“LIBS关键技术与应用”专辑前言

激光诱导击穿光谱(LIBS)是一种基于原子发射光谱的物质分析技术,具有样品预处理简单、系统简洁、原位在线探测、多元素同步分析等优点。随着激光器、光谱仪、人工智能等相关技术的发展,LIBS被广泛应用于流程工业、地理环境、生物医学、深空探测等诸多领域,被誉为化学分析技术的“未来巨星”。

基于LIBS的GdFe合金材料快速检测技术研究

为了明晰LIBS(激光诱导击穿光谱)技术检测稀土合金材料的光谱特点,进一步开发基于LIBS的快速检测方法,推动LIBS技术在稀土领域的应用。利用激光诱导击穿光谱仪对GdFe合金材料激发光谱,结合信号强度及背景噪音,研究确定了最佳设置参数。分别考察激光器和光谱仪的参数设置对光谱的影响,根据激发光谱中相关谱线的变化趋势,探讨GdFe合金材料的LIBS检测方法。实验发现,GdFe合金样品与激光孔(Laser aperture)的距离(Z值)、激光能量和积分时间是影响LIBS光谱信号强度和背景噪音的关键参数。因金属和合金样品表面常覆盖氧化层,考察了脉冲激光的预剥蚀次数对光谱稳定性的影响,研究得出,在双脉冲均为164 mJ激光能量的激发下,预剥蚀1次可保证光谱效果。同时研究了两个激光器同时激发和延迟激发对GdFe合金光谱成因的影响,发现单脉冲激发与双脉冲同时激发所得光谱的信号强度并非两束脉冲单独激发的累加信号。通过光谱分析,确定了Z值0.8 mm、两个激光器的脉冲能量164 mJ、积分时间12μs、脉冲延时时间0μs,GdFe合金材料的光谱效果最佳,可为GdFe合金材料的LIBS检测方法建立提供参考,拓展LIBS技术在稀土领域的应用,为稀土合金产品的快速检测技术发展提供基础研究数据。

激光诱导击穿光谱(LIBS)技术在低碳钢铁冶金行业的应用

激光诱导击穿光谱技术(Laser induced breakdown spectroscopy,简称LIBS)是一种基于激光等离子体的发射光谱技术,具有样品制备简单,分析迅速,多元素同时分析,现场在线和远程分析等独特优势,已在钢铁冶金领域取得了越来越广泛的应用与发展。综述了近年来LIBS技术在钢铁冶金领域的应用研究进展,从冶金生产的全流程进行介绍,包括矿石、熔融钢水/铁水、钢铁产品及炉渣和废气分析。同时,还总结了LIBS技术在钢铁冶金领域应用的优点和缺点,并对该技术的应用前景及未来发展方向进行展望。

高精度煤质成分快速定量分析LIBS系统研究

煤质成分的快速、高精度定量分析是工厂对能源高效利用的重要环节。本文通过利用搭建的激光诱导击穿技术煤质快速分析仪,对所采集煤样工业特性固定碳(FixC),灰分(Ash),干燥无灰基的挥发分(Vdaf),热值(Q)进行了定量测量,并对测得的数据与实验室人工测量数据进行对比分析,检验得出该方法在煤质分析方面准确快速。通过对设备稳定性和动态精密度的测试,结果表明了快速煤质分析仪具有较高的稳定性,满足国标规定值。在预测灰分值分布跨度为5%~60%的煤样时,通过增加样品量,增加模型中对大灰分煤样的预测权重,实现预测均方根误差RMSEP<1%的预测精度,挥发分和全硫的RMSEP<1%,热值的RMSEP<0.18 MJ/kg。预测结果均达到工业分析要求,可以满足工业现场的应用需求,具有应用于煤质在线检测方面的广阔前景。

