为研究聚乙烯基三苯乙炔基硅烷树脂的热分解机理,利用TG-DTG技术探讨了聚乙烯基三苯乙炔基硅烷树脂的非等温热分解过程.借助非模型拟合法和模型拟合法分析了聚乙烯基三苯乙炔基硅烷树脂(PVTPES)的热分解行为,建立了动力学函数,得到了聚...为研究聚乙烯基三苯乙炔基硅烷树脂的热分解机理,利用TG-DTG技术探讨了聚乙烯基三苯乙炔基硅烷树脂的非等温热分解过程.借助非模型拟合法和模型拟合法分析了聚乙烯基三苯乙炔基硅烷树脂(PVTPES)的热分解行为,建立了动力学函数,得到了聚乙烯基三苯乙炔基硅烷树脂的热分解反应机理.结果表明,6种热分析方法计算得到PVTPES的热分解活化能(E)在240 k J/mol左右,指前因子lg A=15.51,机理符合三维(3D)扩散控制机理.聚合物PVTPES的热分解过程分析进一步证实芳炔单体的热聚合为环三聚反应.展开更多
运用TG-DTG技术研究了炔丙基改性酚醛树脂聚合物的非等温热分解过程,通过Kissinger法和FWO法获得聚合物分解的动力学参数,利用模型拟合法推测该聚合物的热分解机理,并用非模型拟合法对机理进行了验证。实验结果表明,该聚合物的Td5分解...运用TG-DTG技术研究了炔丙基改性酚醛树脂聚合物的非等温热分解过程,通过Kissinger法和FWO法获得聚合物分解的动力学参数,利用模型拟合法推测该聚合物的热分解机理,并用非模型拟合法对机理进行了验证。实验结果表明,该聚合物的Td5分解温度在390℃左右,800℃时残炭率在30%左右。7种动力学分析方法显示聚合物的热分解活化能为92.95 k J/mol,指前因子lgA=4.71 s-1,n=2,分解符合二维扩散机理,对应的机理微分函数f(α)=(1-α)1/2[1-(1-α)1/2]-1积分函数g(α)=[1-(1-α)1/2]2聚合物的热分解反应方程为dα/dT=(5.14×104/β)exp(-92.95×103/RT)×(1-α)1/2×[1-(1-α)展开更多
Based on viscoelastic theory, two new computational methods of solving linear equations and minimum value of the l-norm were put forward for transforming Kohlransch-William-Watts （KWW） function of viscoelastic mater...Based on viscoelastic theory, two new computational methods of solving linear equations and minimum value of the l-norm were put forward for transforming Kohlransch-William-Watts （KWW） function of viscoelastic materials to the generalized Maxwell model. The computational methods for the Maxwell model fitting were achieved in MATLAB software. It is found that fitting precision of the two methods is very high. The method of solving linear equations needs more fitting points and more numbers of Maxwell units. It makes the program of finite element analysis complex. While the method of solving minimum value of 1-norm can obtain very high precision only using less fitting points. These methods can fit not only experimental curve of KWW function, but also the experimental data directly.展开更多
Since there is lack of methodology to assess the performance of defogging algorithm and the existing assessment methods have some limitations,three new methods for assessing the defogging algorithm were proposed.One w...Since there is lack of methodology to assess the performance of defogging algorithm and the existing assessment methods have some limitations,three new methods for assessing the defogging algorithm were proposed.One was using synthetic foggy image simulated by image degradation model to assess the defogging algorithm in full-reference way.In this method,the absolute difference was computed between the synthetic image with and without fog.The other two were computing the fog density of gray level image or constructing assessment system of color image from human visual perception to assess the defogging algorithm in no-reference way.For these methods,an assessment function was defined to evaluate algorithm performance from the function value.Using the defogging algorithm comparison,the experimental results demonstrate the effectiveness and reliability of the proposed methods.展开更多
文摘为研究聚乙烯基三苯乙炔基硅烷树脂的热分解机理,利用TG-DTG技术探讨了聚乙烯基三苯乙炔基硅烷树脂的非等温热分解过程.借助非模型拟合法和模型拟合法分析了聚乙烯基三苯乙炔基硅烷树脂(PVTPES)的热分解行为,建立了动力学函数,得到了聚乙烯基三苯乙炔基硅烷树脂的热分解反应机理.结果表明,6种热分析方法计算得到PVTPES的热分解活化能(E)在240 k J/mol左右,指前因子lg A=15.51,机理符合三维(3D)扩散控制机理.聚合物PVTPES的热分解过程分析进一步证实芳炔单体的热聚合为环三聚反应.
文摘运用TG-DTG技术研究了炔丙基改性酚醛树脂聚合物的非等温热分解过程,通过Kissinger法和FWO法获得聚合物分解的动力学参数,利用模型拟合法推测该聚合物的热分解机理,并用非模型拟合法对机理进行了验证。实验结果表明,该聚合物的Td5分解温度在390℃左右,800℃时残炭率在30%左右。7种动力学分析方法显示聚合物的热分解活化能为92.95 k J/mol,指前因子lgA=4.71 s-1,n=2,分解符合二维扩散机理,对应的机理微分函数f(α)=(1-α)1/2[1-(1-α)1/2]-1积分函数g(α)=[1-(1-α)1/2]2聚合物的热分解反应方程为dα/dT=(5.14×104/β)exp(-92.95×103/RT)×(1-α)1/2×[1-(1-α)
基金Project (50605063) supported by the National Natural Science Foundation of ChinaProject(NCET-040753) supported by New Century Excellent Talents in University, ChinaProject (20050533037) supported by the Doctoral Program of Higher Education, China
文摘Based on viscoelastic theory, two new computational methods of solving linear equations and minimum value of the l-norm were put forward for transforming Kohlransch-William-Watts （KWW） function of viscoelastic materials to the generalized Maxwell model. The computational methods for the Maxwell model fitting were achieved in MATLAB software. It is found that fitting precision of the two methods is very high. The method of solving linear equations needs more fitting points and more numbers of Maxwell units. It makes the program of finite element analysis complex. While the method of solving minimum value of 1-norm can obtain very high precision only using less fitting points. These methods can fit not only experimental curve of KWW function, but also the experimental data directly.
基金Projects(91220301,61175064,61273314)supported by the National Natural Science Foundation of ChinaProject(126648)supported by the Postdoctoral Science Foundation of Central South University,ChinaProject(2012170301)supported by the New Teacher Fund for School of Information Science and Engineering,Central South University,China
文摘Since there is lack of methodology to assess the performance of defogging algorithm and the existing assessment methods have some limitations,three new methods for assessing the defogging algorithm were proposed.One was using synthetic foggy image simulated by image degradation model to assess the defogging algorithm in full-reference way.In this method,the absolute difference was computed between the synthetic image with and without fog.The other two were computing the fog density of gray level image or constructing assessment system of color image from human visual perception to assess the defogging algorithm in no-reference way.For these methods,an assessment function was defined to evaluate algorithm performance from the function value.Using the defogging algorithm comparison,the experimental results demonstrate the effectiveness and reliability of the proposed methods.
