基于K均值算法的X射线荧光光谱法检验药用铝塑包装片的研究

药用铝塑包装片是犯罪现场勘查过程中常见的物证,研究建立一种准确检验药用铝塑包装片种类的方法,可为法庭科学领域现场物证检验提供技术支撑.实验利用X射线荧光光谱仪(XRF)对30个不同品牌、不同厂家的药用铝塑包装片样品进行测定,按照元素含量对样品初步分组,用Pearson相关系数和假设检验分析样品的相关性;运用Python...     

X射线荧光光谱法测定陶瓷材料

文章使用日本理学 30 6 3PX射线荧光光谱仪 ,采用熔融制样方法 ,用经验系数校正基体效应 ,测定了陶瓷材料中的 8种元素。方法简便、快速、准确     

X射线荧光光谱法结合双标图对IC卡的检验

针对电信诈骗案件中常见的IC卡类物证,建立了一种分类方法.使用手持式X射线荧光光谱仪(XRF)对40个不同来源的IC卡样品进行了检验研究.根据IC卡样品中无机元素成分含量的不同,使用双标图对样品进行分类,结果显示为6类.为判断分类结果的科学准确性,利用系统聚类分析方法处理样品的XRF数据.结果 表明:当并类距离为2时,...     

X射线荧光光谱法定量测定湿法磷酸

湿法磷酸样品经稀盐酸分解后,在X射线荧光光谱仪上采用液体样品杯直接测定其P2O5、Fe2O3、Al2O3、SO3含量。方法简便快速,测量线性范围宽,对稀磷酸和浓磷酸均能同时测定,测定结果与化学分析测定结果基本一致。     

波长色散X射线荧光光谱法测定水样中的微量铈

建立了采用波长色散X射线荧光光谱仪测定水样中微量铈的方法。测定结果表明,测量单个样品需100 s,检出限为0.6μg/g。当铈浓度的线性范围为1~1×104μg/g,相对标准偏差不大于1.28%,加标回收率为97.2%~98.6%。该方法快速、准确、环保,不受铈离子价态、水样pH值和共存离子的明显影响。     

波长色散X射线荧光光谱法测定水样中的微量钼

建立了采用波长色散X射线荧光光谱仪测定水样中的微量钼的方法。测定结果表明测量单个样品仅需30 s,检出限为1.6μg/g,相对标准偏差为1.81%,加标回收率为97%~102.9%。方法快速、准确、环保,不受水样pH和共存离子的明显影响。     

基于X射线荧光光谱与双标图对鞋底材料的分类研究

鞋底材料在法庭科学中可作为微量物证出现,利用手持式X射线荧光光谱仪(XRF)检验了30个鞋底样品,获取鞋底材料中无机填料的元素含量信息。使用双标图(Biplot)对样品进行分类,结果可分为5类,表现了各样品在无机元素含量上的差别,并挖掘了各样品在变量上的特征信息;使用层次聚类验证分类结果。结果表明,该方法对鞋底XRF数据分类效果理想;XRF与双标图可以从无机填料角度检验并分类鞋底材料,且双标图方法在分析XRF实验数据中有一定应用潜力。     

X射线荧光光谱法测定推进剂中的金属成分

自行研制了复合推进剂标样,以化学方法测定标样中的Al、Mg含量．建立了工作曲线。同时用XRF法测定推进剂中镁、铝含量。结果表明,Al、Mg含量10次测定的相对标准偏差分别为0．023％和0．061％。样品测试结果与化学方法一致,但更快、更简便,是检测推进剂中金属成分较为理想的方法。     

利用X射线荧光光谱法测定溶剂的主要成分

采用灼烧压片法,对溶剂中CaO、MgO和SiO2三个元素绘制了含量与X射线荧光强度之间的工作曲线,进行了灼烧试验,结果证明该方法完全可替代传统化学法,不仅大大缩短了分析时间,提高了工作效率,而且降低了工作强度。     

