Based on J/ψ events collected with the BESIII detector,with corresponding Monte Carlo samples,the tracking efficiency and its systematic uncertainty are studied using a control sample of J/ψ→pp^-π＋π^-.Validation...Based on J/ψ events collected with the BESIII detector,with corresponding Monte Carlo samples,the tracking efficiency and its systematic uncertainty are studied using a control sample of J/ψ→pp^-π＋π^-.Validation methods and different factors influencing the tracking efficiency are presented in detail.The tracking efficiency and its systematic uncertainty for protons and pions with the transverse momentum and polar angle dependence are also discussed.展开更多
In this paper, a Hybrid MPPT algorithm is proposed to improve the efficiency of photovoltaic (PV) systems under partial shading conditions. Partial shading occurs due to clouds, trees, dirt and dust in ...In this paper, a Hybrid MPPT algorithm is proposed to improve the efficiency of photovoltaic (PV) systems under partial shading conditions. Partial shading occurs due to clouds, trees, dirt and dust in PV systems. In partial shading, multiple peaks arise in the PV characteristic curve. The Maximum power point tracking (MPPT) algorithm adjusts the duty cycle of the switch in DC-DC converter for regulating the input voltage at the Maximum power point (MPP) and to provide impedance matching i.e. input resistance of converter equal to equivalent solar resistance of PV system at MPP for the maximum power transfer. The Cuk converters have low switching losses and the highest efficiency. Therefore Cuk converter is chosen as power conditioning circuit to trackmaximum power using Hybrid MPPT technique. The influence of algorithm parameters on system behaviour is investigated and the various advantages and drawbacks of the technique are identified for different weather conditions. Practical results obtained using Solartech SPMO85P PV modules connected to a RL load through Hybrid MPPT controller validates the simulated results.展开更多
Background The multilayer drift chamber(MDC)is one of the key detectors at the BESIII,which is mainly responsible for the precise measurement of charged particles.High reconstruction efficiency of charged particles wi...Background The multilayer drift chamber(MDC)is one of the key detectors at the BESIII,which is mainly responsible for the precise measurement of charged particles.High reconstruction efficiency of charged particles with a wide range of momentums is a basic requirement for the MDC reconstruction software.Purpose The purpose is to improve the tracking efficiency at the low transverse momentum region.Methods The Hough transform is a mathematical method that can map hits in a detector to parameter space to find tracks globally.In this paper,we have used it as the basis for developing a new tracking algorithm to find tracks in MDC.In addition,the drift distances of hits are considered when implementing Hough transform.Results This tracking algorithm is implemented in the BESIII offline software system,and its performance is checked using both Monte Carlo and data.The results show that this tracking method improves reconstruction efficiency at the low transverse momentum region.Conclusions The tracking algorithm based on Hough transform is proved to be beneficial for the MDC low transverse momentum tracking,and has been used in BESIII offline data reconstruction .展开更多
We present a study for matching charged tracks reconstructed from the ALICE tracking detectors with the clusters measured in the photon spectrometer. Matching efficiency and contaminations due to wrong matches have be...We present a study for matching charged tracks reconstructed from the ALICE tracking detectors with the clusters measured in the photon spectrometer. Matching efficiency and contaminations due to wrong matches have been deduced for charged pions and muons. For electrons, the effect of the material in front of PHOS is discussed.展开更多
基金Supported by Joint Funds of National Natural Science Foundation of China(U1232201)National Natural Science Foundation of China(11275210,11205182,11205184)National Key Basic Research Program of China(2015CB856700)
文摘Based on J/ψ events collected with the BESIII detector,with corresponding Monte Carlo samples,the tracking efficiency and its systematic uncertainty are studied using a control sample of J/ψ→pp^-π＋π^-.Validation methods and different factors influencing the tracking efficiency are presented in detail.The tracking efficiency and its systematic uncertainty for protons and pions with the transverse momentum and polar angle dependence are also discussed.
文摘In this paper, a Hybrid MPPT algorithm is proposed to improve the efficiency of photovoltaic (PV) systems under partial shading conditions. Partial shading occurs due to clouds, trees, dirt and dust in PV systems. In partial shading, multiple peaks arise in the PV characteristic curve. The Maximum power point tracking (MPPT) algorithm adjusts the duty cycle of the switch in DC-DC converter for regulating the input voltage at the Maximum power point (MPP) and to provide impedance matching i.e. input resistance of converter equal to equivalent solar resistance of PV system at MPP for the maximum power transfer. The Cuk converters have low switching losses and the highest efficiency. Therefore Cuk converter is chosen as power conditioning circuit to trackmaximum power using Hybrid MPPT technique. The influence of algorithm parameters on system behaviour is investigated and the various advantages and drawbacks of the technique are identified for different weather conditions. Practical results obtained using Solartech SPMO85P PV modules connected to a RL load through Hybrid MPPT controller validates the simulated results.
基金Funding was provided by National Key Basic Research Program of China under Contract No.2015CB856706National Natural Science Foundation of China(NSFC)under Contracts Nos.11475208,11775245,11335009,U1632106,11575222Chinese Academy of Sciences(CAS)President’s International Fellowship Initiative under Contract No.2018PM0004.
文摘Background The multilayer drift chamber(MDC)is one of the key detectors at the BESIII,which is mainly responsible for the precise measurement of charged particles.High reconstruction efficiency of charged particles with a wide range of momentums is a basic requirement for the MDC reconstruction software.Purpose The purpose is to improve the tracking efficiency at the low transverse momentum region.Methods The Hough transform is a mathematical method that can map hits in a detector to parameter space to find tracks globally.In this paper,we have used it as the basis for developing a new tracking algorithm to find tracks in MDC.In addition,the drift distances of hits are considered when implementing Hough transform.Results This tracking algorithm is implemented in the BESIII offline software system,and its performance is checked using both Monte Carlo and data.The results show that this tracking method improves reconstruction efficiency at the low transverse momentum region.Conclusions The tracking algorithm based on Hough transform is proved to be beneficial for the MDC low transverse momentum tracking,and has been used in BESIII offline data reconstruction .
基金Ministry of Science & Technology of China (973:2008CB317106)NSFC (10575044, 10635020)Key Projectof Chinese Ministry of Education (306022, IRT0624)
文摘We present a study for matching charged tracks reconstructed from the ALICE tracking detectors with the clusters measured in the photon spectrometer. Matching efficiency and contaminations due to wrong matches have been deduced for charged pions and muons. For electrons, the effect of the material in front of PHOS is discussed.
