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Reducing Social Media Attention Inequality in Disasters: The Role of Official Media During Rainstorm Disasters in China

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International Journal of Disaster Risk Science 2024年第3期15卷 388-403页

作者： Longfei Zheng lei chen Fenjie Long Jianing Liu lei Li School of Geography Faculty of Geographical Science Beijing Normal University Hang Lung Center for Real Estate and Department of Construction Management Tsinghua University

Unequal social media attention can lead to potentially uneven distribution of disaster-relief funds, resulting in long-term inequality among regions after disasters. This study aimed to measure inequalities in social media attention to regions during disasters and explore the role of official media in reducing such inequality. This is performed by employing social media,official media, and official aggregated statistics regarding China's rainstorm disasters. Through a set of panel-data regressions and robustness tests, three main conclusions were drawn:(1) There were inequalities among regions regarding social media attention they received during rainstorm disasters. For disasters of the same magnitude, regions with low economic outcome per capita received less attention on social media.(2) Official media can reduce inequality in social media attention during disasters. Official media statements can encourage netizens to pay attention to disaster-stricken areas, and especially the overlooked underdeveloped areas.(3) Of all the measures taken by official media, timely, accurate, and open disclosure of disaster occurrences proved to be the most potent means of leveling the playing field in terms of social media attention;contrarily, promotional or booster-type messages proved futile in this regard. These findings revealed the vulnerabilities within social media landscapes that aff ect disaster relief response, shedding light on the role of official guidance in mitigating inequalities in social media attention during such crises. Our study advises social media stakeholders and policymakers on formulating more equitable crisis communication strategies to bridge the gap in social media attention and foster a more balanced and just relief process.

关键词： China, inequality of attention Official media Rainstorm disasters Situational crisis communication theory Social media

Combined effect of WS_(2) and Ti_(3)C_(2)T_(x) MXene favors oil-based ultra-low friction on rough steel-steel interface at elevated temperatures

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Science China(Technological Sciences) 2024年第7期67卷 1991-2002页

作者： LIU YangQin chen lei WANG Yang QIAN LinMao Tribology Research Institute State Key Laboratory of Rail Transit Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Key Laboratory of Advanced Technologies of Materials(Ministry of Education) Research Institute of Frontier ScienceSouthwest Jiaotong UniversityChengdu 610031China

The lubrication performance of liquids is severely restricted and is degraded in high-temperature environments. Stable and reliable lubrication in high temperature environments has been a long-standing goal in various industrial fields. In this study,WS_(2)and Ti_(3)C_(2)T_(x)MXene nanoflakes were used as oil-based lubricant additives to generate ultra-low friction and even superlubricity(friction coefficient of ~0.007) at elevated temperatures(400℃), which has hitherto not been achieved by both individual pristine materials, WS_(2)and Ti_(3)C_(2)T_(x)MXene. Viscosity and thermogravimetric characterization revealed improvements in the high-temperature rheological properties and thermal stability of the lubricating base oil, indicating improved loadbearing and continuous lubrication capabilities at elevated temperatures. X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy demonstrated that the formation of an iron/titanium/tungsten-rich oxide lubricious thin film at the sliding interface reduced the interfacial shear stress, which was responsible for the observed friction and wear reductions at high contact pressures(> 1.1 GPa). Although the titanium/tungsten oxide film was gradually removed after prolonged sliding, a sufficiently thick iron oxide film maintained a low friction coefficient for at least 2 h. The improved surface quality facilitates the achievement of ultra-low friction and reduced wear. The proposed lubrication methodology has a broad utilization potential as a wear-reduction strategy across various industrial fields at elevated temperatures.

关键词： ultra-low friction high-temperature wear reduction lubricating additive tungsten disulfide MXene

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Effects of vibration conditions,spatial confinement and friction on mixing and segregation characteristics of mixed pebble beds for CFETR WCCB blanket

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Particuology 2024年第2期85卷 268-279页

作者： Yong Liu Chongyang He Cong Wang lei chen Songlin Liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230027China chengdu University Chengdu610106China Zhejiang Lab Hangzhou310000China

This paper presents the study of the dynamic characteristics of confined mixed pebble beds with different friction under different vibration conditions using the discrete element ***λsegre-gation index is used to quantify the degree of particle mixing or *** percolation,convection and diffusion mechanisms are responsible for the segregation patterns of the mixed *** results show the degree of segregation can be suppressed by decreasing the vibration acceleration or free space height below a *** simulation reveals the threshold of vibration acceleration or free space height both are related to the bed height increment which determines the strength of the percolation *** addition,the strength of percolation and convection becomes weaker by decreasing the friction of particles and walls,which makes the pebbled bed remains in a mixed state under *** findings are significant to clarify the main factors behind the three segregation mechanisms and hence provide solutions to retaining the mixed state of the Li2TiO3&Be12Ti mixed pebble bed.

