The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition t...The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition temperature while increasing the crystallization peak temperature and lowering activation energy,which facilitated crystallization.The crystal growth shifted from three-dimensional to two-dimensional,and the primary phases transitioned from Al_(9.83)Zr_(0.17)and Y_(2)Si_(2)O_(7)to Y_(4.67)(SiO_(4))_(3)O,though crystal morphology remained unchanged.Grain size increased with higher crystallization temperatures.Mechanically,Vickers hardness slightly decreased(from 796 to 784 Hv),while bending strength improved(from 141 to 146 MPa),suggesting that TiO_(2)enhanced toughness without compromising structural integrity.The strength of the glass can be further improved through two-step ion exchange,but excessive crystallization can lead to cracks on the glass surface due to excessive surface compressive stress,resulting in a decrease in bending strength.These findings provide critical insights for optimizing YLAS glass-ceramics for advanced applications.展开更多
Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating w...Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of (()^(17)O-NMR) for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.展开更多
Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial ...Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial materials chip technology, featuring high-throughput synthesis and characterization, is able to determine the phase diagram of an entire composition spread of a binary or ternary system at a single temperature on one materials library, which, though significantly increasing efficiency, still requires many libraries processed at a series of temperatures in order to complete a phase diagram. In this paper, we propose a "one-chip method" to construct a complete phase diagram by individually synthesizing each pixel step by step with a progressive pulse of energy to heat at different temperatures while monitoring the phase evolution on the pixel in situ in real time. Repeating this process pixel by pixel throughout the whole chip allows the entire binary or ternary phase diagram to be mapped on one chip in a single experiment. The feasibility of this methodology is demonstrated in a study of a Ge-Sb-Te ternary alloy system, on which the amorphouscrystalline phase boundary is determined.展开更多
The fused cast alumina-zirconia-silica(AZS)refractory is an indispensable material of the glass melting furnace,because of its outstanding corrosion resistance and low pollution to glass production.The exudation is on...The fused cast alumina-zirconia-silica(AZS)refractory is an indispensable material of the glass melting furnace,because of its outstanding corrosion resistance and low pollution to glass production.The exudation is one important index to evaluate the performance of fused cast AZS refractory products.In order to study the effects of chemical composition and microstructure on the exudation of fused cast AZS refractory materials,three types of fused-cast AZS refractory bricks(AZS33#,AZS36#and AZS41#)were selected from several companies as the research object,and their composition,bulk density,apparent porosity,the value of exudation,static corrosion rate and microstructure were discussed.The results show that the chemical composition,especially the content of SiO2 and Na2O,and the distribution of zirconia would greatly affect the content and viscosity of glass phase,thus affecting the glass exudation.This work will provide technical reference for the development of low exudation AZS refractories.展开更多
Hydration-heat-inhibiting materials(HIM)with polysaccharide as core material was prepared using microcapsule sustained-releasing technology,through a centrifugal spray granulation process after melting together.The pr...Hydration-heat-inhibiting materials(HIM)with polysaccharide as core material was prepared using microcapsule sustained-releasing technology,through a centrifugal spray granulation process after melting together.The preparation process parameters of HIM were selected by the semi-adiabatic temperature rise test of cement paste.TAM air microcalorimeter was used to investigate the regulation performance of HIM on the hydration of cement.The influence of HIM on the microstructure of cement was investigated by XRD,SEM,and TG-DSC.The results showed that the most suitable wall material for HIM was polyethylene wax,the optimum polyethylene wax/polysaccharide mass ratio was 1,and the most effective particle size was 0.16-0.30 mm.Polysaccharide coated by polyethylene wax released slowly,and the peak heat release rate of cement could be reduced by 55.2%after continuous regulaion.The regulation period continued to 120 h.HIM mainly decreased the C3S reaction rate,which resulted in a 39.2%peak value reduction of hydration heat release rate.However,HIM had little regulation on C3A.The hydration heat release process of cement-based materials can be designed by adjusting the dosage of HIM.展开更多
