The X-ray powder diffraction data of the compound GdAlSi was studied by means of X-ray diffraction technique and refined by Rietveld method. The compound GdAlSi has tetragonal α-ThSi_2-type structure, space group I4_...The X-ray powder diffraction data of the compound GdAlSi was studied by means of X-ray diffraction technique and refined by Rietveld method. The compound GdAlSi has tetragonal α-ThSi_2-type structure, space group I4_1/amd (No.141), Z=4, the lattice parameters a=041234 (1) nm, c=1.44202(1) nm. The Smith and Snyder figure of merit [5] F_N is F_ 30=2521(36). The R-factors of Rietveld refinement are R_p=0.098 and R_ wp=0.128. The X-ray powder diffraction data are given. The field dependence of the magnetization measured at room temperature and the temperature variation of the inverse magnetic susceptibility of the compound GdAlSi were also presented.展开更多
A new compound K6FeNb15O42 was prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The X-ray powder diffraction data of the title compound was measured. K6FeNb15 O42 crystallizes in ...A new compound K6FeNb15O42 was prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The X-ray powder diffraction data of the title compound was measured. K6FeNb15 O42 crystallizes in the hexagonal system with unit cell parameters, a = 9. 1320(4) A ,c = 12. 0670(9) A , and space group P63/mcm (193) , z = 1. The calculated and measured densities are 4. 489 g/cm3 and 4. 485 g. cm3, respectively.展开更多
A new compound K6FeNb15O42 u(?) prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The XRD data of the title compound was determined. K6FeNb15O42 crystallizes the hexagonal system w...A new compound K6FeNb15O42 u(?) prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The XRD data of the title compound was determined. K6FeNb15O42 crystallizes the hexagonal system with unit cell parameters a=9. 1320(4) A,c=12. 0670(9) A, and space group P63/mcm(193) , 2=1. The calculated and measured densities are 4. 489 g/ cm3 and 4. 485 g. cm3, respectively.展开更多
Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and ...Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.展开更多
オ-ray powder diffraction data and crystal structure of RE compound NdCoGe3 were studied by using X-ray powder diffraction and refined by the Rietveld profile fitting method. The compound has the tetragonal BaNiSn3typ...オ-ray powder diffraction data and crystal structure of RE compound NdCoGe3 were studied by using X-ray powder diffraction and refined by the Rietveld profile fitting method. The compound has the tetragonal BaNiSn3type structure, space group I4mm (No.107) a=0.42961(2) nm, c=098147(4) nm, V=0.018114 nm3, Z=2 and Dx=7.717 g·cm-3. The figure of merit FN for the powder data is F30=623 (0.0107, 45). Structure refinement was performed with 110 reflections and led to Rp=11.78% and Rwp=16.56%.展开更多
The thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 ℃. No phase transition was observed in the experimental t...The thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 ℃. No phase transition was observed in the experimental temperature range. Data for the unit-cell parameters and temperatures were fitted empirically resulting in the following thermal expansion coefficients： αa = 5.8（3） × 10^-5, αb = 5.8 （1）× 10^-5, αc = 5.2（1）× 10^-5, and αv = 7.4（1） × 10^-3 ℃ 1 in good agreement with a recent neutron powder diffraction study. On the other hand, the variation of the unit-cell angles α, β and γ of kyanite with increase in temperature is very complicated, and the agreement among all studies is poor. The thermal expansion data at ambient pressure reported here and the compression data at ambient temperature from the literature suggest that, for the kyanite lattice, the most and least thermally expandable directions correspond to the most and least compressible directions, respectively.展开更多
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
The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic wi...The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic with lattice parameters a=7.2044(1)A,b=7.6895(6)A,c=4.4772(4)A,space group Pna2_(1) and 4 formula units of GdNiSn in unit cell.The Smith and Snyder figure of index F_(30) for this compound is 35(0.015,59).展开更多
