A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interac...A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interaction between optical signal and ultrasound wave,exhibiting a high sensitivity of 3.5 mV/kPa,which is approximately 10 times higher than the single-mode fiber sensor.Meanwhile,a phase feedback stabilization module is introduced into the coherent demodulation system for long-term stable measurement.In addition,a photoacoustic tomography experiment with the microfiber ultrasound sensor is implemented to verify the excellent performance on imaging,with the depth of 12 mm,the highest lateral resolution of 65μm and axial resolution of 250μm,respectively.The highly sensitive microfiber ultrasound sensor provides a competitive alternative for various applications,such as industrial non-destructive testing,biomedical ultrasound and photoacoustic imaging.展开更多
Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducer...Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.展开更多
Fish finders have already been widely available in the fishing market for a number of years.However,the sizes of these fish finders are too big and their prices are expensive to suit for the research of robotic fish o...Fish finders have already been widely available in the fishing market for a number of years.However,the sizes of these fish finders are too big and their prices are expensive to suit for the research of robotic fish or mini-submarine.The goal of this research is to propose a low-cost fish detector and classifier which suits for underwater robot or submarine as a proximity sensor. With some pre-condition in hardware and algorithms,the experimental results show that the proposed design has good per- formance,with a detection rate of 100 % and a classification rate of 94 %.Both the existing type of fish and the group behavior can be revealed by statistical interpretations such as hovering passion and sparse swimming mode.展开更多
In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1</span><span style="font-family:Verdan...In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">3. To accelerate and decide further decommissioning steps of the FDNPP, it is crucial to obtain realistic information of the debris and localize contaminated water leakage from PCV. Due to high radiation and dark environment inside the PCV, investigating instruments and techniques should necessarily to meet specification of radiation resistance, waterproofness, dust resistance and so on. This study focuses on development of ultrasonic measurement system using a couple of sectorial array sensors to localize contaminated water leakage and visualize shape of object that repre</span><span style="font-family:Verdana;">- </span><span style="font-family:Verdana;">senting fuel debris, simultaneously. In this study, Total Focusing Method</span><span style="font-family:Verdana;"> (TFM) and Ultrasonic Velocity Profiler (UVP) methods are considered to visualize object shape and flow pattern around it, respectively. To demonstrate applicability and reliability of developed measurement system with sectorial array sensors, a mock-up experiment result</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">of simulated water leakage and fuel debris shape were discussed in this paper.展开更多
变压器能否稳定工作直接关系到变电站是否安全运行,其工作重心是检测出变压器局部放电产生的超声波信号。介绍了一种光纤F-P腔传感器,并在此基础上搭建了调制解调系统,分别通过对无超声波源、有超声波源和浸入变压器油中3种情况进行了...变压器能否稳定工作直接关系到变电站是否安全运行,其工作重心是检测出变压器局部放电产生的超声波信号。介绍了一种光纤F-P腔传感器,并在此基础上搭建了调制解调系统,分别通过对无超声波源、有超声波源和浸入变压器油中3种情况进行了实验测试,并在距离超声波源20,40,60,80,90,100 cm处进行了损耗特性测试,测试结果表明:此传感器受外界噪声干扰较小,且在变压器油中能实时地检测出超声波信号,精度高,损耗度为25.8 m V/cm,符合传感器在油浸式变压器中持续稳定工作的条件。当变压器出现故障时,能够及时发现问题,保证变压器安全运行。展开更多
基金financial supports from National Natural Science Foundation of China (NSFC)(No.61922033)Foundation for Innovative Research Groups of Hubei Province of China (2018CFA004)Innovation Fund of WNLO
文摘A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interaction between optical signal and ultrasound wave,exhibiting a high sensitivity of 3.5 mV/kPa,which is approximately 10 times higher than the single-mode fiber sensor.Meanwhile,a phase feedback stabilization module is introduced into the coherent demodulation system for long-term stable measurement.In addition,a photoacoustic tomography experiment with the microfiber ultrasound sensor is implemented to verify the excellent performance on imaging,with the depth of 12 mm,the highest lateral resolution of 65μm and axial resolution of 250μm,respectively.The highly sensitive microfiber ultrasound sensor provides a competitive alternative for various applications,such as industrial non-destructive testing,biomedical ultrasound and photoacoustic imaging.
基金This work was supported by the National Natural Science Foundation of China(61775083,61705082,61805102,and 61860206002)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)Guangzhou Science and Technology Plan(201904020032).
文摘Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.
基金This research was fund by Fundamental Research Fund Program from Indonesia Ministry of Research and Technology in years 2007. ID Number: RD-2009-2550.
文摘Fish finders have already been widely available in the fishing market for a number of years.However,the sizes of these fish finders are too big and their prices are expensive to suit for the research of robotic fish or mini-submarine.The goal of this research is to propose a low-cost fish detector and classifier which suits for underwater robot or submarine as a proximity sensor. With some pre-condition in hardware and algorithms,the experimental results show that the proposed design has good per- formance,with a detection rate of 100 % and a classification rate of 94 %.Both the existing type of fish and the group behavior can be revealed by statistical interpretations such as hovering passion and sparse swimming mode.
文摘In Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, the fuel debris formed in the Reactor Pressure Vessel (RPV) and Primary Containment Vessel (PCV) at Unit 1</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">3. To accelerate and decide further decommissioning steps of the FDNPP, it is crucial to obtain realistic information of the debris and localize contaminated water leakage from PCV. Due to high radiation and dark environment inside the PCV, investigating instruments and techniques should necessarily to meet specification of radiation resistance, waterproofness, dust resistance and so on. This study focuses on development of ultrasonic measurement system using a couple of sectorial array sensors to localize contaminated water leakage and visualize shape of object that repre</span><span style="font-family:Verdana;">- </span><span style="font-family:Verdana;">senting fuel debris, simultaneously. In this study, Total Focusing Method</span><span style="font-family:Verdana;"> (TFM) and Ultrasonic Velocity Profiler (UVP) methods are considered to visualize object shape and flow pattern around it, respectively. To demonstrate applicability and reliability of developed measurement system with sectorial array sensors, a mock-up experiment result</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">of simulated water leakage and fuel debris shape were discussed in this paper.
文摘变压器能否稳定工作直接关系到变电站是否安全运行,其工作重心是检测出变压器局部放电产生的超声波信号。介绍了一种光纤F-P腔传感器,并在此基础上搭建了调制解调系统,分别通过对无超声波源、有超声波源和浸入变压器油中3种情况进行了实验测试,并在距离超声波源20,40,60,80,90,100 cm处进行了损耗特性测试,测试结果表明:此传感器受外界噪声干扰较小,且在变压器油中能实时地检测出超声波信号,精度高,损耗度为25.8 m V/cm,符合传感器在油浸式变压器中持续稳定工作的条件。当变压器出现故障时,能够及时发现问题,保证变压器安全运行。
