Contents
2024
Volume: 44 Issue 3
25 Article(s)
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Effects of the Temporal and Spatial Profile of Laser Beam on the Microstructure of 316L Stainless Steel in Laser Based Energy Deposition
Zheng xiaoqiang, Wu Jiazhu, Cao yang, Zhang Dabin, and Sun Jie
This paper investigates the temporal and spatial profiles of laser beams as control parameters for the preparation of single track multi layer 316L stainless steel specimens using laser based directed energy deposition. The effects of parameters on the microhardness and microstructure characteristics of the specimens wThis paper investigates the temporal and spatial profiles of laser beams as control parameters for the preparation of single track multi layer 316L stainless steel specimens using laser based directed energy deposition. The effects of parameters on the microhardness and microstructure characteristics of the specimens were analyzed. The orthogonal experiments results show that key evaluation indicators, including grain equivalent diameter, aspect ratio of columnar grains, and quantitative ratio of columnar to equiaxed grains, initially decrease sharply and then exhibit slight increases with rising frequency and duty cycle of pulsed wave lasers. Comparing with the continuous beam, the grain equivalent diameter, aspect of columnar grains, quantify ratio of columnar/equiaxed grain under the medium frequency (40/60Hz) and medium duty cycle (0.6/0.8) are decreased by 19.4%, 3.4%,13.3%, respectively. As for the spatial profile, compared with the Gaussian profile beam, the grain equivalent diameter under the super Gaussian beam decreased by 0.14, while the aspect of columnar grains, quantify ratio of columnar/equiaxed grain increase by 0.06 and 0.45, respectively. The effect degree of each factor on equivalent diameter, aspect of columnar grains, quantify ratio of columnar/equiaxed grain and microhardness are as follows: duty cycle > frequency >spatial profile index, frequency > duty cycle >spatial profile index, frequency > spatial profile index > duty cycle, spatial profile index > frequency > duty cycle..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 1 (2024)
Optimization of Process Parameters for Laser Additive Manufacturing of TiAl Alloy Based on the Response Surface Method
Cui Baolei, Liu Weijun, and Bian Hongyou
In order to reduce crack occurrence during the laser additive manufacturing of TiAl alloy, a predictive model was developed to analyze the relationships between process parameters (laser power, scanning speed, and powder feed rate) and crack formation. The study utilized the number of cracks as the response index to inIn order to reduce crack occurrence during the laser additive manufacturing of TiAl alloy, a predictive model was developed to analyze the relationships between process parameters (laser power, scanning speed, and powder feed rate) and crack formation. The study utilized the number of cracks as the response index to investigate the influence of process parameters and their interactions. Response surface and genetic algorithm techniques were used to optimize the process parameters, and the microstructure near the crack and the root cause of crack formation were examined. Results underscored the significant impact of laser power on crack occurrence, with fewer cracks observed at higher laser powers. Comparative analysis of optimization algorithms favored the genetic algorithm, achieving crack free samples with optimal parameters: laser power of 1 754 W, scanning speed of 9mm/s, and powder feed rate of 7g/min. Furthermore, the volatilization of Al near cracks facilitated the formation of the brittle α2 phase, while localized enrichment of α2 phase rendered cracks more susceptible to stress induced failure during the laser additive process..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 13 (2024)
Influence of Inclination of Laser Cladding Nozzle on Cladding Layer Morphology of High Inclination Substrate
Sun yewang, Shi Tuo, Wei wei, Bian xiaoqian, Zhang Rongwei, Zhang Qi, and Wei chao
