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Non-Convex Optimization of Resource Allocation in Fog Computing Using Successive Approximation

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Journal of Systems Science & Complexity 2024年第2期37卷 805-840页

作者： li Shiyong liu Huan li Wenzhe SUN Wei School of Economics and Management Yanshan UniversityQinhuangdao 066000China

Fog computing can deliver low delay and advanced IT services to end users with substantially reduced energy ***,with soaring demands for resource service and the limited capability of fog nodes,how to allocate and manage fog computing resources properly and stably has become the ***,the paper investigates the utility optimization-based resource allocation problem between fog nodes and end users in fog *** authors first introduce four types of utility functions due to the diverse tasks executed by end users and build the resource allocation model aiming at utility ***,for only the elastic tasks,the convex optimization method is applied to obtain the optimal results;for the elastic and inelastic tasks,with the assistance of Jensen’s inequality,the primal non-convex model is approximated to a sequence of equivalent convex optimization problems using successive approximation ***,a two-layer algorithm is proposed that globally converges to an optimal solution of the original ***,numerical simulation results demonstrate its superior performance and *** with other works,the authors emphasize the analysis for non-convex optimization problems and the diversity of tasks in fog computing resource allocation.

关键词： Fog computing non-convex optimization optimal resource allocation successive approximation method utility function

Plastic deformation behavior of a Cu-10Ta alloy under strong impact loading

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Defence Technology（防务技术） 2024年第2期32卷 368-382页

作者： Ping Song Jianghai liu Wenbin li Yiming li Research Institute of Chemical Defense Academy of Military ScienceBeijing102205China Ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjing210094China

In this work,a Cu-10Ta alloy with a copper to tantalum mass ratio of 9:1 is prepared using powder metallurgy *** properties of the alloy,including density,microstructure,melting point,and constant-volume specific heat,are *** the split Hopkinson pressure bar(SHPB)and flyerplate impact experiments,the relationship between equivalent stress and equivalent plastic strain of the material is studied at temperatures of 298-823 K and under strain rates of 1×10^(-3)-5.2×10^(3)s^(-1),and the Hugoniot relationship at impact pressures of 1.46-17.25 GPa and impact velocities of 108-942 m/s is *** of the Cu-10Ta microstructure that occurs during high-strain-rate impact is *** indicate that the Cu-10Ta alloy possesses good thermal stability,and at ambient temperatures of up to 50%its melting point,stress softening of less than 15%of the initial strength is observed.A modified J-C constitutive model is employed to accurately predict the variation of yield strength with strain *** strong impact,the copper phase is identified as the primary source of plastic deformation in the Cu-10Ta alloy,while significant deformation of the high-strength tantalum particles is less ***,the longitudinal wave speed D is found to correlate linearly with the particle velocity u upon strong *** reveals that the sound speed and spallation strength of the alloy increase with increasing impact pressure.

关键词： Cu-10Ta SHPB Plastic deformation Flyer impact Hugoniot relationship

Preparation and Rheological Characterization of Long Chain Branching Polyglycolide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-lin liu Ming-fu Lyu Heng-Yuan Zhang Jian-Ye liu Shi-Jun Zhang Beijing University of Chemical Technology Beijing 100029China SINOPEC(Beijing)Research Institute of Chemical Industry Co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglycolide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher viscosity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical CO_(2)foaming can be carried out successfully.

关键词： Polyglycolide(PGA) Long chain branching(LCB) Rheology

Combined blasting for protection of gob-side roadway with thick and hard roof

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3165-3180页

作者： Qiang fu Jun Yang Yubing Gao Changjiang li Hongxu Song Yuxuan liu Xing Wu State Key Laboratory for Tunnel Engineering China University of Mining and Technology(Beijing)Beijing100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China

The deformation control of surrounding rock in gobside roadway with thick and hard roof poses a significant challenge to the safety and efficiency of coal *** address this issue,a novel approach combining directional and non-directional blasting techniques,known as combined blasting,was *** study focuses on the experimental investigation of the proposed method in the 122108 working face in Caojiatan Coal Mine as the engineering *** initial phase of the study involves physical model experiments to reveal the underlying mechanisms of combined blasting for protecting gob-side roadway with thick and hard *** results demonstrate that this approach effectively accelerates the collapse of thick and hard roofs,enhances the fragmentation and expansion coefficient of gangue,facilitates the filling of the goaf with gangue,and provides support to the overlying strata,thus reducing the subsidence of the overlying strata above the ***,the method involves cutting the main roof into shorter beams to decrease the stress and disrupt stress transmission *** numerical simulations were conducted to corroborate the findings of the physical model experiments,thus validating the accuracy of the experimental ***,field engineering experiments were performed,affirming the efficacy of the combined blasting method in mitigating the deformation of surrounding rock and achieving the desired protection of the gob-side roadway.

