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RSS2023 Vol. 47, No. 4
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2023, 47(4): 439-453.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.001
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Abstract:
Compared with other cooled infrared detector material systems, type-Ⅱ superlattice (T2SL) has the characteristics of low cost, high uniformity, good process compatibility, flexible wavelength adjustability and lower Auger recombination rates. As a commonly used and relatively mature energy band structure simulation technology, the k · p method has the characteristics of high computational accuracy and saving computing resources, and has received widespread attention in the simulation of T2SL. The progress of simulation of mid-wave, long-wave, and very-long-wave T2SL infrared detectors was reviewed, and the development process of the k · p method was summarized, as well as the progress and role of the method in the simulation of T2SL infrared detectors, to more intuitively demonstrate the accuracy and convenience of the k · p method in superlattice simulation work. The dark current mechanisms, quantum efficiency, absorption spectra, and other properties of T2SL detectors were discussed with emphasis on the prospect of research and application of T2SL infrared detectors. The k · p method under the approximation of the envelope function can be used to perform accurate theoretical analysis and simulation calculations on the band structure and electronic properties of superlattice materials.
Compared with other cooled infrared detector material systems, type-Ⅱ superlattice (T2SL) has the characteristics of low cost, high uniformity, good process compatibility, flexible wavelength adjustability and lower Auger recombination rates. As a commonly used and relatively mature energy band structure simulation technology, the k · p method has the characteristics of high computational accuracy and saving computing resources, and has received widespread attention in the simulation of T2SL. The progress of simulation of mid-wave, long-wave, and very-long-wave T2SL infrared detectors was reviewed, and the development process of the k · p method was summarized, as well as the progress and role of the method in the simulation of T2SL infrared detectors, to more intuitively demonstrate the accuracy and convenience of the k · p method in superlattice simulation work. The dark current mechanisms, quantum efficiency, absorption spectra, and other properties of T2SL detectors were discussed with emphasis on the prospect of research and application of T2SL infrared detectors. The k · p method under the approximation of the envelope function can be used to perform accurate theoretical analysis and simulation calculations on the band structure and electronic properties of superlattice materials.
2023, 47(4): 454-458.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.002
Abstract:
To obtain wavelength-tunable pulse cylindrical vector beam, a linear cavity mode-locked doped-Yb fiber laser was experimentally constructed by using a chirped fiber grating and a semiconductor saturable absorption mirror. A long-period fiber grating was inserted into the cavity to serve as mode conversion device. The results show that when the mode-locked fiber laser operates at 1060.72 nm, the spectral width, slope efficiency, pulse width, fundamental repetition frequency, signal-to-noise ratio, and the cylindrical vector beam mode purity is 0.22 nm, 8.6%, of 10.9 ps, 18.66 MHz, 65 dB, >97%, respectively. Besides, the operating wavelength of the mode-locked fiber laser can be continuously tuned from 1060.72 nm to 1066.04 nm due to the changing of the cavity loss by adjusting the polarization controller. This study may provide an important reference for the development of wavelength-tunable pulsed cylindrical vector beam fiber laser.
To obtain wavelength-tunable pulse cylindrical vector beam, a linear cavity mode-locked doped-Yb fiber laser was experimentally constructed by using a chirped fiber grating and a semiconductor saturable absorption mirror. A long-period fiber grating was inserted into the cavity to serve as mode conversion device. The results show that when the mode-locked fiber laser operates at 1060.72 nm, the spectral width, slope efficiency, pulse width, fundamental repetition frequency, signal-to-noise ratio, and the cylindrical vector beam mode purity is 0.22 nm, 8.6%, of 10.9 ps, 18.66 MHz, 65 dB, >97%, respectively. Besides, the operating wavelength of the mode-locked fiber laser can be continuously tuned from 1060.72 nm to 1066.04 nm due to the changing of the cavity loss by adjusting the polarization controller. This study may provide an important reference for the development of wavelength-tunable pulsed cylindrical vector beam fiber laser.
2023, 47(4): 459-462.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.003
Abstract:
Gas insulated switchgear (GIS) is widely used in the construction of State Grid Substations, and it is usually necessary to do insulation withstand voltage tests before GIS is put into production. To locate faulty equipment on site, according to the practical application environment, a fast and effective method was presented to locate the fault equipment in GIS insulation withstand voltage test by using distributed acoustic sensing (DAS) system. Through the back Rayleigh scattering signal of the optical fiber itself, the phase heterodyne was adopted phase-sensitive optical time-domain reflectometer (φ-OTDR) multi wavelength multi path modulation and demodulation method, which can visually and real-time monitor the optical fiber vibration signals at different positions of the metal shell of the GIS system to reduce the test blind spots. The experimental test results show that, fast and accurate positioning of fault equipment in GIS can be realized with the developed DAS system, and the positioning accuracy can reach within 3 m. It has a good reference value for timely troubleshooting and maintenance of GIS field faults and ensuring the safe operation of power equipment.
