Rapid online analysis of trace elements in steel using a mobile fiber-optic laser-induced breakdown spectroscopy system

A mobile fiber-optic laser-induced breakdown spectrometer(FO-LIBS) prototype was developed to rapidly detect a large quantity of steel material online and quantitatively analyze the trace elements in a large-diameter steel tube.Twenty-four standard samples and a polynomial fitting method were used to establish calibration curve models.The R~2 factors of the calibration curves were all above 0.99,except for Cu,indicating the elements' strong self-absorption effect.Five special steel materials were rapidly detected in the steel mill.The average absolute errors of Mn,Cr,Ni,V,Cu,and Mo in the special steel materials were 0.039,0.440,0.033,0.057,0.003,and0.07 wt%,respectively,and their average relative errors fluctuated from 2.9% to 15.7%.The results demonstrated that the performance of this mobile FO-LIBS prototype can be compared with that of most conventional LIBS systems,but the more robust and flexible characteristics of the FO-LIBS prototype provide a feasible approach for promoting LIBS from the laboratory to the industry.     

Quantitative analysis of steel and iron by laser-induced breakdown spectroscopy using GA-KELM

According to the multiple researches in the last couple of years, laser-induced breakdown spectroscopy(LIBS) has shown a great potential for rapid analysis in steel industry.Nevertheless, the accuracy and precision may be limited by complex matrix effect and selfabsorption effect of LIBS seriously. A novel multivariate calibration method based on genetic algorithm-kernel extreme learning machine(GA-KELM) is proposed for quantitative analysis of multiple elements(Si, Mn, Cr, Ni, V, Ti, Cu, Mo) in forty-seven certified steel and iron samples.First, the standardized peak intensities of selected spectra lines are used as the input of model.Then, the genetic algorithm is adopted to optimize the model parameters due to its obvious capability in finding the global optimum solution. Based on these two steps above, the kernel method is introduced to create kernel matrix which is used to replace the hidden layer's output matrix. Finally, the least square is applied to calculate the model's output weight. In order to verify the predictive capability of the GA-KELM model, the R-square factor(R~2), Root-meansquare Errors of Calibration(RMSEC), Root-mean-square Errors of Prediction(RMSEP) of GAKELM model are compared with the traditional PLS algorithm, respectively. The results confirm that GA-KELM can reduce the interference from matrix effect and self-absorption effect and is suitable for multi-elements calibration of LIBS.     

Characterization of the Delamination Defects in Marine Steel Using Laser-Induced Breakdown Spectroscopy

In this paper,two types of comparison analyses,bulk analysis and defect analysis,were carried out for marine steel.The results of laser-induced breakdown spectroscopy(LIBS)were compared with those of spark optical emission spectrometry(Spark-OES) and scanning electron microscopy/energy dispersion spectroscopy(SEM/EDS) in the bulk and defect analyses.The comparison of the bulk analyses shows that the chemical contents of C,Si,Mn,P,S and Cr obtained from LIBS agree well with those determined using Spark-OES.The LIBS is slightly less precise than Spark-OES.Defects were characterized in the two-dimensional distribution analysis mode for Al,Mg,Ca,Si and other elements.Both the LIBS and SEM/EDS results show the enrichment of Al,Mg,Ca and Si at the defect position and the two methods agree well with each other.SEM/EDS cannot provide information about the difference in the chemical constituents when the differences between the defect position and the normal position are not significant.However,LIBS can provide this information,meaning that the sensitivity of LIBS is higher than that of SEM/EDS.LIBS can be used to rapidly characterize marine steel defects and provide guidance for improving metallurgical processes.     

Quantitative analysis of C,Si, Mn,Ni, Cr and Cu in low-alloy steel under ambient conditions via laser-induced breakdown spectroscopy

A diode-pumped solid-state laser(DPSSL) with a high energetic stability and long service life is applied to ablate the steel samples instead of traditional Nd:YAG laser pumped by a xenon lamp,and several factors, such as laser pulse energy, repetition rate and argon flow rate, that influence laser-induced breakdown spectroscopy(LIBS) analytical performance are investigated in detail.Under the optimal experiment conditions, the relative standard deviations for C, Si, Mn, Ni, Cr and Cu are 3.3%–8.9%, 0.9%–2.8%, 1.2%–4.1%, 1.7%–3.0%, 1.1%–3.4% and 2.5%–8.5%,respectively, with the corresponding relative errors of 1.1%–7.9%, 1.0%–6.3%, 0.4%–3.9%,1.5%–6.3%, 1.2%–4.0% and 1.2%–6.4%. Compared with the results of the traditional spark discharge optical emission spectrometry technique, the analytical performance of LIBS is just a little inferior due to the less stable laser-induced plasma and smaller amount of ablated sample by the laser. However, the precision, detection limits and accuracy of LIBS obtained in our present work were sufficient to meet the requirements for process analysis. These technical performances of higher stability of output energy and longer service life for DPSSL, in comparison to the Q-switch laser pumped by xeon lamp, qualify it well for the real time online analysis for different industrial applications.     

