Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

Apply X-Ray Fluorescence and γ-Ray Spectroscopy to Analyze Igneous and Sedimentary Environmental Samples of Al-Atawilah (Al-Baha), Saudi Arabia

Igneous and sedimentary rocks contain an amount of natural radioactivity (NORM). U-238, Th-232 and their decay products, and K-40 are important sources of gamma-radiation. Knowledge of the radionuclide content of rocks is necessary to estimate the exposure of the population to the radiation. Many types of rocks are used in building and industries, thus the radiation detection is important, it provides a baseline map of levels of the radioactivity in the study region. The purpose of this study is to evaluate the activity concentrations of the natural radionuclides (U-238 (Ra-226), Th-232 and K-40) and the fallout nuclide (Cs-137) (if found) in thirty samples of igneous and sedimentary rocks of Al-Atawilah (Al-Baha). The samples were collected and prepared during 2018/2019, and analyzed with a good experimental instrument (High energy resolution γ-ray spectroscopy with HPGe detector), also these rock samples were analyzed with X-ray fluorescence to subdivided these rocks based on the major oxides proportions contained of each sample. The mean activity concentrations of naturally radionuclides were found in the igneous rock samples varied depending on the type of the igneous rock. For sedimentary rock samples, the activity concentrations were found high for quartz sandstone sample, which may be due to its high proportion of SiO2 and K2O. The estimated mean values of absorbed dose rate are within the permissible limit value. The findings indicate high dose level values in granite (rhyolite) and most of diorite (andesite) igneous rock samples while gabbro (basalt) igneous rock samples (except for one sample) record low levels of dose rate. All sedimentary rock samples have low dose rate (except for the quartz sand-stone sample).

A method for correcting characteristic X-ray net peak count from drifted shadow peak

To correct spectral peak drift and obtain more reliable net counts,this study proposes a long short-term memory(LSTM)model fused with a convolutional neural network(CNN)to accurately estimate the relevant parameters of a nuclear pulse signal by learning of samples.A predefined mathematical model was used to train the CNN-LSTM model and generate a dataset composed of distorted pulse sequences.The trained model was validated using simulated pulses.The relative errors in the amplitude estimation of pulse sequences with different degrees of distortion were obtained using triangular shaping,CNN-LSTM,and LSTM models.As a result,for severely distorted pulses,the relative error of the CNN-LSTM model in estimating the pulse parameters was reduced by 14.35%compared with that of the triangular shaping algorithm.For slightly distorted pulses,the relative error of the CNN-LSTM model was reduced by 0.33%compared with that of the triangular shaping algorithm.The model was then evaluated considering two performance indicators,the correction ratio and the efficiency ratio,which represent the proportion of the increase in peak area of the two characteristic peak regions of interest(ROIs)to the peak area of the corrected characteristic peak ROI and the proportion of the increase in peak area of the two characteristic peak ROIs to the peak areas of the two shadow peak ROI,respectively.Ten measurement results of the iron ore samples indicate that approximately 86.27%of the decreased peak area of the shadow peak ROI was corrected to the characteristic peak ROI,and the proportion of the corrected peak area to the peak area of the characteristic peak ROI was approximately 1.72%.The proposed CNN-LSTM model can be applied to X-ray energy spectrum correction,which is of great significance for X-ray spectroscopy and elemental content analyses.

微区X射线荧光光谱成像法分析历史文物建筑混凝土材料成分及工艺

历史文物建筑修复与保护的首要步骤是对建材构件进行成分解析。但成型的混凝土构件成分复杂,传统技术难以直接分析。微区X射线荧光光谱具有速度快、无需前处理、可获得大面积高分辨的元素成像等优势,可用于此类混合物的原位分析。采用束斑为20μm的微区X射线荧光光谱仪,扫描成型混凝土构件以获得混合成分的元素分布图,结合基本参数定量法,对典型历史建筑混凝土构件进行元素定量。分析结果有效地解析了混凝土构建中骨料和凝胶材料的成分和含量,鉴别了涂层成分,解析了拌混工艺,鉴别了局部污染元素和致劣元素并分析致劣原因,为历史建筑修复材料选配、拌混工艺选择、除污及保护性预防劣化提供了科学的数据支撑。

矿物药龙骨与伪品现代动物骨骼的对比研究

目的:从微观、图谱、化学成分上对龙骨进行真伪鉴定,为龙骨的质量控制和评价方法提供参考。方法:根据龙骨矿物特性,利用显微镜观察、近红外光谱、X射线荧光光谱仪进行鉴定研究,对比真伪品龙骨单偏光、正交偏光镜下特征,以正品龙骨的近红外光谱为参照,建立真伪龙骨定性鉴别模型,分析龙骨内元素检测结果。结果:正品龙骨呈磷灰石光学特性,与动物骨骼伪品龙骨有较大区别,正品较现代动物骨骼伪品P、Ca相对较少,但富集元素Sr、F,利用近红外特征谱段可建立有较好预测能力的相关系数模型。结论:偏光显微镜、近红外光谱法、X射线荧光光谱法可提高龙骨的真伪鉴别结果正确率。