The aim of this study is to evaluate the ability of powder X-ray diffraction(PXRD)differential scanning calo-rimetry(DSC)and near infrared(NIR)spectroscopy to quantify two polymorphic forms(B,H)of nateglinide in binar...The aim of this study is to evaluate the ability of powder X-ray diffraction(PXRD)differential scanning calo-rimetry(DSC)and near infrared(NIR)spectroscopy to quantify two polymorphic forms(B,H)of nateglinide in binary powder mixtures.For this purpose,univariate and multivariate method are developed.The results show that PXRD(with PLS regression)provides a reliable determination of nateglinide samples(predicted accuracy of 89.1%),which is the best choice for quantification of nateglinide polymorphic mixtures in practice,while NIR spectroscopy is the least accurate(predicted accuracy of 79.6%)mainly due to the effect of sample inhomogeneity.Though a good linear relation and a high predicted accuracy(93.4%)for DSC are successfully obtained,it could not be a practical way for low-content quanti-fication in nateglinide polymorphic mixtures.展开更多
The crystal structure of [Co(NH3)5Br]Br2 has been determined ab initio from the conventional X-ray powder diffraction data. The approximate structure with all 7 indeyendent non-H atoms was solved by direct methods. Th...The crystal structure of [Co(NH3)5Br]Br2 has been determined ab initio from the conventional X-ray powder diffraction data. The approximate structure with all 7 indeyendent non-H atoms was solved by direct methods. The final orthorhombic unit-cell parameters after Rietveld refinement are: a=13.6927, b=10.7071, c=6.9400A, V=1017.47A3, F30=93(0.0075,43), M20=49, Z=4. Space group is Pnma. The structure agreement factors are: Rp=0.066,Rwp=0.090, RF=0.041, RB=0.042.展开更多
Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crys...Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crystal form. Unfortunately, it is usually found in a polymorphic mixture with form B. In this study, pure crystal forms of A and B were prepared and characterized by X-ray powder diffraction （XRPD）, Fourier transform infrared spectroscopy （FT-IR） and thermal analysis. An XRPD-based method for the quantitative determination of the amount of the flupirtine maleate polymorphs form A and form B was also established through a systematic optimization of instrumental parameters. The results of the analytical methodology validation showed that the XPRD method had a broad quantitative range of 0- 100% （w/w）, good linear relationship, with R2= 0.999, excellent repeatability and precision and low limits of detection （LoD） of 0.15% （w/w） and quantification （LoQ） of 0.5% （w/w）. The results also showed that the single-peak method was not as good as the whole pattern in reducing the influence of the preferred orientation, but this can be compensated for by a systematic optimization of instrumental parameters and validating the analytical methodology to reduce errors and obtain a good, repeatable, sensitive, and accurate method. This XRPD method can be used to analyze mixtures of flupirtine maleate polymorphs （forms A and B） quantitatively and control the quality of the bulk drug.展开更多
The ability to display and inspect powder diffraction data quickly and efficiently is a central part of the data analysis process. Whilst many computer programs are capable of displaying powder data, their focus is ty...The ability to display and inspect powder diffraction data quickly and efficiently is a central part of the data analysis process. Whilst many computer programs are capable of displaying powder data, their focus is typically on structure solution. The research proposes a lightweight powder diffraction visualization program with the capability of fast rendering to compare powder data sets. Based on the success of the earlier version and user requests, Jpowder has been extended to display powder diffraction datasets using stack plot, which options to use meta-data for crystallographic powder diffraction data in XML format. Such stack plots allows crystallographers to identify phase transitions in materials.展开更多