This study investigates the impact of varying inclination angles of the cladding nozzle on processing outcomes under different substrate inclinations using laser cladding technology with internal powder feeding. The orthogonal experiment of laser cladding was carried out by controlling the inclination angle of the subsThis study investigates the impact of varying inclination angles of the cladding nozzle on processing outcomes under different substrate inclinations using laser cladding technology with internal powder feeding. The orthogonal experiment of laser cladding was carried out by controlling the inclination angle of the substrate between 30° and 150° and rotating the inclination angle of the nozzle counterclockwise between 0°and 15°. The results show that the laser energy distribution, the influence of gravity component and the collimation protective gas pressure have different influence weights after adjusting the nozzle position under different substrate tilt states. The peak point offset of the cladding layer initially increases and then decreases with nozzle tilt angle when the substrate inclination is non-90°. Conversely, at a substrate inclination of 90°, the peak point offset decreases initially and then increases with increasing nozzle tilt angle..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 22 (2024)
Microstructure and Properties of Laser Cladding FeCrNiB Alloy Bath Cross Section
Duan Shaolan, Lei weining, Shan Xinghai, Chen Ning, Li zhixian, and Jian wenxuan
The FeCrNiB alloy coating was applied to the surface of U71Mn rail steel. The macroscopic morphology, microscopic morphology, and phase composition of the coating were characterized by metallographic microscope, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) for two sections along the cladThe FeCrNiB alloy coating was applied to the surface of U71Mn rail steel. The macroscopic morphology, microscopic morphology, and phase composition of the coating were characterized by metallographic microscope, scanning electron microscope (SEM), and energy dispersive spectrometer (EDS) for two sections along the cladding direction and vertical cladding direction. Vickers hardness testing and friction and wear testing were conducted to measure the hardness and wear resistance of the coating. The examination revealed the absence of defects such as air holes and cracks at the bottom of the transverse and longitudinal sections of the cladding layer, indicating good metallurgical bonding. In the YOZ cross section cladding layer perpendicular to the cladding direction, coarse dendrites and some equiaxed crystals were observed, while in the XOZ cross section cladding layer along the cladding direction, slender dendrites and more equiaxed crystals were present.. Through software analysis and the circular cutting point method, the grain size of YOZ section is about 11 grades, and that of XOZ section is about 12 grades. The hardness of cladding layer in XOZ section is slightly higher than that in YOZ section. The weight loss, wear rate and friction coefficient of XOZ section are slightly smaller than those of YOZ section, and the running in period of XOZ section is shorter..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 31 (2024)
Effect of Laser Power on Microstructure and Tribological Property of Laser Cladded Ni 60%WC Coatings
He Chuang
Ni-60%WC coatings were prepared on 45 steel via the laser cladding process, employing various laser power settings. The microstructure of obtained coatings was analyzed using a super depth of field microscope. The effect of laser power on the tribological performance of Ni 60%WC coating was investigated using a wear teNi-60%WC coatings were prepared on 45 steel via the laser cladding process, employing various laser power settings. The microstructure of obtained coatings was analyzed using a super depth of field microscope. The effect of laser power on the tribological performance of Ni 60%WC coating was investigated using a wear tester, and the wear mechanism was discussed by the wear model. The results show that the average coefficients of friction of Ni 60% WC coating at the laser power of 1 400, 1 700, 2 000 and 2 300 W are 0.291, 0.375, 0.338, and 0.261, respectively, and the corresponding wear rates are 26.48, 21.44, 30.24, and 27.36 μm3/(N·mm), respectively. The wear rate of Ni 60%WC coating at the laser power of 1 700 W decrease by 19%, 29%, and 22% compared with those at the laser power of 1 400, 2 000 and 2 300 W, respectively, which indicates that the appropriate laser power may improve its wear resistance. Furthermore, laser power exhibited negligible influence on the wear mechanism of Ni 60%WC coatings, with abrasive wear and adhesive wear identified as the primary modes of degradation..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 40 (2024)
