Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidiz...Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidizing gas flow,the HfC coating forms a high-melting-point heterogeneous oxide layer,significantly delaying oxidation of the underlying material and preserving the structural integrity of the C/C composites[4].展开更多
The multiphoton ionization dissociation of HFC 152a and HFC 134a under the irradiation of 355 nm and 266 nm was studied in this work. Their photolyzed products were analyzed by time of flight mass spectrum instrument....The multiphoton ionization dissociation of HFC 152a and HFC 134a under the irradiation of 355 nm and 266 nm was studied in this work. Their photolyzed products were analyzed by time of flight mass spectrum instrument. The photolyzed products of HFC 152a include H +( m/z =1), C +( m/z =12), CH + 3( m/z =15), C + 2( m/z =24), CF 2H +( m/z =51), and CF +( m/z =31), whereas there is no clear products for HFC 134a photolyzation. Further, the application prospects of HFC 152a and HFC 134a in refrigeration sector were also evaluated from the view point of environmental protection, synthesis conditions and usage performance. It is suggested that HFC 152a is a better alternative compared to HFC 134a in refrigeration sector.展开更多
The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The puriti...The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The purities of HFC152a and HFC32 are all 99.95%.The flow apparatus for measuring heat capacities of liquid phase compounds and their mixtures under the pressure up to 12 MPa,and at temperatures from 26OK to 47OK was built by the authors.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52302115,52231004)。
文摘Hafnium carbide(HfC)serves as a critical ablation-resistant coating for C/C composites used on the wing leading edges of high-speed vehicles during atmospheric re-entry[1-3].Under the action of high-temperature,oxidizing gas flow,the HfC coating forms a high-melting-point heterogeneous oxide layer,significantly delaying oxidation of the underlying material and preserving the structural integrity of the C/C composites[4].
文摘The multiphoton ionization dissociation of HFC 152a and HFC 134a under the irradiation of 355 nm and 266 nm was studied in this work. Their photolyzed products were analyzed by time of flight mass spectrum instrument. The photolyzed products of HFC 152a include H +( m/z =1), C +( m/z =12), CH + 3( m/z =15), C + 2( m/z =24), CF 2H +( m/z =51), and CF +( m/z =31), whereas there is no clear products for HFC 134a photolyzation. Further, the application prospects of HFC 152a and HFC 134a in refrigeration sector were also evaluated from the view point of environmental protection, synthesis conditions and usage performance. It is suggested that HFC 152a is a better alternative compared to HFC 134a in refrigeration sector.
文摘The specific heat capacities of HFC152a/HFC32(92%/8% wt) mixture in liquid phase used in the refrigerator as an alternative for CFC12 are determined and 32 values of heat capacity are reported in this paper.The purities of HFC152a and HFC32 are all 99.95%.The flow apparatus for measuring heat capacities of liquid phase compounds and their mixtures under the pressure up to 12 MPa,and at temperatures from 26OK to 47OK was built by the authors.