Gas insulated switchgear (GIS) is widely used in the construction of State Grid Substations, and it is usually necessary to do insulation withstand voltage tests before GIS is put into production. To locate faulty equipment on site, according to the practical application environment, a fast and effective method was presented to locate the fault equipment in GIS insulation withstand voltage test by using distributed acoustic sensing (DAS) system. Through the back Rayleigh scattering signal of the optical fiber itself, the phase heterodyne was adopted phase-sensitive optical time-domain reflectometer (φ-OTDR) multi wavelength multi path modulation and demodulation method, which can visually and real-time monitor the optical fiber vibration signals at different positions of the metal shell of the GIS system to reduce the test blind spots. The experimental test results show that, fast and accurate positioning of fault equipment in GIS can be realized with the developed DAS system, and the positioning accuracy can reach within 3 m. It has a good reference value for timely troubleshooting and maintenance of GIS field faults and ensuring the safe operation of power equipment.
2023, 47(4): 463-468.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.004
Abstract:
In order to investigate the effect of WC mass fraction on the properties of Ni60 powder laser cladding coating, the WC and Ni60 composite coating was prepared on Q235 carbon tool steel by laser cladding technology, and the theoretical analysis and experimental verification were carried out. The date of geometrical morphology, dilution rate, microstructure and hardness of cladding layer were obtained. The results show that, after adding WC, the coating has good appearance and the hardness of coating can be improved obviously. The dilution rate increased firstly and then decreased with the increase of WC mass fraction. When the WC mass fraction is 0.4, the appropriate powder ratio can not only ensure the dense microstructure and uniform dendrite size, but also avoid the influence of particles and pores on the coating quality, and ensure the fusion of two coating materials and the overall hardness of the coating. The results of this study have a certain guiding role for the preparation of Ni-based composite with WC added by laser melting coating.
In order to investigate the effect of WC mass fraction on the properties of Ni60 powder laser cladding coating, the WC and Ni60 composite coating was prepared on Q235 carbon tool steel by laser cladding technology, and the theoretical analysis and experimental verification were carried out. The date of geometrical morphology, dilution rate, microstructure and hardness of cladding layer were obtained. The results show that, after adding WC, the coating has good appearance and the hardness of coating can be improved obviously. The dilution rate increased firstly and then decreased with the increase of WC mass fraction. When the WC mass fraction is 0.4, the appropriate powder ratio can not only ensure the dense microstructure and uniform dendrite size, but also avoid the influence of particles and pores on the coating quality, and ensure the fusion of two coating materials and the overall hardness of the coating. The results of this study have a certain guiding role for the preparation of Ni-based composite with WC added by laser melting coating.
Research progress in modeling the optimization of process parameters of laser additive manufacturing
2023, 47(4): 469-479.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.005
Abstract:
The formation quality and performance of the forming parts are directly affected by the process parameters of laser additive manufacturing. Thus optimizing the process parameters is the most effective way to achieve forming quality regulation. For the prediction of forming quality and the optimization of process parameters, it is extremely important to establish a model describing the relationships between accurate high-precision process parameters and formation quality. In this paper, the method of modeling the optimization of process parameters of laser additive manufacturing were summarized and reviewed, the development of the status quo of process system was also analyzed. The principles, advantages, and disadvantages of the method have been discussed for modeling the optimization of process parameters. Finally, the laser additive manufacturing process optimization modeling research has been prospected.
The formation quality and performance of the forming parts are directly affected by the process parameters of laser additive manufacturing. Thus optimizing the process parameters is the most effective way to achieve forming quality regulation. For the prediction of forming quality and the optimization of process parameters, it is extremely important to establish a model describing the relationships between accurate high-precision process parameters and formation quality. In this paper, the method of modeling the optimization of process parameters of laser additive manufacturing were summarized and reviewed, the development of the status quo of process system was also analyzed. The principles, advantages, and disadvantages of the method have been discussed for modeling the optimization of process parameters. Finally, the laser additive manufacturing process optimization modeling research has been prospected.
2023, 47(4): 480-484.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.006
Abstract:
In order to quantitatively study the damage process of gallium arsenide(GaAs) wafer under infrared laser irradiation, a 1080 nm fiber laser was used as the light source. The scattered laser beam from both front surface and back surface of the wafer was collected. Then the damage process can be monitored in real time according to the scattering signal. A finite element model was established to study the evolution of the temperature field and scattering signal. The three regions of scattering signal corresponded to extrinsic absorption region, intrinsic absorption region and surface damage region, respectively. When the laser power density was 1.8 kW/cm2 and the irradiation time was 193 ms, slip lines can be observed on the initial damaged surface. The element content of the damage center was analyzed, and the oxygen element content increased greatly. These results indicated that thermal stress and oxidation reaction were the main damage mechanisms of GaAs. This study can provide theoretical and experimental basis for further research on temperature rise, thermal stress and ablation of GaAs wafer during laser irradiation.
In order to quantitatively study the damage process of gallium arsenide(GaAs) wafer under infrared laser irradiation, a 1080 nm fiber laser was used as the light source. The scattered laser beam from both front surface and back surface of the wafer was collected. Then the damage process can be monitored in real time according to the scattering signal. A finite element model was established to study the evolution of the temperature field and scattering signal. The three regions of scattering signal corresponded to extrinsic absorption region, intrinsic absorption region and surface damage region, respectively. When the laser power density was 1.8 kW/cm2 and the irradiation time was 193 ms, slip lines can be observed on the initial damaged surface. The element content of the damage center was analyzed, and the oxygen element content increased greatly. These results indicated that thermal stress and oxidation reaction were the main damage mechanisms of GaAs. This study can provide theoretical and experimental basis for further research on temperature rise, thermal stress and ablation of GaAs wafer during laser irradiation.