Plasma diagnostics by optical emission spectroscopy on manganese ore in conjunction with XRD,XRF and SEM-EDS

Manganese (Mn) is an important industrial mineral. Information about the chemical and phase constitution along with the concentration of impurities presented in Mn ore is compulsory in assessing its suitability for different applications. We performed the qualitative and quantitative analysis of low-grade Mn ore (LGMO) using laser-induced breakdown spectroscopy (LIBS) in conjunction with x-ray diffraction (XRD), x-ray fluorescence (XRF) and scanning electron microscopy (SEM) coupled with energy dispersive x-ray electron spectroscopy (EDS). The optical emission spectra of the LGMO sample displayed the presence of Mn, Si, Ca, Fe, Al, Mg, V, Ti, Sr, Ni, Na, Ba and Li. The plasma parameters, electron temperature and number density were estimated using the Boltzmann plot and Stark broadening line profile methods and were found to be 7500 K±750 K and 8.18±0.8×10¹⁷ cm⁻³, respectively. Quantitative analysis was performed using the calibration-free LIBS (CF-LIBS) method and its outcome along with XRD, XRF and SEM-EDS data showed almost analogous elemental composition, while the LIBS method gave acceptably precise elemental analysis by detecting the low atomic number element Li besides V and Sr. The results obtained using LIBS for the LGMO exhibited its ability as a powerful analytical tool and XRF, XRD and SEM-EDS as complementary methods for the compositional analysis of complex low-grade mineral ore.     

Roadside dust contamination with toxic metals along industrial area in Islamabad,Pakistan

An investigation has been carried out to understand the contamination characteristics of roadside dust in the industrial area of Islamabad, Pakistan. The amounts of Si, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Pb, Zn, Ga, As, Se and Cd were determined from 95 roadside dust samples collected along the Islamabad industrial area using Proton Induced X-ray Emission （PIXE）. The results indicated that concentrations of all elements, except Cd, in the roadside dust were significant. The results of the enrichment factor show that the elementary composition of the roadside dust could be categorized as soil elements from the crust of the earth and elements from anthropogenic pollution. The high enrichment factors imply that elements such Cr, Cu, Pb, Zn, As, Se, Cd, Ni, Co and S came from anthropogenic activities. The source of metal contamination was identified using multivariate statistical analysis. It has been concluded that Ca, Sc, Ti, V, Mn and Fe mainly originate from crustal sources; Cr, Cu, Ni, Pb, Zn and Ga are associated with point-sources from industrial pollution/traffic; and S, Cl, K, As and Se are mainly related to oil/coal combustion.     

几种不同元素与45~#钢混合的耐蚀性比较

离子束混合对金属耐蚀性影响的研究已屡见报道。该技术以其固有的特点正引起人们的重视。已有一些报道肯定了它对金属腐蚀研究的作用。 4S~#钢是一种用途广泛的碳素钢。本文用离子束混合技术将Cr、Ti、Mo和Cr+Ni等元素分别引入其基体,企图形成不同的表面新合金,以观察其对基体腐蚀性能的影响。用线性极化法评价各试样在充气的3％NaCl溶液中的腐蚀速率;在0.5mol/1 H_2SO_4和3％NaCl溶液中分别测试了各试样的阳极极化曲线,比较了它们在这两种介质中的电化学行为。     

Trace elements of soil samples from mining area

The affect of mining activity on the environment has been long of public concern. The present paper deals with the elemental analysis of soil samples from a mine and the area around it, located in E 48°59′ and N 34°11′ in Hamadan province of Iran. Elemental analysis was done using Proton Induced X-ray Emission (PIXE) technique. Spectra analysis and quantification was done using GUPIX software. Besides the major elements Si, P, K, Ca, Mn and Fe the other elements, namely Cl, Ti, V, Cr, Co, Ni, Cu, Zn, Rb, Sr and Pb were also present. Arsenic could be detected in some samples only. The presence of Ba and Ce needs more investigations by other techniques due to overlap of the L X-rays of these elements with the K X-rays of the major elements Mn and Fe, etc. Many elements V, Cr, As and Pb are known to be toxic and needs further understanding and proper handling in the mining process.     

