＜正＞A novel riboflavin analog, 10-2’-hydroxyethylflavin （HEF）, has strong fluorescence, and it can be used as e...
LI,Hui JIANG, Zhi-Qin PAN, Yang YU, Shu-Qin (Depatment of Chemistry, Tongji University, Shanghai 200092) (Department of Chemical Physics, University of Science and Technology of China, Hefei 230026)
It was reported on the elimination of interfering absorption of BTX. the absorption of O2 includes different absorption bands, which change differently when the partial pressure of oxygen is varied. These cause the nonlinear absorption of O2 and the observed band shape to vary with the column density of O2. The absorption ratios of molecular absorption in each of the Herzberg bands and dimer absorptions, as well as the contribution to the correction error of molecular absorption, are studied based on the characteristic of these absorption bands. The optimized way to eliminate the interfering absorption is obtained in the end and the effectiveness of using interpolation proposed by Volkamer et al. to remove O2 absorption is proved again. As to O2 and SO2, the effect of the thermal effect of characteristic spectra on the elimination error of their absorption is studied. Solutions to these problems are discussed and demonstrated together with methods to optimize the interpolation of spectra. As a sample application, differential optical absorption spectroscopy （DOAS） measurements of BTX are carried out. Results show a low detection limit and the good correlation with point instruments are achieved. All these prove the feasibility of using spectral interpolation to improve the accuracy of DOAS measurements of aromatic hydrocarbons for practical purposes.
Fu-min PengPin-hua XieHai-yang LiYing-hua ZhangJun-de WangWen-qing Liu
Photoinduced electron transfer reactions of N,N,N’, N’- tetramethylbenzidine (TMB) with several electron poor olefins in acetonitrile solution have been studied by using laser flash photolysis and steady-state fluorescence quenching method. The triplet state of TMB at 480nm was found to undergo reductive quenching with the elec- tron acceptors of fumaronitrile, dimethyl fumarate, cinnamonitrile, crotononitrile and diethyl fumarate. The detec- tion of ion radical intermediates in the photolysis reactions confirms the proposed electron transfer mechanism, as expected from thermodynamics. The quenching rate constants of triplet TMB were determined at 510nm, where all the kq values approach or reach to diffusion controlled limit. In addition, fluorescence quenching rate constant T kq was also obtained by calculating with Stern-Volmer equation.
n-Heptane is the most important straight chain paramn in the fossil-fuel industry. In this work, pyrolysis behavior of n-heptane at high temperature is investigated by a se- ties of ReaxFF based reactive molecular dynamics simulations. Temperature effects on the n-heptane pyrolysis and related products distributions have been detailedly analyzed. The simulation results indicate that the temperature effect is characterized in stages. High tern- perature can accelerate the decomposition of n-heptane, but the influence becomes small after it reaches a certain level. According to the different reaction behaviors, pyrolysis of n-heptane could be divided into three stages. The variation trends of the mass fraction evolu- tion of ethylene （C2H4）, C3, and C4 calculated from reactive molecular dynamics simulations are in good agreement with the previous experimental results. The apparent activation en- ergy extracted from the first-order kinetic analysis is 53.96 kcal/mol and a pre-exponential factor is 55.34×10^13 s-1, which is reasonably consistent with the experimental results.
