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Small Angle X-ray Scattering Study of Precipitation Kinetics in Al-Zn-Mg-Cu Alloys 被引量:3
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作者 Zhiwei DU Tietao ZHOU +3 位作者 Peiying LIU Huanxi LI Baozhong DONG Changqi CHEN 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第4期479-483,共5页
The evolution of microstructure parameters (precipitate size and volume fraction) for two types of Al-Zn-Mg-Cu alloys (7075 and 7055) during aging has been studied by synchrotron-radiation small angle X-ray scatte... The evolution of microstructure parameters (precipitate size and volume fraction) for two types of Al-Zn-Mg-Cu alloys (7075 and 7055) during aging has been studied by synchrotron-radiation small angle X-ray scattering (SAXS).The results show that the precipitates are only a few nanorneters for both alloys ageing even at higher temperature of 160℃ for 72 h (4.44 and 5.82 nm, respectively). The maximum of the precipitate volume fraction increases with in creasing Zn content and is about 0.023-0.028 and 0.052-0.054, respectively. The coarsening of precipitate is consistent with LSW (Lifshitz-Slyozov-Wagner) model even at the initial stage where volume fraction is still varying.The activation energy of coarsening regime has been determined to be about 1.22±0.02 eV and 1.25±0.02 eV for alloys 7075 and 7055, respectively. 展开更多
关键词 small angle x-ray scattering (SAXS) AI-Zn-Mg-Cu alloys Ageing Precipitate size Volume fraction
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Small-angle X-ray scattering investigation of aging behavior of Al-Cu-Mg-Ag alloys using synchrotron radiation 被引量:3
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作者 Zhang Jianbo Zhang Yongan +3 位作者 Zhu Baohong Liu Ruiqing Li Zhihui Li Xiwu 《Rare Metals》 SCIE EI CAS CSCD 2012年第6期537-540,共4页
The aging behavior of Al-Cu-Mg-Ag alloys with high Cu/Mg was studied by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) using synchrotron radiation. TEM study reveals that the major stre... The aging behavior of Al-Cu-Mg-Ag alloys with high Cu/Mg was studied by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) using synchrotron radiation. TEM study reveals that the major strengthening phases of the alloy after aging at 160?C for 10 h are Ω and less θ′. SAXS study shows that the scattering patterns are composed of several concentric circles at the beginning of aging process, which is replaced by the butterfly-wings scattering patterns with the increase of aging time. The butterfly-wings scattering patterns are composed of several branches. The angles between the branches are roughly equal to that between the habit planes of precipitates. The evolution of Guinier radius with aging time indicates the good coarsening resistance of the precipitates. The evolution of integrated intensity is consistent with the classical two-step precipitation process. 展开更多
关键词 Al-Cu-Mg-Ag alloys precipitate size synchrotron radiation small angle x-ray scattering
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Growth Kinetics of Nanocrystals and Nanorods by Employing Small-angle X-ray Scattering (SAXS) and Other Techniques 被引量:2
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作者 Kanishka BISWAS Neenu VARGHESE C.N.R.Rao 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第4期615-627,共13页
In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering (S... In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering (SAXS), transmission electron microscopy (TEM) along with other physical techniques. The study includes growth kinetics of gold nanocrystals formed by the reduction of HAuCl4 by tetrakis(hydroxymethyl) phosphonium chloride in aqueous solution, of CdSe nanocrystals formed by the reaction of cadmium stearate and selenium under solvothermal conditions, and of ZnO nanorods formed by the reaction of zinc acetate with sodium hydroxide under solvothermal conditions in the absence and presence of capping agents. The growth of gold nanocrystals does not follow the diffusion-limited Ostwald ripening, and instead follows a Sigmoidal rate curve. The heat change associated with the growth determined by isothermal titration calorimetry is about 10 kcal·mol^-1 per I nm increase in the diameter of the nanocrystals. In the case of CdSe nanocrystals also, the growth mechanism deviates from diffusion-limited growth and follows a combined model containing both diffusion and surface reaction terms. Our study of the growth kinetics of uncapped and poly(vinyl pyrollidone) (PVP)-capped ZnO nanorods has yielded interesting insights. We observe small nanocrystals next to the ZnO nanorods after a lapse of time in addition to periodic focusing and defocusing of the width of the length distribution. These observations lend support to the diffusion-limited growth model for the growth of uncapped ZnO nanorods. Accordingly, the time dependence on the length of uncapped nanorods follows the L3 law as required for diffusion-limited Ostwald ripening. The PVP-capped nanorods, however, show a time dependence, which is best described by a combination of diffusion (L^3) and surface reaction (L^2) terms. 展开更多
