Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media...Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media during their service.Traditionally,observing the in-situ degradation process of refractory materials in complex high-temperature environments has presented challenges.Post-corrosion analysis are commonly employed to assess the slag resistance of refractory materials and understand the corrosion mechanisms.However,these methods often lack information on the process under the conditions of thermal-chemical-mechanical coupling,leading to potential biases in the analysis results.In this work,we developed a non-contact high-temperature machine vision technology by the integrating Digital Image Correlation(DIC)with a high-temperature visualization system to explore the corrosion behavior of Al2O3-SiO2 refractories against molten glass and Al2O3-MgO dry ramming refractories against molten slag at different temperatures.This technology enables realtime monitoring of the 2D or 3D overall strain and average strain curves of the refractory materials and provides continuous feedback on the progressive corrosion of the materials under the coupling conditions of thermal,chemical,and mechanical factors.Therefore,it is an innovative approach for evaluating the service behavior and performance of refractory materials,and is expected to promote the digitization and intelligence of the refractory industry,contributing to the optimization and upgrading of product performance.展开更多
1. Introduction Thermodynamics forms the fundamental underpinning of reactivity, transformation, and stability, and controls processes such as synthesis, corrosion and degradation, environmental transport, catalysis, ...1. Introduction Thermodynamics forms the fundamental underpinning of reactivity, transformation, and stability, and controls processes such as synthesis, corrosion and degradation, environmental transport, catalysis, and biological reactivity. In the materials field, the wealth of new compounds, polymorphs, hybrid organic–inorganic hybrid materials and metal organic frameworks, high-entropy alloys, and multiphase and nanophase materials attained by a variety of non-equilibrium synthesis and processing methodologies has outrun the available thermodynamic data, hampering current understanding of synthetic pathways, materials compatibility, and longevity during use, degradation, corrosion, and dissolution, and limiting our understanding of environmental contamination and transport for new materials.展开更多
Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability...Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.展开更多
Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PS...Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PSDs operating at high temperatures can be found up to now.Herein,we design a new 2D/3D graphitic carbon nitride(g-C_(3)N_(4))/gallium nitride(GaN)hybrid heterojunction to construct the ultraviolet high-temperature-resistant PSD.The g-C_(3)N_(4)/GaN PSD exhibits a high position sensitivity of 355 mV mm^(-1),a rise/fall response time of 1.7/2.3 ms,and a nonlinearity of 0.5%at room temperature.The ultralow formation energy of-0.917 eV atom^(-1)has been obtained via the thermodynamic phase stability calculations,which endows g-C_(3)N_(4)with robust stability against heat.By merits of the strong built-in electric field of the 2D/3D hybrid heterojunction and robust thermo-stability of g-C_(3)N_(4),the g-C_(3)N_(4)/GaN PSD delivers an excellent position sensitivity and angle detection nonlinearity of 315 mV mm^(-1)and 1.4%,respectively,with high repeatability at a high temperature up to 700 K,outperforming most of the other counterparts and even commercial silicon-based devices.This work unveils the high-temperature PSD,and pioneers a new path to constructing g-C_(3)N_(4)-based harsh-environment-tolerant optoelectronic devices.展开更多
A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and wei...A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and weightlessness. The mechanism on which the material relies is similar to 'sponge' trapping the liquid cryogens within its micro-pores with surface tension. Preliminary tests have been performed on wicking. Also,we apply the materials to the cryogenic optical cooler whjch needs to be maintained within the temperuture range of 80-100 K. The results are satisfactory.展开更多
In this study, laponite was tested as a mud-making material for drilling fluids. Laponite is a synthetic smectite clay with a structure and composition closely resembling the natural clay mineral hectorite. Commercial...In this study, laponite was tested as a mud-making material for drilling fluids. Laponite is a synthetic smectite clay with a structure and composition closely resembling the natural clay mineral hectorite. Commercially available laponite was characterized by X-ray di ractometry, scanning electron microscopy and infrared spectrometry. Its dispersibility, salt resistance and high-temperature resistance were evaluated. The results showed that laponite possessed superior cation exchange capacity(140.4 mmol/100 g) with interlayer cations of Na^+ and Li^+. Laponite could easily be dispersed in water to yield increased viscosity with no influence from hydration time or