Precision Measuring Platform Design and Implementation for Measurement of Large-size Optical Elements

随着光学元件的设计与制造技术的发展，目前光学元件，特别是大尺寸光学元件已经广泛应用在航空、航天、国防等各个行业中，因此对大尺寸光学元件的加工与检测提出了更高的要求，精密检测技术也成为近几十年来世界各国研究的重点。 精密检测技术是精密加工技术发展的基础和先决条件之一，而精密检测平台是实现精密检测的保障。精密检测平台的开发与设计包含了系统结构的设计与完成、系统的调试以及系统误差的检定等诸多方面的内容；开发了光学元件检测系统软件，可以针对不同的光学元件规划不同的检测路径，对检测所得的数据进行分析处理获取元件的实际面形参数，并与给定的元件理论面形参数进行比较，评定光学元件的表面加工质量。 本文针对...With the development of the optical components design and manufacturing technology, optical lens especially large-size optical lens have been widely used in aviation, aerospace, national defense and etc, so the processing and measurement of optical components have become the research focus in today’s word, and this also put forward higher requirements of precision metrical technology. Precisi...学位：工学硕士院系专业：物理与机电工程学院机电工程系_精密仪器及机械学号：1992007115116

浅析化学技术在污水处理中的运用

&lt;div style="left: 165.173px; top: 267.237px; font-size: 13.3333px; font-family: serif; transform: scaleX(1.0305);" data-canvas-width="777.0000000000006"&gt;我国目前还要经过很长的一段社会生产结构改革和生产技术创新的发展阶段，随着人们对社会生产生活环境质量水平的要求的提高，&lt;/div&gt;&lt;div style="left: 85.0393px; top: 287.237px; font-size: 13.3333px; font-family: serif; transform: scaleX(1.03813);" data-canvas-width="850.2266666666662"&gt;绿色环保、减少污染物的问题排放必然要放到社会生产生活的首要位置上了。化学技术在污水处理中发展前景广阔，不仅能够实现污水达标排放&lt;/div&gt;&lt;div style="left: 85.0393px; top: 307.237px; font-size: 13.3333px; font-family: serif; transform: scaleX(1.03863);" data-canvas-width="850.6400000000009"&gt;的目标，而且还可以通过对污水的回收利用来节约企业生产成本。因此，有关部门应当重视化学技术在污水处理中的运用，不断研究创新、推广&lt;/div&gt;&lt;div style="left: 85.0393px; top: 327.237px; font-size: 13.3333px; font-family: serif; transform: scaleX(1.02564);" data-canvas-width="293.3333333333333"&gt;应用这一系列一化学技术，为环保事业做出贡献。&lt;/div&gt;</jats:p

求解非平底一维浅水方程的KFVS格式

以 Boltzmann方程為基礎 ,本文提出了求解非平底淺水方程的 KFVS(Kinetic FluxVector Splitting)格式。因通量計算中考慮了底坡項的作用 ,計算方法和諧 ,即在非平底靜水計算中始終能保持流速為零 ,水位為常數。數值試驗表明 ,無論是計算恒定流還是非恒定流 ,該方法具有健全性和高分辨率等特點. This paper presents a kinetic flux vector splitting (KFVS) scheme for the shallow water equations with source terms. Due to the appropriate implementation of the source term effect in the flux evaluation, the current scheme is a well balanced method. The scheme is accurate and robust for both steady and unsteady flow simulations

