This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resis...This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resistance of copper formate compared to traditional copper nanoparticles(CuNPs)and its ability to generate CuNPs through thermal decomposition.Experimental results demonstrate that the sintering process benefits from releasing reductive gases during decomposition,improving joint quality with reduced porosity and enhanced mechanical strength at elevated temperatures.Molecular dynamics simulations further elucidate the sintering behavior of CuNPs,providing significant insights into pore collapse,atomic mobility,and neck formation.The findings indicate that increased temperatures enhance surface and bulk diffusion,facilitating robust particle connections.Overall,this work establishes the potential of copper formate for achieving reliable interconnects in semiconductor devices,paving the way for advancements in material formulations for direct copper–copper bonding.展开更多
It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range ...It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range of crystallographic directions of shock loading has not been revealed.In this work,we calculated the shock Hugoniot for aluminum and copper in different crystallographic directions([100],[110],[111],[112],[102],[114],[123],[134],[221]and[401])of shock compression using molecular dynamics(MD)simulations.The results showed a high pressure(>160 GPa for Cu and>40 GPa for Al)of the FCC-to-BCC transition.In copper,different characteristics of the phase transition are observed depending on the loading direction with the[100]compression direction being the weakest.The FCC-to-BCC transition for copper is in the range of 150–220 GPa,which is consistent with the existing experimental data.Due to the high transition pressure,the BCC phase transition in copper competes with melting.In aluminum,the FCC-to-BCC transition is observed for all studied directions at pressures between 40 and 50 GPa far beyond the melting.In all considered cases we observe the coexistence of HCP and BCC phases during the FCC-to-BCC transition,which is consistent with the experimental data and atomistic calculations;this HCP phase forms in the course of accompanying plastic deformation with dislocation activity in the parent FCC phase.The plasticity incipience is also anisotropic in bothmetals,which is due to the difference in the projections of stress on the slip plane for different orientations of the FCC crystal.MD modeling results demonstrate a strong dependence of the FCC-to-BCC transition on the crystallographic direction,in which the material is loaded in the copper crystals.However,MD simulations data can only be obtained for specific points in the stereographic direction space;therefore,for more comprehensive understanding of the phase transition process,a feed-forward neural network was trained using MD modeling data.The trained machine learning model allowed us to construct continuous stereographic maps of phase transitions as a function of stress in the shock-compressed state of metal.Due to appearance and growth of multiple centers of new phase,the FCC-to-BCC transition leads to formation of a polycrystalline structure from the parent single crystal.展开更多
The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loa...The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted： the smaller behaves stronger. The evolution pattern of defects （i.e., dislocation and stacking faults） is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression.展开更多
The antifouling of marine facilities placed below the waterline is a key constraint to the development of the marine economy.Currently,commercial Cu_(2)O-based antifouling coatings still have defects such as agglomera...The antifouling of marine facilities placed below the waterline is a key constraint to the development of the marine economy.Currently,commercial Cu_(2)O-based antifouling coatings still have defects such as agglomeration,oxidation,short duration and high dosage.For this reason,we developed for the first time a triple antifouling system consisting of Cu_(2)O@poly(NIPAM-co-DAm)(Cu_(2)O@PND)dynamic redox micro-gels triggered by copper ions and polydimethylsiloxane(PDMS).The catechol groups of PND nanogels can chelate Cu^(2+)and reduce it in situ to obtain Cu_(2)O@PND microgels,which guarantees the stable release of Cu^(+).Furthermore,Cu_(2)O remains stable and free from oxidation because of the electron transfer between PND and Cu^(2+).Finally,superior antifouling performance was achieved by combining the stable Cu^(+)re-leased from Cu_(2)O,in situ conversion of PND to hydrogel,and its oxidation to produce active substances and H_(2)O_(2),and PDMS coating with low surface energy.展开更多
The inhibitory mechanism of copper（Ⅱ） on the aggegation of amyloid β-peptide （Aβ） was investigated by molecular dynamics simulations. The binding mode ofcopper（Ⅱ） with Aβ is characterized by the imidazole n...The inhibitory mechanism of copper（Ⅱ） on the aggegation of amyloid β-peptide （Aβ） was investigated by molecular dynamics simulations. The binding mode ofcopper（Ⅱ） with Aβ is characterized by the imidazole nitrogen atom, Nπ, of the histidine residue H 13, acting as the anchoring site, and the backbone＇s deprotoned amide nitogen atoms as the main binding sites. Drove by the coordination bonds and their induced hydrogen bond net, the conformations of Aβ converted from β-sheet non-β-sheet conformations, which destabilized the aggregation of Aβ into fibrils.展开更多
