课程文献中心 更多>>

摘要： This report consists of two parts. Firstly, an introduction to neutrino oscillations is presented. This includes introducing neutrino mass terms into the standard model, the leptonic mixing matrix, neutrino oscillations in vacuum and neutrino oscillations in matter. Furthermore, the concept of scalar non-standard interactions is introduced and how neutrino oscillations are altered by them. Secondly, scalar non-standard interactions are investigated in the context of the ESSnuSB experiment. The investigation is done using the GLoBES software package. With it we investigate the effects of scalar non-standard interaction on the probability curves, we check the sensitivity of the scalar non-standard interaction parameters at ESSnuSB, with which we can determine the expected three sigma range of ESSnuSB for the real diagonal SNSI parameters. Finally we look at the main question this report is investigating, which is how the SNSI parameters affect the ability for ESSnuSB to claim charge-parity violation. We find that SNSI can have a significant effect on the ability for ESSnuSB to claim charge-parity violation in the lepton sector. For certain values of the SNSI parameters, delta CP is suppressed in the oscillation probability, resulting in a drastic worsening of this ability.

摘要： In the last decade or so, the CKM anomaly has appeared as a 3σ deviation of the first row of the CKM matrix from the SM prediction of unitarity. In this thesis, I investigate the impact of three separate NP models on the CKM anomaly. The first two models consist of adding either right-handed or pseudoscalar currents in the quark sector of the low-energy Lagrangian of the electroweak SM, while the third is a 3 + 1 sterile neutrino model with sterile mass in the MeV- range. Fitting the models with additional quark currents to the experimental data results in an improved agreement between theory and experiment, especially for the right-handed currents model: that brings the minimum χ 2 down from its SM value of 24.60 by ∆χ 2 = 18.05, while the pseudoscalar currents ∆χ 2 is 4.73. A proposed direction for further research is to add both right- handed and pseudoscalar currents. As for the 3+1 sterile neutrino model, there is no improvement in the fit for sterile masses between 34 MeV and 1 GeV. However, choosing a sterile mass m 4 of 1 or 17 MeV leads to a ∆χ 2 of 7.66 and 7.33, at a mixing angle |U e4 | of 0.0393[70] and 0.0419[82], respectively. To my knowledge, these are the first results about lower MeV-range sterile neutrinos in relation to the CKM anomaly. The sterile minimum at 1 MeV is not excluded by the current constraints in the (|U eN | 2, m N )-plane, while that at 17 MeV is. Interesting next steps could be to explore the sterile mass range below 1 MeV – possibly leading to relatively unconstrained regions of the (|U µN | 2, m N )-plane – and also to go beyond this simple 3+1 model to e. g. 3+2 or νSMEFT models.

关键词： 实验教学   原子吸收光谱实验   数据处理  

摘要： 原子吸收光谱(AAS)实验是仪器分析和工科分析化学教学中必开设的实验课.常规开设的AAS实验包括用标准曲线(标准加入)法测定组成简单(复杂)样品中的金属离子.不管使用哪一种方法都需要待测元素标准系列溶液的配制、其吸光度的测定和实验数据的处理.AAS实验目的是让学生掌握AAS仪的使用方法、提高实验技能和处理实验数据的能力,同时密切结合课堂教学,提高教学效果.一般因实验数据处理由仪器工作站完成,既存在学生对数据处理方法理解不透,又存在教师对学生操作技能和实验结果的评价缺乏数据支撑等问题.在AAS实验教学中,尝试引入偏差计算概念,让学生独立处理AAS实验数据,掌握实验数据的简便处理方法,既有利于学生独立处理实验数据和巩固理论课中的相关知识点,又有利于教师评价AAS实验结果.

关键词： 铋试金   黑色页岩   金   铂   钯   石墨炉原子吸收光谱法(GF-AAS)   氧化铋   硝酸钾  

摘要： 黑色页岩中Au、Pt和Pd含量较低且分布不均匀，因此测定时需要辅以合适的分离富集方法。本文通过矿物解离度分析仪研究了黑色页岩样品的组成结构；利用Ag能与Au、Pt和Pd形成合金的原理，以Bi2O3作为捕集剂，在试金配方中添加Ag作为保护剂进行熔融，增加了铋扣的稳定性；同时在试金配料中加入KNO3以将基体中的S氧化成硫酸盐进入熔渣；得到的铋扣经过灰吹可得到银合粒，据此，实现了对黑色页岩中Au、Pt和Pd的分离富集。采用先加入HNO3再加入HCl的方式溶解银合粒，建立了石墨炉原子吸收光谱法（GF-AAS）测定黑色页岩中Au、Pt和Pd的方法。对试金配料中面粉和Bi2O3的用量进行了优化，确定采用8 g面粉和100 g Bi2O3。试验表明，在试金配方中加入200μL 20 g/L Ag银标准溶液，在Bi完全吹尽后，形成的银合粒形状规则、光滑圆整、大小适中，未出现散珠现象。在选定的实验条件下，用Au、Pt和Pd的吸光度与其对应的质量浓度绘制校准曲线，决定系数为0.999 7～0.999 9,特征浓度为0.338～2.15 ng/mL。将实验方法应用于黑色页岩贵金属成分分析标准物质中Au、Pt和Pd的测定，测定值与认定值基本一致。按照实验方法对贵州省纳雍地区的黑色页岩样品进行精密度和加标回收试验，测定结果的相对标准偏差（RSD,n=6）在3.1%～5.1%之间，加标回收率在92%～109%之间。

