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In order to improve the shortcomings of poor dispersibility, easy agglomeration and easy corrosion of flaky zinc powder in inorganic zinc-rich coatings, the surface of flaky zinc powder was modified by silane coupling agent KH560 and cerium nitrate, and the optimum process conditions for surface modification of zinc powder was screened by polarization curve test.The changes in physical properties and corrosion resistance of zinc powder on zinc-rich coatings before and after modification were compared.Results showed that the optimal modification conditions of silane coupling agent KH560 were 12%(mass fraction), 60 ℃ of reaction temperature, pH 8 and 60 min of reaction time.The optimum dosage of cerium nitrate modified zinc flake/zinc powder was 0.01%(mass fraction)under the process conditions of room temperature, pH 7 and 60 min of reaction time.The dispersibility of modified zinc powder in water was improved.Moreover, the workability, drying time and adhesion of the modified zinc powder changed significantly.The corrosion current of the coating prepared by modified zinc powder was reduced by about 1 order of magnitude, the polarization resistance was increased by about 1 order of magnitude, and the corrosion resistance of the coating was significantly improved.In general, the cerium nitrate modified coating had the lowest passivation current and the smallest corrosion rate, which could be recommended to use cerium nitrate modified zinc powder for long-term protection.a

Background: Type-specific high-risk HPV (hrHPV) infection is related to cervical carcinogenesis. The prevalence of hrHPV infection varies geographically, which might reflect the epidemiological characteristics of cervical cancer among different populations. To establish a foundation for HPV-based screening and vaccination programs in China, we investigated the most recent HPV prevalence and genotypic distributions in different female age groups and geographical regions in China. Methods: In 2012, a total of 120,772 liquid-based cytological samples from women enrolled for population- or employee-based cervical screening in 37 Chinese cities were obtained by the Laboratory of Molecular Infectious Diseases of Guangzhou KingMed. A total of 111,131 samples were tested by Hybrid Capture II and the other 9,641 were genotyped using the Tellgenplex™ HPV DNA Assay. Results: The total positive rate for hrHPV was 21.07 %, which ranged from 18.42 % (Nanchang) to 31.94 % (Haikou) and varied by region. The regions of Nanchang, Changsha, Hangzhou, Chengdu, Fuzhou, Guangdong, and Guiyang could be considered the low prevalence regions. Age-specific prevalence showed a "two-peak" pattern, with the youngest age group (15-19 years) presenting the highest hrHPV infection rate (30.55 %), followed by a second peak for the 50-60-year-old group. Overall, the most prevalent genotypes were HPV16 (4.82 %) and HPV52 (4.52 %), followed by HPV58 (2.74 %). Two genotypes HPV6 (4.01 %) and HPV11 (2.29 %) were predominant in the low-risk HPV (lrHPV) type, while the mixed genotypes HPV16 + 52 and HPV52 + 58 were most common in women with multiple infections. Conclusions: This study shows that HPV infection in China has increased to the level of an "HPV-heavy-burden" zone in certain regions, with prevalence varying significantly among different ages and regions. Data from this study represent the most current survey of the nationwide prevalence of HPV infection in China, and can serve as valuable reference to guide nationwide cervical cancer screening and HPV vaccination programs. [ABSTRACT FROM AUTHOR]