9Cr3W低活性马氏体钢微观组织及力学性能的初步研究

通过提高W含量，调整V、Ta、Ti、N等微合金元素含量，设计了9Cr3W型低活性马氏体钢。研究了该钢的微观组织结构与硬化、时效及相转变行为，对其进行了拉伸性能和冲击韧性测试。与Eurofer97钢相比，该钢表现出优良的高温拉伸性能。分析了9Cr3W钢用作超临界水堆堆芯内部件及包壳材料的可行性，其高温力学性能远优于Zr合金包壳材料;拉伸性能与T91钢相当，且韧脆转变温度低于T91钢，冲击吸收功上限高于T91钢，具有优良的冲击韧性;9Cr3W钢的高温瞬时强度低于奥氏体316不锈钢，成为制约其用于超临界水堆堆芯内部件及包壳的因素之一。     

Ultrasonic Nebulizer Assisted LIBS: a Promising Metal Elements Detection Method for Aqueous Sample Analysis

A newly developed approach for trace metal elements detection for aqueous samples analysis is presented in this paper. The idea of this approach is to improve ablation efficiency by transforming the liquid sample into a dense cloud of droplets using an ultrasonic nebulizer. The resulting droplets are then subjected to analysis by laser induced breakdown spectroscopy (LIBS). A purpose-built ultrasonic nebulizer assisted LIBS (UN-LIBS) system has been applied to the analysis of aqueous samples at trace levels of concentration. Experimental investigations of solution samples were carried out with various dissolved trace metal elements (Mn, Zn, Cu, Pb, Fe, Mg and Na) using this approach. The characteristics of UN-LIBS signal of the elements were investigated regarding the lifetime and S/B ratio and the calibration curves for trace metal elements analyses. The obtained LODs are comparable or much better than the LODS of the reported signal enhancement approaches when the laser pulse energy was as low as 30 mJ. The good linearity of calibration curves and the low LODs shows the potential ability of this method for metal elements analysis application. The density of the electrons was calculated by measuring the Stark width of the line of Hα. The possible mechanism of the LIBS signal enhancement of this approach was briefly discussed.     

Trace element load in cancer and normal lung tissue

Samples of malignant and benign human lung tissues were analysed by two complementary methods, i.e., particle induced X-ray emission (PIXE) and total reflection X-ray fluorescence (TRXRF). The concentration of trace elements of P, S, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Sr, Hg and Pb was determined in squamous cancer of lung tissue from 65 people and in the benign lung tumour tissue from 5 people. Several elements shows enhancement in cancerous lung tissue of women in comparison to men, i.e., titanium show maximum enhancement by 48% followed by Cr (20%) and Mn (36%). At the same time trace element concentration of Sr and Pb are declaimed by 30% and 20% in women population. Physical basis of used analytical methods, experimental set-up and the procedure of sample preparation are described.     

双束同时辐照低活性Fe-Cr-Mn(W、V)合金微观组织损伤的影响

研究了时效热处理低活性Fe Cr Mn(W、V)钢双束同时辐照损伤行为 ,结果表明 :92 3K/ 3 0 0 0h时效合金 ,经单独电子辐照 (1 0a- 1)出现低密度空洞 ,而经双束同时辐照的时效合金 ,在辐照初期就形成间隙型位错环和微小空洞。与无时效合金相比 ,随时效温度增加 ,空洞尺寸、空洞密度和空洞肿胀量增大。随时效温度的提高碳化物析出数量增多 ,奥氏体中合金元素Cr、Mn、W、V降低 ,He的存在有效地促进空洞肿胀量增大。     

基于SRXRF的单个流体包裹体无损分析及其在石油地质中的应用

本文叙述了同步辐射X射线荧光微探针用于单个流体包裹体无损分析研究的实验装置和方法，通过测定NIST612标样，计算了目前实验条件下部分元素的检出限，对取自我国西部含油气盆地的典型有机包裹体作无损成分分析，给出了K，Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Rb,Sr,Y,Zr,Ba,Pb等元素的半定量测试结果，并对分析结果在石地质中的应用进行了初步研究。     

阿伦德陨石中壳层球粒的仪器及放射化学中子活化分析

本文中介绍了对阿伦德(Allende)陨石中4个壳层球粒的核部和壳部所做的仪器中子活化分析和放射化学中子活化分析工作,测定了8个(4对)样品的25个痕量元素。分析结果表明,元素在球粒核部和壳部具有不同的分布特征,这一结果为研究球粒的成因提供了进一步依据。     

