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Enhanced Hoek-Brown(H-B)criterion for rocks exposed to chemical corrosion

International Journal of mining Science and Technology 2024年第5期34卷 609-630页

作者： Hao Li Leo Pel Zhenjiang you David Smeulders Department of mechanical Engineering Eindhoven University of TechnologyEindhoven 5600 MBthe Netherlands Department of Applied Physics Eindhoven University of TechnologyEindhoven 5600 MBthe Netherlands Center for Sustainable Energy and Resources School of EngineeringEdith Cowan UniversityJoondalupWA 6027Australia School of Chemical Engineering The University of QueenslandBrisbaneQLD 4072Australia Gas and Energy Transition Research Centre The University of QueenslandBrisbaneQLD 4072Australia

Underground constructions often encounter water environments,where water–rock interaction can increase porosity,thereby weakening engineering ***,the failure criterion for chemically corroded rocks becomes essential in the stability analysis and design of such *** study enhances the applicability of the Hoek-Brown(H-B)criterion for engineering structures operating in chemically corrosive conditions by introducing a kinetic porosity-dependent instantaneous mi(KPIm).A multiscale experimental investigation,including nuclear magnetic resonance(NmR),X-ray diffraction(XRD),scanning electron microscopy(SEm),pH and ion chromatography analysis,and triaxial compression tests,is employed to quantify pore structural changes and their linkage with the strength responses of limestone under coupled chemical-mechanical(C-m)*** employing ion chromatography and NmR analysis,along with incorporating the principles of free-face dissolution theory accounting for both congruent and incongruent dissolution,a kinetic chemical corrosion model is *** model aims to calculate the kinetic porosity alterations within rocks exposed to varying H+concentrations and ***,utilizing the generalized mixture rule(GmR),the kinetic porositydependent mi is *** of the KPIm-enhanced H-B criterion using compression test data from 5 types of rocks demonstrated a high level of consistency between the criterion and the experimental results,with a coefficient of determination greater than 0.96,a mean absolute percentage error less than 4.84%,and a root-mean-square deviation less than 5.95 ***,the physical significance of the porosity-dependent instantaneous mi is clarified:it serves as an indicator of a rock’s capacity to leverage the confining pressure effect.

关键词： Hoek-Brown(H-B)criterion Instantaneous mi Kinetic porosity-dependency Chemical corrosion Compressive strength

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Accelerated Primal-Dual Projection Neurodynamic Approach With Time Scaling for Linear and Set Constrained Convex Optimization Problems

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1485-1498页

作者： you Zhao Xing He mingliang Zhou Tingwen Huang Chongqing Key Laboratory of Nonlinear Circuits and Intelligent Information Processing College of Electronic and Information EngineeringSouthwest UniversityChongqing 400715China School of Computer Science Chongqing UniversityChongqing 400044China Department of mathematics Texas A&M University at QatarDoha 23874Qatar IEEE

The Nesterov accelerated dynamical approach serves as an essential tool for addressing convex optimization problems with accelerated convergence *** previous studies in this field have primarily concentrated on unconstrained smooth con-vex optimization *** this paper,on the basis of primal-dual dynamical approach,Nesterov accelerated dynamical approach,projection operator and directional gradient,we present two accelerated primal-dual projection neurodynamic approaches with time scaling to address convex optimization problems with smooth and nonsmooth objective functions subject to linear and set constraints,which consist of a second-order ODE(ordinary differential equation)or differential conclusion system for the primal variables and a first-order ODE for the dual *** satisfying specific conditions for time scaling,we demonstrate that the proposed approaches have a faster conver-gence *** only requires assuming convexity of the objective *** validate the effectiveness of our proposed two accel-erated primal-dual projection neurodynamic approaches through numerical experiments.

关键词： Accelerated projection neurodynamic approach lin-ear and set constraints projection operators smooth and nonsmooth convex optimization time scaling.

