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摘要： This thesis deals with issue of thermonuclear fusion reaction and deals with the development of temperature and radiation resistant Hall sensors to be placed in the ITER fusion reactor. It investigates differenet configutations of Hall sensor geometry, orientation and data acquisition and compares the measured data in these configurations.

摘要： The large magnetic fields of neutron stars and produced in heavy-ion collisions motivate investigation into the response of strongly-interacting matter to extreme magnetic forces beyond just theoretical interest. Furthermore, the varying temperature T, baryon chemical potential μB, and aforementioned magnetic fields B, of these systems leads to questions concerning the phase structure of Quantum Chromodynamics (QCD) at large. At low temperatures, superconducting phases become a possible candidate for the ground state in the μB-B plane. This thesis investigates two scenarios where these phases emerge at T=0, with an emphasis on the type-II regime. The first scenario concerns type-II superconductivity at large μB. At asymptotically high baryon density the ground state of QCD is a colour superconductor where gluonic fields can experience a Meissner effect. In the two-flavour pairing (2SC) and colour-flavour locked (CFL) colour-superconducting phases, a small admixture of the photon with a gluon is also expelled which means an applied external magnetic field will experience a slight Meissner effect. Therefore, these phases act as very weak electromagnetic superconductors. Previous works have shown that with massless quarks the type-II 2SC phase is preferred in a certain parameter region where the magnetic defects are domain walls. We introduce corrections for a finite strange quark mass in a Ginzburg-Landau approach, and find that the domain wall defects are replaced by a cascade of multi-winding flux tubes, among other changes to the phase diagram. Due to the emergence of a second colour-superconducting condensate emerging in the core, the magnetic flux is confined into "rings'' where both condensates are depleted, forming pipe-like structures. In the second scenario, μB is low enough such that the presence of nucleons is not yet energetically favourable. It was previously shown that, using Chiral Perturbation Theory and incorporating the chiral anomaly via a Wess-Zumi

标准号: YY/T 1766.3-2023

摘要： 本文件规定了X射线计算机体层摄影设备（以下简称CT扫描装置）进行双能量成像以及能谱应用的性能评价方法。 本文件适用于全身及专用CT扫描装置，包括为放射治疗计划提供图像数据的CT扫描装置，但不包括口腔CT扫描装置或具有三维成像功能的血管造影及移动C形臂设备。

摘要： Amorphous Selenium is a direct conversion photoconductor that has been widely used in X-ray imaging applications. Due to its high spatial resolution A-Se plays an important role in breast cancer screening and diagnostics, allowing for the detection of small and subtle lesions. However, a-Se has poor collection efficiency due to low carrier mobility and charge trapping resulting from its amorphous structure. The trapped charges can cause memory artifacts, including photocurrent lag, which can persist for several seconds after the X-ray pulse has ended. As a result, a-Se is a challenging material for dynamic imaging applications that require high spatial resolution. The research discussed in this thesis aims to investigate and address the temporal behavior of a-Se photoconductors, specifically the issue of lag, which can lead to image artifacts and degradation of image quality in dynamic imaging applications. The research involves the design of unipolar charge sensing detectors with pixel sizes of 20, 40, 80 and 150 microns to improve energy resolution and the temporal response compared to conventional a-Se detectors. Theoretical analysis and simulations are presented for the unipolar charge sensing detector including weighting potential, charge collection efficiency, pulse height spectroscopy and energy resolution which range from 5% to 2%. The work further discusses the fabrication process of the designed detector in the G2N lab at the university of Waterloo. It discusses the experimental results obtained and the challenges that were faced while fabricating the detector and how they can be overcome in the future.

摘要： This thesis aims to improve the accuracy of re-entry epoch prediction for decaying satellites in orbit. It explores the impact of aerodynamic coefficients, rotational dynamics, and initial state uncertainties on re-entry prediction. By using SPARTA software, the study generates aerodynamic coefficients and considers factors such as object shape, attitude, atmospheric density, and relative velocity. The findings emphasize the importance of precise aerodynamic modelling, particularly the inclusion of lift force for specific shapes like Starlink satellites. Rotational dynamics reduce the range of re-entry epoch predictions by narrowing the average drag coefficient. Initial state uncertainties have a limited effect compared to the average drag coefficient. The research also evaluates the re-entry prediction for a Starlink satellite, aligning closely with existing models after applying a correction factor. Recommendations include sensitivity analyses and investigating different satellite shapes to enhance prediction capabilities. These findings ensure more reliable and accurate re-entry epoch predictions for impact analysis.

