CoFe2O4磁性液体的正电子湮没谱分析

对ＣｏＦｅ２Ｏ４磁性液体进行了正电子湮没谱研究，结果显示，ＣｏＦｅ２Ｏ４磁性液的正电了湮没谱存在３种寿命成分，分别为τ１＝１５１．０ｐｓ，τ２＝１５１．０ｐｓ，τ３＝２３２５．６ｐｓ。表明在ＣｏＦｅ２Ｏ４超微粒表面存在大量空位和空位团。     

Cr和Mo对Fe3Al合金中微观缺陷和电子密度的影响

测量了二元Ｆｅ３Ａｌ及含Ｃｒ或Ｍｏ的Ｆｅ３Ａｌ合金的正电子寿命谱参数,计算了合金基体和缺陷处的价电子密度。实验结果表明,Ａｌ和Ｆｅ结合形成Ｆｅ３Ａｌ合金时,Ａｌ原子提供价电子与Ｆｅ原子的３ｄ电子形成局域的共价键。Ｆｅ３Ａｌ合金中金属键和共价键共存。Ｆｅ３Ａｌ合金晶界缺陷的开空间大于Ｆｅ空位或Ａｌ空位的开空间,晶界缺陷处价电子密度比基体低,晶界的键合力较弱。在Ｆｅ３Ａｌ合金中加入Ｍｏ,降低了合金中的     

脉冲Ti＋C双重离子注入抗磨损优化结构的研究

大剂量Ｔｉ＋、Ｃ＋和Ｔｉ＋＋Ｃ＋注入Ｈ１３钢可使注入层硬度和抗磨损寿命明显增加，尤以Ｔｉ＋＋Ｃ＋双注入效果最佳．实验结果表明注入的Ｔｉ和Ｃ原子浓度可分别达到２２％和４５％；超饱和Ｔｉ和Ｃ浓度形成了固溶强化；注入层中已形成弥散的硬化相，如Ｆｅ２Ｔｉ、ＴｉＣ、Ｆｅ２Ｃ和Ｆｅ５Ｃ２等，出现了弥散强化效果．注入层表面形成了一层２０ｎｍ厚的薄碳层，使之呈现出自滑润特性。     

掺杂Y2O3的铁锡复合氧化物的穆斯堡尔谱学研究

采用化学共沉淀法合成α－Ｆｅ２Ｏ３－ＳｎＯ２和α－Ｆｅ２Ｏ３－ＳｎＯ２－Ｙ２Ｏ３的铁锡复合氧化物,应用Ｘ射线衍射和穆斯堡尔谱学等手段研究材料的微结构和微粒生长情况,实验结果表明,掺杂Ｙ２Ｏ３对晶粒生长有明显抑制作用,不同温度热处理可制得不同尺寸大小的纳米晶α－Ｆｅ２Ｏ３－ＳｎＯ２－Ｙ２Ｏ３材料。     

N_2~+、N~+与Cu基底中α-Fe纳米颗粒相互作用的穆斯堡尔谱研究

利用穆斯堡尔方法研究了Ｎ２＋、Ｎ＋与 Ｃｕ基底中α－Ｆｅ纳米颗粒相互碰撞和碰撞后的热动力学过程。实验结果表明，Ｎ２＋与α－Ｆｅ纳米颗粒的相互作用存在着明显的非线性，即Ｎ２＋与α－ Ｆｅ纳米颗粒的碰撞截面，远大于 Ｎ＋与α－ Ｆｅ纳米颗粒的碰撞截面。     

放射性废有机溶剂（TBP／OK）稳定化技术研究

磷酸三丁酯／煤油废有机溶剂是核设施产生的中低放废物之一。本文研究了废溶剂在Ｈ２Ｏ２－Ｆｅ＾２＋／ＴｉＯ２－Ｈ２ＳＯ４体系中的氧化分解行为，分析了Ｈ２Ｏ２用量，催化剂，温度，ｐＨ值等主控因素对反应进程及结果的影响。     

纳米SnO2和SnO2／SiO2材料的正电子湮没研究

采用溶胶一凝胶法制备了纯纳米ＳｎＯ２和掺杂ＳｉＯ２的纳米ＳｎＯ２材料，应用Ｘ射线衍射和正电子湮没寿命谱等手段进行了纳米材料的界面结构和纳米晶粒的生长过程，结果表明，所制备的纳米ＳｎＯ２和ＳｎＯ２／ＳｉＯ２材料中只存在两类缺陷，分别对短寿命τ１和中等寿命τ２，材料中两类缺陷的数量比与粒径有关，纳米ＳｎＯ２晶粒生长随热处理温度升高为分两个阶段，低于晶化临界温度时，晶粒生长缓慢，高于此温度时，则生长迅速     