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A Quick Calculation method for Radiation Pattern of Submillimeter Telescope with Deformation and Displacement

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Research in Astronomy and Astrophysics 2024年第3期24卷 249-265页

作者： Jia you Yi-Wei Yao Zheng Wang School of Automation Southeast UniversityNanjing 210096China

Radiation pattern captures the electromagnetic performance of reflector antennas,which is significantly affected by the deformation of the primary reflector due to gravity and the displacement of the secondary *** the design process of large reflector antennas,a substantial amount of time is often dedicated to iteratively adjusting structural parameters and validating electromagnetic *** improve the efficiency of the design process,we first propose an approximate calculation method of optical path difference(OPD)for the deformation of the primary reflector under gravity and the displacement of the secondary *** an OPD fitting function based on the modified Zernike polynomials is proposed to capture the phase difference of radiation over the aperture plane,based on which the radiation pattern will be obtained quickly by the aperture field integration *** experiments demonstrate the effectiveness of the proposed quick calculation method for analyzing the radiation pattern of a 10.4 m submillimeter telescope antenna at its highest operating frequency of 856 *** comparison with the numerical simulation method based on GRASP(which is an antenna electromagnetic analysis tool combining physical optics(PO)and physical theory of diffraction(PTD)),the quick calculation method reduces the time for radiation pattern analysis from more than one hour to less than two ***,the quick calculation method exhibits excellent accuracy for the figure of merit(FOm)of the radiation ***,the proposed quick calculation method can obtain the radiation pattern with high speed and *** to the time-consuming numerical simulation method(PO and PTD),it can be employed for quick analysis of the radiation pattern for the lateral displacement of the secondary reflector and the deformation of the primary reflector under gravity in the design process of a reflector antenna.

关键词： instrumentation high angular resolution-methods data analysis-methods analytical

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High-Efficiency Dynamic Terahertz Deflector Utilizing a mechanically Tunable metasurface

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Research 2024年第3期2023卷 585-594页

作者： Zhenci Sun Chao Liang Chen Chen Xiayu Wang Enze Zhou Xiaomeng Bian Yuanmu Yang Rui you Xiaoguang Zhao Jiahao Zhao Zheng you Department of Precision Instrument Tsinghua UniversityBeijing 100084China State Key Laboratory of Precision measurement Technology and Instruments Tsinghua UniversityBeijing 100084China Beijing Advanced Innovation Center for Integrated Circuits Beijing 100084China School of Instrument Science and Opto-Electronic Engineering Beijing Information Science and Technology UniversityBeijing 100016China.

Terahertz (THz) wave manipulation, especially the beam deflection, plays an essential role in various applications, such as next-generation communication, space exploration, and high-resolution imaging. Current THz optical components and devices are hampered by their large bulk sizes and passive responses, limiting the development of high-performance, miniaturized THz microsystems. Tunable metasurfaces offer a powerful dynamic optical platform for controlling the propagation of electromagnetic waves. In this article, we presented a mechanically tunable metasurface (mTm), which can achieve terahertz beam deflection and vary the intensity of the anomalous reflected terahertz wave by changing the air gap between the metallic resonator (mR) array with phase discontinuities and Au ground plane. The absence of lossy spacer materials substantially enhances deflection efficiency. The device was fabricated by a combination of the surface and bulk-micromachining processes. The THz beam steering capability was characterized using terahertz time domain spectroscopy. When the air gap is 50 μm, the maximum deflection coefficient reaches 0.60 at 0.61 THz with a deflection angle of ~44.5°, consistent with theoretical predictions. We further established an electrically tunable miniaturized THz device for dynamic beam steering by introducing a micro voice coil motor to control the air gap continuously. It is shown that our designed mTm demonstrates a high modulation depth of deflection coefficient (~ 62.5%) in the target steered angle at the operating frequency. Our results showcase the potential of the proposed mTm as a platform for high-efficiency THz beam manipulation.

关键词： tunable Efficiency resonator

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Copper-Free Resin-Based Braking materials:A New Approach for Substituting Copper with Fly-Ash Cenospheres in Composites

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Chinese Journal of mechanical Engineering 2024年第2期37卷 401-412页

作者： Kaikui Zheng youxi Lin Shanmin you Zhiying Ren Jianmeng Huang School of mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China National United Engineering Laboratory for Advanced Bearing Tribology Henan University of Science and TechnologyLuoyang 471023China

