The application of reversible degenerative radical polymerization(RDRP)in the construction of polymer networks(PNs)provides a facile and convenient way to fabricate 3D objects with the ability to be posttransformed.Ho...The application of reversible degenerative radical polymerization(RDRP)in the construction of polymer networks(PNs)provides a facile and convenient way to fabricate 3D objects with the ability to be posttransformed.However,the polymerization mechanism mainly relies on chain-growth polymerization,which limits its wide application for various polymeric materials with different functionalities.展开更多
Conjugated polymers are attractive components of modern plastic electronics and photovoltaic devices.They are synthesized mainly through a step-growth polymerization(SGP)mechanism.However,due to the uncontrollable cha...Conjugated polymers are attractive components of modern plastic electronics and photovoltaic devices.They are synthesized mainly through a step-growth polymerization(SGP)mechanism.However,due to the uncontrollable characteristic of classical SGP,this effort leads to batch-to-batch variations in solubility,uncontrolled molecular weight,and broad polydispersity of the polymers obtained,thus,severely limiting their processing properties and performance.Here we demonstrate a general theoretical model of controlled SGP process by examining the possibility of the polymer chains further involvement in the SGP and how this correlated with their respective molecular weights.Subsequently,we proposed a practical method by which the SGP system was confined in nano-sized reactors.This method enabled the synthesis of a variety of polymers,having precisely controlled molecular weights with narrow polydispersity.We anticipate that this venture would exemplify a starting point for a more sophisticated molecular and structural design of functional polymers in widespread applications.展开更多
酸土脂环酸芽孢杆菌(Alicyclobacillus acidoterrestris)是引起橙汁劣变的主要微生物,为研究酸土脂环酸芽孢杆菌在橙汁中的生长规律,利用近红外光谱获取橙汁中酸土脂环酸芽孢杆菌含量的信息,采用标准化(autoscale)、多元散射校正(multip...酸土脂环酸芽孢杆菌(Alicyclobacillus acidoterrestris)是引起橙汁劣变的主要微生物,为研究酸土脂环酸芽孢杆菌在橙汁中的生长规律,利用近红外光谱获取橙汁中酸土脂环酸芽孢杆菌含量的信息,采用标准化(autoscale)、多元散射校正(multiplicative scatter correction,MSC)、标准正态变换(standard normal variate,SNV)、去趋势化(detrend)对光谱进行预处理,结合化学计量学,构建近红外光谱与酸土脂环酸芽孢杆菌含量预测模型。在此基础上,将近红外光谱转换为酸土脂环酸芽孢杆菌预测菌落数据,并采用“一步法”直接基于预测菌落数构建橙汁中酸土脂环酸芽孢杆菌的生长模型。结果表明,利用标准化进行光谱预处理建立的偏最小二乘(partial least squares,PLS)模型对橙汁中酸土脂环酸芽孢杆菌含量的预测效果相对较好,其预测决定系数(prediction determination coefficient,Rp2)与预测均方根误差(root mean square error of prediction,RMSEP)分别为0.733和0.242 lg CFU/mL,相对分析误差(relative percent deviation,RPD)为1.919。4种预测模型的均方误差(mean square error,MSE)介于0.0046~0.0300 lg CFU/mL之间;均方根误差(root mean square error,RMSE)介于为0.068~0.173 lg CFU/mL之间;赤池信息准则(akaike information criterion,AIC值)介于-66.383~-53.944之间,且Huang-full模型的3种指标相较更小,较适合描述橙汁中酸土脂环酸芽孢杆菌的生长。将近红外光谱获得预测菌落数构建的4种生长模型与平板计数法构建的生长模型分别进行相关性分析,发现4种模型的相关系数(r)均大于0.900,且Huang-full模型的拟合效果最优。所构建的模型通过准确因子(accuracy factor,Af)和偏差因子(bias factor,Bf)进行验证,证实模型均具有良好的可靠性。因此,利用近红外光谱分析结合适当的化学计量学方法描述酸土脂环酸芽孢杆菌生长预测是可行的。展开更多
基金This work was supported by the National Natural Science Foundation of China(No.22101196)the China Postdoctoral Science Foundation(No.2021M692348)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions and the Program of Innovative Research Team of Soochow University.
文摘The application of reversible degenerative radical polymerization(RDRP)in the construction of polymer networks(PNs)provides a facile and convenient way to fabricate 3D objects with the ability to be posttransformed.However,the polymerization mechanism mainly relies on chain-growth polymerization,which limits its wide application for various polymeric materials with different functionalities.
基金the financial support from the National Natural Science Foundation of China(grant no.21674035 and 21604086)。
文摘Conjugated polymers are attractive components of modern plastic electronics and photovoltaic devices.They are synthesized mainly through a step-growth polymerization(SGP)mechanism.However,due to the uncontrollable characteristic of classical SGP,this effort leads to batch-to-batch variations in solubility,uncontrolled molecular weight,and broad polydispersity of the polymers obtained,thus,severely limiting their processing properties and performance.Here we demonstrate a general theoretical model of controlled SGP process by examining the possibility of the polymer chains further involvement in the SGP and how this correlated with their respective molecular weights.Subsequently,we proposed a practical method by which the SGP system was confined in nano-sized reactors.This method enabled the synthesis of a variety of polymers,having precisely controlled molecular weights with narrow polydispersity.We anticipate that this venture would exemplify a starting point for a more sophisticated molecular and structural design of functional polymers in widespread applications.
文摘酸土脂环酸芽孢杆菌(Alicyclobacillus acidoterrestris)是引起橙汁劣变的主要微生物,为研究酸土脂环酸芽孢杆菌在橙汁中的生长规律,利用近红外光谱获取橙汁中酸土脂环酸芽孢杆菌含量的信息,采用标准化(autoscale)、多元散射校正(multiplicative scatter correction,MSC)、标准正态变换(standard normal variate,SNV)、去趋势化(detrend)对光谱进行预处理,结合化学计量学,构建近红外光谱与酸土脂环酸芽孢杆菌含量预测模型。在此基础上,将近红外光谱转换为酸土脂环酸芽孢杆菌预测菌落数据,并采用“一步法”直接基于预测菌落数构建橙汁中酸土脂环酸芽孢杆菌的生长模型。结果表明,利用标准化进行光谱预处理建立的偏最小二乘(partial least squares,PLS)模型对橙汁中酸土脂环酸芽孢杆菌含量的预测效果相对较好,其预测决定系数(prediction determination coefficient,Rp2)与预测均方根误差(root mean square error of prediction,RMSEP)分别为0.733和0.242 lg CFU/mL,相对分析误差(relative percent deviation,RPD)为1.919。4种预测模型的均方误差(mean square error,MSE)介于0.0046~0.0300 lg CFU/mL之间;均方根误差(root mean square error,RMSE)介于为0.068~0.173 lg CFU/mL之间;赤池信息准则(akaike information criterion,AIC值)介于-66.383~-53.944之间,且Huang-full模型的3种指标相较更小,较适合描述橙汁中酸土脂环酸芽孢杆菌的生长。将近红外光谱获得预测菌落数构建的4种生长模型与平板计数法构建的生长模型分别进行相关性分析,发现4种模型的相关系数(r)均大于0.900,且Huang-full模型的拟合效果最优。所构建的模型通过准确因子(accuracy factor,Af)和偏差因子(bias factor,Bf)进行验证,证实模型均具有良好的可靠性。因此,利用近红外光谱分析结合适当的化学计量学方法描述酸土脂环酸芽孢杆菌生长预测是可行的。
