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The effect of thickness reduction on microstructure, mechanical, and damping properties of Mg-1.0wt% Ca alloy

Materials Today Communications 2025年 47卷

作者： Xinyu Liu Youping Sun Wangzhen Li Huashen Liu Jiangmei He Mengyu Pei Huabin Lu College of Mechanical and Automotive Engineering Guangxi University of Science and Technology Liuzhou 545006 China Guangxi Key Laboratory of Automobile Components and Vehicle Technology Liuzhou 545006 China Guangxi Earthmoving Machinery Collaborative Innovation Center Liuzhou 545006 China Engineering Research Center of Advanced Design and Manufacturing Technology of Heavy Vehicle Components Ministry of Education Guangxi University of Science and Technology Liuzhou 545006 China

This paper investigates the effects of varying rolling and reduction ratios on the mechanical properties and damping characteristics of Mg-1.0 wt% Ca alloys. The study revealed that as the thickness reduction increased, the grain size progressively decreased, the internal dislocation density of the alloy increased, the percentage of large-angle grain boundaries rose, and both the ultimate tensile strength and elongation of the alloy improved. Under 80 % reduction, X-ray diffraction (XRD) analysis indicates that the intensity ratio of the (0002) basal peak to the (10−11) prismatic peak is 2.66. This suggests an enhanced preferred orientation of the alloy grains, resulting in improved texture strength. At this stage, the tensile strength is measured at 217.26 MPa, the yield strength at 186.92 MPa, and the elongation is 7.59 %, indicating satisfactory mechanical performance. A basal texture was observed within the alloy, and the dislocations were composed of cylindrical  , conical  , and conical  types. The room-temperature damping exhibited a P 3 damping peak across various thickness reductions, with the alloy showing the most excellent room-temperature damping at a 50 % thickness reduction, achieving a damping value ( Q −1 ) of 0.034. For a given thickness reduction, the damping performance of the alloy decreased with increasing frequency. Conversely, for a fixed frequency, the damping performance improved with increased thickness reduction.

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Segmented metal-strip magnetic-field probe with high electric-field suppression ratio 6

Segmented metal-strip magnetic-field probe with high electri...

引用

6th IEEE Global Electromagnetic Compatibility Conference, GEMCCon 2020

作者： Peng, Zhihe Yang, Jingxian Chen, Junfeng Xiao, Long Wang, Songcen Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design Center Wuhan China China Electric Power Research Institute Electrical Engineering and New Material Department Beijing100192 China

ISBN: (纸本)9781728184630

Magnetic-field probes can be used to measure the strength of magnetic field because of their ability to couple magnetic-field energy. The main probe performances include sensitivity, spatial resolution, electric-field suppression ratio (EFSR), measurement accuracy, bandwidth, etc. Those performances can be improved by changing the size and structure of the probe. In this paper, a segmented metal-strip magnetic-field probe is proposed for high EFSR. The proposed segmented metal-strip magnetic-field probe adds four layers of segmented metal strips on the head of the stripline probe, which changes the probe's topology. It weak the electric-field interference while maintaining the magnetic-field signal. The proposed segmented metal-strip magnetic-field probe are designed under Printed Circuit Board (PCB) process. Simulation results show that when the frequency is 10GHz, the EFSR of the proposed probe is 4.85dB higher than that of the reference probe. © 2020 IEEE.

关键词： Probes

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Topological Hall Effect Driven by Short-Range Magnetic Orders in EuZn2As2

arXiv

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arXiv 2022年

作者： Yi, Enkui Zheng, Dong Feng Pan, Feihao Zhang, Hongxia Wang, Bin Chen, Bowen Wu, Detong Liang, Huili Mei, Zeng Xia Wu, Hao Yang, Shengyuan A. Cheng, Peng Wang, Meng Shen, Bing Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of Physics Sun Yat-Sen University Guangdong Guangzhou510275 China State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University Guangdong Guangzhou510275 China Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China Laboratory for Neutron Scattering Beijing Key Laboratory of Optoelectronic Functional Materials and MicroNano Devices Department of Physics Renmin University of China Beijing100872 China Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore487372 Singapore

