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Deep-subwavelength single grooves prepared by femtosecond laser direct writing on Si

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Chinese Physics B 2024年第8期33卷 108-115页

作者：叶瑞熙黄敏 State Key Laboratory of Optoelectronic Materials and Technologies School of PhysicsSun Yat-sen UniversityGuangzhou 510275China

It is well known that femtosecond laser pulses can easily spontaneously induce deep-subwavelength periodic surface structures on transparent dielectrics but not on non-transparent ***,in this study,we demonstrate that using high-numerical-aperture 800 nm femtosecond laser direct writing with controlled pulse energy and scanning speed in the near-damage-threshold regime,polarization-dependent deep-subwavelength single grooves with linewidths of~180 nm can be controllably prepared on ***,the single-groove linewidth increases slightly with increase in the pulse energy and decrease in the scanning speed,whereas the single-groove depth significantly increases from~300 nm to~600 nm with decrease in the scanning speed,or even to over 1μm with multi-processing,indicating the characteristics of transverse clamping and longitudinal growth of such deep-subwavelength single *** dispersive spectroscopy composition analysis of the near-groove region confirms that single-groove formation tends to be an ultrafast,non-thermal ablation process,and the oxidized deposits near the grooves are easy to clean ***,the results,showing both the strong dependence of groove orientation on laser polarization and the occurrence of double-groove structures due to the interference of pre-formed orthogonal grooves,indicate that the extraordinary field enhancement of strong polarization sensitivity in the deep-subwavelength groove plays an important role in single-groove growth with high stability and collimation.

关键词： femtosecond-laser direct writing of Si deep-subwavelength single grooves polarization dependence high numerical aperture ultrafast non-thermal ablation

Degradation of neonicotinoids with different molecular structures in heterogeneous peroxymonosulfate activation system through different oxidation pathways

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Chinese Chemical Letters 2024年第9期35卷 331-339页

作者： Ruonan Guo Heng Zhang Changsheng Guo Ningqing Lv Beidou xi Jian Xu State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China school of Environment Tsinghua UniversityBeijing 100084China

The elimination of neonicotinoids(NEOs)from water has been a research priority due to their threats to human health and *** this study,we established the heterogeneous peroxymonosulfate(PMS)activation system using manganese catalyst(Mn NC)and cobalt catalyst(Co NC)to trigger the nonradical oxidation and synergistic oxidation pathway,respectively to remove *** results showed that the nonradical oxidation system exhibited superior NEOs degradation *** composition of organic pollutants in wastewater significantly impacted subsequent degradation *** charge distribution and reaction sites of various NEOs were analyzed using density functional theory(DFT)calculations,and it demonstrated the electron distribution and activity of NEOs were significantly influenced by the type and number of *** group(–NO_(2.)and cyanide group(–C≡N)were identified as strong electron-withdrawing groups and prone to be attacked by negatively charged *** transformation of NEOs was analyzed,and result showed that the C and N sites adjacent to the nitro group and cyanide group were more susceptible to oxidation attacks.S and N atoms,which possess strong electronegativity and high electron cloud density,were identified as key active sites in the degradation *** outcomes of this study provide valuable guidance for the oriented regulation of oxidation pathways towards efficient removal of NEOs in water.

关键词： Fenton-like processes Molecular structure Neonicotinoids Nonradical oxidation Degradation pathway

Responses of arbuscular mycorrhizal fungi to straw return and nitrogen fertilizer reduction in a rainfed maize field

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Pedosphere 2024年第2期34卷 351-360页

作者： Zhenling PENG Hao xi Lin MAO Huyuan FENG Jianjun ZHANG Yongjun LIU State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China College of Life sciences Northwest Normal UniversityLanzhou 730070China school of Life sciences Lanzhou UniversityLanzhou 730000China Dryland Agriculture Institute Gansu Academy of Agricultural SciencesLanzhou 730070China

