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A whole process damage constitutive model for layered sandstone under uniaxial compression based on Logistic function

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Journal of Central South University 2024年第7期31卷 2411-2430页

作者： LIU dong-qiao GUO Yun-peng LING Kai LI Jie-yu State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China

Bedding structural planes significantly influence the mechanical properties and stability of engineering rock *** study conducts uniaxial compression tests on layered sandstone with various bedding angles(0°,15°,30°,45°,60°,75°and 90°)to explore the impact of bedding angle on the deformational mechanical response,failure mode,and damage evolution processes of *** develops a damage model based on the Logistic equation derived from the modulus’s degradation considering the combined effect of the sandstone bedding dip angle and *** model is employed to study the damage accumulation state and its evolution within the layered rock *** research also introduces a piecewise constitutive model that considers the initial compaction characteristics to simulate the whole deformation process of layered sandstone under uniaxial *** results revealed that as the bedding angle increases from 0°to 90°,the uniaxial compressive strength and elastic modulus of layered sandstone significantly decrease,slightly increase,and then decline *** corresponding failure modes transition from splitting tensile failure to slipping shear failure and back to splitting tensile *** indicated by the modulus’s degradation,the damage characteristics can be categorized into four stages:initial no damage,damage initiation,damage acceleration,and damage deceleration *** theoretical damage model based on the Logistic equation effectively simulates and predicts the entire damage evolution ***,the theoretical constitutive model curves closely align with the actual stress−strain curves of layered sandstone under uniaxial *** introduced constitutive model is concise,with fewer parameters,a straightforward parameter determination process,and a clear physical *** study offers valuable insights into the theory of layered rock mechanics and holds implications for ensuring the safety of rock engineering.

关键词： layered sandstone uniaxial compression damage evolution Logistic function constitutive model

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Enhanced thermoelectric performance enabled by compositing ZrO_(2)in n-type SiGe alloy with low thermal conductivity

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Rare Metals 2024年第3期43卷 1167-1176页

作者： Meng-Fei Wang Hua-Jun Lai Ji-Sheng liang Jun-liang Chen Wang-Yang Ding Qi Zhou Ying peng Cheng-Yan Liu Lei Miao Guangxi Key Laboratory for Relativity Astrophysics State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite StructuresSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China Guangxi Academy of Sciences Nanning530007China Key Laboratory of Information Material Engineering Research Center of Electronic Information Materials and DevicesGuilin University of Electronic TechnologyMinistry of EducationGuilin541004China Guangxi Key Laboratory of Precision Navigation Technology and Application School of Information and CommunicationGuilin University of Electronic TechnologyGuilin541004China

SiGe-based thermoelectric(TE)materials have gained increasing interests due to their low maintenance costs,environmental friendliness and long ***,the intrinsically high thermal conductivity of Si-based materials also results in poor TE *** this investigation,a zirconia(ZrO_(2))composite strategy was applied to an n-type SiGe alloy,tremendously elevating its TE *** mechanical alloying and spark plasma sintering(SPS)processes,the ZrO_(2)induced the formation of nanopores in the SiGe matrix via phosphorus ***,such increase in porosity enhanced the phonon scattering and dramatically suppressed lattice thermal conductivity,from 2.83 to 1.59 W·m^(-1)·K^(-1)at 873 ***,reduced phosphorus doping led to an increase in Seebeck coefficients and a relatively minor decrease in electrical conductivity,The power factor didn't deteriorate significantly,either,as its maximum of~3.43 mW·m^(-1-)K^(-2)was achieved at 873 K with(Si_(0.8)Ge_(0.2))_(0.097)P_(0.03)(ZrO_(2))_(0.003).In short,a peak figure of merit(ZT)of~1.27 at 873 K and an average ZT~0.7 from 323 to 873 K were *** study demonstrates that the electrical and thermal transportation of SiGe material can be synergistically tuned by compositing ZrO_(2),illustrating a novel strategy to optimize the TE properties of bulk materials.

