The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In...The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.展开更多
In order to effectively predict the fracture of AA7075-T6 sheet, the forming limit curves of AA7075-T6 high-strength sheet were drawn according to Morciniak Kuczyski (M K) model and Lou Huh criterion, respectively. Th...In order to effectively predict the fracture of AA7075-T6 sheet, the forming limit curves of AA7075-T6 high-strength sheet were drawn according to Morciniak Kuczyski (M K) model and Lou Huh criterion, respectively. The errors between the predicted values of the two theoretical prediction models and experimental values were calculated by error analysis. The forming limit curves were verified by the punch stretch test to evaluate the prediction accuracy of M K model and Lou Huh criterion. The error analysis results show that the mean error of Lou Huh criterion with the optimal parameters for all tensile specimens is 25.04%, while the mean error of M K model for all tensile specimens is 74.24%. The prediction accuracy of Lou Huh criterion in predicting the fracture of AA7075-T6 sheet is higher. The punch stretch test results show that the forming limit curve drawn by Lou Huh criterion can effectively predict the fracture of AA7075-T6 sheet, but the prediction accuracy of M K model is relatively poor.展开更多
Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2...Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2 crystal surfaces on the catalytic activity of Cu O–CeO2 for the oxidation of CO is still unclear and should be further elucidated. In this study, we deposited 1 wt% Cu on mostly {100}-exposed CeO2 nanocubes(1 Cu Ce NC) and mostly {110}-exposed CeO2 nanorods(1 Cu Ce NR), respectively. Both 1 Cu Ce NC and 1 Cu Ce NR have been used as catalysts for the oxidation of CO and achieved 100% and 50% CO conversion at 130 ℃, respectively. The differences in the catalytic activity of 1 Cu Ce NC and 1 Cu Ce NR were analyzed using temperature-programmed reduction of H2 and temperature-programmed desorption of CO techniques. The results confirmed the excellent reducibility of the 1 Cu Ce NC catalyst, which was attributed to the weak interactions between Cu and the CeO2 support. Moreover, in situ diffuse reflectance infrared Fourier-transform spectroscopy studies indicated that the {100} planes of 1 Cu Ce NC facilitated the generation of active Cu(I) sites, which resulted in the formation of highly reactive Cu(I)-CO species during the oxidation of CO. Both the excellent redox properties and effective CO adsorption capacity of the 1 Cu Ce NC catalyst increased its catalytic reactivity.展开更多
TiBw/TC4composite was brazed to Ti60alloy successfully using TiZrNiCu amorphous filler alloy,and the interfacialmicrostructures and mechanical properties were characterized by SEM,EDX,XRD and universal tensile testing...TiBw/TC4composite was brazed to Ti60alloy successfully using TiZrNiCu amorphous filler alloy,and the interfacialmicrostructures and mechanical properties were characterized by SEM,EDX,XRD and universal tensile testing machine.The typicalinterfacial microstructure was TiBw/TC4composite/β-Ti+TiB whiskers/(Ti,Zr)2(Ni,Cu)intermetallic layer/β-Ti/Ti60alloy whenbeing brazed at940°C for10min.The interfacial microstructure evolution was influenced strongly by the diffusion and reactionbetween molten fillers and the substrates.Increasing brazing temperature decreased the thickness of brittle(Ti,Zr)2(Ni,Cu)intermetallic layer,which disappeared finally when the brazing temperature exceeded1020°C.Fracture analyses indicated thatcracks were initialized in the brittle intermetallic layer when(Ti,Zr)2(Ni,Cu)phase existed in the brazing seam.The maximumaverage shear strength of joints reached368.6MPa when brazing was conducted at1020°C.Further increasing brazing temperatureto1060°C,the shear strength was decreased due to the formation of coarse lamellar(α+β)-Ti structure.展开更多
In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibit...In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.展开更多
High-resolution transmission electron microscopy(TEM),X-ray diffractometer(XRD),and hardness test were used to study the evolution of long plate-shaped S'phase in the spray-formed fine-grained Al−Cu−Mg alloy durin...High-resolution transmission electron microscopy(TEM),X-ray diffractometer(XRD),and hardness test were used to study the evolution of long plate-shaped S'phase in the spray-formed fine-grained Al−Cu−Mg alloy during aging after rapid cold punching deformation.Results show that the long plate-shaped S'phase in the extruded Al−Cu−Mg alloy undergoes evident distortion,brittle failure,separation and redissolution,during rapid cold punching deformation,leading to the transformation of long plate-shaped S'phase into short rod or even redissolution and disappearance,causing the matrix to become a supersaturated solid solution.After the aging treatment,the reprecipitation of the phases occurs,and these aging phases are mainly long plate-shaped and granular.The incompletely dissolved S'phase acts as nucleation core,promoting uphill diffusion of the surrounding solute atoms.The S'phase gradually grows with increasing the aging time.The completely dissolved S'phase forms the incoherent equilibrium phase with the matrix to reduce its free energy.After rapid cold punching,the aging response of the deformed Al−Cu−Mg alloy is accelerated,and the hardness of the alloy is substantially increased.展开更多
