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SnO_2-based solid solutions for CH_4 deep oxidation: Quantifying the lattice capacity of SnO_2 using an X-ray diffraction extrapolation method
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作者 孙琪 徐香兰 +5 位作者 彭洪根 方修忠 刘文明 应家伟 余帆 王翔 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第8期1293-1302,共10页
A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M (M=Mn, Zr, Ti and Pb) molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3+, ... A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M (M=Mn, Zr, Ti and Pb) molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3+, Zr4+, Ti4+and Pb4+cations are incorporated into the lattice of tetragonal rutile SnO2 to form a solid solution structure. As a consequence, the surface area and thermal stability of the catalysts are improved. Moreover, the oxygen species of the modified catalysts become easier to be reduced. Therefore, the oxidation activity over the catalysts was improved, except for the one modified by Pb oxide. Manganese oxide demonstrates the best promotional effects for SnO2. Using an X‐ray diffraction extrapolation method, the lattice capacity of SnO2 for Mn2O3 was 0.135 g Mn2O3/g SnO2, which indicates that to form stable solid solution, only 21%Sn4+cations in the lattice can be maximally replaced by Mn3+. If the amount of Mn3+cations is over the capacity, Mn2O3 will be formed, which is not favorable for the activity of the catalysts. The Sn rich samples with only Sn‐Mn solid solution phase show higher activity than the ones with excess Mn2O3 species. 展开更多
关键词 SnO2-based solid solution x-ray diffraction extrapolation method Lattice capacity Methane deep oxidation Carbon monoxide oxidation
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Influence of Replacement Level of Coal-series Kaolin on Hydration of Ordinary Portland Cement by X-ray Diffraction/Rietveld Method 被引量:1
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作者 LIU Yuanyuan LEI Shaomin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第3期614-621,共8页
The influence of replacement level of calcined coal-series kaolin(CCK) on hydration of ordinary Portland cement(OPC) was studied by X-ray diffraction(XRD)/Rietveld method. X-ray diffraction/Rietveld method was used to... The influence of replacement level of calcined coal-series kaolin(CCK) on hydration of ordinary Portland cement(OPC) was studied by X-ray diffraction(XRD)/Rietveld method. X-ray diffraction/Rietveld method was used to quantify the crystalline phase composition of the hydrated samples. Additionally, the morphology of hydrated samples was observed by scanning electron microscopy(SEM). The results showed that, calcium hydroxide(CH), ettringite(AFt) and amorphous phase content in hydrated samples decreased as the replacement level of CCK increased, while AFm and str?tlingite increased, which was caused by the combination of dilute, physical and pozzolanic effects. The hydration of anhydrous cement phases was accelerated by physical effect but hindered by the retardation effect of CCK. The role of each effects was discussed in detail to analyze the mechanism of OPC hydration with CCK addition. The SEM images showed that the shortening of AFt at 1 day and the denser texture at 28 days was observed with CCK addition, which was caused by the physical and pozzolanic effects, respectively. 展开更多
关键词 CALCINED coal-series KAOLIN x-ray diffraction/rietveld method HYDRATION cement PASTE morphology
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Fitting Full X-Ray Diffraction Patterns for Quantitative Analysis: A Method for Readily Quantifying Crystalline and Disordered Phases 被引量:3
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作者 Steve J. Chipera David L. Bish 《Advances in Materials Physics and Chemistry》 2013年第1期47-53,共7页
Fitting of full X-ray diffraction patterns is an effective method for quantifying abundances during X-ray diffraction (XRD) analyses. The method is based on the principal that the observed diffraction pattern is the s... Fitting of full X-ray diffraction patterns is an effective method for quantifying abundances during X-ray diffraction (XRD) analyses. The method is based on the principal that the observed diffraction pattern is the sum of the individual phases that compose the sample. By adding an internal standard (usually corundum) to both the observed patterns and to those for individual pure phases (standards), all patterns can all be normalized to an equivalent intensity based on the internal standard intensity. Using least-squares refinement, the individual phase proportions are varied until an optimal match is reached. As the fitting of full patterns uses the entire pattern, including background, disordered and amorphous phases are explicitly considered as individual phases, with their individual intensity profiles or “amorphous humps” included in the refinement. The method can be applied not only to samples that contain well-ordered materials, but it is particularly well suited for samples containing amorphous and/or disordered materials. In cases with extremely disordered materials where no crystal structure is available for Rietveld refinement or there is no unique intensity area that can be measured for a traditional RIR analysis, full-pattern fitting may be the best or only way to readily obtain quantitative results. This approach is also applicable in cases where there are several coexisting highly disordered phases. As all phases are considered as discrete individual components, abundances are not constrained to sum to 100%. 展开更多