Research on the Modeling Method for Predicting the Geometric Shape of Automotive Parts Using IDBO KELM Based Laser Cladding
You zhiping, Ma Hong, Liang Qun, and Wang Guanhua
As an environmentally friendly and reliable technology, laser cladding is widely used for surface hardening and damage repair of automotive parts. Combining the trial and error method and Taguchi method, we designed laser melting experiments to investigate the forming process parameters of laser melting 316L alloy powdAs an environmentally friendly and reliable technology, laser cladding is widely used for surface hardening and damage repair of automotive parts. Combining the trial and error method and Taguchi method, we designed laser melting experiments to investigate the forming process parameters of laser melting 316L alloy powder on the surface of 45# steel. Laser power, scanning speed, and powder feeding speed served as variable parameters, while the dung beetle optimization algorithm with multi strategy fusion was employed to optimize hyper parameters of the kernel limit learning machine. Regression prediction models for evaluation indices of the laser cladding process (width to height ratio and dilution rate) were established, achieving coefficients of determination of 0.973 5 and 0.975 9, with average absolute percentage errors of 0.007 7% and 0.061 2%, respectively. Using Taguchi's method for analyzing the causal analysis, the effects of laser cladding process parameters on the dilution rate were ranked as follows: laser power (P)> powder feeding speed (F)> scanning speed (V), and the effects of aspect ratio were ranked as follows: powder feeding speed (F)> scanning speed (V)> laser power (P). The experimental results show the accuracy of the proposed method, and the ideal regression prediction model of the aspect ratio and dilution rate of cladding layer can be obtained, which can provide a theoretical basis for the quality control of cladding layer..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 50 (2024)
A Workpiece Segmentation Method Based on the Laser Point Cloud Convexity and Euclidean Clustering
Long Jian, Lu Anjiang, Zhao Qi, Peng xishun, yang Jiao, and Liu HongTao
In The segmenTaTion of elecTronic componenTs under The laser poinT cloud，The complex siTuaTion of disTribuTion be- Tween The workpieces makes iTimpossible for The TradiTional poinTcloud segmenTaTion algoriThm To achieve correcTsegmenTaTion and counTing. In This paper，a poinT cloud segmenTaTion meThod using LCCP and eucIn The segmenTaTion of elecTronic componenTs under The laser poinT cloud，The complex siTuaTion of disTribuTion be- Tween The workpieces makes iTimpossible for The TradiTional poinTcloud segmenTaTion algoriThm To achieve correcTsegmenTaTion and counTing. In This paper，a poinT cloud segmenTaTion meThod using LCCP and euclidean clusTering is proposed. The LCCP algoriThm based on surface convexiTy is used To perform coarse segmenTaTion of poinT clouds，separaTe workpieces sTacked on Top of each oTher wiTh small collision area , and exTracTThe poinTcloud clusTers of The remaining colliding workpieces；Secondly，The boundary deTecTion meThod based on normal esTimaTion is used To remove The edge poinTpoinTs of The exTracTed poinTcloud clusTers，so ThaTThe poinT clouds of The workpieces in conTacT wiTh each oTher are separaTed in space，and Then The euclidean clusTering algoriThm is used for fine segmenTaTion；Finally，The resulTof The coarse and fine segmenTaTion is merged To compleTe The segmenTaTion. The resulTs show ThaTunder complex siTuaTions，The proposed meThod can accuraTely spliTThe TargeTarTifacT, and The accuracy of The segmenTaTion is improved by 35. 9%，66. 7% and 80% compared wiTh LCCP, regional growTh and Eu- clidean clusTering algoriThms，respecTively，and The average Time consumpTion per 10 TargeTs is abouT290 ms，which has good accuracy and pracTicaliTy..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 63 (2024)
Study on Cleaning Process of Stainless Steel by Laser with Different Pulse Width
Wang Aming, Feng Aixin, Gu xinhua, Pan xiaoming, and Yu Jinhai
laser technique;laser cleaning;laser ablation;316L stainless steellaser technique;laser cleaning;laser ablation;316L stainless steel.
