发明人： 王秩伟，吴黄宇，刘锦锦，李永恺，胡金国，姚裕贵

申请人： 北京理工大学，晶工新材料(扬中)有限公司

申请号： 202311039448.X

申请日期： 2023.08.17

摘要： 本发明涉及Kagome材料RMn₆Sn₆单晶及其制备方法，属于单晶材料技术领域。R为Zr或Hf，其中，ZrMn₆Sn₆的单晶结构为：P6/mmm空间群，a=5.410Å，b=5.410Å，c=8.982Å，α=9 ...

作者： An Li;Xinyu Zhang;Xiaodong Liu;Yage He;Yuheng Shan;Haohan Sun;Wen Yi,and Ruibin Liu^;; （Key Lab of Precision Spectroscopy and Optoelectronic Technology, School of Physics, Beijing Institute of Technology, Beijing 100081, China Corresponding author: liusir@bit.edu.cn Find other works by these authors A Li X Zhang X Liu Y He Y Shan H Sun W Yi R Liu Open Access Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text An Li, Xinyu Zhang, Xiaodong Liu, Yage He, Yuheng Shan, Haohan Sun, Wen Yi, and Ruibin Liu, Real time and high-precision online determination of main components in iron ore using spectral refinement algorithm based LIBS, Opt. Express 31 , 38728-38743 (2023) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article Check for updates More Like This In situ elemental analysis and failures detection during additive manufacturing process utilizing... Vasily N. Lednev, et al. Opt. Express 27 ;⁴ 4612-4628 (2019) Highly sensitive detection of sodium in aqueous solutions using laser-induced breakdown... Ryuzo Nakanishi, et al. Opt. Express 29 ;⁴ 5205-5212 (2021) Data augmentation using continuous conditional generative adversarial networks for regression and... Yuhao Zhu, et al. Opt. Express 31 ;²³ 37722-37739 (2023) Related Topics Table of Contents Category Spectroscopy and Spectrometers Optics & Photonics Topics ? The topics in this list come from the Optics and Photonics Topics applied to this article. Absorption spectroscopy Aluminum oxide Laser induced breakdown Optical components Optical systems Systems design About this Article History Original Manuscript: September 11, 2023 Revised Manuscript: October 11, 2023 Manuscript Accepted: October 12, 2023 Published: October 31, 2023 PDF Article Back to Article Article Outline Abstract Introduction Online LIBS analyzer framework Sample and methods Online quantitative determination Conclusion References and links Figures ( 9 ) Suppl. Mat. (;²) Data Availability Tables ( 4 ) Equations ( 4 ) References ( 35 ) Cited By ( 0 ) Back to Top Abstract The real-time online quantitative analysis instrument is highly desirable for many industrial fields. Herein,;¹new laser-induced breakdown spectroscopy (LIBS) setup with optimized optical route and high accuracy algorithm is designed and applied in;¹real industrial site. The components of total iron (TFe), silica (SiO2), aluminum oxide (Al2O3), and phosphorus (P) are quantitatively determined by the online LIBS system. The key optical part is;¹Maksutov-Cassegrain telescope, in which, two aspherical mirrors are specially designed and fabricated to reflect the broadband emission from ultraviolet 240 nm to infrared 890 nm with reflectivity over 90%, and pass the excited laser line of 1064 nm. The system could automatically adjust the focal length in the range of 780 mm to 940 mm. Based on the online LIBS system, the spectral pretreatment algorithm is also optimized including baseline removal and spectral normalization. The overlapped window slide (OWS) algorithm avoids the deformation of emission peaks in spectral baseline removal, in addition, two normalization steps by total back area and total spectral intensity within the sub-channel are applied to improve the spectral data stabilization. The calibration and validation are performed by utilizing the emissions that are insensitive to the detection distance. Compared with the traditional method, the prediction result shows that the root of mean square error of prediction (RMSEP) decreased from 5.091% to 1.2328%, and the mean absolute error (MAE) reduced from 4.801% to 0.9126% for TFe. Eventually, the online measurement shows good agreement with the official standard results. The high-precision online determination system based on LIBS will upgrade low frequency sampling of traditional detection to high-frequency real online determination in many industrial fields. © 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement 1. Introduction Customs and ports always need to quantitatively and rapidly analyze elemental content in raw