温拌SBS改性沥青的流变特性及微观机理研究

将两种不同类型的温拌剂ACMP和XT-WY2分别加入到SBS改性沥青中,制备温拌SBS沥青,进行了黏度和高低温流变实验,并通过傅里叶红外光谱和荧光显微镜研究其微观形貌。结果表明,ACMP不利于沥青的高温性能,但与沥青的相容性较好,可以提升其低温性能,XT-WY2并未明显改变沥青的流变性能。两种温拌剂均为物理改性,都会提高SBS改性剂在沥青中的分散均匀性,但分散效果不尽相同。温拌沥青的微观参数荧光面积与其流变性能相关性很强,可反映其高低温性能。

高粘度改性沥青(HVMA)热老化机理及微观特性

以SBS改性沥青为原材料,通过高速剪切法制备了高粘改性剂掺量分别为0%、10%、14%的高粘度改性沥青(HVMA)。采用基本性能试验、傅里叶红外光谱(FTIR)试验、凝胶渗透色谱(GPC)试验及荧光显微镜(FM)试验,分析了不同掺量HVMA老化前后基本性能、化学组分和微观相态的变化。结果表明:掺入高粘改性剂可以增强沥青高温稳定性、低温抗裂性、抗变形能力以及抗老化能力。综合分析残余针入度(RP)、软化点增量(SPI)及残余延度(RD)得出HVMA-14抗老化性能最好;老化导致高粘度改性沥青羰基指数(CI)指数升高,聚合物指数(PI)指数降低,聚合物分子量减小,沥青质分子量增大;随着高粘改性剂掺量的增加,聚合物相由分散的点状结构逐渐变为连续的“空间网络”结构。老化后聚合物相结构遭到破坏,颜色变浅,轮廓变模糊,且连续相逐渐消失。

Analysis of nickel distribution by synchrotron radiation X-ray fluorescence in nickel-induced early- and late-phase allergic contact dermatitis in Hartley guinea pigs

Background: Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy. Methods: Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10%(sensitization-challenge;late phase group);10% NiSO4-group, 10% to 10%(sensitization-challenge;early-phase group);and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES). Results: In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (>200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni^2+ aqueous ionic state but in the nickel-binding protein. Conclusions: This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni^2+ aqueous ionic state but bound with certain proteins to form a complex in the stratum corneum in ACD model tissue.

Application and Development Trends of Spectral Analysis in Draft of Non-Ferrous Metal Standards in China

Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of various spectroscopic techniques, mainly including atomic absorption spectrometry (AAS) inductively coupled plasma emission spectrometry (ICP-AES) X-ray fluorescence spectroscopy (XRF) atomic fluorescence spectroscopy (AFS) direct reading spectroscopy (OES) glow discharge emission spectroscopy (GD-OSE) laser-induced breakdown spectroscopy (LIBS), in the formulation of non-ferrous metal standards in China. The AAS method was the most widely used single-element microanalysis method among the non-ferrous metal standards. The ICP-AES method was good at significant advantages in the simultaneous detection of multiple elements. The XRF method was increasingly used in the determination of primary and secondary trace elements due to its simple sample preparation and high efficiency. The AFS was mostly detected by single-element trace analysis. OES GD-OES and LIBS were playing an increasingly important role in the new demand area for non-ferrous metals. This paper discussed matrix elimination, sample digestion, sample preparation, instrument categories and other aspects of some standards, and summarized the advantages of spectral analysis and traditional chemical analysis methods. The new methods of future spectroscopic technology had been illustrated in the process of developing non-ferrous metal standards.