Si基体上双层Ti－O薄膜的XPS和AES分析研究

采用沉积－离子轰击－沉积工艺制备了双层Ｔｉ－Ｏ薄膜，并利用ＸＰＳ和ＡＥＳ对膜层进行了深度分析．结果发现：在氩离子轰击后的薄膜上再沉积同质薄膜，在膜表层一定厚度内可得到具有化学配比的ＴｉＯ２薄膜；氩离子的轰击使钛及碳氧化物内迁入Ｓｉ基体，而Ｓｉ外迁到膜内，并造成多价形式的Ｔｉ氧化物共存，ＴｉＯ２在这些Ｔｉ氧化物中所占的比例随沉积膜深度呈现先逐渐减少而后又逐渐增大的分布规律；此外，氩离子的轰击使得薄膜与基体在界面处形成较宽的、复杂的混合层．混合层主要由ＴｉＯ２、Ｔｉ２Ｏ３、ＴｉＯ、未氧化完全的ＳｉＯ２－ｘ及纯Ｓｉ组成。     

用正电子湮没技术研究Ni－20Al－30Fe合金中的缺陷组态

测量了铸态、热轧和定向结晶三种不同工艺的Ｎｉ－２０Ａｌ－３０Ｆｅ的ｅ＋寿命谱：ｅ＋这三种试样的缺陷中的寿命十分相近．说明ｅ＋在该合金的空位、应错和晶界中的寿命相近．合金晶界缺陷处的自由电子密度和空位处的相当。在ＮｉＡｌ合金中加入Ｆｅ元素后．改善了合金的晶界结构．     

EDXRF法直接测定铁氧体中MnO,ZnO和Fe2O3的含量

用ＥＤＸＲＦ法直接测定锰锌铁氧体中ＭｎＯ、ＺｎＯ和Ｆｅ２Ｏ３含量是采用软、硬件相结合的办法，成功地分解ＭｉｌＫ和ＦｅＫ重迭峰，并对特定基体效应提出具体对策。由２３８Ｐｕ同位素源和正比计数管组成的探测系统，对ＭｎＯ、ＺｎＯ和Ｆｅ２Ｏ３的测量准确度分别为０．１４％、０．１０％和０．１７％。     

热压纳米晶铜的硬度性能

采用自悬浮定向流法制备纳米铜粉末,利用不同的工艺参数在真空热压炉中压制成直径一定厚度不同的纳米晶体铜圆柱体。通过XRD、SEM、分析天平、硬度仪等分析测试手段,研究了块体硬度与晶粒大小、密度、晶体结构的关系。结果表明：较薄块体硬度随晶粒长大而降低,两者关系基本符合Hall-Petch经验公式;较厚块体各区域密度差异不明显,受表面缺陷状态及晶粒大小影响,其各处硬度差异较大（1.4～2.2GPa）。     

碳同素异形体的康普顿轮廓研究

本文介绍了用康普顿散射方法研究碳同素异形体的电子动量密度分布。实验中得到了碳不同结构材料的康普顿轮廓,发现由于晶体结构、成键方式的不同,它们的核外电子动量有着较显著的区别,纳米材料的表面效应表现明显。     

Formation process of β-SiC during reaction-sintering

Reaction-sintered bodies of β-SiC were prepared from various carbon powders, such as non-graphitizable carbon, petroleum coke, artificial graphite and kish graphite. The maximum particle size of carbon powder that can be completely siliconized was estimated from the difference of particle size distribution between carbon raw materials and unreacted carbon observed in the reaction-sintered bodies. The lattice strain of β-SiC formed in situ was measured by an X-ray line broadening method. It was suggested from these data that the formation process of β-SiC during the reaction-sintering was influenced by the microstructure of carbon raw materials; the crystallite size and the degree of preferred orientation of crystallite.     

纳米晶Al的快中子辐照效应研究

采用真空热压技术将自悬浮定向流法制得的纳米Al粉压制成平均晶粒尺寸约为120nm的块体,并对其进行了注量为1.9×1012~7.2×1014 cm-2的快中子(E1 MeV)辐照。通过X射线衍射(XRD)分析、扫描电子显微镜与能谱(SEM-EDS)分析和显微硬度测试研究了快中子辐照对纳米晶Al的微观结构和显微硬度的影响。研究结果表明:快中子辐照同时造成了纳米晶Al的平均晶粒尺寸增大和显微硬度提高。随快中子辐照注量的增大,纳米晶Al的平均晶粒尺寸和显微硬度分别增大了2.09%~9.09%和3.54%~4.37%。纳米晶Al的平均晶粒尺寸的增长率随快中子注量的增加而增大。     