圆柱形空间约束对LIBS检测煤粉颗粒流的优化研究

为了提高激光诱导击穿光谱技术(LIBS)检测煤粉颗粒流时光谱信号的质量和检测结果的可靠性,根据颗粒流的检测特点,设计了一种圆柱形空间约束,并分析了其对LIBS直接检测煤粉颗粒流的实验系统的优化效果。先后对比分析了添加约束前后煤中一些重要元素的特征谱线的绝对强度、信噪比(SNR)和脉冲到脉冲间的相对标准偏差(RSD)等重要信息。结果表明:圆柱形空间约束能够有效地提升LIBS检测煤粉颗粒流的光谱强度和信号的稳定光谱信号的重复性,达到提高检测结果的可靠性的目的。

激光诱导击穿光谱(LIBS)法微损快速检测党参中Pb

中药材重金属元素快速检测对污染监控及人们健康具有重要意义。激光诱导击穿光谱技术(Laser induced breakdown spectroscopy,LIBS)属于一种快速检测方法,研磨压片等预处理方法相对样品消解已有所简化,但破坏了样品的物理性质,且不能满足中药材大宗品种、大批量检测需求。若进一步简化样品预处理,将更加凸显LIBS快速检测的优势。采用Pb溶液浸泡法获得不同Pb含量的党参切片样品,依次获取Pb LIBS光谱强度,通过排序初步判断Pb含量高低,随机从各含量梯度样品中抽取样品,将其分为三份:38个A样用于ICP-MS检测,建立定标曲线,从而获取B样和C样中Pb真实含量,10个B样作为Pb浓度已知的参考定标样品,用于待测党参样品中Pb微损检测,19个C样用于验证B样微损检测准确性。建立的微损定标曲线线性相关系数R^(2)为0.7764,可用于切片党参LIBS快速检测,对待测党参切片样品检测平均相对误差为3.74%,与电感耦合等离子体质谱(ICP-MS)法对比,相关系数R^(2)为0.7957,验证了LIBS技术微损检测的可行性。制备的党参参考定标样品可多次重复用于待测样定标和仪器标定等。实验对待测党参样品仅进行切片处理,避免了研磨、压片等预处理,更加充分地体现LIBS快速检测的优势,为LIBS技术应用于中药材重金属元素快检等领域提供了一种新方法。

激光诱导击穿光谱(LIBS)结合字典学习对气溶胶光谱数据筛选方法的研究

气溶胶是大气中的重要组分,对气候、生态环境等均有重要的影响。激光诱导击穿光谱(LIBS)在用于气溶胶检测时,由于气溶胶的离散分布,导致采集到大量无效光谱。通过制备7种不同浓度的NaCl气溶胶样品,选取NaCl溶液(10%)的5000条光谱数据进行分类,其中70%作为训练集,30%作为测试集,建立一种结合字典学习对有效光谱数据进行筛选的方法——K-SVD-SVM。当字典基向量数设置为3时,模型分类性能最优,准确率(Accuracy)、精确率(Precision)、召回率(Recall)、精确率和召回率的调和平均(F1)分别达到96%、95%、95%、0.95。此外,采用K-SVD-SVM方法对7种不同浓度的气溶胶样品进行筛选后,输入结合遗传算法的极限学习机(GA-ELM)模型开展定量分析,同时将未筛选的原始光谱数据输入定量模型进行对比。未筛选的原始数据测试集RMSE和R^(2)分别是0.0303和0.8726,筛选光谱后,分别提升至0.0187和0.9809。结果表明,K-SVD-SVM方法有着较好的分类性能,且采用此方法筛选出的有效数据可以为气溶胶中元素定量分析提供数据支撑。

基于LIBS光谱实现燃煤企业碳排放量高精度快速预测

准确预测煤炭的碳排放数据是实现中国“双碳”目标的重要基础。在煤炭入炉前完成碳排放量数据和煤质指标的精确、快速预测,将转变目前“先排放,后检测”的碳排放数据计算方式,对落实“双碳”战略意义重大。以煤炭碳含量和煤质指标的精准预评估为研究目标,通过自行搭建激光诱导击穿光谱(Laser Induced Breakdown Spectroscopy,LIBS)系统和LIBS光谱统计分析,利用主成分分析-偏最小二乘(PCA-PLS)结合小样本算法对训练集进行回归训练,建立了一种煤炭的碳排放预测模型,并通过在新疆A电厂和山东B电厂中的实际应用,证明了LIBS系统在煤质指标分析中的可靠性。结果表明:所提出的预测方法与传统方法相比绝对误差最大为0.0256 t,表现出较好的碳排放预测能力。所提方法可以用于燃煤企业碳排放量的精准预测,为实现煤炭碳排放和煤质指标的预评估提供了一种较为高效的技术解决路径。