三角形网格下求解二维浅水方程的KFVS格式

以Boltzmann方程為基礎,建立了求解二維淺水方程的KFVS(Kinetic Flux Vector Splitting)格式。為保證計算格式的和諧性,通量計算中考慮了底坡源項的作用。在此基礎上,采用特殊的底坡源項處理技術,建立了三角形網格下二階精度的KFVS和諧格式。經典型算例和錢塘江涌潮計算驗證,證明本文提出的方法分辨率高,邊界適應性強,并具有模擬間斷流動的能力。Based on the Boltzman equation, the kinetic flux vector splitting (KFVS) scheme for solving 2-D shallow water equations with triangular mesh is developed. In order to establish a well-balanced scheme, the source term effect is taken into account explicitly in the flux evaluation. On this basis, a special technique for dealing with source term due to bottom topography is adopted and the well-balanced KFVS scheme with triangular mesh possessing second order accuracy is established. The validity of the proposed method is verified by the comparison of calculation result of a traditional typical example with the field observation data of a tidal bore in Qiantang River

On Power Enhancement and Polarized Light GaN-based Light Emitting Diodes Encompassed with Nanorods

自1990年後，p型氮化鎵發展完備，氮化鎵目前廣泛的被應用在發光二極體上。發光二極體具有反應時間短，可靠度高，元件壽命長，低耗電等優點。近幾年來，發光二極體廣泛地應用在液晶螢幕的背光模組。由於氮化鎵與空氣的折射係數差異，其介面處將會發生全反射，並使得光萃取效率降低。另一方面，現今業界將極化片放置於背光源以及液晶螢幕之間藉此達成極化光緣，但極化片將會使通過的光強度降低一半以上。因此，發光二極體仍有許多有趣的議題值得探討，例如，偏極化光緣的達成以及光萃取率的增加。 在本篇文章中，藉由塗佈自組排列的單層二氧化矽奈米小球做為蝕刻遮罩以製作自組性奈米柱陣列，並圍繞於發光二極體方型發光區，這種奈米小球自然微影技術不需增加額外光罩，所以製作成本低廉，為一種非常有發展潛力的奈米結構製作技術。我們證明此種自組排列的奈米柱陣列可以收集發光二極體內被量子井侷限之側向傳遞光。由光強度對電流作圖，可以得知，有20微米、密度為0.21的奈米柱陣列圍繞之氮化鎵發光二極體，其於15毫安培的電流注入下，將會有40%的光強度增加。由於隨機排列的奈米柱造成各向等性的光散射，各角度的光強度皆上升。 延續上個實驗，接下來我們提出一個新穎的低成本方法來提升發光二極體的光極化比例以及光萃取效率－將手指狀的p型發光區圍繞以自然微影製作的自組排列奈米柱陣列；由於奈米柱排列方向垂直於p型極化光的電場振動方向，所以奈米柱陣列對p型極化光的布拉格繞射效果比s型極化光大，故有奈米柱陣列圍繞的發光二極體，其極化比例高於沒有奈米柱陣列圍繞的元件。在發光二極體的正上方量測，有奈米柱陣列圍繞的元件，其p型極化光為s型極化光的1.96倍；若是將00到900的光強度積分起來，將得到p型極化光為s型極化光的1.52倍。Since p-type GaN is well developed in 1990’s, GaN has been widely used in light emitting diodes. There are several advantages such as short response time, good reliability, long life time, and low power consumption for GaN light emitting diodes. In recent year, the demands of light emitting diodes such as backlight module increased dramatically. Since the refraction index is different between GaN and air, total reflection which decreases low external quantum efficiency causes at the interface. On the other hand, the commercial method to get polarized light is place polarizer between the backlight and liquid crystal. This method will leads light intensity decay at least 50% when light passes through the polarizer. Therefore, there are interesting topics of LEDs such as getting a polarized light source and improving the light extraction efficiency. In my thesis, by spin-coating a monolayer of self-aligned SiO2 nanosphere as the etching mask, nanorods array which encompassed with square shape light emitting mesa are fabricated. Since no additional lithography-mask needs by using the nanoparticle natural lithography, it has well potential to fabricate the low-cost nanostructure. We demonstrate a method of utilizing self-assembled nanorods array to collect the laterally propagating guided modes from a light emitting diode (LED). We measure a light intensity enhancement factor of 40% from GaN-based LEDs encompassed with 20μm thick nanorods array which filling factor is 0.21. Such power enhancement is found to be omni-directional due to a broken symmetry from a randomized distribution of the nanorods array placed along the periphery of the LED’s mesa. These observations indicate that the use of nanorods array can efficiently redirect the propagation of the laterally guided modes to the surface normal direction. Continuing from the previous experiment, we provide a noval and low-cost method by using nanorods to get polarized light source and enhance the output power of light emitting diodes－finger shape p-mase encompassed with self-aligned nanorods array by using natural lithography. Since the bragg diffraction of laterally propagated p-polarized mode by nanorods is more efficient than the s-polarized light, the p/s ratio of the device with nanorods is higher than that without rods. The polarization behavior of the light emitting diodes with and without nanorods surrounding the p-mesa is investigated. In my research, the p/s ratio of the LED with nanorods is 1.96 at 90˚, and is 1.52 when the integrating intensity between 0˚ and 90˚ is considered.Table of contents文口試委員審定書誌要bstracthapter.1 Introduction-1 Preface ……………………………………………………………………1-2 Motivation…………..……………….……………………………………3hapter.2 Historical review-1. Nanostructure LEDs devices ………………………………………….....5-2. Polarized LEDs device ……………………………………….……….....7-3. Nanorod fabrication process ……………………………………………10-4. Nanosphere self-align lithography………………………………….......12eference ………….………………………………………………..……….17hapter.3 InGaN/GaN MQW LEDs with square shape mesa encompassed with nanorods array-1. InGaN/GaN MQW LEDs sample structure…………………….….……23-2. Device fabrication process……………………………………..….……25-3. Characteristic discussion………………………………………………..35hapter.4 InGaN/GaN MQW LEDs with finger shape mesa encompassed with nanorods array-1. Device fabrication process……………………………………….….….43-2. Characteristic discussion……………………………………………….49eference ………….……………………………………….………………..54hapter.5 Conclusion 5-1 Conclusion ……………………………………………………………...5

