基于锁相放大器的微扰型共面波导铁磁共振测试参量研究

铁磁共振测试是自旋电子学研究的重要手段，为实现简单高效的FMR测试，基于瑞士苏黎世仪器500k MFLI锁相放大器，搭建了微扰型宽频带共面波导式铁磁共振测试系统，并对坡莫合金等材料进行了测试.为了得到材料的真实性质，对影响实验结果的参量进行优化，在深入讨论了这些参量对实验结果的影响及其物理和数学机制后，得到准确铁磁共振测试结果的实验条件为：电磁铁定点增加模式下，锁相放大器的时间常量为100 ms,滤波阶数在2阶以上，微扰线圈驱动信号振幅为1～2 V,频率为33～200 Hz.     

基于激光诱导击穿光谱技术检测分析原铝中硅、铁元素含量

利用自行搭建的LIBS装置对原铝中硅铁含量进行了分析测试，测试前对原铝试样进行了微观形貌分析，研究发现原铝中硅元素除有个别区域聚团现象外，其分布相对较为均匀；铁元素多以团状汇聚形态出现，且无明显的分布规律。实验分别考察了激光脉冲能量对激光诱导原铝等离子体光谱的影响，发现随着激光脉冲能量的增大，硅、铁元素信噪比先增加后减小，硅、铁谱线信噪比最大值均出现在160 mJ处，实验选取的激光脉冲能量为160 mJ。在上述较为合理的实验条件下，以内标法为基础，分别采用两种标样（纯铝标样与自选标样）建立了定标模型；结果表明：相比于纯铝标准试样，采用自选试样建立的定标模型不够理想，且数据的离散程度较大，铁元素直线拟合优度仅为0.921 3，相对标准偏差也较大。采用纯铝标样时，在试样不旋转的情况下，硅、铁元素定标曲线拟合优度分别为0.961 1与0.974 1，相对标准偏差分别为8.85%与9.43%，且误差棒显示误差随定标试样的硅、铁含量升高而增大。当试样台保持转速50 r·min-1条件下进行实验，发现硅、铁元素定标曲线的拟合优度分别为0.978 5与0.988，相对标准偏差分别为3.78%与3.4%，相比于试样平台固定情况下的定标结果，拟合优度明显改善，相对标准偏差也有所降低，定标模型明显优于自选试样建立的模型。使用两种定标模型对25个测试样进行了分析测试，比较了两种测试结果的相对误差，纯铝定标试样由于含量梯度较大，跨度较宽，采用该标样建立的定标模型对低铁原铝试样测试适应性相对较差，而自选试样建立的定标模型虽然不够理想，但针对低铁原铝试样的测试适应性相对较好。对激光诱导原铝产生的等离子体进行了诊断，通过镁元素几条离子谱线的玻耳兹曼图，计算出了等离子体温度约为9 163.63 K，利用镁元素一条谱线的Stark展宽估算出等离子体电子密度为1.69×1017 cm-3，验证了激光诱导原铝等离子体处于局部热力学平衡状态的假设是成立的。     

铁原子团簇的红外与微波吸收性能

以文献［１］中提出的金属原子团簇的电子能谱和吸收光谱理论为指导，对铁原子团簇的红外与微波吸收性能进行了实验测定。实验结果证明这个理论是正确的。测试结果表明：纳米级铁原子团簇材料具有很强的红外吸收性能，微米级铁原子团簇材料具有很强的微波吸收性能，与文献［３］中的理论相符。     

ICP-AES法快速测定球团铁矿中的总铁、二氧化硅、氧化钙、氧化镁及三氧化二铝

应用ICP-AES法快速测定球团铁矿中的总铁、二氧化硅、氧化钙、氧化镁及三氧化二铝的含量。对测试仪器条件及元素谱线等相关参数进行实验和优化，对3种样品前处理方法所能达到的测试目标进行实验对比，对基体干扰及方法的准确度和精密度进行研究，并用标准物质验证。     