高温高压法合成钻石的宝石学特征

采用宝石显微镜、红外光谱仪、X荧光光谱仪、紫外荧光灯、Diamond View^(TM)等对济南某公司生长的高温高压合成的黄色、无色、蓝色钻石样品进行详细地测试与分析。结果表明,高温高压合成钻石放大观察可见内部含有棒状、柱状、细小微粒状的金属包裹体,个别样品内部相对纯净,净度级别可达VS_1;红外吸收光谱测试显示,无色合成钻石为IIa型,黄色合成钻石为Ib型,蓝色合成钻石为IIb型。X荧光光谱测试显示所有钻石都具有强烈的铁峰,无色和蓝色合成钻石未检出镍,5号样品检测出铁和镍,6号样品检测除铁和镍外还有锰。无色和蓝色合成钻石在Diamond View^(TM)下具有蓝白色荧光,并具有磷光现象且发光时间可达60多秒;合成黄色钻石在Diamond View^(TM)下具有黄绿色荧光,无磷光现象。这些高温高压合成钻石都具有"黑十字"现象,并可见四边形生长环带。紫外-可见光分光光谱仪测试合成钻石,均未检测到415nm吸收线。

济南高压高温合成钻石的宝石学特征

采用宝石显微镜、红外光谱仪、X射线荧光光谱仪、紫外荧光灯、DiamondView^(TM)等对济南某公司生长的高压高温合成的黄色、无色、蓝色钻石样品进行详细地测试与分析。结果表明,高压高温合成钻石放大观察可见内部含有棒状、柱状、细小微粒状的金属包裹体,个别样品内部相对纯净,净度可达VS1;红外吸收光谱测试显示,无色合成钻石为IIa型,黄色合成钻石为Ib型,蓝色合成钻石为IIb型。X射线荧光光谱测试显示所有钻石都具有强烈的Fe峰,无色和蓝色合成钻石未检出Ni,5号样品检测出Fe和Ni,6号样品检测出Fe和Ni外还有Mn。无色和蓝色合成钻石在DiamondView^(TM)下具有蓝白色荧光,并具有磷光现象且发光时间可达60多秒;合成黄色钻石在DiamondView^(TM)下具有黄绿色荧光,无磷光现象。这些高压高温合成钻石都具有"黑十字"现象,并可见四边形生长环带。紫外-可见分光光谱仪测试合成钻石,均未检测到415nm吸收线。

罗丹明B对DNA分子识别作用的研究

利用紫外可见分光光度计、荧光光度计及原子力显微镜测定罗丹明B与双链DNA的相互作用方式 ,探讨罗丹明B对DNA的识别模式和作用机制 。

GPCRs二聚体:功能和药理作用展望

G蛋白偶联受体是最大的膜受体超家族之一,参与调节多种生理过程,在信号识别及转导中具有重要作用,是医学研究与计划的焦点之一,但基于GPCRs单体的药物通常疗效欠佳、副作用较多。随着GPCRs二聚体的不断证实,二聚体不同于单体的内在疗效、配体选择及由变构调节引起的功能选择性,在临床疾病治疗及新药研发中倍受关注。本文基于检测GPCRs二聚体的技术,就GPCRs二聚体形成的决定因素、功能及药理学作用作一综述。

DNA与CdS-NH_2纳米粒子的相互作用研究

采用荧光光谱、紫外光谱(UV-vis)、圆二色谱(CD)、透射电镜(TEM)、原子力显微镜(AFM)、琼脂糖凝胶电泳等技术研究Cd S-NH2-EcoRI复合物与DNA的相互作用.研究发现:Cd S-NH2纳米粒子与p BR322DNA结合后会延迟EcoRI的酶切反应.DNA的曲率和纳米粒子的粒径都是影响结合作用的因素,曲率较大的环状DNA比线性DNA能更好地与纳米粒子结合,小粒径的Cd S-NH2纳米粒子则更易结合到DNA上.并研究了DNA与Cd S-NH2纳米粒子之间的作用机理.

中华民国三十四年中央银行纸币印刷颜料无损研究

法币在中国货币史特别是近代货币史上有着重要地位。1935年11月至1948年8月间,先后发行了15种从“壹分”到“壹萬圆”不同面额的法币,由中外十六家不同印刷公司承印,版别多达百余种。本研究利用超景深三维视频显微镜、激光显微共聚焦拉曼光谱仪和便携式X射线荧光光谱仪,对11枚1945年(中华民国三十四年)中央银行发行的壹仟圆法币的印刷颜料进行了无损研究。结果表明,红色部分(印章、冠字号、纹饰等)普遍使用了有机合成染料系列颜料红PR,而蓝色、绿色、棕色部分普遍使用了普鲁士蓝、铅铬黄和炭黑等颜料进行调配呈色。这些信息能够为纸币类文物的鉴别、保护修复以及相关研究提供依据。

Microstructure and Mechanical Property of Magnetron Sputtering Deposited DLC Film

A diamond-like carbon（DLC） film was deposited on YT14 substrate using magnetron sputtering（MS）. The surface morphologies, roughness and bonding spectra of obtained film were characterized using scanning electron microscopy（SEM）, atomic force microscopy（AFM）, and X-ray photoelectron spectroscopy（XPS）, respectively, and its mechanical property and bonding strength were measured using a nanoindentation and scratch tester, respectively. The results show that the C-enriched DLC film exhibits a denser microstructure and smoother surface with lower surface roughness of 21.8 nm. The ratio of C sp2 at 284.4 e V that corresponds to the diamond（111） and the C sp3 at 285.3 e V that corresponds to the diamond（220） plane for the as-received film is 0.36： 0.64, showing that the C sp3 has the high content. The hardness and Young＇s modulus of DLC film by nanoindentation are 8.534 41 and 142.158 1 GPa, respectively, and the corresponding bonding strength is 74.55 N by scratch test.

