橡胶材料的X射线荧光多元素分析

建立了一种橡胶材料中多元素X射线荧光定量分析的方法。用标准物质对此方法进行检验,相对标准偏差为0．30％－0．58％。该方法用于橡胶样品的测定,相对标准偏差为0．33％－0．62％。     

X射线荧光光谱法测定水样中的痕量元素

采用波长色散X射线荧光光谱仪测定了水样中痕量的A1、Cr、Ni、Zn、Sr、Ba、Tl、Pb。本法的测量结果与ICP和AAS的结果相近，对5．7μg/g Sr测量5次的RSD为1．2％，Sr的检出限(LLD)达到0．1μg/g。     

X射线荧光光谱分析

作为《分析试验室》定期评述“X射线荧光光谱分析”系列评论第八篇,本文收集国内学者在1998年7月至2000年6月期间公开发表在国内外期刊和国际会议文集上的129篇论文,并对此期间对我国X射线荧光光谱分析的概况、发展和国际上的地位进行了讲述,内容包括仪器及维修、基体校正、数据处理方法、谱分析方法的研究、标样及样品制备、全反射X射线荧光光谱、同步辐射光源X射线荧光光谱、粒子激发X射线发射、X射线荧光光谱分析方法研究及其应用。     

牛奶成分可防止放射伤害

日本专家经动物实验确认，牛奶和人类母乳中都含有的成分——乳铁蛋白具有防止放射伤害的功效。来自日本放射医学综合研究所等机构的研究人员将50只实验鼠分成数量相同的两组，只给其中一组的饲料中混入0．1％的乳铁蛋白，并持续一个月。之后，用足以导致半数以上实验鼠死亡的高剂量X射线照射全部50只实验鼠。受X射线照射30天后，未食用乳铁蛋白的实验鼠生存率为62％，而食用含乳铁蛋白饲料的实验鼠生存率达85％。     

X射线荧光分析技术的研发动态

X射线荧光分析法(XRF)的正确命名，根据IUPAC命名委员会的建议，宜称作“X射线发射分析法”，因并不发生荧光，在保护环境的大前提下，它在分析化学中的地位日益受到重视。随着分析仪器向小型化发展的趋势，X射线荧光分析仪也向手提式轻便、小型携化发展，如手枪式或其他便于握持的式样。     

X射线荧光光谱法测定钢中的有害元素

采用X射线荧光光谱法测定钢中有害元素P.S.AS.Pb.Zn.Sn的含量,实现了钢中有害元素P.S.AS.Pb.Zn.Sn含量的在线分析。各待测成分的分析范围为：P0.0042％～0.047％.S0．0094％～0.073％.AS0.011％～0.092％.Pb0.0012％～0．087％.Zn0．0005％～0．011％.Sn0．0093％～0．095％。用该方法对标准样品进行测定。测定结果与标准值基本一致,测定结果的相对标准偏差为1．08％～1．90％(n=10)。     

普通X—射线荧光光谱仪分辨率的改善

作为改善普通Ｘ－射线荧光光谱仪的分辨率和谱线的低能拖尾现象，于ＰＷ１４０４谱仪上加了可拆卸的限制垂直发散准直器（６．５×２０×５０ｍｍ，片间距０．６５ｍｍ）。实验结果表明，加了限制垂直发散准直器后，谱仪相对分辨率提高１０％，谱仪非对称因子由１．４－１．５改善为１．０－１．１８。为普通Ｘ－射线谱仪用于化学态分析提供了更为有利的条件。     

X射线荧光光谱法测定萤石中的氟,钙及二氧化硅

提出艇偏硼酸锂和四硼酸锂混合熔剂熔融制样，以Ｘ－射线荧光光谱法定量测定萤石中ＣａＦ２、总钙和二氧化硅。经实际试样和标准试样检测，本法可用实际试样分析，在ＣａＦ２含量为７７－９８％时，其最大误差为０．６０％。     

聚酰亚胺模塑粉形态结构的 X射线分析

应用广角X射线衍射技术和小角X射线散射技术，对不同热处理温度下的聚酰亚胺模塑粉的形态结构进行了研究。结果表明：随着热处理温度的不同，模塑粉的结晶形态也相应发生变化。其中，热处理温度380℃与室温25℃相比较，模塑粉的相对结晶度增加近一倍；微观粒径尺寸也增加20％以上。     

波长色散X射线荧光光谱法测定纯金中金

应用波长色散X射线荧光光谱法(WDXRF)对纯金(金含量为98．00％～99．95％)中金含量进行定量分析。利用国家标准物质和自行研制的工作标样建立校准曲线，采用Lachance-Trill浓度校正模式消除吸收-增强效应；进行背景修正以提高测低浓度组分的准确度。对样品的测试结果与其它方法结果比较，证明此法可行。金含量在98．00％～99．95％范围内，分析结果与其他方法结果的偏差绝对值均小于0．10％。     

Studies on the Electrochemical Characteristics of K2FeO4 Electrode

Discharge performance of K2FeO4 electrode under different conditions was studied by the constant electric current discharge method. The electrochemical characteristics of K2FeO4 electrode were investigated for the first time by means of cyclic voltammetry. The results show that the K2FeO4 electrode made at moderate pressure (20MPa) and discharged at lower current has better discharge performance. It is also found that K2FeO4 electrode is significantly rechargeable.     