摘要： The KM3NeT collaboration is constructing two water-Cherenkov neutrino detectors in the Mediterranean sea. While one of the detectors is optimized for astrophysical research, the other is optimized for neutrino oscillations research. The latter detector is called ORCA and its main goals are to unravel the neutrino mass ordering and put world-leading constraints on the measurement of the sin 2 θ 23 and?∆m 2 31?? oscillation parameters. Although the detector is still under construction, with only 18 of the total 115 planned detection units deployed, it is already collecting data that can be used to perform neutrino oscillation research. To this end, the MONA software package was developed to model the expected event distributions as a function of the oscillation parameters and the observables, which are the reconstructed energy and direction of the neutrino. This thesis presents several improvements that were made to the model in the MONA software package, mostly concerning the usage of MC event weights and the implementation of nuisance parameters. In addition, an analysis of neutrino oscillations with 510 days of data collected by six detection units of the ORCA detector is presented using the improved model. Although this dataset does not have sufficient statistics to be sensitive to the neutrino mass ordering with relevant significance, the oscillation parameters are measured to be sin 2 θ 23 = 0.513 +0.054 −0.055 (stat) ±0.005 (sys) and?∆m 2 31?? = 2.16 +0.37 −0.15 (stat) ±0.28 (sys) [10 −3 eV 2 ]. The systematics involved in this measurement are also investigated in this thesis.

摘要： 近日,华北地区持续高温,河北涞源1000 千伏岳定双回特高压线路接续金具发现安全隐患,国家电网出动直升飞机,首次采用X射线检测作业,耗时 50分钟.在确保输电线路不停电的状态下,完成了对线路隐患点的检修作业任务,成功排除了隐患,有效保障了迎峰度夏期间京津冀地区电力供应.

摘要： Gunpowder is an ancient multipurpose invention from 9$^{th}$ century in China. The chemical composition and physical structure of gunpowder have been developed for centuries to fulfill many purposes which lead into the development of smokeless powder or propellants. Knowledge about the chemistry surrounding propellant is vastly studied and known but precise study of the interior structure of individual propellant grains are lacking. This study validates X-ray microtomography as a method to analyse the inner physical structures of propellant grains from 18 different batches. I measured two grains from each batch. My focus of interest was on interior material domain identification, their sizes, porosity, pore sizes and the correlation of these with the recipe of the propellant. To aid my analysis I used a Python script and batch specific recipes for almost all of the batches provided by Nammo Vihtavuori Oy. Particles identified from the images are nitrocellulose, potassium bitartrate, potassium sulfate, surface finishing compound and two metals: tin and bismuth. Identified components do not change their original grain like shape while inside propellant and their size is also preserved. However, variations inside the batches are high, resulting in different sized particles and pores in varying locations for each grain. Potassium nitrate salt had the only notable correlation to the inner structure of propellant grains: the more there was salt the higher the porosity and thinner the walls between the pores are. Unfortunately, large variations in the atomic number of component elements introduced artifacts into the images, and high variations between grains prevented me from gathering statistically relevant data. Nevertheless, imaging of propellant with X-ray tomography (X-CT) has proven useful giving lots of previously unknown information of the physical structure of propellant grains and their composition, which can be used to develop new improvements to propellant. Met

关键词： 铜精矿   汞   氧弹燃烧   原子荧光光谱法(AFS)  

摘要： 汞是铜精矿中主要有害元素之一，铜精矿中汞的准确测定具有重要意义。称取0.10 g样品，以0.50 g苯甲酸为助燃剂通过氧弹燃烧法分解样品，挥发逸出的汞被酸性高锰酸钾溶液吸收后用原子荧光光谱法进行测定，建立了氧弹燃烧分解-原子荧光光谱法(AFS)测定铜精矿中汞含量的分析方法。在选定的实验条件下，汞质量浓度在0～2.0 ng/mL范围内与其对应的荧光强度线性良好，相关系数为0.999 9。方法检出限为12 ng/g,定量限为40 ng/g。按照实验方法对3个不同汞含量的铜精矿标准物质进行7次平行测定，同时在样品中加入汞标准溶液进行加标回收试验，结果的相对标准偏差(RSD,n=7)为2.1%～5.8%,回收率为90%～107%。选取来自智利、澳大利亚、墨西哥、秘鲁、老挝、西班牙6个地区的铜精矿样品，分别采用实验方法和国家标准GB/T 3884.20—2018中的固体进样直接测汞法进行方法对照，t检验结果表明，这两种方法无统计学意义上的差异。