Tantalum nitride （TAN） compact with a Vickers hardness of 26 GPa is prepared by a high-pressure and high- temperature （HPHT） method. The crystal structure and atom occupations of WC-type TaN have been investigated...Tantalum nitride （TAN） compact with a Vickers hardness of 26 GPa is prepared by a high-pressure and high- temperature （HPHT） method. The crystal structure and atom occupations of WC-type TaN have been investigated by neutron powder diffraction, and the compressibility of WC-type TaN has been investigated by using in-situ high-pressure synchrotron x-ray diffraction. The third-order Birch-Murnaghan equation of state fitted to the x-ray diffraction pressure- volume （P-V） sets of data, collected up to 41 GPa, yields ambient pressure isothermal bulk moduli of B0 = 369（2） GPa with pressure derivatives of B~ = 4 for the WC-type TaN. The bulk modulus of WC-type TaN is not in good agreement with the previous result （Bo = 351 GPa）, which is close to the recent theoretical calculation result （Bo = 378 GPa）. An analysis of the experiment results shows that crystal structure of WC-type TaN can be viewed as alternate stacking of Ta and N layers along the c direction, and the covalent Ta-N bonds between Ta and N layers along the c axis in the crystal structure play an important role in the incompressibility and hardness of WC-type TaN.展开更多
In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figu...In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.展开更多
A new method for pattern identification and simulation of X-ray powder diffraction data is described, which can give definite phase composition of the unknown rapidly and correctly. The method is implemented in Micros...A new method for pattern identification and simulation of X-ray powder diffraction data is described, which can give definite phase composition of the unknown rapidly and correctly. The method is implemented in Microsoft Fortran 77 for the IBM PC/XT/AT personal computer or their compatibles.展开更多
I graduated from the Department of Chemistry, Xiamen University in 1955, majoring in physical chemistry. I went to the Institute of Metallurgy under the Soviet Academy of Sciences in 1956 as a Ph.D.candidate in thermo...I graduated from the Department of Chemistry, Xiamen University in 1955, majoring in physical chemistry. I went to the Institute of Metallurgy under the Soviet Academy of Sciences in 1956 as a Ph.D.candidate in thermochemistry and crystal chemistry of metal alloys,and got my Ph.D.degree in 1960.In the following 30 years, I did basic and applied research in interdisciplines,including crystal chemistry,materials science and solid state physics.My main achievements can be listed in two aspects as follows:展开更多
In order to accurately identify the rock, it is necessary to study the identification method of the rock. The rock identification method, the thin slice microscopic image technique, the electron probe analysis method ...In order to accurately identify the rock, it is necessary to study the identification method of the rock. The rock identification method, the thin slice microscopic image technique, the electron probe analysis method or the X-ray powder crystal diffraction method cannot accurately determine the rock. An X-ray powder diffraction method combined with thin-film microscopic image technique and rock identification method was proposed. The X-ray powder diffraction method was combined with the thin-film microscopic image technique to identify the rock, and the microscopic image technique was used to determine the rock. The particle size, structure, shape, mineral color and structure, determine the type of rock, and then determine the mineral and mineral content of the rock by X-ray powder diffraction method, name the rock, and complete the identification of the rock. The experimental results show that the X-ray powder diffraction method or the thin-film microscopic image technique can not accurately determine the rock and combine the X-ray powder diffraction method with the thin-film microscopic image technology to identify the rock. Improve the accuracy of rock identification results.展开更多
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
A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes ...A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes in the hexagonal system -with unit cell parameters a=9.0527(4) A,c=11.790(1) A,and space group P63/mcm(193),z=1. The calculated and measured densities are 5. 293 g/cm3 and 5.285 g/cm3, respectively.展开更多
文摘The X-ray powder diffraction data of the compound GdAlSi was studied by means of X-ray diffraction technique and refined by Rietveld method. The compound GdAlSi has tetragonal α-ThSi_2-type structure, space group I4_1/amd (No.141), Z=4, the lattice parameters a=041234 (1) nm, c=1.44202(1) nm. The Smith and Snyder figure of merit [5] F_N is F_ 30=2521(36). The R-factors of Rietveld refinement are R_p=0.098 and R_ wp=0.128. The X-ray powder diffraction data are given. The field dependence of the magnetization measured at room temperature and the temperature variation of the inverse magnetic susceptibility of the compound GdAlSi were also presented.