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 71 (2024)
Virtual Assembly of Large Bridge Steel Components Based on Super Voxel
Liu DeIer, Chen xingyu, Si xuanxuan, and Xia Rongcheng
The virtual pre assembly process of bridge steel components faces challenges such as time consumption, large footprint, and high costs. This paper proposes an automatic virtual pre assembly technology for bridge steel components, employing supervoxel segmentation and a region growing algorithm to achieve precise segmenThe virtual pre assembly process of bridge steel components faces challenges such as time consumption, large footprint, and high costs. This paper proposes an automatic virtual pre assembly technology for bridge steel components, employing supervoxel segmentation and a region growing algorithm to achieve precise segmentation of component point cloud feature surfaces. The method accommodates the unique geometry of carling and crossbeam members. Using singular value decomposition algorithm, random consistency fitting algorithm and spatial geometry principle to automatically extract the feature points needed for Mosaic, the traditional point cloud Mosaic control points in the manual selection of large subjectivity, accuracy is difficult to control and other problems effectively solved. Moreover, the paper introduces data threshold and design value auxiliary line methods to ensure accurate assembly, even in scenarios with missing component scanning point cloud data. Engineering application results demonstrate an average error of 0.62 mm, a maximum error of only 1.32 mm, and a maximum angle error of 0.139°, indicating reasonable accuracy control and strong applicability. Based on the research results, a group of algorithm plug ins are developed on the Cloud Compare platform to further realize the automation and standardization of the stitching process. The research results can provide theoretical and algorithmic support for virtual preassembly of bridge steel and similar engineering projects, and reflect better production and application value..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 87 (2024)
Lidar SLAM Algorithm Based on Lidar Iris Loop Closure Detection
Hao FengTong, Wu Yelan, Guan wenyang, Zhang Junjing, and wang Jiaqi
To address challenges such as low positioning accuracy, poor robustness, and weak loop closure detection in traditional LiDAR odometry for outdoor wide range scenes, this paper proposes a LiDAR SLAM algorithm based on LiDAR iris loop closure detection. Firstly, the laser point cloud motion distortion is corrected by coTo address challenges such as low positioning accuracy, poor robustness, and weak loop closure detection in traditional LiDAR odometry for outdoor wide range scenes, this paper proposes a LiDAR SLAM algorithm based on LiDAR iris loop closure detection. Firstly, the laser point cloud motion distortion is corrected by combining the IMU pre processing data. Secondly, a lidar iris loop closure detection is established, where aerial views of the laser point cloud are encoded by height information and then converted to lidar iris images. Similarity scores among these iris images are calculated to identify optimal loop closure key frames, effectively enhancing loop closure detection accuracy. Finally, the factor graph backend optimization approach is used to co optimize the loop closure factor, lidar odometry factor, and IMU preintegration factor for obtaining globally optimal solution. The test results on the KITTI dataset show that compared with the ALOAM and LeGO LOAM algorithms, the proposed algorithm improves the positional accuracy by 50% and 37% on average. Additionally, it accurately detects loop closures, significantly enhancing localization accuracy and mapping effectiveness..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 97 (2024)
A Study on Adaptive Vehicle Height Detection Algorithm Based on Single Line LiDAR
Huang Xiling, Hu Jin, Wang Li, Yuan Shanshan, Zhang Lei, Zong Xu, Luo Haiyan, Xu Bin, and Zhou Feng
To address the pressing issue of frequent collisions between over height vehicles and bridges, which pose significant road safety hazards, this study introduces an innovative solution. We have developed an adaptive vehicle height detection algorithm based on single line LiDAR technology. Utilizing two dimensional laserTo address the pressing issue of frequent collisions between over height vehicles and bridges, which pose significant road safety hazards, this study introduces an innovative solution. We have developed an adaptive vehicle height detection algorithm based on single line LiDAR technology. Utilizing two dimensional laser scanning technology, the algorithm automatically identifies the ground and accurately measures vehicle height. Experiments demonstrate that the algorithm effectively limits vehicle height measurement errors to within ±2 cm, achieving a 100% detection rate with 0% false positives during continuous monitoring. Upon detecting over height vehicles, the system immediately signals for video tracking, evidence preservation, or activation of audio visual alarms. These results confirm the algorithm's high precision and reliability in the vehicle height restriction field, along with its stability, adaptability, low cost, and ease of maintenance, thus highlighting its considerable value in this field..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 106 (2024)