关键词： Thick and hard roof Surrounding rock control Combined blasting Fragmentation and expansion support stress relief

Reconfigurable optical neural networks with Plug-and-Play metasurfaces

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Opto-Electronic Advances 2024年第7期7卷 1-3页

作者： Yongmin liu Yuxiao li Department of Mechanical and Industrial Engineering Northeastern UniversityBostonMassachusetts 02115USA Department of Electrical and Computer Engineering Northeastern UniversityBostonMassachusetts 02115USA

In a very recent study,*** Huang and co-workers proposed and demonstrated reconfigurable optical neural networks based on cascaded *** fixing one metasurface and switching the other pluggable metasurfaces,the neural networks,which operate at near-infrared wavelengths,can perform distinct recognition tasks for handwritten digits and fashion *** innovative device opens up an avenue for all-optical,high-speed,low-power,and multifunctional artificial intelligence systems.

关键词： surfaces networks neural

Engineering single-atom Mn on nitrogen-doped carbon to regulate lithium-peroxide reaction kinetics for rechargeable lithium-oxygen batteries

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Journal of Energy Chemistry 2024年第7期94卷 199-207页

作者： Yaling Huang Yong liu Yang liu Chenyang Zhang Wenzhang li Jie li School of Chemistry and Chemical Engineering Central South UniversityChangsha 410083HunanChina School of Minerals Processing and Bioengineering Central South UniversityChangsha 4003HunanChina

Precision engineering of catalytic sites to guide more favorable pathways for li_(2)O_(2) nucleation and decom-position represents an enticing kinetic strategy for mitigating overpotential,enhancing discharge capac-ity,and improving recycling stability of li-O_(2) *** this work,we employ metal-organic frameworks(MOFs)derivation and ion substitution strategies to construct atomically dispersed Mn-N_(4) moieties on hierarchical porous nitrogen-doped carbon(Mn SAs-NC)with the aim of reducing the over-potential and improving the cycling stability of li-O_(2) *** porous structure provides more chan-nels for mass transfer and exposes more highly active sites for electrocatalytic reactions,thus promoting the formation and decomposition of li_(2)O_(2).The li-O_(2) batteries with Mn SAs-NC cathode achieve lower overpotential,higher specific capacity(14290 mA h g^(-1) at 100 mAg^(-1)),and superior cycle stability(>100 cycles at 200 mA g^(-1))compared with the Mn NPs-NC and *** functional theory(DFT)cal-culations reveal that the construction of Mn-N_(4) moiety tunes the charge distribution of the pyridinic N-rich vacancy and balances the affinity of the intermediates(liO_(2) and li_(2)O_(2)).The initial nucleation of li_(2)O_(2) on Mn SAs-NC favors the O_(2)-→liO_(2)→li_(2)O_(2) surface-adsorption pathway,which mitigates the overpoten-tials of the oxygen reduction(ORR)and oxygen evolution reaction(OER).As a result,Mn SAs-NC with Mn-N_(4) moiety effectively facilitates the li_(2)O_(2) nucleation and enables its reversible *** work establishes a methodology for constructing carbon-based electrocatalysts with high activity and selectivity for li-O_(2)batteries.

