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Static interface profiles for contact lines on an elastic membrane with the Willmore energy

Physical Review E 2020年第6期102卷 062803-062803页

作者： Zhen Zhang Jin Yao Weiqing Ren Department of Mathematics Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology (SUSTech) Shenzhen 518055 People's Republic of China Department of Mathematics National University of Singapore Singapore 119076

We consider a fluid interface in contact with an elastic membrane and study the static profiles of the interface and the membrane. Equilibrium conditions are derived by minimizing the total energy of the system with volume constraints. The total energy consists of surface energies and the Willmore energy; the latter penalizes the bending of the membrane. It is found that, while the membrane is locally flat at the contact line with the contact angle satisfying the Young-Dupré equation, the gradient of the mean curvature of the membrane exhibits a jump across the contact line. This jump balances the surface tension of the fluid interface in the normal direction of the membrane. Asymptotic solutions are obtained for two-dimensional systems in the limits as the reduced bending modulus ν tends to +∞ and 0, respectively. In the stiff limit as ν→+∞, the leading-order solution is given by that of a droplet sitting on a rigid substrate with the contact angle satisfying the Young-Dupré equation; in contrast, in the soft limit as ν→0, a transition layer appears near the contact line and the interfaces have constant curvatures in the outer region with apparent contact angles obeying Neumann's law. These solutions are validated by numerical experiments.

关键词： Contact line dynamics Interfacial flows

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Tri-Polarized Holographic MIMO Surface in Near-Field: Channel Modeling and Precoding design

arXiv

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arXiv 2022年

作者： Wei, Li Huang, Chongwen Alexandropoulos, George C. Yang, Zhaohui Yang, Jun Sha, Wei E.I. Zhang, Zhaoyang Debbah, Mérouane Yuen, Chau Pillar Singapore University of Technology and Design 487372 Singapore College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China International Joint Innovation Center Zhejiang University Haining314400 China Hangzhou310027 China The Department of Informatics and Telecommunications National and Kapodistrian University of Athens Panepistimiopolis Ilissia Athens15784 Greece The Technology Innovation Institute Abu Dhabi United Arab Emirates The State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen518055 China Wireless Product R&D Institute ZTE Corporation Shenzhen518057 China The College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China The Technology Innovation Institute Masdar City Abu Dhabi9639 United Arab Emirates CentraleSupelec University Paris-Saclay Gif-sur-Yvette91192 France

This paper investigates the utilization of triple polarization (TP) for multi-user (MU) holographic multiple-input multi-output surface (HMIMOS) wireless communication systems, targeting at capacity boosting and diversity exploitation without enlarging the antenna array sizes. We specifically consider that both the transmitter and receiver are both equipped with an HMIMOS consisting of compact sub-wavelength TP patch antennas within near-field (NF) regime. To characterize TP MU-HMIMOS systems, a TP NF channel model is constructed using the dyadic Green’s function, whose characteristics are leveraged to design two precoding schemes for mitigating the cross-polarization and inter-user interference contributions. Specifically, a user-cluster-based precoding scheme assigns different users to one of three polarizations at the expense of system’s diversity, and a two-layer precoding scheme removes interference using Gaussian elimination method at high computational cost. The theoretical correlation analysis for HMIMOS in NF region is also investigated, revealing that both the spacing of transmit patch antennas and user distance impact transmit correlation factors. Our numerical results show that the users far from transmit HMIMOS experience higher correlation than those closer within NF regime, resulting in a lower channel capacity. Meanwhile, in terms of channel capacity, TP HMIMOS can almost achieve 1.25 times gain compared with dual-polarized HMIMOS, and 3 times compared with conventional HMIMOS. In addition, the proposed two-layer precoding scheme combined with two-layer power allocation realizes a higher spectral efficiency than other schemes without sacrificing diversity. Copyright © 2022, The Authors. All rights reserved.

