Strategy use is correlated with the students＇ performance, so it is necessary to provide students with some strategy instruction. In order to make the strategy instruction more pertinent to the students＇ needs, this...Strategy use is correlated with the students＇ performance, so it is necessary to provide students with some strategy instruction. In order to make the strategy instruction more pertinent to the students＇ needs, this study has investigated the status quo of the listening strategy use among the non-English major postgraduates, and has discovered that the students＇ use of listening strategy was far from sufficient, especially in management strategies and social strategies.展开更多
The 21 cm intensity mapping(IM)technique provides us with an efficient way to observe the cosmic large-scale structure(LSS).From the LSS data,one can use the baryon acoustic oscillation and redshift space distortion t...The 21 cm intensity mapping(IM)technique provides us with an efficient way to observe the cosmic large-scale structure(LSS).From the LSS data,one can use the baryon acoustic oscillation and redshift space distortion to trace the expansion and growth history of the universe,and thus measure the dark energy parameters.In this paper,we make a forecast for cosmological parameter estimation with the synergy of three 21 cm IM experiments.Specifically,we adopt a novel joint survey strategy,FAST(0<z<0.35)+SKA1-MID(0.35<z<0.8)+HIRAX(0.8<z<2.5),to measure dark energy.We simulate the 21 cm IM observations under the assumption of excellent foreground removal.We find that the synergy of three experiments could place quite tight constraints on cosmological parameters.For example,it providesσ(?m)=0.0039 andσ(H0)=0.27 km s^(-1) Mpc^(-1) in theΛCDM model.Notably,the synergy could break the cosmological parameter degeneracies when constraining the dynamical dark energy models.Concretely,the joint observation offersσ(w)=0.019 in the wCDM model,andσ(w0)=0.085 andσ(wa)=0.32 in the w0waCDM model.These results are better than or equal to those given by CMB+BAO+SN.In addition,when the foreground removal efficiency is relatively low,the strategy still performs well.Therefore,the 21 cm IM joint survey strategy is promising and worth pursuing.展开更多
文摘Strategy use is correlated with the students＇ performance, so it is necessary to provide students with some strategy instruction. In order to make the strategy instruction more pertinent to the students＇ needs, this study has investigated the status quo of the listening strategy use among the non-English major postgraduates, and has discovered that the students＇ use of listening strategy was far from sufficient, especially in management strategies and social strategies.
基金supported by the National SKA Program of China(Grant Nos.2022SKA0110200,and 2022SKA0110203)National Natural Science Foundation of China(Grant Nos.11975072,11835009,and 11875102)。
文摘The 21 cm intensity mapping(IM)technique provides us with an efficient way to observe the cosmic large-scale structure(LSS).From the LSS data,one can use the baryon acoustic oscillation and redshift space distortion to trace the expansion and growth history of the universe,and thus measure the dark energy parameters.In this paper,we make a forecast for cosmological parameter estimation with the synergy of three 21 cm IM experiments.Specifically,we adopt a novel joint survey strategy,FAST(0<z<0.35)+SKA1-MID(0.35<z<0.8)+HIRAX(0.8<z<2.5),to measure dark energy.We simulate the 21 cm IM observations under the assumption of excellent foreground removal.We find that the synergy of three experiments could place quite tight constraints on cosmological parameters.For example,it providesσ(?m)=0.0039 andσ(H0)=0.27 km s^(-1) Mpc^(-1) in theΛCDM model.Notably,the synergy could break the cosmological parameter degeneracies when constraining the dynamical dark energy models.Concretely,the joint observation offersσ(w)=0.019 in the wCDM model,andσ(w0)=0.085 andσ(wa)=0.32 in the w0waCDM model.These results are better than or equal to those given by CMB+BAO+SN.In addition,when the foreground removal efficiency is relatively low,the strategy still performs well.Therefore,the 21 cm IM joint survey strategy is promising and worth pursuing.