temperature. On the other hand, laponite dispersions displayed an excellent heat resistance, with invariant apparent viscosity at high temperatures. For instance, the apparent viscosity of the2 wt% laponite dispersion underwent changes between 22 and 24 mPa s after hot rolling at 180–240 °C for 16 h. Compared to existing mud-making materials, laponite exhibited better mud-making properties. Furthermore, laponite revealed good compatibility with other additives, and the water-based drilling fluids prepared with laponite as mud-making material showed an excellent stability at elevated temperatures and superior performance–cost ratios. Overall, these findings indicated that laponite had an excellent dispersibility at high temperatures and hence would have promising applications as high-temperature mud-making material for preparing water-based drilling fluids designed for ultra-high-temperature environments.展开更多
In this paper the alkali-activated slag cementitious materials(AASCM)which strength at 600 ℃ is larger than that of AASCM at room temperature,were prepared to paste CFRP sheets to strengthen four simply supported unb...In this paper the alkali-activated slag cementitious materials(AASCM)which strength at 600 ℃ is larger than that of AASCM at room temperature,were prepared to paste CFRP sheets to strengthen four simply supported unbonded prestressed composite beams encased circular steel tube truss after ultimate limit state.Test on flexural behavior of these four beams was performed.Moreover,normal section load-bearing capacity of these beams and the curve load-deflection at mid-span were obtained.Experimental results show that it is feasible to strengthen concrete members with CFRP sheets bonded with AASCM.Based on the experimental results and theoretical study,computational method of stiffness is proposed for calculating bending rigidity and normal section load-bearing capacity of concrete simply supported beams strengthened with CFRP sheets bonded with AASCM.Formula of bending rigidity calculation was founded which results are in good agreement with testing data.展开更多
A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-...A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-temperature heat flux generated by the combustion of the samples from the eruption device was used to penetrate the Q235 target plate.In addition,the meaning and calculation formula of energy density characterising the all-around performance of heat flux were proposed.The numerical simulation of the combustion effect of samples was carried out.According to the data comparison,the numerical simulation results agreed with the experimental results,and the maximum deviation between the two was less than 8.9%.In addition,the structure of the combustion wave and high-temperature jet was proposed and analysed.Based on theoretical analysis,experimental research and numerical simulation,the theoretical burning rate formula of the sample was established.The maximum error between the theoretically calculated mass burning rate and the experimental results was less than 9.8%.Therefore,using the gas-phase steady-state combustion model to study the combustion characteristics of solid sustained-release energetic materials was reasonable.The theoretical burning rate formula also had high accuracy.Therefore,the model could provide scientific and academic guidance for the theoretical research,system design and practical application of solid sustained-release energetic materials in related fields.展开更多
In order to realize the large-scale and high-value utilization of waste architectural ceramics,high-temperature resistant materials based on waste architectural ceramics were prepared with sodium silicate as the binde...In order to realize the large-scale and high-value utilization of waste architectural ceramics,high-temperature resistant materials based on waste architectural ceramics were prepared with sodium silicate as the binder,clay/bauxite and metakaolin/bauxite as coating materials,and the cold strength obtaining mechanism was explored.The phase composition,the microstructure and the mechanical properties of the high temperature resistant materials based on waste architectural ceramics were tested and analyzed.The results showed that when the heat treatment temperature was between 110-1000℃,the strength of the samples mainly came from the physical adhesion of sodium silicate and fine powder.When the temperature rose to 1100℃,the strength of the sample was improved since the internal low-melting-point components melted and promoted sintering.The addition of clay and bauxite can effectively enhance the flexural strength of the samples when the heat treatment temperature is 1000℃.When the heat treatment temperature rises from 900 to 1000℃,the flexural strength of the samples will be enhanced owing to the formation of silica alumina spinel and mullite from metakaolin.展开更多
Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a lar...Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a large challenge to design such stimulus responsive materials,especially functional materials having both dielectric switch and second harmonic generation(SHG).Here,a new stimuli-responsive switchable material [(CH_(3))_(3)N(CH_(2))_(2)Cl]_(2)]Mn(SCN)_(4)(H_(2)O)_(2)] was discovered as a potential secondharmonic generation(SHG) dielectric switch.It is worth noting that it has SHG characteristics before and after undergoing reversible high-temperature phase transitions.In this work,we successfully refined the tetramethylammonium cation to obtain a quasi-spherical cation,which is tetramethylchloroethylamine(TMCEM) cation.By substituting H with a halogen,the increased steric hindrance of the molecular makes energy barrier increased,resulting in the reversible high-temperature phase transition.At the same time,the interactions of quasi-spherical cations and [Mn(SCN)_(4)(H_(2)O)_(2)]^(2-) anions affect a noncentrosymmetric structure to induce the SHG effect.These findings provide a new approach to design novel functional switch materials.展开更多
The need for very-high-cycle fatigue(VHCF)testing up to 1010cycles of aviation gas turbine engine blade materials under combined mechanical loads and complex environments has encouraged the development of VHCF testing...The need for very-high-cycle fatigue(VHCF)testing up to 1010cycles of aviation gas turbine engine blade materials under combined mechanical loads and complex environments has encouraged the development of VHCF testing instrumentation and technology.This article begins with a comprehensive review of the existing available techniques that enable VHCF testing.Recent advances in ultrasonic fatigue testing(UFT)techniques are highlighted,containing their new capabilities and methods for single load,multiaxial load,variable amplitude fatigue,and combined cycle fatigue.New techniques for conducting UFT in high-temperature,humid environments,and corrosive environments are summarized.These developments in mechanical loading and environmental building techniques provide the possibility of laboratory construction for real service conditions of blade materials.New techniques that can be used for in situ monitoring of VHCF damage are summarized.Key issues in the UFT field are presented,and countermeasures are collated.Finally,the existing problems and future trends in the field are briefly described.展开更多
B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,i...B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder surface.In this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al composites.It was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high temperature.As the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased significantly.The finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.展开更多
基金supported by the National Natural Science Foundation of China(52272022)Key Program of Natural Science Foundation of Hubei Province(2021CFA071).
文摘Refractory materials,as the crucial foundational materials in high-temperature industrial processes such as metallurgy and construction,are inevitably subjected to corrosion and penetration from high-temperature media during their service.Traditionally,observing the in-situ degradation process of refractory materials in complex high-temperature environments has presented challenges.Post-corrosion analysis are commonly employed to assess the slag resistance of refractory materials and understand the corrosion mechanisms.However,these methods often lack information on the process under the conditions of thermal-chemical-mechanical coupling,leading to potential biases in the analysis results.In this work,we developed a non-contact high-temperature machine vision technology by the integrating Digital Image Correlation(DIC)with a high-temperature visualization system to explore the corrosion behavior of Al2O3-SiO2 refractories against molten glass and Al2O3-MgO dry ramming refractories against molten slag at different temperatures.This technology enables realtime monitoring of the 2D or 3D overall strain and average strain curves of the refractory materials and provides continuous feedback on the progressive corrosion of the materials under the coupling conditions of thermal,chemical,and mechanical factors.Therefore,it is an innovative approach for evaluating the service behavior and performance of refractory materials,and is expected to promote the digitization and intelligence of the refractory industry,contributing to the optimization and upgrading of product performance.
基金the US Department of Energy, Office of Science,Basic Energy Sciences (DE-SC0001089)while that on ultra-ightemperature calorimetry was supported by the National Science Foundation DMR (1506229 and 1835848).
文摘1. Introduction Thermodynamics forms the fundamental underpinning of reactivity, transformation, and stability, and controls processes such as synthesis, corrosion and degradation, environmental transport, catalysis, and biological reactivity. In the materials field, the wealth of new compounds, polymorphs, hybrid organic–inorganic hybrid materials and metal organic frameworks, high-entropy alloys, and multiphase and nanophase materials attained by a variety of non-equilibrium synthesis and processing methodologies has outrun the available thermodynamic data, hampering current understanding of synthetic pathways, materials compatibility, and longevity during use, degradation, corrosion, and dissolution, and limiting our understanding of environmental contamination and transport for new materials.