Based on the structural characteristics of the high-speed loading tester,a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and dif...Based on the structural characteristics of the high-speed loading tester,a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and different impact velocities,and the formulae for calculating the maximum dynamic stress and strain rate of glass specimens under the action of impact loads were derived.The experimental results show that the bending strength values of the glass under dynamic impact loading are all higher than those under static loading.With the increase of impact speed,the bending strength value of glass specimens generally tends to increase,and the bending strength value increases more obviously when the impact speed exceeds 0.5 m/s or higher.By increasing the impact velocity,higher tensile strain rate of glass specimens can be obtained because the load action time becomes shorter.The bending strength of the glass material increases with its tensile strain rate,and when the tensile strain rate is between 0 and 2 s^(-1),the bending strength of the glass specimen grows more obviously with the strain rate,indicating that the glass bending strength is particularly sensitive to the tensile strain rate in this interval.As the strain rate increases,the number of cracks formed after glass breakage increases significantly,thus requiring more energy to drive the crack formation and expansion,and showing the strain rate effect of bending strength at the macroscopic level.The results of the study can provide a reference for the load bearing and structural design of glass materials under dynamic loading.展开更多
Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods w...Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods were developed for quantitative determination of fly ash, slag and limestone powder in fresh cement pastes, mortars and concretes. Limestone powder was determined using thermal analysis method. The residue content of fly ash on an 80um sieve, and silt contents of aggregate were also considered during the quantitative determination of mineral composition of quaternary cementitious system. With the developed methods, the deviations between the measured and the actual mineral contents of the constituent in the eemantitious material in fresh cement paste, mortar and concrete, were within 3%.展开更多
The properties of rare earth materials activated diesel oil such as temperature, density and hydroxylic radical were discussed. Rare earth materials including minim thorium oxide powders which had radioactivity were m...The properties of rare earth materials activated diesel oil such as temperature, density and hydroxylic radical were discussed. Rare earth materials including minim thorium oxide powders which had radioactivity were mainly composed of rare earth waste-residue powders. Under the radiation catalysis of rare earth materials, molecules of diesel oil can be transformed into activated molecules, the collision frequency increases among molecules, and temperature raises a little higher than usual. When temperature is higher, the interaction force between molecules is lessened, distance between molecules is shortened. The volume is increased and the density is decreased. A large amounts electrons and negative ions are produced by rare earth materials, which leads to the signals of hydroxylic radical stronger that means rare earth materials can activate diesel oil and can improve the activity of diesel oil.展开更多
It is difficult to ensure the manufacturing process of composites for the reason that there are complicated processes during curing process of composites. The cure cycle has a significant effect on the quality of the ...It is difficult to ensure the manufacturing process of composites for the reason that there are complicated processes during curing process of composites. The cure cycle has a significant effect on the quality of the finished part. The traditional cure cycle based on empirical approach could not ensure the quality of cured products because of unstabilized performance, high cost of production and low efficiency. As complex intelligent manufacturing systems are developed increasingly in industry, the necessity of more user friendly operation system is becoming progressively importance for their utilization and market value. This paper introduces some of the recent technological advances in the intelligent manufacturing systems that will influence the design and development of relevant industry.展开更多
By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimizatio...By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.展开更多
Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(gen...Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.展开更多
