双相不锈钢2205在超低温或高温的环境下也能够保证材料足够的韧性与强度,满足管道、海工桥梁等特殊场合条件下的安全使用,但其材料晶粒粗大,采用超声波检测内部质量时存在散射和声速指向性差的问题,影响检测结果评判。为解决上述问题,...双相不锈钢2205在超低温或高温的环境下也能够保证材料足够的韧性与强度,满足管道、海工桥梁等特殊场合条件下的安全使用,但其材料晶粒粗大,采用超声波检测内部质量时存在散射和声速指向性差的问题,影响检测结果评判。为解决上述问题,提出脉冲反射式超声波采用双晶纵波斜探头和自制对比试块调校进行检测。结果表明:1)双相不锈钢2205材料粗晶粒和各向异性导致信噪比下降,波束指向性差;2)双晶纵波斜探头最高反射声压在探头焦距标称值的1/2位置,以最高反射声压两端降低6 d B作为有效检测区域;3)利用双晶纵波斜探头及自制对比试块进行检测,通过射线与碳刨2种方法进行对比分析,超声波检测误差不超过3 mm,此方法是可行的。展开更多
A 240-day feeding trial was conducted to investigate the effects of dietary vitamin C on growth performance,anti-oxidative response,and fatty acid composition of juvenile abalone Haliotis discus hannai Ino(initial bod...A 240-day feeding trial was conducted to investigate the effects of dietary vitamin C on growth performance,anti-oxidative response,and fatty acid composition of juvenile abalone Haliotis discus hannai Ino(initial body weight:0.93±0.00 g).Three semi-purified experimental diets were formulated containing 0.00,94.52,and 9649.58 mg/kg of vitamin C supplied as L-ascorbyl-2-monophosphate.The results show that there was no significant difference in weight gain ratio,daily increment in shell length,and survival rate among the three treatments.Adding dietary vitamin C(9649.58 mg/kg)significantly increased the activities of superoxide dismutase(SOD),glutathine peroxidase(GPX),glitathione-S-transferase(GST),glutathione reductase(GR),alkaline phosphatase(AKP),and lysozyme in viscera(P<0.05).In muscle,activities of phenoloxidase,catalase,SOD,GST,GR,and AKP were increased in the treatment with 9649.58 mg/kg of dietary vitamin C(P<0.05).The highest concentrations of ascorbic acid in viscera and muscle were found in the group with 9649.58 mg/kg of dietary vitamin C(P<0.05).The contents of crude protein and crude lipid in the soft body were significantly increased in the 9649.58 mg/kg group(P<0.05).Dietary vitamin C supplementation significantly decreased the contents of saturated fatty acids(14:0,16:0,and 18:0),and increased the composition of 18:2n-6 and 22:6n-3 in the soft body of abalone(P<0.05).Therefore,although there were no significant effects on the growth performance,dietary vitamin C supplementation improved the anti-oxidation and immune responses,increased specific unsaturated fatty acid(i.e.,16:1,18:1n-7,18:1n-9,18:2n-6 and 22:6n-3),and decreased specific saturated fatty acid(i.e.,14:0,16:0 and 18:0)contents in the soft body of abalone.展开更多
文摘双相不锈钢2205在超低温或高温的环境下也能够保证材料足够的韧性与强度,满足管道、海工桥梁等特殊场合条件下的安全使用,但其材料晶粒粗大,采用超声波检测内部质量时存在散射和声速指向性差的问题,影响检测结果评判。为解决上述问题,提出脉冲反射式超声波采用双晶纵波斜探头和自制对比试块调校进行检测。结果表明:1)双相不锈钢2205材料粗晶粒和各向异性导致信噪比下降,波束指向性差;2)双晶纵波斜探头最高反射声压在探头焦距标称值的1/2位置,以最高反射声压两端降低6 d B作为有效检测区域;3)利用双晶纵波斜探头及自制对比试块进行检测,通过射线与碳刨2种方法进行对比分析,超声波检测误差不超过3 mm,此方法是可行的。
基金Supported by the National Key R&D Program of China(No.2018YFD0900400)the Earmarked Fund for Modern Agro-industry Technology Research System(No.CARS-49)。
文摘A 240-day feeding trial was conducted to investigate the effects of dietary vitamin C on growth performance,anti-oxidative response,and fatty acid composition of juvenile abalone Haliotis discus hannai Ino(initial body weight:0.93±0.00 g).Three semi-purified experimental diets were formulated containing 0.00,94.52,and 9649.58 mg/kg of vitamin C supplied as L-ascorbyl-2-monophosphate.The results show that there was no significant difference in weight gain ratio,daily increment in shell length,and survival rate among the three treatments.Adding dietary vitamin C(9649.58 mg/kg)significantly increased the activities of superoxide dismutase(SOD),glutathine peroxidase(GPX),glitathione-S-transferase(GST),glutathione reductase(GR),alkaline phosphatase(AKP),and lysozyme in viscera(P<0.05).In muscle,activities of phenoloxidase,catalase,SOD,GST,GR,and AKP were increased in the treatment with 9649.58 mg/kg of dietary vitamin C(P<0.05).The highest concentrations of ascorbic acid in viscera and muscle were found in the group with 9649.58 mg/kg of dietary vitamin C(P<0.05).The contents of crude protein and crude lipid in the soft body were significantly increased in the 9649.58 mg/kg group(P<0.05).Dietary vitamin C supplementation significantly decreased the contents of saturated fatty acids(14:0,16:0,and 18:0),and increased the composition of 18:2n-6 and 22:6n-3 in the soft body of abalone(P<0.05).Therefore,although there were no significant effects on the growth performance,dietary vitamin C supplementation improved the anti-oxidation and immune responses,increased specific unsaturated fatty acid(i.e.,16:1,18:1n-7,18:1n-9,18:2n-6 and 22:6n-3),and decreased specific saturated fatty acid(i.e.,14:0,16:0 and 18:0)contents in the soft body of abalone.