Detection of Al, Mg, Ca, and Zn in copper slag by LIBS combined with calibration curve and PLSR methods

The precise measurement of Al, Mg, Ca, and Zn composition in copper slag is crucial for effective process control of copper pyrometallurgy. In this study, a remote laser-induced breakdown spectroscopy(LIBS) system was utilized for the spectral analysis of copper slag samples at a distance of 2.5 m. The composition of copper slag was then analyzed using both the calibration curve(CC) method and the partial least squares regression(PLSR) analysis method based on the characteristic spectral intensity ratio. The performance of the two analysis methods was gauged through the determination coefficient(R^(2)), average relative error(ARE), root mean square error of calibration(RMSEC), and root mean square error of prediction(RMSEP). The results demonstrate that the PLSR method significantly improved both R^(2) for the calibration and test sets while reducing ARE, RMSEC, and RMSEP by 50% compared to the CC method. The results suggest that the combination of LIBS and PLSR is a viable approach for effectively detecting the elemental concentration in copper slag and holds potential for online detection of the elemental composition of high-temperature molten copper slag.

Laser-induced plasma formation in water with up to 400 mJ double-pulse LIBS

Double-pulse LIBS is a promising technique for deep-sea applications.LIBS measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can occur.Optical emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic pressure.It has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.

基于LIBS技术的渣选尾矿中铜元素的在线检测研究

白银有色集团股份有限公司选矿公司为及时获知渣选尾矿中准确的铜元素含量,针对化验室取样分析方法存在取样代表性差、分析时间长等问题,采用基于LIBS技术的在线分析仪对铜尾矿中铜元素含量进行了在线检测应用研究。通过分析20个铜尾矿样品中铜元素含量化验室离线检测值与在线检测值,结果表明,平均绝对偏差为0.014%,平均相对偏差为4.79%,线性相关性R^(2)可达0.959以上,满足铜尾矿铜回收率的判断需要,可为铜熔炼渣浮选加工提供指导。

Ultrafast carrier dynamics in GeSn thin film based on time-resolved terahertz spectroscopy

We measure the time-resolved terahertz spectroscopy of GeSn thin film and studied the ultrafast dynamics of its photo-generated carriers.The experimental results show that there are photo-generated carriers in GeSn under femtosecond laser excitation at 2500 nm,and its pump-induced photoconductivity can be explained by the Drude–Smith model.The carrier recombination process is mainly dominated by defect-assisted Auger processes and defect capture.The firstand second-order recombination rates are obtained by the rate equation fitting,which are(2.6±1.1)×10^(-2)ps^(-1)and(6.6±1.8)×10^(-19)cm^(3)·ps^(-1),respectively.Meanwhile,we also obtain the diffusion length of photo-generated carriers in GeSn,which is about 0.4μm,and it changes with the pump delay time.These results are important for the GeSn-based infrared optoelectronic devices,and demonstrate that Ge Sn materials can be applied to high-speed optoelectronic detectors and other applications.

基于LIBS迭代的工业燃煤锅炉精细化配煤掺烧优化决策技术

配煤掺烧中涉及的燃料种类和成分较多,工业燃煤锅炉的运行效率、氮氧化物产量等受到影响,故提出基于LIBS迭代的工业燃煤锅炉精细化配煤掺烧优化决策技术。分析与阐明配煤掺烧特性,基于LIBS迭代技术,获取配煤元素LIBS光谱数据,利用S-G滤波器去除LIBS光谱噪声数据,应用随机森林方法提取LIBS光谱数据特征,定量检测配煤元素,以氮氧化物产量最小,工业燃煤锅炉效率最大为目标,构造配煤掺烧优化决策函数,制定目标函数求解程序,执行程序即可获得工业燃煤锅炉精细化配煤掺烧优化决策方案。实验数据显示:在不同实验组别背景下,应用提出技术获得的氮氧化物总产量最小值为200 mg·m^(3),工业燃煤锅炉效率最大值为96%,充分证实了提出技术应用性能更优质。

Time-resolved characteristics of a nanosecond pulsed multi-hollow needle plate packed bed dielectric barrier discharge

In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.