摘要： Generative models have improved massively in the recent years, and this hascreated a need for automatic validation techniques for synthetic data. In this master's thesisa method for validating synthetic images based on feature extraction and cluster analysis istested on X-ray images created with generative adversarial networks. The results show thatthe generated images follow the distribution of the imageset used in training, but are clearlydistinct from a different X-ray imageset.

关键词： 陶瓷燃料颗粒   内聚力单元法   动态开裂   裂变气体  

摘要： 陶瓷燃料在高燃耗条件下产生大量裂变气孔，气孔中释放至裂纹空腔的裂变气体对裂纹扩展行为具有较大的影响。本文开发了一种变内压作用下的裂纹动态扩展模型，实现了裂纹空腔内压与裂纹扩展过程相互耦合作用的动态开裂技术。内压大小随裂纹扩展而变化，同时开裂行为受内压大小的影响。并将此模型成功应用于高燃耗结构陶瓷燃料颗粒内的开裂行为模拟，研究了裂变气体释放对裂纹扩展的力学作用。基于全局内聚力单元模拟了裂纹产生和扩展过程，建立了气体释放对裂纹扩展力学作用的研究方法，分析了气体压力对燃料颗粒内部裂纹产生和扩展过程的影响。结果表明，气体总量不变情况下气体释放至裂纹空腔会基于气体压力和裂纹几何特征对裂纹扩展产生抑制的效果。对于不同气体初始压力的情况，气体初始压力越大，止裂时裂纹扩展长度越长。本文开发的动态裂纹模拟技术为精确研究弥散型燃料芯体失效提供了分析方法及数值参考，也为载荷与裂纹扩展相耦合的情况提供一种研究方法。

标准号: DB43/T 2637-2023

摘要： This thesis explores four research projects in particle physics that aims in enhancing our understanding of the universe's fundamental particles and forces. The first part examines the Georgi-Machacek (GM) model, which expands the Standard Model (SM) scalar sector by including two SU(2) L triplets. We conduct a comprehensive analysis of the experimental status of this model. Our findings establish an experimental lower limit on the triplet vacuum expectation value that affects deviations from the SM in the Higgs boson's tree-level couplings. The second part explores breaking CP in a dark sector consisting of SM gauge singlets. We conduct a two-loop calculation in the effective theory, with the dark sector interacting with the SM sector via a vector Z 0 portal and Higgs portal. Our findings demonstrate that collider constraints from B-factories exclude feasible baryo- genesis for Z 0 masses under 10 GeV. Additionally, future electron-positron Higgs fac- tories may test the viable baryogenesis parameter space. The third part examines the Sommerfeld enhancement for scattering ampli- tudes. We create a straightforward method to remove divergences in the narrow- width approximation, which applies in the near-threshold region and considers only the resonant contribution. Our approach offers a good approximation for the exact outcome and has the potential for exploring dark matter models featuring unstable states. Lastly, we investigate generating neutrino masses from the gravitational θ anomaly. The neutrino condensate's primary renormalizable interactions restrict the possibility of producing hierarchical masses compatible with observation, even when accounting for SM loop corrections. Higher-dimensional operators can alleviate this issue. We examine the potential of new particles to create neutrino mass splittings. Our find- ings indicate that new particles altering the scalar potential of the condensate or appearing in loops for the neutrino self-energy can solve this

摘要： In this work a method was developed allowing for the simultaneous measurement of species concentration-, temperature-, and X-ray absorption or X-ray diffraction profiles through a fixed-bed reactor using synchrotron radiation. The method provides a comprehensive insight into catalytic reactors under operation, promoting an efficient and sustainable optimization of catalytic processes in the future. The strengths of the method were demonstrated by studying the oxidative dehydrogenation of ethane over supported molybdenum oxide catalysts, revealing the interplay between local reaction conditions and catalyst structure.