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Rosa roxburghii residue as raw material, we studied the extraction process of dietary fiber from rosa roxburghii pomace by chemical method. The effects of temperature, time, pH, solid-liquid ratio on the IDF yield under the effect of alkali and acid were explored by single factor experiments and orthogonal experiment. The results showed that the optimal condition of extracting IDF was as follows: the 60 mesh rosa roxburghii pomace were 80 min in water bath at 60°C under the condition of the solid-liquid ratio 1:15 and the pH 12; and then rosa roxburghii pomace were 100 min in water bath at 50°C on the condition of the solid-liquid ratio 1:15, and pH 3.0 after rinsing, the average IDF yield which reached (86.3±1.0)%. This experiment provides experimental basis for the selection of dietary fiber raw materials, and also provides theoretical basis for increasing the added value of rosa roxburghii.

The temporal variations of black carbon concentration at 7 sites, including Longfengshan, Anshan, Benxi, Dalian, Changchun, Shenyang, and Fushun, in Northeast China was studied based on up to 11 years of ground observations and MERRA-2 reanalysis dataset. Except for Benxi, Changchun and Shenyang, at other four sites, the ground-based black carbon concentrations have decreased generally in the last decade, while changes in the black carbon concentration of MERRA-2 are relatively small. The seasonality of measured black carbon concentration shows a trend of low in May-June and high in January at all sites, and the diurnal cycles present similar pattern with two peaks occurring at 10:00-12:00 UTC and 23:00-24:00 UTC respectively, two troughs occurring at 05:00-07:00 UTC and 19:00-20:00 UTC respectively. The daily mean of MERRA-2 black carbon concentration is 49.3% lower than that of the ground observations at 7 sites averagely. They also show poor consistency in terms of seasonal and daily changes, which perhaps means an inappropriate application of MERRA-2 black carbon concentration at single point in Northeast China.

Bimetal composites have wide applications due to their excellent overall performance and relatively low comprehensive cost. The aim of this study is to investigate the forming behaviour of stainless/carbon steel bimetal composite during stamping by finite element method (FEM). In this work, the bonding interface of bimetal composite sheet was assumed to be perfect without delamination during the plastic forming process for simplicity. Uniaxial tensile tests on base metal (carbon steel) and compositing metal (stainless steel) were first carried out, respectively, in order to obtain the tensile properties of each of the component materials required in the forming simulation. Processing variables, including the layer stacking sequence, relative thickness ratios of two layers and friction were considered, and their effects on the distributions of circumferential stress and thickness strain were analysed. The bimetal composite sheet was set as the eight-node solid elements in the developed FEM model, which is effective for evaluating the distributions of circumferential stress and thickness strain, and predicting the high-risk region of necking during the stamping of bimetal composites. The simulation results can be used as an evaluation indicator of the capability of forming machine to ensure the bimetal composite can be safely formed.

Hydrogen is the cleanest high-energy gas fuel, and also is the main industrial material. However, hydrogen is more explosive and more powerful than conventional gas fuels, which restricts its application. In particular, the expansion of premixed combustion under a strong constraint is more complicated, the reaction spreads faster. The flame propagation characteristics of premixed hydrogen/air were investigated by experiment. The mechanism of reaction acceleration is discussed, and then the speed of the flame propagation and the reaction pressure were tested and analysed.