2023, 47(4): 485-491.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.007
Abstract:
In order to avoid the problems of complicated steps and noise interference of traditional holographic reconstruction methods, an improved semantic segmentation U-Net network was used for super-resolution reconstruction of holograms. Firstly, a novel end-to-end neural network was introduced to fully acquire more semantic information of images and to enhance the performance of network learning. Secondly, the efficient channel attention (ECA) of deep neural convolutional network was added to improve the ability of focusing on details in the holograms, and to further improve the accuracy of the network. The leaky rectified linear units (LeakyReLU) was used as the activation function to accelerate the network convergence. Using the low resolution holograms of blood cells and chicken blood cells for training, the super-resolution reconstruction intensity and phase map were obtained. The results show that the improved network can quickly reconstruct the phase and intensity images with rich details, clear edge texture and flat background. The structure similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR) of the blood cell intensity reconstruction images are 0.9613 and 27.38, respectively. Meanwhile, the holograms of different scales can be reconstructed. This study provides a reference for using deep learning to improve the quality of holograms.
In order to avoid the problems of complicated steps and noise interference of traditional holographic reconstruction methods, an improved semantic segmentation U-Net network was used for super-resolution reconstruction of holograms. Firstly, a novel end-to-end neural network was introduced to fully acquire more semantic information of images and to enhance the performance of network learning. Secondly, the efficient channel attention (ECA) of deep neural convolutional network was added to improve the ability of focusing on details in the holograms, and to further improve the accuracy of the network. The leaky rectified linear units (LeakyReLU) was used as the activation function to accelerate the network convergence. Using the low resolution holograms of blood cells and chicken blood cells for training, the super-resolution reconstruction intensity and phase map were obtained. The results show that the improved network can quickly reconstruct the phase and intensity images with rich details, clear edge texture and flat background. The structure similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR) of the blood cell intensity reconstruction images are 0.9613 and 27.38, respectively. Meanwhile, the holograms of different scales can be reconstructed. This study provides a reference for using deep learning to improve the quality of holograms.
2023, 47(4): 492-499.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.008
Abstract:
In order to accurately recover the complete shape of the measured object with partial occlusion, a system for light field 3-D imaging based on multi-line structured light marking was proposed and a structured light field 3-D imaging method based on the Hough transform was proposed for the image processing problem in this system. The extracted sub-pixel fringe center coordinates were used to Hough transform, then the voting distribution in the Hough parameter space was analyzed, and adaptive range voting and adaptive window strategies were designed. Consequently, the parameters of multiple straight lines in the epipolar plane image can be accurately determined by the proposed method, which does not need to encode the fringe level. The experimental results show that the mean deviation and standard deviation of the fitted plane are 0.0096 mm and 0.0074 mm respectively. The complete shape of measured object is accurately obtained, which utilities the occlusion of different sub-aperture images is inconsistent in light field imaging. The result is helpful for solving the occlusion problem in the 3-D measurement process, and this work provides a reference for the measurement method to obtain complete and efficient 3-D data.
In order to accurately recover the complete shape of the measured object with partial occlusion, a system for light field 3-D imaging based on multi-line structured light marking was proposed and a structured light field 3-D imaging method based on the Hough transform was proposed for the image processing problem in this system. The extracted sub-pixel fringe center coordinates were used to Hough transform, then the voting distribution in the Hough parameter space was analyzed, and adaptive range voting and adaptive window strategies were designed. Consequently, the parameters of multiple straight lines in the epipolar plane image can be accurately determined by the proposed method, which does not need to encode the fringe level. The experimental results show that the mean deviation and standard deviation of the fitted plane are 0.0096 mm and 0.0074 mm respectively. The complete shape of measured object is accurately obtained, which utilities the occlusion of different sub-aperture images is inconsistent in light field imaging. The result is helpful for solving the occlusion problem in the 3-D measurement process, and this work provides a reference for the measurement method to obtain complete and efficient 3-D data.
2023, 47(4): 500-505.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.009
Abstract:
In order to solve the natural narrow bandwidth of wide-bandwidth optical source with Er3+-doped fiber amplified spontaneous emission, the configuration of double-pass, backward pumped, and connected unpumped-fiber was proposed to eliminate the influence of pump source and broaden its bandwidth. The numerical simulation and experiment were carried out. The influence of Er3+-doped fiber length and reflection coefficient of fiber reflect mirror on the optical spectrum was analyzed in detail. The optimization effect of unpumped Er3+-doped fiber on the amplified spontaneous emission output spectrum was studied. The results show that, with increasing the length of pumped fiber, the C-band of the amplified spontaneous emission spectrum decreases slowly, and L-band raises. When the reflect coefficient of mirror increases, the bandwidth of amplified spontaneous emission was broadened correspondingly. The bandwidth of amplified spontaneous emission is 50.31 nm when the pumped and unpumped fiber is 6 m and 2 m respectively, which is improved 44 nm. All the results obtained could provide support for the design of wide-band optical source.