Purpose–This paper aims to analyze the transverse vibration characteristics of the high speed train window glass when passing through tunnel.Design/methodology/approach–The lateral vibration acceleration response of...Purpose–This paper aims to analyze the transverse vibration characteristics of the high speed train window glass when passing through tunnel.Design/methodology/approach–The lateral vibration acceleration response of glass chamber of high-speed train CR400BF-A on Beijing-Chengdu high-speed railway was tested at different speeds through the tunnel entrance,exit,tunnel interior,Tunnel Group and rendezvous time in the tunnel,the lateral distribution characteristics of vibration frequency and vibration power amplification coefficient of glass of high-speed train were analyzed.Findings–The results show that:The vibration of the high-speed train glass increases significantly during the tunnel,and the amplitude of vibration acceleration in the tunnel is significantly higher than outside the tunnel as the travel speed increases;the amplitude of lateral vibration acceleration of the glass of a high-speed train does not vary with changes in tunnel length and is not affected by the aerodynamic effects of the tunnel when traveling inside the tunnel,but its vibrations create noticeable fluctuations during variations when encountering oncoming traffic;The vibration characteristics of the high-speed train glass are forced harmonic vibrations,the excitation frequency does not vary with travel speed and travel position changes inside and outside the tunnel.The lateral vibration acceleration of the glass of a high-speed train is applied vertically and uniformly to the glass surface as an“inertial force”and creates a cyclic bending vibration stress that can easily lead to fatigue damage.Originality/value–The research results provide guidance for the prevention of glass failure in high-speed trains.展开更多
Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship betw...Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.展开更多
The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and ...The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and SEN were performed by tensile and bending load-displacement relationships,and the effects of notch depth on notch sensitivity were determined by DEN specimens.The results from mechanical tests indicated that the SEN exhibited a brittle behaviour with linear elasticity,while the DEN exhibited a ductile behaviour with nonlinearity.It was also found that increasing notch depth and decreasing ligament width can lead to a higher ultimate tensile strength of DEN.On the other hand,the digital image correlation(DIC)method and acoustic emission(AE)system were also applied during the mechanical tests to study the local mechanical characteristics of shear damage,strain concentration and fracture behaviour of 2D C/Cs.The results revealed the mechanisms of notch insensitivity and explained the differences in fracture behaviours between SEN and DEN.展开更多
We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron gen...We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron generation and energy deposition,we found that 1.0 MeV electrons and protons produce 67.5 and 67 secondary electrons per particle,respectively,compared to 116 from 1.25 MeV gamma rays in thick targets.Boltzmann-function fitting revealed depth-dependent ionization equivalence:0.582 gamma photons match the secondary electron yield of a 1.0 MeV electron,and 0.577 gamma photons match a 1.0 MeV proton.These results establish a framework to convert ground-based gamma-ray test data to space environment scenarios,accounting for critical differences in penetration depth-protons deposit energy within 10μm(coating layers),while gamma rays penetrate>100 mm into substrates.This provides a theoretical basis for evaluating radiation effects using existing^(60)Co facilities,enabling reliable predictions of optical component durability in complex space environments.展开更多
We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subse...We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.展开更多
The viscosity of anti-irradiated glass was quantitatively characterized using beam bending viscometry(BBV),parallel plate viscometry(PPV),and rotational viscometry(RV).The Vogel-Fulcher-Tammann(VFT)equation was determ...The viscosity of anti-irradiated glass was quantitatively characterized using beam bending viscometry(BBV),parallel plate viscometry(PPV),and rotational viscometry(RV).The Vogel-Fulcher-Tammann(VFT)equation was determined to be the most suitable for representing the viscosity-temperature characteristics of anti-irradiation glass by comparing the fitting effects and accuracy of different equations within different test ranges.The fragility index m of anti-irradiation glass was 47.5,as calculated using an Angell plot,and the cause of the appropriate fit of the VFT equation was analyzed.The effects of different heating temperatures and loading rates on the tensile properties of glass were studied using a universal testing machine.The results indicated that,at a tensile rate of 10 mm/s,the heating temperature increased from 903 to 1023 K,and the deformation process of anti-irradiation glass transitioned from unstable to stable.When the tensile rate increased from 10 to 30 mm/s at 1023 K,the deformation process of the glass was extremely unstable.This work provides theoretical guidance for the large-size preparation of flexible anti-irradiation glass.展开更多
