Porcine circovirus type 2 (PCV2) is closely related to the postweaning multisystemic wasting syndrome (PMWS). In this study, the pig serum and tissue samples collected from different regions of Hangzhou District in Zh...Porcine circovirus type 2 (PCV2) is closely related to the postweaning multisystemic wasting syndrome (PMWS). In this study, the pig serum and tissue samples collected from different regions of Hangzhou District in Zhejiang Province of China between 2003 and 2005 were analyzed by enzyme-linked immunosorbent assay (ELISA) for PCV2 antibody and by polymerase chain reaction (PCR) for ORF2 gene. The results show that out of 1250 randomly collected serum samples, 500 sera (40%) were seropositive for PCV2. PCR results demonstrate that Hangzhou PCV2 with more than 50% Chinese PCV2 strains and French PCV2 formed Cluster A. Only one PCV2 from Hangzhou belonged to Cluster B with some other Chinese PCV2 and Netherlands’s isolates. Cluster C consisted of PCV2 isolates from China, US, Canada, UK and Germany. The results indicate that the PCV2 infection was widespread in Hangzhou.展开更多
In order to study the influence of crystal structure change due to implantation dose on the hardness and wear performance of 300M high-strength steel,samples were surface modified by Cr implantation with dosages of 5....In order to study the influence of crystal structure change due to implantation dose on the hardness and wear performance of 300M high-strength steel,samples were surface modified by Cr implantation with dosages of 5.0 × 10^16,1.5 × 10^17 and 3.0 × 10^17 ions/cm^2.X-ray diffraction method,which was already applied in studies on the microstructure of deformed and heat-treated materials,was used to study the crystal structure of the implanted steel,and the results were corrected with the hardness and wear performance.The solid solution strengthening effect and microstructure vary with increase in implantation dose.Owing to strong solid solution hardening of Cr,small average crystallite size and high dislocation density,the hardness and wear resistance of implanted steel with dose of 5.0 × 10^16 ions/cm^2 were found to be the highest compared with other samples.Moreover,although the crystal lite size of the implanted sample with dose of 3 × 10^17 ions/cm^2 was similar to that of substrate and the dislocation density was lower than that of the substrate,its higher hardness and lower specific wear rate were due to the solid solution hardening and perhaps Cr clusters reinforcement.展开更多
基金Project supported by the Foundation of Agricultural Development of Hangzhou City, China
文摘Porcine circovirus type 2 (PCV2) is closely related to the postweaning multisystemic wasting syndrome (PMWS). In this study, the pig serum and tissue samples collected from different regions of Hangzhou District in Zhejiang Province of China between 2003 and 2005 were analyzed by enzyme-linked immunosorbent assay (ELISA) for PCV2 antibody and by polymerase chain reaction (PCR) for ORF2 gene. The results show that out of 1250 randomly collected serum samples, 500 sera (40%) were seropositive for PCV2. PCR results demonstrate that Hangzhou PCV2 with more than 50% Chinese PCV2 strains and French PCV2 formed Cluster A. Only one PCV2 from Hangzhou belonged to Cluster B with some other Chinese PCV2 and Netherlands’s isolates. Cluster C consisted of PCV2 isolates from China, US, Canada, UK and Germany. The results indicate that the PCV2 infection was widespread in Hangzhou.
基金This project was supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,Chinathe Jiangsu Province Graduate Cultivation Innovative Project(Grant No.KYLX16_0347)+4 种基金Natural Science Foundation for Excellent Young Scientists of Jiangsu Province,China(Grant No.BK20180068)China Postdoctoral Science Foundation funded project,China(Grant No.2018M630555)the Fundamental Research Funds for the Central Universities,China(Grant No.NS2018039)the China Scholarship CouncilChina(Grant No.201706830071,awarded to Xiao-hu Chen for 1 year of study at the Department of Mechanical and Aerospace Engineering,Carleton University).The raw/processed data required to reproduce these findings cannot be shared at this time due to contractual issues.
文摘In order to study the influence of crystal structure change due to implantation dose on the hardness and wear performance of 300M high-strength steel,samples were surface modified by Cr implantation with dosages of 5.0 × 10^16,1.5 × 10^17 and 3.0 × 10^17 ions/cm^2.X-ray diffraction method,which was already applied in studies on the microstructure of deformed and heat-treated materials,was used to study the crystal structure of the implanted steel,and the results were corrected with the hardness and wear performance.The solid solution strengthening effect and microstructure vary with increase in implantation dose.Owing to strong solid solution hardening of Cr,small average crystallite size and high dislocation density,the hardness and wear resistance of implanted steel with dose of 5.0 × 10^16 ions/cm^2 were found to be the highest compared with other samples.Moreover,although the crystal lite size of the implanted sample with dose of 3 × 10^17 ions/cm^2 was similar to that of substrate and the dislocation density was lower than that of the substrate,its higher hardness and lower specific wear rate were due to the solid solution hardening and perhaps Cr clusters reinforcement.