关键词： Polarization

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Correction to ‘High pressure investigations on neutron irradiated ferroboron’

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Bulletin of Materials science 2023年第1期46卷 1-1页

作者： Kumar, Anand Saha, Uttiyoarnab Radha, E Devan, K Kumar, N R Sanjay Venkiteswaran, C N Divakar, R Shekar, N V Chandra Materials Science Group Indira Gandhi Centre for Atomic Research HBNI Kalpakkam India Reactor Design and Technology Group Indira Gandhi Centre for Atomic Research HBNI Kalpakkam India Reactor Facilities Group Indira Gandhi Centre for Atomic Research HBNI Kalpakkam India Materials and Metallurgy Group Indira Gandhi Centre for Atomic Research HBNI Kalpakkam India

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Multiscale kinetic inviscid flux extracted from a gas-kinetic scheme for simulating incompressible and compressible flows

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Physical Review E 2020年第3期102卷 033310-033310页

作者： Sha Liu Junzhe Cao Chengwen Zhong National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical University Xi'an Shaanxi 710072 China School of Aeronautics Northwestern Polytechnical University Xi'an Shaanxi 710072 China

A kinetic inviscid flux (KIF) is proposed for simulating incompressible and compressible flows. It is constructed based on the direct modeling of multiscale flow behaviors, which is used in the gas-kinetic scheme (GKS), the unified gas-kinetic scheme (UGKS), the discrete unified gas-kinetic scheme (DUGKS), etc. In KIF, the discontinuities (such as the shock wave) that cannot be well resolved by mesh cells are mainly solved by the kinetic flux vector splitting (KFVS) method representing the free transport mechanism (or microscale mechanism), while in other flow regions that are smooth, the flow behavior is solved mainly by the central-scheme-like totally thermalized transport (TTT). The weights of KFVS and TTT in KIF is automatically determined by those in the theory of direct modeling. Two ways of choosing the weights in KIF are proposed, which are actually the weights adopted in the UGKS and the DUGKS, respectively. By using the test cases of the Sod shock tube, the rarefaction wave, the boundary layer of a flat plate, the cavity flow, hypersonic flow over a circular cylinder, the shock and turbulent boundary iteration, and transonic flow over a three-dimensional M6 wing, the validity and accuracy of the present method are examined. The KIF does not suffer from the carbuncle phenomenon, and does not introduce extra numerical viscosity in smooth regions. Especially in the case of hypersonic cylinder, it gives quite sharp and clear density and temperature contours. The KIF can be viewed as an inviscid-viscous splitting version of the GKS. By doing this splitting, it is easy to be used in traditional computational fluid dynamics frameworks. It can also be classified as a type in the numerical schemes based on the kinetic theory that are represented by the works of Sun et al. [Adv. Appl. Math. Mech. 8, 703 (2016)] and Ohwada et al. [J. Comput. Phys. 362, 131 (2018)], except the weights are determined by the weights of direct modeling.

关键词： Aerodynamics Compressible flows High-speed flow Kinetic theory Shock waves

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Boriding of Tungsten by the Powder-Pack Process: Phase Formation, Growth Kinetics and Enhanced Neutron Shielding

SSRN

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SSRN 2022年

作者： Liu, Yue Liu, Xiaoyi Lai, Chen Ma, Jie Meng, Xianfang Zhang, Long Xu, Guanglong Lu, Yiwen Li, Hongyi Wang, Jinshu Chen, Shuqun Key Laboratory of Advanced Functional Materials Education Ministry of China Faculty of Materials and Manufacturing Beijing University of Technology Beijing100124 China Beijing Research Center for Radiation Application Co. Ltd. Beijing Radiation Materials Key Laboratory China Tech Institute for Advanced Materials College of Materials Science and Engineering Nanjing Tech University Nanjing210009 China China Ship Development and Design Center Wuhan430074 China

In this study, high-quality tungsten boride coating was grown on pure tungsten substrate by solid boriding method for improved neutron shielding ability. The microstructure, growth kinetics and radiation shielding performance were systematically studied. It is found that the boronized layer shows a dual-phase structure under the boriding temperature of 950-1050 ℃. The main layer close to coating surface is identified to be the WB phase, while the inner layer adjacent to the substrate is W2B. Thermodynamics calculation proves the W2B is more favored to nucleate and grow adhering to W than α-WB. Once the W2B layer was formed, further increasing boron concentration enables to introduce the formation of WB at the interface. On the basis of the calculated W-B phase diagram, two separated diffusion models were developed to elucidate the growth of WB with composition gradient and W2B with constant composition. The diffusion coefficients of boron in boride phases as well as the activation energy for boron diffusion were estimated. Finally, the large improvement of neutron attenuation ability for tungsten specimen upon boriding treatment was demonstrated. Our findings could provide new directions for developing high performance radiation shielding materials. © 2022, The Authors. All rights reserved.