关键词 Growth kinetics Gold nanocrystals CdSe nanocrystals ZnO nanorods small angle x-ray scattering Transmission electron microscopy Ostwald ripening and sigmoidal growth
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Small Angle X-ray Scattering Study of PS Conformation in Tetrahydrofuran Solvent with Gas Anti-solvent 被引量:1
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作者 Dan LI Zhi Min LIU +5 位作者 Guan Ying YANG Qing HUO Bu Xing HAN Yi LIU Zhong Hua WU Bao Zhong DONG 《Chinese Chemical Letters》 SCIE CAS CSCD 2000年第12期1093-1094,共2页
Small angle X-ray scattering (SAXS) was used to study the effect of dissolved CO2 on the conformation of polystyrene (PS) in PS/tetrahydrofuran(THF) solution at 308.15 K and at pressures up to 3 MPa. The cloud pressur... Small angle X-ray scattering (SAXS) was used to study the effect of dissolved CO2 on the conformation of polystyrene (PS) in PS/tetrahydrofuran(THF) solution at 308.15 K and at pressures up to 3 MPa. The cloud pressure and the expansion curve of the solution were also determined. The dependence of the conformation on pressure was discussed. 展开更多
关键词 small angle x-ray scattering POLYSTYRENE THF CO2 CONFORMATION
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Scanning Microfocus Small Angle X-ray Scattering Study of the Avian Eggshell
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作者 D. Lammie M. M. Bain +1 位作者 S. E. Solomon T. J. Wess 《Journal of Bionic Engineering》 SCIE EI CSCD 2006年第1期11-18,共8页
Synchrotron microfocus small angle X-ray scattering was used to investigate the nanostructure and microscopic variation of eggshells. It uses a microbeam allowing the ability to probe interactions between the organic ... Synchrotron microfocus small angle X-ray scattering was used to investigate the nanostructure and microscopic variation of eggshells. It uses a microbeam allowing the ability to probe interactions between the organic and inorganic components at nanometer level and is ideal for mapping over small areas to obtain a detailed analysis of structural variations. Thin sections of eggshells were scanned from the shell membrane (inner) to the cuticle (outer) surface. The data collected was used to produce two-dimensional maps showing microscopic changes within the different layers of the eggshell. The structural alterations ap- parently could have implications at the macroscopic level of the resulting eggshell. As the organic matrix is embedded within the eggshell this may contribute to the variations observed in calcite crystal form and texture, Structural information obtained about a biomaterial at different length scales is important in relating the structure to its functional properties. This knowledge and the principles behind the formation of biomaterials could be used in the attempt of bioengineering new systems. 展开更多
关键词 biomaterial EGGSHELL NANOSTRUCTURE microfocus small angle x-ray scattering
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Characteristics of AOT Microemulsion Structure: a Small Angle X-ray Scattering Study
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作者 Jun Cheng LIU Gan Zuo LI Bu Xing HAN 《Chinese Chemical Letters》 SCIE CAS CSCD 2001年第11期1023-1026,共2页
The method of synchrotron radiation small-angle X-ray scattering (SR-SAXS) has been used to obtain structural information on the system of bis (2-ethylhexyl) sulfosuccinate (AOT)/H2O/isooctane. By using the Guinier pl... The method of synchrotron radiation small-angle X-ray scattering (SR-SAXS) has been used to obtain structural information on the system of bis (2-ethylhexyl) sulfosuccinate (AOT)/H2O/isooctane. By using the Guinier plot (Ln I (q) versus q(2)) on the data sets in a defined small q range (0.03-0.06 Angstrom (-1)), the gyration radius at different water/surfactant molar ratio, W-0, was obtained. With the increase of W-0, the gyration radius (R-g) increased at the range of 23.2 similar to 52.7 Angstrom. 展开更多
关键词 bis(2-ethylhexyl)suffosuccinate(AOT) MICROEMULSION gyration radius small angle x-ray scattering
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Probing Nanoscale Morphology of PS/PMMA/CdS &PS/PVC/CdS Polymeric Nanocomposites through Small Angle X-Ray Scattering Analysis
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作者 Vishal Mathur Kananbala Sharma 《Modern Instrumentation》 2014年第4期25-28,共4页