In this study,we developed an in-situ hot-pressing sintering(HPS)device that can be coupled to a lab-oratory X-ray microscope,offering laboratory-available observation of the morphology evolution.With the help of this...In this study,we developed an in-situ hot-pressing sintering(HPS)device that can be coupled to a lab-oratory X-ray microscope,offering laboratory-available observation of the morphology evolution.With the help of this device,in-situ three-dimensional(3D)visualizations of the microstructural evolution of 7055 aluminum alloys during the HPS process were conducted.The 3D results revealed that the twodimensional(2D)methods usually underestimated sintering neck width and exhibited significant standard deviation in statistical analysis.Benefiting from the precise microstructure characterization of the insitu 3D methods,the diffusion activation energy for the sintering of 7055 alloys was calculated,and the quantitative relationship between the sintering temperature and the sintering process was constructed.Moreover,it was experimentally found an accelerative effect of satellite particles on the sintering process,and its mechanisms were discussed.The satellite particles enhanced the curvature near the sintering neck and thus increased the sintering driving stress,promoting the densification process.These findings provide new insights for optimizing sintering processes.展开更多
基金Funded by the China Building Material Federation Projects(Nos.20221JBGS06-19 and 2023JBGS02-01)。
文摘The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition temperature while increasing the crystallization peak temperature and lowering activation energy,which facilitated crystallization.The crystal growth shifted from three-dimensional to two-dimensional,and the primary phases transitioned from Al_(9.83)Zr_(0.17)and Y_(2)Si_(2)O_(7)to Y_(4.67)(SiO_(4))_(3)O,though crystal morphology remained unchanged.Grain size increased with higher crystallization temperatures.Mechanically,Vickers hardness slightly decreased(from 796 to 784 Hv),while bending strength improved(from 141 to 146 MPa),suggesting that TiO_(2)enhanced toughness without compromising structural integrity.The strength of the glass can be further improved through two-step ion exchange,but excessive crystallization can lead to cracks on the glass surface due to excessive surface compressive stress,resulting in a decrease in bending strength.These findings provide critical insights for optimizing YLAS glass-ceramics for advanced applications.
文摘Antibacterial ceramic was prepared by doping enamel slurry with composite phosphate inorganic antibacterial materials containing rare earth (inorganic antibacterial additives), and then the mechanisms for activating water and improving seed germinative property were tested by nuclear magnetic resonance (NMR) and the method of testing oxygen dissolved in activated water. Results show that the half peak width of (()^(17)O-NMR) for tap water activated by the antibacterial ceramic drops from 115.36 to 99.15 Hz, and oxygen concentrations of activated water increase by 20%, germinate rate of horsebean and earthnut seeds increases by 12.5% and 7.5%, respectively. Therefore antibacterial ceramic doped enamel slurry with inorganic antibacterial additives containing rare earth can reduce the volume of clusters of water molecules, improve activation of tap water, and promote plant seeds germinate.
基金supported in part by National High Technology Research and Development Program (2015AA034204)the National Natural Science Foundation of China (51472044)
文摘Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial materials chip technology, featuring high-throughput synthesis and characterization, is able to determine the phase diagram of an entire composition spread of a binary or ternary system at a single temperature on one materials library, which, though significantly increasing efficiency, still requires many libraries processed at a series of temperatures in order to complete a phase diagram. In this paper, we propose a "one-chip method" to construct a complete phase diagram by individually synthesizing each pixel step by step with a progressive pulse of energy to heat at different temperatures while monitoring the phase evolution on the pixel in situ in real time. Repeating this process pixel by pixel throughout the whole chip allows the entire binary or ternary phase diagram to be mapped on one chip in a single experiment. The feasibility of this methodology is demonstrated in a study of a Ge-Sb-Te ternary alloy system, on which the amorphouscrystalline phase boundary is determined.
文摘The fused cast alumina-zirconia-silica(AZS)refractory is an indispensable material of the glass melting furnace,because of its outstanding corrosion resistance and low pollution to glass production.The exudation is one important index to evaluate the performance of fused cast AZS refractory products.In order to study the effects of chemical composition and microstructure on the exudation of fused cast AZS refractory materials,three types of fused-cast AZS refractory bricks(AZS33#,AZS36#and AZS41#)were selected from several companies as the research object,and their composition,bulk density,apparent porosity,the value of exudation,static corrosion rate and microstructure were discussed.The results show that the chemical composition,especially the content of SiO2 and Na2O,and the distribution of zirconia would greatly affect the content and viscosity of glass phase,thus affecting the glass exudation.This work will provide technical reference for the development of low exudation AZS refractories.
