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Nano Research 2024年第9期17卷 8479-8486页

作者： Zixiang Zhao Zheyipei Ma Zizhao Ding Yanqiong Liu Mingwei Zhang chao jiang Institute of Powder Metallurgy Research Central South UniversityChangsha 410083China

To improve the synergistic effect between dielectric and magnetic loss is a practical and effective way in optimizing electromagnetic wave absorbing *** composites of metal particles and carbon ligands derived from metal organic frameworks have gained wide *** this study,co particles and multiwalled carbon nanotubes(cNT)were successfully synthesized covering the surface of silicon carbide(Sic)fibers,and the morphology,interfaces and electromagnetic wave absorption performance were *** sample Sic@co/cNT,the minimum reflection loss value can reach-70.22 dB at 11.21 GHz with the thickness of 2.12 *** effective absorbing bandwidth can reach up to 6.03 GHz with the thickness of 1.71 mm,which covers the entire Ku *** brings more interfaces between co particles and cNTs as well as Sic fibers and co/c *** interfacial polarization has been hugely enhanced,and the microwave absorbing properties have been *** article reports on the impedance matching of magnetic and non-magnetic components and the heterointerface engineering,which can be effective strategy and inspiration to illustrate the relationship between components,structures and functions of electromagnetic wave absorbing materials.

关键词： metal organic frameworks co nanocrystals carbon nanotubes Schottky heterointerfaces synergistic effect

Micromechanical modeling of longitudinal tensile behavior and failure mechanism of unidirectional carbon fiber/aluminum composites involving fiber strength dispersion

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cHINESE JOURNAL OF AERONAUTIcS 2024年第9期37卷 312-327页

作者： Liu, Qipeng jiang, Wengang Gao, Yuehua Wang, Zhenjun Shi, Shanshan Sun, Zhi Nanchang Hangkong Univ Jiangxi Key Lab Forming & Joining Technol Aerosp C Nanchang 330063 Peoples R China Dalian Jiaotong Univ Sch Locomot & Rolling Stock Engn Dalian 116028 Peoples R China Dalian Univ Technol State Key Lab Struct Anal Optimizat & CAE Software Dalian 116024 Peoples R China

This paper examines the longitudinal tensile behavior and failure mechanism of a new unidirectional carbon fiber reinforced aluminum composite through experiments and simulations. A Weibull distribution model was established to describe the fiber strength dispersion based on single-fiber tensile tests for carbon fibers extracted from the composite. The constitutive models for the matrix and interface were established based on the uniaxial tensile and single-fiber pushout tests, respectively. Then, a 3D micromechanical numerical model, innovatively considering the fiber strength dispersion by use of the weakest link and Weibull distribution theories, was established to simulate the progressive failure behavior of the composite under longitudinal tension. Due to the dispersion of fiber strength, the weakest link of the fiber first fractures, and stress concentration occurs in the surrounding fibers, interfaces, and matrix. The maximum stress concentration factor for neighboring fibers varies nonlinearly with the distance from the fractured fiber. Both isolated and clustered fractured fibers are present during the progressive failure process of the composite. The expansion of fractured fiber clusters intensifies stress concentration and material degradation which in turn enlarges the fractured fiber clusters, and their mutual action leads to the final collapse of the composite. (c) 2024 Production and hosting by Elsevier Ltd. on behalf of chinese Society of Aeronautics and Astronautics. This is an open access article under the cc BY-Nc-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Fiber reinforced metals Finite element method 3D micromechanical model Fiber strength dispersion Longitudinal tension Progressive failure METAL-MATRIX cOMPOSITES REINFORcED ALUMINUM DEFORMATION MEcHANISMS HYBRIDIZATION FABRIcATION PULLOUT AL2O3 ALLOY

PURP: A Scalable System for Predicting Short-Term Urban TrafficFlow Based on License Plate Recognition Data

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Big Data Mining and Analytics 2024年第1期7卷 171-187页

作者： Shan Zhang Qinkai jiang Hao Li Bin cao Jing Fan School of computer Science and Technology Zhejiang University of TechnologyHangzhou 310000China

Accurate and efficient urban traffic flow prediction can help drivers identify road traffic conditions in real-time,consequently helping them avoid congestion and accidents to a certain ***,the existing methods for real-time urban traffic flow prediction focus on improving the model prediction accuracy or efficiency while ignoring the training efficiency,which results in a prediction system that lacks the scalability to integrate real-time traffic flow into the training *** conduct accurate and real-time urban traffic flow prediction while considering the latest historical data and avoiding time-consuming online retraining,herein,we propose a scalable system for Predicting short-term URban traffic flow in real-time based on license Plate recognition data(PURP).First,to ensure prediction accuracy,PURP constructs the spatio-temporal contexts of traffic flow prediction from License Plate Recognition(LPR)data as effective ***,to utilize the recent data without retraining the model online,PURP uses the nonparametric method k-Nearest Neighbor(namely KNN)as the prediction framework because the KNN can efficiently identify the top-k most similar spatio-temporal contexts and make predictions based on these contexts without time-consuming model retraining *** experimental results show that PURP retains strong prediction efficiency as the prediction period increases.

