厦门大学图书馆声环境研究

随着素质教育的不断深化,国家对高等教育事业给予了越来越大的重视,高校的学习环境相对自由,图书馆作为学生学习的主要场所,其声环境对于学生的学习有重大的影响。文章以厦门大学为主要研究对象,探究其图书馆声环境存在问题,并提出了合理的改善意见

Spindle Thermal Error Comprehensive Prediction Model Based on Information Granulation and SVM

主轴热变形是影响数控机床加工精度的主要因素。为提高主轴热误差的预测精度,提出了基于信息粒化支持向量机（SVM）的主轴热误差综合预测模型。使用信息粒化方法对采样温度数据与主轴热误差数据进行预处理,分别建立基于SVM的主轴热误差的回归预测模型和时间序列模型,通过计算两个模型权重系数,最终建立主轴热误差综合预测模型。以2MZK7150五轴数控可转位刀片工具磨床为研究对象,实验表明,较之于单一模型该模型具有良好的泛化能力和较高建模精度。Spindle thermal deformation has an extraordinary influence on the NC machining precise. Aiming to the im- provement of the spindle thermal deformation predict ability, the spindle thermal error comprehensive predict model is pro- posed on the basis of the information granulation and support vector machine（SVM）. Information granulation method is em- ployed to pretreat the sampling temperature and spindle thermal error. The regression prediction model and time series mod- el of spindle thermal error are also carried out based on the SVM. Finally, the spindle thermal error comprehensive predict model is established using the weight coefficients of the two models. The 2MZK7150 five-axis NC indexable insert tool grinding lathe machining experiment shows that the established model has better generalization ability and higher modeling precision compared with the unitary model.陕西省科技统筹创新工程计划（2014KTD201-04-03

贝壳吸声界面吸声性能试验研究

以贝壳、玻璃棉为主要材料,利用贝壳、玻璃棉、空腔组成一个吸声界面,通过驻波管吸声降噪的试验研究,探究不同厚度的贝壳层、玻璃棉层、空腔这三者的搭配组成的吸声界面的吸声频谱特性及变化规律,用于不同贝壳层厚度、不同玻璃棉厚度吸声性能的预测评估,为最终实现贝壳吸声产品研发提供参考

In situ probing electrified interfacial water structures at atomically flat surfaces using Raman spectroscopy

自然界中水无处不在，人们对水分子的研究已经长达一个多世纪。特别是在材料表面，从原子结构层面理解界面水所发生的各种物理和化学过程，将有利于指导能源和环境领域中开发更好的技术和器件。文献中采用振动光谱已经推知了水在金属界面的不同构型，如四配位水、三配位水、表面特性吸附水、自由水等。然而，仍然缺乏这些界面水在不同电位下清晰的构型图像。李剑锋教授课题组采用不受体相水干扰的表面增强拉曼光谱，首次在金（111）和（100）单晶电极表面上获得了界面水的拉曼信号，并且在析氢反应过程中原位观测到了界面水的两种构型转变。发现界面水随着电位的负移，由“平行”结构向“单端氢朝下”，再向“双端氢朝下”变化。程俊教授课题组采用从头算分子动力学理论方法，模拟出不同电位下，在双电层中界面水的三种构型以及相应的氢键数目，与实验数据很好地吻合，进一步揭示了双电层的原子级结构。该研究首次在实验和理论层面，将界面水的构型转变以及氢键断裂与精确的电极电势标尺进行关联，对探知双电层的三维结构具有指导性意义。 该研究工作通过厦门大学校内合作完成，化学化工学院李剑锋教授和程俊教授为通讯作者，田中群教授提供了重要指导。李超禹博士（现美国麻省理工学院博士后）和乐家波博士（现能源材料化学协同创新中心博士后）为共同第一作者，王耀辉博士生在实验上提供了帮助，物理系的陈舒博士和杨志林教授为本工作开展了电磁场增强计算【Abstract】Molecular structures of solid/liquid interfaces are of fundamental interest, and play significantly in the efficiencies of energy storage and conversion. To elucidate the structures of electric double layers at electrochemical interfaces under bias potentials, we have collaborated in situ Raman spectroscopy and ab initio molecular dynamics, and for the first time distinguished two structural transitions of interfacial water at electrified Au(111) and Au(100) single crystal electrode surfaces. Towards negative potentials, the interfacial water molecules evolve from structurally “parallel” to “one-H-down”, and further to “two-H-down”.Concurrently, the number of hydrogen bonds among the interfacial water shows an overall decrease along with the negative shift of the potential, and undergoes two transitions as well. Our findings shed light on fundamental understanding of electric double layers and electrochemical processes at the interfaces.National Natural Science Foundation of China (Grants No. 21373166, 21522508, 21775127, 21521004, 21321062 and 21621091). 该工作得到国家自然科学基金委的大力资助，也得到了固体表面物理化学国家重点实验室、谱学分析与仪器教育部重点实验室、能源材料化学协同创新中心的支持

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