Analysis of metallic elements dissolution in the Astragalus at different decocting time by using LIBS technique

Astragalus is an important traditional Chinese herb that has therapeutic potential in the treatment of diseases. In this study, the dissolution of metallic elements during the material decoction process was investigated using laser-induced breakdown spectroscopy(LIBS). The Ca, Mg, Al, and Fe in the drug residues, liquid, and vapor were selected for the study of the transfer of elements after different decocting times. It was found that the intensities of the spectral lines for these elements in the drug liquid increased with increasing decocting times.The contrast trend was observed in the residues and only calcium was detected in the vapor.Furthermore, the relative mass concentrations of Ca, Mg, Al, and Fe in the liquid were quantitatively determined by a combination of the standard addition method and calibrationfree-LIBS method by adding the standard concentration solution of Cu and Cd elements into the drug liquids, it can be found that the maximum error between Cd concentration calculated by internal CF-LIBS and the standard is within 10%. This provides a new method of achieving the on-line monitoring and analysis of metallic elements in the production of traditional Chinese medicines.

Qualitative and semi-quantitative analysis of health-care pharmaceutical products using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS) is a sensitive optical technique that is capable of rapid multi-elemental analysis. The development of this technique for elemental analysis of pharmaceutical products may eventually revolutionize the field of human health. Under normal circumstances, the elemental analysis of pharmaceutical products based on chemical methods is time-consuming and complicated. In this investigation, the principal aim is to develop an LIBS-based methodology for elemental analysis of pharmaceutical products. This LIBS technique was utilized for qualitative as well as quantitative analysis of the elements present in Ca-based tablets. All the elements present in the tablets were detected and their percentage compositions were verified in a single shot, using the proposed instrument. These elements(e.g., Ca, Mg, Fe, Zn, and others) were identified by the wavelengths of their spectral lines, which were verified using the NIST database. The approximate amount of each element was determined based on their observed peaks and the result was in exact agreement with the content specification. The determination of the composition of prescription drug for patients is highly important in numerous circumstances. For example, the exploitation of LIBS may facilitate elemental decomposition of medicines to determine the accuracy of the stated composition information. Moreover, the approach can provide element-specific, meaningful, and accurate information related to pharmaceutical products.

Multiple grain-size fraction analysis of heavy minerals and the provenance identification of sediments from the abandoned Huanghe River,eastern China

The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.

电化学富集-激光诱导击穿光谱(LIBS)法测定水中铀元素

为改善激光诱导击穿光谱技术(Laser-Induced Breakdown Spectroscopy,LIBS)检测液体样品时遇到的液体飞溅、等离子体猝灭和稳定性差的问题,结合电化学富集方法,以KCl为电解质,石墨棒为阴极,开展了水中铀(U)元素的LIBS检测研究。选择UⅡ367.007 nm、UⅡ409.013 nm作为分析对象进行定量分析,着重研究了富集电压、KCl质量浓度、激光脉冲能量、激发方式等对铀元素特征谱线强度的影响规律,并通过扫描电子显微镜(SEM)及能谱分析(EDS)对石墨棒表面吸附元素的空间分布进行了分析。结果表明,最佳富集电压为1.6 V,适当的电解质KCl质量浓度可以提高铀元素的富集效率和富集均匀性,提高激光脉冲能量与采用光电双脉冲激发方式能增强铀元素特征谱线的强度并提高信噪比。在光电双脉冲激发下,对水中铀元素进行了定量分析,获得UⅡ367.007 nm、UⅡ409.013 nm的检测下限分别为25.89和15.00μg/L,相关系数均大于0.98。方法可为水体中放射性核素含量调查、生活饮用水铀污染现状以及核工业含铀废水监测等场景提供技术支持。