关键词： Growth kinetics

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Nutrients removal and biomass production from anaerobic digested effluent by microalgae: A review

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International Journal of Agricultural and Biological Engineering 2019年第5期12卷 8-13页

作者： Gang Li Xue Bai Huan Li Zhitao Lu Yuguang Zhou Yingkuan Wang Jinxin Cao Zhigang Huang School of Material Science and Mechanical Engineering Beijing Technology and Business UniversityBeijing 100048China Laboratory of Bioenergy and Environment Science&Technology College of EngineeringChina Agricultural UniversityBeijing 100083China Key Laboratory of Clean Production and Utilization of Renewable Energy Ministry of Agriculture and Rural AffairsBeijing 100083China National Center for International Research of BioEnergy Science and Technology Ministry of Science and TechnologyBeijing 100083China Chinese Academy of Agricultural Engineering Planning and Design Ministry of Agriculture and Rural AffairsBeijing 100125China Inner Mongolia University Hohhot 010070China

This article summarizes the recent progress of nutrient removal from wastewater via *** of nitrogen and phosphorous compounds from wastewater are of great importance,while those compounds are suitable for growth of some microalgae *** a combination provides more opportunities for anaerobic digestion facilities,which are producing large amount of wastewater with high nitrogen and phosphorous ***,in order to optimize and maximize the performance and durability of the nutrient removal process,it is suggested that the basic principles about nitrogen and phosphorous migration should be investigated thoroughly,especially from the fundamentals of substance transfer mechanism between water environment and algal cells.

关键词： microalgae biomass accumulation nutrient removal anaerobic digested effluent(ADE) pollution control

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QuantYOLO: A High-Throughput and Power-Efficient Object Detection Network for Resource and Power Constrained UAVs

QuantYOLO: A High-Throughput and Power-Efficient Object Dete...

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Proceedings of the Digital Image Computing: Technqiues and Applications (DICTA)

作者： Muhammad Gohar Javed Minahil Raza Muhammad Mohsin Ghaffar Christian Weis Norbert Wehn Muhammad Shahzad Faisal Shafait School of Electrical Engineering and Computer Science National University of Sciences and Technology Pakistan Microelectronic Systems Design Research Group Technische Universität Kaiserslautern Germany Deep Learning Laboratory National Center of Artificial Intelligence (NCAI) Pakistan Data Science in Earth Observation TU Munich Germany

Convolutional Neural Networks (CNNs) are producing state-of-the-art results in the object detection field. However, deep topologies of CNN are computationally intensive and typically require excessive resources (i.e. high-end GPUs), which hinder their deployment on resource and power constrained UAVs. In this work, we present a high-throughput and power efficient quantized object detection network, QuantYOLO, which is based on the Tiny-YOLOv2 topology. We conduct a detailed exploration of precision and filter pruning vs. accuracy, throughput and power consumption trade-off for the object detection task. As a result of these explorations, we select a network with binarized weights and 4-bit activations (except the output layer), which is 21.8× smaller than the Tiny-YOLOv2 achieving a mean Average Precision (mAP) of 51.5% on the PASCAL-VOC dataset. Finally, we present an FPGA based accelerator, which achieves 1.6× higher throughput (FPS) and is 3.1× more power efficient as compared to prior FPGA architectures.

关键词： Quantization (signal) Power demand Network topology Object detection Computer architecture Throughput Topology

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Improved atmospheric estimation for aerocapture guidance

Improved atmospheric estimation for aerocapture guidance

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AAS/AIAA Astrodynamics Specialist Conference, 2019

作者： Roelke, Evan Hattis, Phil D. Braun, R.D. The Charles Stark Draper Laboratory Inc. Graduate Research Assistant Entry systems Design Lab Colorado Center for Astrodynamics Research 1111 Engineering Drive BoulderCO80309 United States The Charles Stark Draper Laboratory Inc 555 Technology Square CambridgeMA02139 United States Smead Professor of Space Technology Dean of Engineering and Applied Science 1111 Engineering Drive BoulderCO80309 United States