基金Funded by National Key R&D Program of China(No.2017YFB0310102)。
文摘Hydration-heat-inhibiting materials(HIM)with polysaccharide as core material was prepared using microcapsule sustained-releasing technology,through a centrifugal spray granulation process after melting together.The preparation process parameters of HIM were selected by the semi-adiabatic temperature rise test of cement paste.TAM air microcalorimeter was used to investigate the regulation performance of HIM on the hydration of cement.The influence of HIM on the microstructure of cement was investigated by XRD,SEM,and TG-DSC.The results showed that the most suitable wall material for HIM was polyethylene wax,the optimum polyethylene wax/polysaccharide mass ratio was 1,and the most effective particle size was 0.16-0.30 mm.Polysaccharide coated by polyethylene wax released slowly,and the peak heat release rate of cement could be reduced by 55.2%after continuous regulaion.The regulation period continued to 120 h.HIM mainly decreased the C3S reaction rate,which resulted in a 39.2%peak value reduction of hydration heat release rate.However,HIM had little regulation on C3A.The hydration heat release process of cement-based materials can be designed by adjusting the dosage of HIM.
基金Found by the National Natural Science Foundation of China(Nos.52072356 and 52032011)the Shandong Province Science and Technology Small and Medium-sized Enterprises Innovation Ability Improvement Project(No.2022TSGC1194)。
文摘Based on the structural characteristics of the high-speed loading tester,a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and different impact velocities,and the formulae for calculating the maximum dynamic stress and strain rate of glass specimens under the action of impact loads were derived.The experimental results show that the bending strength values of the glass under dynamic impact loading are all higher than those under static loading.With the increase of impact speed,the bending strength value of glass specimens generally tends to increase,and the bending strength value increases more obviously when the impact speed exceeds 0.5 m/s or higher.By increasing the impact velocity,higher tensile strain rate of glass specimens can be obtained because the load action time becomes shorter.The bending strength of the glass material increases with its tensile strain rate,and when the tensile strain rate is between 0 and 2 s^(-1),the bending strength of the glass specimen grows more obviously with the strain rate,indicating that the glass bending strength is particularly sensitive to the tensile strain rate in this interval.As the strain rate increases,the number of cracks formed after glass breakage increases significantly,thus requiring more energy to drive the crack formation and expansion,and showing the strain rate effect of bending strength at the macroscopic level.The results of the study can provide a reference for the load bearing and structural design of glass materials under dynamic loading.
基金Funded by the National Natural Science Foundation of China(50978093 and 51072050)the National Key Research Program(973 Project)(No.2009CB6231001)
文摘Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods were developed for quantitative determination of fly ash, slag and limestone powder in fresh cement pastes, mortars and concretes. Limestone powder was determined using thermal analysis method. The residue content of fly ash on an 80um sieve, and silt contents of aggregate were also considered during the quantitative determination of mineral composition of quaternary cementitious system. With the developed methods, the deviations between the measured and the actual mineral contents of the constituent in the eemantitious material in fresh cement paste, mortar and concrete, were within 3%.
文摘The properties of rare earth materials activated diesel oil such as temperature, density and hydroxylic radical were discussed. Rare earth materials including minim thorium oxide powders which had radioactivity were mainly composed of rare earth waste-residue powders. Under the radiation catalysis of rare earth materials, molecules of diesel oil can be transformed into activated molecules, the collision frequency increases among molecules, and temperature raises a little higher than usual. When temperature is higher, the interaction force between molecules is lessened, distance between molecules is shortened. The volume is increased and the density is decreased. A large amounts electrons and negative ions are produced by rare earth materials, which leads to the signals of hydroxylic radical stronger that means rare earth materials can activate diesel oil and can improve the activity of diesel oil.
