辐射法制备Pd掺杂碳气凝胶粉末

利用辐射还原法,在100, 200, 500 kGy辐射剂量下制备了金属Pd掺杂的碳气凝胶粉末。X射线衍射（XRD）,扫描电子显微镜（SEM）和能谱测试证实了辐射法成功地制备出Pd掺杂的碳气凝胶粉末复合物。SEM照片表明,还原生成的金属Pd相对均匀地分布在所有碳气凝胶颗粒表面。N2吸附数据分析表明:掺入金属Pd后,碳气凝胶粉末比表面积、平均孔径和总孔体积都显著减小。由于被还原金属大多沉积在碳气凝胶粉末表面,不同辐射剂量下制得的掺杂碳气凝胶粉末的比表面积等多孔特征数据相差不大。     

辐照还原法制备Au掺杂MF气凝胶（英文）

利用辐照还原法在500kGy辐照剂量下制备了Au掺杂MF有机气凝胶。通过X射线衍射(XRD)、能量色散光谱仪(EDX)和透射电子显微镜(TEM)测试证实了辐照法成功地制备出Au掺杂MF有机气凝胶复合物。EDX和TEM照片表明辐照处理后Au纳米颗粒均匀地分布在MF气凝胶骨架中,并且Au纳米颗粒的平均尺寸为5.8nm。N2吸附数据分析表明掺入Au纳米颗粒后,MF气凝胶的比表面积、总孔体积、微孔体积和介孔体积都有所下降。     

辐照还原法制备Au掺杂MF气凝胶

利用辐照还原法在500 kGy辐照剂量下制备了Au掺杂MF有机气凝胶。通过X射线衍射（XRD）、能量色散光谱仪（EDX）和透射电子显微镜（TEM）测试证实了辐照法成功地制备出Au掺杂MF有机气凝胶复合物。EDX和TEM照片表明辐照处理后Au纳米颗粒均匀地分布在MF气凝胶骨架中,并且Au纳米颗粒的平均尺寸为5.8 nm。N2吸附数据分析表明掺入Au纳米颗粒后,MF气凝胶的比表面积、总孔体积、微孔体积和介孔体积都有所下降。     

镍掺杂三聚氰胺-甲醛气凝胶的浸渍-还原法制备

以PdCl2为活化敏化液,水合肼为还原剂,采用化学浸渍-还原法在常温下制得了磁性金属Ni掺杂三聚氰胺-甲醛(MF)气凝胶,为金属掺杂气凝胶的制备寻得了新的途径。利用X-射线粉末衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)等对Ni掺杂MF气凝胶进行表征,SEM和TEM均表明,经浸渍-还原处理后的MF气凝胶骨架中较均匀地分布着粒径约100nm的金属Ni颗粒,其中部分颗粒生长连结形成较大团簇。N2吸-脱附实验数据显示,掺入金属Ni后,MF气凝胶的比表面积、总孔体积、微孔体积均减小,表明浸渍-还原处理后得到的金属Ni颗粒均匀分布于MF气凝胶孔隙中,其中少量大孔的出现是由形成团簇的Ni颗粒填充了部分纯MF气凝胶的孔隙撑开了孔隙结构所致。     

退火温度对Cu:ZnO薄膜绿光发射的影响

利用溶胶-凝胶法在Si衬底上制备了不同退火温度的Cu:ZnO薄膜.利用X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜和光致发光谱研究了样品的晶格结构、表面形貌、成分及其发光特性.结果表明:所有样品均具有高度的c轴择优取向,随着退火温度的升高,样品的结晶质量变好,样品的表面都被晶粒覆盖,强而稳定的绿光发射被观察到.绿光强度随退火温度的升高先增加后减小,发光中心位置不随退火温度的变化而改变,这样的绿光发射强而稳定.XRD和XPS结果表明,随退火温度的升高Cu2+还原为Cu+,导致Cu:ZnO薄膜形成的缺陷是VZn,所以绿光发射是由VZn引起的.Cu2+还原为Cu+时,Cu:ZnO薄膜中VZn浓度增加,使绿光发射强度增大.当退火温度超过800?C时,Cu2+的还原能力变差,绿光发射强度减弱.     