关键词： traffic flow prediction k-Nearest Neighbor(KNN) License Plate Recognition(LPR)data spatio-temporalcontext

Accelerating H^(*)desorption of hollow Mo_(2)c nanoreactor via in-situ grown carbon dots for electrocatalytic hydrogen evolution

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Journal of Energy chemistry 2024年第9期96卷 464-471页

作者： Mengmeng Liu Yuanyuan jiang Zhuwei cao Lulu Liu Hong chen Sheng Ye School of Materials and chemistry Anhui Agricultural UniversityHefei 230036AnhuiChina

Molybdenum carbide(Mo_(2)c)is a promising non-noble metal electrocatalyst with electronic structures similar to Pt for hydrogen evolution reaction(HER).However,strong H^(*)adsorption at the Mo sites hinders the improvement of HER ***,we synthesized monodisperse hollow Mo_(2)c nanoreactors,in which the carbon dots(cD)were in situ formed onto the surface of Mo_(2)c through carburization *** to finite element simulation and analysis,the cD@Mo_(2)c possesses better mesoscale diffusion properties than Mo_(2)c *** optimized cD@Mo_(2)c nanoreactor demonstrates superior HER performance in alkaline electrolyte with a low overpotential of 57 mV at 10 mA cm^(−2),which is better than most Mo_(2)c-based ***,cD@Mo_(2)c exhibits excellent electrochemical stability during 240 h,confirmed by operando Raman and X-ray diffraction(XRD).Density functional theory(DFT)calculations show that carbon dots cause the d-band center of cD@Mo_(2)c to shift away from Fermi level,promoting water dissociation and the desorption of H^(*).This study provides a reasonable strategy towards high-activity Mo-based HER eletrocatalysts by modulating the strength of Mo–H bonds.

关键词： Mo_(2)c nanoreactor carbon dots H^(*)desorption Electrocatalytic hydrogen evolution

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Experimental and theoretical investigation of sulfur-doped g-c_(3)N_(4)nanosheets/Feco_(2)O_(4)nanorods S-scheme heterojunction for photocatalytic H_(2)evolution

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Nano Research 2024年第9期17卷 8007-8016页

作者： Haitao Wang Lianglang Yu Jiahe Peng Jing Zou Weiping Gong Jizhou jiang School of chemistry and Environmental Engineering School of Environmental Ecology and Biological EngineeringKey Laboratory of Green Chemical Engineering Process of Ministry of EducationEngineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationNovel Catalytic Materials of Hubei Engineering Research CenterWuhan Institute of TechnologyWuhan 430205China Guangdong Provincial Key Laboratory for Electronic Functional Materials and Devices Huizhou UniversityHuizhou 516007China

g-c_(3)N_(4)emerges as a promising metal-free semiconductor photocatalyst due to its cost-effectiveness,facile synthesis,suitable visible light response,and robust thermal ***,its practical application in photocatalytic hydrogen evolution reaction(HER)is impeded by rapid carrier recombination and limited light absorption *** this study,we successfully develop a novel g-c_(3)N_(4)-based step-scheme(S-scheme)heterojunction comprising two-dimensional(2D)sulfur-doped g-c_(3)N_(4)nanosheets(ScN)and one-dimensional(1D)Feco_(2)O_(4)nanorods(Feco_(2)O_(4)),demonstrating enhanced photocatalytic HER *** engineered ScN/Feco_(2)O_(4)S-scheme heterojunction features a well-defined 2D/1D heterogeneous interface facilitating directed interfacial electron transfer from Feco_(2)O_(4)to ScN,driven by the lower Fermi level of ScN compared to Feco_(2)O_(4).This establishment of electron-interacting 2D/1D S-scheme heterojunction not only facilitates the separation and migration of photogenerated carriers,but also enhances visible-light absorption and mitigates electron-hole pair *** structure analysis and density functional theory calculations corroborate that the carrier migration in the ScN/Feco_(2)O_(4)photocatalyst adheres to a typical S-scheme heterojunction mechanism,effectively retaining highly reactive photogenerated ***,the optimized ScN/Feco_(2)O_(4)heterojunction exhibits a substantially high hydrogen production rate of 6303.5μmol·g^(-1)·h^(-1)under visible light excitation,which is 2.4 times higher than that of the ***,the conjecture of the S-scheme mechanism is confirmed by in situ XPS *** 2D/1D S-scheme heterojunction established in this study provides valuable insights into the development of high-efficiency carbon-based catalysts for diverse energy conversion and storage applications.

