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Low Profile Microsrip Antenna with Broadside Radiation Patterns and Low Cross Polarizations

Journal of Physics: Conference Series 2019年第3期1237卷 032036-032036页

作者： Lai, Ping Xu, Chao Xu, Zhuo Luo, Kang Unit.32382 of PLA Wuhan Hubei 430311 China China Fire Rescue College Beijing Province 102230 China Comprehensive Information Guarantolice Corps Nanning Guangxi 530308 China National Key Laboratory of Science and Technology on Vessel Integrated Power System University Wuhan Hubei 430030 China

A low profile microstrip antenna with adjustable bandwidth around 3 GHz is proposed. The compact antenna consists of a square patch with a square aperture to tune the resonance center frequency. The input impedance bandwidth is about 2.67% with stable gain around 3.2 dBi. Besides, the 3-dB beam width is about 100°. Both the side-fed and bottom-fed modes are analyzed. According to the simulation, good broadside radiation patterns with low cross polarizations are observed in the two principal planes. The detailed design considerations are described and discussed while the surface current distribution and radiation characteristics are analyzed. This design is suitable for mobile wireless communication.

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Thick SU8 microstructures prepared by broadband UV lithography and the applications in MEMS devices

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Optoelectronics Letters 2016年第3期12卷 182-187页

作者：李东玲温志渝尚正国佘引 National Key Laboratory of Fundamental Science of Novel Micro/Nano Device and System Technology Key Laboratory of Optoelectronic Technology and System of the Education Ministry of China Micro System Reaserch CenterChongqing University

Thick SU8 microstructures with high aspect ratio and good side wall quality were fabricated by ultraviolet （UV） lithography, and the processing parameters were comprehensively studied. It proves that the adhesion of SU8 on silicon （Si） substrates is influenced by Si-OH on the surface, and can be improved by the HF treatment. Cracks and de- lamination are caused by large internal stress during fabrication process, and are significantly influenced by soft bake and post-exposure bake processes. The internal stress is reduced by a low post-exposure bake exposure tem- perature of 85 ℃ for 40 rain. A three-step soft bake enhances the reflowing ofSU8 photoresist, and results in uni- form surface and less air bubbles. The vertical side wall is obtained with the optimized exposure dose of 800 mJ/cm2 for the thickness of 160 μm. Using the optimized fabrication process combined with a proper structure design, dense SU8 micro pillars are achieved with the aspect ratio of 10 and the taper angle of 89.86°. Finally, some possible ap- plications of SU8 in micro-electromechanical system （MEMS） device are developed and demonstrated.

关键词： MEMS器件紫外光刻微结构应用微机电系统烘烤过程编写宽带

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The preliminary performance study of ATF with M3 fuel and Zr-4 cladding 24

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2016 24th International Conference on Nuclear Engineering, ICONE 2016

作者： Chunyu, Yin Teng, Tu Tang, Changbing Jiao, Yongjun Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China ChengduSichuan China

ISBN: (纸本)9780791850015

Metal matrix microencapsulated (M3) fuel is one of the research directions on Accident Tolerant Fuel (ATF). In this article, it provides one of ATF design which consists of BISO (Bistructural ISOtropic) particles embedded in a zirconium alloy matrix, and the cladding coating with silicon carbon (SiC). The temperature distribution of the ATF element has been built, and then the center temperature has also been calculated based on the operation parameters of the large-scale pressurized-water reactor. Simultaneity, the several factors of fuel failure is preliminary analyzed and calculated, especially the pressure shell failure mechanism. Copyright © 2016 by ASME.

关键词： Metallic matrix composites

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Neutronic feasibility analysis of fully ceramic microencapsulated fuel for commercial PWRs

Neutronic feasibility analysis of fully ceramic microencapsu...

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Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance

作者： Mancang, Li Dan, Wang Yingrui, Yu Dong, Qin Wenjie, Li Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

