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Seamless flatness rollers are the core equipment for cold-rolled strip flatness detection. The change in wear resistance of the roller surface-strengthened layer has important guiding significance for the prediction of the roller surface life. The experimental results of the five rounds of friction and wear testing show that the volume–wear rate of the original roller surface is only 1.85 × 10−6 mm3 (N·M)−1. After the first grinding, the wear resistance of the roller surface decreased and the wear rate was approximately 2.76 × 10−6 mm3 (N·M)−1. After the second grinding, the wear morphology, wear rate and wear resistance of the samples in each round showed little difference. The average wear rate in the last three rounds of the test is 3.56 × 10−6 mm3 (N·M)−1 and the wear resistance is significantly lower than that of the previous two rounds of the test. The calculation shows that the original surface wear resistance is 32.92% higher than that of the surface after the first grinding, and the average wear resistance of the surface after the first grinding is 22.59% higher than that of the surface after the second, third and fourth grinding. With long-term use and repeated grinding repair, the roller surface will show a trend of wear resistance decline. When the wear resistance decreases to a certain degree, it will reach a stage of stability. These phenomena provide regular and quantitative references for the study of the life prediction of flatness meter rollers. [ABSTRACT FROM AUTHOR]

During the process of hot rolling, seam defects often appear on the edges of the interstitial‐free (IF) steel, which seriously affects product quality and yield. To this end, the macro‐ and micromorphology of edge seam defects are analyzed, their specific characteristics are summarized, and the defect cast slab rolling experiment is conducted. The experiment shows that the pore, crack, and slag inclusion are not the causes of the seam defects. Then, through a combination of theoretical analysis, actual parameters' detection, and experiments, the formation mechanisms of the seam defects are evidently side folding of the intermediate slab and flipping of the corner metal. The mechanisms of the two types of folds are also described in detail. Finally, in view of the mechanisms, the advantages and disadvantages of control measures are analyzed, and the concave anvil of the slab sizing press is selected at last. To determine the effectiveness of the scheme, a pass experiment is conducted on a slab sizing press at the production site. Results show that the steel coils without slab sizing press generally have seam defects, whereas the coils with a concave anvil slab sizing press do not. The defects are almost totally eliminated. [ABSTRACT FROM AUTHOR]

Borrelia burgdorferi as a causative agent of Lyme disease is transmitted by Ixodes spp. ticks to humans and animals. Sheep is considered a natural reservoir for B. burgdorferi and plays a pivotal role in disease transmission and the expansion of natural foci. An epidemiological investigation of B. burgdorferi in sheep is essential for prevention and control of Lyme disease. In this study, we developed a recombinant outer surface protein C (OspC)-based ELISA for serological study of B. burgdorferi in sheep with a specificity and sensitivity of 84.4% and 86.2%, respectively. A total of 972 collected serum samples from the Northeast China regions in 2015 and 2016 were determined with positive rates of 5.8% and 12.2%, respectively. Thus, specific pathogen-free sheep were infected with B. burgdorferi SZ strain to study on the secretion of specificity antibody against OspC. It revealed that specific antibody was detected on day 5 postinoculation and sustained in a high level for ∼28 days, the peak occurred at ∼13 days. Taken together, the result indicated that the established ELISA is capable for clinical diagnosis and epidemiological study on B. burgdorferi in sheep at the early stage of infection and detecting the specific antibody during the secretion period. [ABSTRACT FROM AUTHOR]

Borrelia burgdorferi as a causative agent of Lyme disease is transmitted by Ixodes spp. ticks to humans and animals. Sheep is considered a natural reservoir for B. burgdorferi and plays a pivotal role in disease transmission and the expansion of natural foci. An epidemiological investigation of B. burgdorferi in sheep is essential for prevention and control of Lyme disease. In this study, we developed a recombinant outer surface protein C (OspC)-based ELISA for serological study of B. burgdorferi in sheep with a specificity and sensitivity of 84.4% and 86.2%, respectively. A total of 972 collected serum samples from the Northeast China regions in 2015 and 2016 were determined with positive rates of 5.8% and 12.2%, respectively. Thus, specific pathogen-free sheep were infected with B. burgdorferi SZ strain to study on the secretion of specificity antibody against OspC. It revealed that specific antibody was detected on day 5 postinoculation and sustained in a high level for ∼28 days, the peak occurred at ∼13 days. Taken together, the result indicated that the established ELISA is capable for clinical diagnosis and epidemiological study on B. burgdorferi in sheep at the early stage of infection and detecting the specific antibody during the secretion period.