Hydrous ruthenium oxide was formed by a new process. The precursor was obtained by mixing the aqueous solutions of RuCl3xH2O and NaHCO3. The addition of NaHCO3 led to the formation of an oxide with extremely fine RuO2...Hydrous ruthenium oxide was formed by a new process. The precursor was obtained by mixing the aqueous solutions of RuCl3xH2O and NaHCO3. The addition of NaHCO3 led to the formation of an oxide with extremely fine RuO2 particles forming a porous network structure in the oxide electrode. Polyethylene glycol was added as a controller to partly inhibit the sol-gel reaction. The rate capacitance of 530 F·g^-1 was measured for the powder formed at an optimal annealing temperature of 210℃. Several details concerning this new material, including crystal structure, particle size as a function of temperature, and electrochemical properties, were also reported. In addition, the rate capacitance of the composite electrode reached 800 F·g^-1 after carbon black was added. By using the modified electrode of a RuO2/carbon black composite electrode, the electrochemical capacitor exhibits high energy density and stable power characteristics. The values of specific energy and maximum specific power of 24 Wh·kg^-1 and 4 kW·kg^-1, respectively, are demonstrated for a cell voltage between 0 and 1 V.展开更多
The tunnel boring machine(TBM)is typically used in hard-rock tunnel excavation.Owing to the unsatisfactory adaptability of TBM to the surrounding rock,when crossing high-strength and high-wear strata,the TBM can easil...The tunnel boring machine(TBM)is typically used in hard-rock tunnel excavation.Owing to the unsatisfactory adaptability of TBM to the surrounding rock,when crossing high-strength and high-wear strata,the TBM can easily cause defects,such as abnormal wear on cutters and overload damage to bearings,thus affecting the construction efficiency and cost.Therefore,high-pressure waterjet technology should be applied to assist in rock breaking for efficient TBM tunneling.In this study,the effects of water pressure,nozzle diameter,and nozzle speed on cutting are investigated via laboratory experiments of cutting hard rock using high-pressure waterjets.The penetration performance of the TBM under different water pressures is investigated via a field industrial penetration test.The results show that high-pressure waterjets are highly efficient for rock breaking and are suitable for industrial applications,as they can accommodate the advancing speed of the TBM and achieve high-efficiency rock breaking.However,during the operation of high-pressure waterjets,the ambient temperature and waterjet temperature in the tunnel increase significantly,which weakens the cooling effect of the cutterhead and decreases the construction efficiency of the TBM.Therefore,temperature control and cooling measures for high-pressure waterjets during their long-term operation must be identified.This study provides a useful reference for the design and construction of high-pressure water-jet-assisted cutterheads for breaking road headers.展开更多
文摘Hydrous ruthenium oxide was formed by a new process. The precursor was obtained by mixing the aqueous solutions of RuCl3xH2O and NaHCO3. The addition of NaHCO3 led to the formation of an oxide with extremely fine RuO2 particles forming a porous network structure in the oxide electrode. Polyethylene glycol was added as a controller to partly inhibit the sol-gel reaction. The rate capacitance of 530 F·g^-1 was measured for the powder formed at an optimal annealing temperature of 210℃. Several details concerning this new material, including crystal structure, particle size as a function of temperature, and electrochemical properties, were also reported. In addition, the rate capacitance of the composite electrode reached 800 F·g^-1 after carbon black was added. By using the modified electrode of a RuO2/carbon black composite electrode, the electrochemical capacitor exhibits high energy density and stable power characteristics. The values of specific energy and maximum specific power of 24 Wh·kg^-1 and 4 kW·kg^-1, respectively, are demonstrated for a cell voltage between 0 and 1 V.
基金the National Natural Science Foundation of China (52204108)the Fundamental Research Funds for the Central Universities (300102251201).
文摘The tunnel boring machine(TBM)is typically used in hard-rock tunnel excavation.Owing to the unsatisfactory adaptability of TBM to the surrounding rock,when crossing high-strength and high-wear strata,the TBM can easily cause defects,such as abnormal wear on cutters and overload damage to bearings,thus affecting the construction efficiency and cost.Therefore,high-pressure waterjet technology should be applied to assist in rock breaking for efficient TBM tunneling.In this study,the effects of water pressure,nozzle diameter,and nozzle speed on cutting are investigated via laboratory experiments of cutting hard rock using high-pressure waterjets.The penetration performance of the TBM under different water pressures is investigated via a field industrial penetration test.The results show that high-pressure waterjets are highly efficient for rock breaking and are suitable for industrial applications,as they can accommodate the advancing speed of the TBM and achieve high-efficiency rock breaking.However,during the operation of high-pressure waterjets,the ambient temperature and waterjet temperature in the tunnel increase significantly,which weakens the cooling effect of the cutterhead and decreases the construction efficiency of the TBM.Therefore,temperature control and cooling measures for high-pressure waterjets during their long-term operation must be identified.This study provides a useful reference for the design and construction of high-pressure water-jet-assisted cutterheads for breaking road headers.