In order to solve the natural narrow bandwidth of wide-bandwidth optical source with Er3+-doped fiber amplified spontaneous emission, the configuration of double-pass, backward pumped, and connected unpumped-fiber was proposed to eliminate the influence of pump source and broaden its bandwidth. The numerical simulation and experiment were carried out. The influence of Er3+-doped fiber length and reflection coefficient of fiber reflect mirror on the optical spectrum was analyzed in detail. The optimization effect of unpumped Er3+-doped fiber on the amplified spontaneous emission output spectrum was studied. The results show that, with increasing the length of pumped fiber, the C-band of the amplified spontaneous emission spectrum decreases slowly, and L-band raises. When the reflect coefficient of mirror increases, the bandwidth of amplified spontaneous emission was broadened correspondingly. The bandwidth of amplified spontaneous emission is 50.31 nm when the pumped and unpumped fiber is 6 m and 2 m respectively, which is improved 44 nm. All the results obtained could provide support for the design of wide-band optical source.
2023, 47(4): 506-512.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.010
Abstract:
In order to solve the problem of poor mechanical properties of laser cladding In718 alloy, different scanning speeds were selected to carry out laser remelting treatment of the cladding layer. Optical microscope, scanning electron microscope and energy dispersive spectrometer were used to observe the microstructure and characteristics and to detect the composition of different phases. The influence of microsegregation on the microstructure was then analyzed. The microhardness and tensile strength of the coating were tested by mechanical testing equipment. The results show that the Laves phase is mainly caused by the segregation of Nb and Mo elements. Compared with the non-remelted coating, the pores of the remelted coating are significantly reduced, and different remelting scanning speeds have different effects on the structure and properties. The Laves phase volume fraction of four coatings respectively decreased from 34.1% to 24.6%, 16.7%, and 19.6%, the average hardness respectively increased from 250.3 HV to 261.5 HV, 276.9 HV, and 268.0 HV. The tensile strength respectively increased from 678 MPa to 728 MPa, 879 MPa, and 808 MPa. However, the effect of remelted coating on elongation is not obvious. The optimum remelting scanning speed is 15 mm/s, which has the lowest Laves phase content and the highest average microhardness and tensile strength. Laser remelting can effectively improve the morphology of the cladding layer, reduce the porosity, reduce or inhibit the precipitation of Laves phase. Reducing the Laves phase to improve the mechanical properties of In718 alloy. This research establishes a theoretical foundation for the subsequent remanufacturing of centrifugal cast ductile iron pipes molds.
In order to solve the problem of poor mechanical properties of laser cladding In718 alloy, different scanning speeds were selected to carry out laser remelting treatment of the cladding layer. Optical microscope, scanning electron microscope and energy dispersive spectrometer were used to observe the microstructure and characteristics and to detect the composition of different phases. The influence of microsegregation on the microstructure was then analyzed. The microhardness and tensile strength of the coating were tested by mechanical testing equipment. The results show that the Laves phase is mainly caused by the segregation of Nb and Mo elements. Compared with the non-remelted coating, the pores of the remelted coating are significantly reduced, and different remelting scanning speeds have different effects on the structure and properties. The Laves phase volume fraction of four coatings respectively decreased from 34.1% to 24.6%, 16.7%, and 19.6%, the average hardness respectively increased from 250.3 HV to 261.5 HV, 276.9 HV, and 268.0 HV. The tensile strength respectively increased from 678 MPa to 728 MPa, 879 MPa, and 808 MPa. However, the effect of remelted coating on elongation is not obvious. The optimum remelting scanning speed is 15 mm/s, which has the lowest Laves phase content and the highest average microhardness and tensile strength. Laser remelting can effectively improve the morphology of the cladding layer, reduce the porosity, reduce or inhibit the precipitation of Laves phase. Reducing the Laves phase to improve the mechanical properties of In718 alloy. This research establishes a theoretical foundation for the subsequent remanufacturing of centrifugal cast ductile iron pipes molds.
2023, 47(4): 513-519.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.011
Abstract:
In order to investigate the material removal mechanism, technological rules, and optimization of technological parameters, experimental investigations of laser drilling on polystyrene(PS) with single-pulse and multi-pulse nanosecond solid-state laser at 266 nm based on the single factor experiment and orthogonal experiment method were carried out. The material removal mechanism was analyzed, and the relationship between the diameter and depth of the micropore and the number of laser pulses, the laser pulse energy and the defocusing distance was obtained. As well as an optimized combination of process parameters meeting the requirements was acquired. The experimental results show that when the laser pulse energy is 0.110 mJ, the micropore with regular shape, better roundness, and smaller recast layer was obtained; when the laser pulse energy is 0.500 mJ, the shape and roundness of micropore becomes worse, and the width of recast layer becomes larger at the same time. During the multi-pulse drilling, no recast layer is present at the entrance of the through-hole with the laser pulse energy of 0.040 mJ, and the removal mechanism is mainly photochemical. With the laser pulse energy of 0.390 mJ, the recast layer is more visible at the entrance of the through-hole and over-ablation occurs at the entrance edge, the removal mechanism is mainly photothermal. Laser pulse energy and defocusing distance have a large effect on the hole diameter, and the number of laser pulses and positive defocusing distance have a large effect on the hole depth. The optimized combination of parameters obtained from the orthogonal experiments that micropores of good quality can be produced when the number of laser pulses is 50, laser pulse energy is 0.021 mJ and defocusing distance is 0 μm. This investigation provides a reference for 266 nm nanosecond laser processing of polystyrene target.