文摘It is difficult to ensure the manufacturing process of composites for the reason that there are complicated processes during curing process of composites. The cure cycle has a significant effect on the quality of the finished part. The traditional cure cycle based on empirical approach could not ensure the quality of cured products because of unstabilized performance, high cost of production and low efficiency. As complex intelligent manufacturing systems are developed increasingly in industry, the necessity of more user friendly operation system is becoming progressively importance for their utilization and market value. This paper introduces some of the recent technological advances in the intelligent manufacturing systems that will influence the design and development of relevant industry.
基金supported by the National Natural Science Foundation of China(52071083,52231007,12327804,52471224)Zhuhai Fudan Innovation Institute,and the Science and Technology Commission of Shanghai Municipality(23ZR1405000).
文摘By the random distribution of metals in a single phase,entropy engineering is applied to construct dense neighboring active centers with diverse electronic and geometric structures,realizing the continuous optimization of multiple primary reactions for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).Many catalysts developed through entropy engineering have been built in nearly equimolar ratios to pursue high entropy,hindering the identification of the active sites and potentially diluting the concentration of real active sites while weakening their electronic interactions with reaction intermediates.Herein,this work proposes an entropy-engineering strategy in metal nanoparticle-embedded nitrogen carbon electrocatalysts,implemented by entropy-engineered Prussian blue analogs(PBA)as precursors to enhance the catalytic activity of primary Cu-Fe active sites.Through the introduction of the micro-strains driven by entropy engineering,density functional theory(DFT)calculations and geometric phase analysis(GPA)using Lorentz electron microscopy further elucidate the optimization of the adsorption/desorption of intermediates.Furthermore,the multi-dimensional morphology and the size diminishment of the nanocrystals serve to expand the electrochemical area,maximizing the catalytic activity for both ORR and OER.Notably,the Zn-air battery assembled with CuFeCoNiZn-NC operated for over 1300 h with negligible decay.This work presents a paradigm for the design of low-cost electrocatalysts with entropy engineering for multi-step reactions.
基金supported by the National Natural Science Foundation of China(51762014,52231007,12327804,T2321003,22088101)in part by the National Key Research Program of China under Grant 2021YFA1200600.
文摘Niobates are promising all-climate Li^(+)-storage anode material due to their fast charge transport,large specific capacities,and resistance to electrolyte reaction.However,their moderate unit-cellvolume expansion(generally 5%–10%)during Li^(+)storage causes unsatisfactory long-term cyclability.Here,“zero-strain”NiNb_(2)O_(6) fibers are explored as a new anode material with comprehensively good electrochemical properties.During Li^(+)storage,the expansion of electrochemical inactive NiO_(6) octahedra almost fully offsets the shrinkage of active NbO_(6) octahedra through reversible O movement.Such superior volume-accommodation capability of the NiO_(6) layers guarantees the“zero-strain”behavior of NiNb_(2)O_(6) in a broad temperature range(0.53%//0.51%//0.74%at 25//−10//60℃),leading to the excellent cyclability of the NiNb_(2)O_(6) fibers(92.8%//99.2%//91.1%capacity retention after 1000//2000//1000 cycles at 10C and 25//−10//60℃).This NiNb_(2)O_(6) material further exhibits a large reversible capacity(300//184//318 mAh g−1 at 0.1C and 25//−10//60℃)and outstanding rate performance(10 to 0.5C capacity percentage of 64.3%//50.0%//65.4%at 25//−10//60℃).Therefore,the NiNb_(2)O_(6) fibers are especially suitable for large-capacity,fast-charging,long-life,and all-climate lithium-ion batteries.
基金supported by grants from the National Key Research and Development Program(Grant Nos.2023YFC3806205).