高階氣體動理學格式在湍流數值模擬中的應用

本文回顧了高階氣體動理學格式在湍流數值模擬中的應用。與傳統的Riemann求解器相比,氣體動理學格式可以提供時空耦合的演化過程,這對發展高精度格式十分重要。因此,基于兩步四階時間離散和高精度WENO重構,發展了具有四階時間精度的氣體動理學格式。該格式有更高的數值精度和穩定性,并且具有更好的處理復雜流動問題的能力。目前,兩步四階格式已經成功地應用到低雷諾數湍流直接數值模擬和高雷諾數工程湍流RANS模擬中,包括低速槽道湍流、超聲速均勻各向同性衰減湍流、二維亞聲速翼型湍流和三維跨聲速翼身湍流等。數值結果表明該格式對湍流直接數值模擬和湍流RANS模擬具有高數值精度和高數值穩定性。下一步將利用高階氣體動理學格式研究更具有挑戰性的可壓縮湍流問題,例如超聲速湍流邊界層和激波邊界相互作用等。 We review the application of high-order gas-kinetic scheme (HGKS) in the numerical simulations of turbulence. HGKS was developed based on the two-stage fourth-order temporal discretization and high-order weighted essentially non-oscillation (WENO) reconstruction. Compared with the classical Riemann solvers, the high-order temporal evolution process, which is extremely helpful in the design of robust, accurate, and efficient higher-order schemes, can be used to construct a spatial-temporal coupled gas-kinetic flux solver. Currently, HGKS has been successfully applied in the direct numerical simulations and Reynolds averaged Navier-Stokes (RANS) simulations of turbulence, including low-speed turbulent channel flows, the decaying supersonic isotropic turbulence, the subsonic NACA0012 airfoil turbulence, and the transonic ARA M100 wing-body turbulence. The numerical results show that HGKS has the high accuracy and outstanding robustness for turbulence simulations. In summary, the HGKS provides a powerful computational tool for studying turbulent flows, especially for compressible turbulence. In the future, more challenging studies will be conducted, including the supersonic turbulent boundary layers and the shock-boundary layer interaction. © 2021, The Editorial Board of Acta Aerodynamica Sinica. All right reserved

