Archean to Cenozoic mafic volcanic rocks from the North China craton are studied. They show Archean Proterozoic (Ar Pt) boundary and geochemical anomalies in Cenozoic basalts. Proterozoic mafic volcanics are enriche...Archean to Cenozoic mafic volcanic rocks from the North China craton are studied. They show Archean Proterozoic (Ar Pt) boundary and geochemical anomalies in Cenozoic basalts. Proterozoic mafic volcanics are enriched in most of the high field strength elements (HFSE) compared with Archean ones. Nb, Ta and Th show a distinct sequence of incompatibility in Archean and Proterozoic. The Cenozoic basalts are enriched in HFSE and Ni and their REEs are strongly differentiated with positive Eu anomalies ( δ (Eu)=1.14). The Ar Pt boundary could be related to change in oxygen fugacity and requires an increasing importance of enriched mantle source. The geochemistry of Cenozoic basalts implies a mantle source similar to OIB. Residuum from subducting partial melting of old basaltic oceanic crust and continental crust is likely to contribute to the formation of the enriched mantle.展开更多
The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD）...The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.展开更多
7 T MRI可以显著提高膝关节成像的信噪比及空间分辨率,能够进行超高分辨率成像和功能代谢成像。其通过测定骨、关节软骨、半月板及韧带内的不同成分,可以很好地评估骨质疏松的程度,更早地发现关节软骨和半月板的损伤以及评估损伤修复后...7 T MRI可以显著提高膝关节成像的信噪比及空间分辨率,能够进行超高分辨率成像和功能代谢成像。其通过测定骨、关节软骨、半月板及韧带内的不同成分,可以很好地评估骨质疏松的程度,更早地发现关节软骨和半月板的损伤以及评估损伤修复后的表现,为骨质疏松、骨性关节炎以及半月板损伤的早期诊断与治疗提供有力的依据。就7 T MRI在膝关节病变中的研究进展进行综述。展开更多
目的分析高场强磁共振成像(high field strength magnetic resonance imaging,MRI)对前列腺良恶性病变的鉴别诊断价值。方法选取2016年1月—2021年12月盐城市第三人民医院影像科收治的疑似前列腺病变患者60例,均以高场强MRI检查,以手术...目的分析高场强磁共振成像(high field strength magnetic resonance imaging,MRI)对前列腺良恶性病变的鉴别诊断价值。方法选取2016年1月—2021年12月盐城市第三人民医院影像科收治的疑似前列腺病变患者60例,均以高场强MRI检查,以手术穿刺活检病理诊断结果为金标准,分析高场强MRI诊断效能及影像学特征。结果手术病理确诊30例为良性前列腺增生(阴性)、30例为前列腺癌(阳性)。高场强MRI诊断准确度为95.00%,敏感度为93.33%,特异度为96.67%,阳性预测值为96.55%,阴性预测值为93.55%。经一致性系数分析,高场强与MRI诊断一致性为0.900,一致性良好。前列腺增生:前列腺体积弥漫性增大,T_(2)WI显示前列腺中央叶明显增大,信号不均匀,呈类圆形高信号/低信号,外周带受压变窄。前列腺癌:癌组织呈弥漫性浸润性生长,T_(2)WI移行带呈低信号,边界模糊,病变位于包膜内或突破包膜、侵犯精囊腺或血管神经束,或合并淋巴结肿大、骨盆骨转移。结论高场强MRI在前列腺良恶性病变鉴别诊断中的准确性和可靠性较高,具有推广应用价值。展开更多
Accurate calculation results of roll temperature are the key factors in rolling cooling and lubricating technology during the single-stand reversing cold rolling process. By combining the high-strength steel rolling e...Accurate calculation results of roll temperature are the key factors in rolling cooling and lubricating technology during the single-stand reversing cold rolling process. By combining the high-strength steel rolling experiments ,the numerical simulation of roll temperature, and the influence factors in reversing cold rolling were studied. The research results correspond with those of rolling experiments and show that the research method could provide effective instruction for roll cooling and emulsion flow rate control during the on-site rolling process.展开更多
文摘Archean to Cenozoic mafic volcanic rocks from the North China craton are studied. They show Archean Proterozoic (Ar Pt) boundary and geochemical anomalies in Cenozoic basalts. Proterozoic mafic volcanics are enriched in most of the high field strength elements (HFSE) compared with Archean ones. Nb, Ta and Th show a distinct sequence of incompatibility in Archean and Proterozoic. The Cenozoic basalts are enriched in HFSE and Ni and their REEs are strongly differentiated with positive Eu anomalies ( δ (Eu)=1.14). The Ar Pt boundary could be related to change in oxygen fugacity and requires an increasing importance of enriched mantle source. The geochemistry of Cenozoic basalts implies a mantle source similar to OIB. Residuum from subducting partial melting of old basaltic oceanic crust and continental crust is likely to contribute to the formation of the enriched mantle.
