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1.
小角X射线散射(SAXS)是研究多孔材料结构的一种有效方法.可得到孔径分布、平均孔径、比表面、界面层厚度、分形维数等许多微结构信息.SAXS理论公式基于点状光源(针孔准直),但实践中则大多采用长狭缝准直条件.简要综述了SAXS在长狭缝准直条件下直接应用模糊强度进行煤、炭、二凝胶、分子筛等多孔材料结构解析的方法、并与针孔准直进行了对比。  相似文献   

2.
姚熹  张良莹 《物理》1992,21(2):99-105
本文介绍了精细复合功能材料的发展概况和复会材料结构参数(如复合度.联结型、对称性、周期性和标度)的基本概念,讨论了这些结构参数对材料性能的影响;简要地叙述了精细包合功能材料的制备技术,指出了制务技术方面的难点和探索研究的方向;最后扼要地介绍了精细复合功能材料在电子技术中的应用,指出精细复合功能材料可能是一种有价值的光电子材料.  相似文献   

3.
GeSbTe与AglnSbTe体系相变光盘的研究进展   总被引:1,自引:0,他引:1  
自Ovshinsky把相变材料用于光存储以来,一大批具有可逆光存储性能的材料不断出现,其中研究较多的是GeSbTe和AgInSbTe两种体系.文章着重介绍了利用这两种材料制成的相变光盘记录介质的微观结构特点,阐述了其晶化机理;同时,较详细地概述了光盘的堆栈结构及掺杂其他元素对相变光盘性能的影响,并对比说明了GeSbTe和AgInSbTe两种体系在蓝光记录方面的各自特点.  相似文献   

4.
稀土/高分子杂化发光材料的研究   总被引:11,自引:1,他引:10  
用SiO2为无机组份和以与SiO2具有相似折射率和优良力学性能的丙烯酸类如甲基丙烯酸甲酯(MMA)和甲基丙烯酸羟乙酯(HEMA),在交联剂3-(三甲氧基硅)丙基甲基丙烯酸酯(MSMA)存在下,快速制备了两种杂化基质材料SiO2/P(MMA-MSMA)和SiO2/P(HEMA-MSMA)。分别以盐酸和六次甲基四胺作为酸性催化剂和碱性催化剂,建立了快速制备透明凝胶的两步溶胶-凝胶法,大大缩短了溶胶的成胶时间,所得杂化材料具有良好的光学透明性,利用此方法制备了掺杂稀土配合物的多种发光杂化材料。采用组装的方法,得到了稀土配合物与层次化合物α-磷酸氢锆(α-ZrP)及中孔分子筛材料MCM-41的组装体,并对所制备的杂化材料进行了表征。另外,将稀土配合物通过共价键嫁接于无机SiO2基质中,得到了含有稀土配合物的分子杂化材料。  相似文献   

5.
何开元  周飞 《物理》1993,22(9):535-541
从非晶态合金的晶化出发,介绍了最近发展起来的新型优质软磁材料──纳米晶软磁合金.其中包含:(1)非晶态合金的晶化概念以及微晶析出对非晶态合金磁性的影响;(2)纳米晶软磁材料的发现及其具有的优良的综合磁性能;(3)分析了该合金优良磁性能的来源,介绍了目前理论上的解释.最后展望了该合金的发展趋势.  相似文献   

6.
主要开展了高内相乳液法(HIPE)制备有机/无机杂化低密度多孔材料。制备了不同SiO2含量的丙烯酸酯/SiO2杂化多孔材料,研究不同无机含量对杂化材料体积收缩的影响,结果列于表1。  相似文献   

7.
马纪东  朱逢吾 《物理》2002,31(6):353-358
物理学,特别是凝聚态物理学与材料科学的交叉在近几十年已取得丰硕的研究成果,文章分四部分:(1)简要介绍了材料与材料科学的基本概念;(2)回顾近代历史上物理学与材料科学交叉的一些典型例子;(3)介绍在表面和界面、缺陷、理论和模型、微结构表征、新材料以及新工艺等领域物理学与材料科学交叉的简况及材料研究的一些前沿问题;(4)讨论物理学在纳米材料发展中的作用。  相似文献   

8.
有机功能材料的进展   总被引:1,自引:0,他引:1  
吴长勤  孙鑫 《物理》2002,31(8):496-503
介绍了新学科--有机功能材料的发展动态,分析了此学科兴起的原因,具体说明了下述7个方面的进展:(1)有机发光;(2)有机场效应管;(3)塑料电子学;(4)有机激光;(5)量子霍尔效应;(6)有机超导;(7)有机光生伏打效应。最后指出该学科存在的问题。  相似文献   