我国来华留学生教育政策内容的量化研究

来华留学生教育政策是持续有效推动“留学中国”品牌打造的制度力量,研究来华留学生教育政策有助于明晰政策制定的现状和后续改进的方向。通过构建“教育政策工具—教育发展要素”二维分析框架,并对2000年以来4份具有代表性的来华留学生教育政策文本进行整理、编码和量化分析发现,我国来华留学生教育政策的发展呈现出阶段性特点,在教育政策工具和教育发展要素的分布上存在不同程度的过溢、不足或缺失。为此,应增加激励、能力建设和系统变革工具的运用,加强师资和教学资源建设的政策供给,增强教学研究和教学质量环节的政策供给力度。

碳酸盐工厂的精细刻画:定量化重建视角

【意义】碳酸盐工厂为碳酸盐岩沉积体系提供了物质基础,与海洋演化、元素循环、表生地质过程等密切相关,是反映地球系统演化的重要环节。因此,定量化表征碳酸盐工厂及其主控因素是深入理解碳酸盐岩所记录的地质信息的关键。【进展】总结了半定量—定量表征碳酸盐工厂的研究方法进展,结合对沉积过程正演模拟方法的介绍,从定量重建的角度为精细刻画碳酸盐工厂提供了思路。【展望】针对碳酸盐工厂的研究,应在传统碳酸盐岩沉积学的基础上加深对其主控因素的定量评估,特别是直接影响生态的因素。但在套用基于碎屑岩沉积体系所建立的定量分析方法时,需要考虑碳酸盐岩与碎屑岩的差异,并进一步完善适用于碳酸盐岩的模型和分析方法。此外,在应用地球化学指标反演碳酸盐工厂及其主控因素时,要加强对成岩作用改造程度的定量评估,以降低成岩作用对地球化学信号的影响。而在开发和应用新的碳酸盐岩地球化学代用指标时,需明确其赋存或分馏机理,从而更准确地解读其所反映的古气候和古环境信息。同时,在利用沉积过程正演模拟研究工厂的演化和生产机制时,需评估从现代环境中获取的参数在深时地质记录中的适用性,并在建模过程中考虑早期成岩作用及海水化学演化的影响。

基于稀土掺杂上转换纳米材料NaYF_(4):Yb,Er@TGA直接对金属离子进行定量分析的方法探究

目的:基于荧光猝灭或增强机制,构建稀土掺杂上转换纳米材料NaYF_(4):Yb,Er@TGA直接对金属离子进行定量分析的方法,实现对金属离子快速、准确、灵敏检测。方法:通过溶剂热法制备出性能优良的稀土掺杂上转换纳米材料NaYF_(4):Yb,Er@TGA,并对其进行表征;通过测量14种常见的金属离子对NaYF_(4):Yb,Er@TGA荧光强度的影响,筛选能够引起NaYF_(4):Yb,Er@TGA荧光强度增强或下降,且与金属离子浓度呈线性关系的金属离子类型,进而建立检测新方法。结果:金属离子Mg^(2+)、Fe^(3+)分别在浓度范围为0~7.00μg/mL、0~6.00μg/mL与NaYF_(4):Yb,Er@TGA的荧光强度呈现良好的线性关系,其标准曲线方程的线性系数分别为0.9924、0.9982,检出限分别为1.79μg/mL、1.30μg/mL,加标回收率分别为95.5%~98.8%、92.5%~97.8%,方法相对标准偏差分别为4.05%、8.18%。结论:该方法检测限低、准确度较高、精密度较好,有望用于实际样品中Mg^(2+)、Fe^(3+)定量分析。

横向载荷与预紧力对螺栓断裂寿命的影响

螺栓连接依靠自身简单可靠的特点被广泛应用于各个行业,然而螺栓的疲劳断裂却是一个非常突出的问题.因此,为准确预测螺栓断裂失效寿命,进行了螺栓材料的疲劳裂纹扩展实验,求得了螺栓材料的断裂参数,从而建立了Paris裂纹扩展模型.然后运用有限元方法与疲劳裂纹扩展实验进行对标,并取得较好的效果,为螺栓断裂失效寿命的计算奠定了基础.最后,考虑到螺栓预紧力与横向载荷对螺栓断裂的影响,建立了带裂纹的螺栓有限元模型,并采用有限元方法进行螺栓失效寿命计算的定量分析.结果表明:横向载荷与螺栓预紧力对应力强度因子和螺栓使用寿命具有较大的影响.

