针对一类具有未知函数控制增益的多输入多输出(M IM O)非线性系统,基于后推设计方法和动态面控制技术,提出一种间接自适应神经网络控制方案.该方案通过引入1阶滤波器,消除了后推设计中由于反复对虚拟控制的求导而导致的复杂性问题,并避...针对一类具有未知函数控制增益的多输入多输出(M IM O)非线性系统,基于后推设计方法和动态面控制技术,提出一种间接自适应神经网络控制方案.该方案通过引入1阶滤波器,消除了后推设计中由于反复对虚拟控制的求导而导致的复杂性问题,并避免了反馈线性化方法可能出现的控制器奇异性问题,参数估计无需使用投影算法.利用李亚普诺夫方法,证明了闭环系统半全局一致终结有界,通过适当选取设计常数,跟踪误差可收敛到原点的一个小邻域内.仿真结果表明了该方法的有效性.展开更多
Platinum is a cornerstone catalyst for various chemical and electrochemical transformations.Atomically precise platinum nanoclusters,located at the transition stage between smaller platinum-ligandcoordinationmolecules...Platinum is a cornerstone catalyst for various chemical and electrochemical transformations.Atomically precise platinum nanoclusters,located at the transition stage between smaller platinum-ligandcoordinationmolecules(<~1 nm)and larger platinumcolloidalnanoparticles(>∼3 nm),cancombine the advantages of both homogeneous and heterogeneous catalysts,serving as model systems for understanding catalytic processes.However,compared to significant advances in coinage metal nanoclusters,atomically precise platinum nanoclusters remain largely unexplored.Here,we introduce the rich history and highlight the recent renaissance of atomically precise Pt clusters,focusing on their synthesis,structures,and properties.We discuss(i)how the sizes can be precisely controlled through the redox chemistry of one-dimensional platinum carbonyl clusters,(ii)how the core structures can be diversified in three-dimensional Ptn(CO)m clusters,(iii)how the surface properties can be tailored by using various types of ligands,and(iv)recent progress in evaluating these clusters in electrochemical and thermal catalytic reactions.By bridging the gaps among conventional coordination,cluster,colloidal,and catalytic chemistry,we expect to provide some fundamental insights that are crucial for designing more efficient platinum cluster catalysts with atomic precision.展开更多
文摘针对一类具有未知函数控制增益的多输入多输出(M IM O)非线性系统,基于后推设计方法和动态面控制技术,提出一种间接自适应神经网络控制方案.该方案通过引入1阶滤波器,消除了后推设计中由于反复对虚拟控制的求导而导致的复杂性问题,并避免了反馈线性化方法可能出现的控制器奇异性问题,参数估计无需使用投影算法.利用李亚普诺夫方法,证明了闭环系统半全局一致终结有界,通过适当选取设计常数,跟踪误差可收敛到原点的一个小邻域内.仿真结果表明了该方法的有效性.
基金the ACS Petroleum Research Fund 67111-ND3the University of Florida start-up research fund。
文摘Platinum is a cornerstone catalyst for various chemical and electrochemical transformations.Atomically precise platinum nanoclusters,located at the transition stage between smaller platinum-ligandcoordinationmolecules(<~1 nm)and larger platinumcolloidalnanoparticles(>∼3 nm),cancombine the advantages of both homogeneous and heterogeneous catalysts,serving as model systems for understanding catalytic processes.However,compared to significant advances in coinage metal nanoclusters,atomically precise platinum nanoclusters remain largely unexplored.Here,we introduce the rich history and highlight the recent renaissance of atomically precise Pt clusters,focusing on their synthesis,structures,and properties.We discuss(i)how the sizes can be precisely controlled through the redox chemistry of one-dimensional platinum carbonyl clusters,(ii)how the core structures can be diversified in three-dimensional Ptn(CO)m clusters,(iii)how the surface properties can be tailored by using various types of ligands,and(iv)recent progress in evaluating these clusters in electrochemical and thermal catalytic reactions.By bridging the gaps among conventional coordination,cluster,colloidal,and catalytic chemistry,we expect to provide some fundamental insights that are crucial for designing more efficient platinum cluster catalysts with atomic precision.