ISBN: (纸本)9780877036654

Increased interest in Lunar or Mars-sample return missions encourages consideration of innovative orbital operations such as aerocapture, which generally provides significant mass-savings for orbital insertion at Earth or Mars. Drag modulation architectures offer a straightforward approach to orbital apoapsis targeting by enabling ballistic entry, among other benefits. A shortcoming of these architectures is the poor estimation of atmospheric density resulting in target apoapsis altitude errors. This research seeks to assess and improve upon current atmospheric density estimation techniques in order to support the flight viability of discrete event drag modulated aerocapture. Three different estimation techniques are assessed in terms of estimation error and apoapsis altitude error: a static density factor, a density array interpolator, and an ensemble correlation filter. The density interpolator achieves a 5% improvement in median apoapsis altitude over the density factor when entering at –5.9° and targeting a 2000km apoapsis altitude, while the ensemble correlation filter achieves a 7% improvement under identical simulation conditions. The ensemble correlation filter was found to improve with decreasing density search tolerance, achieving a 4:6% improvement in median apoapsis altitude for a tolerance of 1% over 5%. These improvements are dependent on entry and vehicle parameters and improve as the entry angle becomes more shallow or the target apoapsis is reduced. Errors in the density factor measurements are main contributors to the error in estimated versus true density profiles. © 2020, Univelt Inc. All rights reserved.

关键词： Errors

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Analysis of geometric parameters of straight wall three-centered arch and stress of surrounding rock based on conformal mapping

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Yantu Lixue/Rock and Soil Mechanics 2020年 41卷 74-84页

作者： Wu, Su Li, Ke-Gang Wu, Shun-Chuan Wang, Hang-Long Qin, Qing-Ci Li, Ming-Liang He, Fa-Yun Faculty of Land Resources Engineering Kunming University of Science and Technology Kunming650093 China Yunnan Key Laboratory of Sino-German Blue Mining and Utilization of Special Underground Space Kunming650093 China Kunming Prospecting Design Institute of China Nonferrous Metals Industry Co. Ltd. Kunming650051 China

In order to obtain the mapping function with a much higher accuracy, the barrier function algorithm based on the fmincon optimization function is used to solve the mapping function. It is considered that the conformal mapping from the outer boundary of the straight wall three-centered arch to the outer domain of the unit circle can be realized by m = 18 and n = 6, which is superior to the traditional algorithm. Based on the calculation results of analytical solution, the shape effect and size effect caused by the change of geometric parameters of the straight wall three-centered arch tunnel on the surrounding rock stress are analyzed. The results show that the increase rate of stress concentration coefficient in the arc area of the tunnel with small arch width ratio is much larger. The large stress concentration coefficient in the arc area of the tunnel with width-height ratio close to 1 is at the arch shoulder, while the maximum value, which is small, occurs at the corner of the wall. On the contrary, the large stress concentration coefficient in the arc area of the tunnel with width-height ratio far less than 1 is far away from the arch shoulder, while the maximum value is far away from the corner of the wall. When the width-height ratio is equal to 1, the maximum value of stress concentration coefficient appears at the corner, which is approximately the same as that of the stress concentration coefficient at the arch shoulder. © 2020, science Press. All right reserved.

关键词： Conformal mapping

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Research on the measurement of connecting bars'axial force of JUNO central detector

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Radiation Detection technology and Methods 2020年第3期4卷 362-371页

作者： Xiaoyu Yang Lei Yang Wei He Yatian Pei Yuekun Heng Xiaoyan Ma Huafeng Li Kaixi Huang Caishen Wang Yi Li Xiaohui Qian Zhi Wu Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Particle Detection and Electronics Beijing 100049China University of Chinese Academy of Science Beijing 100049China Dongguan University of Technology Dongguan 523808China Beijing Institute of Architectural Design Beijing 100045China

Background The Jiangmen Underground Neutrino Observatory(JUNO)is a multipurpose neutrino experiment designed to determine neutrino mass hierarchy and precisely measure oscillation parameters and study the solar neutrino,supernova neutrino,geo-neutrino,***'s central detector(CD)has 20 kilo-ton liquid scintillator as target mass,which is contained by a huge acrylic sphere with the inner diameter of 35.4 m,and the acrylic sphere is supported by a stainless steel structure through 590 connecting *** Part of the connecting bars bear pull force and the other bars bear push *** is a direct relationship between the stress of connecting bars and that of acrylic *** the installation process of the CD,the pretightening force and axial force of the connecting bars should be monitored with accuracy,and for the filling process and running condition,the precise measurement of axial force can indicate the safety of structure of the *** Statistical method was used to evaluate the performance of measurement schemes,and 4-fiber Bragg grating measurement scheme was determined to be the final scheme,which can get the measurement uncertainty better than 0.7 *** of different measurement schemes are discussed in detail,and some related finite element analysis and evalu-ation method are also introduced in this paper.

关键词： Axial force measuring Mechanical sensor FEA Central detector JUNO

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