基金supported by the Sichuan Science and Technology Program (Grant Nos.2023NSFSC0004,2023NSFSC0790)the National Natural Science Foundation of China (Grant Nos.51827901,52304033)the Sichuan University Postdoctoral Fund (Grant No.2024SCU12093)。
文摘Deep oil and gas reservoirs are under high-temperature conditions,but traditional coring methods do not consider temperature-preserved measures and ignore the influence of temperature on rock porosity and permeability,resulting in distorted resource assessments.The development of in situ temperaturepreserved coring(ITP-Coring)technology for deep reservoir rock is urgent,and thermal insulation materials are key.Therefore,hollow glass microsphere/epoxy resin thermal insulation materials(HGM/EP materials)were proposed as thermal insulation materials.The materials properties under coupled hightemperature and high-pressure(HTHP)conditions were tested.The results indicated that high pressures led to HGM destruction and that the materials water absorption significantly increased;additionally,increasing temperature accelerated the process.High temperatures directly caused the thermal conductivity of the materials to increase;additionally,the thermal conduction and convection of water caused by high pressures led to an exponential increase in the thermal conductivity.High temperatures weakened the matrix,and high pressures destroyed the HGM,which resulted in a decrease in the tensile mechanical properties of the materials.The materials entered the high elastic state at 150℃,and the mechanical properties were weakened more obviously,while the pressure led to a significant effect when the water absorption was above 10%.Meanwhile,the tensile strength/strain were 13.62 MPa/1.3%and 6.09 MPa/0.86%at 100℃ and 100 MPa,respectively,which meet the application requirements of the self-designed coring device.Finally,K46-f40 and K46-f50 HGM/EP materials were proven to be suitable for ITP-Coring under coupled conditions below 100℃ and 100 MPa.To further improve the materials properties,the interface layer and EP matrix should be optimized.The results can provide references for the optimization and engineering application of materials and thus technical support for deep oil and gas resource development.
基金financially supported by the National Natural Science Foundation of China(No.61804136,U1804155,11974317,62027816,12074348,and U2004168)Henan Science Fund for Distinguished Young Scholars(No.212300410020)+2 种基金Natural Science Foundation of Henan Province(No.212300410020 and 212300410078)Key Project of Henan Higher Education(No.21A140001)the Zhengzhou University Physics Discipline Improvement Program and China Postdoctoral Science Foundation(No.2018M630829 and 2019 T120630)
文摘Ultraviolet position-sensitive detectors(PSDs)are expected to undergo harsh environments,such as high temperatures,for a wide variety of applications in military,civilian,and aerospace.However,no report on relevant PSDs operating at high temperatures can be found up to now.Herein,we design a new 2D/3D graphitic carbon nitride(g-C_(3)N_(4))/gallium nitride(GaN)hybrid heterojunction to construct the ultraviolet high-temperature-resistant PSD.The g-C_(3)N_(4)/GaN PSD exhibits a high position sensitivity of 355 mV mm^(-1),a rise/fall response time of 1.7/2.3 ms,and a nonlinearity of 0.5%at room temperature.The ultralow formation energy of-0.917 eV atom^(-1)has been obtained via the thermodynamic phase stability calculations,which endows g-C_(3)N_(4)with robust stability against heat.By merits of the strong built-in electric field of the 2D/3D hybrid heterojunction and robust thermo-stability of g-C_(3)N_(4),the g-C_(3)N_(4)/GaN PSD delivers an excellent position sensitivity and angle detection nonlinearity of 315 mV mm^(-1)and 1.4%,respectively,with high repeatability at a high temperature up to 700 K,outperforming most of the other counterparts and even commercial silicon-based devices.This work unveils the high-temperature PSD,and pioneers a new path to constructing g-C_(3)N_(4)-based harsh-environment-tolerant optoelectronic devices.
