共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
采用溶胶凝胶法制备了纳米Ti1-xCexO2系列样品。利用X射线衍射(XRD)、透射电子显微镜(TEM)、高分辨电子显微镜(HRTEM)对纳米Ti1-xCexO2系列样品颗粒尺寸、形貌以及固溶区范围和物相组成进行了研究;同时,采用Rietveld结构精修的方法研究了Ce的不同掺杂量对TiO2晶体结构的影响。实验结果表明,Ce掺杂TiO2能够形成Ti1-xCexO2固溶体,Ti1-xCexO2的固溶区范围在x=0~0.06之间,Ti1-xCexO2的晶粒度为5~10 nm,平均颗粒粒度约35 nm,且粒度均匀。 相似文献
4.
SnO2:Zr薄膜对SO2气体的光学气敏特性研究 总被引:1,自引:1,他引:0
采用双靶反应溅射制得SnO2:Zr薄膜,并对它作了150°C下SO2气敏光学特性试验,首次发现在适当工艺条件下制得的SnO2:Zr薄膜在近红外波段(1.7~3μm)对SO2气体具有明显的光学气敏特性,在2.65μm附近透过率上升幅度达10%左右.Zr的引入增强了SnO2薄膜对SO2的吸附能力.用二次离子质谱对吸附SO2前后的薄膜作了组分相对含量分析.本实验结果对今后研究高性能SO2气敏传感器有一定的价值. 相似文献
5.
6.
本文利用X射线粉末衍射和位敏探测技术,研究了R2Fe4/3W2/3O7(R=Er、Yb、Dy)化合物经高温高压处理后的变化情况。在3.7 GPa,1 200 ℃条件下,六方相R2Fe4/3W2/3O7化合物按两种方式分解,而直接由R2O3,Fe2O3和WO3原料出发,经上述同样的高温高压条件合成所得的产物与六方相高温高压分解产物相同,均为R2WO6、RFeO3、WO3和Fe2O3的多相聚合物。同时给出了R2Fe4/3W2/3O7六方相高温高压下的稳定区范围。 相似文献
7.
8.
9.
10.
利用X射线衍射分析和Rietveld结构精修方法研究了基于组分Ca2Pr2Cu5O10三元固溶区的范围和晶体结构。根据X射线分析结果和相消失法,为了保持Ca2+xPr2-xCu5O10结构单位晶胞中恒定的氧含量和电价平衡,基于组分Ca2Pr2Cu5O10的三元固溶区的范围可确定为:在Ca2+xPr2-xCu5O10固溶区的富Ca区(Ca/Pr>1),其表达式仍可以表示为一般的化学计量式Ca2+xPr2-xCu5O10(x=0.4, 0.2, 0);在富Pr区(Ca/Pr<1),其表达式为Ca1.7Pr2.2·Cu5O10、Ca1.4Pr2.4Cu5O10,即:Ca2+xPr2-xCu5O10固溶区范围从Ca2.4Pr1.6Cu5O10至Ca1.4Pr2.4·Cu5O10。研究表明:基于组分Ca2Pr2Cu5O10的三元固溶体晶体结构可以看作是正交晶系NaCuO2型亚晶胞的无公度相;Ca2.4Pr1.6Cu5O10亚晶胞的点阵常数为a0=0.282 46(7) nm,b0=0.636 93(1) nm,c0=1.067 94(1) nm;其正交超结构的点阵常数为a=5a0,b=b0,c=5c0。Ca2.4Pr1.6Cu5O10的结构也可以用单斜超晶胞来表述,该单斜超晶胞的空间群为P21/c,Z=4,a=5a0,b=b0,c=c0/sin β,β=104.79°或136.60°,V=5a0b0c0。在基于组分Ca2Pr2Cu5O10的三元固溶体晶体结构中,Ca和Pr之间在一定范围内是可以相互替代的,而且它们在结构中的占位是无序的。 相似文献
11.
LiuQi-xin ZHAOXin-feng FANGYan 《光散射学报》2005,17(1):46-47
本文在粗糙金属表面上制作了单壁碳纳米管—聚乙烯醇复合材料,并利用表面增强拉曼散射讨论了碳纳米管与聚乙烯醇之间的相互作用 相似文献
12.
Chao Su Feng Xue Fanglin Xu Yuanshi Xin Mingming Wang 《Journal of Macromolecular Science: Physics》2019,58(6):603-618
To improve the wear resistance of carbon fabric reinforced polyimide (CF/PI) composite, surface-modified graphene (MG) was synthesized and employed as a filler. The flexural strength, Rockwell hardness and thermal properties of the composites were tested. The composites were also evaluated for their tribological properties in a ring-on-block contact mode under dry sliding conditions. The results showed that the wear rate of MG reinforced CF/PI composites was reduced when compared to unfilled CF/PI composite. It was found that the 1?wt% MG filled CF/PI composites exhibited the optimal tribological properties. The worn surface, wear debris and transfer films were analyzed by scanning electron microscopy (SEM) and optical microscopy (OM) with the results helping to characterize the wear mechanism. 相似文献
13.
碳纳米管微悬臂梁红外探测器的优化设计 总被引:2,自引:1,他引:1
对复合层微悬臂梁红外探测器进行了理论分析,并建立了相应的理论模型,实验研究了在硅基底上生长碳纳米管的吸热特性,优化设计了一种生长有碳纳米管的三层硅微悬臂梁谐振式红外探测器。该探测器基于复合层微悬臂梁的谐振频率随着微悬臂梁温度的改变发生漂移的特性,在一定的红外辐射下,微悬臂梁的温度会随着辐射光强的强弱而发生变化,从而根据微悬臂梁谐振频率的漂移而感知温度变化实现对辐射光的探测,利用碳纳米管的红外吸收特性,在二层微悬臂梁上生长碳纳米管薄膜作为吸收层,提高了微悬臂梁探测器的红外吸收性能。研究表明:其功率灵敏度可达fw级,比传统的静态测试方法提高了两个数量级。而且这种基于微机电系统技术的传感器与集成电路工艺是兼容的。 相似文献
14.