基金Fund by International Centre for Dlffractlon Data.
文摘A new compound K6FeNb15O42 was prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The X-ray powder diffraction data of the title compound was measured. K6FeNb15 O42 crystallizes in the hexagonal system with unit cell parameters, a = 9. 1320(4) A ,c = 12. 0670(9) A , and space group P63/mcm (193) , z = 1. The calculated and measured densities are 4. 489 g/cm3 and 4. 485 g. cm3, respectively.
文摘A new compound K6FeNb15O42 u(?) prepared for the first time by solid state reaction in K2O-Fe2O3-Nb2O5 ternary system. The XRD data of the title compound was determined. K6FeNb15O42 crystallizes the hexagonal system with unit cell parameters a=9. 1320(4) A,c=12. 0670(9) A, and space group P63/mcm(193) , 2=1. The calculated and measured densities are 4. 489 g/ cm3 and 4. 485 g. cm3, respectively.
基金supported by the Australian Research Council Linkage Project(No.LP200200717)co sponsored by Newmont Corporation(United States)and Vega Industries(India)+1 种基金the Powder Diffraction Beamline at the Australia’s Nuclear Science and Technology Organisation(No.PDR19870),Australiathe Centre for Microscopy and Microanalysis at the University of Queensland(No.1366),Australia。
文摘Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.
文摘オ-ray powder diffraction data and crystal structure of RE compound NdCoGe3 were studied by using X-ray powder diffraction and refined by the Rietveld profile fitting method. The compound has the tetragonal BaNiSn3type structure, space group I4mm (No.107) a=0.42961(2) nm, c=098147(4) nm, V=0.018114 nm3, Z=2 and Dx=7.717 g·cm-3. The figure of merit FN for the powder data is F30=623 (0.0107, 45). Structure refinement was performed with 110 reflections and led to Rp=11.78% and Rwp=16.56%.
基金financially supported by the Natural Science Foundation of China(Grant 40872033)the Fundamental Research Funds for the Central Universities(to XL)the Natural Sciences and Engineering Research Council of Canada(to MF)
文摘The thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 ℃. No phase transition was observed in the experimental temperature range. Data for the unit-cell parameters and temperatures were fitted empirically resulting in the following thermal expansion coefficients： αa = 5.8（3） × 10^-5, αb = 5.8 （1）× 10^-5, αc = 5.2（1）× 10^-5, and αv = 7.4（1） × 10^-3 ℃ 1 in good agreement with a recent neutron powder diffraction study. On the other hand, the variation of the unit-cell angles α, β and γ of kyanite with increase in temperature is very complicated, and the agreement among all studies is poor. The thermal expansion data at ambient pressure reported here and the compression data at ambient temperature from the literature suggest that, for the kyanite lattice, the most and least thermally expandable directions correspond to the most and least compressible directions, respectively.
基金JST PRESTO(grant number JPMJPR22Q4)(Japan)The Light Metal Educational Foundation,Inc.(Japan),and“Knowledge Hub Aichi”Aichi Prefectural Government(Japan)The synchrotron radiation experiments were performed at BL46XUof SPring-8with the approval of the Japan Synchrotron Radiation Research Institute(JASRI)(Proposal No.2021A1663,2022A1001and 2022A1798).
文摘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.
基金Supported by a Grant-in-Aid from the International Centre for Diffraction Data and the Natural Science Foundation of Guangxi Zhuang Autonomous Region。
文摘The compound GdNiSn has been studied by X-ray powder diffraction technique.The crystal structure and the X-ray diffraction data for this compound at room temperature are reported.The compound GdNiSn is orthorhombic with lattice parameters a=7.2044(1)A,b=7.6895(6)A,c=4.4772(4)A,space group Pna2_(1) and 4 formula units of GdNiSn in unit cell.The Smith and Snyder figure of index F_(30) for this compound is 35(0.015,59).