9.
纳米团聚生长的多重分形谱   总被引:2,自引:0,他引:2       下载免费PDF全文
邵元智  钟伟荣  任山  蔡志苏  龚雷 《物理学报》2005,54(7):3290-3296
采用小角x射线散射(SAXS)方法,对两类具有代表性的纳米团聚的生长分形进行了表征.一 类为用化学方法 (水合肼溶液还原法) 制备的纳米金属Ni粉;另一类通过物理方法(纳米晶 化处理),由非晶基体相中生长纳米晶相、形成非晶/纳米晶双相结构的Finemet (Fe73 .5 Cu1Nb3Si13.5B9) 合金.上述两 类材料的纳米团聚在生长过程中都存在 明显元素扩散迁移,形成在1—100 nm范围内的元素分布非均匀区域.这些元素分布的非均匀 区域具有多重质量生长分形特征,其尺度大小和分布方式对最终的材料的物理性能至关重要 .SAXS方法是表征这类具有分形生长特征的纳米团聚微观结构信息的强有力手段.从方法论的 角度详述了从SAXS测量到获得多重分形谱的处理过程,这一实验研究分析手段对于定量考察 纳米微结构形貌的生长机理和性能的其他研究课题有一定的帮助作用. 关键词: 纳米材料 分形生长 小角x射线散射 磁性材料  相似文献   

10.
TATB含能材料的微结构对该材料的感度等有明显的影响,因而对于材料的安全性有着特别重要的意义.小角X射线散射(SAXS)技术是一种分析物质微观结构的重要手段,应用SAXS分析技术可以获取材料中几纳米到几百纳米尺度范围的亚微结构信息.利用同步辐射作为X射线源对TATB钝感炸药进行了小角散射实验测量,获得了SAXS测量谱.对实验谱数据进行处理,可得到样品材料的颗粒分布及内部微孔大小等微结构参数.  相似文献   

11.
Small angle X-ray scattering has been utilised to study the structure of hematite aggregates. The small angle X-ray scattering (SAXS) spectra obtained provided insight into structure of the hematite aggregates and the size of the primary particles. The structural analysis results obtained by SAXS are consistent with previous results obtained from static light scattering studies. Both techniques indicate that the mass fractal dimensions of hematite aggregates are markedly higher than those obtained for other particle systems.  相似文献   

12.
《Composite Interfaces》2013,20(3):199-213
'In situ' wide angle (WAXS) and small angle X-ray scattering (SAXS) studies were carried out to characterize the structural changes occurring during the conversion of a polyamic acid into the polyimide in the presence of fullerene, C60. The variations in crystallinity, long period, and the SAXS invariant of the samples are discussed in the light of the various temperature ranges studied. The conversion of the polyamic acid into the polyimide is analyzed according to the different structural steps. Results reveal that C60 affects the degree of order of the composite in the molecular direction, giving rise to slightly smaller crystals than those found in pure polyamic acid. The difference in the SAXS data between the pure PAA and the composite are discussed through the interaction of C60 molecules with the polyamic acid, which seems to hinder the imidization reaction up to 185°C.  相似文献   

13.
Ordered mesoporous silicas (OMSs) such as SBA-15 (p6mm symmetry group) synthesized in the presence of block copolymers containing poly(ethylene oxide) blocks possess irregular complementary pores in the walls of ordered mesopores. The X-ray scattering caused by this complementary porosity contributes to the background of the SAXS patterns. This work shows the possibility of using the SAXS data for the study of intrawall channels interconnecting ordered cylinders in SBA-15. The proposed SAXS analysis was tested by using a series of SBA-15 samples obtained at different temperatures of hydrothermal treatment (from 60 to 180 °C). The structural modelling of the SAXS patterns recorded for a series of SBA-15 samples was performed by using the continuous density function (CDF) technique in combination with the derivative difference minimization (DDM) method of full-profile refinement. This method is well suited for extraction of the background curves from the SAXS patterns. The resulting smooth background curves were analyzed by the well-known method in the SAXS theory used for evaluation of heterogeneity distributions, which in this case characterize the intrawall complementary porosity. A relatively good agreement has been observed between the data obtained by SAXS and nitrogen adsorption analysis. The SAXS analysis is sufficiently sensitive for examination of heterogeneous microporosity in SBA-15 materials. The average diameter of intrawall pores for the SBA-15 sample obtained at 60 °C was only about 1.4 nm. However, this diameter increased with the increasing temperature of hydrothermal treatment; namely, it was 1.5, 1.8, 2.6, 2.6, 3.5 and 5.2 nm for the SBA-15 samples hydrothermally treated at 80, 100, 120, 140, 160 and 180 °C, respectively.  相似文献   

