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Effect of nano-CaO particle on the microstructure,mechanical properties and corrosion behavior of lean Mg-1Zn alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 794-814页

作者： Guangxin Shen Shaoyuan lyu Leiting Yu Tianlu Li Chen You Xuewei Wang Minfang Chen Bin Jiang School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China Key Laboratory of Display Materials and Photoelectric Device(Ministry of Education) Tianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Function Materials Education Tianjin University of TechnologyTianjin 300384China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were *** results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn *** the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of *** Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion *** composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain *** for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.

关键词： Lean Mg alloy In situ MgO Nanoparticles Grain refinement Corrosion resistance

Durable hierarchical phosphorus‐doped biphase MoS_(2)electrocatalysts with enhanced H^(*)adsorption

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Carbon Energy 2024年第4期6卷 104-114页

作者： Yongteng Qian Jianmin Yu Zhiyi lyu Qianwen Zhang Tae Hyeong Lee Huan Pang Dae Joon Kang College of Pharmacy Jinhua PolytechnicJinhuaZhejiangChina Department of Physics Sungkyunkwan UniversitySuwonGyeonggi‐doRepublic of Korea International Collaborative Laboratory of 2D Materials for Optoelectronic Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhenGuangdongChina School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhouJiangsuChina

Phase engineering is an efficient strategy for enhancing the kinetics of electrocatalytic ***,phase engineering was employed to prepare high‐performance phosphorous‐doped biphase(1T/2H)MoS_(2)(P‐BMS)nanoflakes for hydrogen evolution reaction(HER).The doping of MoS_(2)with P atoms modifies its electronic structure and optimizes its electrocatalytic reaction kinetics,which significantly enhances its electrical conductivity and structural stability,which are verified by various characterization tools,including X‐ray photoelectron spectroscopy,high‐resolution transmission electron microscopy,X‐ray absorption near‐edge spectroscopy,and extended X‐ray absorption fine ***,the hierarchically formed flakes of P‐BMS provide numerous catalytic surface‐active sites,which remarkably enhance its HER *** optimized P‐BMS electrocatalysts exhibit low overpotentials(60 and 72 mV at 10 mA cm^(−2))in H_(2)SO_(4)(0.5 M)and KOH(1.0 M),*** mechanism of improving the HER activity of the material was systematically studied using density functional theory calculations and various electrochemical characterization *** study has shown that phase engineering is a promising strategy for enhancing the H*adsorption of metal sulfides.

关键词： 1T/2H MoS_(2) density functional theory electrocatalysts phase engineering phosphorous doping

ResoNet:Robust and Explainable ENSO Forecasts with Hybrid Convolution and Transformer Networks

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Advances in Atmospheric Sciences 2024年第7期41卷 1289-1298页

作者： Pumeng lyu Tao TANG Fenghua LING Jing-Jia LUO Niklas BOERS Wanli OUYANG Lei BAI Shanghai Artificial Intelligence Laboratory Shanghai 200072China Zhejiang Meteorological Observatory Hangzhou 310002China Institute for Climate and Application Research(ICAR) Nanjing University of Information Science and TechnologyNanjing 210044China Technical University of Munich Potsdam Institute for Climate Impact ResearchPotsdam 14473Germany

Recent studies have shown that deep learning(DL)models can skillfully forecast El Niño–Southern Oscillation(ENSO)events more than 1.5 years in ***,concerns regarding the reliability of predictions made by DL methods persist,including potential overfitting issues and lack of ***,we propose ResoNet,a DL model that combines CNN(convolutional neural network)and transformer *** hybrid architecture enables our model to adequately capture local sea surface temperature anomalies as well as long-range inter-basin interactions across *** show that ResoNet can robustly predict ENSO at lead times of 19 months,thus outperforming existing approaches in terms of the forecast *** to an explainability method applied to ResoNet predictions of El Niño and La Niña from 1-to 18-month leads,we find that it predicts the Niño-3.4 index based on multiple physically reasonable mechanisms,such as the recharge oscillator concept,seasonal footprint mechanism,and Indian Ocean capacitor ***,we demonstrate for the first time that the asymmetry between El Niño and La Niña development can be captured by *** results could help to alleviate skepticism about applying DL models for ENSO prediction and encourage more attempts to discover and predict climate phenomena using AI methods.

