硫源和六元瓜环对硫化镉性质的影响

以硫代硫酸钠和硫脲为硫源,氯化镉为镉源,六元瓜环(Q[6])为修饰剂,采用水热法制备Q[6]/CdS复合光催化剂.利用傅里叶变换红外光谱、X射线粉末衍射和扫描电子显微镜对产物进行结构和形貌表征,考察Q[6]和硫源对产物结构和性能的影响.结果表明,硫源对产物形貌和结构都有影响,Q[6]对硫化镉光催化性能有增强作用,15 mg Q[6]/CdS能使50 mL,6 mg/L的次甲基蓝溶液反应200 min时的降解率达到93.0;以上.     

瓜环和金属改性的硫化镉光催化性质

以硫代乙酰胺为硫源,氯化镉为镉源,超声法制备银、钴离子掺杂的六元瓜环-硫化镉复合物。采用X射线粉末衍射、傅里叶变换红外光谱和扫描电子显微镜对催化剂结构和形貌进行表征,并进行催化降解染料的测试,考察Q[6]和金属离子对催化剂催化性能的影响。结果表明:采用瓜环复合和适量金属掺杂能使硫化镉可见光催化降解亚甲基蓝的性能显著提高约20%,且以瓜环对硫化镉协同增效作用为主。     

Stochastic Gradient Descent and Anomaly of Variance-Flatness Relation in Artificial Neural Networks

Stochastic gradient descent(SGD), a widely used algorithm in deep-learning neural networks, has attracted continuing research interests for the theoretical principles behind its success. A recent work reported an anomaly(inverse) relation between the variance of neural weights and the landscape flatness of the loss function driven under SGD [Feng Y and Tu Y Proc. Natl. Acad. Sci. USA 118 e2015617118(2021)]. To investigate this seeming violation of statistical physics principle, the properties of...