The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat ca...The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.展开更多
The three-dimensional(3D)graphene-based materials have raised significant interest due to excellent catalytic performance and unique electronic properties,while the preparation of uniform and stable 3D graphene struct...The three-dimensional(3D)graphene-based materials have raised significant interest due to excellent catalytic performance and unique electronic properties,while the preparation of uniform and stable 3D graphene structures remains a challenge.In this paper,using molecular dynamics simulations,we found that the nanotwinned copper(nt-Cu)matrix with small twin spacing can induce the wave-shaped wrinkling and sawtooth-shaped buckling graphene structures under uniaxial compression.The nt-Cu matrix possesses a symmetrical lattice structure for the lattice rotation with the dislocation annihilation,resulting in the transition of sandwiched graphene from 2D to 3D structures with good uniformity.The newly formed twin boundaries(TBs)in the nt-Cu matrix improve the resistance of graphene against the out-of-plane deformation so that graphene can maintain a stable wrinkling or buckling morphology in a wide strain range.These 3D texturing structures show great flexibility and their micro parameters can be controlled by applying different compressive strains.Furthermore,we propose a simple sliding method for decoupling graphene from the nt-Cu matrix without any damage.This work provides a novel strategy to induce and transfer the uniform wrinkling and buckling of graphene,which may expand the application of graphene in energy storage and catalysts.展开更多
In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this researc...In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this research project is to present a methodology for the simulation of a capture and cooling system of the smelting off-gases from a Pierce Smith copper converter, using computational fluid dynamics. Through this methodology, it is possible to obtain a simulation model of the smelting off-gases behavior with an average error of 9.88%. Basically, it demonstrates that the simulated tendencies of the metallurgical off-gases on the cooling hood and chamber can be reliable to predict the thermo-fluid dynamic behavior of the off-gases inside the studied off-gases handling system.展开更多
The hot deformation behavior of electrolytic copper was investigated using a Gleeble-3500 thermal simulation testing machine at temperatures ranging from 500℃ to 800℃ and strain rates ranging from 0.01 s^(-1) to 10 ...The hot deformation behavior of electrolytic copper was investigated using a Gleeble-3500 thermal simulation testing machine at temperatures ranging from 500℃ to 800℃ and strain rates ranging from 0.01 s^(-1) to 10 s^(-1),under 70% deformation conditions.The true stress-true strain curves were analyzed and a constitutive equation was established at a strain of 0.5.Based on the dynamic material model proposed by Prasad,processing maps were developed under different strain conditions.Microstructure of compressed sample was observed by electron backscatter diffraction.The results reveal that the electrolytic copper demonstrates high sensitivity to deformation temperature and strain rate during high-temperature plastic deformation.The flow stress decreases gradually with raising the temperature and reducing the strain rate.According to the established processing map,the optimal processing conditions are determined as follows:deformation temperatures of 600-650℃ and strain rates of 5-10 s^(-1).Discontinuous dynamic recrystallization of electrolytic copper occurs during high-temperature plastic deformation,and the grains are significantly refined at low temperature and high strain rate conditions.展开更多
The effects of trace cerium(Ce)addition on the microstructural and textural evolution and the dynamic recrystallization(DRX)of the ultrahigh-purity copper(Cu)containing small amounts of sulfur(S)were investigated usin...The effects of trace cerium(Ce)addition on the microstructural and textural evolution and the dynamic recrystallization(DRX)of the ultrahigh-purity copper(Cu)containing small amounts of sulfur(S)were investigated using a Gleeble-1500 thermal simulation tester at 600℃.The results show that with increasing Ce content,the grain size of the Cu-S(S2)alloy gradually decreases and the grain boundary embrittlement induced by S impurities is considerably inhibited.The addition of Ce promotes the DRX process of the S2 alloy and changes its DRX mechanism from discontinuous to continuous and twinning-induced DRX mechanisms.The texture component and intensity of the S2 alloy vary with the increase of Ce content.The addition of 120×10^(-6) Ce(mass fraction)is favorable for the grain orientation randomization,which is attributed to the promoted DRX.展开更多
The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series...The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then,the galvanic cell model was established,and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.展开更多