14.
小角X光散射是当X光照射到物质上时发生的在原光束附近小角度范围内的电子相干散射,凡是存在纳米尺度的电子密度不均匀区的物质均会产生小角X光散射现象,因此它是表征纳米、多孔材料结构的理想手段。SAXS中的有关理论一般仅适用于稀疏体系,对于密集体系,往往会产生干涉现象。本文简要总结了目前文献中有关干涉效应的判断与处理方法。  相似文献   

15.
The negative templating synthesis process has been applied to prepare nanostructured carbon materials with a high nitrogen content. SBA-15 silica template was impregnated with the following carbon precursors: sucrose, glucose and amino-glucose. The structure of the materials was investigated by SAXS, WAXS and TEM. Nitrogen functions were analyzed by XPS and the textural parameters of the carbons were studied by nitrogen and CO2 adsorption. X-ray and TEM studies confirmed that a pore nanostructure is inherited from the silica templates. XPS analysis showed that the nitrogen content of the materials can be controlled between 2 and 5 wt% and that N atoms are strongly bonded in the carbon structure in heterocycles or nitrile functions. An important result is that these nanostructured carbon materials exhibits interesting textural properties with BET surface areas ranging between 1000 and . Moreover, the study of the influence of nitrogen on the textural and structural parameters of the resulting carbon materials shows that nitrogen plays an active role during the synthesis process. This observation is also supported by the speciation of nitrogen in the nanostructured carbon materials.  相似文献   

16.
Biological small-angle X-ray scattering (SAXS) provides powerful complementary data for macromolecular crystallography (MX) by defining shape, conformation and assembly in solution. Although SAXS is in principle the highest throughput technique for structural biology, data collection is limited in practice by current data collection software. Here the adaption of beamline control software, historically developed for MX beamlines, for the efficient operation and high-throughput data collection at synchrotron SAXS beamlines is reported. The Blu-Ice GUI and Distributed Control System (DCS) developed in the Macromolecular Crystallography Group at the Stanford Synchrotron Radiation Laboratory has been optimized, extended and enhanced to suit the specific needs of the biological SAXS endstation at the SIBYLS beamline at the Advanced Light Source. The customizations reported here provide a potential route for other SAXS beamlines in need of robust and efficient beamline control software. As a great deal of effort and optimization has gone into crystallographic software, the adaption and extension of crystallographic software may prove to be a general strategy to provide advanced SAXS software for the synchrotron community. In this way effort can be put into optimizing features for SAXS rather than reproducing those that have already been successfully implemented for the crystallographic community.  相似文献   

17.
Elucidating the structure of large biomolecules such as multi-domain proteins or protein complexes is challenging due to their high flexibility in solution. Recently, an "integrative structural biology" approach has been proposed, which aims to determine the protein structure and characterize protein flexibility by combining complementary high- and lowresolution experimental data using computer simulations. Small-angle x-ray scattering(SAXS) is an efficient technique that can yield low-resolution structural information, including protein size and shape. Here, we review computational methods that integrate SAXS with other experimental datasets for structural modeling. Finally, we provide a case study of determination of the structure of a protein complex formed between the tandem SH3 domains in c-Cb1-associated protein and the proline-rich loop in human vinculin.  相似文献   

18.
我国同步辐射小角X光散射装置   总被引:1,自引:0,他引:1  
小角X光散射是当X光照射到物质上时发生的在原光束附近小角度范围内的电子相干散射,凡是存在纳米尺度的电子密度不均匀区的物质均会产生小角X光散射现象,因此它是表征纳米、多孔材料结构的理想手段。普通X光源产生的X光强度弱,限制了小角X光散射的应用,采用同步辐射为X光源,则可以大大提高X光强度。目前我国已建立同步辐射小角X光散射站,本文对其装置进行了介绍。  相似文献   

19.
We study asymmetric block copolymers with the simple diblock AB architecture, in the case where the longer block A is both hydrophobic and “soft”, whereas the shorter block B is hydrophilic and “hard”. Materials with such a particular combination of physico-chemical and mechanical properties have distinctive advantages, in particular for designing water-compatible adhesive materials. The phase diagram is established, combining NMR and SAXS characterisations of the materials. The swelling with water is monitored through gravimetry and “time-resolved” SAXS. Indications of maintained adhesive properties in a wet environment are given.  相似文献   

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