Calibration curve and support vector regression methods applied for quantification of cement raw meal using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS) is a qualitative and quantitative analytical technique with great potential in the cement industrial analysis. Calibration curve(CC) and support vector regression(SVR) methods coupled with LIBS technology were applied for the quantification of three types of cement raw meal samples to compare their analytical concentration range and the ability to reduce matrix effects, respectively. To reduce the effects of fluctuations of the pulse-to-pulse, the unstable ablation and improve the reproducibility, all of the analysis line intensities were normalized on a per-detector basis. The prediction results of the elements of interest in the three types of samples, Ca, Si, Fe, Al, Mg, Na, K and Ti, were compared with the results of the wet chemical analysis. The average relative error(ARE),relative standard deviation(RSD) and root mean squared error of prediction(RMSEP) were employed to investigate and evaluate the prediction accuracy and stability of the two prediction methods. The maximum average ARE of the CC and SVR methods is 34.62% instead of 6.13%,RSD is 40.89% instead of 7.60% and RMSEP is 1.34% instead of 0.43%. The results show that SVR method can accurately analyze samples within a wider concentration range and reduce the matrix effects, and LIBS coupled with it for a rapid, stable and accurate quantification of different types of cement raw meal samples is promising.     

上海市钢铁工业尘单颗粒分析

用高分辨率、高灵敏度的扫描质子微探针对上海市工业尘进行单颗粒分析,研究了在颗粒物中不同元素的分布以及元素平均含量随粒径大小的变化。结果表明,Fe、Cr、Mn等元素在颗粒物中均匀分布的,而K、Ca则富集在颗粒物的表面。而且这些元素的平均含量随粒径的变化呈现出一规律性,其中大部分重金属元素（如Cu、Cr、Ni、Zn、Pb）聚集在颗粒粒径＜5μm的颗粒物上。     

Inelastic Scattering of 14MeV Neutrons by Medium Weight Nuclei

Continuous spectra of neutrons inelastically scattered from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge and As have been measured at an incident energy of 14 MeV with good statistics. Time-of-flight technique was used. In the analyses there were used three sets of inverse-reaction cross section σ_i: (1) calculated with Perey-Buck potential, (2) with Bjorklund-Fernbach potential and (3) cross section assumed to be constant. The inverse-reaction cross section does not affect appreciably the values of nuclear temperature or nuclear level density parameter for these nuclei except Ti, V and Cr. The nuclear temperature was found to be nearly constant in the mass number region of 48–75. The level density parameter as a function of mass number follows the general trend suggested by Newton. Newton's coefficient is found to be 0.092, in agreement with values obtained in other experiments. The total inelastic scattering cross sections are derived.     

古代青金石颜料的质子激发X荧光分析

用质子激发Ｘ荧光分析（ＰＩＸＥ）方法分析了敦煌莫高窟、麦积山石窟、炳灵寺石窟的１１个朝代壁画中所使用的青金石颜料，获得了该颜料的定性定量分析结果．通过对１８个样品的分析对比，对青金石颜料中所含的Ｍｎ、Ｃｒ、Ａｓ、Ｔｉ、Ｓｒ、Ｓｂ、Ｚｎ等微量元素作了讨论，并与Ｘ射线荧光（ＸＲＦ）、Ｘ射线衍射（ＸＲＤ）、电子探针分析结果作了对比．     

Determination of trace elements by instrumental neutron activation analysis in Anatolian bentonitic clays

Instrumental Neutron Activation Analysis (INAA) was carried out for the determination of trace elements in non-swelling type bentonitic clays. Samples were irradiated in Triga Mark II type of reactor at the Nuclear Institute of Technical University of Istanbul. Irradiation was performed in two steps for “short and long lived” isotopes. The γ spectra of short lived isotopes were interpreted with respect to Al, Ca, Mg, Na, K, Ti, Mn, V qualitatively and that of long lived isotopes with respect to Sc, Cr, Br, Sb, Cs, La, Ce, Sm, Yb, Hf quantitatively. The relative richness of the trace elements (Al, Ti, Ca, Mg, Na, K) observed in the Sampo 90 program was obtained using Atomic Absorption technique by normalizing its value to that of sodium. The silicon content of samples was determined by gravimetry. The results indicated that Sample I contained relatively higher amount of REE, Sb, Ca and Na than Sample II. The amount of Sc, Cr and Br were about similar in both samples. Concentrations of La, Ce, Sm and Yb are higher than REE abundances found in all natural waters. These results suggest that Ca-bentonite samples are representative of primary deposition environment. In addition, the Sc content of both the samples indicates that Ca-bentonite deposits originated from continental crust. The relatively high amount of REE might bring about porosity problems in the use of Ca-bentonite in cement and concrete production.