Thermal Conductivity Anomalies Related to the Double-Bump of Resistivity in Nd0.7Sr0.3Mn1-xCrxO3

The temperature dependence of the thermal conductivity κ(T) and electrical resistivity ρ(T) has been measured for perovskite Nd0.7Sr0.3Mn1-xCrxO3 (0.01≤x≤0.15) in the temperature range of 10-300 K. The double-bump feature in p(T) is observed for x = 0.08 and 0.10 samples. Below the insulating-metallic transition temperature TIM, κ(T) shows a sharp increase and such an increase is depressed gradually by the increasing Cr content.While κ(T) displays an anomalous decrease around the temperature where the second bump of ρ(T) emerges.We suggest that the enhancement of κ(T) below TIM is related to both phonons and magnons, the ferromagnetic interaction of Mn^3 -O-Cr^3 should be super-exchange interaction rather than double-exchange interaction, and the Cr doping just weakens the DE interaction in this system.     

进料有机负荷及回流比对餐厨垃圾协同水葫芦发酵产氢的影响研究

有机固体废物进行多组分协同厌氧发酵可以产生清洁能源气体,从而达到资源化处理的目的.本文通过设置不同进料有机负荷及回流比,分析餐厨垃圾协同水葫芦厌氧产氢过程中产气量、氢气含量、SCOD、挥发性脂肪酸(VFAs)、pH及氨氮(NH⁺-N)各参数的变化.结果显示,高有机负荷和高回流比会导致系统的VFAs累积,使系统pH值降到5.0以下;进料有机负荷对于餐厨垃圾协同水葫芦厌氧产氢的影响更大,系统内的氨氮浓度及SCOD浓度均与进料有机负荷呈正相关;当进料有机负荷为10 kg·m^-3·d^-1、回流比为30%时,系统产氢效果最好,累计产气量为80 946 m L,氢气含量为35.83%.本研究结果可为有机固体废物资源化处理提供参考.