Lix984N is intimately related to the dynamic characteristics of phase disengagement in copper solvent extraction because of its interfacial activity. With increasing Lix984N content, the phase disengagement time is pr...Lix984N is intimately related to the dynamic characteristics of phase disengagement in copper solvent extraction because of its interfacial activity. With increasing Lix984N content, the phase disengagement time is prolonged and the mechanism dominating phase disengagement process transfers from sedimentation to coalescence. The rate of droplet coalescence is faster than that of droplet sedimentation in the dense dispersion band when the volume fraction of Lix984N is less than 3.0%. The former almost equaled to the latter at Lix984N content of 3.0% and finally becomes lower than the latter when the volume fraction of Lix984N is more than 3.0%. The relationship between the adhesion force of two equal droplets and physical properties of fluids is deduced, which explains that the change of physical properties of organic phase with Lix984N content can make droplet coalescence more difficult and phase disengagement slower.展开更多
Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature dis...Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature distribution were discussed. The simulation results indicate that the system temperature distribution presents a roughly concentric shape, a steep temperature gradient is observed in diamond cutting tool, and the highest temperature is located in chip. Centrosymmetry parameter method was used to monitor defect structures. Dislocations and vacancies are the two principal types of defect structures. Residual defect structures impose a major change on the workpiece physical properties and machined surface quality. The defect structures in workpiece are temperature dependent. As the temperature increases, the dislocations are mainly mediated from the workpiece surface, while the others are dissociated into point defects. The relatively high cutting speed used in nanomachining results in less defect structures, beneficial to obtain highly machined surface quality.展开更多
The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to underst...The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to understand the complicated phenomena ofelectrolyte flow behavior in vertical counter electrodes in full-scale copper ER cell,the three-dimensional computational fluiddynamics(CFD)models with four different arrangements of electrolyte inlets,i.e.,single inlet(SI),central bottom inlets(CBI),topside interlaced inlets(TII),and bottom side interlaced inlets(BII),were established to simulate the flow behavior.Simulation resultshave revealed that the parallel injection devices help to improve the electrolyte velocity between electrodes,and while the relativerange of electrolyte velocity in CBI exceeds that of TII and BII,which is more than4times,indicating its severer unequal flowdistribution.Meanwhile,the average velocity of electrolyte in BII is4times larger than that of SI due to its higher turbulenceintensity.Generally,one of the efficient ways to supply fresh copper solution rapidly and uniformly into the inter-electrode space is toadapt the arrangement of BII.By utilizing such an arrangement,the electro-refining under high electrical current density is possible,and the productivity can be increased in sequence.展开更多
The wear properties of ultrafine-grained （UFG） Cu samples of different purities were investigated in comparison with the coarse-grained （CG） Cu. The UFG Cu samples, prepared by means of plastic deformation via qua...The wear properties of ultrafine-grained （UFG） Cu samples of different purities were investigated in comparison with the coarse-grained （CG） Cu. The UFG Cu samples, prepared by means of plastic deformation via quasi- static compression, exhibit an enhanced wear resistance relative to the CG Cu samples. For both the UFG and the CG Cu samples, wear volumes increase at higher purities. A steady state worn subsurface structure was formed in each sample after sliding for 60 rain, consisting of a heavily deformed nanostructured mixing layer （NML） on top of a continuous dynamic recrystallization （DRX） layer. A pronounced correlation is identified that wear volume increases monotonically with an increasing grain size of the DRX layer. The impurity level of the Cu samples has an obvious influence on the DRX grain sizes, which in turn determines the wear resistance of the Cu samples.展开更多
Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy...Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle measurements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu 7 S 4 . The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu 7 S 4 admirably, compared with Cu, which contributes to the stable super hydrophobic surface.展开更多