关键词： Thermoelectric SiGe alloy ZrO2 composting P element adsorption nanopores

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Continuous gradient fusion class activation mapping: segmentation of laser-induced damage on large-aperture optics in dark-field images

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High Power Laser Science and Engineering 2024年第1期12卷 30-41页

作者： Yueyue Han Yingyan Huang Hangcheng dong Fengdong Chen Fa Zeng Zhitao peng Qihua Zhu Guodong Liu School of Instrumentation Science and Engineering Harbin Institute of TechnologyHarbinChina Research Center of Laser Fusion China Academy of Engineering PhysicsMianyangChina

Segmenting dark-field images of laser-induced damage on large-aperture optics in high-power laser facilities is challenged by complicated damage morphology, uneven illumination and stray light interference. Fully supervised semantic segmentation algorithms have achieved state-of-the-art performance but rely on a large number of pixel-level labels, which are time-consuming and labor-consuming to produce. LayerCAM, an advanced weakly supervised semantic segmentation algorithm, can generate pixel-accurate results using only image-level labels, but its scattered and partially underactivated class activation regions degrade segmentation performance. In this paper, we propose a weakly supervised semantic segmentation method, continuous gradient class activation mapping(CAM) and its nonlinear multiscale fusion(continuous gradient fusion CAM). The method redesigns backpropagating gradients and nonlinearly activates multiscale fused heatmaps to generate more fine-grained class activation maps with an appropriate activation degree for different damage site sizes. Experiments on our dataset show that the proposed method can achieve segmentation performance comparable to that of fully supervised algorithms.

关键词： class activation maps laser-induced damage semantic segmentation weakly supervised learning

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Constant charge method or constant potential method:Which is better for molecular modeling of electrical double layers?

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Journal of Energy Chemistry 2024年第7期94卷 54-60页

作者： liang Zeng Xi Tan Xiangyu Ji Shiqi Li Jinkai Zhang Jiaxing peng Sheng Bi Guang Feng State Key Laboratory of Coal Combustion Schoolof Energy and PowerEngineeringHuazhong Universityof Science and Technology(HUST)Wuhan 430074HubeiChina Sorbonne Universite CNRSPhysico-chimie des Electrolytes et Nanosystemes InterfaciauxPHENIXF-75005 ParisFrance

In molecular modeling of electrical double layers(EDLs),the constant charge method(CCM)is prized for its computational efficiency but cannot maintain electrode equipotentiality like the more resourceintensive constant potential method(CPM),potentially leading to *** certain scenarios,CCM can yield results identical to ***,there are no clear guidelines to determine when CCM is sufficient and when CPM is ***,we conduct a series of molecular simulations across various electrodes and electrolytes to present a comprehensive comparison between CCM and CPM under different charging *** reveal that CCM approximates CPM effectively in capturing equilibrium EDL and current-driven dynamics in open electrode systems featuring ionic liquids or regular concentration aqueous electrolytes,while CPM is indispensable in scenarios involving organic and highly concentrated aqueous electrolytes,nanoconfinement effects,and voltage-driven *** work helps to select appropriate methods for modeling EDL systems,prioritizing accuracy while considering computationalefficiency.

关键词： Electrochemical interface Molecular dynamics Electrode polarization modeling Nanoconfinement effect

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Multiscale microstructural consideration of enhanced shear strength in TiAl intermetallic/K4169 alloy composite joints prepared by vacuum brazing with(Ti,Zr)-Ni-based amorphous filler metal

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Journal of Materials Science & Technology 2024年第5期172卷 51-70页

作者： liangliang Zhang Honggang dong peng Li Baosheng Wu Yueting Ma Libing Huang Chao Li Jiachen Li School of Materials Science and Engineering Dalian University of TechnologyDalian 116024China

