Black carbon(BC)is considered the second largest anthropogenic climate forcer,but the radiative effects of BC are highly correlated with its combustion sources.On-road vehicles are an important source of anthropogenic...Black carbon(BC)is considered the second largest anthropogenic climate forcer,but the radiative effects of BC are highly correlated with its combustion sources.On-road vehicles are an important source of anthropogenic BC.However,there are major uncertainties in the estimates of the BC emissions from on-road light-duty passenger vehicles(LDPVs),and results obtained with the portable emissions measurement system(PEMS)method are particularly lacking.We developed a PEMS platform and evaluated the on-road BC emissions from ten in-use LDPVs.We demonstrated that the BC emission factors(EFs)of gasoline direction injection(GDI)engine vehicles range from 1.10 to 1.56 mg.km^(-1),which are higher than the EFs of port fuel injection(PFI)engine vehicles(0.10–0.17 mg.km^(-1))by a factor of 11.The BC emissions during the cold-start phase contributed 2%–33%to the total emissions.A strong correlation(R^(2)=0.70)was observed between the relative BC EFs and average vehicle speed,indicating that traffic congestion alleviation could effectively mitigate BC emissions.Moreover,BC and particle number(PN)emissions were linearly correlated(R^(2)=0.90),and compared to PFI engine vehicles,the instantaneous PN-to-BC emission rates of GDI engine vehicles were less sensitive to vehicle specific power-to-velocity(VSPV)increase in all speed ranges.展开更多
Virtually,glass formation is to avoid crystallization during solidification,i.e.,a consequence of the competition between the undercooled liquid and primary crystalline phases.It is found that the crystallization resi...Virtually,glass formation is to avoid crystallization during solidification,i.e.,a consequence of the competition between the undercooled liquid and primary crystalline phases.It is found that the crystallization resistance of the binary Ni-P system was drastically enhanced with alloying of Pd and correspondingly,the critical size for glass formation increased significantly from the micrometer to millimeter scale.Thermodynamically,the introduction of Pd could effectively increase the atomic size mismatch and heat of mixing,which are beneficial to stabilize the supercooled liquid.Kinetically,the introduction of Pd not only successfully suppresses the formation of metastable superlattice phase,which is prone to nucleation and growth in the supercooled liquid state,but also changes the crystallization mechanism from the primary to eutectic mode.The current finding sheds light on understanding glass formation of the most studied Pd-Ni-P system and the glass-forming ability in general.展开更多
基金supported by the National Natural Science Foundation of China(51708327 and 51978404)。
文摘Black carbon(BC)is considered the second largest anthropogenic climate forcer,but the radiative effects of BC are highly correlated with its combustion sources.On-road vehicles are an important source of anthropogenic BC.However,there are major uncertainties in the estimates of the BC emissions from on-road light-duty passenger vehicles(LDPVs),and results obtained with the portable emissions measurement system(PEMS)method are particularly lacking.We developed a PEMS platform and evaluated the on-road BC emissions from ten in-use LDPVs.We demonstrated that the BC emission factors(EFs)of gasoline direction injection(GDI)engine vehicles range from 1.10 to 1.56 mg.km^(-1),which are higher than the EFs of port fuel injection(PFI)engine vehicles(0.10–0.17 mg.km^(-1))by a factor of 11.The BC emissions during the cold-start phase contributed 2%–33%to the total emissions.A strong correlation(R^(2)=0.70)was observed between the relative BC EFs and average vehicle speed,indicating that traffic congestion alleviation could effectively mitigate BC emissions.Moreover,BC and particle number(PN)emissions were linearly correlated(R^(2)=0.90),and compared to PFI engine vehicles,the instantaneous PN-to-BC emission rates of GDI engine vehicles were less sensitive to vehicle specific power-to-velocity(VSPV)increase in all speed ranges.
基金financially supported by the Funds for Creative Research Groups of China(51921001)the 111 Project(BP0719004)+1 种基金the Program for Changjiang Scholars,Innovative Research Team in University of China(IRT_14R05)the National Natural Science Foundation of China(11790293 and 51871016)。
基金supported by the National Natural Science Foundation of China(52071024,52271003,52101188)Guangdong Basic and Applied Basic Research Foundation(2020B1515120077)+4 种基金the Funds for Creative Research Groups of NSFC(51921001)the Projects of International Cooperation and Exchanges of NSFC(51961160729,52061135207)the 111 Project(BP0719004)the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)the Project funded by China Postdoctoral Science Foundation(2020M680009)。
基金This research was supported by the National Natural Science Foundation of China(Nos.51871016,51671021,51671018,51531001 and 11790293)111 Project(B07003)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R05)the Projects of SKL-AMM-USTB(2018Z-01,2018Z-19).H.W.would like to thank the financial support from the Fundamental Research Fund for the Central Universities of China(No.FRF-TP-18-004C1).
文摘Virtually,glass formation is to avoid crystallization during solidification,i.e.,a consequence of the competition between the undercooled liquid and primary crystalline phases.It is found that the crystallization resistance of the binary Ni-P system was drastically enhanced with alloying of Pd and correspondingly,the critical size for glass formation increased significantly from the micrometer to millimeter scale.Thermodynamically,the introduction of Pd could effectively increase the atomic size mismatch and heat of mixing,which are beneficial to stabilize the supercooled liquid.Kinetically,the introduction of Pd not only successfully suppresses the formation of metastable superlattice phase,which is prone to nucleation and growth in the supercooled liquid state,but also changes the crystallization mechanism from the primary to eutectic mode.The current finding sheds light on understanding glass formation of the most studied Pd-Ni-P system and the glass-forming ability in general.
