Tailings impoundments can potentially collapse due to damage caused by earthquakes,which has frequently occurred around the world.This study takes the proposed valley type tailings impoundment in Yunnan as the researc...Tailings impoundments can potentially collapse due to damage caused by earthquakes,which has frequently occurred around the world.This study takes the proposed valley type tailings impoundment in Yunnan as the research object to analyze the dynamic response behavior under earthquake action with both numerical simulation and physical model test(1:300).The results of both tests show that the dynamic response of the valley type tailings impoundment is characterized by"medium stiffness effect",in other words,in a certain range,the"softer"the unsaturated tailings sand is,the more energy it can dissipate,which leads the decrease of the value of the acceleration amplification factor.In addition,the peak acceleration of the monitoring points increases with the vertical elevation,which indicates that the"elevation amplification effect"exists in the tailings impoundment dynamic response.The middle part of the outer side of the raised embankment reacts more sensitive than the crest,which is similar to the slope dynamic response.The starter dam reacts sensitively under the earthquake excitation,which should be given more attention during the seismic design.The dynamic response rules reflected by the numerical simulation are consistent with the results monitored on the physical model test,although there are some differences between their values.The dynamic response rules of the valley type tailings impoundment can provide basis for the design of the similar projects in this region.展开更多
将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析...将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析。Si 4+掺杂不仅可降低材料的锂镍混排程度,还能增强结构稳定性,且不会改变材料的形貌。以40 mA/g(0.2 C)的电流在2.5~4.5 V充放电,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)正极材料具有最好的电化学性能,不仅比容量(149.25 mAh/g)较未掺杂材料(125.44 mAh/g)提高20%,而且容量保持率在120次循环后也提高了7.7%。Si 4+掺杂能降低材料的锂镍混排程度,有利于Li+的迁移;能提高材料的结构稳定性,抑制电压的下降并减轻极化。展开更多
基金financially supported by project (Grant NO. U1502232, U1033601)-National Science Foundation of China-Yunnan Joint Fundproject (Grant NO. 20135314110005)-Research Fund for the Doctoral Program of Higher Education of China
文摘Tailings impoundments can potentially collapse due to damage caused by earthquakes,which has frequently occurred around the world.This study takes the proposed valley type tailings impoundment in Yunnan as the research object to analyze the dynamic response behavior under earthquake action with both numerical simulation and physical model test(1:300).The results of both tests show that the dynamic response of the valley type tailings impoundment is characterized by"medium stiffness effect",in other words,in a certain range,the"softer"the unsaturated tailings sand is,the more energy it can dissipate,which leads the decrease of the value of the acceleration amplification factor.In addition,the peak acceleration of the monitoring points increases with the vertical elevation,which indicates that the"elevation amplification effect"exists in the tailings impoundment dynamic response.The middle part of the outer side of the raised embankment reacts more sensitive than the crest,which is similar to the slope dynamic response.The starter dam reacts sensitively under the earthquake excitation,which should be given more attention during the seismic design.The dynamic response rules reflected by the numerical simulation are consistent with the results monitored on the physical model test,although there are some differences between their values.The dynamic response rules of the valley type tailings impoundment can provide basis for the design of the similar projects in this region.
文摘将共沉淀法和固相法相结合,将Si 4+掺杂到LiNi 0.5 Mn 0.5 O 2中,合成LiNi 0.5-x Si x Mn 0.5 O 2(0≤x≤0.08)正极材料。通过XRD及精修、等离子体发射光谱(ICP)、SEM和透射电子显微镜(TEM)等方法,对合成材料的结构、成分和形貌进行分析。Si 4+掺杂不仅可降低材料的锂镍混排程度,还能增强结构稳定性,且不会改变材料的形貌。以40 mA/g(0.2 C)的电流在2.5~4.5 V充放电,LiNi 0.47 Si 0.03 Mn 0.5 O 2(x=0.03)正极材料具有最好的电化学性能,不仅比容量(149.25 mAh/g)较未掺杂材料(125.44 mAh/g)提高20%,而且容量保持率在120次循环后也提高了7.7%。Si 4+掺杂能降低材料的锂镍混排程度,有利于Li+的迁移;能提高材料的结构稳定性,抑制电压的下降并减轻极化。