关键词： deep learning ENSO CNN transformer

Exposure to Chloropropanols and Their Fatty Acid Esters and Glycidyl Fatty Acid Esters in the Sixth Total Diet Study—China,2016-2019

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China CDC weekly 2024年第24期6卷 563-567,I0001页

作者： Dan Huang Xiaomin Xu Bing lyu Jingguang Li Yunfeng Zhao Yongning Wu School of Population Medicine and Public Health Chinese Academy of Medical Sciences Peking Union Medical CollegeBeijingChina NHC Key Lab of Food Safety Risk Assessment Research Unit of Food SafetyChina National Center for Food Safety Risk AssessmentBeijingChina Zhejiang Provincial Center for Disease Control and Prevention Hangzhou CityZhejiang ProvinceChina

What is already known about this topic?Chloropropanols,along with their fatty acid esters and glycidyl fatty acid esters(GEs),are prevalent contaminants in a variety of processed foods,posing potential health risks to *** is added by this report?In the Sixth China Total Diet Study(TDS),3-monochloropropane-1,2-diol esters(3-MCPD esters)and GEs were identified as the predominant chloropropanols and their esters in composite food ***(47.0%)and cereals(15.4%)were the major contributors to exposure among the 12 food categories *** are the implications for public health practice?The Sixth China TDS highlighted concerns regarding potential health risks associated with dietary exposure to *** study underscores the need for further attention in devising practical strategies to mitigate dietary exposure to GEs.

关键词： esters predominant 1,2

The influence of roll angles on unsteady aerodynamics in a canard-configured missile

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International Journal of Mechanical System Dynamics 2024年第2期4卷 213-225页

作者： Kai Wei Shaosong Chen Dongdong Tang Yihang Xu Xujian lyu Qing Chen School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjingChina Shanghai Institute of Spacecraft Equipment ShanghaiChina Jiangnan Design Institute of Mechanical and Electrical GuiyangChina

During the initial stage of vertical launch,a missile may exhibit an uncertain roll angle(φ)and a high angle of attack(α).This study focuses on examining the impact of roll angle variations on the flow field and the unsteady aerodynamics of a canard-configured missile atα=75°.Simulations were performed using the validated k-ωSST turbulence *** analysis encompasses the temporal development of vortices,the oscillatory characteristics of the lateral force,and the fluctuation of kinetic energy distribution within the framework of proper orthogonal decomposition(POD).The results indicate that the flow field surrounding the canardconfigured missile is characterized by inconsistent shedding cycles of Kármán-like and canard-separated vortices.A distinct transition zone is identified between these vortices,where vortex tearing and reconnection phenomena *** increasing roll angles from 0°to 45°,there is an observed shift in the dominant frequency of the lateral force from the higher frequency associated with Kármán-like vortex shedding to the lower frequency of canard vortex *** shedding frequency of Kármán-like vortices corresponds to the harmonics of the canard vortex shedding frequency,indicative of a higher-order harmonic *** frequency of the lateral force is observed to decrease with an increase in roll angle,except in configurations lacking distinct canard-separated vortices,which are characterized by a“+”*** POD analysis reveals that the majority of the fluctuation energy is concentrated in the oscillations and shedding of the canard-separated vortices,leading to pressure fluctuations that are primarily observed on the canard and the downstream region of the canard.

关键词： large angle of attack roll angle unsteady separated flow power spectral density proper orthogonal decomposition

Tunable polarization holographic gratings obtained by varying the ratio of intensities of the recording beams

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Photonics Research 2024年第4期12卷 749-754页

作者： HONG CHEN ZIYAO lyu CHANGSHUN WANG State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100095China

Polarization holography has been extensively applied in many fields, such as optical science, metrology, and biochemistry, due to its property of polarization modulation. However, the modulated polarization state of diffracted light corresponds strictly to that of incident light one by one. Here, a kind of tunable polarization holographic grating has been designed in terms of Jones matrices, and intensity-based polarization manipulation has been realized experimentally. The proposed tunable polarization holographic grating is recorded on an azobenzene liquid-crystalline film by a pair of coherent light beams with orthogonal polarization states and asymmetrically controlled intensities. It is found that the diffracted light can be actively manipulated from linearly to circularly polarized based on the light intensity of the recording holographic field when the polarization state of incident light keeps constant. Our work could enrich the field of light manipulation and holography.

关键词： holographic recording Polarization

Displacement characteristics of CO_(2)flooding in extra-high water-cut reservoirs

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Energy Geoscience 2024年第1期5卷 212-218页

作者： Rui Wang Yaxiong Zhang Chengyuan lyu Zengmin Lun Maolei Cui Dongjiang Lang SINOPEC Petroleum Exploration and Production Research Institute BeijingChina