The influences of initial grain size(IGS)with 20μm and 50μm on the hot flow behavior and microstructural changes of pure copper were investigated using hot compression tests at a temperature range of 623–1073 K and...The influences of initial grain size(IGS)with 20μm and 50μm on the hot flow behavior and microstructural changes of pure copper were investigated using hot compression tests at a temperature range of 623–1073 K and strain rate range of 0.001–0.1 s^(-1).The effects of critical stress and corresponding critical strain were studied based on the internal and external processing parameters.The critical stress and strain decreased with increasing temperature and decreasing strain rate.The investigation results of the microstructure and true strain–stress diagrams showed that dynamic recovery,dynamic recrystallization(DRX),and twinning mechanisms were caused during the hot deformation of pure copper.Microstructure evolution indicated some DRXed fine-grain took place around grain boundary of hot deformed samples with IGS of 20μm whereas DRXed fine-grain took place in interior grains for samples with larger IGS.The results also showed that grain growth is also dependent on IGS as the grain growth rate for samples with the larger IGS is greater than the smaller IGS.The critical strain rate and the temperature were obtained at 0.01 s^(-1) and 973 K,respectively,for the sudden change in the grain growth rate.Also,twinning highly depended on IGS which almost did not happen in fine grain size while the volume fraction of twinning increased with increasing grain size.展开更多
We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while...We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.展开更多
Through molecular dynamics simulations,the mechanical behavior of nanoporous copper under impact loading was investigated with relative densities ranging from 77.91% to 98.36%,focusing on deformation mechanism,the sca...Through molecular dynamics simulations,the mechanical behavior of nanoporous copper under impact loading was investigated with relative densities ranging from 77.91% to 98.36%,focusing on deformation mechanism,the scaling laws and influence of ligament sizes.Results show that the classical Gibson-Ashby′s scaling laws should be modified for prediction of both the Young′s modulus and yield stress.A proportional relationship is established between cell wall thickness and yield stress,and new modified scaling equations are built for nanoporous copper with consideration on both relative mass density and size effects of ligaments.The size effect can be explained by larger surface area/volume ratio of samples with thinner ligament size and limited dislocation source activation due to narrow space between larger numbers of voids.展开更多
The multiphase flow in a Peirce-Smith copper converter is numerically explored in this work. Molten matte, molten slag and air are the phases considered. The transient partial differential equations that constitute th...The multiphase flow in a Peirce-Smith copper converter is numerically explored in this work. Molten matte, molten slag and air are the phases considered. The transient partial differential equations that constitute the mathematical model are discretized using a two-dimensional computational mesh. The Computational Fluid Dynamics technique is employed to numerically solve the discretized equations. The aim of the numerical analysis is to study the influence of the nozzle height on the phase distributions inside the converter. Three values of the nozzle heights are considered.展开更多
基金financially supported by the Shenzhen Science and Technology Project(GXWD20220818163456002)the Key-Area Research and Development Program of Guangdong Province(No.2022B0701180002)+1 种基金the Sauvage Laboratory for Smart Materials of Harbin Institute of Technology(Shenzhen)the Guangdong Province College Students Science and Technology Innovation Cultivation Special Project.
文摘This study investigates using an antioxidation copper particle-free paste,formulated with self-reducing copper formate,for Cu-Cu bonding in electronic packaging applications.The research highlights the oxidation resistance of copper formate compared to traditional copper nanoparticles(CuNPs)and its ability to generate CuNPs through thermal decomposition.Experimental results demonstrate that the sintering process benefits from releasing reductive gases during decomposition,improving joint quality with reduced porosity and enhanced mechanical strength at elevated temperatures.Molecular dynamics simulations further elucidate the sintering behavior of CuNPs,providing significant insights into pore collapse,atomic mobility,and neck formation.The findings indicate that increased temperatures enhance surface and bulk diffusion,facilitating robust particle connections.Overall,this work establishes the potential of copper formate for achieving reliable interconnects in semiconductor devices,paving the way for advancements in material formulations for direct copper–copper bonding.
基金founded by the Ministry of Science and Higher Education of the Russian Federation,State assignments for research,registration No.1024032600084-8-1.3.2Study of the grain growth and the formation of polycrystalline structure as a result of phase transition(Section 6)was founded by the Russian Science Foundation,Project No.24-71-00078+3 种基金https://rscf.ru/en/project/24-71-00078/(accessed on 01 December 2025).Study of the orientation dependence of the phase transition of aluminum in Section 3 was founded by the Russian Science Foundation,Project No.24-19-00684https://rscf.ru/en/project/24-19-00684/(accessed on 01 December 2025).