TiAl intermetallic could be used to replace Ni-based alloy in assemblies to generate excellent specific strength.A(Ti,Zr)-Ni-based amorphous filler metal Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)(at.%)was designed using a cluster-plus-glue-atom model to successfully vacuum braze K4169 and TiAl bimetallic *** various brazing temperatures and holding time,the quantitative relationships between lattice distortion,grain boundary,dislocation density,and hardness,elastic modulus,shear strength of the joints were ***,the fracture mechanism of the joints was *** brazed seam mainly consisted of solid diffusion reaction layers(ZonesⅠandⅢ)and filler metal residue zone(ZoneⅡ).When the brazing temperature increased to 1030℃,grain refinement occurred in the brazed ***Ⅰwas primarily composed of(Ni)ss[0-11]+TiNi[011]/(Cr,Fe,Ni)ss[0-11]/(Ti,Zr)Ni[0-1-1]+(Cr,Fe,Ni)ss[0-11].The(Ti,Zr)(Ni,Cu)[001]and(Ti,Zr)(Ni,Cu)[101]intermetallic compound-based solid solutions were formed in ZoneⅡ.And the lattice distortion of(Ti,Zr)(Ni,Cu)[101]and(Ti,Zr)(Ni,Cu)[001]was 32.05%and 14.82%,*** a result,the proportion of low angle grain boundaries(LAGBs)and deformed grains in ZoneⅡrose to 38.6%and 38.7%.In ZonesⅠandⅢ,the proportion of LAGBs reduced to 8%and 3.4%,*** the holding time increased,the long-range diffusion of Al in ZoneⅡcaused the(Ti,Zr)(Ni,Cu)[001]with cubic structure to transform into(Ti,Zr)(Ni,Cu,Al)[00-1]with hexagonal crystal system structure,where the lattice distortion was 4.42%and 10.49%for a and *** 1030℃/10 min,the average geometrically nec-essary dislocation densities(GNDs)in ZonesⅠ,ⅡandⅢwere 9.87×10^(14)m^(-2),8.55×10^(14)m^(-2)and 11.4×10^(14)m^(-2),***,the shear strength of joints reached 322 MPa due to the lattice distortion,dislocation strengthening and fine grain ***,the plastic and brittle hard phases were generated in ZoneⅡand displayed a mechanical interlocking structure tha

关键词： K4169/Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/TiAl composite joints Intermetallic compound-based solid solution Lattice distortion Elastic modulus

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Triboelectric‘electrostatic tweezers'for manipulating droplets on lubricated slippery surfaces prepared by femtosecond laser processing

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International Journal of Extreme Manufacturing 2024年第3期6卷 411-426页

作者： Jiale Yong Xinlei Li Youdi Hu Yubin peng Zilong Cheng Tianyu Xu Chaowei Wang dong Wu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision InstrumentationUniversity of Science and Technology of ChinaHefei 230027People’s Republic of China

The use of‘Electrostatic tweezers'is a promising tool for droplet manipulation,but it faces many limitations in manipulating droplets on superhydrophobic ***,we achieve noncontact and multifunctional droplet manipulation on Nepenthes-inspired lubricated slippery surfaces via triboelectric electrostatic tweezers(TETs).The TET manipulation of droplets on a slippery surface has many advantages over electrostatic droplet manipulation on a superhydrophobic *** electrostatic field induces the redistribution of the charges inside the neutral droplet,which causes the triboelectric charged rod to drive the droplet to move forward under the electrostatic *** or negatively charged droplets can also be driven by TET based on electrostatic attraction and *** enables us to manipulate droplets under diverse conditions,including anti-gravity climb,suspended droplets,corrosive liquids,low-surface-tension liquids(*** with a surface tension of 22.3 mN·m^(-1)),different droplet volumes(from 100 nl to 0.5 ml),passing through narrow slits,sliding over damaged areas,on various solid substrates,and even droplets in an enclosed *** droplet-related applications,such as motion guidance,motion switching,droplet-based microreactions,surface cleaning,surface defogging,liquid sorting,and cell labeling,can be easily achieved with TETs.