Polymeric nanocomposites of PS/PMMA/CdS and PS/PVC/CdS samples have been synthesized through dispersion solution casting technique. The nanoparrticles of CdS were prepared by simple chemical method using CdCl2 and H2S... Polymeric nanocomposites of PS/PMMA/CdS and PS/PVC/CdS samples have been synthesized through dispersion solution casting technique. The nanoparrticles of CdS were prepared by simple chemical method using CdCl2 and H2S gas produced from thiourea. The nanoscale morphology of the prepared polymeric nanocomposite samples is probed through small angle X-ray scattering (SAXS). The SAXS study reveals that CdS nanoparticles take place at voids position in the respective plymer blend matrix and exhibit their nano nature with very little tendency to agglomerates. 展开更多
关键词 small angle x-ray scattering POLYMER NANOCOMPOSITE CDS Nanoparticles POLYMER Characterization
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Stability of the Dividing Distribution Function Method for ParticleSize Distribution Analysis in Small Angle X-Ray Scattering 被引量:2
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作者 Zhang Jinyuan Liu Chunlan Chen Yan 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 1996年第1期51-52,63+54-55,共5页
The Dividing Distribution Function (DDF) method is one of the methods by which the particle size distribution of ultrafine powder can be evaluated from its small angle X-ray scattering data. In this paper, the stabili... The Dividing Distribution Function (DDF) method is one of the methods by which the particle size distribution of ultrafine powder can be evaluated from its small angle X-ray scattering data. In this paper, the stability of the solution obtained from DDF method has been investigated through optimizing the coefficient matrix, introducing a damping factor and a least square treatment. All calculations were accomplished with a microcomputer. It was shown that the average deviations of the size distribution obtained are not larger than the assigned random errors to the scattering intensities as long as the corresponding requirements are satisfied. 展开更多
关键词 ultrafine powder particle size distribution small angle x-ray scattering dividing distribution function method
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Nano-scale pore distribution characterisation of coal using small angle X-ray scattering
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作者 Peng Jia Jinzhang Jia Sadegh Nadimi 《Particuology》 SCIE EI CAS CSCD 2023年第10期73-85,共13页
In the process of coal seam fracturing with liquid nitrogen(LN_(2)),the change of coal pore structure has an important influence on the efficiency of coalbed methane(CBM)extraction.The nano-scale pore size distributio... In the process of coal seam fracturing with liquid nitrogen(LN_(2)),the change of coal pore structure has an important influence on the efficiency of coalbed methane(CBM)extraction.The nano-scale pore size distribution(PSD)in coal particles before and after freezing with LN_(2) are experimentally studied in this work.Coal samples are collected from four coal mines,where coal and gas outburst accidents have occurred.Small angle X-ray scattering technology(SAXS)and scanning electron microscopy(SEM)are used to study the pore structure changes of coal samples quantitatively and qualitatively.It is found that the scattering intensity of coal samples increases after freezing.The PSD of all samples significantly changes in the range of 0.8–7 nm,showing new pore spaces in 0.8–4 nm and fewer pores in the 4–7 nm range.Both the pore fractal dimension and the radius of gyration of coal samples increase after freezing and are mainly affected by the changes in pores and the anisotropy of the coal matrix.Crack expansion and pore connections are observed in the surface structure of the coal sample using SEM.This study provides a better understanding of the nano-scale mechanism of coal seam fracturing with LN_(2) for the prevention of coal and gas outbursts. 展开更多
关键词 Coalbed methane small angle x-ray scattering LN2 freezing Pore size distribution(PSD) Particle characterisation Fractal dimension
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Small angle X-ray scattering of the colloidal crystal 被引量:1
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作者 蓝鼎 王育人 +2 位作者 张荫民 王维 吴忠华 《Chinese Physics C》 SCIE CAS CSCD 2009年第11期1016-1018,共3页
