以煤加工副产物煤焦油中蒽油馏分为碳源、多巴胺为氮源,基于纳米碳酸钙球模板在碳化过程中发生的诱导自活化作用,一步共碳化制得氮掺杂多孔碳(NPCs)材料。通过元素分析、低温氮气吸附-脱附测试、扫描及透射电镜表征,结果表明,NPCs材料...以煤加工副产物煤焦油中蒽油馏分为碳源、多巴胺为氮源,基于纳米碳酸钙球模板在碳化过程中发生的诱导自活化作用,一步共碳化制得氮掺杂多孔碳(NPCs)材料。通过元素分析、低温氮气吸附-脱附测试、扫描及透射电镜表征,结果表明,NPCs材料的氮元素掺杂量高,且具有发达的微孔-介孔梯级孔道结构。结合室温下催化硫化氢选择性氧化为单质硫的反应性能评价,发现改变模板剂用量、碳/氮源投料比和碳化温度,可调控NPCs材料的氮掺杂量(质量分数6.4%~21.3%)、比表面积、孔道结构发达程度及相应的定向转化硫容,最佳工艺条件下合成样品的饱和硫容高达5.8 g H2S/(g催化剂)。展开更多
In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. ...In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. In order to acquire the imperfect channel state information at transmitter (CSIT), a dynamic CSIT model is introduced where the channel temporal and spatial correlations are considered. By utilizing the unchanged channel statistics and accurate outdated feedback channel information jointly, the imperfect CSIT is obtained as the channel estimate and error covariance. Based on the obtained imperfect CSIT, a Minimum Mean-Square Error (MMSE) Tomlinsion-Harashima precoding (THP) is designed and the closed-form solution is derived by the Lagrangian multiplier approach under total power constraint. Simulation results are provided to indicate the preferable performances of the robust THP. Performance analysis with respect to feedback delay and mobile speed is also given.展开更多
文摘以煤加工副产物煤焦油中蒽油馏分为碳源、多巴胺为氮源,基于纳米碳酸钙球模板在碳化过程中发生的诱导自活化作用,一步共碳化制得氮掺杂多孔碳(NPCs)材料。通过元素分析、低温氮气吸附-脱附测试、扫描及透射电镜表征,结果表明,NPCs材料的氮元素掺杂量高,且具有发达的微孔-介孔梯级孔道结构。结合室温下催化硫化氢选择性氧化为单质硫的反应性能评价,发现改变模板剂用量、碳/氮源投料比和碳化温度,可调控NPCs材料的氮掺杂量(质量分数6.4%~21.3%)、比表面积、孔道结构发达程度及相应的定向转化硫容,最佳工艺条件下合成样品的饱和硫容高达5.8 g H2S/(g催化剂)。
基金supported by National Basic Research Program of China (973 Program) (Grant No. 2007CB310604, 2009CB320401)National Natural Science Foundation of China (Grant No. 60772108, 60702048)
文摘In this paper, a robust THP is proposed for broadcast channel in multi-user multi-input multi-output (MU-MIMO) system, in which the channel uncertainty caused by feedback delay and mobile speed is taken into account. In order to acquire the imperfect channel state information at transmitter (CSIT), a dynamic CSIT model is introduced where the channel temporal and spatial correlations are considered. By utilizing the unchanged channel statistics and accurate outdated feedback channel information jointly, the imperfect CSIT is obtained as the channel estimate and error covariance. Based on the obtained imperfect CSIT, a Minimum Mean-Square Error (MMSE) Tomlinsion-Harashima precoding (THP) is designed and the closed-form solution is derived by the Lagrangian multiplier approach under total power constraint. Simulation results are provided to indicate the preferable performances of the robust THP. Performance analysis with respect to feedback delay and mobile speed is also given.
