AuPt nano particles are bi-functional catalysts for Oxygen Reduction Reaction （ORR） and Oxygen Evolution Reaction （OER） that were taken place on air electrodes in lithium air batteries. Magnetic field has been app...AuPt nano particles are bi-functional catalysts for Oxygen Reduction Reaction （ORR） and Oxygen Evolution Reaction （OER） that were taken place on air electrodes in lithium air batteries. Magnetic field has been applied during electrodeposition for the preparation of AuPt particles. With the increase of the magnetic flux density under constant current density, the grain size decreases from - 1μm to 200nm and the activity of the AuPt catalyst increases. The magnetic field oriented vertical to the electric field has a promotion effect on increasing the catalytic ability of AuPt/carbon electrode. By pulse plating, the grain size decreases to about 100nm. By adjusting parameters of the electric field and the magnetic field, controllable in-situ preparation of AuPt catalyst with various morphology and catalytic activity could be achieved.展开更多
An InP-based single-heterojunction bipolar transistor （SHBT） with base μ-bndge and emitter air-bridge is reported. Because those bridges reduce parasitic capacitance greatly, the cutoff frequency fT of the 2μm ...An InP-based single-heterojunction bipolar transistor （SHBT） with base μ-bndge and emitter air-bridge is reported. Because those bridges reduce parasitic capacitance greatly, the cutoff frequency fT of the 2μm ×12.5μm InP SHBT without de-embedding reaches 178GHz. It is critical in high-speed low power applications,such as OEIC receivers and analog-to-digital converters.展开更多
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this...Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.展开更多
Two interacting light filaments with different initial phases propagating in air are investigated numerically by using a ray tracing method. The evolution of the rays of a filament is governed by a potential field. Du...Two interacting light filaments with different initial phases propagating in air are investigated numerically by using a ray tracing method. The evolution of the rays of a filament is governed by a potential field. During propagation, the two potential wells of the two filaments can merge into one or repel each other, depending on the initial phase difference between the two filaments. The study provides a simple description of the interacting filaments.展开更多
Abstract Cathode catalysts comprising composite NiO, NiO-Pt, or LiNiO2 have been developed for electro- chemical oxidation of hydrogen sulfide in intermediate-temperature solid oxide fuel cells （ITSOFCs）. All cataly...Abstract Cathode catalysts comprising composite NiO, NiO-Pt, or LiNiO2 have been developed for electro- chemical oxidation of hydrogen sulfide in intermediate-temperature solid oxide fuel cells （ITSOFCs）. All catalysts exhibited good electrical conductivity and catalytic activity at operating temperature. Composite NiO catalysts were found to be more active and have lower over potential and higller current density than pure Pt although the electrical conductivity of NiO itself is lower than that of Pt. This problem has been overcome by either admixing as high as 10% （by mass）Ag powder into NiO_ cathode layer or using composite NiO c atalysts such as NiO-Pt and LiNiO2 catalysts. Composite catalysts like NiO with Ag, electrolyte and starch admixed, NiO-Pt, which was prepared from a mixture of NiO and Pt powders, by admixing electrolyte and starch, and LiNiO2, which is derived from the reaction of LiOH-H2O and NiO with electrolyte and starch admix_ed have been shown to be feasible and effective in an intermediate-temperature H2S-air fuel cell. A fuel cell using Li2SO4-based proton-conducting membrane as electrolyte, metal sulfides as anode catalysts, and composite NiO as cathode catalysts produced a maximum current density about 300mA·cm^-2 and maximum power density over 80 mW-cm-2 at 680℃.展开更多
An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the s...An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the specific surface area of the bare CoSnO3 nanoboxes(104.3 m2 g–1),the specific surface area of the CoSnO3@rGO nanocomposite increased to approximately 195.8 m2 g–1 and the electronic conductivity also improved.The increased specific surface area provided more space for the deposition of Li2O2,while the improved electronic conductivity accelerated the decomposition of Li2O2.Compared to bare CoSnO3,the overpotential reduced by approximately 20 and 60 mV at current densities of 100 and 500 mA g?1 when CoSnO3@rGO was used as the catalyst.A Li‐O2 battery using a CoSnO3@rGO nanocomposite as the cathode catalyst cycled indicated a superior cyclic stability of approximately 130 cycles at a current density of 200 mA g–1 with a limited capacity of 1000 mAh g–1,which is 25 cycles more than that of the bare amorphous CoSnO3 nanoboxes.展开更多
The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The resu...The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 anode.This was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-Mg.Combinative addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge voltage.However,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca anode.Consequently,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.展开更多
Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading form...Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading forms, and speed limits of the freight trains were studied. The result indicates that under wind environment： 1） As for vehicles without and with cross-loaded structure, aero-pressure on the former is bigger, but air velocity around the latter is larger; 2） When sideslip angle θ=0°, the airflow is symmetry about train vertical axis; when θ〉0°, the airflow is detached at the top of vehicles, and the air velocity increases above the separated line but decreases below it; 3） With θ increasing, the lateral force on the mid vehicle firstly increases but decreases as θ=75°; 4） When the 6-axis X2K fiat car loads empty boxes of a 40 ft and a 48 ft at 120 km/h, the overturning wind speed is 25.19 m/s, and the train should be stopped under the 12th grade wind speed.展开更多