关键词 Full-Pattern QUANTITATIVE x-ray diffraction xrd
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Characterization of Average Molecular Structure of Heavy Oil Fractions by ~1H Nuclear Magnetic Resonance and X-ray Diffraction 被引量:2
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作者 Ren Wenpo Yang Chaohe Shan Honghong 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2011年第3期1-7,共7页
The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of... The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of asphaltene molecules were estimated by combining 1 H nuclear magnetic resonance and X-ray diffraction analyses,and were also ob-tained from vapor pressure osmometry and elemental analysis.Heteroatoms,such as S,N,and O atoms,were considered in the construction of average molecular structure of heavy oils.Two important structural parameters were proposed,including the number of alkyl chain substituents to aromatic rings and the number of total rings with heteroatoms.Ultimately,the av-erage molecular structures of polycyclic aromatics,heavy resins and asphaltene molecules were constructed.The number of α-,β-,γ-,and aromatic hydrogen atoms of the constructed average molecular structures fits well with the number of hydro-gen atoms derived from the experimental spectral data. 展开更多
关键词 heavy oil ASPHALTENE nuclear magnetic resonance (NMR) x-ray diffraction (xrd average molecular structure
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Microfibril angle variability in Masson Pine (Pinus massoniana Lamb.) using X-ray diffraction 被引量:1
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作者 Zhang Bo Fei Ben-hua +1 位作者 Yu Yan Zhao Rong-jun 《Forestry Studies in China》 CAS 2007年第1期33-38,共6页
The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray... The microfibril angle of fiber walls is an ultra-mieroscopic feature affecting the performance of wood products. It is therefore essential to get more definitive information to improve selection and utilization. X-ray diffraction is a rapid method for measuring microfibril angles. In this paper, the variability of microfibril angle in plantation-grown Masson pine was investigated by peak-fitting method. This method was compared with the traditional hand-drawn method, 40% peak height method and half peak height method. X-ray diffraction measurements indicated that the microfibril angle changed as a function of the position in the tree. The mean microfibril angle decreased more gradually as the distance increased from the pith and reached the same level in mature wood. The microfibril angle also seemed to decrease clearly from the base upward. Differences of angle-intensity curves between heartwood and sapwood were also examined. 展开更多
关键词 x-ray diffraction microfibril angle peak-fitting method half peak height method Masson pine
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X-Ray Diffraction, Electron Paramagnetic Resonance and Optical Absorption Study of Bauxite 被引量:1
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作者 Tanguturi Ravindra Reddy Krishnan Thyagarajan +2 位作者 Ovidio Almanza Montero Sanapa Reddy Lakshmi Reddy Tamio Endo 《Journal of Minerals and Materials Characterization and Engineering》 2014年第2期114-120,共7页
The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be g... The bauxite mineral obtained from Araku, Vishakapatnam district of Andhra Pradesh, India is used in the present work. Structural characterization was performed by X-ray diffraction (XRD). The mineral was found to be gibbsite in phase. The transitional metal ions present were investigated using electron paramagnetic resonance (EPR) and optical absorption spectra. The EPR results suggest that Fe3+ has replaced Al3+ in the unit cell of bauxite. The optical absorption spectrum is due to Fe3+ which indicates that it is in distorted octahedral environment. The near-infrared (NIR) spectrum is due to water fundamentals and combination overtones, which confirm the formula of the compound. The impurities in the mineral are identified using spectroscopic techniques. 展开更多
关键词 BAUXITE GIBBSITE x-ray diffraction (xrd) ELECTRON PARAMAGNETIC ELECTRON PARAMAGNETIC Resonance Optical Absorption Spectra FE3+ Water Fundamentals
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X-Ray Powder Diffraction: Why Not Use CuKβ Radiation?