FeO(OH)-TiO2/CoPi复合光阳极的制备及其光电催化氧化水性能

采用溶胶-凝胶法制备了TiO₂ 纳米晶, 并通过浸渍技术在其表面引入了FeO(OH). 采用紫外-可见(UV-Vis)吸收光谱确定了引入FeO(OH)的最佳Fe³⁺浓度. 通过电化学法在FeO(OH)-TiO₂光阳极上沉积了催化水分解制备氧气的钴基催化剂(CoPi), 得到了FeO(OH)-TiO₂/CoPi 复合光阳极. 利用透射电镜(TEM), 高分辨透射电镜(HRTEM), X射线衍射(XRD), 扫描电镜(SEM)对TiO₂纳米晶, FeO(OH)-TiO₂以及FeO(OH)-TiO₂/CoPi复合光阳极进行了表征, 采用电化学和光电化学技术研究了中性条件下FeO(OH)-TiO₂/CoPi 复合光阳极的光电催化分解水性能. 结果表明, TiO₂纳米晶为梭形的锐钛矿, 其表面修饰的FeO(OH)为针铁矿型, 且当前驱体溶液中Fe³⁺与TiO₂的质量比为0.05%时得到的FeO(OH)-TiO₂具有最佳的光吸收效果. 形成FeO(OH)-TiO₂/CoPi复合光阳极后, 在光照条件下CoPi 电催化分解水制备氧气的过电位显著降低. TiO₂表面FeO(OH)的引入增加了光阳极对可见光的吸收能力, 同时光阳极表面沉积的CoPi有效地利用了FeO(OH)-TiO₂产生的光生空穴, 将水氧化形成氧气, 从而在光照条件下显著提高了CoPi催化氧化水的效率.     

高铁酸钾氧化脱除模拟轻质油中的含硫化合物

考察了K2FeO4对模拟轻质油中苯并噻吩（BT）及二苯并噻吩（DBT）的氧化性能。结果表明,水相中K2FeO4对BT、DBT的氧化活性比较低,水的存在使K2FeO4水解成黄色的Fe(OH)3而失去氧化有机硫化物的能力;在冰乙酸反应介质中,K2FeO4对BT及DBT的氧化活性有了明显的提高;固体催化剂KM的加入显著提高了乙酸反应介质中K2FeO4对BT及DBT的氧化活性。常温、常压,醋酸/模拟油体积比为1.0,K2FeO4/S摩尔比为1.0,KM/K2FeO4质量比为1.0的条件下,DBT的转化率达98.4%,BT的转化率为70.1%。     

高铁酸钾的合成与电化学性能研究

本文主要研究了锂离子电池正极材料高铁酸钾的合成,表征和电化学性质.用次氯酸钾与硝酸铁于碱性介质中反应得到高铁酸钾粗品,重结晶后成纯度大于97%的产品,用XRD和FTIR等方法对高铁酸钾进行表征和分析.初步研究了K2FeO4/Li电池的充放电性能.     

High rate capability of Fe/FeO/Fe3O4 composite as anode material for lithium-ion batteries

Fe/FeO/Fe₃O₄ composite was synthesized by a simple solid method using ferric citrate and phenolic resin as raw materials. The reaction processes of raw materials mixture were characterized by thermogravimetric analysis (TGA) under nitrogen. X-Ray diffraction (XRD) and scanning electron microscopy (SEM) were used to investigate the structure and morphology of the products. The results showed that the obtained material was octahedral Fe/FeO/Fe₃O₄ composite with a size of 2-4 μm. The electrochemical performances of Fe/FeO/Fe₃O₄ composite as anode material were also evaluated, which exhibited a stable specific capacity of 260.3 mAh g^-1 and an ideal initial coulombic efficiency of 90.8% in the range of 0.05~3 V at the 5C rate. A good rate capacity of Fe/FeO/Fe₃O₄ composite electrode was also shown by the charge-discharge testing even at the rate of 60C. The better rate capability of Fe/FeO/Fe₃O₄ electrode could be measured in higher temperature.     

