The use of solar energy to produce steam is an effective method to purify sewage or seawater. Herein, we deposited TiN nanoparticles(NPs) on a piece of carbonized wood as a new type of double layer material for solar ...The use of solar energy to produce steam is an effective method to purify sewage or seawater. Herein, we deposited TiN nanoparticles(NPs) on a piece of carbonized wood as a new type of double layer material for solar water evaporation. TiN NPs possess better stability, lower cost,lower toxicity and wider and stronger optical absorption than the previously reported photo-thermal conversion(PTC)materials, such as plasmonic metals, carbon-based materials and semiconductor nanomaterials. The amounts of TiN NPs and the thicknesses and types of the substrates have important influences on water evaporation rates and solar-vapor conversion efficiency. A solar-vapor conversion efficiency of 92.5%, the highest efficiency in the reported wood-based PTC materials, is obtained under 1-sun simulated solar irradiation.In addition, the TBCF hybrid materials(TiN NPs on biocarbon foam) exhibit good reusability.展开更多
Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the the...Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distributions in Nd：YVO4/YVO4 composite crystal and conventional crystal were analyzed and compared. The end-pumped Nd：YVO4/YVO4 composite crystal laser was designed and set up with z-cavity. The maximum output powers of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the incident pump power of 16.5 W. The highest optical-optical conversion efficiencies were up to 59.8% at 1064 nm and 37.2% at 532 nm respectively.展开更多
Conversion of CO2 into CO using plasma processing powered by renewable energy is a promising method to convert intermittent sustainable electricity into storable chemical energy.Despite extensive research efforts worl...Conversion of CO2 into CO using plasma processing powered by renewable energy is a promising method to convert intermittent sustainable electricity into storable chemical energy.Despite extensive research efforts worldwide,there is currently no process that achieves economically viable values for both CO2 conversion fraction and energy recovery efficiency simultaneously.Here we demonstrate that a process that utilizes the Boudouard reaction,CO^2++C→2 CO,driven by a thermal plasma allows both 95%CO2 conversion to CO and energy recovery efficiency of 70%,values far higher than seen so far.By comparing the conversion process with and without CO2 excitation by a plasma and by using optical emission spectroscopy we show that the improved performance is due to a novel mode of operation where CO2 is pyrolyzed into an active mixture of CO,O and O2 by an arc discharge which is then introduced into a fixed bed to interact with carbon material.In this way,the free oxygen in the mixture combusts with carbon to form CO,and residual plasma excited CO2 is reduced by carbon.In the overall process,the endothermic Boudouard reaction is partially replaced by an exothermic reaction,and the excess electric energy to produce CO2 plasma is reused in the carbon bed.展开更多
Increasing efficiency and reducing emissions are fundamental approaches to achieving peak carbon emissions and carbon neutrality for the transportation and power industries.The Argon power cycle(APC)is a novel concept...Increasing efficiency and reducing emissions are fundamental approaches to achieving peak carbon emissions and carbon neutrality for the transportation and power industries.The Argon power cycle(APC)is a novel concept for high efficiency and zero emissions.However,APC faces the challenges of severe knock and low power density at high efficiency.To elevate efficiency and power density simultaneously of APC,the Miller cycle is applied and combined with APC.The calculation method is based on a modification of the previous thermodynamic method.The mixture of hydrogen and oxygen is controlled in the stoichiometric ratio.The results indicate that to obtain a thermal conversion efficiency of 70%,in the Otto cycle,the compression ratio and the AR(argon molar ratio in the argon-oxygen mixture)could be 9 and 95%,respectively.In comparison,for the Miller cycle,these two parameters only need to be 7 and 91%.A lower compression ratio can reduce the negative effect of knock,and a reduced AR increases the power density by 66%with the same efficiency.The improvement effect is significant when the expansion-compression ratio is 1.5.Meanwhile,increasing the expansion-compression ratio is more effective in the argon-oxygen mixture than in the nitrogen–oxygen mixture.For the next-generation Argon/Miller power cycle engine,the feasible design to achieve the indicated thermal efficiency of 58.6%should be a compression ratio of 11,an expansion-compression ratio of 1.5,and an AR of 91%.展开更多
文摘The use of solar energy to produce steam is an effective method to purify sewage or seawater. Herein, we deposited TiN nanoparticles(NPs) on a piece of carbonized wood as a new type of double layer material for solar water evaporation. TiN NPs possess better stability, lower cost,lower toxicity and wider and stronger optical absorption than the previously reported photo-thermal conversion(PTC)materials, such as plasmonic metals, carbon-based materials and semiconductor nanomaterials. The amounts of TiN NPs and the thicknesses and types of the substrates have important influences on water evaporation rates and solar-vapor conversion efficiency. A solar-vapor conversion efficiency of 92.5%, the highest efficiency in the reported wood-based PTC materials, is obtained under 1-sun simulated solar irradiation.In addition, the TBCF hybrid materials(TiN NPs on biocarbon foam) exhibit good reusability.