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作者 Hans Hermann Otto 《Journal of Analytical Sciences, Methods and Instrumentation》 2018年第3期37-47,共11页
CuKβ radiation with a wavelength of λ = 1.3923 ? is recommended for crystal structure determination from X-ray powder diffraction using the Rietfeld method. A highly sensitive image plate detector is able to collect... CuKβ radiation with a wavelength of λ = 1.3923 ? is recommended for crystal structure determination from X-ray powder diffraction using the Rietfeld method. A highly sensitive image plate detector is able to collect enough intensity to record a brilliant X-ray powder pattern in a reasonable time, compared to CuKα1 radiation used today. Especially atomic displacement coefficients could be determined more precisely with the much greater number of reflections recorded. A double-radius Guinier camera attached to a micro-focus rotating anode tube ensures increased brilliance besides high resolution. A simple construction specification is presented to make smart cylindrically bent Ge(111) or Si(111) X-ray monochromators that deliver focused CuKβ radiation. The highly linear response of image plate detectors allows removing of fluorescence radiation simply as background of the pattern. The proposed equipment is a cost-efficient alternative to a liquid gallium-metal-jet X-ray source with maximum power load and a similar wavelength of λ(GaKα1) = 1.34013 ?. 展开更多
关键词 x-ray diffraction Rietfeld Analysis CuKβ RADIATION Guinier method FOCUSING MONOCHROMATORS x-ray diffraction Equipment Construction
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Microstructural origins of high strength of Al-Si alloy manufactured by laser powder bed fusion:In-situ synchrotron radiation X-ray diffraction approach 被引量:1
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作者 Naoki Takata Mulin Liu +4 位作者 Masahiro Hirata Asuka Suzuki Makoto Kobashi Masaki Kato Hiroki Adachi 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2024年第11期80-89,共10页
The microstructural factors contributing to the high strength of additive-manufactured Al-Si alloys us-ing laser-beam powder bed fusion(PBF-LB)were identified by in-situ synchrotron X-ray diffraction in tensile deform... The microstructural factors contributing to the high strength of additive-manufactured Al-Si alloys us-ing laser-beam powder bed fusion(PBF-LB)were identified by in-situ synchrotron X-ray diffraction in tensile deformation and transmission electron microscopy.PBF-LB and heat treatment were employed to manufacture Al-12%Si binary alloy specimens with different microstructures.At an early stage of de-formation prior to macroscopic yielding,stress was dominantly partitioned into the α-Al matrix,rather than the Si phase in all specimens.Highly concentrated Si solute(~3%)in the α-Al matrix promoted the dynamic precipitation of nanoscale Si phase during loading,thereby increasing the yield strength.After macroscopic yielding,the partitioned stress in the Si phase monotonically increased in the strain-hardening regime with an increase in the dislocation density in the α-Al matrix.At a later stage of strain hardening,the flow curves of the partitioned stress in the Si phase yielded stress relaxation owing to plastic deformation.Therefore,Si-phase particles localized along the cell walls in the cellular-solidified microstructure play a significant role in dislocation obstacles for strain hardening.Compared with the results of the heat-treated specimens with different microstructural factors,the dominant strengthening factors of PBF-LB manufactured Al-Si alloys were discussed. 展开更多
关键词 Laser powder bed fusion Aluminum alloys Microstructures x-ray diffraction(xrd) Strain hardening
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Method for Measuring Residual Stresses Induced by Boring in Internal Surface of Tube and Its Validation with XRD Method 被引量:13