文摘It is well known that aluminum and copper exhibit structural phase transformations in quasi-static and dynamic measurements,including shock wave loading.However,the dependence of phase transformations in a wide range of crystallographic directions of shock loading has not been revealed.In this work,we calculated the shock Hugoniot for aluminum and copper in different crystallographic directions([100],[110],[111],[112],[102],[114],[123],[134],[221]and[401])of shock compression using molecular dynamics(MD)simulations.The results showed a high pressure(>160 GPa for Cu and>40 GPa for Al)of the FCC-to-BCC transition.In copper,different characteristics of the phase transition are observed depending on the loading direction with the[100]compression direction being the weakest.The FCC-to-BCC transition for copper is in the range of 150–220 GPa,which is consistent with the existing experimental data.Due to the high transition pressure,the BCC phase transition in copper competes with melting.In aluminum,the FCC-to-BCC transition is observed for all studied directions at pressures between 40 and 50 GPa far beyond the melting.In all considered cases we observe the coexistence of HCP and BCC phases during the FCC-to-BCC transition,which is consistent with the experimental data and atomistic calculations;this HCP phase forms in the course of accompanying plastic deformation with dislocation activity in the parent FCC phase.The plasticity incipience is also anisotropic in bothmetals,which is due to the difference in the projections of stress on the slip plane for different orientations of the FCC crystal.MD modeling results demonstrate a strong dependence of the FCC-to-BCC transition on the crystallographic direction,in which the material is loaded in the copper crystals.However,MD simulations data can only be obtained for specific points in the stereographic direction space;therefore,for more comprehensive understanding of the phase transition process,a feed-forward neural network was trained using MD modeling data.The trained machine learning model allowed us to construct continuous stereographic maps of phase transitions as a function of stress in the shock-compressed state of metal.Due to appearance and growth of multiple centers of new phase,the FCC-to-BCC transition leads to formation of a polycrystalline structure from the parent single crystal.
基金supported by the National Natural Science Foundation of China (Nos10425210 and 10832002)the National Basic Research Program of China (No2006CB601202)the National High Technology Research and Development Program of China (No2006AA03Z519)
文摘The stress-strain behavior and copper are studied by the molecular dynamics incipient yield surface of nanoporous single crystal （MD） method. The problem is modeled by a periodic unit cell subject to multi-axial loading. The loading induced defect evolution is explored. The incipient yield surfaces are found to be tension-compression asymmetric. For a given void volume fraction, apparent size effects in the yield surface are predicted： the smaller behaves stronger. The evolution pattern of defects （i.e., dislocation and stacking faults） is insensitive to the model size and void volume fraction. However, it is loading path dependent. Squared prismatic dislocation loops dominate the incipient yielding under hydrostatic tension while stacking-faults are the primary defects for hydrostatic compression and uniaxial tension/compression.
基金financially supported by the National Natural Science Foundation of China (No.52073311)the Guangdong Basic and Applied Basic Research Foundation (Nos.2020A1515011274 and 2021A1515012281).
文摘The antifouling of marine facilities placed below the waterline is a key constraint to the development of the marine economy.Currently,commercial Cu_(2)O-based antifouling coatings still have defects such as agglomeration,oxidation,short duration and high dosage.For this reason,we developed for the first time a triple antifouling system consisting of Cu_(2)O@poly(NIPAM-co-DAm)(Cu_(2)O@PND)dynamic redox micro-gels triggered by copper ions and polydimethylsiloxane(PDMS).The catechol groups of PND nanogels can chelate Cu^(2+)and reduce it in situ to obtain Cu_(2)O@PND microgels,which guarantees the stable release of Cu^(+).Furthermore,Cu_(2)O remains stable and free from oxidation because of the electron transfer between PND and Cu^(2+).Finally,superior antifouling performance was achieved by combining the stable Cu^(+)re-leased from Cu_(2)O,in situ conversion of PND to hydrogel,and its oxidation to produce active substances and H_(2)O_(2),and PDMS coating with low surface energy.
基金This work was supported by the National Natural Science Foundation of China(Nos.30470408 and 20637010).
文摘The inhibitory mechanism of copper（Ⅱ） on the aggegation of amyloid β-peptide （Aβ） was investigated by molecular dynamics simulations. The binding mode ofcopper（Ⅱ） with Aβ is characterized by the imidazole nitrogen atom, Nπ, of the histidine residue H 13, acting as the anchoring site, and the backbone＇s deprotoned amide nitogen atoms as the main binding sites. Drove by the coordination bonds and their induced hydrogen bond net, the conformations of Aβ converted from β-sheet non-β-sheet conformations, which destabilized the aggregation of Aβ into fibrils.