X射线荧光光谱法测定磷矿中Na元素的重叠校正

根据钠的X射线荧光光谱扫描图中干扰线ZrLα1，2（2θ=24.60°，2次线），ZnLα1，2（2θ=24．83°，1次线），ZnLβ1（2θ=24°17°，1次线），对NaKα1,2的干扰谱信息，采用数学方法和重叠校正后的系数计算分析元素的强度，此法可降低或消除露叠干扰，提高测量的准确度。     

Some aspects of the analysis of coal by X-ray fluorescence spectroscopy

Bituminous coal samples from 84 distinct sources were analysed by conventional British Standards (BS) methods for phosphorus, sulphur, chlorine, ash and the ash-forming elements (calcium, silicon, aluminium, iron, sodium, magnesium, potassium, titanium and manganese). In most cases four determinations were made per element per source. Samples were crushed to ?212 μm (72 BS mesh) and pressed into aluminium cups at 20 t in^?2 (309 MPa) without binder or backing. Two pellets from each sample were analysed by wave-length dispersive X-ray fluorescence techniques, using a spectrometer equipped with a rhodium rube; the X-ray count took 60 s. The X-ray results were calibrated against the conventional results using multiple regression. The accuracy obtained was comparable with routine ‘wet chemical’ techniques. The X-ray technique is suitable for the routine determination of large numbers of samples.     

铝塑膜包装用热塑性聚氨酯热熔胶的制备与性能研究

以聚酯多元醇、二异氰酸酯和1,4-丁二醇(BDO)为主要原料,合成了铝塑膜包装用热塑性聚氨酯(TPU)热熔胶(HMA),并考察了二异氰酸酯、R值[R=n(—NCO)/n(—OH)]、结晶性多元醇以及扩链剂(BDO)等对TPU-HMA粘接性能的影响。研究结果表明:以4,4′-二苯基甲烷二异氰酸酯(MDI)、聚酯多元醇EVONIK7360为原料,当R=0.99、w(BDO)=2%(相对于聚酯多元醇总质量而言)时,制备的TPU-HMA对铝塑膜具有相对较好的粘接效果,其最终剥离强度为30.0 N/8 mm。     

铝塑复合包装的应用及废弃物回收利用新技术

包装是商品使用、储存、运输的重要保障,不可或缺。塑料包装轻质、易加工、性价比高,增长极快,成为现代社会主要的包装材料,其中铝塑复合包装通过材料优势互补,可满足阻隔性、抗菌性、力学性能和印刷性能等多功能要求,应用广泛,但即用即弃,废弃物难分离难回收利用,无法降解,也难焚烧处理,污染环境,浪费资源,亟待治理。本文综述了铝塑复合包装结构性能和应用,以及废弃物回收利用难点,重点介绍了本团队采用自主创新的固相剪切碾磨加工装备和技术,实现废弃铝塑复合包装的室温超细粉碎和均匀分散,改善加工性和力学性能,制备可拆卸物流包装箱及导热导电功能制品的研究工作。     

Study of polymer gelation by fluorescence spectroscopy

A fluorescence technique is used to study the mechanism and dynamics of thermoreversible gel formation in concentrated polymer solutions. Two examples of these ordered structures were studied: isotactic polystyrene (iPS) in decalin and syndiotactic poly(methyl methacrylate) (sPMMA) in toluene. iPS can form two types of gels in decalin solutions. Turbid suspensions are formed between 60°C and 130°C. When the solution is quenched beneath 20°C, transparent gels are formed. In the former solution the polymer has a 3₁ helix structure; in the latter a 12₁ helix is formed. These structures formed by iPS in decalin solution have different fluorescence spectra. The ratio (I_m/I_e) of the intensity of the monomer fluorescence band in the spectrum over the intensity of the excimer emission band is higher in the spectra of transparent gels. The formation of the transparent gels from a solution can be followed by plotting I_m/I_e as a function of temperature. The kinetics of the gel formation are studied by following I_m/I_e as a function of time at a fixed temperature. sPMMA forms gels in toluene by a mechanism called “conformational gelation.” This mechanism consists of two steps: a fast conformational change followed by a slower aggregation of polymer chains. Both steps were followed by measuring fluorescence of a pyrene label attached to the polymer. The fluorescence lifetime of this probe is sensitive to the polarity of the environment. When the polymer conformation goes from a random coil to an all trans conformation, the environment of the fluorescent label becomes increasingly richer in solvent. This change in polarity is reflected in a change in fluorescence lifetime. The change in fluorescence anisotropy of the label reflects the second step of the mechanism and correlates with the occurrence of chain aggregation.     