An Exploration of the Influence Factors on Tourism Experience Memory:A Research Based on Tourism in China

随着体验经济时代的带来,旅游体验的重要性也越发凸显。而在旅游结束后,如何让游客对这种体验有深刻和生动的记忆则是尚未被重视的问题,这种关于体验的记忆将会影响旅游者对旅游目的地的满意度以及未来旅游地的选择决策。文章对在中国旅游情景下影响旅游体验记忆的因素进行探索,尝试去填补有关旅游体验记忆两要素再现性和生动性之间关系研究的空白。通过对国内5大旅游城市的问卷调查,共回收有效问卷748份,并利用结构方程模型进行了验证。结果表明:愉悦感、新奇感和参与感对旅游体验记忆的再现性有显著的正向影响,其中,愉悦感的影响最大,新奇感次之,参与感最小;只有特色化对旅游体验记忆的生动性有显著的正向影响;同时,旅游体验记忆的再现性对生动性也有正向显著影响。Tourist experience is more and more important in the tourism industry. Traditional tourism industry, which is merely targeted at providing tourism products, can no longer meet the demand of tourists. It has been known that tourism experience has a significant effect on the satisfaction of tourists. Meanwhile, such experiences will be kept as memory in the mind of tourists, and that memory will have an influence on tourists' future decision.However, there is rare research focus on the exploration of the factors which affect the tourism experience memory. Meanwhile, the relationship between the two dimensions of tourism experience memory, recollection and vividness, is still not clear. This paper tries to explore the factors influencing the formation of tourism experience memory in the context of China tourist,and figure out the relationship between recollection and vividness.Based on the literature review we propose our research model. We choose hedonism, novelty,involvement and local culture as the main factors influencing tourism experience memory. In the meanwhile, we suggest that the recollection of tourism experience memory has a significant on vividness. We collect questionnaires from tourists in five cities and received 748 valid questionnaires. We use structural equation model to conduct our empirical analysis.Conclusions: 1) Hedonism, novelty and involvement have a positive effect on the recollection of tourism experience memory; among them hedonism has the strongest influence. This result indicates that, a tourism experience with strong hedonism, novelty and involvement can make tourist recollect this memory more easily. 2)Local culture has a positive influence on the vividness of the tourism experience memory. Vivid tourism experiences can make the tourism experience memory more vital.3) Recollection of tourism experience memory has a positive influence on vividness. This indicates that a vivid tourism experience memory is based on the recall of the overall tourism process

南秦岭早古生代地层含硒量及硒的分布规律

本文对南秦岭大巴山区主要分布的早古生代地层各种岩石的含硒量的研究结果表明,含硒量与岩石的岩性和形成时代密切相关,与岩石的含碳量和含硫量成正线性关系。碳质板岩和石煤相对于其他类岩石的含硒量高,碳质板岩一般为6×10~(-6)～35×10~(-6),石煤的含硒量为8×10~(-6)～45×10~(-6);中、下寒武统和志留系大贵坪组的碳质板岩和石煤含硒量较高,可达30×10~(-6)。同时,下寒武统的含硒量远远大于早古生代其他层位同类岩石的平均含硒量,是同类岩石平均含量的5～10倍。如碳酸盐岩的含硒量为2×10~(-6)～4×10~(-6);细粒岩石的含硒量较粗粒岩石的含硒量高,下志留统陡山沟组的厚层状到中厚层状砂岩、粉砂岩和上寒武统的砾屑灰岩的含硒量相近,约0.05×10~(-6)～0.08×10~(-6),是本区最低的。因此,并非本区所有岩石都富硒