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作者 孟龙晖 何宁 +2 位作者 杨吟飞 赵威 戎斌 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2014年第5期508-514,共7页
Residual stresses can have a strong effect on the usability of machined parts,and the X-ray diffraction(XRD)measuring equipment,which is commonly used to measure residual stresses,is very expensive.This paper presents... Residual stresses can have a strong effect on the usability of machined parts,and the X-ray diffraction(XRD)measuring equipment,which is commonly used to measure residual stresses,is very expensive.This paper presents a method of measuring the residual stresses induced by boring in the internal surface of a tube with much cheaper equipment.The method,called the strain-based method is mainly based on the strains measured on the external surface of the tube.It is proposed on the basis of the very long tube assumption.The finite element method(FEM)analysis is thus used to validate the length of the tube.Guided by the FEM results,an appropriate length of the tube is chosen,and the residual stresses are obtained from both the strain-based method and the XRD method.Stress profiles obtained from both two methods are compared.The comparison result indicates that the profiles of the two methods agree well with each other.Therefore,it can be concluded that the accuracy of the strain-based method is high enough,and it can be applied to residual stress measurement in practice. 展开更多
关键词 residual stress finite element method(FEM) strain element birth and death x-ray diffraction (xrd)
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Crystallographic Characteristic of Intermetallic Compounds in Al-Si-Mg Casting Alloys Using Electron Backscatter Diffraction 被引量:2
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作者 ZOU Yongzhi XU Zhengbing +1 位作者 HE Juan ZENG Jianmin 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2010年第3期305-311,共7页
The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mecha... The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5(Fe, Mn)3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope(OM), scanning electron microscope(SEM), energy dispersive X-ray spectrometer(EDS), electron backscatter diffraction(EBSD) and X-ray powder diffraction(XRD). The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P6_2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys. 展开更多
关键词 Al-Si-Mg alloys intermetallic compound electron backscatter diffraction(EBSD) x-ray powder diffraction(xrd
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X-Ray Analysis by Williamson-Hall and Size-Strain Plot Methods of ZnO Nanoparticles with Fuel Variation 被引量:3
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作者 Yendrapati Taraka Prabhu Kalagadda Venkateswara Rao +1 位作者 Vemula Sesha Sai Kumar Bandla Siva Kumari 《World Journal of Nano Science and Engineering》 2014年第1期21-28,共8页
In this paper, a simple and facile surfactant assisted combustion synthesis is reported for the ZnO nanoparticles. The synthesis of ZnO-NPs has been done with the assistance of non-ionic surfactant TWEEN 80. The effec... In this paper, a simple and facile surfactant assisted combustion synthesis is reported for the ZnO nanoparticles. The synthesis of ZnO-NPs has been done with the assistance of non-ionic surfactant TWEEN 80. The effect of fuel variations and comparative study of fuel urea and glycine have been studied by using characterization techniques like X-ray diffraction (XRD), transmission electron microscope (TEM) and particle size analyzer. From XRD, it indicates the presence of hexagonal wurtzite structure for ZnO-NPs. Using X-ray broadening, crystallite sizes and lattice strain on the peak broadening of ZnO-NPs were studied by using Williamson-Hall (W-H) analysis and size-strain plot. Strain, stress and energy density parameters were calculated for the XRD peaks of all the samples using (UDM), uniform stress deformation model (USDM), uniform deformation energy density model (UDEDM) and by the size-strain plot method (SSP). The results of mean particle size showed an inter correlation with W-H analysis, SSP, particle analyzer and TEM results. 展开更多
