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Applied Mathematics and Mechanics(English Edition) 2023年第9期44卷 1457-1486页

作者： Qiao zhang yuxin SUN National Key Laboratory of Strength and Structural Integrity School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China

This paper proposes a three-dimensional(3D)Maltese cross metamaterial with negative Poisson’s ratio(NPR)and negative thermal expansion(NTE)adopted as the core layers in sandwich plates,and aims to explore the relations between the mechanical responses of sandwich composites and the NPR or NTE of the metamaterial.First,the NPR and NTE of the metamaterial are derived analytically based on energy conservation.The effective elastic modulus and mass density of the 3D metamaterial are obtained and validated by the finite element method(FEM).Subsequently,the general governing equation of the 3D sandwich plate under thermal environments is established based on Hamilton’s principle with the consideration of the von Kármán nonlinearity.The differential quadrature(DQ)FEM(DQFEM)is utilized to obtain the numerical solutions.It is shown that NPR and NTE can enhance the global stiffness of sandwich structures.The geometric parameters of the Maltese cross metamaterial significantly affect the responses of the thermal stress,natural frequency,and critical buckling load.

关键词： negative Poisson's ratio(NPR) negative thermal expansion(NTE) sand-wich plate vibration buckling

Raindrop Size Distribution Measurements at High Altitudes in the Northeastern Tibetan Plateau during Summer

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Advances in Atmospheric Sciences 2023年第7期40卷 1244-1256页

作者： Huibang HAN yuxin Zhang Jianbing TIAN Xiaoyan KANG Meteorological Disaster Prevention Technology Center in Qinghai Province Xining 810000China Key Laboratory for Disaster Prevention and Mitigation in Qinghai Province Xining 810000China

Characteristics of raindrop size distribution during summer are studied by using the data from six Parsivel disdrometers located in the northeastern Tibetan Plateau.The analysis focuses on convective and stratiform precipitation at high altitudes from 2434 m to 4202 m.The results show that the contribution of stratiform and convective precipitation with rain rate between 1≤R<5 mm h^(-1) to the total precipitation increases with altitude,and the raindrop scale and number concentration of convective precipitation is larger than that for stratiform precipitation.The droplet size spectra of both stratiform and convective precipitation shows a single peak with a peak particle size between 0.31–0.50 mm,and they have essentially the same peak particle size and number concentration at the same altitude.The maximum spectral widths of stratiform clouds are between 4 mm and 5 mm,while those of convective clouds range from 4 mm to 8 mm.The Gamma distribution is more suitable than the Marshall-Palmer distribution in terms of the actual raindrop spectrum distribution.The stratiform precipitation particles are smaller with higher number concentration,while the opposite is true for the convective precipitation particles.The convective precipitation particles drop faster than stratiform precipitation particles when the particle size exceeds 2 mm,and the falling velocity of raindrops after standard curve fitting is underestimated during the observation period.Moreover,conventional radar estimation methods would underestimate the precipitation in the Northeastern Tibetan Plateau.

关键词： raindrop size distribution precipitation microphysics Northeastern Tibetan Plateau fall velocity

Heat wave mitigation of ecosystems in mountain areas-a case study of the Upper Yangtze River basin

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Ecosystem Health and Sustainability 2022年第1期8卷 370-382页

作者： yuxin Zhang Bin Fu Juying Sun Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengduChina State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengduChina Ecological Value Evaluation Centre China Quality Certification CentreBeijingChina