The microstructure and mechanical properties of multi-layer multi-pass TIG welded joints of Al-Zn-Mg alloy plates were studied.The phase constituent and microstructure of different regions of the welded joints were ch...The microstructure and mechanical properties of multi-layer multi-pass TIG welded joints of Al-Zn-Mg alloy plates were studied.The phase constituent and microstructure of different regions of the welded joints were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),transmission electron microscopy(TEM)and energy disperse spectrum(EDS),while the mechanical properties were evaluated according to the impact test.A dispersively distributed spherical and needle-likeη(MgZn2)phase was obtained in the welding seam.The phase composition of the heat-affected zone(HAZ)wasα(Al)+η(MgZn2)+Al6Mn,and there were a large number of dispersively precipitated nanoscale particles.The welded joint zone had the highest impact toughness as compared with the other parts of the joint.The MgZn2 phase in the weld zone contributed to the improved toughness of the joint.Al2 MgCu phase in HAZ was proven to act as a crack source during fracture.展开更多
In order to better describe the phenomenon of biological invasion,this paper introduces a free boundary model of biological invasion.Firstly,the right free boundary is added to the equation with logistic terms.Secondl...In order to better describe the phenomenon of biological invasion,this paper introduces a free boundary model of biological invasion.Firstly,the right free boundary is added to the equation with logistic terms.Secondly,the existence and uniqueness of local solutions are proved by the Sobolev embedding theorem and the comparison principle.Finally,according to the relevant research data and contents of red fire ants,the diffusion area and nest number of red fire ants were simulated without external disturbance.This paper mainly simulates the early diffusion process of red fire ants.In the early diffusion stage,red fire ants grow slowly and then spread over a large area after reaching a certain number.展开更多
To clarify the transformation mechanism of secondary phase and the mechanism of intergranular corrosion in laser welding Ni-based alloy (Hastelloy C-276)/304 stainless steel with filler wire,the secondary phase was an...To clarify the transformation mechanism of secondary phase and the mechanism of intergranular corrosion in laser welding Ni-based alloy (Hastelloy C-276)/304 stainless steel with filler wire,the secondary phase was analyzed by electron probe micro-analysis (EPMA) and transmission electron microscopy (TEM).The evaluation of intergranular corrosion resistance of the welded joints was conducted by double-loop electrochemical potentiokinetic reactivation(DL-EPR) method,and at the same time the chemical compositions of the corrosion surface were analyzed by energy-dispersive spectrometry (EDS).The results show that p phase has complete coherence relationship withμphase,and the coherent relationship is described as[001]p//■and[430]p//[0001]μ.Theμphase is rapidly transformed from p phase,which is the inhomogeneous phase transformation.The transformation of secondary phase will increase the susceptibility to intergranular corrosion.Therefore,the transformation of secondary phase should be avoided in the welding process.展开更多
Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been construc...Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.展开更多
To investigate the effect of separate Al_(2)Ca and Mg_(2)Ca phases on the corrosion properties of Mg−Al−Ca−Mn alloys,OM,SEM,immersion and electrochemical tests were conducted on the as-cast and ECAP Al_(2)Ca-containin...To investigate the effect of separate Al_(2)Ca and Mg_(2)Ca phases on the corrosion properties of Mg−Al−Ca−Mn alloys,OM,SEM,immersion and electrochemical tests were conducted on the as-cast and ECAP Al_(2)Ca-containing(2Ca)and Mg_(2)Ca-containing(4Ca)alloys.At the beginning of corrosion,the two as-cast alloys are corroded slowly compared with ECAP alloys.With prolonging the corrosion time,the corrosion of ECAP alloys becomes slighter than that of as-cast alloys,which is mainly ascribed to the dispersion and refinement of the second phase in ECAP alloys.Moreover,the corrosion degree of 2Ca alloys is always slighter than that of 4Ca alloys,suggesting that Al_(2)Ca phase is more beneficial to the enhancement of corrosion resistance of Mg−Al−Ca−Mn based alloys than Mg_(2)Ca phase.Finally,based on the examinations of corrosion surface and electrochemical testing results,different corrosion mechanisms caused by the distributions and morphology of Al_(2)Ca and Mg_(2)Ca phases are discussed.展开更多
The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(...The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.展开更多
文摘The design and construction of heterojunction photocatalysts,which possess a staggered energy band structure and appropriate interfacial contact,is an effective way to achieve outstanding photocatalytic performance.In this study,2D/2D BiOBr/g‐C_(3)N_(4)heterojunctions were successfully obtained by a convenient in situ self‐assembly route.Under simulated sunlight irradiation,99%of RhB(10 mg·L–1,100 mL)was efficiently degraded by 1.5‐BiOBr/g‐C_(3)N_(4)within 30 min,which is better than the performance of both BiOBr and g‐C_(3)N_(4),and it has superior stability.In addition,the composite also exhibits enhanced photocatalytic activity for H2 production.The enhanced activity can be attributed to the intimate interface contact,the larger surface area,and the highly efficient separation of photoinduced electron–hole pairs.Based on the experimental results,a novel S‐scheme model was proposed to illuminate the transfer process of charge carriers.This study presents a simple way to develop novel step‐scheme photocatalysts for environmental and related applications.