关键词： triboelectric electrostatic tweezer droplet manipulation slippery surface superhydrophobic surface femtosecond laser

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Mechanical properties and microstructure of Mg-treated and Catreated industrial H13 steel after quenching and tempering

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Journal of Iron and Steel Research International 2024年第8期31卷 1987-2001页

作者： Jun-ying Yue dong Hou De-yong Wang Tian-peng Qu Xiang-long Li Jun Tian School of Iron and Steel Soochow UniversitySuzhou 215021JiangsuChina

The effect of magnesium treatment and calcium treatment on the microstructure and mechanical properties of industrial H13 steel after quenching and tempering was *** impact toughness and tensile tests were mainly carried out,and the microstructure was observed by scanning electron microscopy,electron backscattered diffraction,and X-ray *** results show that magnesium treatment is still feasible in industrial *** is mainly manifested in the refinement of lath martensite and *** with calcium treatment,the prior austenite grains and carbides size of industrial H13 steel treated with magnesium decreased by 3.17μm after *** quenching and tempering,the carbides(especially V-rich carbides)in Mg treatment obviously spheroidized and distributed uniformly and increased in quantity *** lath martensite size is reduced from 2.45 to 2.31μ*** suggests that magnesium treatment was able to yield smaller grains and more evenly distributed ***,the impact toughness,yield strength,and ultimate tensile strength of industrial H13 steel with magnesium treatment increased by 28%,65.5 MPa and 123.7 MPa,*** increment of strength mainly comes from dislocation strengthening,grain refinement strengthening,and precipitation strengthening,among which precipitation strengthening accounts for the largest proportion.

关键词： Industrial H13 steel Mg treatment Heat treatment Carbide-Mechanical property

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Covalent triazine frameworks materials for photo-and electrocatalysis

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Nano Research 2024年第9期17卷 7830-7839页

作者： Aoji liang Wenbin Li Anbai Li Hui peng Guofu Ma Lei Zhu Ziqiang Lei Yuxi Xu Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education Key Laboratory of Polymer Materials of Gansu ProvinceCollege of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou 730070China School of Chemistry and Materials Science Hubei Key Laboratory of Quality Control of Characteristic Fruits and VegetablesHubei Engineering UniversityXiaogan 432000China School of Engineering Westlake UniversityHangzhou 310024China

Covalent triazine frameworks(CTFs)are a class of unique two-dimensional nitrogen-rich triazine framework with adjustable chemical and electronic structures,rich porosity,good stability and excellent semiconductivity,which enable great various applications in efficient gas/molecular adsorption and separation,energy storage and conversion,especially photo-and *** synthesis strategies strongly affect the morphology of CTFs and play an important role in their structure and *** this concept,we provide a comprehensive and systematic review of the synthesis methods such as ionothermal synthesis,phosphorus pentoxide catalytic method,polycondensation and ultra-strong acid catalyzed method,and applications of CTFs in photo-and *** we offer some insights into the future development progress of CTFs materials for catalytic applications.

关键词： covalent triazine frameworks synthetic strategy photocatalysis electrocatalysis

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Effect of electrolyte cation-mediated mechanism on electrocatalytic carbon dioxide reduction

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Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： Yuan dong Mutian Ma Zhenyang Jiao Sheng Han Likun Xiong Zhao Deng Yang peng Soochow Institute of Energy and Material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(CO_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of CO_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence CO_(2)RR by mechanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular mechanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： CO_(2)electrocatalytic reduction Cation effects Catalytic mechanisms Catalytic interfaces Electric double layer

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Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply

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Journal of Integrative Agriculture 2024年第3期23卷 1048-1060页

作者： peng Wang Lan Yang Xichao Sun Wenjun Shi Rui dong Yuanhua Wu Guohua Mi Key Laboratory of Tobacco Biology and Processing of Ministry of Agriculture and Rural Affairs Tobacco Research InstituteChineseAcademy of Agricultural SciencesQingdao 266101China Department of Plant Nutrition College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193China College of Resources Hunan Agricultural UniversityChangsha 410128China Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsTianjin 300191China

A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still ***,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial *** main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly *** addition,the average LR density of 2nd whorl crown root under mixed N was also *** with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further ***,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this ***,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this *** study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.

关键词： maize NO_(3)^(–)/NH_(4)^(+)ratio lateral root elongation N assimilation indole-3-acetic acid

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