Copper particles emitted from braking have become a significant source of environmental ***,copper plays a crucial role in resin-based braking *** high-performance braking materials without copper has become a significant *** this paper,the resin-based braking materials were filled with flyash cenospheres to develop copper-free braking *** effects of fly-ash cenospheres on the physical properties,mechanical and friction and wear properties of braking materials were ***,the wear mechanism of copper-free resin-based braking materials filled with fly-ash cenospheres was *** results indicate that the inclusion of fly-ash cenospheres in the braking materials improved their thermal stability,hardness and impact strength,reduced their density,effectively increased the friction coefficient at medium and high temperatures,and enhanced the heat-fade resistance of the braking *** inclusion of fly-ash cenospheres contributed to the formation of surface friction film during the friction process of the braking materials,and facilitated the transition of form from abrasive wear to adhesive *** 100-350℃,the friction coefficient of the optimal formulation is in the range of 0.57-0.61,and the wear rate is in the range(0.29-0.65)×10^(-7) cm^(3)·N^(-1)·m^(-1),demonstrating excellent resistance to heat-fade and stability in friction *** research proposes the use of fly-ash cenospheres as a substitute for environmentally harmful and expensive copper in brake materials,which not only improves the performance of braking materials but also reduces their costs.

关键词： Fly-ash cenospheres Braking materials Friction and wear Heat-fade resistance Wear form

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Effects of low molecular weight polysaccharide from Sargassum thunbergii against palmitic acid-induced intracellular lipid accumulation in 3T3-L1 adipocyte and HepG2 cells

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Food Science and Human Wellness 2024年第4期13卷 2244-2252页

作者： Hyo-Geun Lee D.P.Nagahawatta m.J.m.S.Kurera Kyung-mo Song Yun-Sang Choi you-Jin Jeon min-Cheol Kang Department of marine Life Sciences Jeju National UniversityJeju 63243Republic of Korea Department of Biotechnology Faculty of Agriculture and Plantation ManagementWayamba University of Sri LankaMakanduraGonawila(NWP)60170Sri Lanka Research Group of Food Processing Korea Food Research Institute245Wanju 55365Republic of Korea

Low molecular weight polysaccharides can be isolated from Sargassum thunbergii(LmPST)and in vitro experiments were conducted to evaluate the inhibitory effects on *** natures of LmPST were attained from *** and appraised their LmPST on palmitic acid(PA)induced lipid accretion in Hep G2,and 3T3-L1 *** treatment lessened lipid deposition and intracellular free fatty acid and triglyceride intensities in PA-treated above mentioned *** mechanistic study publicized that LmPST2 significantly suppressed adipogenesis and stimulated the PA-treated 3T3-L1 cells occupied in the lipolysis ***,in PA-treated Hep G2 cells,the free fatty acid oxidation was significantly increased by *** these constructive properties of LmPST2 from ***,is a potential candidate for diminishing the intracellular lipids,and for a therapeutic agent in those conditions.

关键词： Sargassum thunbergii Low molecular weight polysaccharide Lipid accumulation Obesity Liver steatosis

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The Adjustment Analysis method of the Active Surface Antenna Based on Convolutional Neural Network

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Research in Astronomy and Astrophysics 2024年第6期24卷 294-306页

作者： you Ban Shang Shi Na Wang Qian Xu Shufei Feng School of mechanical Engineering Xinjiang UniversityUrumqi 830017China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China School of mechanical Engineering Dongguan University of TechnologyDongguan 523808China

Active surface technique is one of the key technologies to ensure the reflector accuracy of the millimeter/submillimeter wave large reflector *** antenna is complex,large-scale,and high-precision equipment,and its active surfaces are affected by various factors that are difficult to comprehensively deal *** this paper,based on the advantage of the deep learning method that can be improved through data learning,we propose the active adjustment value analysis method of large reflector antenna based on deep *** method constructs a neural network model for antenna active adjustment analysis in view of the fact that a large reflector antenna consists of multiple panels spliced *** on the constraint that a single actuator has to support multiple panels(usually 4),an autonomously learned neural network emphasis layer module is designed to enhance the adaptability of the active adjustment neural network *** classical 8-meter antenna is used as a case study,the actuators have a mean adjustment error of 0.00252 mm,and the corresponding antenna surface error is0.00523 *** active adjustment result shows the effectiveness of the method in this paper.