文摘The melting and freezing processes of CUN （N =180, 256, 360, 408, 500, 628 and 736） nanoclnsters are simulated by using micro-canonical molecular dynamics simulation technique, The potential energies and the heat capacities as a function of temperature are obtained. The results reveal that the melting and freezing points increase almost linearly with the atom number in the cluster increasing. All copper nanoclusters have negative heat capacity around the melting and freezing points, and hysteresis effect in the melting/freezing transition is derived in CUN nanoclusters for the first time.
基金Australia Research Council Discovery Project(DP170103092)National Natural Science Foundation of China(NSFC51701030).
文摘The three-dimensional(3D)graphene-based materials have raised significant interest due to excellent catalytic performance and unique electronic properties,while the preparation of uniform and stable 3D graphene structures remains a challenge.In this paper,using molecular dynamics simulations,we found that the nanotwinned copper(nt-Cu)matrix with small twin spacing can induce the wave-shaped wrinkling and sawtooth-shaped buckling graphene structures under uniaxial compression.The nt-Cu matrix possesses a symmetrical lattice structure for the lattice rotation with the dislocation annihilation,resulting in the transition of sandwiched graphene from 2D to 3D structures with good uniformity.The newly formed twin boundaries(TBs)in the nt-Cu matrix improve the resistance of graphene against the out-of-plane deformation so that graphene can maintain a stable wrinkling or buckling morphology in a wide strain range.These 3D texturing structures show great flexibility and their micro parameters can be controlled by applying different compressive strains.Furthermore,we propose a simple sliding method for decoupling graphene from the nt-Cu matrix without any damage.This work provides a novel strategy to induce and transfer the uniform wrinkling and buckling of graphene,which may expand the application of graphene in energy storage and catalysts.
文摘In copper sulfide concentrates smelting, the off-gases from the Pierce Smith converter (PSC) furnace must be treated to prevent environmental impacts as they are highly corrosive and toxic. The purpose of this research project is to present a methodology for the simulation of a capture and cooling system of the smelting off-gases from a Pierce Smith copper converter, using computational fluid dynamics. Through this methodology, it is possible to obtain a simulation model of the smelting off-gases behavior with an average error of 9.88%. Basically, it demonstrates that the simulated tendencies of the metallurgical off-gases on the cooling hood and chamber can be reliable to predict the thermo-fluid dynamic behavior of the off-gases inside the studied off-gases handling system.
基金Gansu Province Higher Education Institutions Industrial Support Program Project(2022CYZC-19)Gansu Provincial Science and Technology Major Project(22ZD6GA008)。
文摘The hot deformation behavior of electrolytic copper was investigated using a Gleeble-3500 thermal simulation testing machine at temperatures ranging from 500℃ to 800℃ and strain rates ranging from 0.01 s^(-1) to 10 s^(-1),under 70% deformation conditions.The true stress-true strain curves were analyzed and a constitutive equation was established at a strain of 0.5.Based on the dynamic material model proposed by Prasad,processing maps were developed under different strain conditions.Microstructure of compressed sample was observed by electron backscatter diffraction.The results reveal that the electrolytic copper demonstrates high sensitivity to deformation temperature and strain rate during high-temperature plastic deformation.The flow stress decreases gradually with raising the temperature and reducing the strain rate.According to the established processing map,the optimal processing conditions are determined as follows:deformation temperatures of 600-650℃ and strain rates of 5-10 s^(-1).Discontinuous dynamic recrystallization of electrolytic copper occurs during high-temperature plastic deformation,and the grains are significantly refined at low temperature and high strain rate conditions.
基金financially supported by the National Natural Science Foundation of China(Nos.52071133,U21A2051)the Henan Province Science and Technology Tackling Key Problems Project,China(No.222102230001)+2 种基金the Zhongyuan Scholar Workstation Funded Project,China(No.224400510025)the Henan Key Research and Development Project,China(No.221111230600)Luoyang Major Science and Technology Innovation Special Project,China(No.2201017A)。
文摘The effects of trace cerium(Ce)addition on the microstructural and textural evolution and the dynamic recrystallization(DRX)of the ultrahigh-purity copper(Cu)containing small amounts of sulfur(S)were investigated using a Gleeble-1500 thermal simulation tester at 600℃.The results show that with increasing Ce content,the grain size of the Cu-S(S2)alloy gradually decreases and the grain boundary embrittlement induced by S impurities is considerably inhibited.The addition of Ce promotes the DRX process of the S2 alloy and changes its DRX mechanism from discontinuous to continuous and twinning-induced DRX mechanisms.The texture component and intensity of the S2 alloy vary with the increase of Ce content.The addition of 120×10^(-6) Ce(mass fraction)is favorable for the grain orientation randomization,which is attributed to the promoted DRX.