基金Supported by Jiangsu Large Scientific Instruments Shared Services Platform Foundation(BZ201403)
文摘The aim of this study is to evaluate the ability of powder X-ray diffraction(PXRD)differential scanning calo-rimetry(DSC)and near infrared(NIR)spectroscopy to quantify two polymorphic forms(B,H)of nateglinide in binary powder mixtures.For this purpose,univariate and multivariate method are developed.The results show that PXRD(with PLS regression)provides a reliable determination of nateglinide samples(predicted accuracy of 89.1%),which is the best choice for quantification of nateglinide polymorphic mixtures in practice,while NIR spectroscopy is the least accurate(predicted accuracy of 79.6%)mainly due to the effect of sample inhomogeneity.Though a good linear relation and a high predicted accuracy(93.4%)for DSC are successfully obtained,it could not be a practical way for low-content quanti-fication in nateglinide polymorphic mixtures.
文摘The crystal structure of [Co(NH3)5Br]Br2 has been determined ab initio from the conventional X-ray powder diffraction data. The approximate structure with all 7 indeyendent non-H atoms was solved by direct methods. The final orthorhombic unit-cell parameters after Rietveld refinement are: a=13.6927, b=10.7071, c=6.9400A, V=1017.47A3, F30=93(0.0075,43), M20=49, Z=4. Space group is Pnma. The structure agreement factors are: Rp=0.066,Rwp=0.090, RF=0.041, RB=0.042.
基金supported by the Major Program of Ministry of Science and Technology of China(No:2015ZX09J15104-003002)
文摘Flupirtine maleate, a pharmaceutical compound for treating psychotic disease in clinics, has seven polymorphs. Form A, with better crystal stability and bioavailability, has been widely used as the pharmaceutical crystal form. Unfortunately, it is usually found in a polymorphic mixture with form B. In this study, pure crystal forms of A and B were prepared and characterized by X-ray powder diffraction （XRPD）, Fourier transform infrared spectroscopy （FT-IR） and thermal analysis. An XRPD-based method for the quantitative determination of the amount of the flupirtine maleate polymorphs form A and form B was also established through a systematic optimization of instrumental parameters. The results of the analytical methodology validation showed that the XPRD method had a broad quantitative range of 0- 100% （w/w）, good linear relationship, with R2= 0.999, excellent repeatability and precision and low limits of detection （LoD） of 0.15% （w/w） and quantification （LoQ） of 0.5% （w/w）. The results also showed that the single-peak method was not as good as the whole pattern in reducing the influence of the preferred orientation, but this can be compensated for by a systematic optimization of instrumental parameters and validating the analytical methodology to reduce errors and obtain a good, repeatable, sensitive, and accurate method. This XRPD method can be used to analyze mixtures of flupirtine maleate polymorphs （forms A and B） quantitatively and control the quality of the bulk drug.
文摘The ability to display and inspect powder diffraction data quickly and efficiently is a central part of the data analysis process. Whilst many computer programs are capable of displaying powder data, their focus is typically on structure solution. The research proposes a lightweight powder diffraction visualization program with the capability of fast rendering to compare powder data sets. Based on the success of the earlier version and user requests, Jpowder has been extended to display powder diffraction datasets using stack plot, which options to use meta-data for crystallographic powder diffraction data in XML format. Such stack plots allows crystallographers to identify phase transitions in materials.
