The SCC susceptibility of type 321 stainless steel in acidic chloride solution has been studied by slow strain rate testing (SSRT) and SEM. During the slow rate tensile process, the specimen was polarized with differe...The SCC susceptibility of type 321 stainless steel in acidic chloride solution has been studied by slow strain rate testing (SSRT) and SEM. During the slow rate tensile process, the specimen was polarized with different potential perturbation modes such as cyclic potential scan and cyclic potential step methods. The results indicated that the potential scan rate or step frequency played an essential role in the initiation and propagation of crack.展开更多
In this paper Lp Lq estimates for the solution u(x,t) to the following perturbed higher order hyperbolic equation are considered,(οtt-aΔ)(οtt-bΔ)u+V(x)u=0,\ x∈Rn,n≥6, οjtu(x,0)=0,\ ο3tu(x,0)=f(x),\ (j=0,1,2).W...In this paper Lp Lq estimates for the solution u(x,t) to the following perturbed higher order hyperbolic equation are considered,(οtt-aΔ)(οtt-bΔ)u+V(x)u=0,\ x∈Rn,n≥6, οjtu(x,0)=0,\ ο3tu(x,0)=f(x),\ (j=0,1,2).We assume that the potential V(x) and the initial data f(x) are compactly supported, and V(x) is sufficiently small, then the solution u(x,t) of the above problem satisfies the same Lp Lq estimates as that of the unperturbed problem. Received November 25,1996. Revised April 14,1997.1991 MR Subject Classification:35L05,35B20,35B45.展开更多
In order to evaluate the secondary aerosol formation potential at a suburban site of Beijing,in situ perturbation experiments in a potential aerosol mass（PAM） reactor were carried out in the winter of 2014.The varia...In order to evaluate the secondary aerosol formation potential at a suburban site of Beijing,in situ perturbation experiments in a potential aerosol mass（PAM） reactor were carried out in the winter of 2014.The variations of secondary aerosol formation as a function of time,OH exposure,and the concentrations of gas phase pollutants and particles were reported in this study.Two periods with distinct secondary aerosol formation potentials,marked as Period Ⅰ and Period Ⅱ,were identified during the observation.In Period Ⅰ,the secondary aerosol formation potential was high,and correlated well to the air pollutants,i.e.,SO2,NO2,and CO.The maximal secondary aerosol formation was observed with an aging time equivalent to about 3 days of atmospheric oxidation.In period Ⅱ,the secondary aerosol formation potential was low,with no obvious correlation with the air pollutants.Meanwhile,the aerosol mass decreased,instead of showing a peak,with increasing aging time.Backward trajectory analysis during the two periods confirmed that the air mass in Period Ⅰwas mainly from local sources,while it was attributed mostly to long distance transport in Period Ⅱ.The air lost its reactivity during the long transport and the particles became highly aged,resulting in a low secondary aerosol formation potential.Our experimental results indicated that the in situ measurement of the secondary aerosol formation potential could provide important information for evaluating the contributions of local emission and long distance transport to the aerosol pollution.展开更多
文摘The SCC susceptibility of type 321 stainless steel in acidic chloride solution has been studied by slow strain rate testing (SSRT) and SEM. During the slow rate tensile process, the specimen was polarized with different potential perturbation modes such as cyclic potential scan and cyclic potential step methods. The results indicated that the potential scan rate or step frequency played an essential role in the initiation and propagation of crack.
文摘In this paper Lp Lq estimates for the solution u(x,t) to the following perturbed higher order hyperbolic equation are considered,(οtt-aΔ)(οtt-bΔ)u+V(x)u=0,\ x∈Rn,n≥6, οjtu(x,0)=0,\ ο3tu(x,0)=f(x),\ (j=0,1,2).We assume that the potential V(x) and the initial data f(x) are compactly supported, and V(x) is sufficiently small, then the solution u(x,t) of the above problem satisfies the same Lp Lq estimates as that of the unperturbed problem. Received November 25,1996. Revised April 14,1997.1991 MR Subject Classification:35L05,35B20,35B45.
基金supported by the Key Research Program of Chinese Academy of Sciences (No. KJZD-EW-TZ-G06-01-15)the National Natural Science Foundation of China (No. 21407158)the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (No. XDB05010300)
文摘In order to evaluate the secondary aerosol formation potential at a suburban site of Beijing,in situ perturbation experiments in a potential aerosol mass（PAM） reactor were carried out in the winter of 2014.The variations of secondary aerosol formation as a function of time,OH exposure,and the concentrations of gas phase pollutants and particles were reported in this study.Two periods with distinct secondary aerosol formation potentials,marked as Period Ⅰ and Period Ⅱ,were identified during the observation.In Period Ⅰ,the secondary aerosol formation potential was high,and correlated well to the air pollutants,i.e.,SO2,NO2,and CO.The maximal secondary aerosol formation was observed with an aging time equivalent to about 3 days of atmospheric oxidation.In period Ⅱ,the secondary aerosol formation potential was low,with no obvious correlation with the air pollutants.Meanwhile,the aerosol mass decreased,instead of showing a peak,with increasing aging time.Backward trajectory analysis during the two periods confirmed that the air mass in Period Ⅰwas mainly from local sources,while it was attributed mostly to long distance transport in Period Ⅱ.The air lost its reactivity during the long transport and the particles became highly aged,resulting in a low secondary aerosol formation potential.Our experimental results indicated that the in situ measurement of the secondary aerosol formation potential could provide important information for evaluating the contributions of local emission and long distance transport to the aerosol pollution.