基金Project(2006AA06Z127) supported by the National Hi-tech Research and Development Program of ChinaProjects(50674029, 50274024) supported by the National Natural Science Foundation of China+1 种基金Project(20060145015) supported by Doctoral Program Foundation of Ministry of Education of ChinaProject(20052030) supported by the Natural Science Foundation of Liaoning Province, China
文摘The dynamic corrosion process of bio-oxidation of copper-nickel sulfide from Karatungk in northern Xinjiang Province of China was studied. The polished wafer of the copper-nickel sulphide was used to carry on a series of oxidation corrosion experiment by Acidithiobacillus ferrooxidans. The changes of superficial corrosion appearance and the mineral dynamic corrosion process were discovered by microscope observation. Then,the galvanic cell model was established,and the bio-oxidation activation order of typical copper-nickel sulphide minerals was ascertained as pyrrhotite>pentlandite>chalocopyrite.
文摘Lix984N is intimately related to the dynamic characteristics of phase disengagement in copper solvent extraction because of its interfacial activity. With increasing Lix984N content, the phase disengagement time is prolonged and the mechanism dominating phase disengagement process transfers from sedimentation to coalescence. The rate of droplet coalescence is faster than that of droplet sedimentation in the dense dispersion band when the volume fraction of Lix984N is less than 3.0%. The former almost equaled to the latter at Lix984N content of 3.0% and finally becomes lower than the latter when the volume fraction of Lix984N is more than 3.0%. The relationship between the adhesion force of two equal droplets and physical properties of fluids is deduced, which explains that the change of physical properties of organic phase with Lix984N content can make droplet coalescence more difficult and phase disengagement slower.
基金Project (50925521) supported by the National Natural Science Fund for Distinguished Young Scholars of China
文摘Molecular dynamics （MD） simulations of monocrystalline copper （100） surface during nanomachining process were performed based on a new 3D simulation model. The material removal mechanism and system temperature distribution were discussed. The simulation results indicate that the system temperature distribution presents a roughly concentric shape, a steep temperature gradient is observed in diamond cutting tool, and the highest temperature is located in chip. Centrosymmetry parameter method was used to monitor defect structures. Dislocations and vacancies are the two principal types of defect structures. Residual defect structures impose a major change on the workpiece physical properties and machined surface quality. The defect structures in workpiece are temperature dependent. As the temperature increases, the dislocations are mainly mediated from the workpiece surface, while the others are dissociated into point defects. The relatively high cutting speed used in nanomachining results in less defect structures, beneficial to obtain highly machined surface quality.
基金Project(61321003)supported by the National Natural Science Foundation of China
文摘The arrangement of electrolyte inlet in the copper electro-refining(ER)cell has a great influence on the local flow field,which affects the distribution of electrical current density in consequence.In order to understand the complicated phenomena ofelectrolyte flow behavior in vertical counter electrodes in full-scale copper ER cell,the three-dimensional computational fluiddynamics(CFD)models with four different arrangements of electrolyte inlets,i.e.,single inlet(SI),central bottom inlets(CBI),topside interlaced inlets(TII),and bottom side interlaced inlets(BII),were established to simulate the flow behavior.Simulation resultshave revealed that the parallel injection devices help to improve the electrolyte velocity between electrodes,and while the relativerange of electrolyte velocity in CBI exceeds that of TII and BII,which is more than4times,indicating its severer unequal flowdistribution.Meanwhile,the average velocity of electrolyte in BII is4times larger than that of SI due to its higher turbulenceintensity.Generally,one of the efficient ways to supply fresh copper solution rapidly and uniformly into the inter-electrode space is toadapt the arrangement of BII.By utilizing such an arrangement,the electro-refining under high electrical current density is possible,and the productivity can be increased in sequence.
