊断价值。方法:选择2019年4月—2020年2月安徽医科大学第一附属医院收治的98例TI-RADS 4类甲状腺结节患者,共计99个甲状腺实性结节。术前均行SMI检查,观察、分析结节内血流特点并依据Alder血流分级和结节内外血流特点分型。所有甲状腺结节均经手术后病理学检查证实。利用受试者工作特征(receiver operating characteristic,ROC)曲线比较两种血流分型结果对甲状腺微小结节良恶性鉴别是否存在价值,并且计算两者诊断甲状腺癌的灵敏度、特异度、阳性预测值、阴性预测值。结果:共有甲状腺结节99个,其中良性结节52例,恶性结节47例。SMI评价的甲状腺恶性结节Alder血流分级和结节血流特点分型明显高于甲状腺良性结节,差异有统计学意义(χ^(2)=8.69、χ^(2)=37.5,P<0.05)。以Alder血流分级和结节血流特点分型诊断甲状腺癌的曲线下面积(area under curve,AUC)分别为0.596、0.778,差异有统计学意义(Z=2.135,P<0.05)。两种方法诊断甲状腺癌的灵敏度、特异度、阳性预测值、阴性预测值分别为68.09%、61.54%、61.54%、68.09%及76.60%、84.91%、81.82%、80.36%。结论:SMI在对TI-RADS 4类微小甲状腺结节的良恶性鉴别诊断上具有一定价值,且SMI条件下结节内血流为主(Ⅲ型)与Alder血流分级在诊断甲状腺癌上存在差异。
基金This work was supported by the National Natural Science Foundation of China under Grant No.51677190the Hunan Provincial Natural Science Foundation of China under Grant No.2017JJ1005.
文摘This paper provides a review of the compact intense electron-beam accelerators (IEBAs) based on liquid pulse forming lines (PFLs) that havebeen developed at the National University of Defense Technology (NUDT) in China. The history and roadmap of the compact IEBAs used todrive high-power microwave (HPM) devices at NUDT are reviewed. The properties of both de-ionized water and glycerin as energy storagemedia are presented. Research into the breakdown properties of liquid dielectrics and the desire to maximize energy storage have resulted in theinvention of several coaxial PFLs with different electromagnetic structures, which are detailed in this paper. These high energy density liquidPFLs have been used to increase the performance of IEBA subsystems, based on which the SPARK (Single Pulse Accelerator with spark gaps)and HEART (High Energy-density Accelerator with Repetitive Transformer) series of IEBAs were constructed. This paper also discusses howthese compact IEBAs have been used to drive typical HPM devices and concludes by summarizing the associated achievements and theconclusions that can be drawn from the results.
基金supported in part by the National Natural Science Foundation of China(Nos.62071477 and 62101577)the Natural Science Foundation of Hunan Province(No.2021JJ40660)。
文摘Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability.Over the past several years,benefitting from the sustainable innovations in laser technology and the significant progress in materials technology,megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices.Here,we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode,including the mechanism,system architecture,critical technology,and experimental demonstration of the proposed high-power photonic microwave sources.The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.
文摘Narrowband microwave generation with tuneable frequency is demonstrated by illuminating a photoconductive semiconductor switch(PCSS)with a burst-mode fibre laser.The whole system is composed of a high-power linearly polarized burst-mode pulsed fibre laser and a linear-state PCSS.To obtain a high-performance microwave signal,a desired envelope of burst is necessary and a pulse pre-compensation technique is adopted to avoid envelope distortion induced by the gain-saturation effect.Resulting from the technique,homogenous peak power distribution in each burst is ensured.The maximum energy of the laser burst pulse reaches 200μJ with a burst duration of 100 ns at the average power of 10 W,corresponding to a peak power of 4 kW.When the PCSS is illuminated by the burst-mode fibre laser,narrowband microwave generation with tuneable frequency(0.80-1.12 GHz)is obtained with a power up to 300 W.To the best of the authors’knowledge,it is the first demonstration of frequency-tuneable narrowband microwave generation based on a fibre laser.The high-power burst-mode fibre laser reported here has great potential for generating high-power arbitrary microwave signals for a great deal of applicable demands such as smart adaptive radar and intelligent high-power microwave systems.