Background:Natural ecosystems,such as forests and grasslands,can mitigate heat waves,but research on heat wave mitigation in mountain ecosystems is lacking.Considering the upper reaches of the Yangtze River basin(URYB)as the study area,we first divided the URYB into mountainous and non-mountainous areas based on a digital elevation model(DEM).Then,we used temperature to identify heat waves and used the temperature and humidity index to identify suitable days.Finally,the differences between mountainous and non-mountainous areas were compared,and regional development strategies are proposed.Result:(1)The frequency and duration of heat waves increased by 0.433/y(P<0.1),0.07/y(P<0.05),while the number of suitable days in June,July,and August gradually decreased slightly by 0.0096/y(P<0.1),0.0125/y(P<0.1),0.004/y(P<0.1),respectively from 1986 to 2015.(2)The average monthly number of suitable days was the highest in mountainous areas during the summer from 1986 to 2015.Mountainous areas have an advantage in mitigating heat waves owing to landform-based changes in the local climate.(3)In addition to the landform,altitude was the main factor responsible for mitigating heat waves in mountainous areas.Conclusion:Parts of the plateau and whole mountain areas were found to be best for avoiding extremely high temperatures based on the number of suitable summer days from 1986 to 2015.We suggest formulating tourism promotion strategies,and strengthening tourism infrastructure,considering landscape protection and creation to promote sustainable regional development.

关键词： Ecosystem services thermal comfort livability summer temperature mountains tourism

High-flow nasal cannula oxygen therapy is superior to conventional oxygen therapy but not to non-invasive mechanical ventilation in reducing intubation rate in hypoxia and dyspnea due to acute heart failure: a systematic review and meta-analysis

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Chinese Medical Journal 2023年第4期136卷 479-481页

作者： Shuai Yang Yan He Shengming Liu yuxin Zhang Department of Emergency Intensive Care Unit Zhuhai People’s Hospital(Zhuhai Hospital Affiliated with Jinan University)ZhuhaiGuangdong 519000China Department of Respiratory and Critical Care Medicine The First Affiliated Hospital of Jinan UniversityGuangzhouGuangdong 510630China Department of Gastroenterology Zhuhai People’s Hospital(Zhuhai Hospital Affiliated with Jinan University)ZhuhaiGuangdong 519000China

To the Editor:Acute heart failure(AHF)is a leading cause of hospitalization.Most patients with AHF present with hypoxia and dyspnea.Treatment of these patients often requires oxygenation via facemask and more intensive respiratory support methods,including non-invasive ventilation(NIV)or invasive ventilation through endotracheal intubation.

关键词： invasive Acute intubation

A route for large-scale preparation of multifunctional superhydrophobic coating with electrochemically-modified kaolin for efficient corrosion protection of magnesium alloys

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Journal of Magnesium and Alloys 2022年第11期10卷 3082-3099页

作者： Xiang Liu Tian C.zhang yuxin Zhang Jinsong Rao Shaojun Yuan Low-carbon Technology&Chemical Reaction Engineering Lab College of Chemical EngineeringSichuan UniversityChengdu 610065China Civil&Environmental Engineering Department University of Nebraska-LincolnOmahaNE 68182-0178USA State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing 400044China

Superhydrophobic coating has been widely studied for its great applicational potential, such as for corrosion protection of magnesium alloys while it has been restrained by expensive materials, sophisticated preparation process and infirm rough structures. In this study, the electrochemical method was adopted by using a two-electrode system for rapid hydrophobic modification to obtain superhydrophobic kaolin.By mixing the modified superhydrophobic kaolin with commercial epoxy resin and polydimethylsiloxane glue, a paint can be formed and easily used on various substrates for preparation of superhydrophobic coating via spraying method. The influence factors on wettability of the modified kaolin and the mixing ratio of each component of the coating were explored. Also, the wettability, durability and anticorrosion of the prepared coating were evaluated comprehensively. The coating was able to maintain superhydrophobic after immersed in HCl solution at pH 1, the NaOH solution at pH 14, and 3.5 wt.% NaCl solution for 16, 21, 30 days, respectively. In addition, the coating exhibited 4A grade adhesion, high hydrophobicity after abraded for 200 cycles on a 600-mesh sandpaper with 100 g weight, and 99.86% anticorrosion efficiency after soaked in 3.5 wt.% NaCl solution for 20 days, demonstrating a good robustness and anti-corrosion property. Furthermore, the coating showed good transparency, flexibility and was easy to make in a large scale by the spraying method, which is of great significance to promote the practical application of superhydrophobic coatings and the anticorrosion Mg alloys.