关键词 SURFACTANT Assisted Combustion x-ray diffraction (xrd) Transmission Electron MICROSCOPE (TEM) Particle ANALYZER
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Analytical solution of crystal diffraction intensity
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作者 Wan-Li Shang Ao Sun +13 位作者 Hua-Bin Du Guo-Hong Yang Min-Xi Wei Xu-Fei Xie Xing-Sen Che Li-Fei Hou Wen-Hai Zhang Miao Li Jun Shi Feng Wang Hai-En He Jia-Min Yang Shao-En Jiang Bao-Han Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第11期430-433,共4页
Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal,and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness.In this study,... Plasma density and temperature can be diagnosed by x-ray line emission measurement with crystal,and bent crystals such as von Hamos and Hall structures are proposed to improve the diffraction brightness.In this study,a straightforward solution for the focusing schemes of flat and bent crystals is provided.Simulations with XOP code are performed to validate the analytical model,and good agreements are achieved.The von Hamos or multi-cone crystal can lead to several hundred times intensity enhancements for a 200μm plasma source.This model benefits the applications of the focusing bent crystals. 展开更多
关键词 crystal diffraction analytic method x-ray diffraction
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Comparative Study on the Defects of Kaolinite from America,Brazil and China Applied for Paper Coating:XRD and Refinement by Rietveld Method
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作者 朱小燕 ZHU Zhichao +2 位作者 LEI Xinrong YAN Chunjie CHEN Jieyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第2期373-377,共5页
Three kaolinite samples applied for paper coating were collected from America(KA),Brazil(KB),and China(KC),respectively.Parameters such as average bond length of Si-O and Al-O(1(Si-O) and1((Al-O))),tetra... Three kaolinite samples applied for paper coating were collected from America(KA),Brazil(KB),and China(KC),respectively.Parameters such as average bond length of Si-O and Al-O(1(Si-O) and1((Al-O))),tetrahedral rotation angles(α),changes of tetrahedral flattemng angles(τ) and octahedral flattemng angles(ψ) comparative to ideal angle,particle layer thickness(T) and basal z corrugation(Δz) were analyzed by XRD and Rietveld method.The experimental results indicated that △z(KA)〉△z(KC)〉△z(KB).KB has a regular structure and KA has a disorder structure,α(KA)〉α(KC)〉α(KB),△τ(KA)〉△τ(KC)〉△τ(KB),and △ψ(KA)〉△ψ(KB)〉△ψ(KC).KA has unstable tetrahedron and octahedron.KB and KC have stable tetrahedron and octahedron,respectively.In the process of manufacture,kaolinite structure may be broken from places with unstable tetrahedron and octahedron.l(Si-O)(KA) 〉l(Si-O)(KB)〉l(Si-O)(KC) and 1(A1-O)KA〉1(A1-O)(KC)〉1(A1-O)(KB).What only considered is the effect of bond length,KA may be most easily broken in the manufacture.Compared with bond lengths of KA and KB,Si-O,and Al-O of KB and KC may be easily broken,respectively.T(KA) 展开更多
关键词 x-ray diffraction rietveld method defects distortion
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硼砂煅制工艺优化及质量评价
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作者 杨辛欣 洪禹昕 +5 位作者 张睿 赵晶丽 刘佳 王楚盈 许天阳 于澎 《中成药》 CAS CSCD 北大核心 2024年第2期404-410,共7页
目的 优化硼砂煅制工艺,并对其进行质量评价。方法 以铺设厚度、煅制温度、煅制时间为影响因素,失水率、蓬松度、粉碎率、四硼酸钠含量为评价指标,星点设计-效应面法优化硼砂煅制工艺。采用扫描电镜(SEM)、热重分析(TG)、拉曼光谱、X射... 目的 优化硼砂煅制工艺,并对其进行质量评价。方法 以铺设厚度、煅制温度、煅制时间为影响因素,失水率、蓬松度、粉碎率、四硼酸钠含量为评价指标,星点设计-效应面法优化硼砂煅制工艺。采用扫描电镜(SEM)、热重分析(TG)、拉曼光谱、X射线衍射(XRD),比较硼砂煅制前后质量差异。结果 最佳条件为铺设厚度2 cm,煅制温度365℃,煅制时间100 min。煅制后,硼砂微观形态、成分组成、晶型结构发生变化,失去全部结晶水而转变为非晶体状态。结论 该方法稳定可行,可用于工业大批量生产煅硼砂。 展开更多
关键词 硼砂 煅制工艺 星点设计-效应面法 扫描电镜(SEM) 热重分析(TG) 拉曼光谱 X射线衍射(xrd)
