Alumina-magnesia dry materials are widely used in induction furnace linings, but they show different kinds of damage when melting different kinds of alloy steel. In this paper, the chemical composition, phase composit...Alumina-magnesia dry materials are widely used in induction furnace linings, but they show different kinds of damage when melting different kinds of alloy steel. In this paper, the chemical composition, phase composition, and microstructure of the post-use dry materials for the working liners melting different kinds of steel were evaluated. Furthermore, the corrosion mechanism of the steel on the furnace lining materials was comprehensively analyzed. The findings reveal a significant ability of the Mn element in the molten steel to diffuse and penetrate into the refractories. Mn oxidizes to form MnO at the steel-refractory interface, and then forms a liquid phase with Al_(2)O_(3). The Cr element is dissolved into corundum and spinel of the refractories, resulting in lattice defects and structural damage of the materials. TiO2reacts with Al_(2)O_(3) to form Al_(2)TiO_(5), which plays a crucial role in preventing crack formation and propagation. Part of Ti4+dissolves into magnesia-alumina(MA), densifying the materials. TiO2also slows down the reaction between the Cr element and refractory components, further improving the corrosion resistance of the materials.展开更多
In order to predict the flattening rate of the cross-section accurately during the tube ben- ding, the generation principle, the solution and the influence factor of the cross-section flattening were studied. On the b...In order to predict the flattening rate of the cross-section accurately during the tube ben- ding, the generation principle, the solution and the influence factor of the cross-section flattening were studied. On the basis of the plane-stress and the assumption that the plastic volume is con- stant, three-dimensionai strain formulas were established in consider of the cross-section flattening. Considering the wail-thickness change, the approximate calculation formulas of short axis flattening rate were deduced, with the outer diameter and the inner diameter as parameters. Because different materials have different cross-section flattening rates, a material correction factor was introduced to modify the formula based on experiments. Finally, the validity of the theoretical formulas was proved according to the calculation and the experiment results, which can provide a reference for the forming quality prediction in tube bending.展开更多
The static characteristics of an axial-flux permanentmagnet( AFPM) machine with coreless stator were investigated.Two-dimensional analytical method for prediction of the no-load magnetic field in the AFPM machine with...The static characteristics of an axial-flux permanentmagnet( AFPM) machine with coreless stator were investigated.Two-dimensional analytical method for prediction of the no-load magnetic field in the AFPM machine with coreless stator was derived. Electromotive force( EMF) and axial attraction force were deduced from the analytical method. These values obtained from analytical method were compared with those from finite element method( FEM) and agree well. Finally,a prototype was built for experimental validation and back EMF was measured. The results confirmed the validity of the proposed analytical method.展开更多
A multimode interference refractive index （KI） sensor based on the coreless fiber was numerically and experimentally demonstrated. Two identical single mode fibers （SMF） are spliced at both ends of a section of th...A multimode interference refractive index （KI） sensor based on the coreless fiber was numerically and experimentally demonstrated. Two identical single mode fibers （SMF） are spliced at both ends of a section of the coreless fiber which can he considered as the equivalent weakly guiding multimode fiber （MMF） with a step-index profile when the surrounding refractive index （SKI） is lower than that of the coreless fiber. Thus, it becomes the conventional single-mode multimode single-mode （SMS） fiber structure but with a larger core size. The output spectra will shift along with the changes in the SKI owing to the direct exposure of the coreless fiber. The output spectra under different SKIs were numerically studied, as well as the sensitivities with different lengths and diameters of the coreless fiber. The predication and calculation showed the good agreement with the experimental results. The proposed RI sensor proved to be feasible by verification experiments, and the relative error was merely 0.1% which occupied preferable sensing performance and practicability.展开更多
Bimetallic nanocluster with atomic precision has gained widespread attention due to its unique synergism.The coreless Au_(4)Cu_(5)bimetallic nanoclusters were selected as models to explore the relationship between the...Bimetallic nanocluster with atomic precision has gained widespread attention due to its unique synergism.The coreless Au_(4)Cu_(5)bimetallic nanoclusters were selected as models to explore the relationship between their microstructure and performance,and compare with the coreless monometallic nanoclusters,core–shell nanoclusters,and single atom catalyst(SAC).The experimental results show that the coreless bimetallic nanocluster catalyst Au_(4)Cu_(5)/activated carbon(AC)exhibits high activity and stability in the Ullmann C–O coupling reaction,much higher than coreless monometallic nanoclusters(Au_(11)/AC and Cu_(11)/AC),core–shell nanoclusters(Au_(25)/AC,Cu_(25)/AC,and Au_(1)Cu_(24)/AC),and single atom catalysts(Au SAC and Cu SAC).Moreover,the coreless Au_(4)Cu_(5)/AC catalyst efficiently catalyzed the Ullmann C–O coupling of benzyl alcohol for the first time.This structure–activity relationship was successfully extended to other coreless bimetallic systems,such as Au_(4)Cu_(4)/AC nanocluster,and it is expected to provide new insights for the design of bimetallic catalysts with well-defined performance.展开更多
基金the National Natural Science Foundation of China(52272022)Key Program of Natural Science Foundation of Hubei Province(2021CFA071).