A research on the effect of plasma spectrum collection device on LIBS spectral intensity

Only a small amount of spectral information is collected because the collection solid angle of the optical fiber probe and lens is very limited when collecting spectral information.To overcome this limitation,this study presents a novel method for acquiring plasma spectral information from various spatial directions.A parabolic-shaped plasma spectral collection device(PSCD)is employed to effectively collect more spectral information into the spectrometer,thereby enhancing the overall spectral intensity.The research objects in this study were soil samples containing different concentrations of heavy metals Pb,Cr,and Cd.The results indicate that the PSCD significantly enhances the spectral signal,with an enhancement rate of up to 45%.Moreover,the signal-to-noise ratio also increases by as much as 36%.Simultaneously,when compared to the absence of a device,it is found that there is no significant variation in plasma temperature when the PSCD is utilized.This observation eliminates the impact of the spatial effect caused by the PSCD on the spectral intensity.Consequently,a concentrationspectral intensity relationship curve is established under the PSCD.The results revealed that the linear fitting R^(2)for Pb,Cr,and Cd increased by 0.011,0.001,and 0.054,respectively.Additionally,the limit of detection(LOD)decreased by 0.361 ppm,0.901 ppm,and 0.602 ppm,respectively.These findings indicate that the spectral enhancement rate elevates with the increase in heavy metal concentration.Hence,the PSCD can effectively enhance the spectral intensity and reduce the detection limit of heavy metals in soil.

基于LIBS的燃煤电厂煤质在线智能检测研究

常规的煤质在线检测方法以灼烧称重的形式为主,经过采样、化验等多个环节,影响了煤质分析的准确性。因此,本文设计了基于LIBS的燃煤电厂煤质在线智能检测方法。提取燃煤电厂煤质光谱特征,分析光谱线上的化学、物理状态信息。基于LIBS构建燃煤电厂煤质在线智能检测模型,映射光谱特征与煤质指标之间的关系。使用定标检测电厂煤质单变量元素,建立LIBS光谱数据定量关系,准确检测单元素的含量。本文采用对比试验,试验结果表明该方法的检测准确性更高,能够应用于实际。

激光诱导击穿光谱技术(LIBS)定量分析缅甸翡翠中的镁与钙

激光诱导击穿光谱对于宝玉石的定量分析一直是研究热点和难点,为了拓展激光诱导击穿光谱在宝石学研究与检测领域的应用,采用激光诱导击穿光谱(LIBS)对22个缅甸翡翠样品进行镁、钙含量的测量和分析,选取Ca(315.954 nm)、Mg(285.210 nm)和作为定标分析谱线,以Si(288.170 nm)光谱线作为内标谱线。以15个样品分别绘制出了基于谱线强度和基于谱线积分强度的MgO与CaO内定标曲线,基于谱线强度内定标法分析建立的MgO与CaO拟合曲线的相关系数R^(2)分别为0.904和0.949,以检验集中7个样品检验定标曲线,MgO与CaO的LIBS测量值与参考值的相对偏差分别为9.4%~42.2%、4.1%~55.2%,与样品参考值的偏差分别低于0.47%、0.73%;而基于谱线积分强度内定标法分析建立的MgO与CaO元素拟合曲线的相关系数R^(2)分别为0.947和0.973,以检验集中7个样品检验定标曲线,MgO与CaO的LIBS测量值与参考值的相对偏差分别为3.7%~34.9%、3.8%~37.3%,与样品参考值的偏差分别低于0.56%、0.49%。实验结果表明,基于谱线的积分强度的内定标法提高LIBS检测翡翠中MgO与CaO的精确度。研究表明,LIBS对翡翠样品的定量分析具有可靠的重复性和准确性,在宝石学研究领域具有重要的应用潜力。