Short-range (SR) magnetic orders such as magnetic glass orders or fluctuations in a quantum system usually host exotic states or critical behaviors. As the long-range (LR) magnetic orders, SR magnetic orders can also break time-reversal symmetry and drive the non-zero Berry curvature leading to novel transport properties. In this work, we report that in EuZn2As2 compound, besides the LR A-type antiferromagnetic (AF) order, the SR magnetic order is observed in a wide temperature region. The magnetization measurements and electron spin resonance (ESR) measurements reveal the ferromagnetic (FM) correlations for this SR magnetic order which results in an obvious anomalous Hall effect above the AF transition. Moreover the ESR results reveal that this FM SR order coexists with LR AF order exhibiting anisotropic magnetic correlations below the AF transition. The interactions of LR and SR magnetism evolving with temperature and field can host non-zero spin charility and berry curvature leading the additional topological Hall contribution even in a centrosymmetric simple AF system. Our results indicate that EuZn2As2 is a fertile platform to investigate exotic magnetic and electronic states. Copyright © 2022, The Authors. All rights reserved.

关键词： Magnetic moments

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Construction and Deformation Method of 3d Model Based on Rubik's Snake

SSRN

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SSRN 2022年

作者： Zhang, Yuxiao Wang, Jin Zhang, Dongliang Lu, Guodong Chen, Long State Key laboratory of Fluid Power & Mechatronic Systems Zhejiang University Hangzhou310027 China Engineering Research Center for Design Engineering and Digital Twin of Zhejiang Province China College of Computer Science Zhejiang University Hangzhou310058 China School of Mechanical Engineering University of Shanghai for Science and Technology Shanghai200093 China

Rubik's Snake is an intellectual toy with a high degree of freedom, which can be changed and combined freely. This paper proposes a method for constructing and deforming 3D models, which can construct the 3D model into a Rubik's Snake configuration and realize the mutual deformation between different configurations with a straight chain as the intermediate state through standard folding steps. A detailed representation of the voxels of the 3D model is presented. Based on the refined voxels, a connection forest generation algorithm is developed, which is able to describe possible Rubik's Snake configurations. The foldability verification of the configuration and the generation of the folding sequence are realized by the folding rules. In addition, a collision detection algorithm based on encoding and projection is introduced to detect collisions in the process of generating folding sequences. In order to achieve mutual deformation between 3D models, the number of modules in their chain configuration is matched and adjusted. In this paper, an interactive platform is established, which enables users to calculate the deformation of the input model through simple operations, and obtain a simulation animation of the folding operations that can guide the deformation. The experimental cases prove the effectiveness of the method of constructing and deforming the Rubik's Snake configurations of the input 3D models. © 2022, The Authors. All rights reserved.

关键词： Deformation

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Observation of intrinsic chiral bound states in the continuum

arXiv

引用

arXiv 2022年

作者： Chen, Yang Deng, Huachun Sha, Xinbo Chen, Weijin Wang, Ruize Chen, Yuhang Wu, Dong Chu, Jiaru Kivshar, Yuri S. Xiao, Shumin Qiu, Cheng-Wei Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore Chinese Academy of Sciences Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision Instrumentation University of Science and Technology of China Hefei230027 China Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Harbin Institute of Technology Shenzhen518055 China Nonlinear Physics Center Research School of Physics Australian National University CanberraACT2601 Australia Pengcheng Laboratory Shenzhen518055 China

Photons with spin angular momentum possess intrinsic chirality which underpins many phenomena including nonlinear optics1, quantum optics2, topological photonics3 and chiroptics4. Intrinsic chirality is weak in natural materials, and recent theoretical proposals5-7 aimed to enlarge circular dichroism by resonant metasurfaces supporting bound states in the continuum that enhance substantially chiral light-matter interaction. Those insightful works resort to three-dimensional sophisticated geometries, which are too challenging to be realized for optical frequencies8. Therefore, most of the experimental attempts9-11 showing strong circular dichroism rely on false/extrinsic chirality by employing either oblique incidence9, 10 or structural anisotropy11. Here, we report on the experimental realization of true/intrinsic chiral response with resonant metasurfaces where the engineered slant geometry breaks both in-plane and out-of-plane symmetries. Our result marks the first observation of intrinsic chiral bound states in the continuum with near-unity chiral dichroism of 0.93 and record-high quality factor exceeding 2663 for visible frequencies. Our chiral metasurfaces promise a plethora of applications in chiral light sources and detectors, chiral sensing, valleytronics and asymmetric photocatalysis. © 2022, CC BY.

