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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： N.IQBAL J.CHOI S.F.SHAH C.LEE S.LEE department of mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyCo_(z)O_(2)(x≥0.8)(NMC)particles with poly(3,4-ethylenedioxythiophene)(PEDOT).The simulation results show that the coating of primary NMC particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more ***,the lower stiffness,higher ionic conductivity,and larger thickness of the coating layer improve the stress *** paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMC active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation Ni-rich LiNixMnyCo_(z)O_(2)(x>0.8)(NMC)

A shield of defense:Developing ballistic composite panels with effective electromagnetic interference shielding absorption

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Defence Technology（防务技术） 2024年第5期35卷 123-136页

作者： Nisrin Rizek Abdelal mechanical engineering department Jordan University of Science and TechnologyIrbid 22110Jordan

The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference(EMI)shielding capabilities through *** fiber-reinforced epoxy composite panels,each with a different fabric material and stacking sequence,have been fabricated using a hand-layup vacuum bagging *** panels made of Kevlar and glass fibers,referred to as(K-NIJ)and(G-NIJ),have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA(9 mm×19 mm FMJ 124 g)*** panels,namely,a hybrid of Kevlar and glass(H-S),glass with ceramic particles(C-S),and glass with recycled rubber(R-S)have been impacted by the bullet at the center,while the fourth panel made of glass fiber(G-S)has been impacted at the *** shielding properties have been measured in the X-band frequency range via the reflection-transmission *** indicate that four panels(K-NIJ,G-NIJ,H-S,and G-S)are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural ***,under such conditions,these panels may experience localized delamination with variable *** EMI measurements reveal that the highest absorptivity observed is 88% for the KNIJ panel at 10.8 GHz,while all panels maintain an average absorptivity above 65%.All panels act as a lossy medium with a peak absorptivity at different frequencies,with K-NIJ and H-S panels demonstrating the highest *** summary,the study results in the development of a novel,costeffective,multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding *** material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency;no bullet

关键词： Ballistic FRP composite EMI shielding Absorptivity CT-Scan NIJ test Bullet Defense

Comparative analysis of single-crater parameters in ultrasonic-assisted and unassisted micro-EDM of Ti6Al4V using discharge plasma imaging

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Nanotechnology and Precision engineering 2024年第2期7卷 11-24页

作者： Sohaib Raza Chandrakant Nirala department of mechanical engineering Indian Institute of Technology RoparPunjab 140001India

Ultrasonic-assisted micro-electro-discharge machining(EDM)has the potential to enhance processing responses such as material removal rate(MRR)and surface *** understand the reasons for this enhancement,the physical mechanisms responsible for the individual discharges and the craters that they form need to be *** work examines features of craters formed by single discharges at various parameter values in both conventional and ultrasonic-assistedEDM of ***-speed imaging of the plasma channel is performed,and data on the individual discharges are captured in real-time.A 2D axisymmetric model using finite element software is established to model crater *** the basis of simulation and experimental results,a comparative study is then carried out to examine the effects of ultrasonic vibrational assistance on crater *** every set ofEDM parameters,the crater diameter and depth from a single discharge are found to be higher in ultrasonic-assistedEDM than in conventional*** improved crater geometry and the reduced bulge formation at the crater edges are attributed to the increased melt pool velocity and temperature predicted by the model.

关键词： Ultrasonic vibration Discharge crater Plasma diameter Single discharge

Performance and combustion study of a low heat rejection engine running with biogas–diethyl ether–diesel

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Waste Disposal and Sustainable Energy 2024年第1期6卷 151-162页

作者： Sanjaya K.Mishra Premananda Pradhan Shakti P.Jena department of mechanical engineering S‘O’A Deemed to be UniversityBhubaneswar751030India

The present research focuses on addressing the faster depletion of fossil fuels and environmental pollution in addition to the energy crisis that hinders the progress of a *** the current research,waste banana leaves were considered as substrates for biogas *** is taken as the primary fuel in dual fuel(DF)operations to maximize possible diesel *** performance and combustion assessment were executed in a low heat rejection(LHR)engine using 5%diethyl ether by volume blended with diesel(5DEE)as pilot *** combustion attributes of the engine reveal that the apex of net heat release rate(NHRR)curve retarded a bit as compared to apex of base *** peak cylinder pressure was noted to be 6.19 MPa in the LHR engine running with 5DEE+biogas at 11.7°crank angle(CA)after top dead center(aTDC)compared to 5.23 MPa for the diesel alone operation at the same *** apex point for NHRR was observed to be 54.51 J(°)^(−1)for 5DEE+biogas in LHR engine positioned at 3.2°*** brake thermal efficiency at full engine load operation decreased by 12.7%and 5.2%for biogas substitutions of 0.8 kg h^(−1)with diesel and 5DEE,respectively,compared to the base *** smoke opacity and nitric oxide emissions were reduced during the DF run accompanied by diethyl ether as a fuel additive.