基金Project (51775481) supported by the National Natural Science Foundation of ChinaProject (E2019203418) supported by the Natural Science Foundation of Hebei Province, ChinaProject (ZD2017078) supported by the Science and Technology Plan of Hebei Higher School of Education Department, China。
文摘In order to effectively predict the fracture of AA7075-T6 sheet, the forming limit curves of AA7075-T6 high-strength sheet were drawn according to Morciniak Kuczyski (M K) model and Lou Huh criterion, respectively. The errors between the predicted values of the two theoretical prediction models and experimental values were calculated by error analysis. The forming limit curves were verified by the punch stretch test to evaluate the prediction accuracy of M K model and Lou Huh criterion. The error analysis results show that the mean error of Lou Huh criterion with the optimal parameters for all tensile specimens is 25.04%, while the mean error of M K model for all tensile specimens is 74.24%. The prediction accuracy of Lou Huh criterion in predicting the fracture of AA7075-T6 sheet is higher. The punch stretch test results show that the forming limit curve drawn by Lou Huh criterion can effectively predict the fracture of AA7075-T6 sheet, but the prediction accuracy of M K model is relatively poor.
文摘Copper–ceria(Cu O–CeO2) catalysts have been known to be very effective for the oxidation of CO, and their chemical behavior has been extensively studied during the last decades. However, the effect of different CeO2 crystal surfaces on the catalytic activity of Cu O–CeO2 for the oxidation of CO is still unclear and should be further elucidated. In this study, we deposited 1 wt% Cu on mostly {100}-exposed CeO2 nanocubes(1 Cu Ce NC) and mostly {110}-exposed CeO2 nanorods(1 Cu Ce NR), respectively. Both 1 Cu Ce NC and 1 Cu Ce NR have been used as catalysts for the oxidation of CO and achieved 100% and 50% CO conversion at 130 ℃, respectively. The differences in the catalytic activity of 1 Cu Ce NC and 1 Cu Ce NR were analyzed using temperature-programmed reduction of H2 and temperature-programmed desorption of CO techniques. The results confirmed the excellent reducibility of the 1 Cu Ce NC catalyst, which was attributed to the weak interactions between Cu and the CeO2 support. Moreover, in situ diffuse reflectance infrared Fourier-transform spectroscopy studies indicated that the {100} planes of 1 Cu Ce NC facilitated the generation of active Cu(I) sites, which resulted in the formation of highly reactive Cu(I)-CO species during the oxidation of CO. Both the excellent redox properties and effective CO adsorption capacity of the 1 Cu Ce NC catalyst increased its catalytic reactivity.
基金Projects(51775138,U1537206)supported by the National Natural Science Foundation of ChinaProject(2015DFA50470)supported by the International Science&Technology Cooperation Program of ChinaProject(2017GGX40103)supported by the Key Research&Development Program of Shandong Province,China
文摘TiBw/TC4composite was brazed to Ti60alloy successfully using TiZrNiCu amorphous filler alloy,and the interfacialmicrostructures and mechanical properties were characterized by SEM,EDX,XRD and universal tensile testing machine.The typicalinterfacial microstructure was TiBw/TC4composite/β-Ti+TiB whiskers/(Ti,Zr)2(Ni,Cu)intermetallic layer/β-Ti/Ti60alloy whenbeing brazed at940°C for10min.The interfacial microstructure evolution was influenced strongly by the diffusion and reactionbetween molten fillers and the substrates.Increasing brazing temperature decreased the thickness of brittle(Ti,Zr)2(Ni,Cu)intermetallic layer,which disappeared finally when the brazing temperature exceeded1020°C.Fracture analyses indicated thatcracks were initialized in the brittle intermetallic layer when(Ti,Zr)2(Ni,Cu)phase existed in the brazing seam.The maximumaverage shear strength of joints reached368.6MPa when brazing was conducted at1020°C.Further increasing brazing temperatureto1060°C,the shear strength was decreased due to the formation of coarse lamellar(α+β)-Ti structure.