The monodisperse polystyrene spheres are assembled into the colloidal crystal on the glass substrate by vertical deposition method, which is aimed at the so-called photonic crystal applications. The structural informa... The monodisperse polystyrene spheres are assembled into the colloidal crystal on the glass substrate by vertical deposition method, which is aimed at the so-called photonic crystal applications. The structural information of the bulk colloidal crystal is crucial for understanding the crystal growth mechanism and devel- oping the various applications of colloidal crystal. Small-angle X-ray scattering (SAXS) technique was used to obtain the bulk structure of the colloidal crystal at Beamline lW2A of BSRF. It is found that the SAXS pattern is sensitive to the relative orientation between the colloidal sample and the incident X-ray direction. The crystal lattice was well distinguished and determined by the SAXS data. 展开更多
关键词 colloidal crystal small angle x-ray scattering photonic crystal
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DETERMINATION OF SIZE DISTRIBUTION OF THE CRYSTALLINE PARTICLE IN AGED METALLIC GLASS BY SMALL ANGLE X-RAY SCATTERING
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作者 孟昭富 《Chinese Science Bulletin》 SCIE EI CAS 1992年第11期958-961,共4页
Ⅰ. INTRODUCTIONAlthough many authors have investigated the structure of annealed metallic glass by means of small angle X-ray scattering (SAXS), there has been no report in which size distribution of the crystalline ... Ⅰ. INTRODUCTIONAlthough many authors have investigated the structure of annealed metallic glass by means of small angle X-ray scattering (SAXS), there has been no report in which size distribution of the crystalline particle in aged metallic glass is determined. Determining size distribution of the crystalline particle will be beneficial to understanding the nucleation and growth process of the crystalline particle. In this note, size distribution of the crystalline parti- 展开更多
关键词 small angle x-ray scattering METALLIC glass size distribution of the CRYSTALLINE PARTICLE
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DETERMINATION OF THE SHAPE AND DIMENSION OF PRECIPITATE FROM AGED Lc4 ALUMINIUM ALLOY BY SMALL ANGLE X-RAY SCATTERING
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作者 孟昭富 《Chinese Science Bulletin》 SCIE EI CAS 1989年第17期1489-1493,共5页
Small angle X-ray scattering (SAXS) is extensively used for determining the dimension of a particle, but rarely used for determining its shape. The difficulty is that it needs to do extensive calculations. In addition... Small angle X-ray scattering (SAXS) is extensively used for determining the dimension of a particle, but rarely used for determining its shape. The difficulty is that it needs to do extensive calculations. In addition, it can only be carried out for the mono-dispersion system. In re cent years, Reuther et al. succeeded in determining the shape and dimension of the particle of a polymer gel. 展开更多
关键词 small angle x-ray scattering aluminium alloy SHAPE of PARTICLE DIMENSION of PARTICLE
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Characterization of the nanopore structures of PAN-based carbon fiber precursors by small angle X-ray scattering
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作者 王德红 郝俊杰 +4 位作者 邢雪青 默广 宫宇 吕春祥 吴忠华 《Chinese Physics C》 SCIE CAS CSCD 2011年第9期870-874,共5页
The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments (A), water-washing filaments (B) hot-stretchin... The nanopore structures in precursors Four carbon-fiber precursors are prepared. They are crucial to the performance of PAN-based carbon fibers are bath-fed filaments (A), water-washing filaments (B) hot-stretching filaments (C) and drying-densification filaments (D). Synchrotron radiation small angle X-ray scattering is used to probe and compare the nanopore structures of the four fibers. The nanopore size, discrete volume distribution, nanopore orientation degree along the fiber axis and the porosity are obtained. The results demonstrate that the nanopores are mainly formed in the water-washing stage. During the processes of the subsequent production technologies, the slenderness ratio of nanopores and their orientation degree along the fiber axis increase further and simultaneously, the porosity decreases. These results are helpful for improving the performance of the final carbon fibers. 展开更多
关键词 PAN-based carbon fiber precursor small angle x-ray scattering nanopore structure POROSITY
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Influence of energy bandwidth of pink beam on small angle X-ray scattering
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作者 Shanfeng Wang Yaxiang Liang +4 位作者 Bingjie Wang Weiwei Dong Lingfei Hu Qun Ouyang Peng Liu 《Radiation Detection Technology and Methods》 CSCD 2019年第1期19-26,共8页
