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Design and development of radio frequency output window for circular electron–positron collider klystron

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Chinese Physics B 2018年第11期27卷 620-625页

作者：陆志军 Shigeki Fukuda 周祖圣裴士伦王盛昌肖欧正 UnNisa Zaib 白博文裴国玺董东周宁闯王少哲池云龙 Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China High Energy Accelerator Research Organization KEK Oho Ibaraki 305-0801 Japan GLVAC Industrial Technology Research Institute of High Power Devices Kunshan 215300 China

This paper presents the first phase of design, analysis, and simulation for the klystron coaxial radio frequency（RF）output window. This study is motivated by 800 kW continuous wave（CW）, 650 MHz klystrons for the future plan of circular electron–positron collider（CEPC） project. The RF window which is used in the klystron output section has a function to separate the klystron from the inner vacuum side to the outside, and high RF power propagates through the window with small power dissipation. Therefore, the window is a key component for the high power klystron. However, it is vulnerable to the high thermal stress and multipacting, so this paper presents the window design and analysis for these problems. The microwave design has been performed by using the computer simulation technology（CST） microwave studio and the return loss of the window has been established to be less than-90 d B. The multipacting simulation of the window has been carried out using MultiPac and CST particles studio. Through the multipacting analysis, it is shown that with thin coating of TiN, the multipacting effect has been suppressed effectively on the ceramic surface. The thermal analysis is carried out using ANSYS code and the temperature of alumina ceramic is lower than 310 K with water cooling.The design result successfully meets the requirement of the CEPC 650 MHz klystron. The manufacturing and high power test plan are also described in this paper.

关键词： klystron coaxial radio frequency window thermal stress multipacting

Icosahedral quasicrystals solids with an elliptic hole under uniform heat flow

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Chinese Physics B 2014年第5期23卷 397-403页

作者：李联和刘官厅 College of Mathematics Science Inner Mongolia Normal University College of Physical Science and Technology Inner Mongolia University Inner Mongolia Key Laboratory of Nanoscience and Nanotechnology

The complex variable method for solving the two-dimensional thermal stress problem of icosahedral quasicrystals is stated. The closed-form solutions for icosahedral quasicrystals containing an elliptical hole subjected to a remote uniform heat flow are obtained. When the hole degenerates into a crack, the explicit solutions for the stress intensity factors is presented.

关键词： icosahedral quasicrystals thermal stress elliptic hole stress intensity factors

Electrical conductivity changes of bulk tin and Sn-3.0Ag-0.5Cu in bulk and in joints during isothermal aging

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International Journal of Minerals,Metallurgy and Materials 2010年第4期17卷 453-458页

作者： Bin Liu Fu Guo Institute of Building Environment and Energy Efficiency China Academy of Building Research Beijing 100044 China College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

The changes of electrical conductivity （resistance） between Sn-3.0Ag-0.5Cu solder joints and printed circuit board （PCB） assembly during aging at 125℃ were investigated by the four-point probe technique. The microstructural characterizations of interfacial layers between the solder matrix and the substrate were examined by optical microscopy and scanning electronic microscopy. Different types of specimens were designed to consider several factors. The experimental results indicate that electrical conductivities （resistances） and residual shear strengths of the solder joint specimens significantly decrease after 1000 h during isothermal aging. Microcracks generate in the solder matrix at the first 250 h. Besides, the evolutions of microstructural characterizations at the interface and the matrix of solder joints were noted in this research.

关键词： lead-free solder electrical conductivity isothermal aging, microcrack thermal stress

一种用于船舶汽轮机的安全且经济的启动加速概念

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哈尔滨工程大学学报（英文版） 2023年第2期22卷 381-394页

作者： Mateusz Bryk Jerzy Głuch Energy Conversion Department The Szewalski Institute of Fluid-Flow-Machinery PASGdańsk 80-231Poland Department of Control and Power Engineering Faculty of Mechanical Engineering and Ship TechnologyGdansk University of TechnologyGdańskPoland

This paper analyses the issue of accelerated start-up of a marine steam turbine,which is an important problem because the start-up of a steam machine involves the combustion of fuel that is not transformed into useful energy.To find novel technologies that offer improvements in this aspect is essential due to restrictions on reducing ship emissions.Thus,the shorter the start-up time,the better for the environment and economy.High-pressure(HP)part of the turbine originally located on the Queen Elizabeth II unit was analysed.Advanced numerical calculations by thermal fluid-solid-interaction(thermal FSI)were carried out.A series of simulations were performed for the accelerated start-up with controlled steam injection.A description of the chosen calculation methodology and the results obtained by simulation are included in this paper.The stress occurring during the accelerated start-up are approximately 40 MPa higher than those during the reference start-up.The relative elongations between the rotor and the hull during accelerated start-up reach a maximum value of 0.89 mm(0.83 mm for ultra-fast start-up).Reducing the steam turbine start-up time by 75%results in a 36.7 tons reduction in fuel consumption for start-up,resulting in an annual savings of 5372 USD.In conclusion,the concept proposed by the authors is safe,less expensive and does not affect the life of the turbine.In addition,results and applications from Siemens prove that additional injection of cooling steam is possible.