In order to investigate the material removal mechanism, technological rules, and optimization of technological parameters, experimental investigations of laser drilling on polystyrene(PS) with single-pulse and multi-pulse nanosecond solid-state laser at 266 nm based on the single factor experiment and orthogonal experiment method were carried out. The material removal mechanism was analyzed, and the relationship between the diameter and depth of the micropore and the number of laser pulses, the laser pulse energy and the defocusing distance was obtained. As well as an optimized combination of process parameters meeting the requirements was acquired. The experimental results show that when the laser pulse energy is 0.110 mJ, the micropore with regular shape, better roundness, and smaller recast layer was obtained; when the laser pulse energy is 0.500 mJ, the shape and roundness of micropore becomes worse, and the width of recast layer becomes larger at the same time. During the multi-pulse drilling, no recast layer is present at the entrance of the through-hole with the laser pulse energy of 0.040 mJ, and the removal mechanism is mainly photochemical. With the laser pulse energy of 0.390 mJ, the recast layer is more visible at the entrance of the through-hole and over-ablation occurs at the entrance edge, the removal mechanism is mainly photothermal. Laser pulse energy and defocusing distance have a large effect on the hole diameter, and the number of laser pulses and positive defocusing distance have a large effect on the hole depth. The optimized combination of parameters obtained from the orthogonal experiments that micropores of good quality can be produced when the number of laser pulses is 50, laser pulse energy is 0.021 mJ and defocusing distance is 0 μm. This investigation provides a reference for 266 nm nanosecond laser processing of polystyrene target.
2023, 47(4): 520-526.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.012
Abstract:
In order to realize the simultaneous measurement of magnetic field and temperature, a Mach-Zehnder interferometer based on sphere-thin core fiber-sphere sensing structure was fabricated. The double parameter sensing was studied by using magnetic fluid as the sensing structure external environment. When the external magnetic field and temperature change, the refractive index of magnetic fluid changes regularly, and the magnetic field and temperature can be measured at the same time. But the extinction ratio of the structure is poor, so a spherical-multi mode fiber-thin core fiber-sphere sensor structure is improved. The results show that the magnetic field and temperature sensitivity of the sphere-thin core fiber-sphere sensing structure obtained by single-peak demodulation are -0.0967 nm/mT and 0.0667 nm/℃, respectively. The improved sphere-multi mode fiber-thin core fiber-sphere structure has a good interference effect, and the magnetic field and temperature sensitivity are 0.1267 nm/mT and -0.1213 nm/℃, respectively. It has the characteristics of low cost, high sensitivity, noise resistance and good application. The research can provide reference for the design of magnetic field and temperature double parameter sensor.
In order to realize the simultaneous measurement of magnetic field and temperature, a Mach-Zehnder interferometer based on sphere-thin core fiber-sphere sensing structure was fabricated. The double parameter sensing was studied by using magnetic fluid as the sensing structure external environment. When the external magnetic field and temperature change, the refractive index of magnetic fluid changes regularly, and the magnetic field and temperature can be measured at the same time. But the extinction ratio of the structure is poor, so a spherical-multi mode fiber-thin core fiber-sphere sensor structure is improved. The results show that the magnetic field and temperature sensitivity of the sphere-thin core fiber-sphere sensing structure obtained by single-peak demodulation are -0.0967 nm/mT and 0.0667 nm/℃, respectively. The improved sphere-multi mode fiber-thin core fiber-sphere structure has a good interference effect, and the magnetic field and temperature sensitivity are 0.1267 nm/mT and -0.1213 nm/℃, respectively. It has the characteristics of low cost, high sensitivity, noise resistance and good application. The research can provide reference for the design of magnetic field and temperature double parameter sensor.
2023, 47(4): 527-533.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.013
Abstract:
In order to reduce the low accuracy of the prediction model of soluble solid content caused by the size difference of gongpear, a general size model was proposed. Near-infrared diffuse reflection spectroscopy and partial least squares regression algorithm modeling method of the near-infrared spectrum were adopted, and the theoretical analysis and experimental verification were respectively carried out. Gongpear soluble solids content of data were obtained by a local size prediction model of the small fruit, middle fruit and big fruit size grades and a universal size model with different size grade. The results show that, the local size model is good at predicting the soluble solid content of gongpears with its own grade, but poor at predicting other grades. The correlation coefficient were 0.892, 0.937, 0.889 and root mean square error of small fruit, medium fruit and large fruit predicted by the general model were 0.524, 0.417, 0.551. The general size model could reduce the adverse effects of size difference and was suitable for the determination of soluble solid content of gongpear with different size grades.
In order to reduce the low accuracy of the prediction model of soluble solid content caused by the size difference of gongpear, a general size model was proposed. Near-infrared diffuse reflection spectroscopy and partial least squares regression algorithm modeling method of the near-infrared spectrum were adopted, and the theoretical analysis and experimental verification were respectively carried out. Gongpear soluble solids content of data were obtained by a local size prediction model of the small fruit, middle fruit and big fruit size grades and a universal size model with different size grade. The results show that, the local size model is good at predicting the soluble solid content of gongpears with its own grade, but poor at predicting other grades. The correlation coefficient were 0.892, 0.937, 0.889 and root mean square error of small fruit, medium fruit and large fruit predicted by the general model were 0.524, 0.417, 0.551. The general size model could reduce the adverse effects of size difference and was suitable for the determination of soluble solid content of gongpear with different size grades.
