利用Gleeble-1500D热模拟试验机对Cu-0.4%Mg合金在变形温度为500~850℃,应变速率为0.001~10 s^-1条件下进行热模拟试验,研究稀土元素Y对其热变形行为的影响。对热变形过程中的组织演变进行分析,测得Cu-0.4%Mg合金和Cu-0.4%Mg-0.15%Y合...利用Gleeble-1500D热模拟试验机对Cu-0.4%Mg合金在变形温度为500~850℃,应变速率为0.001~10 s^-1条件下进行热模拟试验,研究稀土元素Y对其热变形行为的影响。对热变形过程中的组织演变进行分析,测得Cu-0.4%Mg合金和Cu-0.4%Mg-0.15%Y合金的真应力-真应变曲线。通过线性回归分析,计算出热变激活能,建立本构方程。结果表明：稀土元素Y可以细化晶粒,抑制动态再结晶的发生,促进第二相析出,提高Cu-0.4%Mg合金的显微硬度;流变应力随温度的降低或应变速率的升高而增大,高温低应变速率更有利于动态再结晶;Y的加入使Cu-0.4%Mg合金在600℃,应变速率为0.001 s^-1热变形的峰值应力提高了约22%;Cu-0.4%Mg合金和Cu-0.4%Mg-0.15%Y合金的热变形激活能分别为255.210 k J/mol、345.372 k J/mol,提高了约35%。展开更多
Anthocyanins are important components in the peel of red pears and contribute to the appearance of the fruit.Melatonin application is known to affect anthocyanin biosynthesis,but the effect of preharvest melatonin app...Anthocyanins are important components in the peel of red pears and contribute to the appearance of the fruit.Melatonin application is known to affect anthocyanin biosynthesis,but the effect of preharvest melatonin application on fruit coloration remains largely unknown.The objective of this study was to determine the effects of preharvest melatonin application on pigmentation,phenolic compounds,and the expression of related genes in Nanhong pear(Pyrus ussuriensis).The applications were performed during the pre-color-change period by spraying 50 or 200μmol L^(-1)of melatonin on fruits.We found that treatment with melatonin had a significant effect on color development.The concentrations of anthocyanins and flavonols were enhanced by melatonin treatment,whereas hydroxycinnamate and flavanol concentrations were reduced.Quantitative real-time PCR analyses indicated that the transcription levels for most anthocyanin biosynthetic genes and anthocyanin-related transcription factors were induced by melatonin.Melatonin application also stimulated the expression of melatonin biosynthesis-related genes and consequently caused an increase in endogenous melatonin concentration.These results provide insights into melatonin-induced fruit coloration and will facilitate the application of exogenous melatonin in agriculture.展开更多
文摘利用Gleeble-1500D热模拟试验机对Cu-0.4%Mg合金在变形温度为500~850℃,应变速率为0.001~10 s^-1条件下进行热模拟试验,研究稀土元素Y对其热变形行为的影响。对热变形过程中的组织演变进行分析,测得Cu-0.4%Mg合金和Cu-0.4%Mg-0.15%Y合金的真应力-真应变曲线。通过线性回归分析,计算出热变激活能,建立本构方程。结果表明：稀土元素Y可以细化晶粒,抑制动态再结晶的发生,促进第二相析出,提高Cu-0.4%Mg合金的显微硬度;流变应力随温度的降低或应变速率的升高而增大,高温低应变速率更有利于动态再结晶;Y的加入使Cu-0.4%Mg合金在600℃,应变速率为0.001 s^-1热变形的峰值应力提高了约22%;Cu-0.4%Mg合金和Cu-0.4%Mg-0.15%Y合金的热变形激活能分别为255.210 k J/mol、345.372 k J/mol,提高了约35%。
基金This research was supported by the National Natural Science Foundation of China(31701865)the earmarked fund for the China Agriculture Research System(CARS-28)the Liaoning Provincial Natural Science Foundation of China(2019-MS-276).
文摘Anthocyanins are important components in the peel of red pears and contribute to the appearance of the fruit.Melatonin application is known to affect anthocyanin biosynthesis,but the effect of preharvest melatonin application on fruit coloration remains largely unknown.The objective of this study was to determine the effects of preharvest melatonin application on pigmentation,phenolic compounds,and the expression of related genes in Nanhong pear(Pyrus ussuriensis).The applications were performed during the pre-color-change period by spraying 50 or 200μmol L^(-1)of melatonin on fruits.We found that treatment with melatonin had a significant effect on color development.The concentrations of anthocyanins and flavonols were enhanced by melatonin treatment,whereas hydroxycinnamate and flavanol concentrations were reduced.Quantitative real-time PCR analyses indicated that the transcription levels for most anthocyanin biosynthetic genes and anthocyanin-related transcription factors were induced by melatonin.Melatonin application also stimulated the expression of melatonin biosynthesis-related genes and consequently caused an increase in endogenous melatonin concentration.These results provide insights into melatonin-induced fruit coloration and will facilitate the application of exogenous melatonin in agriculture.