关键词： g-c_(3)N_(4) Feco_(2)O_(4) S-scheme heterojunction photocatalytic hydrogen evolution reaction(HER)

Quantifying the solid electrolyte interphase stress induced capacity fading of lithium-ion batteries via a multiscale mechanical-electrochemical coupling model

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Science china Technological Sciences 2024年第10期67卷 3168-3181页

作者： HE YaoLong XU Peng jiang DengFeng HU HongJiu LI DaWei SHI SiQi Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai University Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai Frontier Science center of Mechanoinformatics Shanghai University School of Mechanical Engineering University of Shanghai for Science and Technology School of Materials Science and Engineering Shanghai University Materials Genome Institute Shanghai University

The solid electrolyte interphase（SEI） is widely recognized as a critical factor leading to the capacity fading of lithium-ion batteries（LIBs）. Although SEI stress-related mechanical failure caused by the expansion or contraction of active materials upon cycles is well documented, previously reported SEI components and overpotential varying phenomena due to SEI stress and their effects on the electrochemical performance are poorly understood. Here, we establish a quantitative correlation between capacity fading and the SEI stress by considering its effects on side reactions, especially SEI component evolution, in a multiscale mechanical-electrochemical coupling model. Furthermore, the capacity fading behaviors of two typical cells（Li[NiMnco]O2as the cathode, and graphite and silicon as the anode, respectively） were adopted as numerical examples to demonstrate its potential utility and applications. Stress within the SEI was indeed found to play a predominant role in the capacity fading of the graphite and silicon anodes, resulting in 27% and 69% of the total capacity loss after 200 and 100 cycles at 1 c, respectively. This study provides valuable mechanical insights into the variations of SEI properties related to the capacity degradation and SEI optimization and design for LIBs.

关键词： solid electrolyte interphase capacity fading multiscale mechanical-electrochemical coupling stress analysis

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High Seebeck coefficient Thermally chargeable Supercapacitor with Synergistic Effect of Multichannel Ionogel Electrolyte and Ti3c2Tx MXene-Based composite Electrode

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 367-377页

作者： chen, Zhongming Du, Zhijian Li, La jiang, Kai chen, Di Shen, Guozhen Univ Sci & Technol Beijing Sch Math & Phys Beijing 100083 Peoples R China Beijing Inst Technol Sch Integrated Circuits & Elect Beijing 100081 Peoples R China chinese PLA Chinese PLA Gen Hosp Inst Hepatobiliary Surg Chinese PLA Fac Hepatopancreato Biliary Surg Beijing 100853 Peoples R China chinese PLA Key Lab Digital Hepetobiliary Surg Beijing 100853 Peoples R China

Thermally chargeable supercapacitors can collect low-grade heat generated by the human body and convert it into electricity as a power supply unit for wearable electronics. However, the low Seebeck coefficient and heat-to-electricity conversion efficiency hinder further application. In this paper, we designed a high-performance thermally chargeable supercapacitor device composed of ZnMn2O4@Ti3c2Tx MXene composites (ZMO@Ti3c2Tx MXene) electrode and UIO-66 metal-organic framework doped multichannel polyvinylidene fluoridehexafluoro-propylene ionogel electrolyte, which realized the thermoelectric conversion and electrical energy storage at the same time. This thermally chargeable supercapacitor device exhibited a high Seebeck coefficient of 55.4 mV K-1, thermal voltage of 243 mV, and outstanding heat-to-electricity conversion efficiency of up to 6.48% at the temperature difference of 4.4 K. In addition, this device showed excellent charge-discharge cycling stability at high-temperature differences (3 K) and low-temperature differences (1 K), respectively. connecting two thermally chargeable supercapacitor units in series, the generated output voltage of 500 mV further confirmed the stability of devices. When a single device was worn on the arm, a thermal voltage of 208.3 mV was obtained indicating the possibility of application in wearable electronics.

关键词： ionogel electrode Soret effect thermally chargeable supercapacitor Ti3c2Tx MXene UIO-66 MOF GELS

A comprehensive fluid-solid coupling dynamic simulation for spatiotemporal distribution of regression rate in hybrid rocket motors

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cHINESE JOURNAL OF AERONAUTIcS 2024年第9期37卷 100-112页

作者： Wei, Tianfang cai, Guobiao Tian, Hui Meng, Xiangyu jiang, Xianzhu Gu, Xiaoming Beihang Univ Sch Astronaut Beijing 100191 Peoples R China Minist Educ Key Lab Spacecraft Design Optimizat & Dynam Simula Beijing 100191 Peoples R China