2023, 47(4): 534-540.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.014
Abstract:
In order to solve the problems of poor portability and inability to measure transient temperature of traditional multi-spectral radiation thermometers, a portable high-speed multi-spectral radiation thermometer was developed by adopting the spectroscopic method of splitting fiber+band-pass filter, and a high-speed photoelectric response circuit was designed. The results show that, the complexity of the system can be effectively reduced and the portability can be improved by using optical fiber and band-pass filter to replace the traditional prism and package it with other hardware of the thermometer. After assembly, the overall mass of the instrument is not more than 4 kg, and the volume is not more than 30 cm×25 cm×25 cm. The photoelectric conversion circuit with high bandwidth was designed, and the high-speed analog digital conversion chip, field-programmable gate array chip and CYUSB3014 chip were used for digital signal acquisition and transmission. The communication rate with the computer is up to 100 MHz, so that the thermometer can measure the temperature with microsecond change. The actual temperature measurement results of muffle furnace temperature after calibration show that the overall relative error of the thermometer is less than ±2.5% and the temperature measurement accuracy is high when the reference temperature is stable. This result is helpful to improve the portability of the thermometer and realize the high-precision temperature measurement of transient temperature field.
In order to solve the problems of poor portability and inability to measure transient temperature of traditional multi-spectral radiation thermometers, a portable high-speed multi-spectral radiation thermometer was developed by adopting the spectroscopic method of splitting fiber+band-pass filter, and a high-speed photoelectric response circuit was designed. The results show that, the complexity of the system can be effectively reduced and the portability can be improved by using optical fiber and band-pass filter to replace the traditional prism and package it with other hardware of the thermometer. After assembly, the overall mass of the instrument is not more than 4 kg, and the volume is not more than 30 cm×25 cm×25 cm. The photoelectric conversion circuit with high bandwidth was designed, and the high-speed analog digital conversion chip, field-programmable gate array chip and CYUSB3014 chip were used for digital signal acquisition and transmission. The communication rate with the computer is up to 100 MHz, so that the thermometer can measure the temperature with microsecond change. The actual temperature measurement results of muffle furnace temperature after calibration show that the overall relative error of the thermometer is less than ±2.5% and the temperature measurement accuracy is high when the reference temperature is stable. This result is helpful to improve the portability of the thermometer and realize the high-precision temperature measurement of transient temperature field.
2023, 47(4): 541-546.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.015
Abstract:
To study the interaction pattern of nanosecond pulse laser with aluminium debris, a dynamic response model of nanosecond pulse laser irradiation on aluminum debris was established, the dynamic characteristics of plasma expansion plumes under different action times and incident laser powers was investigated by COMSOL software, and the evolution rules of plasma expansion plumes generated by nanosecond pulse laser irradiating the debris were obtained with different laser parameters. The results show that the expansion velocity of plasma plumes increases with the increase of action times based on the same pulse laser power. At the same time, the maximum velocity of plasma expansion plumes increases with the increase of laser powers based on the same pulse laser time. According to the given conditions of this article, the maximum velocity of expansion plumes reached the maximum around 25 μs, and the maximum velocity at 700 kW is 1.87×104 m/s owing to the plasma shielding effect. At the moment, the diffusion radius of the plasma expansion plumes increases by 17 mm. The study provides a theoretical reference for the engineering application of nanosecond pulse laser irradiation of aluminium space debris de-orbiting removal.
To study the interaction pattern of nanosecond pulse laser with aluminium debris, a dynamic response model of nanosecond pulse laser irradiation on aluminum debris was established, the dynamic characteristics of plasma expansion plumes under different action times and incident laser powers was investigated by COMSOL software, and the evolution rules of plasma expansion plumes generated by nanosecond pulse laser irradiating the debris were obtained with different laser parameters. The results show that the expansion velocity of plasma plumes increases with the increase of action times based on the same pulse laser power. At the same time, the maximum velocity of plasma expansion plumes increases with the increase of laser powers based on the same pulse laser time. According to the given conditions of this article, the maximum velocity of expansion plumes reached the maximum around 25 μs, and the maximum velocity at 700 kW is 1.87×104 m/s owing to the plasma shielding effect. At the moment, the diffusion radius of the plasma expansion plumes increases by 17 mm. The study provides a theoretical reference for the engineering application of nanosecond pulse laser irradiation of aluminium space debris de-orbiting removal.
2023, 47(4): 547-552.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.016
Abstract:
In order to realize automatic detection of contraband in X-ray images and to work out troubles of detecting mutual shaded, close and small-target prohibited items, an meliorative detection method on the strength of you only look once(YOLOX) algorithm was presented. Firstly, the spatial attention constructed with large kernel attention was introduced in the lower layer of YOLOX backbone network to extract the long-distance dependence information and texture message of the feature map in the lower layer. Then, the convolution block attention module was inserted in the middle and high layer of YOLOX backbone network to heighten the region of interest information and restrain unnecessary information. The proposed means was experimented on an overt security inspection X-ray dataset, meanwhile, in order to strengthen the robustness of the model, Mosaic data augmentation was used in the first 70 training epoch. The results show that, comparing with the basic model, the improved model put on a small amount of parameters and calculations. Mean average precision increases by 2.45% to 87.88%, and average inference velocity is 58.5 frames/s. This study can provide a salutary reference for automatically immediate detection of prohibited items in X-ray images.