The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the disc...The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the discharge plasma radiation from the different discharge gap regions in the gas pressure range （0.05-0.7 MPa） was established. It was shown that, the breakdown is occurred owing to the ionization wave, which starts from the electrode with small radius of curvature at both polarity of high voltage pulses. It is seen that formation of bright spots on the fiat electrode at the negative polarity of the electrode with small radius of curvature are observed during the changing of the discharge current polarity. It was shown that, at positive polarity of electrode with a small radius of curvature, the bright spots on the flat electrode arise due to the participation of the dynamic displacement current in the gap conductance.展开更多
Based on the Kubo formalism, the anomalous Hall effect in a magnetic two-dimensional hole gas with cubic-Rashba spin-orbit coupling is studied in the presence of δ-function scattering potential. When the weak, shortr...Based on the Kubo formalism, the anomalous Hall effect in a magnetic two-dimensional hole gas with cubic-Rashba spin-orbit coupling is studied in the presence of δ-function scattering potential. When the weak, shortranged disorder scattering is considered in the Born approximation, we find that the self-energy becomes diagonal in the helicity basis and its value is independent of the wave number, and the vertex correction to the anomalous Hall conductivity due to impurity scattering vanishes when both subbands are occupied. That is to say, the anomalous Hall effect is not vanishing or influenced by the vertex correction for two-dimensional heavy-hole system, which is in sharp contrast to the case of linear-Rashba spin-orbit coupling in the electron band when the short-range disorder scattering is considered and the extrinsic mechanism as well as the effect of external electric field on the SO interaction are ignored.展开更多
The aim of the research was to investigate black colored steel-tinplate use for absorber and covering material of the collector and compare the efficiency of three types of air heating collectors. This heated air can ...The aim of the research was to investigate black colored steel-tinplate use for absorber and covering material of the collector and compare the efficiency of three types of air heating collectors. This heated air can be exploited for drying of agricultural products, room ventilation and room heating etc. 0.1 × 0.5 × 1.0 meter long FPC （fiat-plate collector） with a sun following platform was built. Air velocity at the experiments was v = 0.9 m/s. Collectors of insulated and un-insulated surfaces with steel-tinplate absorber as a covering material warmed the ambient air up to 10-12 and 5-6 degrees correspondingly （at irradiance 800 W/m^2）. This difference indicates the great importance of insulating the collector body. It can be explained with intense heat exchange between the absorber and ambient air which reduces the efficiency of the collector. There was good correlation with irradiance and the air heating degree. The investigations showed that more effective FPC had the collector with absorber tinplate in the middle of the collector body. At favorable weather conditions the heating degree of the ambient air at the outlet reaches 6-8 degrees more that at the outlet of the insulated collector covered by steel-tinplate.展开更多
The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have dete...The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have determined some of the parame- ters of explosive properties of the one-component gases CH4, CO and C2H4 using an explosive trial device of polybasic explosive gas mixtures and emphasized particularly the effect on the limits of explosive concentration of the binary explosive mixed gases CH4＋CO, CH4＋C2H4, as a function of the amount of CO, C2H4 and inert flame resisting gases （N2, CO2）. The experimental results show that the effect of inert gases on the explosive limits of mixed gases, given the property of explosive gas, is obvious： the inert gases （N2, CO2） possess some inhibitory effects on the explosion of the multi-component explosive gas mixtures. The results will provide some experimental support to suppress the occurrence of the gas explosions in goaf areas and provide some directions for designing explosion-proof electric equipment and fire arresters.展开更多
Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention s...Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention since its first use as an anode in a battery. Its high specific energy （even better volumetric energy density than lithium） makes it ideal for many primary battery applications. However, the development of A1/Air cell with alkaline electrolyte has been lagged behind mainly due to the unfavorable parasitic hydrogen generation. Herein, we designed and constructed a novel A1/H_2/Air tandem fuel cell to turn the adverse parasitic reaction into a useful process. The system consists of two anodes, namely, aluminum and hydrogen, and one common air-breathing cathode. The aluminum acts as both the anode for the A1/Air sub-cell and the source to generate hydrogen for the hydrogen/air sub-cell. The aluminum/air sub-cell has an open circuit voltage of 1.45 V and the H_2/Air sub-cell of 0.95 V. We demonstrated that the maximum power output of aluminum as a fuel was largely enhanced by 31% after incorporating the H_2/Air sub-cell with the tandem concept. In addition, a passive design was utilized in our tandem system to eliminate the dependence on auxiliary pumping sub-systems so that the whole system remained neat and eliminated the dependence of energy consuming pumps or heaters which were typically applied in micro fuel cells.展开更多
基金This work was supported by the National Natural Science Foundation of China （No.51304056）, the China Postdoctoral Science Foundation （No.2013M531049）, the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, and the Fundamental Research Funds for the Central Universities （No.HIT.NSRIF.2011021）.
文摘AuPt nano particles are bi-functional catalysts for Oxygen Reduction Reaction （ORR） and Oxygen Evolution Reaction （OER） that were taken place on air electrodes in lithium air batteries. Magnetic field has been applied during electrodeposition for the preparation of AuPt particles. With the increase of the magnetic flux density under constant current density, the grain size decreases from - 1μm to 200nm and the activity of the AuPt catalyst increases. The magnetic field oriented vertical to the electric field has a promotion effect on increasing the catalytic ability of AuPt/carbon electrode. By pulse plating, the grain size decreases to about 100nm. By adjusting parameters of the electric field and the magnetic field, controllable in-situ preparation of AuPt catalyst with various morphology and catalytic activity could be achieved.
文摘An InP-based single-heterojunction bipolar transistor （SHBT） with base μ-bndge and emitter air-bridge is reported. Because those bridges reduce parasitic capacitance greatly, the cutoff frequency fT of the 2μm ×12.5μm InP SHBT without de-embedding reaches 178GHz. It is critical in high-speed low power applications,such as OEIC receivers and analog-to-digital converters.
基金Projects(51504212,21573184,51703061)supported by the National Natural Science Foundation of ChinaProject(2018J01521)supported by the Natural Science Foundation of Fujian Province,ChinaProject(fma2017202)supported by the Open Fund of Fujian Provincial Key Laboratory of Functional Materials and Applications(Xiamen University of Technology),China
文摘Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review.Various fabrication methods of these oxides are introduced in detail,and their advantages and disadvantages are analyzed.Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides.As a bifunctional electrocatalyst,perovskite-type oxides are widely used in rechargeable metal-air batteries.The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized.This work is concentrated on the structural stability,the phase compositions,and catalytic performance of perovskite-type oxides in oxygen/air electrodes.The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60621063, 10334110, 10425416, 10634020 and 60478047）, the National Key Basic Research Special Foundation of China （Grant No G1999075206）, and the National Hi-Tech ICF Programme.
文摘Two interacting light filaments with different initial phases propagating in air are investigated numerically by using a ray tracing method. The evolution of the rays of a filament is governed by a potential field. During propagation, the two potential wells of the two filaments can merge into one or repel each other, depending on the initial phase difference between the two filaments. The study provides a simple description of the interacting filaments.
基金Supported by the Natural Science Foundation of Guangdong Province （No.05006552）.
文摘Abstract Cathode catalysts comprising composite NiO, NiO-Pt, or LiNiO2 have been developed for electro- chemical oxidation of hydrogen sulfide in intermediate-temperature solid oxide fuel cells （ITSOFCs）. All catalysts exhibited good electrical conductivity and catalytic activity at operating temperature. Composite NiO catalysts were found to be more active and have lower over potential and higller current density than pure Pt although the electrical conductivity of NiO itself is lower than that of Pt. This problem has been overcome by either admixing as high as 10% （by mass）Ag powder into NiO_ cathode layer or using composite NiO c atalysts such as NiO-Pt and LiNiO2 catalysts. Composite catalysts like NiO with Ag, electrolyte and starch admixed, NiO-Pt, which was prepared from a mixture of NiO and Pt powders, by admixing electrolyte and starch, and LiNiO2, which is derived from the reaction of LiOH-H2O and NiO with electrolyte and starch admix_ed have been shown to be feasible and effective in an intermediate-temperature H2S-air fuel cell. A fuel cell using Li2SO4-based proton-conducting membrane as electrolyte, metal sulfides as anode catalysts, and composite NiO as cathode catalysts produced a maximum current density about 300mA·cm^-2 and maximum power density over 80 mW-cm-2 at 680℃.
基金supported by the National Natural Science Foundation of China (11405144)the Fundamental Research Funds for the Central Universities (20720180081)~~
文摘An amorphous CoSnO3@rGO nanocomposite fabricated using a surfactant‐assisted assembly method combined with thermal treatment served as a catalyst for non‐aqueous lithium‐oxygen(Li‐O2)batteries.In contrast to the specific surface area of the bare CoSnO3 nanoboxes(104.3 m2 g–1),the specific surface area of the CoSnO3@rGO nanocomposite increased to approximately 195.8 m2 g–1 and the electronic conductivity also improved.The increased specific surface area provided more space for the deposition of Li2O2,while the improved electronic conductivity accelerated the decomposition of Li2O2.Compared to bare CoSnO3,the overpotential reduced by approximately 20 and 60 mV at current densities of 100 and 500 mA g?1 when CoSnO3@rGO was used as the catalyst.A Li‐O2 battery using a CoSnO3@rGO nanocomposite as the cathode catalyst cycled indicated a superior cyclic stability of approximately 130 cycles at a current density of 200 mA g–1 with a limited capacity of 1000 mAh g–1,which is 25 cycles more than that of the bare amorphous CoSnO3 nanoboxes.
基金financial supports from the Key Development Project of Sichuan Province,China (No.2017GZ0399)the National Natural Science Foundation of China (No.52061040)the Open Projects of the Key Laboratory of Advanced Technologies of Materials,Ministry of Education,Southwest Jiaotong University,China (No.KLATM202003)。
文摘The effects of yttrium(Y)and yttrium+calcium(Y+Ca)additions on the electrochemical properties and discharge performance of the as-extruded Mg−8Al−0.5Zn−0.2Mn(AZ80)anodes for Mg−air batteries were investigated.The results show that the addition of 0.2 wt.%Y increased the corrosion resistance and discharge activity of AZ80 anode.This was attributed to the fine and sphericalβ-Mg_17)Al_(12) phases dispersing evenly in AZ80+0.2Y alloy,which suppressed the localized corrosion and severe“chunk effect”,and facilitated the rapid activation ofα-Mg.Combinative addition of 0.2 wt.%Y and 0.15 wt.%Ca generated grain refinement and a reduction of theβ-Mg_17)Al_(12) phase,resulting in a further enhancement in discharge voltage.However,the incorporation of Ca in Mg_17)Al_(12) and Al_(2)Y compounds compromised the corrosion resistance and anodic efficiency of AZ80+0.2Y+0.15Ca anode.Consequently,AZ80+0.2Y anode exhibited excellent overall discharge performance,with the peak discharge capacity and anodic efficiency of 1525 mA·h·g^(−1) and 67%at 80 mA/cm^(2),13%and 14%higher than those of AZ80 anode,respectively.
基金Project supported by Scholarship Award for Excellent Doctoral Student granted by Ministry of Education,ChinaProject(2012QNZT029) supported by the Fundamental Research Funds for the Central Universities of China+1 种基金Project(CX2010B122) supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2010ybfz088) supported by the Foundation of Excellent Doctoral Dissertation of Central South University,China
文摘Based on 3D, steady N-S equations and k-e turbulence model, Fluent was employed to do numerical simulation for lateral aerodynamic performance of 6-axis X2K double-deck container trains with two different loading forms, and speed limits of the freight trains were studied. The result indicates that under wind environment： 1） As for vehicles without and with cross-loaded structure, aero-pressure on the former is bigger, but air velocity around the latter is larger; 2） When sideslip angle θ=0°, the airflow is symmetry about train vertical axis; when θ〉0°, the airflow is detached at the top of vehicles, and the air velocity increases above the separated line but decreases below it; 3） With θ increasing, the lateral force on the mid vehicle firstly increases but decreases as θ=75°; 4） When the 6-axis X2K fiat car loads empty boxes of a 40 ft and a 48 ft at 120 km/h, the overturning wind speed is 25.19 m/s, and the train should be stopped under the 12th grade wind speed.
基金Acknowledgments The work was supported by the grant from the Russian Science Foundation, project No. 14-29-00052.
文摘The formation of runaway electron pre-ionized diffuse discharges at the pressures 0.05-0.7 MPa of in air, argon, nitrogen, and SF6 in an inhomogeneous electric field was investigated. Dynamics of intensity of the discharge plasma radiation from the different discharge gap regions in the gas pressure range （0.05-0.7 MPa） was established. It was shown that, the breakdown is occurred owing to the ionization wave, which starts from the electrode with small radius of curvature at both polarity of high voltage pulses. It is seen that formation of bright spots on the fiat electrode at the negative polarity of the electrode with small radius of curvature are observed during the changing of the discharge current polarity. It was shown that, at positive polarity of electrode with a small radius of curvature, the bright spots on the flat electrode arise due to the participation of the dynamic displacement current in the gap conductance.