Carbon dioxide(CO_(2))flooding is a widely applied recovery method during the tertiary recovery of oil and gas.A high water saturation condition in reservoirs could induce a‘water shielding’phenomenon after the injection of CO_(2).This would prevent contact between the injected gas and the residual oil,restricting the development of the miscible zone.A micro-visual experiment of dead-end models,used to observe the effect of a film of water on the miscibility process,indicates that CO_(2)can penetrate the water film and come into contact with the residual oil,although the mixing is significantly ***,the dissolution loss of CO_(2)at high water-cut conditions is not *** oil-water partition coefficient,defined as the ratio of CO_(2)solubility in an oil-brine/two-phase system,keeps constant for specific reservoir conditions and changes little with an injection *** NMR device shows that when CO_(2)flooding follows water flooding,the residual oil decreasesdnot only in medium and large pores but also in small and micro *** levels of higher water saturation,CO_(2)displacement is characterized initially by a low oil production rate and high *** the CO_(2)breakthrough,the water-cut decreases sharply and the oil production rate increases *** response time of CO_(2)flooding at high watercut reservoirs is typically delayed and *** results were confirmed in a pilot test for CO_(2)flooding at the P1-1 well group of the Pucheng *** from this pilot study also suggest that a larger injection gas pore volume available for CO_(2)injection is required to offset the dissolution loss in high water saturation conditions.

关键词： Displacement characteristics CO_(2)flooding Water shield phenomenon Oil-water partition coefficient Response time High water-cut

Time-Domain Analysis of Body Freedom Flutter Based on 6DOF Equation

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工程与科学中的计算机建模(英文) 2024年第1期138卷 489-508页

作者： Zhehan Ji Tongqing Guo Di Zhou Zhiliang Lu Binbin lyu Key Laboratory of Unsteady Aerodynamics and Flow Control Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing210016China High Speed Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang621000China

The reduced weight and improved efficiency of modern aeronautical structures result in a decreasing separation of frequency ranges of rigid and elastic ***,a high-aspect-ratio flexible flying wing is prone to body freedomflutter(BFF),which is a result of coupling of the rigid body short-periodmodewith 1st wing *** prediction of the BFF characteristics is helpful to reflect the attitude changes of the vehicle intuitively and design the active flutter suppression control *** of using the rigid body mode,this work simulates the rigid bodymotion of the model by using the six-degree-of-freedom(6DOF)equation.A dynamicmesh generation strategy particularly suitable for BFF simulation of free flying aircraft is *** accurate Computational Fluid Dynamics/Computational Structural Dynamics/six-degree-of-freedom equation(CFD/CSD/6DOF)-based BFF prediction method is ***,the time-domain CFD/CSD method is used to calculate the static equilibrium state of the *** on this state,the CFD/CSD/6DOF equation is solved in time domain to evaluate the structural response of *** combinedwith the variable stiffnessmethod,the critical flutter point of the model is *** method is applied to the BFF calculation of a flyingwing *** calculation results of the BFF characteristics of the model agree well with those fromthe modalmethod andNastran ***,the method is used to analyze the influence factors of *** analysis results show that the flutter speed can be improved by either releasing plunge constraint or moving the center ofmass forward or increasing the pitch inertia.

关键词： Body freedom flutter time-domain CFD/CSD/6DOF method dynamic mesh generation strategy aeroelasticity

Near-field channel estimation for extremely large-scale Terahertz communications

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Science China(Information Sciences) 2024年第9期67卷 213-228页

作者： Songjie YANG Yizhou PENG Wanting lyu Ya LI Hongjun HE Zhongpei ZHANG Chau YUEN National Key Laboratory of Wireless Communications University of Electronic Science and Technology of China Future Research Laboratory China Mobile Research Institute School of Electrical and Electronics Engineering Nanyang Technological University

Future Terahertz communications exhibit significant potential in accommodating ultra-high-rate services. Employing extremely large-scale array antennas is a key approach to realize this potential, as they can harness substantial beamforming gains to overcome the severe path loss and leverage the electromagnetic advantages in the near field. This paper proposes novel estimation methods designed to enhance efficiency in Terahertz widely-spaced multi-subarray(WSMS) systems. Initially, we introduce three sparse channel representation methods: polar-domain representation(PD-R), multi-angular-domain representation(MADR), and two-dimensional polar-angular-domain representation(2D-PAD-R). Each method is meticulously developed for near-field WSMS channels, capitalizing on their sparsity characteristics. Building on this,we propose four estimation frameworks using the sparse recovery theory: polar-domain estimation(PD-E),multi-angular-domain estimation(MAD-E), two-stage polar-angular-domain estimation(TS-PAD-E), and two-dimensional polar-angular-domain estimation(2D-PAD-E). Particularly, 2D-PAD-E, integrating a 2D dictionary process, and TS-PAD-E, with its sequential approach to angle and distance estimation, stand out as particularly effective for near-field angle-distance estimation, enabling decoupled calculation of these parameters. Overall, these frameworks provide versatile and efficient solutions for WSMS channel estimation,balancing low complexity with high-performance outcomes. Additionally, they represent a fresh perspective on near-field signal processing.

关键词： Terahertz communications near field channel estimation widely-spaced multi-subarray sparse recovery