激光诱导击穿光谱技术在光谱数据的增强和定量分析上的基础研究

激光诱导击穿光谱技术(Laser-Induced Breakdown Spectroscopy, LIBS)是一种通过脉冲激光聚焦样品产生等离子体,对等离子体发射光谱进行分析进而得到物质成分和含量的一种原子发射光谱技术。LIBS由于其成本低、适用范围广、样品无需复杂的预处理、检测速度快且可实现原位检测等特点成为了元素分析的一大热门,在工业、环境保护、生物医学、珍贵物品鉴定、军事等领域都有着很好的应用前景。但在分析元素种类与含量时,对光谱结果的分析常会受到基体效应、自吸收效应、等离子体屏蔽效应等因素的影响,使得提高LIBS技术的精确度成为了一大议题。本文基于LIBS的简介和基本原理和技术优点,详细分析了LIBS现阶段存在的问题及光谱增强的途径,并综述了定量分析的指标和方法,为LIBS更精确的检测提供了更多途径。

不同品种橡胶籽中氨基酸及无机元素定性与定量分析

橡胶籽作为橡胶树的副产物在很长一段时间里仅少量被用来育种,大部分均未被开发利用。本文利用ICP-MS等设备对不同品种橡胶籽中的氨基酸和无机元素进行定性和定量分析,比较不同品种橡胶籽中氨基酸和无机元素种类与含量的差异,从而为下一步的研究及橡胶籽产品的开发提供理论依据。测定分析结果表明,橡胶籽中含有赖氨酸、组氨酸、缬氨酸、苏氨酸、亮氨酸、苯丙氨酸等饲料必需氨基酸,适合作动物性饲料的原料;不同品种橡胶籽中均含有较丰富的无机元素,其与品种等因素具有一定的相关性。因此,橡胶籽可用于植物蛋白粉和优质蛋白饲料的生产。

激光溅射电离飞行时间质谱快速定量分析钛合金中的氢

本研究使用自行搭建的激光溅射电离飞行时间质谱(LAI-TOF MS)对钛合金标准样品进行检测,建立了钛合金中氢的直接定量分析方法,得到氢元素标准曲线的线性关系良好,线性相关系数0.9913,检出限低至0.0004%,计算得到氢元素的原子化和离子化效率约为13.4%。将该方法应用于其他钛合金样品中氢元素的分析,氢测定值相对标准偏差(RSDs)均小于14%;将该测定结果与惰性气体熔融-红外法测定值进行对比,相对误差均在5%以内。同时,通过分析LAI-TOF MS谱图,可实现钛合金样品中Be、C、Al、Si、P、Ca、Cr、Fe、Zr、Mo、Pd、In、Sn等微量元素的定性和半定量检测。结果表明,基于LAI-TOF MS建立的钛合金中氢定量检测方法几乎无需样品前处理、操作简便、分析时间短、灵敏度高,可用于钛合金中氢元素的快速直接定量检测。

波长色散X射线荧光光谱在石油炼制与化工催化剂研究中的应用

阐述了X射线荧光光谱(XRF)技术的发展历程,概述了XRF原理和分析过程;从X射线管、探测器、测角仪等方面介绍了波长色散XRF(WD-XRF)组件及最新技术发展情况,阐述了XRF技术在催化剂分析中的应用及重要性。简述了XRF定性和定量分析方法;介绍了2种常用的样品制备方法——粉末压片法和熔融法;概述了前处理过程对XRF定量分析结果准确性的影响。从催化裂化催化剂、加氢催化剂、重整催化剂、分子筛等方面分类总结归纳了波长色散XRF在炼油化工催化剂分析中的应用情况及进展,并对未来XRF技术的发展进行了展望。

