110keV56Fe^1^＋离子注入麦胚中的能量沉积分布

测量１１０ＫＥｖ５６Ｆｅ＾１＾＋离子注入麦胚中的射程为２５７．１ｎｍ。根据测得的＾５＾６Ｆｅ＾１＾＋离子相对浓度随深度的分布和注入离子的总面密度，求得了＾５＾６Ｆｅ＾１＾＋离子绝对浓度随深度的分布。采用ＴＲＩＭ８８程序计算得到了不同浓度上注入离子的阻止本领，从而求得了随深度的能量沉积分布。并讨论了细胞损伤的可能机理。     

用蒙特卡洛方法研究大气簇射契伦柯夫光与初级宇宙线特性之间的关系

对γ，ｐ和Ｆｅ所产生的宇宙线大气族射契仑契夫光的强度分布特性进行了计算机模拟。结果表明，在初级宇宙线的能量处于能谱的“膝”区附近时，Ｆｅ族射产生的契仑柯夫光强分布的变化率总是比γ和ｐ簇射的要小。     

Zr（Fe,Cr）2金属间化合物在500℃过热蒸汽中的腐蚀研究

用非自耗电弧炉熔炼了Ｆｅ／Ｃｒ比值为１．７５和４．５０的Ｚｒ（Ｆｅ，Ｃｒ）２金属间化合物．它们的粉末经５００℃、１０．３ＭＰａ过热蒸汽腐蚀不同时间后，用Ｘ射线衍射、电子探针和透射电子显微镜分析了腐蚀后生成物的结构及其形貌，以及成分的重新分布．Ｆｅ／Ｃｒ比值不同的Ｚｒ（Ｆｅ，Ｃｒ）２腐蚀后的生成物都相同，但是含Ｃｒ高的更不易被腐蚀．腐蚀初期的生成物是立方ＺｒＯ２，并析出αＦｅ（Ｃｒ）．继续腐蚀时立方ＺｒＯ２逐渐转变为单斜ＺｒＯ２，αＦｅ（Ｃｒ）也逐渐被氧化成（Ｆｅ，Ｃｒ）３Ｏ４．Ｆｅ和Ｃｒ在偏聚时，Ｆｅ原子的扩散速率比Ｃｒ原子快．根据本实验结果，讨论了第二相影响Ｚｒ４合金腐蚀性能的原因     

非晶态Fe—（Co,Cr）—Zr合金的磁矩分布和电子结构的穆斯堡尔谱研究

分析了室温、７７Ｋ及外加磁场下淬火态和室温下掺氢非晶态Ｆｅ９０－ｘＣｏｘＺｒ１０（ｘ＝４，１０，２０，３０，４０）和Ｆｅ９０－ｙＣｒｙＺｒ１０（ｙ＝０，４，７，１３，１６）的穆斯堡尔谱和超精细场分布Ｐ（Ｈｈｆ）－Ｈｈｆ。实验结果表明：（１）Ｆｅ９０－ｘＣｏｘＺｒ１０（ｘ＝３０，４０）的Ｐ（Ｈｈｆ）是单峰的，表现为强的铁磁性；崦Ｆｅ９０－ｘＣｏｘＺｒ１０（ｘ＝４，１０，２０）和Ｆｅ９０－ｙＣｒｙＺｒ     

YFe10Mo2的粉末中子衍射研究

在中子三轴谱仪上用粉末中子衍射测定室温下ＹＦｅ１０Ｍｏ２的晶体结构和磁结构，衍射数据用ＦＵＬＬＰＲＯＦ轮廓精修程序进行处理，确定替代原子Ｍｏ的占位、占位数以及磁性原子Ｆｅ的原子磁矩的大小和方向。ＹＦｅ１０Ｍｏ２显铁磁性，为单轴各向异性。     

用微合金化和宏合金化改变Ni3Al合金的晶界结构

测量了二元多晶Ｎｉ３Ａｌ．含Ｂ．含Ｚｒ、Ｆｅ和含Ｈｆ、Ｆｅ的Ｎｉ３Ａｌ合金的ｅ＋寿命谱。在Ｎｉ３Ａｌ合金中加入Ｂ，Ｂ原子强烈地偏聚到Ｎｉ３Ａｌ合金的晶界上．使该处的价电子浓度与基体中的相近。含Ｚｒ、Ｆｅ和含Ｈｆ、Ｆｅ的Ｎｉ３Ａｌ合金的τ２都比二元Ｎｉ３Ａｌ的小．且以含Ｚｒ、Ｆｅ的τ２最小．表明在Ｎｉ３Ａｌ合金中加入Ｚｒ、Ｆｅ（或Ｈｆ，Ｆｅ）可增加合金中的金属键成分．使晶界处参与形成金属键的自由电子浓度增加，改善了晶界结构。     

中子衍射研究Ho2Fe9Ga2Al6和Ho2Fe9Ga6Al2的晶体结构与磁结构

在中子三轴谱仪上用粉末中子衍射测定室温下Ｈｏ２Ｆｅ９Ｇａ２Ａｌ６和Ｈｏ２Ｆｅ９Ｇａ６Ａｌ２的晶体结构和磁结构，衍射数据用Ｉｚｕｍｉ的Ｒｉｅｔｖｅｌｄ分析程序ＲＩＥＴＡＮ进行轮廓精修处理，确定替代原子Ｇａ、Ａｌ的占位及占位数以及磁性原子Ｈｏ、Ｆｅ的原子磁矩的大小和方向，Ｈｏ２Ｆｅ９Ｇａ２Ａｌ６显顺磁性，Ｈｏ２Ｆｅ９Ｇａ６Ａｌ２显亚铁磁性，显单轴各向异性，并给出了居里温度和饱和磁化强度随Ｇａ、Ａｌ含量     

中子衍射研究Ho_2Fe_9Ga_2Al_6和Ho_2Fe_9Ga_6Al_2的

在中子三轴谱仪上用粉末中子衍射测定室温下Ｈｏ２Ｆｅ９Ｇａ２Ａｌ６和Ｈｏ２Ｆｅ９Ｇａ６Ａｌ２的晶体结构和磁结构，衍射数据用Ｉｚｕｍｉ的Ｒｉｅｔｖｅｌｄ分析程序ＲＩＥＴＡＮ进行轮廓精修处理，确定替代原子Ｇａ、Ａｌ的占位及占位数以及磁性原子Ｈｏ、Ｆｅ的原子磁矩的大小和方向。Ｈｏ２Ｆｅ９Ｇａ２Ａｌ６显顺磁性，Ｈｏ２Ｆｅ９Ｇａ６Ａｌ２显亚铁磁性，显单轴各向异性。并给出了居里温度和饱和磁化强度随Ｇａ、Ａｌ含量的变化关系。     

铁掺杂Y－124高温超导相的电场梯度研究

将点电荷模型和有效价键理论结合起来，发展成点电荷－有效键价模型理论。并利用这种理论模型研究了在高Ｔｃ氧化物超导体Ｙ—１２４结构中被铁杂质原子所占据的有不同局域环境的铜晶位上的电场梯度和所对应的四极劈裂．利用这种方法建立了Ｆｅ（３＋）离子在亚晶格尺度上的位移与其电场梯度和周围各离子有效化合价的关系．根据实验中的四极劈裂观察值，从理论计算结果中得到对应于Ｆｅ－Ｏ五配位的Ｆｅ（Ｂ’）离子将偏离ＣｕＯ２面０．０１９５ｎｍ，而具有Ｆｅ－Ｏ六配位的Ｆｅ（Ｂ）离子将偏离０．０３９５ｎｍ．此两晶位上的电场梯度分别沿着＋Ｚ和－Ｚ方向。这种点电荷－有效键价模型对高Ｔｃ氧化物超导体实验中晶位的指认和Ｆｅ（３＋）的位移分析有重要的意义。     

Fe^3＋—Vc体系的穆斯堡尔研究

用穆斯堡尔方法研究了Ｆｅ＾３＋－Ｖｃ体系中铁离子的价态及冻干粉末中Ｆｅ＾２＋与大颗粒晶体中Ｆｅ＾２＋的差别。结果表明：Ｆｅ＾３＋－Ｖｃ溶液结晶后，大颗粒晶体中还原得到的Ｆｅ＾２＋未被空气氧化，但Ｆｅ＾２＋有２种配位环境，数量比为２：３；冻干粉末中Ｆｅ＾２＋绝大部分未变成Ｆｅ＾３＋，自然升温冻干的粉末中以其中一种配位环境为主，而控温冻干测以另一种配位环境为主。     

Evolution of nanoscopic iron clusters in irradiated zirconium alloys with different iron contents

We investigate the distribution of alloying elements in irradiated Zr alloys with different Fe contents using atom probe tomography. Our results showed dense nanoscale regions (clusters) of Fe formed in the matrix. The average diameter of the Fe clusters in alloy with a high Fe content increased under a higher neutron fluence. Conversely, the number density of Fe clusters remained similar in all the Zr alloy specimens. Energy-dispersive X-ray spectrometry showed that the maximum cluster size depended on the Fe content in the secondary phase particles. Fe clusters gathered along the basal plane of the Zr alloys at high fluence, indicating that irradiation defects influence Fe clustering. The solute concentration of Fe was estimated to be approximately 0.1 at%, which is the Fe concentration in the matrix exclusive of Fe clusters.     

STUDY ON Fe ION DISTRIBUTION IN NATURAL CHROMITE BY MOSSBAUER TECHNIQUE

Mossbauer absorption spectra in a natural chromite from Shanxi province of China were measured, covering a temperature range from 12 K to 800 K. Each spectrum at low temperature can be fitted to three doublets: the first two are attributed to tetrahedral T-site Fe ions and the third one to octahedral M-site Fe ions. Such assignment was confirmed by the detailed analyses of the temperature dependent centre shift and other parameters. As a main result, our data strongly supported the ordered distribution with Fe2+ in T-site and Fe3+ in M-site for chromite studied. No evidence for electron hopping processes was detected.     

