Realizing all-day and all-weather energy-saving heating is crucial for mitigating the global energy and ecology crisis.Electric/solar heating are two promising heating approaches,yet materials with high elec-trical co...Realizing all-day and all-weather energy-saving heating is crucial for mitigating the global energy and ecology crisis.Electric/solar heating are two promising heating approaches,yet materials with high elec-trical conductivity,high solar absorptivity,and low infrared emissivity at the same time are rare in na-ture,which are highly anticipated and of great significance for highly efficient electric/solar heating.In this work,we demonstrate that Ti_(3)C_(2)T_(x) MXene with low IR emissivity(14.5%)fills the gap in the absence of the above materials,exhibiting a remarkable electric/solar heating performance.The saturated heating temperature of Ti_(3)C_(2)T_(x) film reaches a record-high value of 201°C at a low driving voltage of 1.5 V,and reaches 84.3°C under practical solar irradiation(750 W/m^(2))with a high solar to the thermal conversion efficiency of 75.3%,which is far superior to other reported materials.Meanwhile,the low IR emissivity endows Ti_(3)C_(2)T_(x) with a remarkable passive radiative heating capability of 7.0°C,ensuring zero-energy heating without electric/solar energy supply.The intrinsic characteristic of high electrical conductivity,high solar absorptivity,and low IR emissivity makes Ti_(3)C_(2)T_(x) unique existence in nature,which is highly promising for all-day and all-weather energy-saving heating.展开更多
Purpose A C-band photocathode injector composed of a 3.6-cell C-band photocathode RF gun and two 1.8-m C-band accelerating structures is proposed.The injector is a low emittance electron source for free electron laser...Purpose A C-band photocathode injector composed of a 3.6-cell C-band photocathode RF gun and two 1.8-m C-band accelerating structures is proposed.The injector is a low emittance electron source for free electron lasers(FEL)and other compact light sources.Methods The RF structure of the cavities is designed with 2D SUPERFISH simulation.The beam dynamic study in ASTRA helps rectify the 2D RF simulation.To feed the cavities,a design of extracoaxial coupler with RF gun structure is presented.Results With compact focusing solenoids,for 0.25 nC bunch charge,the final energy can reach 6.9 MeV energy and the 95%emittance can be as low as 0.23 mm mrad(95%).Conclusion All the details of RF design and beam dynamics studies are presented in this paper,and the design satisfied the requirements of FEL and other applications.展开更多
基金support of the National Natural Science Foundation of China(Nos.52003248 and 82004001)the China Postdoctoral Science Foundation(Nos.2018M642780 and 2021T140613)+1 种基金the Open-ing Project of State Key Laboratory of Polymer Materials Engineer-ing(Sichuan University)(No.sklpme2019-4-31)the Key Research and Development and Promotion projects of Henan Province(No.202102210032)are gratefully acknowledged.
文摘Realizing all-day and all-weather energy-saving heating is crucial for mitigating the global energy and ecology crisis.Electric/solar heating are two promising heating approaches,yet materials with high elec-trical conductivity,high solar absorptivity,and low infrared emissivity at the same time are rare in na-ture,which are highly anticipated and of great significance for highly efficient electric/solar heating.In this work,we demonstrate that Ti_(3)C_(2)T_(x) MXene with low IR emissivity(14.5%)fills the gap in the absence of the above materials,exhibiting a remarkable electric/solar heating performance.The saturated heating temperature of Ti_(3)C_(2)T_(x) film reaches a record-high value of 201°C at a low driving voltage of 1.5 V,and reaches 84.3°C under practical solar irradiation(750 W/m^(2))with a high solar to the thermal conversion efficiency of 75.3%,which is far superior to other reported materials.Meanwhile,the low IR emissivity endows Ti_(3)C_(2)T_(x) with a remarkable passive radiative heating capability of 7.0°C,ensuring zero-energy heating without electric/solar energy supply.The intrinsic characteristic of high electrical conductivity,high solar absorptivity,and low IR emissivity makes Ti_(3)C_(2)T_(x) unique existence in nature,which is highly promising for all-day and all-weather energy-saving heating.
基金the National Natural Science Foundation of China(No.11675249).
文摘Purpose A C-band photocathode injector composed of a 3.6-cell C-band photocathode RF gun and two 1.8-m C-band accelerating structures is proposed.The injector is a low emittance electron source for free electron lasers(FEL)and other compact light sources.Methods The RF structure of the cavities is designed with 2D SUPERFISH simulation.The beam dynamic study in ASTRA helps rectify the 2D RF simulation.To feed the cavities,a design of extracoaxial coupler with RF gun structure is presented.Results With compact focusing solenoids,for 0.25 nC bunch charge,the final energy can reach 6.9 MeV energy and the 95%emittance can be as low as 0.23 mm mrad(95%).Conclusion All the details of RF design and beam dynamics studies are presented in this paper,and the design satisfied the requirements of FEL and other applications.