基于MATLAB的合肥光源储存环束流轨道校正系统

 闭轨畸变对合肥同步光源的束流质量产生负面影响，因此必须对闭轨畸变进行校正。本文介绍了基于MATLAB的合肥光源储存环束流轨道校正系统的工作原理、开发过程及测试结果。该系统由束流轨道测量系统、校正铁系统和控制系统组成，基于MATLAB开发的束流轨道校正程序运行于操作员界面工作站上。首先对获取的束流轨道数据进行分析和计算，然后通过控制系统改变校正铁电源的电流以改变校正铁磁场强度，从而实现轨道校正。测试结果表明：束流轨道的最大畸变由校正前的4.468 mm下降到校正后的0.299 mm；标准方差（SDEV）由校正前的2.986 mm下降到校正后的0.087 mm。该系统达到了设计目标。     

Effect of Cyclic Deformation on Magnetorheological Elastomers

采制备了铁颗粒含量分别是60%,70%和80%的三种材料,在应变幅值为50%,75%和100%的循环加载条件下,利用改进后的动态力学分析仪测试了循环加载后材料的储能模量和损耗模量. 结果显示铁颗粒含量为70%和80%的样品,其储能模量和损耗模量都和循环加载的幅值以及循环加载的次数有关,铁颗粒含量为80%样品受加载条件的影响尤其明显. 但铁颗粒含量为60%的样品,其性能却与循环加载的幅值和次数无关. 为了更好的研究磁流变弹性体受循环加载后的性能,样品还进行了准静态拉伸测试,并用扫描电镜对测试的样品进行了原位观察.     

多普勒效应测试仪的改进

为了解决电磁波多普勒效应在实验室演示的困难，采用单片机和一系列大规模集成电路设计了一种演示电磁波多普勒效应的测试仪器，分析了电磁波的多普勒效应原理，给出了该仪器的组成结构，介绍了该仪器铁特点。     

ICP－AES法同时测定聚酯切片中的钛和铁

本文介绍ＩＣＰ－ＡＥＳ法同时测定聚酯切片中钛和铁的方法。试样以干法分解，以硫酸，硫酸铵溶解残渣后进行测试。回收率为９３．５％－１００．６％，ＲＳＤ＜３．８３％     

钾掺杂三(二苯甲酰甲基)铁的超顺磁性

本研究通过高真空退火法制备了钾掺杂三(二苯甲酰甲基)铁分子晶体的粉末样品.X-射线衍射测试结果表明,合成样品与纯三(二苯甲酰甲基)铁的晶体结构明显不同,平均晶粒尺寸约为20.5 nm.直流磁化率和交流磁化率的测试结果表明,合成的样品具有阻塞温度(TB)约为8.0 K的超顺磁性,这与纯有机物在1.8—300 K整个测试温...     

电沉积铁层晶体结构变化的第一性原理计算

研究了以氯化亚铁为主盐的电镀铁工艺,通过扫描电子显微镜微观形貌分析,铁镀层具有均匀致密结构,铁晶体具有较小的尺寸。通过X射线衍射测试发现,铝基底对铁镀层具有明显的诱导作用,然而随着沉积时间的增加,铁镀层逐渐趋向于Fe（211）晶面择优取向。采用第一性原理计算了不同晶面的表面能,铁晶体不同晶面的表面能依次为Fe（211）＜ Fe（110）＜Fe（200）,这很好地解释了Fe（211）晶面择优取向使体系的整体能量降低,有益于铁镀层的稳定性。     

缅甸翡翠中铁元素的激光诱导击穿光谱定量检测

采用激光诱导击穿光谱(LIBS)技术定量分析缅甸翡翠中Fe元素的浓度。选择Fe元素的275.57 nm光谱线作为定量分析谱线,选取Si元素的288.17 nm光谱线作为内标谱线,选取12个缅甸翡翠样品作为研究对象,以其中9个样品绘制了传统定标法和内定标法的Fe元素定标曲线,并将定标曲线用于3个检验样品的Fe含量的实际预测。实验结果表明,采用传统定标方法时,定标样品光谱强度的相对标准偏差(RSD)在1.4%～8.3%之间,所建立的Fe元素浓度含量定标曲线的拟合相关系数R2为0.979,使用该方法建立的定标曲线对3个检验样品中Fe元素含量进行测定,最大相对误差为10.6%;而采用内定标法时,定标样品光谱强度的比值(I_Fe/I_Si)的相对标准偏差(RSD)在0.9%～5.7%之间,Fe的拟合相关系数R2达到0.989,样品中Fe元素的测定相对误差均可降低到7%以下。结果证明,利用内定标法定量分析翡翠中Fe的含量比传统定标法相对误差更小,采用LIBS技术结合内定标法更适于缅甸翡翠样品中Fe元素定量分析。     