用蒙特卡洛方法研究大气簇射契仑柯夫光与初级宇宙线特性之间的关系

对γ，p和Fe所产生的宇宙线大气簇射契仑柯夫光的强度分布特性进行了计算机模拟。结果表明，在初级宇宙线的能量处于能谱的“膝”区附近时，Fe簇射产生的契仑柯夫光强分布的变化率总是比γ和p簇射的要小。同时还发现，存在一个到簇射中心的特殊距离，在这里3种初级宇宙线所产生的契仑柯夫光的强度相同。这些特点可以被用来估计初级宇宙线的能量或区分初级宇宙线中的轻粒子和重粒子。     

同步辐射X射线小角散射法研究纳米铁材料在生物介质中的粒度分布

在研究纳米材料的生物效应时,首先需要对纳米材料在生物介质中的物理化学性质进行全面详细的表征.受生物介质中高蛋白浓度和高离子强度的影响,纳米颗粒在生物介质中极易团聚,对纳米颗粒在生物分散体系中的粒度表征十分困难.本实验采用同步辐射X射线小角散射法(SR-SAXS)研究纳米Fe、Fe2O3和Fe3O4颗粒及其在磷酸盐缓冲液(PBS)、DMEM培养基分散体系中的粒度分布,并与TEM结果进行比较.结果显示SR-SAXS可准确测试纳米Fe、Fe2O3和Fe3O4颗粒的粒度分布,且不受分散体系和分散浓度的影响.表明SR-SAXS可很好地应用于测试稳定性较差的非均匀分散体系中纳米颗粒的粒度分析.     

宇宙射线缪子核材料快速检测算法研究

根据宇宙射线缪子库伦散射角进行核材料快速检测具有重要意义。本文利用Geant4获取的U、Pb、Fe的缪子库伦散射角数据集，分析缪子散射探测数据的分布特征。使用支持向量机测试了缪子散射探测数据的概率分布函数参数和峭度对不同材料分类的性能，提出基于分布特征的宇宙射线缪子核材料快速检测算法。结果表明，该算法仅用数量为10 000的缪子散射探测数据，能实现对相同厚度的U、Pb、Fe的分类，分类准确率达到989%以上。     

Micro-PIXE investigation of bean seeds to assist micronutrient biofortification

This study compares the distribution and concentrations of micro- and macronutrients in different bean cultivars with the aim of optimizing the biofortification, a sustainable approach towards improving dietary quality. Micro-PIXE was used to reveal the distribution of Fe, Zn, Mn, Ca, P, S in seeds of common beans (Phaseolus vulgaris) and runner beans (Phaseolus coccineus). Average concentrations of elements in different tissues were obtained using ICP-AES. The highest concentrations of Zn in the studied beans were found in the embryonic axis, but an increased concentration of this element was also detected in the provascular bundles of the cotyledons. The first layer of cells surrounding provascular bundles accumulated high concentrations of Fe, while the next cell layer had an increased concentration of Mn. The analysis showed that the provascular bundles and the first cell layers surrounding them could have a significant role in the storage of important seed micronutrients - Zn, Fe, and Mn. This information has important implications for molecular biology studies aimed at seed biofortification.     

Fe distribution and speciation in human nails

Micro-X-ray Fluorescence (μ-XRF) and Fe–K edge micro-X-ray Absorption Near Edge Structure (μ-XANES) spectroscopies are applied for the study of the distribution and the spatially-resolved bonding environment of Fe in human nails. The μ-XRF maps reveal that Fe forms islands where its concentration is up to six times higher than in the rest of the sample. Comparison of the map characteristics of two nails that belong to healthy and ill donors (affected by lung cancer), reveals that there is no significant variation in the size distribution of the Fe-rich inclusions contrary to their spatial density which is found higher in the nail of the ill donor. However, a relation between the variations of the spatial density and the illness can not be established due to the small number of the studied samples. The analysis of the Fe–K μ-XANES spectra reveals that the bonding environment of Fe varies between the samples and between different spots of the same sample with different Fe concentration. The characteristics of the pre-edge peak in the Fe–K XANES spectra indicate the presence of both Fe⁺³ and Fe⁺² that participate in the formation of distorted octahedra. Finally, the area under the pre-edge peak depends linearly on the position of the absorption edge indicating variation of the Fe ligation between the samples and/or between different spots in the same sample.     

Microanalysis of a ductile iron by microchip laser-induced breakdown spectroscopy

Laser beams with ns pulse width are generally employed as an excitation source in the process of detecting inclusions and elemental segregation on a workpiece surface by microanalysis of the laser-induced breakdown spectroscopy.In addition,the ablation crater interval of laser sampling on the sample surface is generally 20 μm or more.It is difficult to detect the morphology of inclusions smaller than 50 μm in diameter and the micro-segregation of elements.However,in this work,when the laser ablation crater is 10 μm and the sampling resolution of the laser on the sample surface is 5 μm,the morphology and distribution of spherical inclusions (20-60 μm) in ductile iron can be detected according to the difference of the Fe spectrum on the Fe matrix and the spheroidal inclusions.Moreover,the distribution of micro-segregation of Mg and Ti elements in ductile iron was also studied.