Based on the introductions of a type of diaphragm-through connection between concrete-filled square steel tubular columns (CFSSTCs) and H-shaped steel beams,a finite element model of the connection is developed and us...Based on the introductions of a type of diaphragm-through connection between concrete-filled square steel tubular columns (CFSSTCs) and H-shaped steel beams,a finite element model of the connection is developed and used to investigate the seismic behavior of the connection.The results of the finite element model are validated by a set of cyclic loading tests.The cyclic loading tests and the finite element analyses indicate that the failure mode of the suggested connections is plastic hinge at the beam with inelastic rotation angle exceeding 0.04 rad.The suggested connections have sufficient strength,plastic deformation and energy dissipation capacity to be used in composite moment frames as beam-to-column rigid connections.展开更多
Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular c...Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular columns. The analysis reveals that smaller axial load ratio can improve the shear bearing capacity and ductility while larger axial load ratio will decrease the shear behavior of the through-diaphragm connections. The parametric studies indicate that the axial load ratio should be limited to less than 0.4 and its influence should be considered in the analysis and design of such connections.展开更多
Fixed-bed operating experimental column conditions were studied to evaluate the performance of brick from Bangui Region (in Central African Republic), coated with iron oxyhydroxide (ferrihydrite) for the removal of ir...Fixed-bed operating experimental column conditions were studied to evaluate the performance of brick from Bangui Region (in Central African Republic), coated with iron oxyhydroxide (ferrihydrite) for the removal of iron(II) from aqueous solution. The prediction of theoretical breakthrough profiles using Bohart and Adams sorption model was employed to achieve characteristic parameters such as depth of exchange zone, time required for exchange zone to move vertically, moving rate for the exchange zone and adsorption capacity useful for fixed-bed column reactor was investigated under varying operating conditions. The effects of bed depth and flow rate on iron(II) adsorption were studied. Our finding revealed that the Brick from Bangui Region (in Central African Republic), coated with ferrihydrite was a very efficient media for the removal of Fe(II) ions from water. The experimental data showed that the depth and the moving rate (10.3 ± 0.6 cm) and (0.208 ± 0.006 cm/min) respectively of the exchange zone (adsorption zone) were independent of variability of the height of the adsorbent bed column, however the variations of the flow rate affect the moving rate of the exchange zone. The bed depth service time (BDST) model was used and permitted us to predict the service times of columns operated at various flow rates and bed depths and these predicted values were compared with the experimental values.展开更多
目的建立以基质外标法定量,通过式净化柱(EMR-Lipid)结合高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定生乳中加米霉素残留量的分析方法。方法样品经酸性乙腈提取后,由EMR...目的建立以基质外标法定量,通过式净化柱(EMR-Lipid)结合高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定生乳中加米霉素残留量的分析方法。方法样品经酸性乙腈提取后,由EMR-Lipid通过式净化柱净化,通过BEH C18色谱柱进行梯度洗脱,电喷雾正离子多反应模式进行检测,基质外标法定量。结果加米霉素在0.5~20.0 ng/mL质量浓度范围内呈现良好线性关系,线性相关系数大于0.99;检出限(limit of detection,LOD)为0.5μg/kg;定量限(limit of quantification,LOQ)为1.0μg/kg;加米霉素在生乳中表现为基质增强效应,经基质空白曲线校正后,加米霉素在不同添加浓度平均回收率为74.0%~77.0%,测定结果的相对标准偏差(relative standard deviation,RSD)为3.92%~4.57%。结论该方法准确、灵敏、稳定、简单易操作,可以用于生乳中加米霉素残留量快速测定及定量分析,为生乳中加米霉素残留监控提供技术支持。展开更多
基金Supported by National Natural Science Foundation of China(No.51268054)Natural Science Foundation of Tianjin(No.13JCQNJC07300)the foundation of Key Laboratory of Coast Civil Structure Safety(Tianjin University),Ministry of Education of China(No.2011-1)
文摘Based on the introductions of a type of diaphragm-through connection between concrete-filled square steel tubular columns (CFSSTCs) and H-shaped steel beams,a finite element model of the connection is developed and used to investigate the seismic behavior of the connection.The results of the finite element model are validated by a set of cyclic loading tests.The cyclic loading tests and the finite element analyses indicate that the failure mode of the suggested connections is plastic hinge at the beam with inelastic rotation angle exceeding 0.04 rad.The suggested connections have sufficient strength,plastic deformation and energy dissipation capacity to be used in composite moment frames as beam-to-column rigid connections.
基金Supported by the National Natural Science Foundation of China(No.51268054 and No.51468061)the Natural Science Foundation of Tianjin(No.13JCQNJC07300)Foundation of Xinjiang University(No.XY110137)
文摘Nonlinear finite element analysis and parametric studies were carried out to study the influence of axial load ratio on the shear behavior of the through-diaphragm connections of concrete-filled square steel tubular columns. The analysis reveals that smaller axial load ratio can improve the shear bearing capacity and ductility while larger axial load ratio will decrease the shear behavior of the through-diaphragm connections. The parametric studies indicate that the axial load ratio should be limited to less than 0.4 and its influence should be considered in the analysis and design of such connections.
文摘Fixed-bed operating experimental column conditions were studied to evaluate the performance of brick from Bangui Region (in Central African Republic), coated with iron oxyhydroxide (ferrihydrite) for the removal of iron(II) from aqueous solution. The prediction of theoretical breakthrough profiles using Bohart and Adams sorption model was employed to achieve characteristic parameters such as depth of exchange zone, time required for exchange zone to move vertically, moving rate for the exchange zone and adsorption capacity useful for fixed-bed column reactor was investigated under varying operating conditions. The effects of bed depth and flow rate on iron(II) adsorption were studied. Our finding revealed that the Brick from Bangui Region (in Central African Republic), coated with ferrihydrite was a very efficient media for the removal of Fe(II) ions from water. The experimental data showed that the depth and the moving rate (10.3 ± 0.6 cm) and (0.208 ± 0.006 cm/min) respectively of the exchange zone (adsorption zone) were independent of variability of the height of the adsorbent bed column, however the variations of the flow rate affect the moving rate of the exchange zone. The bed depth service time (BDST) model was used and permitted us to predict the service times of columns operated at various flow rates and bed depths and these predicted values were compared with the experimental values.
文摘目的建立以基质外标法定量,通过式净化柱(EMR-Lipid)结合高效液相色谱-串联质谱法(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)测定生乳中加米霉素残留量的分析方法。方法样品经酸性乙腈提取后,由EMR-Lipid通过式净化柱净化,通过BEH C18色谱柱进行梯度洗脱,电喷雾正离子多反应模式进行检测,基质外标法定量。结果加米霉素在0.5~20.0 ng/mL质量浓度范围内呈现良好线性关系,线性相关系数大于0.99;检出限(limit of detection,LOD)为0.5μg/kg;定量限(limit of quantification,LOQ)为1.0μg/kg;加米霉素在生乳中表现为基质增强效应,经基质空白曲线校正后,加米霉素在不同添加浓度平均回收率为74.0%~77.0%,测定结果的相对标准偏差(relative standard deviation,RSD)为3.92%~4.57%。结论该方法准确、灵敏、稳定、简单易操作,可以用于生乳中加米霉素残留量快速测定及定量分析,为生乳中加米霉素残留监控提供技术支持。
