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lightweight Si_(3)N_(4)@SiO_(2. ceramic foam for thermal insulation and electromagnetic wave transparency

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Nano Research 2024年第5期17卷 4298-4306页

作者： Zongwei Tong Xiangjie Yan Yuexiang Wang Kexun li Weihai ma China-Blarus Belt and Road Joint Laboratory on Electromagnetic Environment Effect the 33rd Research Institute of ChinaElectronics Technology Group CorporationTaiyuan 030032China Key Laboratory for Advanced Ceramics and machining Technology of Ministry of Education School of Material Science and EngineeringTianjin UniversityTianjin 300072China Department of materials Science and Engineering Jinzhong UniversityJinzhong 030619China

Increasing porosity is one of the most direct ways to improve the thermal insulation and dielectric properties of *** now,many wet methods for preparing Si_(3)N_(4) ceramic foams usually face the problems of complex rheology,long period,and expensive cost,and the reported pore sizes of Si_(3)N_(4) ceramic foams are typically micron-grade,resulting in a lack of competitiveness in thermal insulation and wave-transparent *** this paper,the Si_(3)N_(4)@SiO_(2. ceramic foams were prepared using an efficient dry-method,which combined three processes of low temperature chemical vapor deposition(LTCVD),template,and isostatic *** method has the advantages of simple operation and short preparation period,and can realize near-net size molding and mass *** addition,the evolution mechanisms of honeycomb microstructure and composition of Si_(3)N_(4)@SiO_(2. ceramic foam during sintering were studied by chemical reaction *** as-prepared Si_(3)N_(4)@SiO_(2. ceramic foam possesses low density(0.377 g·cm^(-3)),high compressive strength(7.5 MPa),low thermal conductivity(0.0808 W·m^(-1)·K^(-1)),and excellent dielectric properties(ε2.tanδmaximum working temperature in air can reach up to 1100℃.It will be recommended to be applied in the interlayer of Si_(3)N_(4) ceramic radome to improve its thermal insulation and electromagnetic wave transparency performances.

关键词： silicon nitride ceramic foam honeycomb microstructure dielectric properties thermal insulation

Alloy/layer double hydroxide interphasic synergy via nano-heterointerfacing for highly reversible CO_(2.redox reaction in li-CO_(2.batteries

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Nano Research 2024年第6期17卷 5206-5215页

作者： Tianzhen Jian Wenqing ma Jiagang Hou Jianping ma Xianhong li Haiyang Gao Caixia Xu Hong liu Institute for Advanced Interdisciplinary Research(iAIR) Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongSchool of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China Kyiv College at Qilu University of Technology Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353China State Key Laboratory of Crystal materials Shandong UniversityJinan 250100China Shandong Sacred Sun Power Sources Co. Ltd.Qufu 273100China

li-CO_(2.batteries are among the most intriguing techniques for balancing the carbon cycle,but are challenged by the annoyed thermodynamic barrier of the li_(2.CO_(3)decomposition ***,we demonstrate the electrocatalytic performances of two-dimensional(2.)CoAl-layer double hydroxide(LDH)nanosheets can be significantly improved by trans-dimensional crosslinking with three-dimensional(3D)multilevel nanoporous(MP)-RuCoAl alloy(MP-RuCoAl alloy⊥CoAl-LDH).The MP-RuCoAl alloy⊥CoAl-LDH with multiscale pore channels and abundant nano-heterointerface is directly prepared by controllable etching Al from a Ru-Co-Al master alloy along with simultaneous partial oxidization of Al and Co *** MP-RuCoAl is composed of various intermetallic compounds and Ru with abundant grain boundaries,and forms numerous heterointerface with 2. CoAl-LDH *** multiscale porous metallic network benefits mass and electron transportation as well as discharge product storage and enables a rich multiphase reaction *** situ differential electrochemical mass spectrometry shows that the mass-to-charge ratio in the charging process is~0.733 which is consistent with the theoretical value of 3/4,stating that the reversible co-decomposition of li_(2.CO_(3)and C can be achieved with the MP-RuCoAl alloy⊥*** Ketjen black(KB)/MP-RuCoAl⊥CoAl-LDH battery demonstrates a high cyclability for over 2.70 h(2.7 cycles)with a lower voltage gap stabilized at~1.3 V at 2.0 ma·g^(−1).Our findings here provide useful guidelines for developing high efficiency transition metal based electrocatalysts by coupling with conductive porous substrate for impelling the development of practical li-CO_(2.battery systems.