Straw return can be used to reduce fertilizer input and improve agricultural sustainability and soil ***,how straw return and reduced fertilizer application affect beneficial soil microbes,particularly arbuscular mycorrhizal fungi(AMF),remains poorly ***,we conducted a five-year field experiment in a rainfed maize field on the Loess Plateau of northwestern *** tested four treatments with straw return combined with four nitrogen(N)application rates,i.e.,100%,80%,60%,and 0%of the common N application rate(2.5 kg N ha^(-1)year^(-1))in this region,and two reference treatments(full or no N application),with three replicates for each *** colonization was quantified and AMF communities colonizing maize roots were characterized using Illumina *** virtual taxa(VTs)of AMF were identified in root samples,among which VT113(related to Rhizophagus fasciculatus)and VT156(related to Dominikia gansuensis)were the predominant *** root length colonization and AMF VT richness were sensitive to N fertilization,but not to straw return;furthermore,both gradually increased with decreasing N application *** VT composition of the AMF community was also affected by N fertilization,but not by straw return,and the community variation could be well explained by soil available N and phosphorus ***,60%,80%,and full N fertilization produced similar maize ***,our study revealed the response patterns of AMF to straw return and N fertilizer reduction and showed that straw return combined with N fertilizer reduction may be a promising practice to maintain mycorrhizal symbiosis concomitantly with crop productivity.

关键词： agricultural sustainability crop productivity mycorrhizal colonization mycorrhizal symbiosis root length colonization virtual taxon

Numerical study on the filtration characteristics of fine particles in granular bed filter at high temperature

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Particuology 2024年第10期93卷 41-53页

作者： Kangning Zhu Jie Cai Yuan Li xiaoyou Shen Jianfei xi Yunjun Wang Zhongzhu Gu school of Energy and Mechanical Engineering Nanjing Normal UniversityNanjing210023China

Granular bed filter(GBF)has become one of the current research hot topics due to its excellent performance in removing fine *** this paper,a three-dimensional fixed bed GBF filtration model was established and its accuracy was ***,the GBF filtration performance at high temperature were *** results demonstrate that elevating the temperature diminishes the filtration efficiency,albeit to a limited *** increasing of inlet gas velocity can significantly improve pressure drop for GBF and the filtration efficiency for fine particles of sizes larger than 5μ*** the diameter of stacked granular particle diameter grows,the filtration efficiency and pressure drop *** density of fine particles almost does not affect the filtration efficiency for fine particles of 1∼7μm,but a higher density leads to a higher filtration efficiency for fine particles of sizes bigger than 9μ***,as the fine particles size increases,the change of the filtration efficiency roughly goes through three stages:Stage 1:the filtration efficiency is basically unchanged;Stage 2.the filtration efficiency increases rapidly;Stage 3:the filtration efficiency increases steadily,but the rate of increase slows *** the increase of the fine particles Stokes number,the filtration efficiency of GBF will pass through two phases of stabilization and rapid increase.

关键词： Granular bed filter Fine particles High temperature Filtration efficiency

Metal-organic cage as fluorescent probe for LiPF_(6)in lithium batteries

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Green Energy & Environment 2024年第10期9卷 1592-1600页

作者： xi Li Dehua Xu Aoxuan Wang Chengxin Peng xingjiang Liu Jiayan Luo Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China school of Materials science and Engineering University of Shanghai Science and TechnologyShanghai200093China State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China

Lithium hexafluorophosphate(LiPF_(6)),the most commonly used lithium battery electrolyte salt,is vulnerable to heat and *** and qualitative determination the variation of LiPF_(6)have always relied on advanced ***,we develop a fast,convenient,high-selective fluorescence detection method based on metal-organic cages(MOC),whose emission is enhanced by nearly 2. times in the presence of LiPF_(6)with good stability and photobleaching *** fluorescent probe can also detect moisture in battery *** propose and verify that the luminescence enhancement is due to the presence of hydrogen bond-induced enhanced emission effect in *** excitation-emission matrix spectra and variable-temperature nuclear magnetic resonance spectroscopy are employed to clarify the role of hydrogen bonds in guest-loaded *** functional theory(DFT)calculation is applied to simulate the structure of host-guest complexes and estimate the adsorption energy involved in the *** precisely matched lock-and-key model paves a new way for designing and fabricating novel host structures,enabling specific recognition of other target compounds.

关键词： Metal-organic cage Selective fluorescence probe Moisture detection Hydrogen bond Host-guest complex

A method for support stiffness failure identification in a steel spring floating slab track of urban railway: a case study in china

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Journal of Zhejiang university-science A(Applied Physics & Engineering) 2024年第3期25卷 206-222页

作者： Junyuan ZHENG Caiyou ZHAO Duojia SHI Ping WANG Jian WANG Bolong JIANG xi SHENG Key Laboratoryof High-speed Railway Engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China school of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China 01 DYNA(Qingdao)Test&Data Co. Ltd.Qingdao 266000China Rail Transit Digital Construction and Measurement Technology National Engineering Research Center China Railway Design CorporationTianjin300308China Institute of Urban Smart Transportation&Safety Maintenance Shenzhen UniversityShenzhen 518060China

The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit ***,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often *** failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection *** the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving *** study first establishes a detailed coupled train-floating slab track-foundation analytical *** the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is ***,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern *** a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was *** investigation results were consistent with the damage identification *** repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been *** proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.