PMP/Cu泡沫材料中Cu颗粒的三维分布

为观测和分析铜掺杂聚-4-甲基-1-戊烯(PMP/Cu)低密度泡沫材料中铜颗粒的三维空间分布,采用高分辨X射线断层扫描技术,扫描PMP/Cu泡沫材料样品,对铜颗粒在聚合物泡沫中的分布进行了成像分析。经过图像处理和三维重构,获得铜颗粒在PMP聚合物泡沫中的三维立体分布图。结果分析显示:铜纳米粒子在PMP泡沫中存在团聚现象;不同尺寸的团聚物形态呈现出明显的多样化特征,小颗粒团聚物趋于球形,大颗粒团聚物趋于不规则的短木棒状,与在电子显微镜下直接观测到的结果一致。研究表明,该技术可以在不破坏样品的前提下,实现对有机聚合物泡沫材料中掺杂金属颗粒空间分布情况的直接观测。     

无催化法制备低密度三聚氰胺-甲醛气凝胶

 以三聚氰胺和多聚甲醛为原料,二甲基亚砜为溶剂制备三聚氰胺-甲醛(MF)气凝胶,湿凝胶经超临界干燥,制备出密度最低可达70 kg/m3的MF气凝胶。采用红外吸收光谱、场发射扫描电镜、N2吸附-脱吸附分析和热失重分析表征了MF气凝胶的组成、微结构以及热性能。结果表明:以二甲基亚砜为溶剂制备的MF气凝胶,虽然其微观结构较以水为溶剂的气凝胶差,比表面积及孔径分布均一性均降低,但是其热稳定性有所提高。     

Cu-Zr合金在氢气氛中退火后表面Cu沉积物的光电子能谱研究

对不同成分的Cu-Zr合金,在超高真空(UHV)和在氢气氛中200—400℃退火后的光电子能谱(XPS)研究发现,与多数情况下因氧感应致使Zr发生表面分凝相反,富铜样品在氢气氛下退火,Cu发生强烈的表面分凝;扫描电子显微镜得出表面Cu沉积物的显微照片,显然,这是由于Cu上氢化吸附热的影响所形成。 关键词：     

一种新型辐射变色膜的γ射线辐照研究

报道了以高聚物为载体，以有机染料及添加剂为变色指示剂体系，制备一种辐射变色膜。这种辐射变色膜为无色透明固体薄膜，经60Co γ射线辐照后，其颜色变为蓝色。辐照后样品的紫外-可见吸收光谱表明，在可见光区其最强吸收峰出现在624 nm附近。在10～90 kGy的剂量范围内，不含添加剂的辐射变色膜的光密度变化与吸收剂量呈线性关系，而含有添加剂的辐射变色膜对γ射线辐照的响应在50 kGy时就达到饱和。同时还探索了该体系辐照效应的化学反应机理。     

Pt/C催化剂中纳米Pt颗粒团聚效应的小角X射线散射

 应用小角X射线散射(SAXS)技术，对乙二醇合成法、浸渍还原法和微波加热法制备的Pt/C催化剂粉体内纳米Pt颗粒的团聚效应进行了研究,得到了不同方法制备的Pt颗粒及其团聚体的特征尺寸、体积分布、表面积变化、团聚程度等信息,并利用透射电镜（TEM）对3种样品进行了测试。实验结果表明:微波加热法制备的催化剂中，Pt颗粒较好地分散于C载体上，且Pt颗粒具有尺度小、分布范围窄、总表面积大和团聚体较少等特征;常规浸渍和乙二醇还原两种方法制备的催化剂中Pt颗粒大小分布相似，但乙二醇还原法制备的催化剂总表面积和团聚体尺度更大,数量也更多。     

Spectrally resolved thermoluminescence of highly irradiated LiF:Mg,Cu,P detectors

Well known, widely applied high sensitive thermoluminescence (TL) detector LiF:Mg,Cu,P (MCP-N) was investigated. This paper analyses changes of the TL emission spectrum of MCP-N after irradiation with ultra high doses (up to 500 kGy). Spectral dependence of TL on dose is very complex especially in the region of very high doses (>1 kGy). As a general trend we found that the number of peaks increases with dose in the long-wavelength region indicating new types of recombination centres (RCs). Wavelength peak positions for increasing doses are quite stable. Only some of them show slight red-shift.     

电子束辐照剂量对PAN/PEO交联度的影响

对PAN/PEO凝胶(5%PAN,5%PEO)在1.0 MeV电子束下进行了不同剂量的辐照。红外光谱测量表明,PAN/PEO凝胶辐照后发生了化学交联。分析结果指出,PAN/PEO的凝胶分数随着辐照剂量的增加而不断增加;其凝胶分数增长率的变化可以分为3个阶段,即快速增加阶段(0~39kGy)、下降阶段(39~130 kGy)和稳定阶段(130 kGy)。拟合发现,引入材料刚性参数β的半经验修正方程与未考虑材料刚性的Char1esby-Pinner方程相比,更符合实际测量值(对于该配比PAN/PEO,β为0.166)。交联度-辐照剂量曲线显示,交联度随辐照剂量的增加而增加,为设计新型能功能材料中所需的固定交联度的PAN/PEO凝胶提供了辐照剂量参考值。     