ISBN: (纸本)9780894487309

The fully ceramic microencapsulated (FCM) fuel is based on tristructural isotropic (TRISO) coated particles embedded in silicon carbide (SiC) matrix, which is among the accident tolerant fuel concept options. With the strength of high fission product retention, the FCM fuel provides potential superior safety performance. Compared to the conventional standard UO2 fuel, the deficiency of FCM fuel is its considerable lower fissile inventory, which results in a reduced reactor power or/and life. Supposing the FCM fuel is used as direct replacement of the fuel in commercial PWRs, the spectrum is softened due to the usage of SiC as matrix, and the moderator temperature coefficient is possible to be positive at the beginning of life, leading to high risk during operation. A neutronic feasibility study of FCM fuel utilized in commercial PWRs is performed in the paper. The fuel enrichment and undermoderated lattice are evaluated by analyzing the typical TRISO particle with UO2 kernels which is widely used in high temperature gas reactors and that with enlarged UN fuel kernels. It was found that under the mandatory constraint of low enriched uranium, the FCM fuel with UO2 kernels, although relatively mature, is only capable of small reactor designs, and the assembly lattice needs to be modified. The FCM fuel with UN kernels, when directly loading in the commercial PWRs, can yield comparable reactor power and life;however, a higher fuel enrichment and the fuel design and fabrication need to be optimized.

关键词： Silicon carbide

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Investigation on contact angle of ball bearings

Investigation on contact angle of ball bearings

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作者： Wang, Fengtao Jing, Minqing Fan, Hongwei Wei, Yaobing Zhao, Yang Liu, Heng State Key Lab for Strength and Vibration of Mechanical Structures Xi'An Jiaotong University Xi'an China Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'An Jiaotong University No. 28Xianning West Road Xi'an Shaanxi710049 China School of Mechanical and Electrical Engineering Lanzhou University of Technology Lanzhou China School of Mechanical Engineering Xi'An University of Science and Technology Xi'an China

As an important structure parameter, contact angle is also a judgement factor for the working performance of ball bearings. However, under some conditions, the ball may roll over the raceway shoulder, and contact angle is not enough for estimating this phenomenon. Thus, edge angle and edge distance are proposed as compensatory judgement factors in the current study. A six-degree dynamic model with time-varying contact stiffness was developed for investigating effects of initial contact angle, raceway groove curvature factors, number of balls, axial load, shaft speed, friction coefficient and raceway misalignment on contact angle, contact stiffness, edge angle and edge distance. Inapposite initial contact angle may make the ball roller over the raceway shoulder, inner raceway misalignment have significant influences on the stable motion of ball bearings, and more harmonics frequencies about contact angle appear. Comparison of contact angle from presented model with Jones-Harris model under axial load shows reasonable qualitative agreement. © IMechE 2016.

关键词： Contact angle

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Unexpectedly high salt accumulation inside carbon nanotubes soaked in very dilute salt solutions

arXiv

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arXiv 2018年

作者： Wang, Xueliang Shi, Guosheng Liang, Shanshan Liu, Jian Li, Deyuan Fang, Gang Liu, Renduo Yan, Long Fang, Haiping Center for Thorium Molten Salt Reactor System Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Division of Interfacial Water Key Laboratory of Interfacial Physics and Technology and Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China University of Chinese Academy of Sciences Beijing100049 China Shanghai Applied Radiation Institute Department of Physics Shanghai University Shanghai200444 China School of Physical Science and Technology ShanghaiTech University Shanghai201210 China

We experimentally demonstrate the formation of salt aggregations with unexpectedly high concentration inside multi-walled carbon nanotubes (CNTs) soaked only in dilute salt solutions and even in solutions containing only traces of salts. This finding suggests the blocking of fluid across CNTs by the salt aggregations when CNTs are soaked in a dilute salt solution with the concentration of seawater or even lower, which may open new avenues for the development of novel CNT-based desalination techniques. The high salt accumulation of CNTs also provides a new CNT-based strategy for the collection/extraction of noble metal salts in solutions containing traces of noble metal salts. Theoretical analyses reveal that this high salt accumulation inside CNTs can be mainly attributed to the strong hydrated cation–π interactions of hydrated cations and π electrons in the aromatic rings of CNTs. Copyright © 2018, The Authors. All rights reserved.

关键词： Hydration

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Bottom Reflooding Experiments in a Thin Rectangular Channel

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Energy Procedia 2017年 127卷 335-342页

作者： Wei Xu Jun Yao Jianye Ji Xiaojing Liu Xu Cheng Wei Zeng Hongxing Yu School of Nuclear Science and Engineering Shang Hai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 P.R.China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Cheng Du 610041 P.R.China

Experiments were carried out to study the thermal hydraulic behaviors in a narrow rectangular channel under bottom reflooding conditions. The channel is formed between a stainless steel heating plate and a transparent heatproof glass and dimensions of the channel are 600 mm in height, 60 mm in width and 4 mm of gap thickness. All the parameters (such as initial wall temperature, inlet velocity and systematic pressure) affect the heat transfer features during quenching process. The experimental results illustrate that for a given initial surface temperature, rewetting velocity increases with the increasing flow rate and increasing systematic pressure, while it decreases with the increasing initial surface temperature. With different flow rate and system pressure, the rewetting temperature is almost the same, but it varies when initial surface temperature is different.

