Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has at...Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes. Matrix effect related studies are especially important during in-situ U- Pb dating based on Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry （LA-MC- ICPMS）. However, to our knowledge, only few thorough and systematical matrix effect study of U-bearing oxide minerals has been reported. In this study, we systematically analyzed the matrix effect of U-bearing oxide minerals in order to take place the standards which are difficult to prepare with available standards.展开更多
Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in t...Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.展开更多
With an increased utilization of carbon fiber reinforced polymers(CFRPs)in high temperature environments,investigating their effects on materials becomes exceedingly important.This study presents a comparative investi...With an increased utilization of carbon fiber reinforced polymers(CFRPs)in high temperature environments,investigating their effects on materials becomes exceedingly important.This study presents a comparative investigation of thermo-oxidative aging effects on the flexural performance of two carbon fiber reinforced composite laminates(CFRCLs):a quasi-isotropic plain-woven CFRCL and a quasi-isotropic unidirectional layup CFRCL(designated as PW-CFRCL and UD-CFRCL,respectively).The CFRCLs were subjected to thermo-oxidative aging for specific durations,and their flexural strength was evaluated through three-point bending tests.The flexural strength of the laminates decreased with the prolonged aging duration.Despite having lower fiber content,PW-CFRCLs showed higher flexural strength than UD-CFRCLs.After eight days of aging,the flexural strength of PW-CFRCLs decreased by merely 4%-5%,while that of UD-CFRCLs decreased by 11%-14%.After 32 days of aging,the thinner PW-CFRCL with the lowest fiber content exhibited the highest flexural strength(595.52 MPa),followed by the thinner UD-CFRCL(549.83 MPa),then the thicker PW-CFRCL(445.29 MPa)and finally,the thicker UD-CFRCL(393.90 MPa).The decline in flexural properties of the laminates was primarily attributed to matrix cracking and interface debonding resulting from matrix oxidation.To validate the universality of this result,the finite element method was employed,showing a good correlation with the experimental findings.展开更多
Two types of alumina dispersion-strengthened copper（ADSC） alloys were fabricated by a novel in-situ reactive synthesis（IRS） and a traditional internal oxidation（IO） process. The features of alumina dispersoids i...Two types of alumina dispersion-strengthened copper（ADSC） alloys were fabricated by a novel in-situ reactive synthesis（IRS） and a traditional internal oxidation（IO） process. The features of alumina dispersoids in these ADSC alloys were investigated by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is found that nano-sized γ-Al2O3 particles of approximately 10 nm in diameter are homogeneously distributed in the IRS-ADSC composites. Meanwhile, larger-sized, mixed crystal structure alumina with rod-shaped morphology is embedded in the IO-ADSC alloy. The IRS-ADSC composites can obtain better mechanical and physical properties than the IO-ADSC composites; the tensile strength of the IRS-ADSC alloy can reach 570 MPa at room temperature, its electrical conductivity is 85% IACS, and the Rockwell hardness can reach 86 HRB.展开更多
基金financially supported by the National Natural Science Foundation of China(grants No.41503052 and 41373053)the National Science and Technology Infrastructure(grant No.DDK14-39)
文摘Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes. Matrix effect related studies are especially important during in-situ U- Pb dating based on Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry （LA-MC- ICPMS）. However, to our knowledge, only few thorough and systematical matrix effect study of U-bearing oxide minerals has been reported. In this study, we systematically analyzed the matrix effect of U-bearing oxide minerals in order to take place the standards which are difficult to prepare with available standards.
文摘Oxidation behavior of C/C-SiC gradient matrix composites and C/C composites were compared in stationary air. The results show that oxidation threshold of C-SiC materials increases with the amount of SiC particles in the codeposition matrix. Oxidation rate of C/C-SiC gradient matrix composites is significantly lower than that of C/C material. The micro-oxidation process was observed by SEM.
基金National Natural Science Foundation of China(No.12372130)。
文摘With an increased utilization of carbon fiber reinforced polymers(CFRPs)in high temperature environments,investigating their effects on materials becomes exceedingly important.This study presents a comparative investigation of thermo-oxidative aging effects on the flexural performance of two carbon fiber reinforced composite laminates(CFRCLs):a quasi-isotropic plain-woven CFRCL and a quasi-isotropic unidirectional layup CFRCL(designated as PW-CFRCL and UD-CFRCL,respectively).The CFRCLs were subjected to thermo-oxidative aging for specific durations,and their flexural strength was evaluated through three-point bending tests.The flexural strength of the laminates decreased with the prolonged aging duration.Despite having lower fiber content,PW-CFRCLs showed higher flexural strength than UD-CFRCLs.After eight days of aging,the flexural strength of PW-CFRCLs decreased by merely 4%-5%,while that of UD-CFRCLs decreased by 11%-14%.After 32 days of aging,the thinner PW-CFRCL with the lowest fiber content exhibited the highest flexural strength(595.52 MPa),followed by the thinner UD-CFRCL(549.83 MPa),then the thicker PW-CFRCL(445.29 MPa)and finally,the thicker UD-CFRCL(393.90 MPa).The decline in flexural properties of the laminates was primarily attributed to matrix cracking and interface debonding resulting from matrix oxidation.To validate the universality of this result,the finite element method was employed,showing a good correlation with the experimental findings.
基金financially supported by the National Natural Science Foundation of China(NO.51464013)the Dr.Initialization Fund of Jiangxi University of Science and Technology(No.jxxjbs14013)
文摘Two types of alumina dispersion-strengthened copper（ADSC） alloys were fabricated by a novel in-situ reactive synthesis（IRS） and a traditional internal oxidation（IO） process. The features of alumina dispersoids in these ADSC alloys were investigated by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is found that nano-sized γ-Al2O3 particles of approximately 10 nm in diameter are homogeneously distributed in the IRS-ADSC composites. Meanwhile, larger-sized, mixed crystal structure alumina with rod-shaped morphology is embedded in the IO-ADSC alloy. The IRS-ADSC composites can obtain better mechanical and physical properties than the IO-ADSC composites; the tensile strength of the IRS-ADSC alloy can reach 570 MPa at room temperature, its electrical conductivity is 85% IACS, and the Rockwell hardness can reach 86 HRB.
