The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissim...The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissimilar materials.As an emerging technology,Flush Self⁃Piercing Riveting(FSPR)is still in the experimental phase and undergoing small batch equipment verification.This paper focuses on the joining methods for DCAA and TFSS in BIW,investigating the joining mechanisms,technical features,and forming principles of FSPR for steel/Al dissimilar materials with two⁃layer or three⁃layer plate combinations.Considering the TL4225/C611/CR5 sheet combination as a subject,the forming mechanism of high⁃quality joints was studied,and a physical and mathematical model was established to depict the relationship between the filling amount of the arc⁃gap and die dimensions,as well as the extrusion amount.This model effectively illustrates the relationship between the filling amount of the flowing metal in the arc⁃gap and critical parameters,such as die dimensions and feeding amounts.By simplifying the process of selecting joining parameters,it significantly reduces both the time and experimental workload associated with parameter selection.This provides a technical foundation for the application of DAAA and TFSS parts in BIW,enabling the rapid choice of appropriate joining parameters to meet the requirements for obtaining high⁃quality joints.The model can be effectively utilized to investigate the relationships between key parameters,including arc⁃gap radius,plate thickness,rivet arc radius,nail head radius,groove width,and feeding amount,while keeping other parameters constant.This approach provides a theoretical foundation for the design of Friction Stir Processing(FSP)joints and aids in the selection of optimal parameters.展开更多
目的:建立一种多思梯度淋洗技术测试消毒副产物卤代乙酸的方法。方法:采用Metrohm 850型离子色谱仪,METROSEP A Supp 7250分离柱;淋洗液A:18 mM Na2CO3的超纯水溶液;淋洗液B:超纯水;进样体积100μl,流速0.7 ml/min,测定废水样品中常规...目的:建立一种多思梯度淋洗技术测试消毒副产物卤代乙酸的方法。方法:采用Metrohm 850型离子色谱仪,METROSEP A Supp 7250分离柱;淋洗液A:18 mM Na2CO3的超纯水溶液;淋洗液B:超纯水;进样体积100μl,流速0.7 ml/min,测定废水样品中常规阴离子及二氯乙酸(DCAA)、三氯乙酸(TCAA)。结果:该方法相关性好(r>0.9999),线性范围宽,精密度高(RSD<1.5%),方法测量结果好,准确度高,分析时间短,一次进样可以分析多个阴离子及卤代乙酸,重现性好。结论:该方法是一种检测水中消毒副产物的理想方法。展开更多
The photocatalysts TaOxNy were prepared by gas-solid reaction method with Ta2O5 as starting substance nitrified by NH3 under high temperature.The prepared samples were characterized by XRD,XPS,and UV-VIS.The results o...The photocatalysts TaOxNy were prepared by gas-solid reaction method with Ta2O5 as starting substance nitrified by NH3 under high temperature.The prepared samples were characterized by XRD,XPS,and UV-VIS.The results of XRD and XPS showed that non-stoichiometric sample,TaO1.3N0.8,was formed when the reaction temperature was 850℃,the reaction time was 10 hours and the flux of ammonia gas was 100 mL/min.And the result of UV-VIS showed that the response area of the sample was shifted to the visible-light.In addition,the photocatalytic activities of TaOxNy for degradation of dichloroacetic acid(DCAA)under irradiation of visible light were also investigated in the paper.Furthermore,Pt/ TaOxNy was prepared by loading Pt on the surface of TaOxNy by photoreduction method.And the effect of depositing amount of Pt on degradation of DCAA were also discussed.The results showed that the photocatalytic activities of TaOxNy were highly increased by loading Pt on the surface of TaOxNy.The optimum loading amount of Pt was 1.5wt%.The degradation rate of DCAA was 51.06 % after irradiation for120 min under visible-light.展开更多
We studied the decomposition of two haloacetic acids (HAAs),dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA),in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation p...We studied the decomposition of two haloacetic acids (HAAs),dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA),in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV,H2O2/UV,O3 /H2O2,and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV,the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV,closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3-in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.展开更多