关键词： Superhydrophobic coating Large-scale application Magnesium alloys Corrosion protection

Chemical Modifications of Layered Double Hydroxides in the Supercapacitor

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Energy & Environmental Materials 2020年第3期3卷 346-379页

作者： Chuan Jing Biqin Dong yuxin Zhang State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen 518060China

Layered double hydroxides are one class or kind of 2 D layered materials that are considered promising for use in the supercapacitor.Although there have been many studies on the structure,composition,properties,and electrode fabrication of layered double hydroxides,none summarize the effects of various modification methods on the structure and performance of layered double hydroxides in the supercapacitor.In a bid to fill this gap,in this review,we summarize the progress of modification methods such as exfoliation,intercalation,vacancy,doping,phase transformation,and composition regulation of layered double hydroxides in the field of the supercapacitor and put forward some opinions regarding the progress of research on the methods used in modifying the layered double hydroxides.

关键词： 2D materials chemical modifications layered double hydroxide supercapacitor

International public opinion analysis of four olympic games:From 2008 to 2022

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Journal of Safety Science and Resilience 2022年第3期3卷 252-262页

作者： Kun Jia Yizhen Zhu yuxin Zhang Feng Liu Jiayin Qi Institute of Artificial Intelligence and Change Management Shanghai University of International Business and EconomicsShanghai 201620China School of Statistics and Information Shanghai University of International Business and EconomicsShanghai 201620China School of Computer Science and Technology East China Normal UniversityShanghai 200062China Shanghai Key Laboratory of Mental Health and Psychological Crisis Intervention other institutesSchool of Psychology and Cognitive ScienceEast China Normal UniversityShanghai 200062China

Since the rapid spread of the COVID-19 worldwide,the pandemic has led to a huge impact on global sporting events.As a major international event,the 2022 Beijing Winter Olympics has commonalities with the 2008 Beijing Olympics,the 2014 Sochi Winter Olympics,and the 2020 Tokyo Olympics in terms of international public opinion context and epidemiological background.In this study,over 1 million pieces of UGC(User Generated Contents)in Chinese and English languages were obtained from social media platforms such as Twitter,YouTube,as well as traditional mass media in various countries to compare the differences between the two languages in international public opinion.Using sentiment analysis,this study explores the evolution of international public opinion topics and sentiment differences among the above four Olympic Games.The analysis results show that:1)regardless of traditional mass media or online social media,there is a more obvious tendency of general politicization in the topics of the 2008 Beijing Olympics and 2022 Beijing Winter Olympics,and extreme emotional remarks of the 2022 Beijing Winter Olympics are more frequent;2)in the topic of political opinion involving China,international Chinese public opinion presents more negative sentiment than those in English;3)Among the topics involving COVID-19,the negative level of public opinion in Chinese and English is opposite for the 2020 Tokyo Olympics and the 2022 Beijing Winter Olympics;4)International public opinion on the topic of sports events is significantly more positive in Chinese than in English;5)YouTube’s Chinese opinion environment is better than English.

关键词： Public opinion Sentiment analysis Olympic games COVID-19 pandemic Computational affection

Photoelectrocatalytic carbon dioxide reduction: Fundamental, advances and challenges

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Nano Materials Science 2021年第4期3卷 344-367页

作者： Peng Chen yuxin Zhang Ying Zhou Fan Dong School of New Energy and Materials Southwest Petroleum UniversityChengdu610500China Research Center for Environmental and Energy Catalysis Institute of Fundamental and Frontier SciencesUniversity of Electronic Science and Tehnology of ChinaChengdu611731China College of Materials Science and Engineering Chongqing University Chongqing400044China