Background Compared with the traditional monochromatic synchrotron radiation beam,a pink beam is a quasimonochromatic beam which can be obtained by screening a harmonic of the undulator.The energy bandwidth(E/E)of a ... Background Compared with the traditional monochromatic synchrotron radiation beam,a pink beam is a quasimonochromatic beam which can be obtained by screening a harmonic of the undulator.The energy bandwidth(E/E)of a pink beam is about 10−2.Despite the intensity gain from the quasi-monochromatic beam,the decrease in the energy resolution will lead the collected data to be smeared.Purpose To study the influence of the energy bandwidth on the small angle X-ray scattering(SAXS)by experiments and verify the feasibility of SAXS with a pink beam.Method Firstly,the influence of different energy bandwidths on SAXS has been studied by simulation and experiment.Then,TEM tests have been performed and compared with the experimental results.Result It has been shown that the scattering curves deviate slightly from the traditional monochromatic ones.This deviation does not influence the data processing for the maximum deviation of the results is just less than 2%.In return,the gain in the intensity(one to two orders of magnitude)makes the pink beam very important for the time-resolved SAXS.Further,the results of TEM and SAXS have shown an excellent agreement.Conclusion Thiswork proves that the pink beam could be used for SAXS directly without a desmearing procedure.Benefiting from the increase in the beam intensity,the exposure time can be greatly shortened,thus enhancing the utilization efficiency of the synchrotron radiation. 展开更多
关键词 small angle x-ray scattering(SAXS) Pink beam Adjustable energy bandwidth Smeared effect
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In-situ SAXS study on PET/PMMT composites during tensile tests
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作者 程伟东 顾晓华 +5 位作者 宋雪 曾鹏 吴昭君 邢雪青 默广 吴忠华 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第1期783-788,共6页
The nanostructures during the tensile drawing of poly(ethylene terephthalate) (PET)/hexadecyl triphenyl phospho- nium bromide montmorillonite (PMMT) nanocomposites were studied by in-situ small angle x-ray scatt... The nanostructures during the tensile drawing of poly(ethylene terephthalate) (PET)/hexadecyl triphenyl phospho- nium bromide montmorillonite (PMMT) nanocomposites were studied by in-situ small angle x-ray scattering. For strain higher than the yield point, the scattering intensity increases dramatically due to the nucleation and growth of nanovoids and crystals. The nanovoids and crystals are significantly dependent on the heating temperature. The effective filling of PMMT in the PET matrix provokes a strong restriction to the long period. The peaks of the long period disappear gradually with the deformation strain increasing from 0% to 34%. 展开更多
关键词 small angle x-ray scattering NANOSTRUCTURE MONTMORILLONITE poly(ethylene terephthalate)
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Determination of Average Wall Thickness of Mesoporous Silica 被引量:2
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作者 Zhi Hong LI Yan Jun GONG +4 位作者 Dong WU Yu Han SUN Jun WANG Yi LIU Bao Zhong DONG 《Chinese Chemical Letters》 SCIE CAS CSCD 2001年第8期741-744,共4页
Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEO... Small Angle X-ray Scattering (SAXS) experiment using Synchrotron Radiation as X-ray source was used to determine the average wall thickness of mesoporous silica prepared by condensation of tetraethylorthosilicate (TEOS) using non-ionic alkylpolyethyleneoxide (AEO(9)) surfactant as templates. The results agreed with that of high-resolution TEM (HRTEM) measurement. 展开更多
关键词 small angle x-ray scattering(SAXS) mesoporous silica average wall thickness
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Properties,Morphology and Structure of BPDA/PPD/TFMB Polyimide Fibers 被引量:1
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作者 HUANG Sen-biao GAO Zhong-min +3 位作者 MA Xiao-ye GUO Hai-quan QIU Xue-peng GAO Lian-xun 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第4期752-756,共5页
The mechanical properties of fibers were notably improved by incorporating 2,2'-bis(trifluoromethyl)benzidine(TFMB) into 3,3',4,4'-biphenyltetracarboxylic dianhydride(s-BPDA) and p-phenylenediamine(PPD) bac... The mechanical properties of fibers were notably improved by incorporating 2,2'-bis(trifluoromethyl)benzidine(TFMB) into 3,3',4,4'-biphenyltetracarboxylic dianhydride(s-BPDA) and p-phenylenediamine(PPD) backbone.The best strength and modulus of BPDA/PPD/TFMB polyimide(PI) fiber(diamine molar ratio of PPD/TFMB= 90/10) were 1.60 and 90 GPa,respectively,which was over two times that of BPDA/PPD PI fiber.SEM image showed that the cross-section of fibers at each stage was round and voids free.Besides,the "skin-core" and microfibrillar structure were not observed.The thermal properties of PI fibers were also investigated.The results showed that the fibers owned excellent thermal stability,moreover,the structural homogeneity of fibers were significantly improved by heat-drawn stage.The T g values were found to be around 300 °C by dynamic mechanical analysis(DMA).Wide angle X-ray diffraction(WAXD) and small angle X-ray scattering(SAXS) experiments indicated that the order degree of longitudinal and lateral stacks,the molecular orientation and the structural homogeneity of fibers were improved in the preparation process of fibers. 展开更多