文摘A new kind of material used in liquid cryogen cooler has been found and investigated in our group It is anticipated that the materials can be applied in the conditions of launching, rotation in any orientation and weightlessness. The mechanism on which the material relies is similar to 'sponge' trapping the liquid cryogens within its micro-pores with surface tension. Preliminary tests have been performed on wicking. Also,we apply the materials to the cryogenic optical cooler whjch needs to be maintained within the temperuture range of 80-100 K. The results are satisfactory.
基金financially supported by the NSF of China(No.41502345)
文摘In this study, laponite was tested as a mud-making material for drilling fluids. Laponite is a synthetic smectite clay with a structure and composition closely resembling the natural clay mineral hectorite. Commercially available laponite was characterized by X-ray di ractometry, scanning electron microscopy and infrared spectrometry. Its dispersibility, salt resistance and high-temperature resistance were evaluated. The results showed that laponite possessed superior cation exchange capacity(140.4 mmol/100 g) with interlayer cations of Na^+ and Li^+. Laponite could easily be dispersed in water to yield increased viscosity with no influence from hydration time or temperature. On the other hand, laponite dispersions displayed an excellent heat resistance, with invariant apparent viscosity at high temperatures. For instance, the apparent viscosity of the2 wt% laponite dispersion underwent changes between 22 and 24 mPa s after hot rolling at 180–240 °C for 16 h. Compared to existing mud-making materials, laponite exhibited better mud-making properties. Furthermore, laponite revealed good compatibility with other additives, and the water-based drilling fluids prepared with laponite as mud-making material showed an excellent stability at elevated temperatures and superior performance–cost ratios. Overall, these findings indicated that laponite had an excellent dispersibility at high temperatures and hence would have promising applications as high-temperature mud-making material for preparing water-based drilling fluids designed for ultra-high-temperature environments.
基金Sponsored by the Changjiang Scholars Program of China(Grant No.2009-37)the National Natural Science Foundation of China(Grant No.50678050)
文摘In this paper the alkali-activated slag cementitious materials(AASCM)which strength at 600 ℃ is larger than that of AASCM at room temperature,were prepared to paste CFRP sheets to strengthen four simply supported unbonded prestressed composite beams encased circular steel tube truss after ultimate limit state.Test on flexural behavior of these four beams was performed.Moreover,normal section load-bearing capacity of these beams and the curve load-deflection at mid-span were obtained.Experimental results show that it is feasible to strengthen concrete members with CFRP sheets bonded with AASCM.Based on the experimental results and theoretical study,computational method of stiffness is proposed for calculating bending rigidity and normal section load-bearing capacity of concrete simply supported beams strengthened with CFRP sheets bonded with AASCM.Formula of bending rigidity calculation was founded which results are in good agreement with testing data.
文摘A solid sustained-release energetic material sample,an eruption device and a complete test system were prepared further to analyse the combustion characteristics of solid sustainedrelease energetic materials.The high-temperature heat flux generated by the combustion of the samples from the eruption device was used to penetrate the Q235 target plate.In addition,the meaning and calculation formula of energy density characterising the all-around performance of heat flux were proposed.The numerical simulation of the combustion effect of samples was carried out.According to the data comparison,the numerical simulation results agreed with the experimental results,and the maximum deviation between the two was less than 8.9%.In addition,the structure of the combustion wave and high-temperature jet was proposed and analysed.Based on theoretical analysis,experimental research and numerical simulation,the theoretical burning rate formula of the sample was established.The maximum error between the theoretically calculated mass burning rate and the experimental results was less than 9.8%.Therefore,using the gas-phase steady-state combustion model to study the combustion characteristics of solid sustained-release energetic materials was reasonable.The theoretical burning rate formula also had high accuracy.Therefore,the model could provide scientific and academic guidance for the theoretical research,system design and practical application of solid sustained-release energetic materials in related fields.
