To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content ...To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.展开更多
单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,...单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。展开更多
在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order general...在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order generalized integral,SOGI)的可变增益母线电压纹波前馈控制方法。采用SOGI提取母线电压纹波信息,基于品质因数Q与电压增益的关系和母线电压纹波对归一化频率的影响,解析了母线电压纹波对CLLLC谐振变换器输出电压的影响机理,得到Q值与前馈增益系数Ka的关系,采用仿真寻优加数据拟合的方法得到前馈可变增益系数曲线。仿真和实验结果表明,相比于无前馈控制,所提控制方法对CLLLC谐振变换器的输出电压纹波具有较好的抑制效果,输出电压纹波降低了72%,验证了所提算法的有效性。展开更多
基金Supported by the Science and Technology Cooperation and Exchange special project of Cooperation of Shanxi Province(202404041101014)the Fundamental Research Program of Shanxi Province(202403021212333)+3 种基金the Joint Funds of the National Natural Science Foundation of China(U24A20555)the Lvliang Key R&D of University-Local Cooperation(2023XDHZ10)the Initiation Fund for Doctoral Research of Taiyuan University of Science and Technology(20242026)the Outstanding Doctor Funding Award of Shanxi Province(20242080).
文摘To elucidate the effect of calcite-regulated activated carbon(AC)structure on low-temperature denitrification performance of SCR catalysts,this work prepared a series of Mn-Ce/De-AC-xCaCO_(3)(x is the calcite content in coal)catalysts were prepared by the incipient wetness impregnation method,followed by acid washing to remove calcium-containing minerals.Comprehensive characterization and low-temperature denitrification tests revealed that calcite-induced structural modulation of coal-derived AC significantly enhances catalytic activity.Specifically,NO conversion increased from 88.3%of Mn-Ce/De-AC to 91.7%of Mn-Ce/De-AC-1CaCO_(3)(210℃).The improved SCR denitrification activity results from the enhancement of physicochemical properties including higher Mn^(4+)content and Ce^(4+)/Ce^(3+)ratio,an abundance of chemisorbed oxygen and acidic sites,which could strengthen the SCR reaction pathways(richer NH_(3)activated species and bidentate nitrate active species).Therefore,NO removal is enhanced.
文摘单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。