腐殖酸与吡虫啉作用的荧光光谱研究

通过对腐殖酸与吡虫啉作用的光谱研究,探讨了吡虫啉与腐殖酸之间的相互作用机理.结果表明,吡虫啉可以有规律的猝灭腐殖酸的荧光,腐殖酸有两类荧光发射峰,吡虫啉对这两类峰的猝灭常数不同;计算了吡虫啉与腐殖酸作用的热力学参数,由第一类结合位置可以推断吡虫啉与腐殖酸分子间主要存在疏水作用力,而由第二类结合位置可以判断吡虫啉与腐殖酸分子也存在一定的静电作用力.通过三维荧光谱图进一步证实这两类峰来自腐殖酸中的不同基团.     

荧光光谱法研究橙皮素与牛血清白蛋白的相互作用

采用荧光光谱技术研究了橙皮素与牛血清白蛋白(BSA)的相互作用.研究发现橙皮素对BSA的荧光猝灭属于静态猝灭过程,由热力学参数焓变△rHm=-60.543 kJ·mol<'-1>,熵变△rSm-114.121J-mol<'-1>均小于零,判断橙皮素与BSA之间主要靠氧键和范德华力相结合,生成自由能变(△rGm)为负值,...     

Study of Ti in solvent-refined coal by X-ray absorption spectroscopy

The chemical environment of titanium in solvent-refined coal (SRC-I and SRC-II) has been studied using X-ray absorption spectroscopy. Evidence that organic complexes of Ti are produced in the liquefaction process from mineral forms of Ti present in the feed coal is presented, based on the pre-edge structure of the X-ray absorption spectra.     

Study of sulphur in Assam coals by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) has been used to study the nature and content of sulphur contained in coal samples from Assam. In each case two sulphur 2p (S 2p) peaks were observed. The 169–171 eV 2p peak corresponds to sulphate, whilst the 164–165 eV peak is assigned to S in iron sulphide compounds such as pyrite, marcasite, etc. and also organic sulphur. The complete absence of a 169–171 eV S peak from a coal sample from which both pyritic and sulphate sulphur were removed by hydrodesulphurization strongly indicates that the remaining 164.7 eV S 2p peak corresponds to the total organic sulphur present in the coal.     

Use of X-ray fluorescence for sorting vinyl from other packaging materials in municipal solid waste

X-ray fluorescence of the chlorine atom is a suitable method for identifying vinyl in a mixed plastics stream in municipal solid waste. The chlorine X-ray is weak and does not penetrate paper labels. There is also a rapid decrease in measured chlorine X-ray intensity as the sample is moved away from the X-ray source and detector which could be a potential problem for bottles of uneven shape.     

基于GA-BP神经网络的塑料X射线吸收光谱的辨识

采集15种塑料样本的X射线吸收光谱(XAS),对光谱数据进行预处理和主成分分析,建立误差反向传播(BP)神经网络和遗传算法优化的误差反向传播(GA-BP)神经网络模型,利用训练集进行网络训练,并通过测试集进行验证。结果表明,GA-BP神经网络相比于BP神经网络可以更好更稳定的对塑料样本的XAS进行识别,这对塑料的回收具有重要的指导意义。