关键词： Bottom reflooding Rectangular channel Heat tranfer

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Policy Optimization for Content Push via Energy Harvesting Small Cells in Heterogeneous Networks

Policy Optimization for Content Push via Energy Harvesting S...

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作者： Gong, Jie Zhou, Sheng Zhou, Zhenyu Niu, Zhisheng School of Data and Computer Science Sun Yat-sen University Guangzhou510006 China Tsinghua National Laboratory for Information Science and Technology Department of Electronic Engineering Tsinghua University Beijing100084 China State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Electrical and Electronic Engineering North China Electric Power University Beijing102206 China

Motivated by the rapid development of energy harvesting technology and content-aware communication in access networks, this paper considers the push mechanism design in small-cell base stations (SBSs) powered by renewable energy. A user request can be satisfied by either push or unicast from the SBS. If the SBS cannot handle the request, the user is blocked by the SBS and is served by the macro-cell BS instead, which typically consumes more energy. We aim to minimize the ratio of user requests blocked by the SBS to total number of user requests. With finite battery capacity, Markov decision process-based problem is formulated, and the optimal policy is found by dynamic programming (DP). Two threshold-based policies are proposed: the push-only threshold-based policy and the energy-efficient threshold-based policy, and the closed-form blocking probabilities with infinite battery capacity are derived. Numerical results show that the proposed policies outperform the conventional non-push policy if the content popularity changes slowly or the content request generating rate is high, and can achieve the performance of the greedy optimal threshold-based policy. In addition, the performance gap between the threshold-based policies and the DP optimal policy is small when the energy arrival rate is low or the request generating rate is high. © 2016 IEEE.

关键词： Heterogeneous networks

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Failure Analysis of Power Electronic Devices and Their Applications under Extreme Conditions

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Chinese Journal of Electrical Engineering 2016年第1期2卷 91-100页

作者： Yifei Luo Fei Xiao Bo Wang Binli Liu National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of EngineeringWuhan430033China

Power electronic devices are the core components of modern power converters,not only for normal applications,but also for extreme *** design of power electronic devices require large redundancies for *** results in huge volume and weight for a large-capacity power converter,especially for some extreme ***,to optimize the power density,the reliability of power devices needs to be investigated first in order to obtain the accurate operational margin of a power *** much research on device failure analysis has been reported,there still lacks efficient failure evaluation *** paper first summarizes the current failure ***,a three-step failure analysis method of power electronic devices is proposed as:failure information collection,failure identification and mechanism,and failure *** physics-based modeling method is emphasized since it has a strong relationship with the device *** that,power electronic device applications under extreme conditions are introduced and a design method of device under extreme conditions is proposed based on the thermal equilibrium ***,the challenges and prospects to improve the power device reliability under extreme conditions are concluded.

关键词： Power electronic device failure mechanism failure evaluation physics-based modeling extreme conditions thermal equilibrium

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A preliminary study on irradiation growth behavior modelling of N36 zirconium alloy tube

A preliminary study on irradiation growth behavior modelling...

引用

Top Fuel 2016: LWR Fuels with Enhanced Safety and Performance

作者： Yifei, Miao Yongjun, Jiao Kun, Zhang Shuo, Xing Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Nuclear Power Institute of China China

ISBN: (纸本)9780894487309

As a new kind of Zr-Sn-Nb series alloy, N36 has not been explored in irradiation growth behavior before. In this paper, four empirical correlations including power, logarithmic, exponential and hyperbolic tangent law were used to build irradiation growth model of N36 zirconium alloy preliminarily. Before that, lengths of the fuel rods with N36 claddings from poolside measurement were analyzed to get irradiation growth strains, which were then used to fit the four empirical correlations mentioned above. Distribution of fast fluence along axial direction of tubes was considered in all irradiation growth models. The fitting results showed that the hyperbolic tangent law fit irradiation growth strains the best, while power law did the worst. In order to improve the precision of the hyperbolic tangent model, several improvements were done. Verification and validation of the improved hyperbolic tangent irradiation growth model suggested that the size of second phase may have an influence on irradiation growth behavior of N36 tubes.

关键词： Zirconium alloys

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