A high-pressure quartz crystal microbalance(QCM)apparatus was developed to investigate the absorption of carbon dioxide in two glassy polymer films—polystyrene(PS)and polyvinylpyrrolidone(PVP)at 40℃ and pressure up ...A high-pressure quartz crystal microbalance(QCM)apparatus was developed to investigate the absorption of carbon dioxide in two glassy polymer films—polystyrene(PS)and polyvinylpyrrolidone(PVP)at 40℃ and pressure up to 9.0 MPa.PVP was shown to have better CO2 absorption and chosen as the representative for supercritical impregnation of two model drugs—o-aminobenzoic acid and ibuprofen at 40℃ and pressure up to 8.0 MPa.It was found that the two impregnants were embedded into the polymer with a partition coefficient as high as 104 order of magnitude.Since the sub-microweighing technique established and utilized in this study was simple,convenient and accurate,it was believed that the technique could have wide and effective applications in supercritical impregnation processes.展开更多
The feasibility of a piezoelectric quartz trichlorfon sensor based on the Molecularly Imprinting Technology was described,and the trichlorfon sensor was devised by depositing the poly o-phenylenediamine onto one side ...The feasibility of a piezoelectric quartz trichlorfon sensor based on the Molecularly Imprinting Technology was described,and the trichlorfon sensor was devised by depositing the poly o-phenylenediamine onto one side of an Pt-cut quartz crystal through electrochemical polymerization process(Cyclic voltam-metry).The sensor showed high selectivity and sensitivity in aqueous system.A linear relationship between the frequency shift and the concentration of trichlorfon in the range of 5×10-9mol/L～1.0×10-7 mol/L was obtained,and the detection limit was 1.0×10-9mol/L.展开更多
文摘以碳酸锰(Mn CO_3)为前体,空气氛围下采用不同温度(300℃、350℃、400℃)煅烧,制备了3种介孔二氧化锰(Mn O_2)材料,分别与粘结剂混合喷涂至石英晶片作为电极,利用石英晶体微天平(QCM)监测了3种材料在0.1 mol/L Na_2SO_4溶液中随循环伏安过程的电化学性能变化。分析结果表明,3种材料在首圈循环中都呈现出显著的质量增加,发生了不可逆反应过程;300℃煅烧制备的Mn O_2材料具备更好的电化学稳定性和容量保持能力。将300℃,350℃和400℃煅烧的Mn O_2各自作为正极与活性炭负极组成超级电容器,进行充放电测试,首圈均有35%~40%的容量损失;三者稳定循环时放电容量分别为15.9,12.9和11.7 m A h/g。QCM的分析与充放电测试结果相一致,表明QCM可用于比较不同介孔二氧化锰材料的电化学性能。
文摘A high-pressure quartz crystal microbalance(QCM)apparatus was developed to investigate the absorption of carbon dioxide in two glassy polymer films—polystyrene(PS)and polyvinylpyrrolidone(PVP)at 40℃ and pressure up to 9.0 MPa.PVP was shown to have better CO2 absorption and chosen as the representative for supercritical impregnation of two model drugs—o-aminobenzoic acid and ibuprofen at 40℃ and pressure up to 8.0 MPa.It was found that the two impregnants were embedded into the polymer with a partition coefficient as high as 104 order of magnitude.Since the sub-microweighing technique established and utilized in this study was simple,convenient and accurate,it was believed that the technique could have wide and effective applications in supercritical impregnation processes.
文摘The feasibility of a piezoelectric quartz trichlorfon sensor based on the Molecularly Imprinting Technology was described,and the trichlorfon sensor was devised by depositing the poly o-phenylenediamine onto one side of an Pt-cut quartz crystal through electrochemical polymerization process(Cyclic voltam-metry).The sensor showed high selectivity and sensitivity in aqueous system.A linear relationship between the frequency shift and the concentration of trichlorfon in the range of 5×10-9mol/L～1.0×10-7 mol/L was obtained,and the detection limit was 1.0×10-9mol/L.