关键词： Dichroism

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Study on adjustment of heating scenario factors of rural houses in northeast of China considering air quality and indoor temperature

引用

Energy and Buildings 2025年 344卷

作者： Qing Wu Yunlong Zhu Kailiang Huang Jing Liu School of Municipal and Environment Engineering Shenyang Jianzhu University Shenyang 110168 China School of Architecture and Design Harbin Institute of Technology Harbin 150000 China Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology Ministry of Industry and Information Technology Harbin 150000 China

Due to insufficient technologies and backward economics, indoor environment of rural houses of northeast of China is extremely harsh. It is urgent to find sustainable and low-cost interventions according to local conditions. This paper attempted to clarify the complicated interactions among various heating scenario factors on indoor air pollution concentrations and indoor air temperature, so as to improve the indoor environment level through the adjustment of heating scenario factors. Field measurement on indoor air quality was conducted in rural houses of Shenyang, a typical city in northeast of China. The multiple regression method was used to quantify the roles of multiple scenario factors on indoor pollution levels. The estimation of the regression model’s robustness yielded R 2 of 0.69, 0.68, 0.62, 0.80, for the model of PM2.5, PM10, CO2 and CO, respectively. Indoor air temperature prediction model was proposed based on the equivalent value indoor air temperature and the R 2 was 0.67. The qualitative effects of the combination of scenario factors and outdoor temperature on indoor temperature and pollution level were analyzed. The optimal heating scenario for three typical cities in northeast of China, which were Shenyang, Changchun and Harbin, were analyzed. According to the proposed prediction models and the heating scenario option recommended in this study, indoor environment for rural houses in the northeast of China can be improved to the greatest extent. The attained results in this study are helpful to improve indoor environment of rural houses in northeast of China.

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Copula method of the kinematic accuracy of cylindrical roller bearing

Research Square

引用

Research Square 2021年

作者： Li, Lihong Xue, Yujun Li, Jishun Vehicles & Transportation Engineering Institute Henan University of Science and Technology Luoyang471003 China Henan Key Laboratory for Machinery Design and Transmission System Henan University of Science and Technology Luoyang471003 China State Key Laboratory of Aviation Precision Bearings Luoyang LYC Bearings Co. Ltd. Luoyang471039 China

The kinematic accuracy of cylindrical rollers bearing isn’t only influenced by the dimensional and form precision of its parts, but also more influenced by the cooperation among them. For cylindrical rollers bearing, the main indices of the kinematic accuracy are the ending beat and the radial run out of bearings. There must be dependent relationship between the cooperative action among the parts of bearings and the ending beat or the radial run out of bearings. This relationship is hardly expressed by mathematical formula. However, because the parts dimension deviation and the run out of bearings follow statistic law and have their distribution characteristics, while the copula joint distribution function can connect the run out of bearings with multiple parts dimension accuracy, the copula function is introduced to analyze the dependent relationship between bearing parts cooperative action and its kinematic accuracy. Based on the copula function of statistic theory, the kinematic accuracy of bearings can be forecast by parts geometric accuracy. © 2021, CC BY.