文摘Purpose–This paper aims to analyze the transverse vibration characteristics of the high speed train window glass when passing through tunnel.Design/methodology/approach–The lateral vibration acceleration response of glass chamber of high-speed train CR400BF-A on Beijing-Chengdu high-speed railway was tested at different speeds through the tunnel entrance,exit,tunnel interior,Tunnel Group and rendezvous time in the tunnel,the lateral distribution characteristics of vibration frequency and vibration power amplification coefficient of glass of high-speed train were analyzed.Findings–The results show that:The vibration of the high-speed train glass increases significantly during the tunnel,and the amplitude of vibration acceleration in the tunnel is significantly higher than outside the tunnel as the travel speed increases;the amplitude of lateral vibration acceleration of the glass of a high-speed train does not vary with changes in tunnel length and is not affected by the aerodynamic effects of the tunnel when traveling inside the tunnel,but its vibrations create noticeable fluctuations during variations when encountering oncoming traffic;The vibration characteristics of the high-speed train glass are forced harmonic vibrations,the excitation frequency does not vary with travel speed and travel position changes inside and outside the tunnel.The lateral vibration acceleration of the glass of a high-speed train is applied vertically and uniformly to the glass surface as an“inertial force”and creates a cyclic bending vibration stress that can easily lead to fatigue damage.Originality/value–The research results provide guidance for the prevention of glass failure in high-speed trains.
基金supported by the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘Atomic-scale doping strategies and structure design play pivotal roles in tailoring the electronic structure and physicochemical property of electromagnetic wave absorption(EMWA)materials.However,the relationship between configuration and electromagnetic(EM)loss mechanism has remained elusive.Herein,drawing inspiration from the DNA transcription process,we report the successful synthesis of novel in situ Mn/N co-doped helical carbon nanotubes with ultrabroad EMWA capability.Theoretical calculation and EM simulation confirm that the orbital coupling and spin polarization of the Mn–N4–C configuration,along with cross polarization generated by the helical structure,endow the helical converters with enhanced EM loss.As a result,HMC-8 demonstrates outstanding EMWA performance,achieving a minimum reflection loss of−63.13 dB at an ultralow thickness of 1.29 mm.Through precise tuning of the graphite domain size,HMC-7 achieves an effective absorption bandwidth(EAB)of 6.08 GHz at 2.02 mm thickness.Furthermore,constructing macroscale gradient metamaterials enables an ultrabroadband EAB of 12.16 GHz at a thickness of only 5.00 mm,with the maximum radar cross section reduction value reaching 36.4 dB m2.This innovative approach not only advances the understanding of metal–nonmetal co-doping but also realizes broadband EMWA,thus contributing to the development of EMWA mechanisms and applications.
基金Funded by the National Natural Science Foundation of China(Nos.52072356 and 52032011)。
文摘The fracture behaviours and notch effects of single-edge-notched(SEN)and double-edge-notched(DEN)2D carbon fibre reinforced carbon matrix composites(C/Cs)were discussed and compared.The fracture behaviours of DEN and SEN were performed by tensile and bending load-displacement relationships,and the effects of notch depth on notch sensitivity were determined by DEN specimens.The results from mechanical tests indicated that the SEN exhibited a brittle behaviour with linear elasticity,while the DEN exhibited a ductile behaviour with nonlinearity.It was also found that increasing notch depth and decreasing ligament width can lead to a higher ultimate tensile strength of DEN.On the other hand,the digital image correlation(DIC)method and acoustic emission(AE)system were also applied during the mechanical tests to study the local mechanical characteristics of shear damage,strain concentration and fracture behaviour of 2D C/Cs.The results revealed the mechanisms of notch insensitivity and explained the differences in fracture behaviours between SEN and DEN.