文摘The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissimilar materials.As an emerging technology,Flush Self⁃Piercing Riveting(FSPR)is still in the experimental phase and undergoing small batch equipment verification.This paper focuses on the joining methods for DCAA and TFSS in BIW,investigating the joining mechanisms,technical features,and forming principles of FSPR for steel/Al dissimilar materials with two⁃layer or three⁃layer plate combinations.Considering the TL4225/C611/CR5 sheet combination as a subject,the forming mechanism of high⁃quality joints was studied,and a physical and mathematical model was established to depict the relationship between the filling amount of the arc⁃gap and die dimensions,as well as the extrusion amount.This model effectively illustrates the relationship between the filling amount of the flowing metal in the arc⁃gap and critical parameters,such as die dimensions and feeding amounts.By simplifying the process of selecting joining parameters,it significantly reduces both the time and experimental workload associated with parameter selection.This provides a technical foundation for the application of DAAA and TFSS parts in BIW,enabling the rapid choice of appropriate joining parameters to meet the requirements for obtaining high⁃quality joints.The model can be effectively utilized to investigate the relationships between key parameters,including arc⁃gap radius,plate thickness,rivet arc radius,nail head radius,groove width,and feeding amount,while keeping other parameters constant.This approach provides a theoretical foundation for the design of Friction Stir Processing(FSP)joints and aids in the selection of optimal parameters.
文摘目的:建立一种多思梯度淋洗技术测试消毒副产物卤代乙酸的方法。方法:采用Metrohm 850型离子色谱仪,METROSEP A Supp 7250分离柱;淋洗液A:18 mM Na2CO3的超纯水溶液;淋洗液B:超纯水;进样体积100μl,流速0.7 ml/min,测定废水样品中常规阴离子及二氯乙酸(DCAA)、三氯乙酸(TCAA)。结果:该方法相关性好(r>0.9999),线性范围宽,精密度高(RSD<1.5%),方法测量结果好,准确度高,分析时间短,一次进样可以分析多个阴离子及卤代乙酸,重现性好。结论:该方法是一种检测水中消毒副产物的理想方法。
文摘The photocatalysts TaOxNy were prepared by gas-solid reaction method with Ta2O5 as starting substance nitrified by NH3 under high temperature.The prepared samples were characterized by XRD,XPS,and UV-VIS.The results of XRD and XPS showed that non-stoichiometric sample,TaO1.3N0.8,was formed when the reaction temperature was 850℃,the reaction time was 10 hours and the flux of ammonia gas was 100 mL/min.And the result of UV-VIS showed that the response area of the sample was shifted to the visible-light.In addition,the photocatalytic activities of TaOxNy for degradation of dichloroacetic acid(DCAA)under irradiation of visible light were also investigated in the paper.Furthermore,Pt/ TaOxNy was prepared by loading Pt on the surface of TaOxNy by photoreduction method.And the effect of depositing amount of Pt on degradation of DCAA were also discussed.The results showed that the photocatalytic activities of TaOxNy were highly increased by loading Pt on the surface of TaOxNy.The optimum loading amount of Pt was 1.5wt%.The degradation rate of DCAA was 51.06 % after irradiation for120 min under visible-light.
基金Natural Science Foundation of Chongqing under Grant No. CSTC2008BB7299.
文摘We studied the decomposition of two haloacetic acids (HAAs),dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA),in water by single oxidants ozone (O3) and ultraviolet radiation (UV) and the advanced oxidation processes (AOPs) constituted by the combinations of O3/UV,H2O2/UV,O3 /H2O2,and O3/H2O2/UV. The concentrations of HAAs were analyzed at specified time intervals to track their decomposition. Except for O3 and UV,the four combined oxidation processes remarkably enhance the decomposition of DCAA and TCAA owing to the generated very reactive hydroxyl radicals. The fastest decomposition process is O3/H2O2/UV,closely followed by O3/UV. DCAA is much easier to decompose than TCAA. The kinetics of HAA decomposition by O3/UV can be described well by a pseudo first-order reaction model under a constant initial dissolved O3 concentration and fixed UV radiation. Humic acids and HCO3-in the reaction system both decrease the decomposition rate constants for DCAA and TCAA. The amount of H2O2 accumulates in the presence of humic acids in the O3/UV process.