In order to realize automatic detection of contraband in X-ray images and to work out troubles of detecting mutual shaded, close and small-target prohibited items, an meliorative detection method on the strength of you only look once(YOLOX) algorithm was presented. Firstly, the spatial attention constructed with large kernel attention was introduced in the lower layer of YOLOX backbone network to extract the long-distance dependence information and texture message of the feature map in the lower layer. Then, the convolution block attention module was inserted in the middle and high layer of YOLOX backbone network to heighten the region of interest information and restrain unnecessary information. The proposed means was experimented on an overt security inspection X-ray dataset, meanwhile, in order to strengthen the robustness of the model, Mosaic data augmentation was used in the first 70 training epoch. The results show that, comparing with the basic model, the improved model put on a small amount of parameters and calculations. Mean average precision increases by 2.45% to 87.88%, and average inference velocity is 58.5 frames/s. This study can provide a salutary reference for automatically immediate detection of prohibited items in X-ray images.
2023, 47(4): 553-557.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.017
Abstract:
To explore whether petroleum ether (PE) emits fluorescence or not and whether its residual in olive oil (OL) can be detected by fluorescence method or not, the fluorescence characteristics of PE and its composition with OL at different proportions were experimentally investigated by adopting fluorometry. The results show that PE exists fluorescence which consists of UV spectral region 320 nm~380 nm and purple-green spectral region 380 nm~520 nm. At the excitation region 240 nm~300 nm, the intensity of the two spectra increases with increase of excitation wavelength, but the first spectral region is stronger. At the excitation wavelength of 305 nm, the first spectral region begins to weaken. When the excitation wavelength is larger than 320 nm, the UV spectral region weakens and disappears quickly, while the second region continues to increase with increase of excitation wavelength. When the excitation wavelength increases to 360 nm, the second spectrum becomes the strongest. When the excitation wavelength is larger than 360 nm, the fluorescence weakens. Addition of small amount of PE into OL can enhance the OL characteristic peaks and even lead to appearance of the red-shifted characteristic peak 405 nm of PE, which can be utilized to detect PE residual in OL. The volume fraction limit of detection of PE in OL can reach 0.059, 0.048, and 0.043 for the excitation wavelength 320 nm, 340 nm, and 360 nm, respectively. This work expands the research of PE to fluorescence and fluorescence detection of PE residual in OL.
To explore whether petroleum ether (PE) emits fluorescence or not and whether its residual in olive oil (OL) can be detected by fluorescence method or not, the fluorescence characteristics of PE and its composition with OL at different proportions were experimentally investigated by adopting fluorometry. The results show that PE exists fluorescence which consists of UV spectral region 320 nm~380 nm and purple-green spectral region 380 nm~520 nm. At the excitation region 240 nm~300 nm, the intensity of the two spectra increases with increase of excitation wavelength, but the first spectral region is stronger. At the excitation wavelength of 305 nm, the first spectral region begins to weaken. When the excitation wavelength is larger than 320 nm, the UV spectral region weakens and disappears quickly, while the second region continues to increase with increase of excitation wavelength. When the excitation wavelength increases to 360 nm, the second spectrum becomes the strongest. When the excitation wavelength is larger than 360 nm, the fluorescence weakens. Addition of small amount of PE into OL can enhance the OL characteristic peaks and even lead to appearance of the red-shifted characteristic peak 405 nm of PE, which can be utilized to detect PE residual in OL. The volume fraction limit of detection of PE in OL can reach 0.059, 0.048, and 0.043 for the excitation wavelength 320 nm, 340 nm, and 360 nm, respectively. This work expands the research of PE to fluorescence and fluorescence detection of PE residual in OL.
2023, 47(4): 558-564.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.018
Abstract:
For the sake of solving the problem of surface wear and failure of the hot work die, based on ANSYS APDL software, a Gaussian heat source was applied to the hot work die by numerical simulation, and the H13 alloy powder was clad by the life and death element method. The process parameters were optimized and selected through the temperature field and stress field. The optimized process parameters were tested and verified, and the performance of the coating was tested. The results show that the optimal simulation parameters within the selected parameter range are the laser power of 1200 W and the scanning speed of 12 mm/s. The simulation results are close to the morphology and temperature distribution of the actual coating. The heat-affected zone in the numerical simulation and the combination of the results are highly consistent with the experimentally prepared results; the measured depth of the cladding layer is 0.13 mm, which corresponds to the simulated depth of 0 mm~0.2 mm, which further illustrates the reliability of the simulation results; the hardness and wear resistance of the cladding layer have been greatly improved, which are 3 times and 28 times more than that of the matrix, respectively. The results of this study provide a reference for strengthening and repairing hot work molds.