Establishment of Double-antigen Sandwich Time-resolved Fluorescence Immunoassay for Detection of Pest des Petits Ruminants Virus

[Objectives]This study was conducted to explore rapid and large-scale screening and detection of peste des petits ruminants(PPR),so as to provide important technical means for prevention,control and purification of PPR.[Methods]Soluble N protein and NH fusion protein were successfully obtained in an Escherichia coli expression system by optimizing E.coli codon and expression conditions.Furthermore,based on purified soluble N protein and NH fusion protein,a double-antigen sandwich time-resolved fluorescence immunoassay method for detection of peste des petits ruminants virus(PPRV)was established.[Results]The method has high sensitivity and specificity and can specifically detect the antibody against PPRV in sheep serum,and it has no cross reaction with other related diseases.The method was used to detect 292 clinical samples,and compared with French IDVET competition ELISA kit.The coincidence rates of positive samples and negative samples from the two kinds of test kits were 92.47%and 97.26%,respectively,and the overall coincidence rate was 94.86%.The intra-group and inter-group coefficients of variation in the repeatability test were less than 10%.[Conclusions]Compared with the traditional ELISA method,the double-antigen sandwich time-resolved fluorescence immunoassay for detection of PPRV has equivalent sensitivity and specificity,and simple and rapid operation,and thus high application and popularization value.

基于LIBS技术的SCR催化剂成分检测

【目的】火电厂SCR催化剂运行一段时间后,由于烟气冲蚀、氯与钒发生反应等,催化剂中的活性成分V_(2)O_(5)流失和载体TiO_(2)、结构助剂WO_(3)含量改变,催化剂活性下降。因此,催化剂成分含量的检测对于SCR脱硝系统的安全经济运行具有重要意义。【方法】通过实验室配制7个催化剂定标样品,采用激光诱导击穿光谱技术装置进行检测,通过多元线性回归得到V_(2)O_(5)、WO_(3)、TiO_(2)质量百分含量和各自特征谱线强度之间的定标曲线方程。再对8号样品(现场取样的新鲜催化剂)进行测量,验证测量的准确度。【结果】结果表明,8号样品中V_(2)O_(5)、WO_(3)、TiO_(2)测量值与实际值的相对误差r分别为:2.7%、1.5%、1.6%,相对误差值均小于5%,测量精度较高。【结论】为SCR催化剂成分的测量提供了一种新的、有效的检测方法,可为催化剂的更换、再生管理及火电厂脱硝系统的安全经济运行提供重要保障。

基于LIBS的SCR催化剂活性成分快速检测研究

SCR催化剂对于NOx的催化还原效率下降主要源于烟气的侵蚀,以及烟气中氯(Cl)与钒(V)发生反应生成挥发性氯化钒,导致催化剂的活性成分流失所致。所以,快速准确地检测催化剂中的活性成分是催化剂制备和失活诊断的重要工作。本文基于激光诱导击穿光谱技术(LIBS),提出一种快速检测电厂SCR催化剂中V和钨(W)的含量的方法。实验中,采用波长为1064nm的Nd:YAG脉冲激光器作为激发源,并采用CCD光谱仪实现激光诱导催化剂样品的等离子体发射光谱信号的采集。为了提高检测准确度及重复性,实验样品是采用高纯度的V2O5、WO3、TiO2(纯度高于99%)制备而成。通过对实验参数如延迟时间、烧蚀光斑尺寸,以及数据处理方法的优化,实验样品的LIBS分析准确度较高,验证样品W和V元素含量相对误差低于5%。实验结果表明,在钒浓度为0.1-1.3%,钨浓度为0.8-9.5%时,LIBS检测的相对标准偏差为8%。研究结果表明本文所提出的方法可以实现电厂SCR催化剂中V和W含量的快速准确检测。