在水和乙醇体系中用辐射技术制备纳米ZnS晶体

在水溶液体系和乙醇溶液体系中，于常温常压下不加入任何催化剂，用γ射线辐照技术可以成功制备出纳米ZnS晶体，其中硫代硫酸钠和二硫化碳分别为上述两体系的硫源。本工作利用XRD和TEM来分析观察纳米ZnS晶体的结构和形貌，产物具有立方体结构和球型的形貌，颗粒大小在20－50纳米之间。根据实验，提出了纳米ZnS晶体在不同体系中形成的机理。     

单相纳米金属间化合物AlNi的制备及其结构特征

采用自悬浮定向流法制备单相金属间化合物AlNi的纳米微粉,通过TEM、XRD和元素化学分析等检测手段对微粒材料的显微结构、相组成和成分构成进行研究。所制备的纳米颗粒呈规则球形,粒径分布在10～40nm之间,样品中的Al、Ni原子比为49∶51,颗粒基本由单相AlNi组成。实验证实,通过控制气相反应的工艺条件可有效避免单质Al和Ni的生成。     

Thermoluminescence and photoluminescence of cerium doped CaSO4 nanosheets

Thermoluminescence (TL) and photoluminescence (PL) characteristics of CaSO₄:Ce nanocrystalline prepared by hydrothermal method has been studied. Its TL glow curve contains three overlapping glow peaks at around 490, 505 and 521 K. Emission spectra band at 303 and 324 nm were observed for the orthorhombic phase of nanosheets. TL response of the prepared nanocrystalline to β and γ radiation was studied and the sensitivity of the nanosheets was found much more than that of analogous microcrystalline and is around 10 times higher than the well known high sensitive TL dosimeter LiF:Mg, Cu, P (GR-200) hot-pressed chips. TL kinetic parameters of this nanocrystalline are also presented.     

Surface contamination of the charge－coupled device

An experimental method to study the influence of surface contamination of a thinned.backside illuminated charge-coupled device(CCD) upon its quantum efficiency in soft X-ray region is suggested.A transmission grating spectrometer(TGS),in which the transmission grating is coupled to a thinned.backside illuminated charge coupled device,is used to measure the continuum X-ray emission from the end of cylindrical target irradiated by laser.In the meausred spectra,only the carbon K absorption edge at wavelength of 4.4nm due to condensation of the vacuum oil on the CCD surface is clearly seen.The surface contamination is considered as an effective “carbon filter” and the filter absorption to correct the quantum efficiency of the CCD camera is taken into account.The effective thickness of the carbon filter is determined by comparing the jump height of the measured spectra at 4.4nm with those of the carbon absorption coefficient curves obtained from various carbon thickness.The accuracy of this method is tested by comparing the X-ray spectrum measured by the TGS with that obtained by a soft X-ray spectrometer.     

Thermoluminescence properties of nanocrystalline K2Ca2(SO4)3:Eu irradiated with gamma rays and proton beam

Thermoluminescence properties of nanocrystalline K₂Ca₂(SO₄)₃:Eu prepared by ball milling technique have been studied and the nanophosphor’s suitability as an effective gamma radiation and proton beam dosimeter material has been examined. It is found that the nanophosphor is suitable for dosimetry over a very wide range of doses ∼1 Gy to 1 kGy for gamma radiation. And for proton beam the same nanophosphor shows a more or less linear response for the dose range 0.1-100 Gy. A comparative study of this nanophosphor with its corresponding microcrystalline form (prepared by solid-state diffusion method) as well as the nanocrystalline form prepared by (the more conventional) co-precipitation technique has shown that the nanophosphor prepared by the ball milling technique is in almost all respects better than the other two forms reported earlier.     

Plasma-enhanced Deposition of Nano-Structured Carbon Films

By pre-treating substrate with different methods and patterning the catalyst, selective and patterned growth of diamond and graphitic nano-structured carbon films have been realized through DC Plasma-Enhanced Hot Filament Chemical Vapor Deposition (PE-HFCVD). Through two-step processing in an HFCVD reactor, novel nano-structured composite diamond films containing a nanocrystaUine diamond layer on the top of a nanocone diamond layer have been synthesized. Well-aligned carbon nanotubes, diamond and graphitic carbon nanocones with controllable alignment orientations have been synthesized by using PE-HFCVD. The orientation of the nanostructures can be controlled by adjusting the working pressure. In a Microwave Plasma Enhanced Chemical Vapor Deposition (MW-PECVD) reactor, high-quality diamond films have been synthesized at low temperatures (310 ℃ - 550 ℃) without adding oxygen or halogen gas in a newly developed processing technique. In this process, carbon source originates from graphite etching, instead of hydrocarbon. The lowest growth temperature for the growth of nanocrystalline diamond films with a reasonable growth rate without addition of oxygen or halogen is 260 ℃.