以多氯联苯分子的范德华体积、偶极矩、平均分子极化率和分子椭圆度等分子结构信息为基础,通过线性多元回归建立了它们与正辛醇—空气分配系数K OA的定量结构—性质关系(QSPRs),预测了一些多氯联苯的K OA。同时研究了分子结构数据对K O...以多氯联苯分子的范德华体积、偶极矩、平均分子极化率和分子椭圆度等分子结构信息为基础,通过线性多元回归建立了它们与正辛醇—空气分配系数K OA的定量结构—性质关系(QSPRs),预测了一些多氯联苯的K OA。同时研究了分子结构数据对K OA的影响,结果表明对K OA影响最大的是范德华体积和平均分子极化率。苯环上氯原子数越多,对-log K OA的影响越大,非邻位氯取代的多氯联苯分子的-log K OA较大,其次是单邻位取代的多氯联苯分子的-log K OA,双邻位取代的多氯联苯分子的-log K OA较小。展开更多
The non-linear relations exist between the temperature,pressure,and concentration with the flux and retention coefficient of Agaricus Blazei Murill polysaccharide solution during ultrafiltration(UF) separation.The mod...The non-linear relations exist between the temperature,pressure,and concentration with the flux and retention coefficient of Agaricus Blazei Murill polysaccharide solution during ultrafiltration(UF) separation.The models of UF were built by back-propagation algorithm based on Neural Network Toolbox(NNT)of MATLAB.The parameters of model were discussed,such as the number of hidden layer node,learning method and learning rate.The results show that the network system was 3×13×1,and there is a good agreement between experimental data and modeled data with prediction precision 1.67% and 3.75%.展开更多
Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties...Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties were systematically characterized by TEM, granularity distribution, TG-DTA, XRD and gas sensitivity measurements. The particle size is about 10 nm and size distribution is very narrow. The sensitivity of the sensing element to CO, H2, C2H4, C6H6 and the effects of calcination temperature on the sensitivity and conductance of gases were examined. The combination of excellent thermal stability and tunable gas sensing properties through careful control of the preparation and judicious selection of material compositions gives rise to novel nanocomposites, which is attractive for the sensitive and selective detection of reducing gases and some hydrocarbon gases.展开更多
文摘以多氯联苯分子的范德华体积、偶极矩、平均分子极化率和分子椭圆度等分子结构信息为基础,通过线性多元回归建立了它们与正辛醇—空气分配系数K OA的定量结构—性质关系(QSPRs),预测了一些多氯联苯的K OA。同时研究了分子结构数据对K OA的影响,结果表明对K OA影响最大的是范德华体积和平均分子极化率。苯环上氯原子数越多,对-log K OA的影响越大,非邻位氯取代的多氯联苯分子的-log K OA较大,其次是单邻位取代的多氯联苯分子的-log K OA,双邻位取代的多氯联苯分子的-log K OA较小。
文摘The non-linear relations exist between the temperature,pressure,and concentration with the flux and retention coefficient of Agaricus Blazei Murill polysaccharide solution during ultrafiltration(UF) separation.The models of UF were built by back-propagation algorithm based on Neural Network Toolbox(NNT)of MATLAB.The parameters of model were discussed,such as the number of hidden layer node,learning method and learning rate.The results show that the network system was 3×13×1,and there is a good agreement between experimental data and modeled data with prediction precision 1.67% and 3.75%.
基金Supported by the National Natural Science Foundation of China (No. 20377004) and Beijing Natural Science Foundation (No. 2032014, No. 8032007).
文摘Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties were systematically characterized by TEM, granularity distribution, TG-DTA, XRD and gas sensitivity measurements. The particle size is about 10 nm and size distribution is very narrow. The sensitivity of the sensing element to CO, H2, C2H4, C6H6 and the effects of calcination temperature on the sensitivity and conductance of gases were examined. The combination of excellent thermal stability and tunable gas sensing properties through careful control of the preparation and judicious selection of material compositions gives rise to novel nanocomposites, which is attractive for the sensitive and selective detection of reducing gases and some hydrocarbon gases.