关键词： Kinematics

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Energy balance of mechanically ventilated photovoltaic double skin façade: a case study in summer

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Energy and Built Environment 2025年

作者： Xingjiang Liu Jihong Pu Chao Shen Lin LU Ministry of Industry and Information Technology Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology School of Architecture and Design Harbin Institute of Technology Harbin 150000 China Department of Building Environment and Energy Engineering The Hong Kong Polytechnic University Hong Kong 999077 China

Mechanical ventilation (MV) represents a promising solution to enhance the performance of photovoltaic double skin façade, whereas the trade-off issue between fans-consumed energy ( E fan ) and extra energy benefit remains a critical consideration. This study aims to assess the feasibility of MV during summer and provide insights into its effectiveness. Experimental investigations were conducted to compare the performance under natural and mechanical ventilation. The results indicate that MV enhances airflow and reduces indoor heat gain across the façade area by 18.77%. However, the operation of fans introduces an additional electricity consumption of 10–15 W, partially offsetting the benefits of reduced heat gain. By summarizing the experiment results, an optimization framework of limiting E fan is proposed with four specific approaches, which are believed to reoptimize this trade-off issue and help achieve the feasibility of mechanical ventilation. As one of these four approaches, adjusting the cavity depth has been experimentally verified to improve the energy performance by about 4-7%. This finding partly validates the effectiveness of the proposed optimization framework. In summary, this study highlights the potential of MV in reducing indoor heat gain and suggests avenues for optimizing its energy balance to achieve net energy gain.

关键词： Photovoltaic double skin façade Comparison experiment Mechanical ventilation Building-integrated photovoltaic Solar energy

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Numerical Analysis Of Interface Morphology Effects on Stress Behaviors in Thermal Barrier Coatings with Varied Thicknesses

SSRN

引用

SSRN 2022年

作者： Guo, Wen-Hao Pu, Jian Wu, Wei-Long Wang, Jian-Hua CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Thermal Science and Energy Engineering University of Science and Technology of China No. 96 Jinzhai Road Anhui Hefei230027 China Shenyang Aero-engine Institute of Aero Engine Corporation of China No. 1 Wanlian Road Liaoning Shenyang110015 China

designing thermal barrier coatings (TBCs) with varied thicknesses along the chord of a turbine blade has a practical significance. The present attention was paid to reducing the residual stress levels through optimally designing the interface morphology in TBC at the junction between two zones with different coating-thicknesses. Two-dimensional finite element modeling method was employed to estimate the interface stress level. The combined influences of the internal interface morphology parameters and the external geometrical parameters of TBC on the interface stress behaviors were discussed deeply. The TBC with unchanged thickness was chosen as the reference. The comparisons revealed that the maximum increment in harmful tensile stress level due to the variation of thickness can reach 60%. Relative to the other phases, the interface morphology featuring the zero phase can increase the harmful stress and enlarge the region with high stress level. The non-uniform interface morphology proposed can reduce the harmful stress by about 60%. The criterions of the amplitude-variations and the location of each period with the external geometrical parameters were acquired. The thickened thermal growth oxygen can reduce properly the benefits of the modifications of interface morphology on the stress-reduction;however, the maximum decrement can be controlled below 15%. © 2022, The Authors. All rights reserved.

关键词： Finite element method

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Three-dimensional dirac phonons with inversion symmetry

arXiv

引用

arXiv 2021年

作者： Chen, Z.J. Wang, R. Xia, B.W. Zheng, B.B. Jin, Y.J. Zhao, Yu-Jun Xu, H. Department of Physics South China University of Technology Guangzhou510640 China Department of Physics & Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology China Institute for Structure and Function Department of physics & Center for Quantum Materials and Devices Chongqing University Chongqing400044 China

Dirac semimetals associated with bulk Dirac fermions are well-known in topological electronic systems. In sharp contrast, three-dimensional (3D) Dirac phonons in crystalline solids are still unavailable. Here we perform symmetry arguments and first-principles calculations to systematically investigate 3D Dirac phonons in all space groups with inversion symmetry. The results show that there are two categories of 3D Dirac phonons depending on their protection mechanisms and positions in momentum space. The first category originates from the four-dimensional irreducible representations at the high symmetry points. The second category arises from the phonon branch inversion, and the symmetry guarantees Dirac points to be located along the high symmetry lines. Furthermore, we reveal that non-symmorphic symmetries and the combination of inversion and time-reversal symmetries play essential roles in the emergence of 3D Dirac phonons. Our work not only offers a comprehensive understanding of 3D Dirac phonons but also provides significant guidance for exploring Dirac bosons in both phononic and photonic systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Phonons

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