A Calibration Method for Rotary Table Reference Axis of Line Scan Gear Measuring Machine
Yang HongTao, Liu shiping, Liu yueqi, zhang shuangshuang, and Li Li
To enhance the measurement accuracy of gear size and shape errors, a model of the influence of the eccentricity and tilt errors of the reference axis on the measurement of gears and the evaluated accuracy of gears is established for the research object of a line scan gear measuring machine, which has the difficult of cTo enhance the measurement accuracy of gear size and shape errors, a model of the influence of the eccentricity and tilt errors of the reference axis on the measurement of gears and the evaluated accuracy of gears is established for the research object of a line scan gear measuring machine, which has the difficult of calibrating the reference axis of rotary table. Based on this, an improved method for calibrating reference axis based on monocular vision is proposed. Fixing the checkerboard grid parallel to the turntable, using the camera to collect the feature point data, using the least squares method to fit the spatial plane and center of the circle of the feature point, and finally completing the reference axis calibration.The experimental results show that compared with the results of the calibration before the improved method, the tilted angle between the calibrated axis and the standard reference axis of the calibration after the improved method is reduced by 65.227 1% and the value of eccentricity is reduced by 47.875 2%.The error of the improved calibration results is significantly reduced and the calibration results are more accurate. Compared with other calibration methods, the calibration method is simple to operate..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 115 (2024)
Precision Measurement of Gears Based on Laser Bias
Xu Guicai, Mei Ning, Song Aiping, and Jiang Kaijia
During laser gear measurement, the laser beam typically intersects the gear′s center, measuring the spatial distance from the laser displacement sensor to the involute tooth surface. However, the substantial angle between the laser beam and the normal vector of the measured tooth face compromises measurement accuracy aDuring laser gear measurement, the laser beam typically intersects the gear′s center, measuring the spatial distance from the laser displacement sensor to the involute tooth surface. However, the substantial angle between the laser beam and the normal vector of the measured tooth face compromises measurement accuracy and data stability. To address this issue, this paper proposes a laser offset measurement method for gears. By offsetting the laser beam from the gear axis, the angle between the laser beam and the tooth surface normal vector is reduced, thereby enhancing measurement accuracy and stability. The paper calculates the optimal offset range and analyzes gear pitch deviation and helix deviation by examining gear tooth shape. Theoretical projection and experimental verification confirm the method′s advantages of high accuracy and minimal data fluctuation, rendering it suitable for highprecision gear measurement..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 124 (2024)
Application of Wavelet Denoising in NonCooperative Target Laser Methane Telemetry
Jiang Jing, Cheng Yue, Yin Songfeng, Liu Dong, and Zhou Zhen
This study addresses challenges in noncooperative target laser methane telemetry, including complex noise, low signaltonoise ratio, and detection limit issues. We explore the application of wavelet denoising as a solution to these challenges. By analyzing actual measurement signals, we identify the coif5 waveletbasThis study addresses challenges in noncooperative target laser methane telemetry, including complex noise, low signaltonoise ratio, and detection limit issues. We explore the application of wavelet denoising as a solution to these challenges. By analyzing actual measurement signals, we identify the coif5 waveletbased 7layer decomposition fixed soft threshold method as the optimal denoising approach. The performance parameters such as calibration, measurement error and detection limit of the telemetry system by wavelet denoising are studied. The results show that the measurement error range of the system after wavelet denoising is reduced from -2.89 %~7.20 % to -2.32 %~6.51 %, the detection limit was increased from 425.664 7×10-6 m（3σ） to 104.839 0×10-6 m（3σ）, and the detection limit was increased by 3 times. The selected wavelet denoising method significantly reduces complex noise in the noncooperative target laser methane telemetry system, potentially enhancing its detection performance..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 132 (2024)
Simulation and Design of Coaxial Zero Blind Zone Meter Scattering Lidar System
Li Dongxu, Sun Gaofei, Yi Wensuo, Jiang Yuchen, and Zhao Rui′an