文摘In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.
基金financially supported by the Major Special Projects in Anhui Province,China(No.202003c08020005)the Key Projects in Hunan Province,China(No.2020GK2045).
文摘High-resolution transmission electron microscopy(TEM),X-ray diffractometer(XRD),and hardness test were used to study the evolution of long plate-shaped S'phase in the spray-formed fine-grained Al−Cu−Mg alloy during aging after rapid cold punching deformation.Results show that the long plate-shaped S'phase in the extruded Al−Cu−Mg alloy undergoes evident distortion,brittle failure,separation and redissolution,during rapid cold punching deformation,leading to the transformation of long plate-shaped S'phase into short rod or even redissolution and disappearance,causing the matrix to become a supersaturated solid solution.After the aging treatment,the reprecipitation of the phases occurs,and these aging phases are mainly long plate-shaped and granular.The incompletely dissolved S'phase acts as nucleation core,promoting uphill diffusion of the surrounding solute atoms.The S'phase gradually grows with increasing the aging time.The completely dissolved S'phase forms the incoherent equilibrium phase with the matrix to reduce its free energy.After rapid cold punching,the aging response of the deformed Al−Cu−Mg alloy is accelerated,and the hardness of the alloy is substantially increased.
基金Project(ZR2016EEQ03) supported by the Shandong Province Natural Science Foundation,ChinaProject(2018M641822) supported by the China Postdoctoral Science Foundation-General ProgramProject(HIT.NSRIF.201703) supported by the Natural Scientific Research Innovation Foundation in HIT,China
文摘The microstructure and mechanical properties of multi-layer multi-pass TIG welded joints of Al-Zn-Mg alloy plates were studied.The phase constituent and microstructure of different regions of the welded joints were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),transmission electron microscopy(TEM)and energy disperse spectrum(EDS),while the mechanical properties were evaluated according to the impact test.A dispersively distributed spherical and needle-likeη(MgZn2)phase was obtained in the welding seam.The phase composition of the heat-affected zone(HAZ)wasα(Al)+η(MgZn2)+Al6Mn,and there were a large number of dispersively precipitated nanoscale particles.The welded joint zone had the highest impact toughness as compared with the other parts of the joint.The MgZn2 phase in the weld zone contributed to the improved toughness of the joint.Al2 MgCu phase in HAZ was proven to act as a crack source during fracture.
基金Supported by National Natural Science Foundation of China(12101482)Postdoctoral Science Foundation of China(2022M722604)+2 种基金General Project of Science and Technology of Shaanxi Province(2023-YBSF-372)The Natural Science Foundation of Shaan Xi Province(2023-JCQN-0016)Shannxi Mathmatical Basic Science Research Project(23JSQ042)。
文摘In order to better describe the phenomenon of biological invasion,this paper introduces a free boundary model of biological invasion.Firstly,the right free boundary is added to the equation with logistic terms.Secondly,the existence and uniqueness of local solutions are proved by the Sobolev embedding theorem and the comparison principle.Finally,according to the relevant research data and contents of red fire ants,the diffusion area and nest number of red fire ants were simulated without external disturbance.This paper mainly simulates the early diffusion process of red fire ants.In the early diffusion stage,red fire ants grow slowly and then spread over a large area after reaching a certain number.
基金The authors would like to acknowledge the financial support from National Key Research and Development Program of China(2018YFB1107801 and 2018YFB1107802)Science Fund for Creative Research Groups of NSFC(51621064)+1 种基金National Natural Science Foundation of China(51790172)Fundamental Research Funds for the Central University(DUT19LAB06).
文摘To clarify the transformation mechanism of secondary phase and the mechanism of intergranular corrosion in laser welding Ni-based alloy (Hastelloy C-276)/304 stainless steel with filler wire,the secondary phase was analyzed by electron probe micro-analysis (EPMA) and transmission electron microscopy (TEM).The evaluation of intergranular corrosion resistance of the welded joints was conducted by double-loop electrochemical potentiokinetic reactivation(DL-EPR) method,and at the same time the chemical compositions of the corrosion surface were analyzed by energy-dispersive spectrometry (EDS).The results show that p phase has complete coherence relationship withμphase,and the coherent relationship is described as[001]p//■and[430]p//[0001]μ.Theμphase is rapidly transformed from p phase,which is the inhomogeneous phase transformation.The transformation of secondary phase will increase the susceptibility to intergranular corrosion.Therefore,the transformation of secondary phase should be avoided in the welding process.