关键词： Floating slab track Support stiffness Detailed analytical model Failure identification Monitoring system

Reaction behavior of MgO refractory with high-Mn and high-Al steel

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Journal of Iron and Steel Research International 2024年第6期31卷 1389-1398页

作者： Ling-zhong Kong Lin Zu Jie Yang xi-min Zang xin Yang Ming Kang school of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

To understand the mechanism of the interfacial reaction between high-Mn and high-Al steel and MgO refractory,a series of laboratory experiments as well as thermodynamic calculations were *** effects of Mn and Al contents in the steel and the reaction time on the interfacial reaction were *** was observed that the erosion of the MgO refractory is caused by the reaction of Al and Mn in the steel with MgO in the refractory,which would lead to the formation of(Mn,Mg)O·Al_(2.O_(3) spinel and(Mn,Mg)O solid *** formation mechanism of the spinel and solid solution is as *** Al in the steel firstly reacts with MgO in the refractory to generate MgO·Al_(2.O_(3) spinel,and then,the spinel reacts with Mn in the steel to form(Mn,Mg)O·Al_(2.O_(3) ***,the MnO in the spinel reacts with the MgO in the inner refractory to form(Mn,Mg)O solid *** addition,only(Mn,Mg)O·Al_(2.O_(3) spinel is present in the interfacial reaction layer of the refractory when the Al content in the steel is sufficient.

关键词： High-Mn high-Al steel MgO refractory Reaction behavior Spinel

Gamma Approximation Based Multi-Antenna Covert Communication Detection

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china Communications 2024年第9期21卷 90-97页

作者： Wan Pengwu Chen Dongrui Wang Danyang Hui xi Peng Kang school of Communications and Information Engineering&school of Artificial Intelligence Xi’an University of Posts and TelecommunicationsXi’an 710121China Key Laboratory of Integrated Service Networks School of Telecommunications EngineeringXidian UniversityXi’an 710071China

Covert communication technology makes wireless communication more secure,but it also provides more opportunities for illegal users to transmit harmful *** order to detect the illegal covert communication of the lawbreakers in real time for subsequent processing,this paper proposes a Gamma approximation-based detection method for multi-antenna covert communication ***,the Gamma approximation property is used to calculate the miss detection rate and false alarm rate of the monitor *** the optimization problem to minimize the sum of the missed detection rate and the false alarm rate is *** optimal detection threshold and the minimum error detection probability are solved according to the properties of the Lambert W ***,simulation results are given to demonstrate the effectiveness of the proposed method.

关键词： covert communication detection Gamma approximation Lambert W function multi-antenna technique

Boosting Hydrogen Storage Performance of MgH_(2. by Oxygen Vacancy-Rich H-V_(2.O_(5) Nanosheet as an Excited H-Pump

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Nano-Micro Letters 2024年第8期16卷 398-416页

作者： Li Ren Yinghui Li Zi Li xi Lin Chong Lu Wenjiang Ding Jianxin Zou National Engineering Research Center of Light Alloys Net Forming&State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Shanghai Engineering Research Center of Mg Materials and Applications&school of Materials science and Engineering Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Center of Hydrogen science Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Instrumental Analysis Center of SJTU Shanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

MgH_(2. is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish ***,intertwined 2. oxygen vacancy-rich V_(2.O_(5) nanosheets(H-V_(2.O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2..The as-prepared MgH_(2.-H-V_(2.O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2. for desorption),and long cycling ***,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 ***,the composites maintain a capacity retention rate of~99%after 100 cycles at 2.5℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2./V catalysts,unique 2. structure of H-V_(2.O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption ***,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2.,but also indirectly affect the activity of the catalytic phase VH_(2./V,thereby further boosting the hydrogen storage performance of MgH_(2..This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2./V on the hydrogen sorption of Mg/MgH_(2..The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.

关键词： Hydrogen storage MgH_(2. V_(2.O_(5)nanosheets Oxygen vacancies VH_(2.