基于反射光谱的土壤铁元素含量估算

近几十年来,光谱技术在土壤科学中的应用越来越受到重视。利用土壤反射光谱可以快速获取土壤信息,了解土壤理化属性,对土壤铁含量进行估算。在已有的研究中,土壤铁的光谱估算多选用表层土壤,大多进行全铁的估算,忽略了不同形态的土壤铁,且估算结果并不十分理想。为了得到不同形态土壤铁最佳模型的处理方法,并探讨有机质含量和土壤深度对不同形态土壤铁估算精度的影响,以江苏省东台市为研究区,选取20个地点共采集了160份土壤样品,将每份样品分别研磨至10目和100目,在室内进行光谱数据采集之后,在使用八种不同方法进行预处理的同时将每种方法都选取多种参数,利用偏最小二乘回归法将全反射波段分别与土壤中的全铁、游离铁、无定形铁的含量进行建模回归,并评价模型精度。结果表明：(1)建立三种不同形态土壤铁的最优模型的处理方式都是将土壤研磨成100目,采用多元散射矫正法,全铁的决定系数(R2)只有0.6,而且模型不够稳定;游离铁和无定形铁估算结果比较好,R2分别达到了0.77和0.69,而且误差小,模型稳定;(2)由于全铁中的硅酸铁很容易受到外界环境的影响,有机质和土壤深度对全铁的估算精度影响都很大,对游离铁的估算精度影响最小;无定形铁由于含量少,其估算模型也比较容易受到有机质和土壤深度的影响。     

Starch vermicelli template for synthesis of magnetic iron oxide nanoclusters

A novel method for fabricating magnetic iron oxide nanoparticles was achieved by using transparent vermicelli template as a new stabilizing material. The morphology of the as-prepared magnetic iron oxide deposited on the surface of vermicelli was observed as nanoclusters. The magnetization of the magnetic iron oxide nanoparticles at room temperature was decreased after carbonization at 200 °C. Therefore the thermal decomposition of iron oxide nanoparticles stabilized by starch vermicelli template yielded iron oxide/carbon nanocomposites with the soft magnetic behavior which are useful for biomedical applications.     

The detection of HBV DNA with gold-coated iron oxide nanoparticle gene probes

Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10) and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic separator was feasible and might be an alternative effective method.     

Reversible dilation of hydrogen charged zone melted iron at 25 °C

The deflection method was used for hydrogen diffusion measurement with high purity zone melted (ZM) iron and with other kinds of less pure iron samples. The results confirmed the conclusion that there is a qualitative difference between ZM iron and less pure iron samples concerning the irreversible effects due to hydrogen. The behaviour of ZM iron was studied by the deflection method for different charging conditions and it was found that the results corresponded to those obtained by the permeation method.     

PAR-吖啶黄能量转移荧光猝灭法测定痕量铁(Ⅱ)的研究

对 4 (2 吡啶偶氮 ) 间苯二酚 (PAR)与吖啶黄间荧光能量转移进行了探讨 ,研究了其能量转移的最佳条件 ,并应用该体系测定痕量铁 (Ⅱ ) ,由此建立了能量转移荧光测定痕量铁的新方法。在λex/em =46 5nm/5 0 5nm ,十二烷基硫酸钠 (SDS)作用下 ,pH =9 2时 ,吖啶黄与PAR 铁 (Ⅱ )络合物间能发生有效能量转移 ,使吖啶黄的荧光猝灭。铁的量在 0～ 10 μg·L-1范围内呈良好的线性关系。最低检出限 0 0 6 μg·L-1。该方法用于水样、发样中痕量铁的测定 ,结果满意。     