AFM and fluorescence spectrascopy investigation for disaggregation of existing Aβ fibrils by baicalein

The wavelength for the peak of fluorescence emission of thioflavin T（ThT） was changed from 445 nm to 481 nm when ThT was added in Aβ solution which indicating the β-sheet structure of Aβfibril.The significant decrease in the intensity of fluorescence at 481 nm was observed when the baicalein was added in mixed solution of Aβand ThT,suggesting that the depolymerization of Aβ fibrils happened and there were Aβ fibrils left to react with ThT to keep the initial fluorescence intensity.And the existing Aβ fibrils are disaggregated by baicalein in a time- and dose-dependent manner.AFM images of the morphologies of the Aβ_（1-42） fibrils obviously changed smaller and more dispersive when baicalein added indicating also the depolymerization of Aβ.The results demonstrate a basis for development of a potential herb drug candidate for the treatment of Alzheimer＇s disease（AD）.

A STUDY OF PET TIRE CORD TREATED BY LOW TEMPERATURE PLASMA

The process of treating the PET tire cord (210D/3×2) by low temperature nitrogen and airlow temperature plasma and dipping in RFL (resorcinol-formaldehyde-latex) adhesive system wasstudied.The H-pull test value can be improved from about 35 N/cm of untreated sample to 55N/cm of nitrogen plasma treated sample.The photograph of SEM demonstrates that the adhe-sion between nitrogen plasma treated tire cord and rubber has reached the strength of rubber.Airplasma treatment has bad effect on adhesion improvement.The mechanism of plasma treatment on the surface of the PET tire cord and the mechanism ofadhesion improvement are investigated by diffuse reflection infra-red spectrum and XPS (X-rayphotoelectron spectroscopy).From the spectral analysis,it is believed that the contribution to im-provement of the adhesion of the tire cord is the oxidation on the surface.The serious breaking ofthe chemical bonds on surface can cause the adhesion inferior.

Synthesis of SiC/graphene nanosheet composites by helicon wave plasma

We report an approach to the rapid, one-step, preparation of a variety of wide-bandgap silicon carbide/graphene nanosheet(Si C/GNSs) composites by using a high-density helicon wave plasma(HWP) source. The microstructure and morphology of the Si C/GNSs are characterized by using scanning electron microscopy(SEM), Raman spectroscopy, x-ray diffraction(XRD), x-ray photoelectron spectroscopy(XPS), and fluorescence(PL). The nucleation mechanism and the growth model are discussed. The existence of Si C and graphene structure are confirmed by XRD and Raman spectra.The electron excitation temperature is calculated by the intensity ratio method of optical emission spectroscopy. The main peak in the PL test is observed at 420 nm, with a corresponding bandgap of 2.95 e V that indicates the potential for broad application in blue light emission and ultraviolet light emission, field electron emission, and display devices.

Palaeodiet of Miocene Producers and Depositional Environments:Inferences from the First Evidence of Microcoprolites from India

This paper reviews research on coprolites from India,providing the first evidence of microcoprolites from the early Miocene(Aquitanian)Khari Nadi Formation sedimentary succession,exposed about 1.5 km northeast of the village of Kotada,Kachchh(Kutch)District,Gujarat State,western India.Morphometric and size comparisons(in a statistical framework)with known coprolites from the Mesozoic-Cenozoic successions of India(including those recorded herein)and globally suggest that fishes were the likely producers of the Kotada coprolites.Scanning electron microscopy confirms the presence of fish dental remains within the coprolites,while both Scanning Electron Microscopy(SEM)and Energy Dispersive X-ray Spectroscopy(EDS)reveal the phosphatic nature of the microscopic coprolite specimens(recorded herein)hinting that the producer(s)were predominantly carnivorous(ichthyophagous)in their diet.Furthermore,X-Ray Fluorescence(XRF)analysis of the host and associated lithologies allows us to deduce that the Kotada coprolites were deposited in a shallow marine environment,with possible aerial exposure of the host lithology occurring at some point after deposition.To the best of our knowledge,the present report is the first record of microscopic fish coprolites from India,as well as being the first from the Aquitanian of India and the oldest Neogene record from India.