采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前...采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前后的微观形貌及物相组成。结果表明:HfC的加入降低了炭／炭复合材料的线烧蚀率,其中HfC含量为6．5％(质量分数,下同)的炭／炭复合材料的线烧蚀率最低。HfC具有抑制氧化及弥补缺陷的作用,从而降低了炭／炭复合材料的热化学烧蚀和机械剥蚀。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
Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures fr...Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures from 150 K to 480 K, respectively. Equations for Helmholtz energy, Gibbs energy, internal energy, enthalpy, entropy, isochoric heatcapacity, isobaric heat capacity, speed of sound, and second virial coefficient of HFC-32 arepresented. Independent equations are also included for vapor pressure and saturated liquiddensity as function of temperature.展开更多
文摘采用金属盐溶液浸渍-TCVI(Thermal Gradient Chemical Vapor Infiltration)法制备了HfC改性炭／炭复合材料。通过氧-乙炔烧蚀实验测试了不同含量HfC改性炭／炭复合材料的抗烧蚀性能;利用DSC-TG,SEM,XRD分析了HfC的形成过程、材料烧蚀前后的微观形貌及物相组成。结果表明:HfC的加入降低了炭／炭复合材料的线烧蚀率,其中HfC含量为6．5％(质量分数,下同)的炭／炭复合材料的线烧蚀率最低。HfC具有抑制氧化及弥补缺陷的作用,从而降低了炭／炭复合材料的热化学烧蚀和机械剥蚀。
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Thermodynamic properties of difluoromethane (HFC-32) are expressed in a 35-termcrossover equation of state. This equation of state is effective at pressures up to 35MPa,densities up to 1450 kg.m-3, and temperatures from 150 K to 480 K, respectively. Equations for Helmholtz energy, Gibbs energy, internal energy, enthalpy, entropy, isochoric heatcapacity, isobaric heat capacity, speed of sound, and second virial coefficient of HFC-32 arepresented. Independent equations are also included for vapor pressure and saturated liquiddensity as function of temperature.