For the sake of solving the problem of surface wear and failure of the hot work die, based on ANSYS APDL software, a Gaussian heat source was applied to the hot work die by numerical simulation, and the H13 alloy powder was clad by the life and death element method. The process parameters were optimized and selected through the temperature field and stress field. The optimized process parameters were tested and verified, and the performance of the coating was tested. The results show that the optimal simulation parameters within the selected parameter range are the laser power of 1200 W and the scanning speed of 12 mm/s. The simulation results are close to the morphology and temperature distribution of the actual coating. The heat-affected zone in the numerical simulation and the combination of the results are highly consistent with the experimentally prepared results; the measured depth of the cladding layer is 0.13 mm, which corresponds to the simulated depth of 0 mm~0.2 mm, which further illustrates the reliability of the simulation results; the hardness and wear resistance of the cladding layer have been greatly improved, which are 3 times and 28 times more than that of the matrix, respectively. The results of this study provide a reference for strengthening and repairing hot work molds.
2023, 47(4): 565-571.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.019
Abstract:
In order to study the characteristics of the structure of wind shear, the low-level wind shear at Urumqi Airport on 2021-11-26 was analyzed by using the FC-Ⅲ wind light detection and ranging(LiDAR) data, the reanalysis data of National Centers for Environmental Prediction, and conventional meteorological observation data. The evolution of wind shear was calculated. The results show that, the wind shear process occurred under the condition of a specific terrain wind. The small scale of cold air caused the significant changes in wind direction and speed, the bottom of the southeast jet and the northwest wind belt form a vertical shear area inclined upward which led to the cold-front type of low-level wind shear. The wind field around airports had been changed 1 h before the occurrence of wind shear. And the wind shear area was detected 10 min earlier than the report from aircraft which based on the plan position indicator model, the area where wind shear occurred was significant variations in the southeast wind speed, and also followed the movement of cold air to the west. During the movement of cold air, the southeast wind layer became thinner and retreated to the west. Near the glide path 07#. There was not only a sharp reduction of the frontal crosswind, but also a significant change in wind direction. The cold air was wedged from 25# to 07# during 08:30~10:25. The small-scale of cold air activity at low altitude was captured, and a backward of evolution process and structure was figured out, which showed that the pathway entering the airport from northeast, and issued the wind shear warning. The study is helpful to improve the meteorological service support capacity.
In order to study the characteristics of the structure of wind shear, the low-level wind shear at Urumqi Airport on 2021-11-26 was analyzed by using the FC-Ⅲ wind light detection and ranging(LiDAR) data, the reanalysis data of National Centers for Environmental Prediction, and conventional meteorological observation data. The evolution of wind shear was calculated. The results show that, the wind shear process occurred under the condition of a specific terrain wind. The small scale of cold air caused the significant changes in wind direction and speed, the bottom of the southeast jet and the northwest wind belt form a vertical shear area inclined upward which led to the cold-front type of low-level wind shear. The wind field around airports had been changed 1 h before the occurrence of wind shear. And the wind shear area was detected 10 min earlier than the report from aircraft which based on the plan position indicator model, the area where wind shear occurred was significant variations in the southeast wind speed, and also followed the movement of cold air to the west. During the movement of cold air, the southeast wind layer became thinner and retreated to the west. Near the glide path 07#. There was not only a sharp reduction of the frontal crosswind, but also a significant change in wind direction. The cold air was wedged from 25# to 07# during 08:30~10:25. The small-scale of cold air activity at low altitude was captured, and a backward of evolution process and structure was figured out, which showed that the pathway entering the airport from northeast, and issued the wind shear warning. The study is helpful to improve the meteorological service support capacity.
2023, 47(4): 572-578.
doi: 10.7510/jgjs.issn.1001-3806.2023.04.020
Abstract:
Abnormal changes of the nasolabial sulcus characteristics are important symptoms of stroke, usually as the basis for the stroke facial diagnosis by traditional Chinese medicine with naked-eye observation. In order to quantify the characteristics of nasolabial sulcus and to solve the problem that it is difficult to find fine feature changes and difficult to communicate information in traditional Chinese medicine facial diagnosis, the polarization parametric indirect macroscopic imaging(PIMI) method was adopted by using the Stokes S1 parametric image. The nasolabial sulcus characteristics of healthy people, stroke patients, and prognostic people were obtained. The results show that the nasolabial sulcus S1 data of healthy people has good symmetry, while it is obviously asymmetrical for the stroke patients, and the difference between the left and right peaks is more than 20. It becomes more symmetrical when the stroke patient gets better. This method is expected to be applied to the digital diagnosis of stroke diseases and the evaluation of the treatment process, promoting the development of digital Chinese medicine.
Abnormal changes of the nasolabial sulcus characteristics are important symptoms of stroke, usually as the basis for the stroke facial diagnosis by traditional Chinese medicine with naked-eye observation. In order to quantify the characteristics of nasolabial sulcus and to solve the problem that it is difficult to find fine feature changes and difficult to communicate information in traditional Chinese medicine facial diagnosis, the polarization parametric indirect macroscopic imaging(PIMI) method was adopted by using the Stokes S1 parametric image. The nasolabial sulcus characteristics of healthy people, stroke patients, and prognostic people were obtained. The results show that the nasolabial sulcus S1 data of healthy people has good symmetry, while it is obviously asymmetrical for the stroke patients, and the difference between the left and right peaks is more than 20. It becomes more symmetrical when the stroke patient gets better. This method is expected to be applied to the digital diagnosis of stroke diseases and the evaluation of the treatment process, promoting the development of digital Chinese medicine.