关键词： Biogas Banana leaves Coating Diesel engine Diethyl ether Exhaust emissions

Breakdown of effective medium theory:A study of photonic spin Hall effect in deep-subwavelength all-dielectric multilayers

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 173-174页

作者： Yongmin Liu department of mechanical and Industrial engineering Northeastern UniversityBoston 02115USA department of Electrical and Computer engineering Northeastern UniversityBoston 02115USA

Effective medium theory(EMT)has been widely applied in material science,electromagnetics and photonics to determine the effective material properties for inhomogeneous composites comprising subwavelength *** versatility of this foundational approach has been established through its application in classical Maxwell-Garnet models,which encompass relatively simple structures。

关键词： composites theory dielectric

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Online Pareto optimal control of mean-field stochastic multi-player systems using policy iteration

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Science China(Information Sciences) 2024年第4期67卷 21-37页

作者： Xiushan JIANG Yanshuang WANG Dongya ZHAO Ling SHI College of New Energy China University of Petroleum(East China) department of Electronic and Computer engineering Hong Kong University of Science and Technology

In this study, the Pareto optimal strategy problem was investigated for multi-player mean-field stochastic systems governed by It? differential equations using the reinforcement learning(RL) method.A partially model-free solution for Pareto-optimal control was derived. First, by applying the convexity of cost functions, the Pareto optimal control problem was solved using a weighted-sum optimal control problem. Subsequently, using on-policy RL, we present a novel policy iteration(PI) algorithm based on the Hrepresentation technique. In particular, by alternating between the policy evaluation and policy update steps,the Pareto optimal control policy is obtained when no further improvement occurs in system performance,which eliminates directly solving complicated cross-coupled generalized algebraic Riccati equations(GAREs).Practical numerical examples are presented to demonstrate the effectiveness of the proposed algorithm.

关键词： mean-field stochastic systems Pareto optimal control policy iteration scheme $\mathcal{H}$-representation

Geochemical fingerprints and hydrocarbon potential of Paleocene mudrocks in the Tano Basin, Ghana: insights from biomarkers and stable carbon isotopes

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Acta Geochimica 2024年第2期43卷 255-279页

作者： Kojo Amoako Nancy Pearl Osei-Boakye Ningning Zhong N’Guessan Francois De Sales Konan Gordon Foli Prince Opoku Appau Clifford Fenyi Ebenezer Apesegah Research Group for Marine Geochemistry(ICBM-MPI Bridging Group) Institute for Chemistry and Biology of the Marine Environment(ICBM)Carl von Ossietzky University OldenburgAmmerlander Heerstr.26129 OldenburgGermany State Key Laboratory of petroleum Resources and Prospecting College of GeosciencesChina University of PetroleumBeijing 102249China department of Geological engineering Faculty of Civil and Geo-EngineeringKwame Nkrumah University of Science and TechnologyKumasiGhana Ghana National gas Company 225 Osibisa CloseAirport WestAccraGhana petroleum Corporation GNPCPMBPetroleum HouseTemaGhana

The Paleocene mudrocks in Ghana’s Tano Basin have received limited attention despite ongoing efforts to explore hydrocarbon resources.A thorough geochemical analysis is imperative to assess these mudrocks’petroleum generation potential and formulate effective exploration *** this study,a comprehensive geochemical analysis was carried out on ten Paleocene rock cuttings extracted from TP-1,a discovery well within the Tano *** analytical techniques,including total organic carbon(TOC)analysis,Rock–Eval pyrolysis,gas chromatography-mass spectrometry,and isotope ratio-mass spectrometry,were employed to elucidate their hydrocar-bon potential and organic ***ﬁndings in this study were subsequently compared to existing geochemical data on Paleocene source rocks in the South Atlantic marginal *** results indicated that the Paleocene samples have TOC content ranging from 0.68 to 2.93 wt%.The prevalent kerogen types identiﬁed in these samples were Type Ⅱ and Type Ⅲ.Molecular and isotope data suggest that the organic matter found in the Paleocene mudrocks can be traced back to land plants and lower aquatic *** mudrocks were deposited in a transi-tional environment withﬂuctuating water salinity,charac-terized by sub-oxic redox *** indices,both bulk and molecular,indicated a spectrum of maturity levels within the Paleocene mudrocks,spanning from immature to marginally mature,with increasing maturity observed with greater *** comparison,the organic composition and depositional environments of Paleocene source rocks in the Tano Basin closely resemble those found in the Niger Delta Basin,Douala,and Kribi-Campo Basins,the Kwanza Formation in Angola,and certain Brazilian marginal ***,it is worth noting that Paleocene source rocks in some of the basins,such as the Niger Delta and Brazilian marginal basins,exhibit rela-tively higher thermal maturity levels compared to those observed in the current Paleocene samp