文摘Three zinc(Ⅱ),cobalt(Ⅱ),and nickel(Ⅱ)coordination polymers,namely[Zn(μ^(3-)cpna)(μ-dpea)_(0.5)]_(n)(1),[Co(μ^(3-)cpna)(μ-dpey)_(0.5)]_(n)(2),and[Ni(μ^(3-)cpna)(μ-dpey)_(0.5)(H_(2)O)]_(n)(3),have been constructed hydrothermally using H_(2)cpna(5-(4-carboxyphenoxy)nicotinic acid),dpea(1,2-di(4-pyridyl)ethane),dpey(1,2-di(4-pyridyl)ethylene),and zinc,cobalt,and nickel chlorides at 160℃.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses,and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that three compounds crystallize in the triclinic system,space group P1.Compounds 1-3 show 2D layer structures.The catalytic activities in the Knoevenagel condensation reaction of these compounds were investigated.Compounds 1 and 2 exhibit effective catalytic activities in the Knoevenagel condensa-tion reaction at room temperature.For this reaction,various parameters were optimized,followed by the investiga-tion of the substrate scope.CCDC:2335676,1;2335677,2;2335678,3.
基金financial supports from the National Natural Science Foundation of China (Nos.51901068,51979099)the Key Research and Development Project of Jiangsu Province,China (No.BE2021027)+1 种基金the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,China (No.ASMA202102)the Research Fund from Key Laboratory for Light-weight Materials of Jiangsu Province,China。
文摘To investigate the effect of separate Al_(2)Ca and Mg_(2)Ca phases on the corrosion properties of Mg−Al−Ca−Mn alloys,OM,SEM,immersion and electrochemical tests were conducted on the as-cast and ECAP Al_(2)Ca-containing(2Ca)and Mg_(2)Ca-containing(4Ca)alloys.At the beginning of corrosion,the two as-cast alloys are corroded slowly compared with ECAP alloys.With prolonging the corrosion time,the corrosion of ECAP alloys becomes slighter than that of as-cast alloys,which is mainly ascribed to the dispersion and refinement of the second phase in ECAP alloys.Moreover,the corrosion degree of 2Ca alloys is always slighter than that of 4Ca alloys,suggesting that Al_(2)Ca phase is more beneficial to the enhancement of corrosion resistance of Mg−Al−Ca−Mn based alloys than Mg_(2)Ca phase.Finally,based on the examinations of corrosion surface and electrochemical testing results,different corrosion mechanisms caused by the distributions and morphology of Al_(2)Ca and Mg_(2)Ca phases are discussed.
文摘The development of an efficient artificial H_(2)O_(2) photosynthesis system is a challenging work using H_(2)O and O_(2) as starting materials.Herein,3D In_(2.77)S_(4) nanoflower precursor was in-situ deposited on K^(+)-doped g-C_(3)N_(4)(KCN)nanosheets using a solvothermal method,then In_(2.77)S_(4)/KCN(IS/KCN)het-erojunction with an intimate interface was obtained after a calcination process.The investigation shows that the photocatalytic H_(2)O_(2) production rate of 50IS/KCN can reach up to 1.36 mmol g^(-1)h^(-1)without any sacrificial reagents under visible light irradiation,which is 9.2 times and 4.1 times higher than that of KCN and In_(2.77)S_(4)/respectively.The enhanced activity of the above composite can be mainly attributed to the S-scheme charge transfer route between KCN and In_(2.77)S_(4) according to density functional theory calculations,electron paramagnetic resonance and free radical capture tests,leading to an expanded light response range and rapid charge separation at their interface,as well as preserving the active electrons and holes for H_(2)O_(2) production.Besides,the unique 3D nanostructure and surface hydrophobicity of IS/KCN facilitate the diffusion and transportation of O_(2) around the active centers,the energy barriers of O_(2) protonation and H_(2)O_(2) desorption steps are ef-fectively reduced over the composite.In addition,this system also exhibits excellent light harvesting ability and stability.This work provides a potential strategy to explore a sustainable H_(2)O_(2) photo-synthesis pathway through the design of heterojunctions with intimate interfaces and desired reac-tion thermodynamics and kinetics.