关键词： heterojunction interface nanoporous li-CO_(2.battery dealloying

A high-resolution dataset for lower atmospheric process studies over the Tibetan Plateau from 1981 to 2.2.

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Big Earth Data 2024年第3期8卷 540-565页

作者： Fei li Shupo ma Jinhuan Zhu Han Zou Peng li libo Zhou Department of Lower Atmospheric Observation Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina

ABSTRACT A high-resolution meteorological dataset(≤10 km)over the Tibetan Plateau(TP)is the foundation for investigating and predicting the weather and climate over *** TP Subregional Dynamical Downscaling(TPSDD)dataset is a newly developed high-spatial-temporal resolution gridded dataset for land‒air exchange pro-cesses and lower atmospheric structure studies over the whole TP region,taking the climate characteristics of each TP subregion into *** dataset spans from 1981 to 2.2.,covering the TP with a temporal resolution of 2.hr and spatial resolution of 10 *** elements of the dataset include near-surface land-air exchange parameters,such as downward/upward long-wave/shortwave radiation flux,sensible heat flux,latent heat flux,*** addition,the vertical distributions of 3-dimensional wind,temperature,humidity,and pressure from the surface to the lower stratosphere are also *** evaluations were con-ducted to verify the performance of the TPSDD dataset by compar-ing TPSDD/reanalysis with surface and vertical observations through the calculation of statistical *** results demonstrate the accuracy and superiority of this dataset against reanalysis data,which provides great potential for future climate change research.

关键词： Tibetan Plateau WRF model dynamical downscaling land‒air interaction the lower atmosphere

Novel process for facile preparation of mesoporous silica-based materials with controllable pore structure from coal fly ash Author links open overlay panel

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Particuology 2024年第8期91卷 128-137页

作者： Jian-ming Gao Zhen li Shujia ma Yuanyuan Zhang Fangqin Cheng Institute of Resources and Environment Engineering State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste ResourcesShanxi Collaborative Innovation Center of High Value-added Utilization of Coal-related WastesShanxi UniversityTaiyuan 030006China

Extraction of silica from fly ash to produce mesoporous silica materials is one of the most important utilization *** silica could not be synthesized on a large-scale by conventional sol-gel *** this paper,facile preparation of mesoporous silica with controllable pore structure from fly ash by the template-free process via two steps of mineral phase transformation and selective acid etching was *** influence of crystalline structure and acid etching degree on structure of as-synthesized mesoporous silica materials was revealed,as well as mechanism of crystalline structure transformation and pore structure *** results show that mullite and quartz could be transformed into acid-soluble kaliophilite when fly ash reacted with K_(2.CO_(3)at temperature of 800-1100℃.The hexagonal kaliophilite would be transformed into orthorhombic KAlSiO_(4)-O1 phase when the temperature is controlled at 1100℃.Mesoporous silica with specific surface area of 475.93 m^(2./g and 642.57 m^(2./g could be synthesized from activated fly ash with kaliophilite and KAlSiO_(4)-O1 phase crystalline *** controlling the degree of acid etching,mesoporous silica materials with different pore structures can be *** paper provides a cost-effective and large-scale process for the preparation of mesoporous silica materials with controllable pore structure from solid waste fly ash.