基金the National Key R & D Program of China (2018YFC1901501, 2018YFC1901503 and 2018YFC1901504)
文摘In order to realize the large-scale and high-value utilization of waste architectural ceramics,high-temperature resistant materials based on waste architectural ceramics were prepared with sodium silicate as the binder,clay/bauxite and metakaolin/bauxite as coating materials,and the cold strength obtaining mechanism was explored.The phase composition,the microstructure and the mechanical properties of the high temperature resistant materials based on waste architectural ceramics were tested and analyzed.The results showed that when the heat treatment temperature was between 110-1000℃,the strength of the samples mainly came from the physical adhesion of sodium silicate and fine powder.When the temperature rose to 1100℃,the strength of the sample was improved since the internal low-melting-point components melted and promoted sintering.The addition of clay and bauxite can effectively enhance the flexural strength of the samples when the heat treatment temperature is 1000℃.When the heat treatment temperature rises from 900 to 1000℃,the flexural strength of the samples will be enhanced owing to the formation of silica alumina spinel and mullite from metakaolin.
基金supported by the National Natural Science Foundation of China(Nos.21673038,21771037,21805033)Natural Science Foundation of Jiangsu Province(JSNSF,No.BK20170659)。
文摘Stimulus re s ponsive materials can provide a variety of desirable properties in one equipment unit,such as optoelectronic devices,data communications,actuators,memories,sensors and capacitors.However,it remains a large challenge to design such stimulus responsive materials,especially functional materials having both dielectric switch and second harmonic generation(SHG).Here,a new stimuli-responsive switchable material [(CH_(3))_(3)N(CH_(2))_(2)Cl]_(2)]Mn(SCN)_(4)(H_(2)O)_(2)] was discovered as a potential secondharmonic generation(SHG) dielectric switch.It is worth noting that it has SHG characteristics before and after undergoing reversible high-temperature phase transitions.In this work,we successfully refined the tetramethylammonium cation to obtain a quasi-spherical cation,which is tetramethylchloroethylamine(TMCEM) cation.By substituting H with a halogen,the increased steric hindrance of the molecular makes energy barrier increased,resulting in the reversible high-temperature phase transition.At the same time,the interactions of quasi-spherical cations and [Mn(SCN)_(4)(H_(2)O)_(2)]^(2-) anions affect a noncentrosymmetric structure to induce the SHG effect.These findings provide a new approach to design novel functional switch materials.
基金funded by the National Science Fund for Distinguished Young Scholars(Grant No.51925504)the National Key R and D Program of China(Grant No.2018YFF01012400)+4 种基金the National Key R&D Program of China(Grant No.2022YFA1604000)the National Major Scientific Research Instrument Development Project(Grant No.52227810)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.52021003)the National Natural Science Foundation of China(Grant No.52075220)the Jilin Provincial Department of Science and Technology Fund Project(Grant No.20210101056JC)。
文摘The need for very-high-cycle fatigue(VHCF)testing up to 1010cycles of aviation gas turbine engine blade materials under combined mechanical loads and complex environments has encouraged the development of VHCF testing instrumentation and technology.This article begins with a comprehensive review of the existing available techniques that enable VHCF testing.Recent advances in ultrasonic fatigue testing(UFT)techniques are highlighted,containing their new capabilities and methods for single load,multiaxial load,variable amplitude fatigue,and combined cycle fatigue.New techniques for conducting UFT in high-temperature,humid environments,and corrosive environments are summarized.These developments in mechanical loading and environmental building techniques provide the possibility of laboratory construction for real service conditions of blade materials.New techniques that can be used for in situ monitoring of VHCF damage are summarized.Key issues in the UFT field are presented,and countermeasures are collated.Finally,the existing problems and future trends in the field are briefly described.
基金supported by the National Key R&D Program of China(Grant No.2023YFB3710601)the National Natural Science Foundation of China(Grant Nos.52203385 and 52171056)+2 种基金the CNNC Science Fund for Talented Young Scholars,the Institute of Metal Research(IMR)Innovation Fund(Grant No.2021-ZD02)the Natural Science Foundation of Liaoning Province(Grant No.2022-BS-009)Young Elite Scientists Sponsorship Program by CAST(Grant No.YESS20220225).
文摘B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear fuel.In order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder surface.In this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al composites.It was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high temperature.As the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased significantly.The finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.