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化学共沉淀法制备磁性活性炭及XRD分析 被引量:7
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作者 刘军 杜茹男 +3 位作者 武一 侯佳男 黄爽 孙剑平 《沈阳建筑大学学报(自然科学版)》 CAS CSCD 北大核心 2017年第2期378-384,共7页
目的优化化学共沉淀法制备磁性活性炭复合材料的最佳制备条件,确定制备高纯度磁性活性炭的主要因素.方法通过控制反应温度、pH值、粉末活性炭不同的投加顺序和不同的搅拌条件制备出相应的磁性活性炭复合材料;并对所制备的磁性活性炭复... 目的优化化学共沉淀法制备磁性活性炭复合材料的最佳制备条件,确定制备高纯度磁性活性炭的主要因素.方法通过控制反应温度、pH值、粉末活性炭不同的投加顺序和不同的搅拌条件制备出相应的磁性活性炭复合材料;并对所制备的磁性活性炭复合材料进行X射线衍射分析表征(XRD),同时利用扫描电子显微镜(SEM)对最佳条件下制备的磁性活性炭材料进行形貌分析.结果制备磁性活性炭的最佳条件为:机械搅拌、反应温度为70℃、pH值为9及滴加沉淀剂(Na OH)前投加粉末活性炭.结论反应温度、pH值、粉末活性炭的投加顺序及搅拌条件是化学共沉淀法制备磁性活性炭的影响因素.在不同的影响因素下粉末活性炭表面负载磁性物质的纯度有一定的差别,其中pH值是决定生成高纯磁性物质的主要因素. 展开更多
关键词 化学共沉淀法 磁性活性炭 X射线衍射 磁性物质
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XRD和TG-DTG-DTA在CA砂浆沥青含量及组分分析中的应用 被引量:3
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作者 杨凯 邱秀姣 +2 位作者 瞿福林 曾晓辉 王平 《建筑材料学报》 EI CAS CSCD 北大核心 2017年第5期820-826,共7页
为计算长期运营环境下水泥乳化沥青砂浆(CA砂浆)中沥青含量并分析其组分变化,对CA砂浆粉末样品进行了X射线衍射(XRD)、热重(TG)、微商热重(DTG)和差热分析(DTA),并对比了空气和氮气氛围中CA砂浆的热分析曲线.发现在空气氛围中对CA砂浆... 为计算长期运营环境下水泥乳化沥青砂浆(CA砂浆)中沥青含量并分析其组分变化,对CA砂浆粉末样品进行了X射线衍射(XRD)、热重(TG)、微商热重(DTG)和差热分析(DTA),并对比了空气和氮气氛围中CA砂浆的热分析曲线.发现在空气氛围中对CA砂浆样品进行热分析,并根据热重(TG)、微商热重(DTG)和差热分析(DTA)曲线特征采用二组分划分法,能够实现沥青组分相对含量的定性分析;综合该测试条件下的TG-DTG-DTA和XRD数据,采用任意内标法,以CaCO3作为内标物,能够快速、简便地实现对CA砂浆中Ca(OH)2和沥青含量的定量计算. 展开更多
关键词 CA砂浆 X射线衍射(xrd) 热重(TG) 微商热重(DTG) 差热分析(DTA) 任意内标法
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In situ observation of the phase transformation kinetics of bismuth during shock release
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作者 李江涛 王倩男 +7 位作者 徐亮 柳雷 张航 Sota Takagi Kouhei Ichiyanagi Ryo Fukaya Shunsuke Nozawa 胡建波 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期586-592,共7页
A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-... A time-resolved x-ray diffraction technique is employed to monitor the structural transformation of laser-shocked bismuth.Results reveal a retarded transformation from the shock-induced Bi-Ⅴphase to a metastable Bi-Ⅳphase during the shock release,instead of the thermodynamically stable Bi-Ⅲphase.The emergence of the metastable Bi-Ⅳphase is understood by the competitive interplay between two transformation pathways towards the Bi-Ⅳand Bi-Ⅲ,respectively.The former is more rapid than the latter because the Bi-Ⅴto B-Ⅳtransformation is driven by interaction between the closest atoms while the Bi-Ⅴto B-Ⅲtransformation requires interaction between the second-closest atoms.The nucleation time for the Bi-Ⅴto Bi-Ⅳtransformation is determined to be 5.1±0.9 ns according to a classical nucleation model.This observation demonstrates the importance of the formation of the transient metastable phases,which can change the phase transformation pathway in a dynamic process. 展开更多
关键词 phase transformation time-resolved x-ray diffraction(xrd) BISMUTH metastable phase nonequilibrium phase diagram
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Understanding the influence of petrographic parameters on strength of differently sized shale specimens using XRD and SEM 被引量:6
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作者 Debashis Das Brijes Mishra Neel Gupta 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2021年第5期953-961,共9页
Ground failure is a major contributor to fatalities in underground mines in the US.Underground coal mines in the Northern Appalachian have weak roof rock composed of shale,which is prone to failure under high horizont... Ground failure is a major contributor to fatalities in underground mines in the US.Underground coal mines in the Northern Appalachian have weak roof rock composed of shale,which is prone to failure under high horizontal stress.Understanding the relationship among strength,specimen size and rock petrographic parameters is essential for developing an effective ground control plan.Size effect studies have found that rock strength varies with specimen size.This