关键词： Fly ash Mesoporous silica Crystal transformation Acid etching Controllable pore structure

Dynamic Resistance and Energy Absorption of Sandwich Beam via a Micro-Topology Optimization

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 146-162页

作者： Shiqiang li Yuwei li Xiaomin ma Jianguang Fang Zhifang liu Zhihua Wang Institute of Applied Mechanics Taiyuan University of TechnologyTaiyuan 030024China Shanxi Key Laboratory of material Strength and Structural Impact Taiyuan University of TechnologyTaiyuan 030024China School of Civil and Environmental Engineering University of Technology SydneySydneyNSW 2007Australia

The current research of sandwich structures under dynamic loading mainly focus on the response characteristic of *** micro-topology of core layers would sufficiently influence the property of sandwich ***,the micro deformation and topology mechanism of structural deformation and energy absorption are *** this paper,based on the bi-directional evolutionary structural optimization method and periodic base cell(PBC)technology,a topology optimization frame work is proposed to optimize the core layer of sandwich *** objective of the present optimization problem is to maximize shear stiffness of PBC with a volume *** effects of the volume fraction,filter radius,and initial PBC aspect ratio on the micro-topology of the core were *** dynamic response process,core compression,and energy absorption capacity of the sandwich beams under blast impact loading were analyzed by the finite element *** results demonstrated that the overpressure action stage was coupled with the core compression *** the same loading and mass per unit area,the sandwich beam with a 2.%volume fraction core layer had the best blast *** filter radius has a slight effect on the shear stiffness and blast resistances of the sandwich *** increasing the filter radius could slightly improve the bending *** changing the initial PBC aspect ratio,there are three ways for PBC evolution:The first is to change the angle between the adjacent bars,the second is to further form holes in the bars,and the third is to combine the first two ***,not all three ways can improve the energy absorption capacity of the *** the aspect ratio of the PBC arbitrarily may lead to worse *** studies are necessary for further detailed *** research proposes a new topology sandwich beam structure by micro-topology optimization,which has sufficient shear *** micro mechanism of structural

关键词： Topology optimization Sandwich beam Impact loading Dynamic resistance Energy absorption Micro mechanism

Research on denoising of joint detection signal of water quality with multi-parameter based on IEEMD

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Optoelectronics Letters 2024年第2期20卷 107-115页

作者： li Wen li Dejian ma Yongyue TIAN Wang WEN Xin li Jie Institute of Mechanical and Electrical Engineering North China University of TechnologyBeijing 100144China1

An improved ensemble empirical mode decomposition(IEEMD) is suggested to process water quality spectral signals in order to address the issue that noise interference makes it difficult to extract and evaluate water quality spectral *** algorithm effectively solves the problems of modal mixing,poor reconstruction accuracy in the empirical mode decomposition(EMD),and a large amount of calculation in the ensemble empirical mode decomposition(EEMD).Based on EEMD,IEEMD firstly preprocesses the original water quality spectral signals,then performs Savitzky-Golay(S-G) smoothing on the decomposed effective intrinsic mode function(IMF) components,and finally reconstructs them to obtain the denoised *** sample data at different concentrations can be accurately analyzed based on the noise-reduced spectral *** this paper,three water quality parameters are used as research objects:benzene(C_(6)H_(6)),benzo(b)fluoranthene(C_(2.)H_(12.),and chemical oxygen demand(COD).The original water quality multi-parameter(C_(6)H_(6),C_(2.)H_(12.,COD) spectral signals were subjected to denoising based on the IEEMD and the water quality multi-parameter joint detection *** signal-to-noise ratio(SNR) and the correlation coefficient(R^(2.) of the fitted curves obtained from the processing of the IEEMD were compared and analyzed with those obtained from the processing of the EMD and the *** experimental results show that the SNR of the spectral signals and the R^(2. of the fitting curve in three water quality parameters have been significantly ***,the IEEMD effectively improves the phenomenon of modal mixing,reduces the amount of calculation,improves the reconstruction accuracy,and provides an important guarantee for the effective extraction of multi-parameter spectral signals of water quality.