关键词： Vibration Segregation Binary pebble bed Discrete element method

Influence of Film Thickness on Nanofabrication of Graphene Oxide

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Nanomanufacturing and Metrology 2024年第2期7卷 13-25页

作者： Chuan Tang lei chen Linmao Qian Tribology Research Institute The State Key Laboratory of Rail Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and ***,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope *** material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and *** the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step ***,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four ***,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 ***,the GO nanostructures are deoxidized by annealing at 800°C in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman *** work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.

关键词： Graphene oxide Nanofabrication Film thickness step edge Nanopattern Deoxidized treatment

Near-zero-adhesion-enabled intact wafer-scale resist-transfer printing for high-fidelity nanofabrication on arbitrary substrates

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International Journal of Extreme Manufacturing 2024年第1期6卷 313-326页

作者： Zhiwen Shu Bo Feng Peng Liu lei chen Huikang Liang Yiqin chen Jianwu Yu Huigao Duan College of Mechanical and Vehicle Engineering National Engineering Research Centre for High Efficiency GrindingHunan UniversityChangsha 410082People’s Republic of China Greater Bay Area Institute for Innovation Hunan UniversityGuangzhou 511300People’s Republic of China School of Mechanical Engineering Hunan University of Science and TechnologyXiangtan 411201People’s Republic of China Shenzhen Research Institute Hunan UniversityShenzhen 518000People’s Republic of China

There is an urgent need for novel processes that can integrate different functional nanostructures onto specific substrates,so as to meet the fast-growing need for broad applications in nanoelectronics,nanophotonics,and fexible *** direct-lithography methods are difficult to use on fexible,nonplanar,and biocompatible ***,this fabrication is usually accomplished by nanotransfer ***,large-scale integration of multiscale nanostructures with unconventional substrates remains challenging because fabrication yields and quality are often limited by the resolution,uniformity,adhesivity,and integrity of the nanostructures formed by direct ***,we proposed a resist-based transfer strategy enabled by near-zero adhesion,which was achieved by molecular modification to attain a critical surface energy *** approach enabled the intact transfer of wafer-scale,ultrathin-resist nanofilms onto arbitrary substrates with mitigated cracking and wrinkling,thereby facilitating the in situ fabrication of nanostructures for functional *** this approach,fabrication of three-dimensional-stacked multilayer structures with enhanced functionalities,nanoplasmonic structures with~10 nm resolution,and MoS2-based devices with excellent performance was demonstrated on specific *** results collectively demonstrated the high stability,reliability,and throughput of our strategy for optical and electronic device applications.

关键词： resist-based transfer printing near-zero adhesion critical surface energy wafer-scale nanofabrication in situ fabrication optoelectronic devices

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Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane oxidation with molecular oxygen and the active sites investigation

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 101-112页

作者： lei chen Yuan Sun Jinshan Chi Wei Xiong Pingle Liu Fang Hao College of Chemical Engineering National&Local United Engineering Research Centre for Chemical Process Simulation and IntensificationXiangtan UniversityXiangtan411105China

The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol(KA oil)is a challenging issue in the chemical *** present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5%***,the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency ***,we have developed a cobalt-nitrogen co-doped porous sphere catalyst,Co-NC-x(x is the Zn/Co molar ratio,where x=0,0.5,1,2,and 4)by pyrolyzing resorcinol-formaldehyde resin *** achieved 88.28%cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88%under *** results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the *** addition,Co0 and pyridinic-N are proposed to be the possible active species,and their proportion efficiently increased in the presence of Zn^(2+)*** this study,we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词： KA oil production cyclohexane selective oxidation cobalt-nitrogen co-doped porous carbon spheres metal-organic framework

Hollow Metal-Organic Framework/MXene/Nanocellulose Composite Films for Giga/Terahertz Electromagnetic Shielding and Photothermal Conversion

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Nano-Micro Letters 2024年第9期16卷 161-179页

作者： Tian Mai lei chen Pei‑Lin Wang Qi Liu Ming‑Guo Ma Research Center of Biomass Clean Utilization MOE Engineering Research Center of Forestry Biomass Materials and BioenergyBeijing Key Laboratory of Lignocellulosic ChemistryCollege of Materials Science and TechnologyBeijing Forestry UniversityBeijing 100083People’s Republic of China State Silica-Based Materials Laboratory of Anhui Province Bengbu 233000People’s Republic of China