基金Funded by the Construction of Key Disciplines for Young Teacher Science Foundation of the Southwest Petroleum University(No.P209)the Research Fund for the Doctoral Program of Higher Education(No.20105121120002)the National Natural Science Foundation of China(Nos.51004084 and 51374177)
文摘The effects of plastic deformation and H2 S on fracture toughness of high strength casing steel（C110 steel） were investigated. The studied casing specimens are as follows： original casing, plastic deformation（PD） casing and PD casing after being immersed in NACE A solution saturated with H2S（PD＋H2S）. Instrumented impact method was employed to evaluate the impact behaviors of the specimens, meanwhile, dynamic fracture toughness（JId） was calculated by using Rice model and Schindler model. The experimental results show that dynamic fracture toughness of the casing decreases after plastic deformation. Compared with that of the original casing and PD casing, the dynamic fracture toughness decreases further when the PD casing immersed in H2 S, moreover, there are ridge-shaped feature and many secondary cracks present on the fracture surface of the specimens. Impact fracture mechanism of the casing is proposed as follows： the plastic deformation results in the increase of defect density of materials where the atomic hydrogen can accumulate in reversible or irreversible traps and even recombine to form molecular hydrogen, subsequently, the casing material toughness decreases greatly.
文摘7 T MRI可以显著提高膝关节成像的信噪比及空间分辨率,能够进行超高分辨率成像和功能代谢成像。其通过测定骨、关节软骨、半月板及韧带内的不同成分,可以很好地评估骨质疏松的程度,更早地发现关节软骨和半月板的损伤以及评估损伤修复后的表现,为骨质疏松、骨性关节炎以及半月板损伤的早期诊断与治疗提供有力的依据。就7 T MRI在膝关节病变中的研究进展进行综述。
基金Project(2022JJ30583) supported by the Natural Science Foundation of Hunan Province,ChinaProject(21B0315) supported by the Natural Science Research Project of Hunan Education Department,ChinaProject(18ZDXK04) supported by the Civil Engineering Key Discipline Innovation Project of Changsha University of Science and Technology,China。
文摘目的分析高场强磁共振成像(high field strength magnetic resonance imaging,MRI)对前列腺良恶性病变的鉴别诊断价值。方法选取2016年1月—2021年12月盐城市第三人民医院影像科收治的疑似前列腺病变患者60例,均以高场强MRI检查,以手术穿刺活检病理诊断结果为金标准,分析高场强MRI诊断效能及影像学特征。结果手术病理确诊30例为良性前列腺增生(阴性)、30例为前列腺癌(阳性)。高场强MRI诊断准确度为95.00%,敏感度为93.33%,特异度为96.67%,阳性预测值为96.55%,阴性预测值为93.55%。经一致性系数分析,高场强与MRI诊断一致性为0.900,一致性良好。前列腺增生:前列腺体积弥漫性增大,T_(2)WI显示前列腺中央叶明显增大,信号不均匀,呈类圆形高信号/低信号,外周带受压变窄。前列腺癌:癌组织呈弥漫性浸润性生长,T_(2)WI移行带呈低信号,边界模糊,病变位于包膜内或突破包膜、侵犯精囊腺或血管神经束,或合并淋巴结肿大、骨盆骨转移。结论高场强MRI在前列腺良恶性病变鉴别诊断中的准确性和可靠性较高,具有推广应用价值。
文摘Accurate calculation results of roll temperature are the key factors in rolling cooling and lubricating technology during the single-stand reversing cold rolling process. By combining the high-strength steel rolling experiments ,the numerical simulation of roll temperature, and the influence factors in reversing cold rolling were studied. The research results correspond with those of rolling experiments and show that the research method could provide effective instruction for roll cooling and emulsion flow rate control during the on-site rolling process.