基金support of the MOST 973 Project (Grant No.2012CB932201)Inter-national S&T Cooperation Project of China (Grant No.2010DFB54010)+2 种基金the National Natural Science Foundation (No.51141008)the CAS International Cooperation Project (Grant No.GJHZ1033)the CAS-Croucher Funding Scheme for Joint Laboratories and the Danish-Chinese Centre for Nanometals (Grant No.50911130230)
文摘The wear properties of ultrafine-grained （UFG） Cu samples of different purities were investigated in comparison with the coarse-grained （CG） Cu. The UFG Cu samples, prepared by means of plastic deformation via quasi- static compression, exhibit an enhanced wear resistance relative to the CG Cu samples. For both the UFG and the CG Cu samples, wear volumes increase at higher purities. A steady state worn subsurface structure was formed in each sample after sliding for 60 rain, consisting of a heavily deformed nanostructured mixing layer （NML） on top of a continuous dynamic recrystallization （DRX） layer. A pronounced correlation is identified that wear volume increases monotonically with an increasing grain size of the DRX layer. The impurity level of the Cu samples has an obvious influence on the DRX grain sizes, which in turn determines the wear resistance of the Cu samples.
基金Supported by the Beijing Youth Fellowship Program and the Fundamental Research Funds for the Central Universities(2011YXL056)
文摘Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle measurements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu 7 S 4 . The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu 7 S 4 admirably, compared with Cu, which contributes to the stable super hydrophobic surface.
文摘The influences of initial grain size(IGS)with 20μm and 50μm on the hot flow behavior and microstructural changes of pure copper were investigated using hot compression tests at a temperature range of 623–1073 K and strain rate range of 0.001–0.1 s^(-1).The effects of critical stress and corresponding critical strain were studied based on the internal and external processing parameters.The critical stress and strain decreased with increasing temperature and decreasing strain rate.The investigation results of the microstructure and true strain–stress diagrams showed that dynamic recovery,dynamic recrystallization(DRX),and twinning mechanisms were caused during the hot deformation of pure copper.Microstructure evolution indicated some DRXed fine-grain took place around grain boundary of hot deformed samples with IGS of 20μm whereas DRXed fine-grain took place in interior grains for samples with larger IGS.The results also showed that grain growth is also dependent on IGS as the grain growth rate for samples with the larger IGS is greater than the smaller IGS.The critical strain rate and the temperature were obtained at 0.01 s^(-1) and 973 K,respectively,for the sudden change in the grain growth rate.Also,twinning highly depended on IGS which almost did not happen in fine grain size while the volume fraction of twinning increased with increasing grain size.
基金the National Key Research and Development Program on Nano Science and Technology of the Ministry of Science and Technology of China(No.2016YFA0200602 and No.2018YFA0208702)the National Natural Science Foundation of China(No.21573211 and No.21633007)the Anhui Initiative in Quantum Information Technologies(No.AHY090200)。
文摘We constructed two types of copper-doped metal-organic framework(MOF),i.e.,Cu@UiO-66-NH2 and Cu-UiO-66-NH2.In the former,Cu2+ions are impregnated in the pore space of the amine-functionalized,Zr-based UiO-66-NH2;while in the latter,Cu^2+ions are incorporated to form a bimetal-center MOF,with Zr^4+being partially replaced by Cu2+in the Zr-O oxo-clusters.Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cudoped MOFs relative to undoped one,but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2.Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs.These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system,further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.
基金supported by the National Natural Science Foundation of China(11472098)the Program for New Century Excellent Talents in University of China(NCET-13-0773)the Natural Science Foundation of Jiangsu Province of China(BK20171437)
文摘Through molecular dynamics simulations,the mechanical behavior of nanoporous copper under impact loading was investigated with relative densities ranging from 77.91% to 98.36%,focusing on deformation mechanism,the scaling laws and influence of ligament sizes.Results show that the classical Gibson-Ashby′s scaling laws should be modified for prediction of both the Young′s modulus and yield stress.A proportional relationship is established between cell wall thickness and yield stress,and new modified scaling equations are built for nanoporous copper with consideration on both relative mass density and size effects of ligaments.The size effect can be explained by larger surface area/volume ratio of samples with thinner ligament size and limited dislocation source activation due to narrow space between larger numbers of voids.
文摘The multiphase flow in a Peirce-Smith copper converter is numerically explored in this work. Molten matte, molten slag and air are the phases considered. The transient partial differential equations that constitute the mathematical model are discretized using a two-dimensional computational mesh. The Computational Fluid Dynamics technique is employed to numerically solve the discretized equations. The aim of the numerical analysis is to study the influence of the nozzle height on the phase distributions inside the converter. Three values of the nozzle heights are considered.