iron ore, the total iron and other matrix matter affects the production process and the settlement price in steelworks. Generally,;¹docked cargo ship carries several hundred thousand tons of ore, and the conveyer belt connects the ship and steel mill directly for highly efficient unloading. The traditional quantitative analysis in conventional laboratories mainly involves sampling every 100 tons of ore from;¹belt conveyor, using traditional methods for offline post-processing and analysis, including atomic absorption spectroscopy, X-ray fluorescence, or chemical titration, which always take several hours or days ¹. Consequently, the low sampling representativeness and the significant feedback delay hinder the management of steelworks to refine production processes. Laser-induced breakdown spectroscopy (LIBS) is;¹suitable online analysis method with fast and real-time quantitative capabilities. The high sampling frequency provides;¹significant statistical analysis result of mineral on the belt conveyer. Many researchers have successfully conducted industrial at-line analysis of various minerals based on LIBS ;²– 4 . However, most at-line analysis processes mainly rely on auxiliary sample processing equipment located near the main belt conveyor 5 , sampling the block from the material flow and reprocessing the raw material to appropriate state for analysis. For example, in the coal industry, coal blocks are usually taken from conveyors and then crushed and granulated to;¹diameter less than 0.2 µm particles, and then press the coal powder into pellets under dozens of tons of pressure 6 – 8 . For each pellet sample, ablation hundreds of times in;¹certain sequence by the laser pulses. Finally, the spectral preprocessing and statistical algorithms of quantitative analysis are combined to measure the elemental content in coal. Compared to traditional analysis based on manual operation in the laboratory, the online determination save time and labor, but it is still;¹huge challenge to directly analyze the material flow on the moving belt. As to the iron ore in the port, unloading and transporting is synchronized, reprocess raw ore by sampling from the belt conveyer is not suit for the end-to-end transportation. Therefore, it is necessary to directly embed the LIBS analyzer online and analyze the high-speed moving raw ore on the belt. However, the complexity of industrial sites and the uncontrollability of the raw ore state have become new challenges for online LIBS solutions, such as the mixing of fly ash on material stream and iron ore with different sizes, which greatly affects the availability and stability of spectral data, thereby to reduce the precision and accuracy. Due to the irregular shape of the raw ore and changes in the height of material stream on the conveyor, most online LIBS applications need automatic focusing components. Coaxial optics schemes, such as Maksutov-Cassegrain telescope architecture with reflective optics or other remote analysis configurations rely on Galilean telescope configuration with refractive optics, are considered as the effective solution. Laserna and his workmates designed;¹remote sensor based on an autofocusing system to detect soil samples twenty years ago, the expander consisted of two lenses, and meanwhile, the focusing length was adjusted by those two lenses 9 . Patrick developed an online LIBS scanning system by the refraction-optics-based autofocusing system, they measured the aluminum alloy on;¹moving belt with;¹speed of;³m/s 10 , 11 , but the chromatism was not considered in such system. Reinhard et al. carried out an online LIBS system and installed it above;¹moving coal conveyer 4 , the system measured the ash content with;¹relative small range of 1.5% ∼2.8%. Redoglio et al. combined the Galilean system and two off-axial mirrors to measure the raw coal block 12 , the optical system has;¹large depth of field with 20 cm by which the laser fluence irradiate on the different rock materials maintain stable. A coaxial optical configuration was developed for mineral quantitative analysis in Josette’s work 5 , they use the resulting data of EDS-SEM to guide the results obtained by LIBS, and the RMSE of prediction result presented below 10% for the