In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was dep...In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was deposited onto NdFeB substrate firstly.And then the outmost AlN layer with a higher hardness was prepared with the nitrogen/argon mixture gas of the nitrogen partial pressure at 50%of the total pressure of 0.5 Pa and depositing time of 30,50 and 70 min,respectively.The denser outmost AlN layer was formed on the inner Al crystal layer.There is an occurrence of the interfacial reaction and metallurgy bonding in the interface layer between the coatings and NdFeB substrate.It has been found that the thickness of outmost AlN layer has a significant impact on corrosion resistance.For 50 min to deposit outmost AlN layer,AlN/Al coated NdFeB has the best corrosion resistance.展开更多
文摘【目的】为明确稻虾共作模式下土壤-农产品重金属污染状况。【方法】于2022年10月在安徽合肥某农场常规水稻田(conventional rice culture,CRC)和稻虾田(rice-crayfish system,RCS)研究区129个点位采集土壤、稻米和小龙虾样品,测定As、Hg、Cr、Cu、Ni、Zn、Cd和Pb的含量,并采用综合质量影响指数法(influence index of comprehensive quality,IICQ)评价土壤重金属的污染程度,同时基于人体健康风险结合蒙特卡洛模拟的方法对研究区农产品重金属的健康风险进行定量分析。【结果】常规水稻田和稻虾田土壤重金属平均含量均超过安徽省土壤元素背景值,且Cd和Hg超标严重。两种种植模式下土壤均属于清洁状态(IICQ≤1)。常规水稻田稻米中Cd富集系数最高,稻虾田稻米Hg的富集系数高于其他重金属。小龙虾中Hg超出《食品安全国家标准食品中污染物限量》(GB2762—2022)限值标准。从非致癌风险结果来看,两种稻米重金属综合非致癌风险均超过可接受水平,成人超过可接受限值1的概率为21.32%(CRC)和10.7%(RCS),儿童有100%(CRC)和99.9%(RCS)的概率超过可接受限值1。小龙虾中重金属含量较低,但儿童仍有66.43%的概率超过可接受限值1。从致癌风险结果来看,稻米致癌风险主要来自重金属Cd、As和Cr,As是小龙虾致癌风险的主要元素。两种种植模式下综合致癌风险均大于1.00×10^(-4),成人致癌风险值分别有99.85%(CRC)和98.62%(RCS)的概率超过1.00×10^(-4),儿童超过可接受限值1.00×10^(-4)的概率分别为100%。小龙虾成人和儿童分别有11.62%和98.82%的概率超过可接受限值1.00×10^(-4)。根据概率分布结果,稻虾田成人和儿童食用稻米的综合致癌风险概率低于常规水稻田。【结论】综上,稻虾共作模式不仅可有效降低土壤重金属的环境风险,还能减少农作物的人体健康风险,可降低居民通过食用稻米途径的重金属致癌风险。
基金Zhejiang Provincial Natural Science Foundation of China(Y4090178)Ningbo Natural Science Foundation of China(2011A610208)+1 种基金Advanced Coating and Film innovation team(2011B81001)Outstanding Talent Recruiting Program Dedicated to Academician Q.J.Xue"(2009A31004)from Ningbo municipal government
文摘In order to improve the corrosion resistance of NdFeB,AlN/Al dual protective coatings were prepared by DC magnetron sputtering in a home-made industrial apparatus.The inner Al layer with an excellent toughness was deposited onto NdFeB substrate firstly.And then the outmost AlN layer with a higher hardness was prepared with the nitrogen/argon mixture gas of the nitrogen partial pressure at 50%of the total pressure of 0.5 Pa and depositing time of 30,50 and 70 min,respectively.The denser outmost AlN layer was formed on the inner Al crystal layer.There is an occurrence of the interfacial reaction and metallurgy bonding in the interface layer between the coatings and NdFeB substrate.It has been found that the thickness of outmost AlN layer has a significant impact on corrosion resistance.For 50 min to deposit outmost AlN layer,AlN/Al coated NdFeB has the best corrosion resistance.
