利用表面增强拉曼光谱快速鉴别卷烟生产中烟用香精香料

烟用香精香料的配方是卷烟工业中的核心技术,也是构建不同特色卷烟产品的关键之一。然而,现有的香精香料质量评价手段主要是人工嗅香和测定某些特定的物性指标,如折光指数、相对密度、酸值、挥发份总量等。在实验室科研中还有使用色谱-质谱联用等方法。但是上述手段仍存在较多问题,比如受主观意识影响,操作繁琐,前处理耗时长,费用高,灵敏度低等。基于此,本文开发了一种利用表面增强拉曼光谱技术结合主成分分析算法来快速鉴别实际生产中不同种类、不同掺兑样的烟用香精香料的方法。本文利用该方法成功获取不同种类、同一种类不同生产批次及烟用香精香料不同掺兑量样品的增强拉曼谱图。经主成分分析表明不同种类以及不同掺兑量样品的散点分布在不同区域,直接区分度高;同一种类不同生产批次的香精香料谱图类似,在散点图中较为集中;说明不同生产批次的样品以及不同掺兑量的样品都可以与其他种类的香精香料标准样品进行有效区分。本文利用表面增强拉曼光谱结合主成分分析算法对烟用香精香料进行检测的方法操作简易,检测快捷,成本低廉,结果便于分析识别,适用于烟用香精香料实际生产中的质量控制。国家自然科学基金(No.21522508)浙江中烟工业有限责任公司科技项目(No.ZJZY2016C002

雾化NdFeB合金粉末的组织结构与磁性能

用８ＭＰａ的Ａｒ气雾化制取ＮｄＦｅＢ合金粉末，光学金相观察和Ｘ射线衍射分析表明，粉末主要由Ｎｄ２Ｆｅ１４Ｂ相组成。粉末具有一定的矫顽力，回火处理后矫顽力明显提高。不同粒度的粉末矫顽力存在差异，粉末越细其矫顽力越高。粉末初始磁化曲线与烧结ＮｄＦｅＢ磁体相似

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