main minerals. In addition, there are some researchers developed integrated commercial LIBS units for qualitative or quantitative analysis of raw minerals online. M. Gaft et al. developed;¹machine named MAYA based on LIBS technology to evaluate coal bulk on;¹moving belt conveyer 13 , the online instrument revealed consistent results compared with prompt gamma neutron activation analyses (PGGAA) for ash analysis online, the absolute error of 2% ∼ 4% for ash measurement, but the correlation between online system and local laboratory is worse 14 . The online analyzer MAYA is also used to monitor the content of Cu, CaO, SiO2, and S for Cu-bearing minerals, and to determine the Fe and CaO content in Fe-based ore 15 . The most famous one is the LIBS analysis device made by NASA(SuperCam) that is carried on the Mars rover 16 , it is;¹special space online device, and has many valuable technologies to learn from. SuperCam chose the Cassegrain telescope as the autofocusing system to detect remote soil material 17 , the RMSEP of main composition SiO₂ on Mars’ soil was 6.1% 18 , 19 . Until now, the reported online LIBS configurations still have lower accuracy. Especially, the optical components with both high damage threshold and broad spectral reflectivity still need to be further enhanced. In brief,;¹universal optical system with related high-accuracy algorithm is still missing for the real on-line detection. Herein, considering the complexity and physicochemical state of the raw materials, we developed an online LIBS system for quantitatively determining the main components in iron ore on;¹fast-moving belt conveyor with the speed of 4∼4.5 m/s. On the basis of optimizing the spectral continuum fitting algorithm, two-step spectral normalization was carried out to reduce the fluctuation of spectral signals. In addition, based on the study of the variable importance of projection (VIP) in modeling, we found that certain emissions are not sensitive to detection length during autofocus. Finally, based on these insensitive emissions, the online machine was calibrated and the model was applied online. The predicted results of the online LIBS analyzer are compared with the official report, indicating that the chemical abundances of TFe, SiO2, Al₂O₃, and P are in good agreement with the routine laboratory. 2. Online LIBS analyzer framework 2.1. Optical system design For high-efficiency and cost reduction, raw ore is transported directly from the cargo ship to the steel mill by the belt conveyer in the port, the running velocity of the belt is usually set at 4∼4.5 m/s. It is significantly different that the size of raw ore from the crab bucket dumped into the belt conveyer, which is the basis of the design for autofocusing range of the optical system. The online LIBS analyzer OL-FeCam is designed to quantitatively analyze iron ore online based on the autofocusing optical system. As listed in the Table. ¹ , the parameters demonstrate the autofocusing range, that is the working distance of the optical system, should be able to automatically adjust from 780 mm to 940 mm. For optical components used in online LIBS systems, refractive optical lenses are often prone to involve chromatism and aberration, especially for optical systems with long focal lengths. Therefore, reflective optics (without achromatic aberration) are necessary for signal acquisition. To overcome these issues, we chose reflective optics based on the Maksutov-Cassegrain architecture as the initial design input for the optical theme. Due to the fact that the size of the focused laser spot needs to maintain stability with changes in focal length, two aspheric mirrors M₁ and M₂ were designed for the minimum axial aberration under different focusing lengths, as shown in Figs. ¹ (a) and (b). Fig. 1. (a) The design scheme layout of online LIBS analyzer, L₁&L₂: beam expander, L₃: collection lens, D: dichroic with reflection wavelength 240 nm∼ 950 nm and transmission wavelength 1000 nm ∼ 1200 nm. (b) Enlarge view of two aspheric mirrors, M₁: primary mirror, hyperboloid, M₂: secondary mirror, paraboloid with;¹hole in the central. (c) The α-prototype machine in the laboratory. (d) The online LIBS analyzer installed above the belt conveyer. (e) The optical and mechanical schematic view inside the analyzer. (f) The electronic control system built into the bones of the machine. Download Full Size | PDF Note that there is;¹large amount of emission in the ultraviolet region of the spectrum, and quantitative analysis based on the spectrum requires collecting plasma emission signals within the range of ultraviolet to visible light. Therefore, the optical components related to spectral signal collection, including two main mirrors M₁, M₂, and dichroism D, are HR coating relative to the ultraviolet region. In addition, the dielectric protective film layer must also be attached to the HR coating to meet the high damage threshold requirements, as listed in the Table ¹ . In other words, optical components correlated to reflective surfaces are typically customized to suit industrial sites. Table 1. The optical design requirement of online ore LIBS analyzer View Table | View all tables in this article 2.2 Prototype α-machine As shown in Fig. ¹ (c), the prototype machine named α-Online Fe-Cam (hereinafter referred to as α-machine) is established in the laboratory. The beam with;¹diameter of 6 mm is output from;¹Q-switched Nd: YAG laser (Ziyu, Penny 300A, 1064 nm, China), and the laser pulse duration is 6 ns. The output laser energy is 300 mJ, and the laser fluence is approximately 1.06 J/cm² with the beam diameter is 6 mm. The energy irradiates on the sample surface is 195 mJ. The laser beam is expanded to reduce the fluence to protect the coating layer of the mirror M₁, the beam expander consisted of two quartz lenses L₁(focus length f = -19 mm) and L₂ (f = 50.8 mm) with;¹magnification of ×2. The radiation emission of plasma is coupled to;¹five-fiber cable (5 × 200 µm), and then transmit the light to the spectrometer (Avantes, AVS-DESKTOP-USB2 StarLine, wavelength range 179.68 nm to 893.83 nm with the resolution less than 0.1 nm of each channel). The integration time of the spectrometer is set to 30 us. The delay time between the spectrometer and the laser pulse is 0.5 µs. The autofocusing is adjusted by moving the mirror M₁ along the optical axis, the working distance, i.e., the detection length from mirror M₂ to the sample surface is 860 ± {\pm} 80 mm corresponding to the separation of 95.8 ± {\pm} 1.8 mm between the mirror M₁ and M₂. 2.3 Control logic design of automatic focusing system In the laboratory, the prototype α-machine is constructed to validate the quantitative algorithm, the schematic diagram is demonstrated in Fig. ;² . The autofocusing system is controlled by two microcontroller units (MCUs) C₁ (Arduino UNO, ATMEGA 328P-AU, Italy) and C₂ (Arduino Mega, ATMEGA 2560, Italy). The motors Z₂ and Z₃ control the sample stage T moving within the x-y plane, which is directed perpendicular to the paper surface, and the position of T in the z-direction is controlled by;¹slide below the sample stage. The motor Z₁ holds the mirror M₁ and drives the mirror along the optical axis, the focal length changes as Z₁ moved. The distance sensor S (Omron, ZX-LD300, Japan) is installed behind the mirror M₁ to measure the distance between stage T and M₂. Combining signal filter (SF) and the 16-bit high-speed analog-to-digital converter (ADC) read and preprocess the distance sensor data. The control panel is shown in Fig. ¹ (f), which includes two MCUs, SF, ADC, and three motor drivers. (the detail of control sequence is available in Supplement¹, part IV) Fig. 2. The control principle layout of online LIBS system, Z₁∼Z₃: motor controlled movin）

出处： Optics Express 2023 Vol.31 No.23 P38728-38743

关键词： Absorption spectroscopy;Aluminum oxide;Laser induced breakdown;Optical components;Optical systems;Systems design

摘要： The real-time online quantitative analysis instrument is highly desirable for many industrial fields. Herein, a new laser-induced breakdown spectrosco ...

作者： Qi, Zhiying¹; Mi, Linjie¹; Qian, Haoran²; Zheng, Weiguo²; Guo, Yao¹; Chai, Yang³ （¹School of Physics, Beijing Institute of Technology, Beijing, Haidian; 100081, China;²School of Data Science, Fudan University, No. 220 Handan Road, Shanghai; 200433, China;³Department of Applied Physics, The Hong Kong Polytechnic University, 999077, Hong Kong）

出处： Advanced Functional Materials 2023