基金Funded by the Zibo Key Research and Development Project(No.2020XCCG0106)the Zibo Key Research and Development Project(No.2021SNPT0004)the Opening Project of Glass-based Functional Material Technology Innovation Center(No.GFMTIC2025C01)。
文摘We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron generation and energy deposition,we found that 1.0 MeV electrons and protons produce 67.5 and 67 secondary electrons per particle,respectively,compared to 116 from 1.25 MeV gamma rays in thick targets.Boltzmann-function fitting revealed depth-dependent ionization equivalence:0.582 gamma photons match the secondary electron yield of a 1.0 MeV electron,and 0.577 gamma photons match a 1.0 MeV proton.These results establish a framework to convert ground-based gamma-ray test data to space environment scenarios,accounting for critical differences in penetration depth-protons deposit energy within 10μm(coating layers),while gamma rays penetrate>100 mm into substrates.This provides a theoretical basis for evaluating radiation effects using existing^(60)Co facilities,enabling reliable predictions of optical component durability in complex space environments.
基金Funded by Beijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z221100006722022)。
文摘We synthesized tungsten-doped vanadium dioxide(W-VO_(2))particles via a one-step hydrothermal method,followed by their integration with antimony-doped tin oxide(ATO)nanoparticles to formulate a composite coating.Subsequently,the VO_(2)/ATO composite coating was fabricated through a spin-coating process.The impact of varying W-VO_(2) content and coating thickness on the performance of the composite coatings was systematically investigated by employing X-ray diffraction,particle size distribution analysis,spectrometry,and other pertinent test methodologies.Our findings revealed that an escalation in both W-VO_(2) content and coating thickness retained high transmittance in the near-infrared band at lower temperatures.However,as the temperature increased,a notable reduction in transmittance in the near-infrared band was observed,alongside a slight decrease in transmittance within the visible band.Remarkably,when the W-VO_(2) content reached 5%and the coating thickness was 1253 nm,the transmittance of the composite coating surpassed 80%.Furthermore,the heat insulation effect achieved a remarkable 10.0℃increase.Consequently,the synthesized composite coating demonstrates significant potential for smart glass applications,particularly in the realm of heat-insulating glass.
基金Funded by the China Building Material Federation Projects(Nos.20221JBGS06-19,2023JBGS02-01)the National Natural Science Foundation of China(No.U2241236)。
文摘The viscosity of anti-irradiated glass was quantitatively characterized using beam bending viscometry(BBV),parallel plate viscometry(PPV),and rotational viscometry(RV).The Vogel-Fulcher-Tammann(VFT)equation was determined to be the most suitable for representing the viscosity-temperature characteristics of anti-irradiation glass by comparing the fitting effects and accuracy of different equations within different test ranges.The fragility index m of anti-irradiation glass was 47.5,as calculated using an Angell plot,and the cause of the appropriate fit of the VFT equation was analyzed.The effects of different heating temperatures and loading rates on the tensile properties of glass were studied using a universal testing machine.The results indicated that,at a tensile rate of 10 mm/s,the heating temperature increased from 903 to 1023 K,and the deformation process of anti-irradiation glass transitioned from unstable to stable.When the tensile rate increased from 10 to 30 mm/s at 1023 K,the deformation process of the glass was extremely unstable.This work provides theoretical guidance for the large-size preparation of flexible anti-irradiation glass.
基金supported by the National Key Research&Development Plan(No.2021YFA1600702)the National Natural Science Foundation of China(Nos.92263201,52301155,and 52001161).
文摘In this study,we developed an in-situ hot-pressing sintering(HPS)device that can be coupled to a lab-oratory X-ray microscope,offering laboratory-available observation of the morphology evolution.With the help of this device,in-situ three-dimensional(3D)visualizations of the microstructural evolution of 7055 aluminum alloys during the HPS process were conducted.The 3D results revealed that the twodimensional(2D)methods usually underestimated sintering neck width and exhibited significant standard deviation in statistical analysis.Benefiting from the precise microstructure characterization of the insitu 3D methods,the diffusion activation energy for the sintering of 7055 alloys was calculated,and the quantitative relationship between the sintering temperature and the sintering process was constructed.Moreover,it was experimentally found an accelerative effect of satellite particles on the sintering process,and its mechanisms were discussed.The satellite particles enhanced the curvature near the sintering neck and thus increased the sintering driving stress,promoting the densification process.These findings provide new insights for optimizing sintering processes.