关键词： Single-atom Mn MOFs-oriented architecture Rechargeable li-O_(2)battery N-doped carbon Density functional theory calculation

An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

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Science China Chemistry 2024年第9期67卷 2998-3003页

作者： Qi liu Xue-Dong li liang Cheng li liu Beijing National Laboratory for Molecular Sciences (BNLMS) CAS Key Laboratory of Molecular Recognition and Function CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements, which provides efficient methods for the preparation of axially chiral compounds. However, developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination process. In this work, we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent enantioselectivity. In addition, the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis acid. This methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%) and excellent central-to-axial chirality conversion(up to 99% conversion percentage). This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

关键词： brønsted acid catalysis desymmetrization phosphoric acid axially chiral biaryls central-to-axial conversion

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Polydatin ameliorates hepatic ischemia-reperfusion injury by modulating macrophage polarization

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 25-34页

作者： Hai-li Bao Chuan-Zhi Chen Chang-Zhen Ren Ke-Yan Sun Hao liu Shao-Hua Song Zhi-Ren fu Department of Organ Transplantation Shanghai Changzheng HospitalNavy Military Medical UniversityShanghai 200003China Department of Surgical Oncology the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China Department of Cardiology Shanghai Changzheng HospitalNaval Military Medical UniversityShanghai 200003China Department of General Surgery Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China

Background:Polydatin,a glucoside of resveratrol,has shown protective effects against various ***,little is known about its effect on hepatic ischemia-reperfusion(I/R)*** study aimed to elucidate whether polydatin protects liver against I/R-induced injury and to explore the underlying ***:After gavage feeding polydatin once daily for a week,mice underwent a partial hepatic I/R *** alanine aminotransferase(ALT)/aspartate aminotransferase(AST),hematoxylin-eosin(H&E)and TdT-mediated dUTP nick-end labeling(TUNEL)staining were used to evaluate liver *** severity related to the inflammatory response and reactive oxygen species(ROS)production was also ***,immunofluorescence and Western blotting were used to detect macrophage polarization and the NF-κB signaling pathway in ***:Compared with the I/R group,polydatin pretreatment significantly attenuated I/R-induced liver damage and *** oxidative stress marker(dihydroethidium fluorescence,malondialdehyde,superoxide dismutase and glutathione peroxidase)and I/R related inflammatory cytokines(interleukin1β,interleukin-10 and tumor necrosis factor-α)were significantly suppressed after polydatin *** addition,the result of immunofluorescence indicated that polydatin reduced the polarization of macrophages toward M1 macrophages both in vivo and in *** blotting showed that polydatin inhibited the pro-inflammatory function of RAW264.7 via down-regulating the NF-κB signaling ***:Polydatin protects the liver from I/R injury by remodeling macrophage polarization via NFκB signaling.

关键词： Hepatic ischemia-reperfusion injury Polydatin Macrophage Polarization Inflammation

A typhoon-induced storm surge numerical model with GPU acceleration based on an unstructured spherical centroidal Voronoi tessellation grid

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Acta Oceanologica Sinica 2024年第3期43卷 40-47页

作者： Yuanyong Gao fujiang Yu Cifu fu Jianxi Dong Qiuxing liu National Marine Environmental Forecasting Center Beijing 100081China Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesBeijing 100081China

Storm surge is often the marine disaster that poses the greatest threat to life and property in coastal *** and timely issuance of storm surge warnings to take appropriate countermeasures is an important means to reduce storm surge-related *** surge numerical models are important for storm surge *** further improve the performance of the storm surge forecast models,we developed a numerical storm surge forecast model based on an unstructured spherical centroidal Voronoi tessellation(SCVT)*** model is based on shallow water equations in vector-invariant form,and is discretized by Arakawa C *** SCVT grid can not only better describe the coastline information but also avoid rigid transitions,and it has a better global consistency by generating high-resolution grids in the key areas through transition *** addition,the simulation speed of the model is accelerated by using the openACC-based GPU acceleration technology to meet the timeliness requirements of operational ensemble *** only takes 37 s to simulate a day in the coastal waters of *** newly developed storm surge model was applied to simulate typhoon-induced storm surges in the coastal waters of *** hindcast experiments on the selected representative typhoon-induced storm surge processes indicate that the model can reasonably simulate the distribution characteristics of storm *** simulated maximum storm surges and their occurrence times are consistent with the observed data at the representative tide gauge stations,and the mean absolute errors are 3.5 cm and 0.6 h respectively,showing high accuracy and application prospects.

关键词： typhoon-induced storm surge numerical model GPU acceleration unstructured grid spherical centroidal Voronoi tessellation(SCVT)