固相(微)萃取-室温磷光联用技术及其应用

综述了固相(微)萃取-室温磷光技术的主要方法以及在环境分析中的应用。主要从固相萃取的基本原理、装置、操作步骤、分离模式及填料等方面评述了固相(微)萃取技术的特点和应用,评述了室温磷光技术的优点和经典室温磷光技术在操作方法和定量分析方面存在的不足,提出了固相(微)萃取和室温磷光联用技术的必然性及其优点,并对该方法的关键技术和存在的难题进行了分析。该技术结合了富集技术与高选择性的磷光分析方法,使得分析的灵敏度进一步提高,选择性也得到了较大的改进。目前常用的固相萃取填料主要有Whatman 1PS滤纸和填充有C₁₈或C₈盘或(膜),目标分析物主要集中在多环芳烃、多氯联苯和多氯联苯呋喃等物质的分析,应用前景十分广泛。     

Thermoelectric properties of Li-doped Sr_(0.7)Ba_(0.3)Nb_2O_(6-δ) ceramics

Thermoelectric properties of Li-dopedSr_(0.7)Ba_(0.3)Nb_2O_(6-δ)ceramics were investigated in the temperature range from 323 K to 1073 K. The electrical conductivity increases significantly after lithium interstitial doping. However, both of the magnitudes of Seebeck coefficient and electrical conductivity vary non-monotonically but synchronously with the doping contents, indicating that doped lithium ions may not be fully ionized and oxygen vacancy may also contribute to carriers. The lattice thermal conductivity increases firstly and then decreases as the doping content increases, which is affected by competing factors.Thermoelectric performance is enhanced by lithium interstitial doping due to the increase of the power factor and the thermoelectric figure of merit reaches maximum value(0.21 at 1073 K) in the sample Sr_(0.70)Ba_(0.30)Li_(0.10)Nb_2O_6.