基金Project supported by the Research Foundation of Key Laboratory of Neutron Physics(Grant No.2015BB03)the National Natural Science Foundation of China(Grant Nos.11774247)+2 种基金the Science Foundation for Excellent Youth Scholars of Sichuan University(Grant No.2015SCU04A04)the Joint Usage/Research Center PRIUS(Ehime University,Japan)Chinese Academy of Sciences(Grant No.2017-BEPC-PT-000568)
文摘Tantalum nitride （TAN） compact with a Vickers hardness of 26 GPa is prepared by a high-pressure and high- temperature （HPHT） method. The crystal structure and atom occupations of WC-type TaN have been investigated by neutron powder diffraction, and the compressibility of WC-type TaN has been investigated by using in-situ high-pressure synchrotron x-ray diffraction. The third-order Birch-Murnaghan equation of state fitted to the x-ray diffraction pressure- volume （P-V） sets of data, collected up to 41 GPa, yields ambient pressure isothermal bulk moduli of B0 = 369（2） GPa with pressure derivatives of B~ = 4 for the WC-type TaN. The bulk modulus of WC-type TaN is not in good agreement with the previous result （Bo = 351 GPa）, which is close to the recent theoretical calculation result （Bo = 378 GPa）. An analysis of the experiment results shows that crystal structure of WC-type TaN can be viewed as alternate stacking of Ta and N layers along the c direction, and the covalent Ta-N bonds between Ta and N layers along the c axis in the crystal structure play an important role in the incompressibility and hardness of WC-type TaN.
文摘In cooperation with figure-of-merits the Rietveld analysis can appraise both angular and intensity data of powder diffraction. In this work, X-ray diffraction pattern of Bi4(SiO4)3 was redetermined with intensity figure-of-merits, which qualify agreement between observed and calculated relative intensities. F30 is 158.90 (0.0059, 32), intensity figure of merit Rint is 8.7, I20(17), 8.0. The values of figure-of-merits show that the data of JCPDS cards are distorted. Both the experimental and calculated peak positions and heights are listed in detail.
文摘A new method for pattern identification and simulation of X-ray powder diffraction data is described, which can give definite phase composition of the unknown rapidly and correctly. The method is implemented in Microsoft Fortran 77 for the IBM PC/XT/AT personal computer or their compatibles.
文摘I graduated from the Department of Chemistry, Xiamen University in 1955, majoring in physical chemistry. I went to the Institute of Metallurgy under the Soviet Academy of Sciences in 1956 as a Ph.D.candidate in thermochemistry and crystal chemistry of metal alloys,and got my Ph.D.degree in 1960.In the following 30 years, I did basic and applied research in interdisciplines,including crystal chemistry,materials science and solid state physics.My main achievements can be listed in two aspects as follows:
文摘In order to accurately identify the rock, it is necessary to study the identification method of the rock. The rock identification method, the thin slice microscopic image technique, the electron probe analysis method or the X-ray powder crystal diffraction method cannot accurately determine the rock. An X-ray powder diffraction method combined with thin-film microscopic image technique and rock identification method was proposed. The X-ray powder diffraction method was combined with the thin-film microscopic image technique to identify the rock, and the microscopic image technique was used to determine the rock. The particle size, structure, shape, mineral color and structure, determine the type of rock, and then determine the mineral and mineral content of the rock by X-ray powder diffraction method, name the rock, and complete the identification of the rock. The experimental results show that the X-ray powder diffraction method or the thin-film microscopic image technique can not accurately determine the rock and combine the X-ray powder diffraction method with the thin-film microscopic image technology to identify the rock. Improve the accuracy of rock identification results.
基金supported by National Natural Science Foundation of China (Grant No. 50864002)Guangxi Provincial Natural Science Foundation of China (Grant No. 0991001)
文摘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.
基金Fund by International Centre for diffraction Data.
文摘A new compound Ba6Ti7Nb9O42 was prepared for the first time by solid state reaction in BaO-TiO2-Nb2O5, ternary system. The X-ray powder diffraction data of the title compound was determined. Ba6Ti7Nb9O42 crystallizes in the hexagonal system -with unit cell parameters a=9.0527(4) A,c=11.790(1) A,and space group P63/mcm(193),z=1. The calculated and measured densities are 5. 293 g/cm3 and 5.285 g/cm3, respectively.