This paper verifies the feasibility of the relative entropy method in selecting the most suitable statistical distribution for the experimental data, which do not follow an exponential distribution. The efficiency of the relative entropy method is tested through the fractional order moment and the logarithmic moment in terms of the experimental data of carbon fiber/epoxy composites with different stress amplitudes. For better usage of the relative entropy method, the efficient range of its application is also studied. The application results show that the relative entropy method is not very fit for choosing the proper distribution for non-exponential random data when the heavy tail trait of the experimental data is emphasized. It is not consistent with the Kolmogorov–Smirnov test but is consistent with the residual sum of squares in the least squares method whenever it is calculated by the fractional moment or the logarithmic moment. Under different stress amplitudes, the relative entropy method has different performances. 相似文献
15.
D. M. Gureev S. I. Kuznetsov Petrov V. A. Shcheglov 《Journal of Russian Laser Research》2002,23(6):517-530
The conditions for stabilization of the sustaining spot of an electric arc on the surface of metals and carbon-graphite materials in a wide range of laser-radiation intensities are studied. The use of a laser–arc source with a low intensity of laser radiation and a reverse-polarity arc is substantiated physically for efficient surface treatment of metals with emissive coatings and of carbon–carbon composites. 相似文献
16.
Chao-Lu Yin Zheng-Ying Liu Shi-Lin Huang Chen Chen Ming-Bo Yang 《Journal of Macromolecular Science: Physics》2013,52(5):762-772
The effect of isothermal treatment on network formation of nanoscale dispersed carbon black (CB) particles in mild-compounded isotactic polypropylene (iPP)/CB composite is investigated. Network formation of CB took place in a quiescent melt without any flow and expansion since the isothermal treatment of the composite was carried out under high pressure conditions. TEM was used to inspect the network formation of the well-dispersed CB. Resistivity temperature and dynamic rheological behaviors of samples before and after isothermal treatment were examined to investigate the relationship between fillers’ network formation and electrical conductivity enhancement. 相似文献
17.
Linghao He Lu Yao Debin Yang Qingmin Cheng Jing Sun Rui Song 《Journal of Macromolecular Science: Physics》2013,52(12):2454-2463
Composites comprised of chitosan (CS) and multiwalled carbon nanotubes (MWCNTs) were fabricated by milling and ultrasonication dispersion methods. Scanning electron microscopy images showed homogeneous dispersion of MWCNTs throughout the CS matrix for samples prepared by either ultrasonication or milling methods. Further, the crystallinity of the CS component was found to decrease with the addition of MWCNTs, although the decomposition temperature and the storage modulus (E′) of the samples were improved. The decomposition temperature for the composite prepared by milling was 7°C higher than that by the ultrasonication. Meanwhile, the E′ decreased relatively slowly with temperature in the dynamic mechanical analysis measurements. In addition, IR analysis implied an interaction between CS and MWCNTs, which likely originated from hydrogen bonds between the amino, hydroxyl, and carboxyl groups of the two components. Compared with the ultrasonication, milling was more effective to promote the formation of the hydrogen bonds between CS and the MWCNTs and thus enhance the thermal stability of CS. 相似文献
18.
19.
E. Pollatos E. Logakis P. Chatzigeorgiou V. Peoglos I. Zuburtikudis M. Gjoka 《Journal of Macromolecular Science: Physics》2013,52(5):1044-1056
In this work, syndiotactic polypropylene/multiwalled carbon nanotubes (MWCNT) nanocomposites, in various concentrations, were produced using melt mixing. The influence of the addition of MWCNT on the morphology, crystalline form, and the thermal and electrical properties of the polymer matrix was studied. To that aim, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, differential scanning calorimetry, and dielectric relaxation spectroscopy were employed. Significant alterations of both the crystallization behavior and the thermal properties of the matrix were found on addition of the carbon nanotubes: conversion of the disordered crystalline form I to the ordered one, increase of the crystallization temperature and the degree of crystallinity, and decrease of the glass transition temperature and the heat capacity jump. Finally, the electrical percolation threshold was found between 2.5–3.0 wt.% MWCNT. For comparison purposes, the results of the system studied here are also correlated with the findings from a previous work on the isotactic polypropylene/MWCNT system. 相似文献
20.
基于熔融共混法,制备了一系列不同配比且随机分散的Cu/PMMA复合材料,重点研究了Cu颗粒含量对PMMA基体声速与冲击压缩行为的影响。超声测试结果表明,随着Cu颗粒含量的增加,声波的衰减使材料的横、纵波声速皆呈缓慢下降趋势,由此使体积声速亦呈减小趋势。基于平板撞击实验,获得了冲击压力在1.1~6.0 GPa范围内各复合材料的冲击波速度-粒子速度方程。Cu/PMMA复合材料声阻抗的升高使Hugoniot参数λ逐渐增大,而零压体积声速减小,与常压体积声速所表现出的变化趋势一致。结合已有的压力-粒子速度关系模型,对各材料的压力-粒子速度曲线进行了讨论。在此基础上,归纳出一种基于上述模型的用于预测金属粒子填充聚合物基复合材料压力-密度关系的可靠方法。 相似文献