关键词： techniques:radar astronomy telescopes methods:analytical methods:numerical

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Effect of mn Addition and Heat Treatment on the Corrosion Behaviour of mg-Ag-mn Alloy

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Acta metallurgica Sinica(English Letters) 2024年第4期37卷 665-677页

作者： you Lv Yupeng Zhang Xi Liu Zehua Dong Xiaorong Zhou Xinxin Zhang Key Laboratory of material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China Hubei Engineering Research Centre for Biomaterials and medical Protective materials Huazhong University of Science and TechnologyWuhan430074China Corrosion and Protection Centre Department of MaterialsThe University of ManchesterManchesterM139PLUK

The high corrosion sensitivity and the potential bio-toxicity of mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, mn is added into the mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of mg-Ag-mn alloys is investigated with the underlying microstructural factors examined. The mg-Ag alloy with 2 wt% mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of mn results in α-mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.

关键词： mg-Ag alloy mn addition Post-casting heat treatment Cathodic activity Corrosion mechanism

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An interfacial robust and entire self-healing ionogel-elastomer hybrid for elastic electronics enables discretionary assembly and reconfiguration

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Science China Chemistry 2024年第4期67卷 1316-1323页

作者： Lei Yang Lijie Sun Hongfei Huang Rasoul Esmaeely Neisiany Zhengwei you State Key Laboratory for modification of Chemical Fibers and Polymer materials Institute of Functional MaterialsCollege of Materials Science and EngineeringDonghua UniversityResearch Base of Textile Materials for Flexible Electronics and Biomedical Applications(China Textile Engineering Society)Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative MedicineShanghai 201620China Department of Polymer Engineering Hakim Sabzevari UniversitySabzevar ***Iran Biotechnology Centre Silesian University of TechnologyGliwice 44-100Poland

Inspired by the multi-layer architecture of mammal skins,interfacial robust,stretchable,and entirely healable gel-elastomer hybrids hold great potential in diverse fields including biomedical devices,wearable electrical devices,and soft ***,existing gel-elastomer hybrids have numerous limitations including low interfacial bonding toughness,complex and time-consuming preparation process,unhealable,and ***,we propose a simple and general chemical strategy through the interfacial dynamic bonding between gel and elastomer to simultaneously address the abovementioned *** covalent bonds readily and repeatably covalent bonding ionogel and elastomer(interfacial toughness:390 J m^(-2)),endowed the hybrids with entire self-healing features like skin and enabled discretionary assembly and ***,this strategy resolved the troublesome contradiction between interfacial stability and *** advantage of the aforementioned features,we readily constructed a multi-module,self-healing,self-powered,and realtime monitoring of personal status integrated elastic electronics,which could simply reconfigure the output signal of elastic electronics into an input signal of the devices-braille keyboard.

关键词： ionogel elastomer interface bonding self-healing dynamic covalent bond

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Dzyaloshinskii–moriya interaction and field-free sub-10 nm topological magnetism in Fe/bismuth oxychalcogenides heterostructures

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Chinese Physics B 2024年第9期33卷 200-206页

作者： Yaoyuan Wang Long you Kai Chang Hongxin Yang School of Integrated Circuits Huazhong University of Science and TechnologyWuhan 430074China Center for Quantum matter School of PhysicsZhejiang UniversityHangzhou 310058China Shenzhen Huazhong University of Science and Technology Research Institute Shenzhen 518000China

Topological magnetism with strong robustness,nanoscale dimensions and ultralow driving current density(106 A/m^(2))is promising for applications in information sensing,storage,and processing,and thus sparking widespread research *** candidate material systems with nanoscale size and easily tunable properties is a key for realizing practical topological magnetism-based spintronic ***,we propose a class of ultrathin heterostructures,Fe/Bi_(2)O_(2)X(X=S,Se,Te)by deposing metal Fe on quasi-two-dimensional(2D)bismuth oxychalcogenides Bi_(2)O_(2)X(X=S,Se,Te)with excellent ferroelectric/ferroelastic *** Dzyaloshinskii–moriya interaction(DmI)and topological magnetism can be *** atomistic spin dynamics simulations demonstrate that field-free vortex–antivortex loops and sub-10 nm skyrmions exist in Fe/Bi_(2)O_(2)S and Fe/Bi_(2)O_(2)Se interfaces,*** results provide a possible strategy to tailor topological magnetism in ultrathin magnets/2D materials interfaces,which is extremely vital for spintronics applications.

关键词： Dzyaloshinskii–moriya interaction field-free topological magnetism

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