Thermal and optical properties of electron beam irradiated cellulose triacetate

Samples from Cellulose triacetate (CTA) sheets were irradiated with electron beam in the dose range 10–200 kGy. Non-isothermal studies were carried out using thermogravimetric analysis (TGA) to obtain the activation energy of thermal decomposition for CTA polymer. The CTA samples decompose in one main break down stage. The results indicate that the irradiation by electron beam in the dose range 80–200 kGy increases the thermal stability of the polymer samples. Also, the variation of melting temperatures with the electron dose has been determined using differential thermal analysis (DTA). The CTA polymer is characterized by the appearance of one endothermic peak due to melting. It is found that the irradiation in the dose range 10–80 kGy causes defects generation that splits the crystals depressing the melting temperature, while at higher doses (80–200 kGy), the thickness of crystalline structure (lamellae) is increased, thus the melting temperature increases. In addition, the transmission of these samples in the wavelength range 200–2500 nm, as well as any color changes, were studied. The color intensity ΔE* was greatly increased on increasing the electron beam dose, and accompanied by a significant increase in the blue color component.      

Metal adsorption of gamma-irradiated carboxymethyl cellulose/polyethylene oxide blend films

Blend films of different ratios of carboxymethyl cellulose (CMC)/polyethylene oxide (PEO) were prepared by the solution casting method. To investigate the effect of irradiation on all properties of prepared blend, it was exposed to different gamma irradiation doses (10, 20, and 30?kGy). Physical properties such as gel fraction (GF) (%) and swelling (SW) (%) were investigated. It was found that the GF (%) increases with increasing irradiation dose up to 20?kGy, while SW (%) decreases with an increase in the irradiation doses for all blend compositions. Moreover, the structural and mechanical properties of the prepared films were studied. The results of the mechanical properties obtained showed that there is an improvement in these properties with an increase in both CMC and irradiation dose up to 20?kGy. The efficiency of metal ions uptake was measured using a UV spectrophotometer. The prepared films showed good tendency to absorb and release metal ions from aqueous media. Thus, the CMC/PEO film can be used in agricultural domain.     

用傅立叶变换红外光谱法研究核辐照对人参粉成分的影响

本文采用傅立叶变换红外光谱(吸收光谱、二阶导数谱及差谱)法对经不同剂量核辐照的人参粉进行了对比研究.辐照剂量不高于9 kGy时,人参粉样品的化学成分几乎没有发生变化;人参粉样品经15kGy及以上的辐照剂量辐照后,可能产生新的化学成分,表明采用辐照剂量不高于9 kGy的核辐照杀灭人参粉污染的微生物和各种寄生虫卵是可行的;...     

The Effects of Morphological Properties of Henequen Fiber Irradiated by EB on the Mechanical and Thermal Properties of Henequen Fiber/PP Composites

The aim of this study was to investigate the effects of electron beam (EB) irradiation on the morphological properties, crystallinity and surface area of henequen fiber and on the mechanical and thermal properties of henequen fiber reinforced polypropylene (PP) composites. The structure of henequen fiber was characterized by X-ray diffraction, mercury porosimetry and BET surface area analysis. The EB irradiation of 10 kGy led to the increasing of crystalline and surface pore area of henequen fiber, which contributed to the number of interlocking places with PP. From the results of tensile and impact strength tests, the highest value was observed for the composite reinforced with the henequen fiber treated with EB dose of 10 kGy, decreasing overall as EB dose increased. This tendency was also shown by coefficient of thermal expansion (CTE) measurements, but the value of CTE decreased until 50 kGy, meaning that a large total surface area can provide many interlocking places and so improve adhesion between fiber and matrix. Therefore, it can be concluded that the optimum pore surface area by 10 kGy irradiation contributes to successful mechanical interlocking between fiber and matrix and consequently enhances the mechanical and thermal properties of the composites.     

Influence of high-energy X-ray irradiation on the optical properties of tetraphenylporphyrin thin films

Tetraphenylporphyrin (TPP) thermally evaporated films were irradiated by different doses (0.5–2.5 kGy) of X-ray with energy 6 MeV. The optical properties for TPP were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light in the wavelength range from 200 to 1100 nm. The absorption spectra recorded in the UV-VIS region of spectra showed different absorption bands, namely four Q-bands in the visible region of the spectrum and a more intense band termed as the Soret band in the near-UV region of the spectrum. Two other bands labeled N and M appear in the UV region. The Soret band showed Davydov splitting. Increasing X-ray irradiation dose influences the optical properties of TPP films. All absorption bands show a continuous blue shift in position and a decrease in intensity with increasing X-ray dose. At 2.5 kGy the B, N, and M bands disappeared. The reduction in the absorbency was calculated as a function of X-ray dose. The energy gap was determined and the type of optical transition was found to be an indirect allowed transition.