The spatiotemporal distribution characteristics of the regression rate are crucial aspects of the research on Hybrid Rocket Motor (HRM). This study presents a pioneering effort in achieving a comprehensive numerical simulation of fluid dynamics and heat transfer in both the fluid and solid regions throughout the entire operation of an HRM. To accomplish this, a dynamic grid technique that incorporates fluid-solid coupling is utilized. To validate the precision of the numerical simulations, a firing test is conducted, with embedded thermocouple probes being used to measure the inner temperature of the fuel grain. The temperature variations in the solid fuel obtained from both experiment and simulations show good agreement. The maximum combustion temperature and average thrust obtained from the simulations are found to deviate from the experimental results by only 3.3% and 2.4%, respectively. Thus, it can be demonstrated that transient numerical simulations accurately capture the fluid-solid coupling characteristics and transient regression rate. The dynamic simulation results of inner flow field and solid region throughout the entire working stage reveal that the presence of vortices enhances the blending of combustion gases and improves the regression rate at both the front and rear ends of the fuel grain. In addition, oscillations of the regression rate obtained in the simulation can also be well corresponded with the corrugated surface observed in the experiment. Furthermore, the zero-dimension regression rate formula and the formula describing the axial location dependence of the regression rate are fitted from the simulation results, with the corresponding coefficients of determination (R-2) of 0.9765 and 0.9298, respectively. This research serves as a reference for predicting the performance of HRM with gas oxygen and polyethylene, and presents a credible way for investigating the spatiotemporal distribution of the regression rate. (c) 2024 Production and hosti

关键词： Hybrid Rocket Motor (HRM) Transient numerical simulation Fluid-solid coupling heat transfer Spatiotemporal distribution of regression rate Dynamic grid FLAME MODEL

Direct enantioselective reduction of c=c bond of β-polyfluoro-alkylated enones via asymmetric photoredox catalysis

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Science china chemistry 2024年第6期67卷 2016-2021页

作者： Linghong Zhang Jin Ma Xu Ban Xiaowei Zhao Yanli Yin Zhiyong jiang Key Laboratory of Natural Medicine and Immuno-Engineering of Henan Province Henan UniversityKaifeng475004China School of chemistry and chemical Engineering Henan Normal UniversityPingyuan LaboratoryXinxiang453007China college of Advanced Interdisciplinary Science and Technology Henan University of TechnologyZhengzhou450001China

Direct enantioselective reduction of the c=c bond ofβ-polyfluoro-alkylated enones is an important but long-pending subject in asymmetric ***,we report on the viability of visible light-driven cooperative photoredox and chiral hydrogenbonding catalysis to effectively address this challenge,as a variety of products are obtained in high yields(up to 85%)with good to excellent enantioselectivities(up to 98%ee).The formation of thermodynamically favorable enol intermediates after double single-electron reduction represents the center of the ***,the utility of the current method is validated by the convenient regio-specific and-diverse synthesis of various deuterated derivatives for these products using inexpensive D_(2)O as the deuterium source.

关键词： photoredox catalysis Br?nsted acids asymmetric reduction enantioselective protonation azaarenes

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Advances in poly(heptazine imide)/poly(triazine imide) photocatalyst

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chinese chemical Letters 2024年第10期35卷 128-151页

作者： Haojie Song Laiyu Luo Siyu Wang Guo Zhang Baojiang jiang Key Laboratory of Functional Inorganic Material chemistry Ministry of Education of the People's Republic of China School of Chemistry and Materials Science Heilongjiang University

Polymeric carbon nitride （PcN） has garnered increasing attention as a metal-free photocatalyst with a suitable band *** efforts to enhance its photocatalytic performance,researchers have examined various PcN materials,including poly（heptazine imide）(PHI) and poly（triazine imide）(PTI),two isomers within the PcN family that exhibit distinct and superior photocatalytic activity compared to other *** challenge,however,lies in the common practice among researchers to categorize PHI and PTI along with other PcN types under the overarching term“g-c3N4,”which significantly impedes optimization *** objective of this review is to provide comprehensive insights into the structural features,photoelectrochemical properties,and effective characterization methods employed for distinguishing between PHI and PTI *** review also summarizes various optimization strategies,such as crystallinity adjustments,defect engineering,morphology control,constructing heterojunction,and atomic-level metal loading dispersion,to elevate the photocatalytic activity of PHI and PTI,in addition to summarizing the history of carbon nitride ***,this review highlights the primary applications of PHI and PTI,encompassing nitrogen fixation,biomass conversion,organic synthesis,cO2reduction,pollutant degradation,H2O2production,and photocatalytic water ***,the prospects and challenges associated with further advancing PHI and PTI are thoroughly examined.

关键词： Application Modification Photocatalytic Poly(heptazine imide) Poly(triazine imide)