Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered envir...Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC)content,surface chemical structure,light absorption and oxidative potential(OPDTT)of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT)assay.The differences and correlations between soot properties were statistically analyzed.Chemicals/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE)in250 and 365 nm(E2/E3),OPDTT,and higher surface carbonyl content.Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(ArC–O)content,and higher MAE365.The individual comparison of biodiesel/diesel blends showed20%coconut biodiesel blend owned the lowest WSOC,E2/E3 and OPDTT,while highest ArC–O and MAE365,representing strongest absorbing properties.Association analysis showed OPDTTwas significantly positively correlated with WSOC.Further,the evident negative correlation between MAE365 and OPDTT was observed.Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate forcing.Therefore,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel.展开更多
A highly efficient absorbing boundary condition suitable for use in the finitedtherence time-domain (FDTD) modelling of acoustic fields is presented in this paper. The new method seeks a least square esthoate of a tra...A highly efficient absorbing boundary condition suitable for use in the finitedtherence time-domain (FDTD) modelling of acoustic fields is presented in this paper. The new method seeks a least square esthoate of a transfer matrix for field components near truncating boundaries by matrir pseud-inversion. The proposed absorbing boundary is considerably more effective than most ekisting ones. The method is also computationally econondcal and robust.The performance of the new method is shown by numerical experiments on a point-source radiation problem, a wedge dimaction problem, and a scattering problem in which a plane wave is scattered by a circular cylinder.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21577003,21876003)the National Key Research and Development Program of China(No.2016YFC0202200)+1 种基金the Australian Research Council under Discovery Project(No.DP180102632)the special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(No.19Y02ESPCP)
文摘Soot particles,mainly coming from fuel combustion,affect climate forcing through absorbing light and also result in adverse human health outcomes.Though biodiesel or additives blending with diesel was considered environmentally friendly,the understanding on absorbing and oxidative capacity of soot emitted from them are still unclear.The watersoluble organic carbon(WSOC)content,surface chemical structure,light absorption and oxidative potential(OPDTT)of soot from biodiesel/diesel and chemicals/diesel blends were investigated utilizing total organic carbon analyzer,X-ray photoelectron spectrometer,ultraviolet–visible spectrophotometry and dithiothreitol(DTT)assay.The differences and correlations between soot properties were statistically analyzed.Chemicals/diesel blends soot owned significantly higher WSOC content,ratio of mass absorbing efficiency(MAE)in250 and 365 nm(E2/E3),OPDTT,and higher surface carbonyl content.Coconut biodiesel/diesel blends soot contained evidently higher aromatic carbon–oxygen single bond(ArC–O)content,and higher MAE365.The individual comparison of biodiesel/diesel blends showed20%coconut biodiesel blend owned the lowest WSOC,E2/E3 and OPDTT,while highest ArC–O and MAE365,representing strongest absorbing properties.Association analysis showed OPDTTwas significantly positively correlated with WSOC.Further,the evident negative correlation between MAE365 and OPDTT was observed.Our results showed coconut biodiesel/diesel blends soot induced lower levels of oxidative potential,whereas absorption of light was higher,which have far reaching consequences on climate forcing.Therefore,it is important to evaluate the balance point between light-absorbing properties and oxidative potential,under the wide use of biodiesel.
文摘A highly efficient absorbing boundary condition suitable for use in the finitedtherence time-domain (FDTD) modelling of acoustic fields is presented in this paper. The new method seeks a least square esthoate of a transfer matrix for field components near truncating boundaries by matrir pseud-inversion. The proposed absorbing boundary is considerably more effective than most ekisting ones. The method is also computationally econondcal and robust.The performance of the new method is shown by numerical experiments on a point-source radiation problem, a wedge dimaction problem, and a scattering problem in which a plane wave is scattered by a circular cylinder.