基金This work was supported by the Science & Technology Research Fund of Shandong Province under Grant No. 031080125The authors would like to appreciate for the support from Science & Technology Board of Shandong Province.
文摘Thermal effect in crystals is the main obstacle blocking diode-pumped solid state laser to get high and stable output power. Diffusion bonding crystal has been demonstrated to be an effective method to relieve the thermal lensing theoretically based on the numerical heat analysis to the end-pumped anisotropic laser crystal. The temperature distributions in Nd：YVO4/YVO4 composite crystal and conventional crystal were analyzed and compared. The end-pumped Nd：YVO4/YVO4 composite crystal laser was designed and set up with z-cavity. The maximum output powers of 9.87 W at 1064 nm and 6.14 W at 532 nm were obtained at the incident pump power of 16.5 W. The highest optical-optical conversion efficiencies were up to 59.8% at 1064 nm and 37.2% at 532 nm respectively.
基金supported by the National Natural Science Foundation of China(Grants nos.11775155,51561135013,21603202)。
文摘Conversion of CO2 into CO using plasma processing powered by renewable energy is a promising method to convert intermittent sustainable electricity into storable chemical energy.Despite extensive research efforts worldwide,there is currently no process that achieves economically viable values for both CO2 conversion fraction and energy recovery efficiency simultaneously.Here we demonstrate that a process that utilizes the Boudouard reaction,CO^2++C→2 CO,driven by a thermal plasma allows both 95%CO2 conversion to CO and energy recovery efficiency of 70%,values far higher than seen so far.By comparing the conversion process with and without CO2 excitation by a plasma and by using optical emission spectroscopy we show that the improved performance is due to a novel mode of operation where CO2 is pyrolyzed into an active mixture of CO,O and O2 by an arc discharge which is then introduced into a fixed bed to interact with carbon material.In this way,the free oxygen in the mixture combusts with carbon to form CO,and residual plasma excited CO2 is reduced by carbon.In the overall process,the endothermic Boudouard reaction is partially replaced by an exothermic reaction,and the excess electric energy to produce CO2 plasma is reused in the carbon bed.
基金supported by the Natural Science Foundation of China(No.51576141)the Shanghai Science and Technology Program(No.22ZR1463000)。
文摘Increasing efficiency and reducing emissions are fundamental approaches to achieving peak carbon emissions and carbon neutrality for the transportation and power industries.The Argon power cycle(APC)is a novel concept for high efficiency and zero emissions.However,APC faces the challenges of severe knock and low power density at high efficiency.To elevate efficiency and power density simultaneously of APC,the Miller cycle is applied and combined with APC.The calculation method is based on a modification of the previous thermodynamic method.The mixture of hydrogen and oxygen is controlled in the stoichiometric ratio.The results indicate that to obtain a thermal conversion efficiency of 70%,in the Otto cycle,the compression ratio and the AR(argon molar ratio in the argon-oxygen mixture)could be 9 and 95%,respectively.In comparison,for the Miller cycle,these two parameters only need to be 7 and 91%.A lower compression ratio can reduce the negative effect of knock,and a reduced AR increases the power density by 66%with the same efficiency.The improvement effect is significant when the expansion-compression ratio is 1.5.Meanwhile,increasing the expansion-compression ratio is more effective in the argon-oxygen mixture than in the nitrogen–oxygen mixture.For the next-generation Argon/Miller power cycle engine,the feasible design to achieve the indicated thermal efficiency of 58.6%should be a compression ratio of 11,an expansion-compression ratio of 1.5,and an AR of 91%.
基金supported by the National Natural Science Foundation of China (22005293, U19A2092 and 22275180)the National Key Research and Development Program of China (2019YFA0405600)+1 种基金the Institute of Energy, Hefei Comprehensive National Science Center (21KZS212)the Collaborative Innovation Program of Hefei Science Center, CAS。
