宇宙射线中子法(cosmic ray neutron probe,CRNP)是一种通过监测近地表宇宙射线中子流变化来预测土壤含水量的方法。该方法的突出特点在于百米范围的监测尺度,填补了传统点测量和遥感大范围监测间的尺度空缺,并为中小尺度农田、环境和...宇宙射线中子法(cosmic ray neutron probe,CRNP)是一种通过监测近地表宇宙射线中子流变化来预测土壤含水量的方法。该方法的突出特点在于百米范围的监测尺度,填补了传统点测量和遥感大范围监测间的尺度空缺,并为中小尺度农田、环境和水文等方面研究提供一种新的土壤水监测新技术。在介绍用CRNP法测量土壤含水量基本原理的基础上,分析了该方法测量结果的空间尺度代表性以及大气、土壤和植被等环境因素对其测量结果的影响;综述了近年来该方法在农业管理、水文研究和气象预报等领域的应用进展和动态以及当前研究中存在的问题和今后可能的发展方向。通过对相关研究成果的总结和分析,期望为该技术的深入发展和推广应用提供帮助。展开更多
We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstl...We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero.展开更多
We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM mo...We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM model and the holographic dark energy（HDE） model, to make an analysis. The cosmological observations used in this work include the Planck 2015 CMB temperature and polarization data, the baryon acoustic oscillation data, the type Ia supernova data, the Hubble constant direct measurement data, and the Planck CMB lensing data. We find that, mν,sterileff〈 0.2675 eV and Neff〈 3.5718 for ΛCDM cosmology, mν,sterileff〈 0.5313 eV and Neff〈 3.5008 for wCDM cosmology, and mν,sterileff〈 0.1989 eV and Neff〈 3.6701 for HDE cosmology, from the constraints of the combination of these data. Thus, without the addition of measurements of growth of structure, only upper limits on both mν,sterileff and Neff can be derived, indicating that no evidence of the existence of a sterile neutrino species with e V-scale mass is found in this analysis. Moreover, compared to the ΛCDM model, in the wCDM model the limit on mν,sterileff becomes much looser, but in the HDE model the limit becomes much tighter. Therefore, the dark energy properties could significantly influence the constraint limits of sterile neutrino parameters.展开更多
文摘宇宙射线中子法(cosmic ray neutron probe,CRNP)是一种通过监测近地表宇宙射线中子流变化来预测土壤含水量的方法。该方法的突出特点在于百米范围的监测尺度,填补了传统点测量和遥感大范围监测间的尺度空缺,并为中小尺度农田、环境和水文等方面研究提供一种新的土壤水监测新技术。在介绍用CRNP法测量土壤含水量基本原理的基础上,分析了该方法测量结果的空间尺度代表性以及大气、土壤和植被等环境因素对其测量结果的影响;综述了近年来该方法在农业管理、水文研究和气象预报等领域的应用进展和动态以及当前研究中存在的问题和今后可能的发展方向。通过对相关研究成果的总结和分析,期望为该技术的深入发展和推广应用提供帮助。
文摘We study the mass neutrino interference phase in Schwarzschild-de Sitter space time along the null trajectory and the geodesic line and obtain the effects of cosmological constant A on the neutrino oscillation. Firstly, in the high energy limit, we find that the phase along the geodesic keeps the double of that along the null. Secondly, we calculate the phase on the condition that the cosmological constant, A, is a small quantity. The correction of the phase due to A is given. Finally, we calculate the proper oscillation length in Schwarzschild-de Sitter space-time, which increases because of the existence of A, compared with the result in Schwarzschild space-time. All of our results can be reduced to those in Schwarzschild space-time as A approaches to zero.
基金supported by the National Natural Science Foundation of China(Grant Nos.11522540,and 11690021)the National Program for Support of Top-notch Young Professionalsthe Provincial Department of Education of Liaoning(Grant No.L2012087)
文摘We investigate how the dark energy properties change the cosmological limits on sterile neutrino parameters by using recent cosmological observations. We consider the simplest dynamical dark energy models, the wCDM model and the holographic dark energy（HDE） model, to make an analysis. The cosmological observations used in this work include the Planck 2015 CMB temperature and polarization data, the baryon acoustic oscillation data, the type Ia supernova data, the Hubble constant direct measurement data, and the Planck CMB lensing data. We find that, mν,sterileff〈 0.2675 eV and Neff〈 3.5718 for ΛCDM cosmology, mν,sterileff〈 0.5313 eV and Neff〈 3.5008 for wCDM cosmology, and mν,sterileff〈 0.1989 eV and Neff〈 3.6701 for HDE cosmology, from the constraints of the combination of these data. Thus, without the addition of measurements of growth of structure, only upper limits on both mν,sterileff and Neff can be derived, indicating that no evidence of the existence of a sterile neutrino species with e V-scale mass is found in this analysis. Moreover, compared to the ΛCDM model, in the wCDM model the limit on mν,sterileff becomes much looser, but in the HDE model the limit becomes much tighter. Therefore, the dark energy properties could significantly influence the constraint limits of sterile neutrino parameters.
