一种磁性纳米粒子及其制备方法和应用

本发明涉及一种磁性纳米粒子及其制备方法和应用。具体地，所述磁性纳米粒子具有下组特征：1)所述磁性纳米粒子为铁氧体；2)所述磁性纳米粒子的粒径为0.1-30nm；3)所述磁性纳米粒子的弛豫率r1≥1.2mM-1s-1；4)所述磁性纳米粒子的驰豫率比r2-r1≤3.5且r2-r1≥1.05；5)0.5mM所述磁性纳米粒子的T1加权信号强度≥70。本发明还公开了所述磁性纳米粒子的制备方法和应用。将所述磁性纳米粒子应用于磁共振成像中可获得一种成像性能显著优异、磁敏感性高且T1信号丰富的优质MRI造影剂，可提高其对肿瘤、心脑血管等重大疾病的发现与检出，从而显著降低医学检测和治疗成本

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies