The effect of magnesia on calcium ferrite(CaO.Fe2O3)reduction by CO was examined by isothermal thermogravimetry.Samples of calcium ferrite added with 0,2,4,and 8 wt.%magnesia(abbreviated as CF,CF2M,CF4M,and CF8M)were ...The effect of magnesia on calcium ferrite(CaO.Fe2O3)reduction by CO was examined by isothermal thermogravimetry.Samples of calcium ferrite added with 0,2,4,and 8 wt.%magnesia(abbreviated as CF,CF2M,CF4M,and CF8M)were prepared.Phase composition was analyzed by X-ray diffraction,and the results indicated that CF2M and CF4M are reduced to lower reduction degree and with lower apparent activation energy than CF;and CF8M with more MgO.Fe2O3 is reduced to a lower degree and with more difficulty compared with CF.Reduction rate analysis revealed that CF,CF2M,CF4M,and CF8M reductions are all typical two-step reactions with the order of CF→CWF(CaO.FeO.Fe2O3)→Fe.The apparent reduction activation energies of CF,CF2M,CF4M,and CF8M are 46.89,37.30,17.30,and 29.20 kJ/mol,respectively.Sharp analysis depicted that CF2M,CF4M,and CF8M reductions are all described by 2D Avrami–Erofeev(A–E)equation(A2)in the whole process,while CF reduction is first expressed by A2 and then by 3D A–E equation(A3).Different from shrinking core model,a new kinetic model for powdery samples reduction was proposed to illustrate the relationship among reduction rates,reduction routes,and model functions.展开更多
Unconventional superconductivity,in particular,in noncentrosymmetric systems,has been a long-sought topic in condensed matter physics.Recently,Re-based superconductors have attracted great attention owing to the poten...Unconventional superconductivity,in particular,in noncentrosymmetric systems,has been a long-sought topic in condensed matter physics.Recently,Re-based superconductors have attracted great attention owing to the potential time-reversal symmetry breaking in their superconducting states.We report the superconducting properties of noncentrosymmetric compounds Ta_(x)Re_(1-x) with 0.1 ≤x≤0.25,and find that the superconducting transition temperature reaches a maximum of ~8 K at the optimal level x=0.15.Nevertheless,muon-spin rotation and relaxation measurements reveal no time-reversal symmetry breaking existing in its superconducting state,which is in sharp contrast to both centrosymmetric Re metal and many other noncentrosymmetric Re-based superconductors.展开更多
Computed tomography(CT)generates cross-sectional images of the body.Visualizing CT images has been a challenging problem.The emergence of the augmented and virtual reality technology has provided promising solutions.H...Computed tomography(CT)generates cross-sectional images of the body.Visualizing CT images has been a challenging problem.The emergence of the augmented and virtual reality technology has provided promising solutions.However,existing solutions suffer from tethered display or wireless transmission latency.In this paper,we present ARSlice,a proof-of-concept prototype that can visualize CT images in an untethered manner without wireless transmission latency.Our ARSlice prototype consists of two parts,the user end and the projector end.By employing dynamic tracking and projection,the projector end can track the user-end equipment and project CT images onto it in real time.The user-end equipment is responsible for displaying these CT images into the 3D space.Its main feature is that the user-end equipment is a pure optical device with light weight,low cost,and no energy consumption.Our experiments demonstrate that our ARSlice prototype provides part of six degrees of freedom for the user,and a high frame rate.By interactively visualizing CT images into the 3D space,our ARSlice prototype can help untrained users better understand that CT images are slices of a body.展开更多
基金supported by the National Natural Science Foundation of China (No. U2033204)Engineering Laboratory of Battery Safety and Accident Control of Petroleum and Chemical Industry, China (No. ELBSAC202304)supported by Youth Innovation Promotion Association, Chinese Academy of Sciences (No. Y201768)
基金the financial support of the National Natural Science Foundation of China(51234010 and 51522403)the Program for New Century Excellent Talents in University and the Program for the Youth Top-Notch Talents of Chongqing(20151001)Ultrasonic Assisted Iron Ore Sintering Technology Research(cstc2014kjrc-qnrc90001),and China Scholarship Council.
文摘The effect of magnesia on calcium ferrite(CaO.Fe2O3)reduction by CO was examined by isothermal thermogravimetry.Samples of calcium ferrite added with 0,2,4,and 8 wt.%magnesia(abbreviated as CF,CF2M,CF4M,and CF8M)were prepared.Phase composition was analyzed by X-ray diffraction,and the results indicated that CF2M and CF4M are reduced to lower reduction degree and with lower apparent activation energy than CF;and CF8M with more MgO.Fe2O3 is reduced to a lower degree and with more difficulty compared with CF.Reduction rate analysis revealed that CF,CF2M,CF4M,and CF8M reductions are all typical two-step reactions with the order of CF→CWF(CaO.FeO.Fe2O3)→Fe.The apparent reduction activation energies of CF,CF2M,CF4M,and CF8M are 46.89,37.30,17.30,and 29.20 kJ/mol,respectively.Sharp analysis depicted that CF2M,CF4M,and CF8M reductions are all described by 2D Avrami–Erofeev(A–E)equation(A2)in the whole process,while CF reduction is first expressed by A2 and then by 3D A–E equation(A3).Different from shrinking core model,a new kinetic model for powdery samples reduction was proposed to illustrate the relationship among reduction rates,reduction routes,and model functions.
基金Supported by the National Key R&D Program of China(Grant No.2018YFA0704300)the National Natural Science Foundation of China(Grant Nos.U1732162,11974061,11704047,U1832147 and 11674054)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB25000000)。
文摘Unconventional superconductivity,in particular,in noncentrosymmetric systems,has been a long-sought topic in condensed matter physics.Recently,Re-based superconductors have attracted great attention owing to the potential time-reversal symmetry breaking in their superconducting states.We report the superconducting properties of noncentrosymmetric compounds Ta_(x)Re_(1-x) with 0.1 ≤x≤0.25,and find that the superconducting transition temperature reaches a maximum of ~8 K at the optimal level x=0.15.Nevertheless,muon-spin rotation and relaxation measurements reveal no time-reversal symmetry breaking existing in its superconducting state,which is in sharp contrast to both centrosymmetric Re metal and many other noncentrosymmetric Re-based superconductors.
基金the National Natural Science Foundation of China under Grant No.61872210the Guangdong Basic and Applied Basic Research Foundation under Grant Nos.2021A1515012596 and 2021B1515120064the Guangdong Academy of Sciences Special Foundation under Grant No.2021GDASYL-20210102006.
文摘Computed tomography(CT)generates cross-sectional images of the body.Visualizing CT images has been a challenging problem.The emergence of the augmented and virtual reality technology has provided promising solutions.However,existing solutions suffer from tethered display or wireless transmission latency.In this paper,we present ARSlice,a proof-of-concept prototype that can visualize CT images in an untethered manner without wireless transmission latency.Our ARSlice prototype consists of two parts,the user end and the projector end.By employing dynamic tracking and projection,the projector end can track the user-end equipment and project CT images onto it in real time.The user-end equipment is responsible for displaying these CT images into the 3D space.Its main feature is that the user-end equipment is a pure optical device with light weight,low cost,and no energy consumption.Our experiments demonstrate that our ARSlice prototype provides part of six degrees of freedom for the user,and a high frame rate.By interactively visualizing CT images into the 3D space,our ARSlice prototype can help untrained users better understand that CT images are slices of a body.