With the continuous advancement of communication technology,the escalating demand for electromagnetic shielding interference(EMI)materials with multifunctional and wideband EMI performance has become *** the electrical and magnetic components and designing the EMI material structure have attracted extensive interest,but remain a huge ***,we reported the alternating electromagnetic structure composite films composed of hollow metal-organic frameworks/layered MXene/nanocellulose(HMN)by alternating vacuum-assisted filtration *** HMN composite films exhibit excellent EMI shielding effectiveness performance in the GHz frequency(66.8 dB at Kaband)and THz frequency(114.6 dB at 0.1-4.0 THz).Besides,the HMN composite films also exhibit a high reflection loss of 39.7 dB at 0.7 THz with an effective absorption bandwidth up to 2.1 ***,HMN composite films show remarkable photothermal conversion performance,which can reach 104.6℃under 2.0 Sun and 235.4℃under 0.8 W cm^(−2),*** unique micro-and macrostructural design structures will absorb more incident electromagnetic waves via interfacial polarization/multiple scattering and produce more heat energy via the local surface plasmon resonance *** features make the HMN composite film a promising candidate for advanced EMI devices for future 6G communication and the protection of electronic equipment in cold environments.

关键词： Metal-organic frameworks MXene Nanocellulose Electromagnetic shielding Photothermal conversion

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Highly sensitive nanozyme strip:An effective tool for forensic material evidence identification

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Nano Research 2024年第3期17卷 1785-1791页

作者： Juanji Hong Zhanjun Guo Dihan Duan Yi Zhang Xin chen Yongjiu Li Zheng Tu lei Feng lei chen Xiyun Yan Lizeng Gao Minmin Liang Demin Duan Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China College of Bioscience and Biotechnology Shenyang Agricultural UniversityShenyang 110866China Chongqing kangjuquanhong biology science and technology Co. ltdChongqing 400026China Key Laboratory of Forensic Genetics Institute of Forensic ScienceMinistry of Public SecurityBeijing 100038China CAS Engineering Laboratory for Nanozyme Key Laboratory of BiomacromoleculesInstitute of BiophysicsChinese Academic of ScienceBeijing 100101China

During criminal case investigations,blood evidence tracing is critical for criminal ***,the blood stains are often cleaned or covered up after the crime,resulting in trace residue and difficult ***,a highly sensitive and specific method for the rapid detection of human blood stains remains *** solve this problem,we established a nanozyme-based strip for rapid detection of blood evidence with high sensitivity and *** construct reliable nanozyme strips,we synthesized CoFe_(2)O_(4) nanozymes with high peroxidase-like activity by scaling up to gram level,which can be supplied for six million tests,and conjugated antibody as a detection probe in nanozyme *** developed CoFe_(2)O_(4) nanozyme strip can detect human hemoglobin(HGB)at a concentration as low as 1 ng/mL,which is 100 times lower than the commercially available colloidal gold strips(100 ng/mL).Moreover,this CoFe_(2)O_(4) nanozyme strip showed high generality on 12 substrates and high specificity to human HGB among 13 animal blood ***,we applied the developed CoFe_(2)O_(4) nanozyme strip to successfully detect blood stains in three real cases,where the current commercial colloidal gold strip failed to *** results suggest that the CoFe_(2)O_(4) nanozyme strip can be used as an effective on-scene detection method for human blood stains,and can further be used as a long-term preserved material evidence for traceability inquiry.

关键词： CoFe_(2)O_(4)nanozyme nanozyme strip peroxidase-like activity human hemoglobin blood evidence

Sustainable development of electroencephalography materials and technology

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SusMat 2024年第2期4卷 125-144页

作者： Ling Xiong Nannan Li Yi Luo lei chen Institutes for Breast Health Medicine West China HospitalSichuan UniversityChengduChina Micro/Nano Fabrication Laboratory Microsystem and Terahertz Research CenterChina Academy of Engineering PhysicsChengduChina Institute of Electronic Engineering China Academy of Engineering PhysicsMianyangChina Department of Neurology Joint Research Institution of Altitude HealthWest China HospitalSichuan UniversityChengduChina

Electroencephalogram(EEG)is one of the most important bioelectrical signals related to brain activity and plays a crucial role in clinical *** by continuously expanding applications,the development of EEG materials and technology has attracted considerable ***,systematic analysis of the sustainable development of EEG materials and technology is still *** review discusses the sustainable development of EEG materials and ***,the developing course of EEG is introduced to reveal its significance,particularly in clinical ***,the sustainability of the EEG materials and technology is discussed from two main aspects:integrated systems and EEG *** integrated systems,sustainability has been focused on the developing trend toward mobile EEG systems and big-data monitoring/analyzing of EEG *** is related to miniaturized,wireless,portable,and wearable systems that are integrated with big-data modeling *** EEG electrodes and materials,sustainability has been comprehensively analyzed from three perspectives:performance of different material/structural categories,sustainablematerials for EEGelectrodes,and sustainable manufacturing *** addition,sustainable applications of EEG have been ***,the sustainable development of EEG materials and technology in recent decades is summarized,revealing future possible research directions as well as urgent challenges.

关键词： clinical medicine electroencephalography technology limitations and future directions materials and electrodes sustainable development