关键词： Marine steam turbine start-up Ultra-fast start-up thermal stress Relative elongations Fuel savings Energy management

thermal stressES ANALYSIS OF CERAMIC/METAL FUNCTIONALLY GRADIENT MATERIAL CYLINDER

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Applied Mathematics and Mechanics(English Edition) 1999年第4期20卷 74-78页

作者：吕运冰张开银肖金生温冬生

In this paper, the composite cylinder system is made of three layers: metal, functionally gradient material (FGM) and ceramics is studied. The formulas of the steady_state temperature distribution and the associate thermal stress distribution in the cylinder are obtained. For ZrO 2/Ti_6Al_4V system, the distribution of steady_state temperature and thermal stress are calculated and discussed.

关键词： functionally gradient material thermal stress cylinder

Engineering measures for preventing upheaval buckling of buried submarine pipelines

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Applied Mathematics and Mechanics(English Edition) 2012年第6期33卷 781-796页

作者：刘润王武刚闫澍旺吴新利 State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University School of Engineering Design Pennsylvania State University

In-service hydrocarbons must be transported at high temperature and high pressure to ease the flow and to prevent the solidification of the wax fraction. The high temperature and high pressure will induce the additional stress in the pipeline, which results in the upheaval buckling of the pipeline. If such expansion is resisted, e.g., by the frictional effects of the foundation soil over a kilometer or of a pipeline, the compressive axial stress will be set up in the pipe-wall. When the stress exceeds the constraint of the foundation soil on the pipeline, suddenly-deforming will occur to release the internal stress, similar to the sudden deformation of the strut due to stability problems. The upheaval buckling may jeopardize the structural integrity of the pipeline. Therefore, effective engineering measures against this phenomenon play an important role in the submarine pipeline design. In terms of the pipeline installation and protection measures commonly used in Bohai Gulf, three engineering measures are investigated in great details. An analytical method is introduced and developed to consider the protection effect of the anti-upheaval buckling of the pipeline. The analysis results show that the amplitude of the initial imperfection has a great effect on the pipeline thermal upheaval buckling. Both trenching and burial and discrete dumping are effective techniques in preventing the pipeline from buckling. The initial imperfection and operation conditions of the pipelines determine the covered depth and the number of layers of the protection measures.

关键词： submarine buried pipeline thermal stress upheaval buckling protectionmeasure

Theoretical modelling and experimental study of novel photothermal microactuators

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Chinese Optics Letters 2009年第8期7卷 694-698页

作者：马利红张冬仙刘超章海军 State Key Laboratory of Modern Optical Instrumentation Zhejiang University Information Optical Institute Zhejiang Normal University

We present a category of novel photothermal （PT） microactuators. Each microactuator consists of two PT arms that are jointed at the free end and connected to an anchor at the fixed end. When a laser beam irradiates one of the arms （called hot arm, and the other is cold arm）, light energy is absorbed and converted into heat. The asymmetric thermal expansion of the hot and cold arms results in lateral deflection. Based on conduction heat transfer theory and heat dissipation mechanism, we study the PT effects and establish the theoretical model of PT expansion for the microactuators. The temperature distribution and the linear thermal expansion can be numerically calculated. The analytical solution provides an insight into the operation of the actuators and predicts the performance of the actuators with new designs. A symmetry microactuator and a microswitch as the prototypes have been fabricated and tested. The experimental results are in good agreement with the theoretical predictions and prove the feasibility of the novel PT microactuators.

关键词： Heat conduction Microactuators Phototransistors thermal stress

Thermomechanical analysis of nodule damage in HfO_2/SiO_2 multilayer coatings

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Chinese Optics Letters 2011年第10期9卷 82-85页

作者：单永光贺洪波魏朝阳王营赵元安 Key Laboratory of High-Power Laser Materials Shanghai Institute of Optics and Fine MechanicsChinese Academy of Science Graduate University of Chinese Academy of Sciences

Samples with nodular defects grown from gold nanoparticles are prepared, and laser-induced damage tests are conducted on them. Nodular defects, which are in critical state of damage, are cross-sectioned by focusing on the ion beam and by imaging using a field emission scanning electron microscope. The crosssectional profile shows that cracks are generated and propagated along the nodular boundaries and the HfO2/SiO2 interface, or are even melted. The thermomechanical process induced by the heated seed region is analyzed based on the calculations of temperature increase and thermal stress. The numerical results give the critical temperature of the seed region and the thermal stress for crack generation, irradiated with threshold fluence. The numerical results are in good agreement with the experimental ones.

关键词： Cracks Critical current density (superconductivity) Hafnium oxides Scanning electron microscopy thermal stress

A Banding Structure in a Ni-Cu-Si Cast Alloy

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Journal of Materials Science & Technology 2008年第5期24卷 813-815页

作者： Qi ZHENG Yufeng ZHENG Hongyu ZHANG Xiaofeng SUN Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China University of Science and Technology of China Hefei 230026 China

The solidified microstructure of a Ni-Cu-Si cast alloy has been investigated, and a kind of banding structure was observed. The results showed that, the banding structure was composed of coarser particles which were Ni3Si type of precipitates and similar to the fine particles precipitate uniformly distributed within matrix of Ni solid solution, in both crystal structure and composition. The formation of bandings was resulted from cast thermal stress and dislocation walls. It was found that the cracks propagated along these bandings in tensile test. The banding structure can be depressed by reducing the cast thermal stress, which can improve the tensile ductility.

关键词： Ni-Cu-Si cast alloy Banding structure Solidification thermal stress