paper attempts to understand this strength variation using three specimen sizes(254-mm,508-mm,and 762-mm).The specimen strength was measured and the major petrographic parameters affecting the strength,namely grain size,grain shape,quartz content,clay content,etc.were analyzed using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The petrographic parameters were then correlated with the strength of the three differently sized specimens.The results showed that 508-mm specimen had the lowest strength.Quartz content of the 508-mm specimen was lower than that of 254-mm and 762-mm specimens.Clay content and average grain size of the 508-mm specimen were higher than those of 254-mm and 762-mm specimens.These results clearly show that grain size,quartz content and clay content contribute to strength variation observed in differently sized shale specimens. 展开更多
关键词 Shale strength xrd(x-ray diffraction) SEM(scanning electron microscopy) Grain size Quartz content Grain shape
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X-ray Peak-Shift Determination of Deformation Fault Probability in Fe-Mn-Si Alloys 被引量:4
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作者 YonghuaRONG GangHE +2 位作者 ZhenghongGUO ShipuCHEN T.Y.Hsu(XUZuyao) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第5期459-461,共3页
The X-ray diffraction peak-shift method was introduced into the determination of deformation fault probability (a) of Fe-Mn-Si alloys with various Mn contents and thermomechanical cycling numbers. The precise lattice ... The X-ray diffraction peak-shift method was introduced into the determination of deformation fault probability (a) of Fe-Mn-Si alloys with various Mn contents and thermomechanical cycling numbers. The precise lattice constants required were obtained by numerical calculation instead of using standard sample without any fault. The influence of internal stress on the determined a has been evaluated, and the caused relative error was determined as about 4% and thus negligible. The results show that the deformation fault probability increases with decreasing Mn-content and increasing cycle number, which are qualitatively consistent with those results of Psf determined by peak-broadening method. 展开更多
关键词 x-ray diffraction Peak-shift method Deformation fault probability Fe-Mn-Si alloy
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A New Method for Clay Mineral Analysis and Its Application in Geology 被引量:3
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作者 王河锦 鲁安怀 陈涛 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2002年第4期429-436,共8页
X-ray diffraction (XRD) peaks in a low-angle diffraction section of clayminerals, especially those of authigenic origin, have broadening and tailing features in shape.Using the five basic parameters, peak position, pe... X-ray diffraction (XRD) peaks in a low-angle diffraction section of clayminerals, especially those of authigenic origin, have broadening and tailing features in shape.Using the five basic parameters, peak position, peak height, width, shape coefficient and asymmetry,to describe an XRD peak is more accurate, comprehensive and integrated than using only 3 of them,position, height and width. Following the concept of the five basic parameters of an XRD peak, theprogram Decoform proposed in this study provides more information in mineralogical analyses byfitting actual XRD profiles. In combination with the HW-IR plot, Decoform can he systematically andaccurately used in the comprehensive analyses of crystallinity, domain size, lattice strain andquantitative phase. It is also of value for the geological investigations of diagenesis,metamorphism, basin maturity, structural stress field and so on. 展开更多
关键词 clay minerals x-ray diffraction analysis xrd peak fitting CRYSTALLINITY domain size lattice strain quantitative analysis application in geology
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