To address limitations of traditional meter scattering lidar in detecting large blind areas at close range, we present a coaxial meter scattering lidar aerosol detection system. Firstly, numerical simulation of the signal to noise ratio of the system echo signal is carried out based on the standard atmospheric model anTo address limitations of traditional meter scattering lidar in detecting large blind areas at close range, we present a coaxial meter scattering lidar aerosol detection system. Firstly, numerical simulation of the signal to noise ratio of the system echo signal is carried out based on the standard atmospheric model and lidar system parameters. This study mainly discussed the influence of laser pulse energy, radar receiving aperture and pulse accumulation number on the echo signal to noise ratio, of which the increase in the radar receiving aperture is the most obvious improvement. Secondly, a balanced detector is designed to convert the scattered return light into a photoelectric; Finally, based on the system structure, a movable meter scattering lidar experimental platform was built. The atmospheric aerosol was preliminarily detected, and the experimental results showed that the increase in the emitted laser pulse energy had little influence on the explorative distance. This system can reach a 10 km explore distance effectively. The balanced detection method is 2.7 times which is higher the direct detection method. The coaxial design of the system makes the close detection blind zone almost zero, and the spatial resolution can reach 120 m..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 142 (2024)
ResearchontheApplicabilityofUAVLiDARinPowerLineSurvey
Tan Jinshi, Zu Weiguo, Liu Bo, Zheng Binyan, and Gao Shihu
Linesurveysarecrucialforpowerdesigners,yettraditionalsurveymethods,includingengineeringsurveying,photogrammetry,andmannedairbornelidar,oftenfallshortofcurrentrequirements.UAVLiDARisflexible,lowcost,convenienttooperate,andthelaserpointcloudhaspenetrability,whichcanobtainlaserpointcloudandimagedataatthesametime,whichcanwLinesurveysarecrucialforpowerdesigners,yettraditionalsurveymethods,includingengineeringsurveying,photogrammetry,andmannedairbornelidar,oftenfallshortofcurrentrequirements.UAVLiDARisflexible,lowcost,convenienttooperate,andthelaserpointcloudhaspenetrability,whichcanobtainlaserpointcloudandimagedataatthesametime,whichcanwellsolvetheshortcomingsinlinesurvey.ThispaperstudiestheapplicabilityofUAVLiDARinlinesurveying.First,thebasicprinciplesandtechnicalroutesaredescribed.Then,keytechnologiessuchasUAVgroundflight,overheadwirecrossingmeasurement,andterrainconsideringclothsimulationfilteringarecarriedout.Research,andfinallythroughexperimentstocarryoutadaptiveresearchandanalysis.TheresultsshowthattheUAVlidarcanobtainlaserandimagedatainthestripareawithlowcostandhighefficiency,thepointclouddensitypenetratingtothegroundis1~3points/m2,thewireelevationmeasurementaccuracyis±0.057m,andthepointcloudplaneisTheaccuracyis±0.12m,andtheelevationaccuracyis0.07~0.23m,allofwhichcanmeettherequirementsoflinesurveyaccuracy.Comparedtotraditionalmethods,UAVLiDARrepresentsatechnologicalleapforward,offeringsignificantapplicationandpromotionpotential..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 150 (2024)
Research on Environment Temperature Adaptive Control Technology for LDs in Laser Energy Supply Systems
Song Dongdong, Hu Guiping, Yan Min, Zhao Senlin, Deng Yingkai, and Li Shaodong
Semiconductor lasers (LDs) are commonly used as power sources in active electronic DC measurement systems due to their advantages of electrical isolation and electromagnetic immunity. Due to the fact that the active electronic DC measurement system often operates outdoors, the working temperature of the LDs will be affSemiconductor lasers (LDs) are commonly used as power sources in active electronic DC measurement systems due to their advantages of electrical isolation and electromagnetic immunity. Due to the fact that the active electronic DC measurement system often operates outdoors, the working temperature of the LDs will be affected by the environment, leading to the measurement errors of the system. Therefore, it is necessary to perform environmental temperature adaptive control on the LDs to ensure that it operates within the normal temperature range and the system obtains stable measurement. In this paper, a study of environment temperature adaptive control technology for LDs in active electronic DC measurement system is carried out. Based on the principle of temperature control for LDs, the relationship between environmental temperature, tube core temperature, and thermoelectric cooler (TEC) driving current was simulated and studied through multiple physical fields. Then an environment temperature adaptive PID control algorithm, which combines steady state regulation based on environment temperature with transient regulation based on core temperature, is proposed to improve the stability of the core temperature. Experimental research is also conducted using Keil MDK software and an STM32 development board. The results indicate that the proposed control algorithm can decrease the transient power fluctuation of LD from 0.72% to 0.38%，confirming the viability of the proposed solution.