基金Supported by the Research Fund for Outstanding Young Teachers in Higher Education Institutions of Shanghai under Grant No.gjd08040the Scientific Research Startup Funds of SUESthe National Natural Science Foundation of China under Grant No.C-6201-10-001
文摘Based on the Kubo formalism, the anomalous Hall effect in a magnetic two-dimensional hole gas with cubic-Rashba spin-orbit coupling is studied in the presence of δ-function scattering potential. When the weak, shortranged disorder scattering is considered in the Born approximation, we find that the self-energy becomes diagonal in the helicity basis and its value is independent of the wave number, and the vertex correction to the anomalous Hall conductivity due to impurity scattering vanishes when both subbands are occupied. That is to say, the anomalous Hall effect is not vanishing or influenced by the vertex correction for two-dimensional heavy-hole system, which is in sharp contrast to the case of linear-Rashba spin-orbit coupling in the electron band when the short-range disorder scattering is considered and the extrinsic mechanism as well as the effect of external electric field on the SO interaction are ignored.
文摘The aim of the research was to investigate black colored steel-tinplate use for absorber and covering material of the collector and compare the efficiency of three types of air heating collectors. This heated air can be exploited for drying of agricultural products, room ventilation and room heating etc. 0.1 × 0.5 × 1.0 meter long FPC （fiat-plate collector） with a sun following platform was built. Air velocity at the experiments was v = 0.9 m/s. Collectors of insulated and un-insulated surfaces with steel-tinplate absorber as a covering material warmed the ambient air up to 10-12 and 5-6 degrees correspondingly （at irradiance 800 W/m^2）. This difference indicates the great importance of insulating the collector body. It can be explained with intense heat exchange between the absorber and ambient air which reduces the efficiency of the collector. There was good correlation with irradiance and the air heating degree. The investigations showed that more effective FPC had the collector with absorber tinplate in the middle of the collector body. At favorable weather conditions the heating degree of the ambient air at the outlet reaches 6-8 degrees more that at the outlet of the insulated collector covered by steel-tinplate.
基金The financial supports from the National Natural Science Foundation of China (No.50874088)the Changjiang Scholars and Innovative Research Team in University (No.IRT0856)
文摘The explosive gases CO and C2H4, released mainly flammable gases during the process of coal self-ignition, are of the most important ingredients of the multi-component gases in goal areas, along with CH4. We have determined some of the parame- ters of explosive properties of the one-component gases CH4, CO and C2H4 using an explosive trial device of polybasic explosive gas mixtures and emphasized particularly the effect on the limits of explosive concentration of the binary explosive mixed gases CH4＋CO, CH4＋C2H4, as a function of the amount of CO, C2H4 and inert flame resisting gases （N2, CO2）. The experimental results show that the effect of inert gases on the explosive limits of mixed gases, given the property of explosive gas, is obvious： the inert gases （N2, CO2） possess some inhibitory effects on the explosion of the multi-component explosive gas mixtures. The results will provide some experimental support to suppress the occurrence of the gas explosions in goaf areas and provide some directions for designing explosion-proof electric equipment and fire arresters.
文摘Metal/Air batteries are considered to be promising electricity storage devices given their compactness, environmental benignity and affordability. As a commonly available metal, aluminum has received great attention since its first use as an anode in a battery. Its high specific energy （even better volumetric energy density than lithium） makes it ideal for many primary battery applications. However, the development of A1/Air cell with alkaline electrolyte has been lagged behind mainly due to the unfavorable parasitic hydrogen generation. Herein, we designed and constructed a novel A1/H_2/Air tandem fuel cell to turn the adverse parasitic reaction into a useful process. The system consists of two anodes, namely, aluminum and hydrogen, and one common air-breathing cathode. The aluminum acts as both the anode for the A1/Air sub-cell and the source to generate hydrogen for the hydrogen/air sub-cell. The aluminum/air sub-cell has an open circuit voltage of 1.45 V and the H_2/Air sub-cell of 0.95 V. We demonstrated that the maximum power output of aluminum as a fuel was largely enhanced by 31% after incorporating the H_2/Air sub-cell with the tandem concept. In addition, a passive design was utilized in our tandem system to eliminate the dependence on auxiliary pumping sub-systems so that the whole system remained neat and eliminated the dependence of energy consuming pumps or heaters which were typically applied in micro fuel cells.