关键词： Paleocene source rocks Source input Depositional environment Thermal maturity Hydrocarbon potential Tano Basin West Africa

Broadband angular spectrum analog processors based on all-dielectric metasurfaces

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 188-190页

作者： Lin Deng Yongmin Liu department of Electrical and Computer engineering Northeastern UniversityBoston 02115USA department of mechanical and Industrial engineering Northeastern UniversityBoston 02115USA

Digital signal processors are extensively used to execute mathematical operations and advanced computational tasks on digital ***,they suffer from several inherent limitations,including low speed,high energy consumption,and large memory requirements,because of the hardware bottleneck and the imperative conversion between digital and analogue signals.

关键词： dielectric spectrum hardware

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Numerical modeling of fracture propagation of supercritical CO_(2)compound fracturing

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Journal of Rock Mechanics and Geotechnical engineering 2024年第7期16卷 2607-2628页

作者： Hao Chen Yong Kang Wanchun Jin Changhai Li Can Cai School of mechanical engineering Southwest Petroleum UniversityChengdu610500China Laboratory of High-pressure Jet Theory and Application Technology Southwest Petroleum UniversityChengdu610500China Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan UniversityWuhan430072China Sinopec International petroleum Exploration and Production Corporation Beijing 100029China

The exploitation of shale gas is promising due to depletion of the conventional energy and intensification of the greenhouse *** this paper,we proposed a heat-fluid-solid coupling damage model of supercritical CO_(2)(SC-CO_(2))compound fracturing which is expected to be an efficient and environmentally friendly way to develop shale *** coupling model is solved by the finite element method,and the results are in good agreement with the analytical solutions and fracturing *** on this model,the fracture propagation characteristics at the two stages of compound fracturing are studied and the influence of pressurization rate,in situ stress,bedding angle,and other factors are *** results show that at the SC-CO_(2)fracturing stage,a lower pressurization rate is conducive to formation of the branches around main fractures,while a higher pressurization rate inhibits formation of the branches around main fractures and promotes formation of the main *** bedding and in situ stress play a dominant role in the fracture *** the in situ stress ratio(sx/sy)is 1,the presence of bedding can reduce the initiation pressure and failure ***,it will cause the fracture to propagate along the bedding direction,reducing the fracture *** rocks without bedding,hydraulic fracturing has the lengthening and widening effects for SC-CO_(2)induced *** shale,fractures induced at the hydraulic fracturing stage are more likely to be dominated by in situ stresses and have a shorter reorientation ***,fracture branches propagating along the maximum principal stress direction may be generated around the main fractures induced by SC-CO_(2)at the hydraulic fracturing *** the branches converge with the main fractures,fracture zones are easily formed,and thus the fracture complexity and damage area can be significantly *** results are instructive for the design and application of SC-CO_(2

关键词： Compound fracturing Fracture propagation Finite element method Damage evolution

Deep neural network-enabled battery open-circuit voltage estimation based on partial charging data

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Journal of Energy Chemistry 2024年第3期90卷 120-132,I0005页

作者： Ziyou Zhou Yonggang Liu Chengming Zhang Weixiang Shen Rui Xiong State Key Laboratory of mechanical Transmission for Advanced Equipment&College of mechanical and Vehicle engineering Chongqing UniversityChongqing 400000China department of Vehicle engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China department of Electrical engineering Harbin Institute of TechnologyHarbin 150000HeilongjiangChina School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthornVictoria 3122Australia

Battery management systems(BMSs) play a vital role in ensuring efficient and reliable operations of lithium-ion *** main function of the BMSs is to estimate battery states and diagnose battery health using battery open-circuit voltage(OCV).However,acquiring the complete OCV data online can be a challenging endeavor due to the time-consuming measurement process or the need for specific operating conditions required by OCV estimation *** addressing these concerns,this study introduces a deep neural network-combined framework for accurate and robust OCV estimation,utilizing partial daily charging *** incorporate a generative deep learning model to extract aging-related features from data and generate high-fidelity OCV *** analysis is employed to identify the optimal partial charging data,optimizing the OCV estimation precision while preserving exceptional *** validation results,using data from nickel-cobalt-magnesium(NCM) batteries,illustrate the accurate estimation of the complete OCV-capacity curve,with an average root mean square errors(RMSE) of less than 3 *** this level of precision for OCV estimation requires only around 50 s collection of partial charging *** validations on diverse battery types operating under various conditions confirm the effectiveness of our proposed *** cases of precise health diagnosis based on OCV highlight the significance of conducting online OCV *** method provides a flexible approach to achieve complete OCV estimation and holds promise for generalization to other tasks in BMSs.

关键词： Lithium-ion battery Open-circuit voltage Health diagnosis Deep learning