药用辅料甘油三乙酯中7种ICH控制元素测定方法的建立

目的建立电感耦合等离子体质谱法(ICP-MS)测定药用辅料甘油三乙酯中钒(V)、钴(Co)、镍(Ni)、砷(As)、镉(Cd)、铅(Pb)、汞(Hg)元素的含量。方法样品经微波消解处理后,按拟订的仪器工作条件,采用ICP-MS法进行测定,并通过在线加入内标元素来校正测量结果。结果各元素在1~50 ng·mL^(-1)与响应值线性关系良好(r在0.998~0.999);回收率均在80.7%~105.8%(n=6)。结论本方法准确度高、重现性好,可用于药用辅料甘油三乙酯中多种元素杂质的含量测定。

ICP-MS分析在矿产中金属元素的定量检测

为确定金属矿产资源是否值得开发利用,应当使用科学合理的金属元素定量检测方法。不同金属矿产资源所存储的地质环境不同,导致金属元素含量存在一定的差异性,就算相同矿产资源的金属元素含量上也存在不同,这就需要更为精确的定量检测方法。而ICP-MS是可以针对复杂性元素的分析技术,体现出元素含量测定快的特点,使其广泛应用在金属矿产资源中的金属元素测定工作,从而对明确矿产资源品质提供依据。因此,在矿产资源金属元素定量检测中,应该加大对ICP-MS分析方法的使用,有利于掌握矿产资源的金属元素含量,更好为矿产资源开发企业带来经济效益。本文通过对ICP-MS概述,阐述了ICP-MS分析在矿产中金属元素的应用,也对相应实例分析,为ICP-MS分析在矿产中金属元素的定量检测提供参考。

曲线现浇箱梁非对称恒载对桥梁动静力响应影响的量化研究

为量化研究曲线现浇箱梁非对称恒载对桥梁动静力响应的影响,首先推导了非对称恒载偏心扭矩的计算,然后选取常规跨径16、20、30、40m及平面曲线半径30、50、100、200m,建立12组等高三跨现浇连续箱梁桥为研究样本.基于Python语言建模、MIDAS/Civil软件进行有限元分析,研究考虑非对称恒载扭矩与否两种情况对曲线现浇箱梁桥支座反力、主梁应力和下部结构内力的影响.结果表明,非对称恒载扭矩引起支座反力外大内小、影响显著且边墩反力受影响程度大于中墩;当桥梁平面曲线半径为30m内时,非对称恒载对曲线箱梁桥梁体应力影响显著,半径达100m后可不考虑非对称恒载对梁体应力的影响;非对称恒载对桥墩安全度的影响极为有限,地震作用下桥墩承载力计算可不予考虑.

Quantitative analysis results of CE-1 X-ray fluorescence spectrometer ground base experiment

As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of the quasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer （CE-1/XFS） aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented.

Investigation on Thermal and Dimensional Stability of Epoxy Resin In-Situ Modified by Cyanate Ester Resin and Polydimethylsiloxane

The thermal and dimensional stability of epoxy resin(EP)in-situ modified by cyanate ester(CE)and polydimethylsiloxane(PDMS)are investigated by means of experiments and numerical simulation.Thermal gravimetric analysis(TGA)and differential scanning calorimeter(DSC)are used to analyze the heat resistance of the modified EP.The dimensional stability is characterized by the volume shrinkage of the series PDMS/CE/EP obtained by the density method.The chemical structure of the PDMS/CE/EP is analyzed by Fourier transform infrared spectroscopy(FTIR).The results of TGA and DSC indicate that the thermal stability of PDMS/CE/EP decreases firstly and then increases with the increase in the amount of CE.The addition of PDMS shows a slight effect on the thermal stability.The 40%CE makes the blending system exhibit the lowest initial decomposition temperature,which reduces by 15.5%and 40.8%compared with pure EP and CE,respectively.The FTIR results suggested that the influence of CE on the thermal stability of the modified EP is mainly ascribed to the generation of oxazolidinone ring with low thermal stability and the increase in the triazine ring with high thermal stability.The volume shrinkage measurement results show that the introduction of CE and PDMS are both beneficial to the improvement of the dimensional stability of the blending systems.The in-situ addition of 80%CE shows the lowest volume shrinkage of6.11%.The thermal stress distribution of PDMS/CE/EP generated during the solidification process is simulated by the finite element analysis.The results suggested that the introduction of 80%CE into EP results in the lowest thermal stress in the blending system,which indicates that the system has the lowest volume shrinkage,which agrees well with the experimental results.