多波长线性回归分光光度法同时测定油中的铁、钴、镍

本文提出一种同时测定铁,钴,镍的新方法,即多波长线性回归分光光度法,利用铁与５－Ｂｒ－ＰＡＤＡＰ形成的络合物在７５０ｎｍ处吸收峰不受钴,镍干扰的特点,在７５０ｎｍ处于工作曲线法测定铁的含量,对于钴,镍在５５０－６００ｎｍ内采用多波长线性回归法测定。应用于合成样及油样中铁,钴,镍含量的测定,结果令人满意,回收率为９５．７％￣１０４．３％,相对标准偏差为１．４％￣３．８％。     

Iron oxide thin film growth on Al2O3/NiAl(1 1 0)

The electronic structure and the growth morphology of iron oxide thin films were studied by means of Synchrotron Radiation Photoelectron Spectroscopy (SRPES) and Low Energy Electron Diffraction (LEED). A thin well-ordered alumina film on a NiAl(1 1 0) single crystal surface as a template for iron oxide growth was employed. Two different methods of iron oxide film preparation were applied. In the first attempt, iron deposited at room temperature was subsequently annealed in oxygen. Even though a whole layer of iron was oxidized, an expected long-range order was not achieved. The second attempt was to perform reactive deposition. For this reason iron was evaporated in oxygen ambient at elevated substrate temperature. This method turned out to be more efficient. Diffused but clear LEED patterns of six-fold symmetry indicating hexagonal surface atoms arrangement were observed. From the PES measurements, binding energies for Fe2p for grown iron oxide film were established as well as energy distribution curves for the valence band. Growth curves based on Fe3p core-level peak intensities for iron and iron oxide were plotted identifying type of film growth for both deposition methods. Based upon these results we have found evidence for interdiffusion in the interface between alumina and iron oxide at the early stages of growth. Further deposition led to formation of Fe₃O₄(1 1 1) (magnetite) overlayer. Moreover, the quality of the film could also be improved by long-time annealing at temperatures not exceeding 575 K. Higher annealing temperature caused disappearance of LEED pattern indicating loss of long-range ordering.     

Mössbauer characterisation of Fe–polygalacturonate as a medicine for human anaemia: the effect of iron concentration

⁵⁷Fe Mössbauer spectroscopy was used to study the effect of iron concentration on the oxidation state and microenvironments of iron in Fe–polygalacturonate compounds prepared by a novel method from pectin. The iron concentration of the coordination compounds was determined by inductively coupled plasma optical emission spectrometry analysis. The Mössbauer spectra of the studied compounds could be decomposed into three markedly different quadrupole doublets referring to three microenvironments. Two of these have ferrous and one has ferric oxidation state. In the applied concentration range the relative occurrence of the ferric component was found to increase considerably with iron concentration. At the same time, with increasing iron concentration the relative occurrence characteristic of the three components showed saturation behaviour up to the iron concentration at which for each pair of galacturonic acid units there is on average one iron atom in the system, which iron concentration value is interpreted as to be related to the complete fill up of certain iron complexation sites of the polygalacturonate chains.     

Quantitative elemental analysis of Fe?Zn‐alloy coating by nondestructive method

A quantitative analytical method of iron content in Fe? Zn‐alloy coating by x‐ray diffraction (XRD) spectrum was proposed. This work aimed to replace the wet chemical analysis of Fe? Zn‐alloy coating with rapid and reproducible quantification by an XRD spectrum. Partial least‐squares (PLS) model was utilized to differentiate the spectral characteristic as well as to quantify each component in XRD spectrum. Fifteen standard samples were prepared by heat treatment and verified by the relationship between wet chemical analyses and the XRD spectrum for iron content. The suggested method showed satisfactory precision and accuracy in the analysis of Fe? Zn‐alloy coating. The accuracy for iron content in Fe? Zn‐alloy coating was 0.17 wt%. Copyright © 2008 John Wiley & Sons, Ltd.