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To investigate the optimal extraction process and antioxidant activity of anthocyanins of Lycium ruthenicum Murr., the anthocyanins of Lycium ruthenicum Murr. were extracted by ultrasonic enzyme-assisted extraction, ethanol/ammonium sulfate aqueous two-phase extraction, ethanol/sodium dihydrogen phosphate aqueous two-phase extraction, and the extraction process was optimized by response surface methodology, the antioxidant model of BRL 3A cells induced by t-BHP was used to explore the protective effect of Lycium ruthenicum Murr. anthocyanins on oxidative stress. The results showed that the yield of ultrasonic enzyme assisted extraction was (17.92 ± 0.04) mg/g; the yield of ethanol/ammonium sulfate aqueous two-phase extraction was (15.46 ± 0.31) mg/g; the extraction yield of ethanol/ sodium dihydrogen phosphate aqueous two-phase system was (15.02 ± 0.19) mg/g. The in vitro antioxidant experiments showed that the antioxidant activity of anthocyanins (LRN) extracted by EtOH/ (NH4)2SO4aqueous two-phase extraction was the strongest, purified EtOH/(NH4)2SO4 aqueous two-phase extraction of anthocyanins (LRNA) can alleviate t-BHP-induced oxidative damage by reducing ROS production in cells. In summary, this process is convenient and stable and can be used for the extraction of anthocyanins from Lycium ruthenicum Murr. At the same time, it also proves that LRN has the strongest antioxidant activity. [ABSTRACT FROM AUTHOR]

A large eddy simulation VOF model is established for the fuel droplet evaporation. The heat and mass transfer characteristics of fuel droplet evaporation in forced convection flow field are investigated. The trend of droplet evaporation is researched by comparing and analyzing the results of heat and mass transfers. The results show that the heat transfer of droplet is not uniformly, but the hot zone is rapidly heated while other zone is slowly heated in the process of droplet evaporation. At the initial time, since the concentration gradient of the fuel droplet at the interface between the vapor and the surrounding gas is high, the initial evaporation rate is rapid and Sh number is larger. Different temperature difference can promote the evaporation process of the droplets. The evaporation rate increases with the increase of the temperature difference. [ABSTRACT FROM AUTHOR]

In order to investigate the reasons for the degradation of dynamic performance of diesel engines under plateau environment, multi-dimensional simulation under different altitudes was conducted to study the combustion process. A set of characteristic parameters accounting for mixing in combustion chamber was established, basing on it, quantitative analysis of the influence of plateau environment on mixing process was conducted. And then the influence of plateau environment on combustion process was investigated mainly by analyzing the heat release rate in the engine. The results show that, under plateau environment, near the wall of combustion chamber easily forms rich mixture, which leads to a reducing of air utilization rate in the center of combustion chamber, a mass of rich mixture still exists at late combustion process. With the rise of altitude, the center area of high temperature moves to the wall of combustion chamber, and causes the deterioration of combustion efficiency. The influence of plateau environment on pre-mixing combustion is not obvious, however, with the rise of altitude, heat release rate of diffusion combustion reduces gradually, and the duration of combustion increases sharply. [ABSTRACT FROM AUTHOR]

In order to explore the mechanism of high-speed diesel engine combustion system parameters on the combustion properties, the matching laws between fuel injection system parameters and combustion chamber structures in high speed direct injection ( HSDI) diesel engine was studied by using three-dimensional CFD numerical simulation method. The spatial distribution of fuel vapour and characteristics of fuel /air mixing were analyzed. In order to quantitatively describe the performance of fuel/air mixing, the parameters about the rate of turbulent mixing and concentration variance of mixture were established. Moreover, weight analysis of the effect of fuel injection system and combustion chamber structural parameters on indicated power was carried out using orthogonal method. The results show that diesel engine power decreases after increasing with the increase of chamber caliber-depth ratio. When the caliber-depth ratio equals to 6. 4, diesel engine is the most powerful, mixing is the most uniform. For different combustion chamber, fuel injection system parameters are of different weights for power. With the combustion chamber caliber-depth ratio increases, the weight of injection pressure decreases, the weight of spray angle of increases, the weight of nozzle number and diameter reduces, the weight of injection timing decreases and then increases. [ABSTRACT FROM AUTHOR]