基于激光诱导击穿光谱技术的深海稀土元素识别与定量分析探索

深海稀土在世界大洋中广泛分布,其资源潜力巨大。我国是最早开展深海稀土调查的国家之一,引入新技术、新方法有助于未来海洋稀土资源的开发与利用。激光诱导击穿光谱(LIBS)作为一种新型的海洋原位探测技术,具备深海稀土原位分析的能力。本文将LIBS技术引入深海沉积物稀土元素的探测与分析中,以富稀土深海沉积物标准物质(GBW07586~GBW07590)为研究对象,识别出16种稀土元素(Pm除外)的LIBS特征光谱峰,并以此验证了LIBS用于La等6种稀土元素的定量分析能力,可实现ppm量级的灵敏检测。本文阐述了LIBS技术面向深海稀土矿检测的适用性,研究结果将为未来LIBS深海稀土原位探测提供重要依据,为深海稀土资源评估与开采提供支撑。

定量CT有限元分析椎体强化对不同位置非强化椎生物力学参数的影响

背景:骨水泥与骨质疏松椎体间在生物力学特性上的巨大差异是否会增加再骨折的发生还存有争议。骨水泥的置入将导致多大范围的非强化椎生物力学参数改变仍然不清楚。目的:通过以定量CT为基础的长节段骨质疏松性椎体压缩骨折有限元模型,分析椎体强化对于骨质疏松脊柱生物力学参数的影响范围。方法:以定量CT数据为基础构建T4-L5长节段T12椎体骨质疏松性压缩骨折模型,在对模型施加150 N垂直载荷的基础上,沿不同方向分别施加1.5 N·m的扭力矩以模拟前屈、后伸、左右侧屈及左右旋转状态,比较骨水泥置入前后模型椎体、椎间盘及小关节的应力变化。结果与结论:(1)模型骨水泥置入后,各个运动状态下整体位移幅度平均下降约16%;(2)强化椎近端5个椎体应力较术前平均增加约20%,头端第一椎间盘应力较术前下降约20%,第二、第三椎间盘应力则分别增加约4%及2%;强化椎及其尾端邻椎小关节应力较术前下降约6%,其余尾端小关节及头端相邻4个节段小关节应力均较术前不同程度增加;并且这种应力改变均表现为距强化椎越近变化越显著的趋势;(3)结果表明椎体强化将导致强化椎头尾端多个椎体、椎间盘及小关节应力的显著改变,且距强化椎越近改变越明显,这种应力改变可能与椎体强化后再骨折的发生有关。

低品位碳酸锰矿工艺矿物学研究

采用XRF、XRD、AMICS、EPMA等多种测试手段,对贵州某地锰矿矿石进行了系统的工艺矿物学研究,包括化学成分分析、矿物组成及含量分析、主要元素的赋存状态研究、主要矿物的嵌布特征和嵌布粒度研究。矿物含量研究在XRD和AMICS半定量分析基础上,通过使用XRF和EPMA校正数据,提高数据的准确性。研究表明,该矿石为低品位中高铁高磷酸性锰矿石,矿石中有用矿物为钙菱锰矿,主要脉石矿物为锰白云石、锰菱铁矿、伊利石、石英、钠长石、黄铁矿及磷灰石。代表性样品w(MnO)为18.74%,其主要赋存于钙菱锰矿中。钙菱锰矿的百分含量为38.71%,95.00%的Mn赋存其中。钙菱锰矿嵌布粒度主要集中在37.50~178.38μm区间,而脉石矿物的嵌布粒度主要集中在0.83~37.50μm区间。