Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underly...Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underlying autocorrelation functions through molecular dynamics simulations(MD-ACF).The energy landscapes are represented by a machine-learned potential that describes both the ground and excited state landscapes through a single model,guaranteeing size-consistent predictions.We apply this methodology to the(V_(Si)V_(C))_(kk)^(0)divacancy defect in 4H-SiC and demonstrate that at low temperatures,the present MD-ACF approach reproduces results from the traditional generating function approach.Unlike the latter,it is,however,also applicable at high temperatures as it avoids harmonic and parallel-mode approximations and can be applied to study non-crystalline materials.The MD-ACF methodology thus promises to substantially widen the range of computational predictions of the optical properties of color centers and related defects.展开更多
为了研究室外视距(line of sight,Lo S)和非视距(non-Lo S,NLo S)传输场景中车辆与车辆(vehicle-to-vehicle,V2V)之间的无线通信系统,提出一种基于几何街道散射场景的统计信道模型,其发射端和接收端都处于移动状态。先假设有无穷多的散...为了研究室外视距(line of sight,Lo S)和非视距(non-Lo S,NLo S)传输场景中车辆与车辆(vehicle-to-vehicle,V2V)之间的无线通信系统,提出一种基于几何街道散射场景的统计信道模型,其发射端和接收端都处于移动状态。先假设有无穷多的散射体随机分布在街道两侧;并且在发射端和接收端都采用多天线技术,然后模型定量给出了几何街道散射场景下到发射角(angle of arrival,AOD)和到达角(angle of arrival,AOA)之间的几何关系。同时研究了信号在几何散射信道模型中的空间互相关函数、时间自相关函数(autocorrelation function,ACF)、频率互相关函数以及多普勒功率谱密度(power spectral density,PSD)的影响。理论分析和仿真结果表明提出的V2V通信系统的无线信道的统计特性符合理论和经验,拓展了多输入多输出宽带V2V通信系统的研究。展开更多
文摘集中供热系统实际调控方式受环境因素等影响,常偏离预定调控方案,核实集中供热系统实际调控方式是实现系统节能优化的前提。本文综合采用ACF(Autocorrelation Function)自相关函数、相关性分析和STL(Seasonal-Trend Decomposition Using LOESS)时间序列分解等数据挖掘技术有效结合,提出了一套通过运行数据识别系统实际调控方式的方法。将提出的方法应用于实际案例的换热站中,结果表明可以识别出该换热站实际调控方式,验证了所提方法的可行性。最终确定该换热站实际调控方式与预定方案之间存在差异,并总结导致实际调控方式产生差异的原因。
基金funding from the Swedish Research Council(Nos.2020-04935 and 2021-05072)as well as computational resources provided by the National Academic Infrastructure for Supercomputing in Sweden at NSC,PDCC3SE partially funded by the Swedish Research Council through grant agreement No.2022-06725+1 种基金as well as the Berzelius resource provided by the Knut and Alice Wallenberg Foundation at NSC.Parts of the computations were performed on resources provided by UNINETT Sigma2-the National Infrastructure for High-Performance Computing and Data Storage in Norway.C.L.acknowledges the support provided by the Research Council of Norway and the University of Oslo through the research project QuTe(no.325573,FriPro ToppForsk-program)funding from the Swedish Strategic Research Foundation through a Future Research Leader program(FFL21-0129).
文摘Color centers play key roles in,e.g.,solid state lighting and quantum information technology.Here,we describe an approach for predicting the optical line shapes of such emitters based on direct sampling of the underlying autocorrelation functions through molecular dynamics simulations(MD-ACF).The energy landscapes are represented by a machine-learned potential that describes both the ground and excited state landscapes through a single model,guaranteeing size-consistent predictions.We apply this methodology to the(V_(Si)V_(C))_(kk)^(0)divacancy defect in 4H-SiC and demonstrate that at low temperatures,the present MD-ACF approach reproduces results from the traditional generating function approach.Unlike the latter,it is,however,also applicable at high temperatures as it avoids harmonic and parallel-mode approximations and can be applied to study non-crystalline materials.The MD-ACF methodology thus promises to substantially widen the range of computational predictions of the optical properties of color centers and related defects.
文摘为了研究室外视距(line of sight,Lo S)和非视距(non-Lo S,NLo S)传输场景中车辆与车辆(vehicle-to-vehicle,V2V)之间的无线通信系统,提出一种基于几何街道散射场景的统计信道模型,其发射端和接收端都处于移动状态。先假设有无穷多的散射体随机分布在街道两侧;并且在发射端和接收端都采用多天线技术,然后模型定量给出了几何街道散射场景下到发射角(angle of arrival,AOD)和到达角(angle of arrival,AOA)之间的几何关系。同时研究了信号在几何散射信道模型中的空间互相关函数、时间自相关函数(autocorrelation function,ACF)、频率互相关函数以及多普勒功率谱密度(power spectral density,PSD)的影响。理论分析和仿真结果表明提出的V2V通信系统的无线信道的统计特性符合理论和经验,拓展了多输入多输出宽带V2V通信系统的研究。