关键词： signal parameter noise

Simulation of nuclear isomer production in laser-induced plasma

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matter and Radiation at Extremes 2024年第5期9卷 1-9页

作者： Zhiguo ma Yumiao Wang Yi Yang Youjing Wang Kai Zhao Yixin li Changbo Fu Wanbing He Yugang ma Key Laboratory of Nuclear Physics and Ion-Beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghai 200433China

Nuclear isomers play essential roles in various fields,including stellar nucleosynthesis,nuclear clocks,nuclear batteries,clean nuclear energy,and-ray *** technological advances in high-intensity lasers have made it possible to excite or de-excite nuclear isomers using table-top laser *** a particle-in-cell code,we investigate the interaction of a laser with a nanowire array and calculate the production rates of the^(73m)Ge(E_(1)=13.3 keV)and^(107m)Ag(E_(1)=93.1 keV)***^(73m1)Ge,production by Coulomb excitation is found to contribute a peak efficiency of 1.0×10^(19) particles s^(−1)J^(−1),while nuclear excitation by electron capture(NEEC)contributes a peak of 1.65×10^(11)particles s^(−1)J^(−1).These results indicate a high isomeric production ratio,as well as demonstrating the potential for confirming the existence of NEEC,a long-expected but so far experimentally unobserved fundamental process.

关键词： process. isomers excitation

Fake News Detection Based on Text-Modal Dominance and Fusing Multiple Multi-Model Clues

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Computers, materials & Continua 2024年第3期78卷 4399-4416页

作者： li fang Fu Huanxin Peng Changjin ma Yuhan liu College of Arts and Sciences Northeast Agricultural UniversityHarbin150030China College of Engineering Northeast Agricultural UniversityHarbin150030China

In recent years,how to efficiently and accurately identify multi-model fake news has become more ***,multi-model data provides more evidence but not all are equally ***,social structure information has proven to be effective in fake news detection and how to combine it while reducing the noise information is ***,existing approaches fail to handle these *** paper proposes a multi-model fake news detection framework based on Tex-modal Dominance and fusing Multiple Multi-model Cues(TD-MMC),which utilizes three valuable multi-model clues:text-model importance,text-image complementary,and text-image ***-MMC is dominated by textural content and assisted by image information while using social network information to enhance text *** reduce the irrelevant social structure’s information interference,we use a unidirectional cross-modal attention mechanism to selectively learn the social structure’s features.A cross-modal attention mechanism is adopted to obtain text-image cross-modal features while retaining textual features to reduce the loss of important *** addition,TD-MMC employs a new multi-model loss to improve the model’s generalization *** experiments have been conducted on two public real-world English and Chinese datasets,and the results show that our proposed model outperforms the state-of-the-art methods on classification evaluation metrics.

关键词： Fake news detection cross-modal attention mechanism multi-modal fusion social network transfer learning

The on-chip thermoelectric cooler:advances,applications and challenges

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Chip 2024年第2期3卷 96-108页

作者： Chengjun li Yubo Luo Wang li Boyu Yang Chengwei Sun Wenyuan ma Zheng ma Yingchao Wei Xin li Junyou Yang State Key Laboratory of materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

With the development of 5G technology and increasing chip integration,traditional active cooling methods struggle to meet the growing thermal demands of *** coolers(TECs)have garnered great attention due to their rapid response,significant cooling differentials,strong compatibility,high stability and controllable device *** this review,starting from the fundamental principles of thermoelectric cooling and device design,high-performance thermoelectric cooling materials are summarized,and the progress of advanced on-chip TECs is comprehensively ***,the paper outlines the challenges and opportunities in TEC design,performance and applications,laying great emphasis on the critical role of thermoelectric cooling in addressing the evolving thermal management requirements in the era of emerging chip technologies.

关键词： Chip Thermal management Thermoelectric materials Thermoelectric cooler Cooling performance