With the rising global population,increasing energy demand and rapid climate change,great concems have been raised for environment and energy security in future.Solar-driven CO_(2) reduction provides a promising way to deal with energy crists and global warming,which has been widely concemed.Photoelectrocatalysis technology can effectively utilize solar energy and avoid to use high-temperature and high-voltage reduction environment by integrating the vantages of both photocatalysis and electrocatalysis,which exhibits a broad application prospect of CO_(2) reduction with a high efficiency and ecellent selectivity.In this review,basic pr inciples of CO_(2) reduction by photocatalysis,electrocatalysis and photoeletrocatalysis are briely reviewed,also comparing the technical character istics of the above technologies.Diferent photoelectrocatalyde systems for CO_(2) reduction are described and compared.The several key influencing factors of photoeletrocatalytic performance of CO_(2) reduction are discussed,including inter action between reaction molecules and catalysts,reaction conditions and influence of photoelectrode.Then,the advances on reaction mechanisms and strategies of perfor mance enhancement by opd:mizing photoexcitation,charge separation efficiency and surface reaction were reviewed.Besides,the chal-lenges and prospects of photoelectrocatalyde CO_(2) reduction will be also discussed.

关键词： Photoeletrocatalytic CO_(2)reduction Basic principles Influencing factors Reaction mechanisms

Corrosion inhibition of layered double hydroxides for metal-based systems

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Nano Materials Science 2021年第1期3卷 47-67页

作者： Chuan Jing Biqin Dong Aikifa Raza Tiejun zhang yuxin Zhang State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing400044PR China Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering Shenzhen UniversityShenzhen518060PR China Department of Mechanical Engineering Masdar InstituteKhalifa University of Science and TechnologyP.O.Box 127788Abu DhabiUnited Arab Emirates

Layered double hydroxide(LDH),a kind of 2D layered materials,has been recognized as the promising anticorrosion materials for metal and its alloy.The microstructure,physical/chemical properties,usage in corrosion inhibition and inhibition performance of LDH have been studied separately in open literature.However,there is a lack of a complete review to summarize the status of LDH technology and the potential R&D opportunities in the field of corrosion inhibition.In addition,the challenges for LDH in corrosion inhibition of metal-based system have not been summarized systematically.Herein,we review recent advances in the rational design of LDH for corrosion inhibition of metal-based system(i.e.Mg alloy,Al alloy,steel and concrete)and high-throughput anticorrosion materials development.By evaluating the physical/chemical properties,usage in metal-based system and the corrosion inhibition mechanism of LDH,we highlight several important factors of LDH for anticorrosion performance and common features of LDH in applying different metal alloys.Finally,we provide our perspective and recommendation in this field,including high-throughput techiniques for combinatorial compositional design and rapid synthesis of anticorrosion alloys,with the goal of accelerating the development and application of LDH in corrosion inhibition of metal-based system.

关键词： Layered double hydroxide Corrosion inhibition Magnesium alloy Aluminum alloy Steel Concrete

MnO2-directed synthesis of NiFe-LDH@FeOOH nanosheeet arrays for supercapacitor negative electrode

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Chinese Chemical Letters 2020年第9期31卷 2343-2346页

作者： Qing Sun Kexin Yao yuxin Zhang Multi-scale Porous Materials Center Institute of Advanced Interdisciplinary StudiesCollege of Chemistry and Chemical EngineeringChongqing UniversityChongqing 400044China State Key Laboratory of Mechanical Transmission College of Materials Science and EngineeringChongqing UniversityChongqing 400044China

The complex-architectured NiFe-LDH@FeOOH negative material was first prepared by simple two-step hydrothermal method.In this study,the porous nanostructure of FeOOH nanosheets features a large number of accessible channels to electroactive sites and the two-dimensional layered structure of NiFe-LDH nanosheets have an open spatial structure with high specific surface area,which enhance the diffusion of ions in the active material.Benefited from above advantages,the excellent electrochemical properties were demonstrated.NiFe-LDH@FeOOH nanocomposites present high specific capacitance(1195 F/g at a current density of 1 A/g),lower resistance and well cycling performance(90.36% retention after 1000 cycles).Furthermore,the NiFe-LDH@MnO2//NiFe-LDH@FeOOH supercapacitor exhibits22.68 Wh/kg energy density at 750 W/kg power density,demonstrating potential application in energy storage devices.

关键词： NiFeLDH FeOOH Supercapacitor Negative electrode Electrochemical performance