TiN coating for inner surface modification by grid enhanced plasma source ion implantation

Using the new inner surface modification technique named GEPS II (grid-enhanced plasma source ion implantation), which is designed for inner surface modification of tubular work piece, has successfully produced TiN coating on 0.45% C steel (45 # steel). By comparing with the uncoated 45 # steel sample, the electrochemical corrosion test on the coated 45 # steel samples presents about 5-10 times improvement in their corrosion resistance. Structural analysis shows that the TiN coatings have preferred crystal orientation(111) and (2000). And the depth of coatings is about 20 nm, with part of which embedding in the substrate

Gravitational wave detection by space laser interferometry

为印证广义相对论和开拓引力波天文学窗口,引力波探测是当前国际研究热点.本文围绕空间激光干涉引力波探测,对其科学意义、发展状况、关键技术等进行了回顾.与地面激光干涉引力波探测相比,空间探测的工作频段更低,从10~(-4)~10Hz,在工作距离为百万公里量级上,预计能探测到双致密星系统、超大质量比双黑洞绕转系统、中等质量比双黑洞绕转系统,以及星系合并引起的超大质量黑洞并合等波源.为此,测距精度须达到皮米的量级,并且保证测距技术有效工作的无拖曳航天技术亦有很高的要求.本文以欧洲的空间激光引力波探测计划为例,主要对上述两项技术进行分析和阐述,并展望了空间引力波探测在我国的发展趋势和前景

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