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 162 (2024)
Research on Remote Infrared Monitoring System for Digital Operation Safety of Distribution Network Based on Laser Nonlinear Imaging Technology
Gao Junwei, An Zhiguo, Yu Sifan, Li Yingfeng, Li Songjie, and Hong Haisheng
In order to accurately identify the digital operators of distribution network and improve the effect of remote infrared monitoring of digital operation safety of distribution network, a remote infrared monitoring system of digital operation safety of distribution network based on laser nonlinear imaging technology is sIn order to accurately identify the digital operators of distribution network and improve the effect of remote infrared monitoring of digital operation safety of distribution network, a remote infrared monitoring system of digital operation safety of distribution network based on laser nonlinear imaging technology is studied. The system entails the design of a comprehensive digital image acquisition process covering the SF6 layer and the infrared application layer. Furthermore, it encompasses the hardware configuration of a remote infrared monitoring terminal tailored for the digital operation safety of distribution networks, aligned with the structural and imaging principles of SF6 laser nonlinear cameras. The software component orchestrates the remote infrared monitoring process, incorporating a convolutional neural network algorithm to construct a multi scale pyramid for operator feature extraction. Pixel features are then enhanced through fast local Laplace filter transformation. Intrusion behavior detection within hazardous areas is achieved via softmax function, facilitating safe remote infrared monitoring of distribution network digital operations. The experimental results show that the image enhancement processing ability and operator recognition effect of the system are ideal, and can timely and effectively warn the intrusion behavior of operators in the dangerous area. The warning time is always less than 0.06 s, and the comprehensive performance of network transmission is excellent. The maximum amount of data packet loss is 5 000, which improves the effect of safe remote infrared monitoring of digital operation in distribution network..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 171 (2024)
Research Progress in Application Technology of Distributed Feedback Fiber Lasers
Hong Yumeng, Song Zhiqiang, Yang Yuanyuan, Zhang Xucheng, and Ni Jiasheng
In recent years, with the rapid development of coherent detection technology, single frequency laser has received great attention. The distributed feedback fiber laser has the characteristics of both intrinsic single longitudinal mode and highly sensitive vibration string structure. It has important application value iIn recent years, with the rapid development of coherent detection technology, single frequency laser has received great attention. The distributed feedback fiber laser has the characteristics of both intrinsic single longitudinal mode and highly sensitive vibration string structure. It has important application value in the field of low noise single frequency light source and fiber laser sensing technology. Based on the application requirements, this paper summarizes the related research achievements of distributed feedback fiber laser in narrow line width light source and fiber laser sensor technology. According to the different requirements of frequency response characteristics of distributed feedback fiber laser in application, the research progress of related technologies is introduced. Finally, the applicability of different distributed feedback fiber laser frequency response processing methods is compared. The future application prospect of distributed feedback fiber laser is also prospected..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 179 (2024)
Application Progress of Spectral Analysis Combined with Chemometrics in Forensic Identification、
Jie Zhaowei, Liu Zhuo, Wang Jifen, Liu Fubang, and Wu Shihao
In the past decade, modern spectral instrument analysis technology and chemometrics had been applied to the classification and prediction of physical evidence, so as to realize the accurate identification and analysis of the characteristic information of physical evidence. This paper discussed in detail the chemometricIn the past decade, modern spectral instrument analysis technology and chemometrics had been applied to the classification and prediction of physical evidence, so as to realize the accurate identification and analysis of the characteristic information of physical evidence. This paper discussed in detail the chemometrics methods used in the spectral analysis of forensic material evidence identification, compared their advantages and disadvantages and applicability, and summarized the application progress of spectral analysis combined with chemometrics in four important forensic material evidence identification fields: Food and drug inspection, trace material evidence inspection, biological material evidence inspection and document inspection, in order to promote the further research and application of Chemometrics in forensic science..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 192 (2024)
Street Lamp Extraction Method Based on Unmanned Aerial Vehicle Point Cloud
Yang Wei, Cheng Liang, Zhu Daming, Chen Song, Duan Zhixin, Du Siyu, Yu Jun, Zhuang Qizhi, and Dongye Shengkun
This paper addresses the automatic extraction of street lamps from 3D point clouds using unmanned aerial vehicle (UAV) data, proposing a sample matching layered extraction method. Firstly, the original point cloud is divided into three layers: lamp head layer, lamp pole layer and ground layer by cloth simulation filterThis paper addresses the automatic extraction of street lamps from 3D point clouds using unmanned aerial vehicle (UAV) data, proposing a sample matching layered extraction method. Firstly, the original point cloud is divided into three layers: lamp head layer, lamp pole layer and ground layer by cloth simulation filtering(CSF) algorithm, and hierarchical clustering is carried out. Then, the point cloud of lamp pole is extracted by sample matching algorithm. Finally, based on the relative position constraint between the lamp head point cloud and the center of the lamp pole, the lamp head point cloud is extracted, thus completing the extraction of the whole street lamp. Our experimental results show that in different road environments, the correctness, completeness and F1 indices of street lamps extracted by the proposed method are not less than 90%, which can achieve efficient and complete extraction of the street lamp..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 223 (2024)
Experimental Study on Influencing Factors of Tree Barrier Removal Efficiency of Transmission Line by Laser
Liu Zhipeng, Lei Dong, Huang Meng, Chen Haowei, Fang Chunhua, Hu Tao, Lü Junjie, and Li Fang
Utilizing high energy lasers for transmission line tree barrier removal has shown promising outcomes. This paper investigates the influencing factors on laser clearing efficiency for four tree species, focusing on laser power, tree species, water content, and wind speed. The results show that the ablation efficiency isUtilizing high energy lasers for transmission line tree barrier removal has shown promising outcomes. This paper investigates the influencing factors on laser clearing efficiency for four tree species, focusing on laser power, tree species, water content, and wind speed. The results show that the ablation efficiency is negatively correlated with tree density and positively correlated with water content, wind speed, and laser power. The higher the density of trees burned through, the lower the efficiency and the longer it takes to clear the obstacles. When the trees with 50.4% moisture content are burned by laser, it is not easy to produce a carbonization layer that hinders the penetration of laser energy. The removal time is shorter than the trees with 14.2% moisture content. With the same power laser, the barrier removal efficiency of the line laser is much higher than that of the point laser. When the diameter of trees is 10.50 mm~35.50 mm, the time required to use a point laser is 2.48~6.12 times that of a line laser. With the increase in diameter, the point laser takes more time to remove, indicating that the larger the diameter of the tree barrier, the higher the efficiency of using the line laser. This research result provides an essential basis for applying and developing laser tree barrier removal devices..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 223 (2024)
Research Advances in Laser Treatment of White Spot Lesions
Wang Guoqing, Liu Yuyan, Chen Jinquan, Tian Lei, and Sun Xiumei
White Spot Lesions (WSLs) are a prevalent complication in orthodontic practice. In recent years, the utilization of laser technology in WSL treatment has garnered attention, yielding promising therapeutic outcomes. Laser technology holds significant value in safeguarding dental health and preserving aesthetic outcomes White Spot Lesions (WSLs) are a prevalent complication in orthodontic practice. In recent years, the utilization of laser technology in WSL treatment has garnered attention, yielding promising therapeutic outcomes. Laser technology holds significant value in safeguarding dental health and preserving aesthetic outcomes post treatment. This article provides a review of recent advancements in laser treatment for WSLs and summarizes the underlying mechanisms of action involved in this approach..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 230 (2024)
Efficacy of Photodynamic Therapy Combined with Initial Periodontal Therapy for Peri Implantitis
Liu Zhihuan, Zhu Baomin, and Li Hong
Objective To systematically review the efficacy of photodynamic therapy combined with initial periodontal therapy in the treatment of periodontitis. Methods PubMed, Embase, Cochrane Library, and Web of Science were searched from database inception to June 30, 2022. The randomized controlled studies of photodynamic therObjective To systematically review the efficacy of photodynamic therapy combined with initial periodontal therapy in the treatment of periodontitis. Methods PubMed, Embase, Cochrane Library, and Web of Science were searched from database inception to June 30, 2022. The randomized controlled studies of photodynamic therapy combined with the treatment of peri implantitis were collected and evaluated by two participants. After the researchers independently screened the literature according to the inclusion and exclusion criteria, extracted the data and evaluated the quality, the RevMan5.3 software was used to conduct a Meta analysis of the studies that met the inclusion criteria. Results A total of 636 articles were screened, resulting in 8 included studies. Meta analysis indicated that PDT combined with basic periodontal therapy improved clinical efficacy. After 3 months, the intervention group exhibited superior outcomes in bleeding, probing depth, and clinical attachment level compared to controls (P<0.05). After 6 months, bleeding, probing depth, and bone loss favored the intervention group (P<0.05). At 12 months, bone loss was significantly reduced in the intervention group (P<0.05). Conclusions PDT combined with periodontal basic treatment for implant periodontitis significantly improves bleeding on probing, probing depth, bone loss, and clinical attachment level..
APPLIED LASER
- Publication Date: Aug. 16, 2024
- Vol. 44, Issue 3, 236 (2024)
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