关键词 Polyimide fiber Scanning electron microscopy(SEM) Wide angle x-ray diffraction(WAXD) small angle x-ray scattering(SAXS)
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Monodisperse hollow silica spheres: An in-depth scattering analysis
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作者 Pia Ruckdeschel Martin Dulle +3 位作者 Tobias Honold Stephan Forster Matthias Karg Markus Retsch 《Nano Research》 SCIE EI CAS CSCD 2016年第5期1366-1376,共11页
Herein, we fabricate hollow silica nanoparticles with exceptionally narrow size distributions that inherently possess two distinct length scales-tens of nanometers with regards to the shell thickness, and hundreds of ... Herein, we fabricate hollow silica nanoparticles with exceptionally narrow size distributions that inherently possess two distinct length scales-tens of nanometers with regards to the shell thickness, and hundreds of nanometers in regards to the total diameter. We characterize these structures using dynamic and static light scattering (DLS and SLS), small angle X-ray scattering (SAXS), and transmission electron microscopy (TEM), and we demonstrate quantitative agreement among all methods. The ratio between the radius of gyration (SLS) and hydrodynamic radius (DLS) in these particles equals almost unity, corresponding to ideal capsule behavior. We are able to resolve up to 20 diffraction orders of the hollow sphere form factor in SAXS, indicating a narrow size distribution. Data from light and X-ray scattering can be combined to a master curve covering a q-range of four orders of magnitude assessing all hierarchical length scales of the form factor. The measured SLS intensity profiles noticeably change when the scattering contrast between the interior and exterior is altered, whereas the SAXS intensity profiles do not show any significant change. Tight control of the aforementioned length scales in one simple and robust colloidal building block renders these particles suitable as future calibration standards. 展开更多
关键词 hollow sphere silica nanoparticle small angle x-ray scattering light scattering nanoscale characterization
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STABILIZATION, REFORMATION AND MELTING OF POLY(L-LACTIDE) CRYSTALLITES
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作者 Tai-Yon Cho Barbara Heck Gert Strobl 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第1期83-94,共12页
The large size of the crystallites in poly(L-lactide) and the low growth rate enable detailed time- and temperaturedependent X-ray scattering studies of the ordering processes to be carded out. A layer located inter... The large size of the crystallites in poly(L-lactide) and the low growth rate enable detailed time- and temperaturedependent X-ray scattering studies of the ordering processes to be carded out. A layer located intermediate between crystals and melt-like regions is observed which finally takes on crystalline order. Recrystallization processes during heating change the complete stack structure rather than the crystallites individually and produce voids in the stacks, Establishment of a new stable structure after a temperature jump in the melting range can be followed in time. DSC experiments indicate times of melting of the order of minutes. 展开更多
关键词 Poly(L-lactide) Polymer crystallization small angle x-ray scattering Semicrystalline structure.
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Evaluation of Average Wall Thickness of Organically Modified Mesoporous Silica
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作者 YanJunGONG ZhiHongLI BaoZhongDONG 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第1期139-142,共4页
The small angle X-ray scattering of organically modified MSU-X silica prepared by co-condensation of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) show negative deviation from Debye’s theory due to the ... The small angle X-ray scattering of organically modified MSU-X silica prepared by co-condensation of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) show negative deviation from Debye’s theory due to the existence of the organic interface layer. By exerting correction of the scattering negative deviation, Debye relation may be recovered, and the average wall thickness of the material may be evaluated. 展开更多
关键词 Organically modified mesoporous silica average wall thickness small angle x-ray scattering (SAXS).
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