文摘Alumina-magnesia dry materials are widely used in induction furnace linings, but they show different kinds of damage when melting different kinds of alloy steel. In this paper, the chemical composition, phase composition, and microstructure of the post-use dry materials for the working liners melting different kinds of steel were evaluated. Furthermore, the corrosion mechanism of the steel on the furnace lining materials was comprehensively analyzed. The findings reveal a significant ability of the Mn element in the molten steel to diffuse and penetrate into the refractories. Mn oxidizes to form MnO at the steel-refractory interface, and then forms a liquid phase with Al_(2)O_(3). The Cr element is dissolved into corundum and spinel of the refractories, resulting in lattice defects and structural damage of the materials. TiO2reacts with Al_(2)O_(3) to form Al_(2)TiO_(5), which plays a crucial role in preventing crack formation and propagation. Part of Ti4+dissolves into magnesia-alumina(MA), densifying the materials. TiO2also slows down the reaction between the Cr element and refractory components, further improving the corrosion resistance of the materials.
基金Supported by the National Natural Science Foundation of China(50805009)Twelve Five-Year Plan Basic Research Item of National Defense of China(A2220110008)
文摘In order to predict the flattening rate of the cross-section accurately during the tube ben- ding, the generation principle, the solution and the influence factor of the cross-section flattening were studied. On the basis of the plane-stress and the assumption that the plastic volume is con- stant, three-dimensionai strain formulas were established in consider of the cross-section flattening. Considering the wail-thickness change, the approximate calculation formulas of short axis flattening rate were deduced, with the outer diameter and the inner diameter as parameters. Because different materials have different cross-section flattening rates, a material correction factor was introduced to modify the formula based on experiments. Finally, the validity of the theoretical formulas was proved according to the calculation and the experiment results, which can provide a reference for the forming quality prediction in tube bending.
基金National Natural Science Foundation of China(No.51207072)
文摘The static characteristics of an axial-flux permanentmagnet( AFPM) machine with coreless stator were investigated.Two-dimensional analytical method for prediction of the no-load magnetic field in the AFPM machine with coreless stator was derived. Electromotive force( EMF) and axial attraction force were deduced from the analytical method. These values obtained from analytical method were compared with those from finite element method( FEM) and agree well. Finally,a prototype was built for experimental validation and back EMF was measured. The results confirmed the validity of the proposed analytical method.
文摘A multimode interference refractive index （KI） sensor based on the coreless fiber was numerically and experimentally demonstrated. Two identical single mode fibers （SMF） are spliced at both ends of a section of the coreless fiber which can he considered as the equivalent weakly guiding multimode fiber （MMF） with a step-index profile when the surrounding refractive index （SKI） is lower than that of the coreless fiber. Thus, it becomes the conventional single-mode multimode single-mode （SMS） fiber structure but with a larger core size. The output spectra will shift along with the changes in the SKI owing to the direct exposure of the coreless fiber. The output spectra under different SKIs were numerically studied, as well as the sensitivities with different lengths and diameters of the coreless fiber. The predication and calculation showed the good agreement with the experimental results. The proposed RI sensor proved to be feasible by verification experiments, and the relative error was merely 0.1% which occupied preferable sensing performance and practicability.
基金We acknowledge financial support by the National Natural Science Foundation of China(Nos.21972001 and 21871001)Natural Science Foundation of Anhui Province(No.2008085MB37)Anhui University.
文摘Bimetallic nanocluster with atomic precision has gained widespread attention due to its unique synergism.The coreless Au_(4)Cu_(5)bimetallic nanoclusters were selected as models to explore the relationship between their microstructure and performance,and compare with the coreless monometallic nanoclusters,core–shell nanoclusters,and single atom catalyst(SAC).The experimental results show that the coreless bimetallic nanocluster catalyst Au_(4)Cu_(5)/activated carbon(AC)exhibits high activity and stability in the Ullmann C–O coupling reaction,much higher than coreless monometallic nanoclusters(Au_(11)/AC and Cu_(11)/AC),core–shell nanoclusters(Au_(25)/AC,Cu_(25)/AC,and Au_(1)Cu_(24)/AC),and single atom catalysts(Au SAC and Cu SAC).Moreover,the coreless Au_(4)Cu_(5)/AC catalyst efficiently catalyzed the Ullmann C–O coupling of benzyl alcohol for the first time.This structure–activity relationship was successfully extended to other coreless bimetallic systems,such as Au_(4)Cu_(4)/AC nanocluster,and it is expected to provide new insights for the design of bimetallic catalysts with well-defined performance.