La0.5>RE0.3Sr0.2FeO3－δ (RE = Nd、Ce、Sm)体系双稀土阴极材料的制备与电性能

采用甘氨酸-硝酸盐法(GNP)合成了La0.5RE0.3Sr0.2FeO3－δ(RE=Nd、Ce、Sm)系列复合氧化物粉体. 用X射线衍射(XRD)和TG-DSC分析了样品钙钛矿物相的形成过程, 用Archimedes排水法测量体积密度并计算烧结样品的相对密度, 用四端子技术测量电导率. 结果显示, 掺Nd的样品1200 ℃烧结2 h成为单一立方钙钛矿结构, 掺Ce样品有明显的CeO2立方相析出, 掺Sm样品主相为钙钛矿结构伴有微弱的杂峰. 1250 ℃烧结2 h的La0.5Nd0.3Sr0.2FeO3－δ在600 ℃时电导率高达100 S•cm-1以上, 明显高于La0.5Ce0.3Sr0.2FeO3－δ及La0.5Sm0.3Sr0.2FeO3－δ样品的电导率, 预示着La0.5Nd0.3Sr0.2FeO3－δ可能是一种良好的中温固体氧化物燃料电池(SOFC)阴极材料.     

Characterization,Antiplasmodial and Cytotoxic Activities of Green Synthesized Iron Oxide Nanoparticles Using Nephrolepis exaltata Aqueous Extract

The use of non-toxic synthesis of iron oxide nanoparticles (FeO NPs) by an aqueous plant extract has proven to be a viable and environmentally friendly method. Therefore, the present investigation is based on the FeO NPs synthesis by means of FeCl₃·6H₂O as a precursor, and the plant extract of Nephrolepis exaltata (N. exaltata) serves as a capping and reducing agent. Various techniques were used to examine the synthesized FeO NPs, such as UV-Visible Spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX). The FT-IR studies were used to identify different photoactive biomolecules at 3285, 2928, 1415, 1170, and 600 cm⁻¹ in the wavenumber range from 4000 to 400 cm⁻¹, indicating the -OH, C-H, C-O, C-C, and M-O groups, respectively. The XRD examination exhibited crystallinity, and the average diameter of the particle was 16 nm. The spherical nature of synthesized FeO NPs was recognized by SEM images, while the elemental composition of nanoparticles was identified by an EDX spectrophotometer. The antiplasmodial activity of synthesized FeO NPs was investigated against Plasmodium parasites. The antiplasmodial property of FeO NPs was evaluated by means of parasite inhibitory concentration, which showed higher efficiency (62 ± 1.3 at 25 μg/mL) against Plasmodium parasite if compared to plant extracts and precursor. The cytotoxicity of FeO NPs was also assessed in human peripheral blood mononuclear cells (PBMCs) under in vitro conditions. The lack of toxic effects through FeO NPs keeps them more effective for use in pharmaceutical and medical applications.     

高铁酸钾的合成及其性能

高铁酸钾最初是作为选择性氧化剂或非氯型高效水处理剂使用。1999年lieht提出高铁酸钾作为电池的正极活性物质,对于高铁酸盐的认识达到一个新的高度。     

Experimental and theoretical study of the reactions between small neutral iron oxide clusters and carbon monoxide

Reactions of small neutral iron oxide clusters (FeO(1-3) and Fe(2)O(4,5)) with carbon monoxide (CO) are investigated by experiments and first-principle calculations. The iron oxide clusters are generated by reaction of laser-ablation-generated iron plasma with O(2) in a supersonic expansion and are reacted with carbon monoxide in a fast flow reactor. Detection of the neutral clusters is through ionization with vacuum UV laser (118 nm) radiation and time-of-flight mass spectrometry. The FeO(2) and FeO(3) neutral clusters are reactive toward CO, whereas Fe(2)O(4), Fe(2)O(5), and possibly FeO are not reactive. A higher reactivity for FeO(2) [sigma(FeO(2) + CO) > 3 x 10(-17) cm(2)] than for FeO(3) [sigma(FeO(3) + CO) approximately 1 x 10(-17) cm(2)] is observed. Density functional theory (DFT) calculations are carried out to interpret the experimental observations and to generate the reaction mechanisms. The reaction pathways with negative or very small overall barriers are identified for CO oxidation by FeO(2) and FeO(3). The lower reactivity of FeO(3) with respect to FeO(2) may be related to a spin inversion process present in the reaction of FeO(3) with CO. Significant reaction barriers are calculated for the reactions of FeO and Fe(2)O(4-5) with CO. The DFT results are in good agreement with experimental observations. Molecular-level reaction mechanisms for CO oxidation by O(2), facilitated by condensed phase iron oxides as catalysts, are suggested.     

Micro-fusion and spectrophotometric determination of iron(II) and iron(III) in chrome spinels and other refractories

Spectrophotometric determination of FeO in milligram samples of chrome spinels and related refractory minerals after high-frequency micro-fusion with lithium tetraborate in an inert atmosphere is described. Anomalous responses (apparent reduction or oxidation of FeO depending on the ferroïn-type reagent)_rendered the procedure highly unreliable. All the fluxes containing structural oxygen, as well as phosphoric acid, acted as oxidants even when atmospheric oxidation was rigorously excluded. However, the method is suitable for micro-determination of total iron in spinels. Spectrophotometric measurements gave an average relative standard deviation of 0.73%.