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21.
我国是煤炭资源大国,煤层气储量规模相当可观,但煤储层又具有低孔、低渗的不足,照搬国外或常规石油天然气的开采程序和方法已被证实是走不通的。应结合实际,根据不同地质条件、不同煤阶的开采程序,进行孔隙特征研究。煤孔隙特征、连通性和吸附能力对煤层气开采影响尤为重要,为研究煤孔隙结构特征随煤变质程度的变化关系及其吸附能力的响应特点,采取不同地区不同变质程度煤样,进行压汞测试和等温吸附实验。实验结果表明,煤孔隙度和平均孔径均随变质程度增加呈现降低—升高—降低的趋势;煤中孔隙连通性随煤变质程度增加逐渐变差;随煤变质程度增加,其最大吸附能力也呈现降低—升高—降低的总体趋势。 相似文献
22.
AbstractThe impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR. 相似文献
23.
24.
The time window for effective climate change mitigation is closing. Technological change needs to be accelerated to limit global warming to a manageable level. Path dependence of technological change is one explanation for sluggish diffusion of green technologies. Firms acquire capital that differs by technology type and build up type-specific technological know-how needed to use capital efficiently. Path dependence emerges from cumulative knowledge stocks manifested in the productivity of supplied capital and firms’ capabilities. Increasing returns arise from induced innovation feedbacks and learning by doing. Relatively lower endowments with technological knowledge are a barrier to diffusion for new technologies. This paper shows how the evolution of relative stocks of technological knowledge explains different shapes of diffusion curves. Using an eco-technology extension of the macroeconomic agent-based model Eurace@unibi, it is shown how the effectiveness of different climate policies depends on the type and strength of diffusion barriers. Environmental taxes can outweigh lower productivity and subsidies perform better if lacking capabilities hinder firms to adopt a sufficiently mature technology. 相似文献
25.
Jeong Ha-Ram Cho Hye-Seung Cho Youn-Sup Kim Dae-Ok 《Food science and biotechnology》2020,29(12):1763-1770
Food Science and Biotechnology - Hardy kiwifruits (Actinidia arguta) contain various bioactive compounds such as vitamin C and phenolics and can withstand cold temperatures. Changes in soluble... 相似文献
26.
不同粒径改性粉煤灰对磷酸根吸附性能的影响 总被引:1,自引:0,他引:1
废水排放过量的磷导致水体污染日益严重,将粉煤灰通过化学改性制备成了水化硅酸钙吸附剂,研究了改性吸附剂对磷酸根的吸附效果。利用XRD, SEM及BET比表面积等手段对粒度分级前后的吸附剂进行表征,研究不同粒级吸附剂对磷酸根的吸附性能,并考察其吸附机理。结果表明,不同粒级的吸附剂其化学成分出现了明显的偏析现象,孔隙结构也差异显著。相比其他粒径下的吸附剂颗粒,颗粒粒径在50?75 μm时,吸附剂中钙和硅含量较多,铝、铁和镁含量较低,水化硅酸钙组分含量最高,且伴有含铝的托贝莫来石晶体出现,钙离子的增加使其可以与更多的磷酸根结合形成沉淀。同时此粒径下具有较高的比表面积及孔隙度,疏松多孔的结构为钙离子提供更多活性位点。当使用粒径在50?75 μm的吸附剂吸附磷酸根时,磷的饱和吸附量可达到17.1 mg/g,比未分级的吸附剂高19.58%。 相似文献
27.
分析了乙炔发生器发气能力低的原因,对发生器温度、发生器压力及发生器耙齿等方面进行了改进,提高了发气量。 相似文献
28.
Gd and Al co-doped LiMn2-x(GdAl)xO4 (x?=?0, 0.01, 0.02, 0.03, 0.04 and 0.05) materials with spinel structure were synthesized by sol–gel method. Powder X-ray diffraction results confirm the formation of cubic spinel structure and average particle sizes are found to be between 80 and 110?nm from FE-SEM and TEM analysis. Decrease in peak potential difference as a function of doping in Cyclic Voltammetry results establishes enhancement in Li+ intercalation and de-intercalation. Electrochemical Impedance Spectroscopy (EIS) results showed that accumulation of charges on electrode has improved with doping over pristine samples. At a doping of x?=?0.02 charge transfer resistance values were found to be least. First cycle charge–discharge profiles for LiMn1.96(GdAl)0.02O4 shows 139.2?mAh/g discharge capacity over other doped derivatives and pure LiMn2O4 (119.6?mAh/g) in aqueous Li2SO4 electrolyte. Doping of x?=?0.02 exhibit good cycling performance with only a total 4% capacity loss after 30 cycles. 相似文献
29.
Rock joints infilled with sediments can strongly influence the strength of rock mass. As infilled joints often exist under unsaturated condition, this study investigated the influence of matric suction of infill on the overall joint shear strength. A novel technique that allows direct measurement of matric suction of infill using high capacity tensiometers (HCTs) during direct shear of infilled joints under constant normal stiffness (CNS) is described. The CNS apparatus was modified to accommodate the HCT and the procedure is explained in detail. Joint specimens were simulated by gypsum plaster using three-dimensional (3D) printed surface moulds, and filled with kaolin and sand mixture prepared at different water contents. Shear behaviours of both planar infilled joints and rough joints having joint roughness coefficients (JRCs) of 8–10 and 18–20 with the ratios of infill thickness to asperity height (t/a) equal to 0.5 were investigated. Matric suction shows predominantly unimodal behaviour during shearing of both planar and rough joints, which is closely associated with the variation of unloading rate and volumetric changes of the infill material. As expected, two-peak behaviour was observed for the rough joints and both peaks increased with the increase of infill matric suction. The results suggest that the contribution of matric suction of infill on the joint peak normalised shear stress is relatively independent of the joint roughness. 相似文献
30.
《Geotextiles and Geomembranes》2020,48(5):647-654
In this study, an experimental investigation has been conducted on a circular footing model subjected to eccentric load resting on the geonet-reinforced sand. To this end, five series of tests were carried out in order to evaluate the effect of reinforcement dimension and eccentricity on the bearing capacity, settlement, and rotation of the footing. Results show that the bearing capacity ratio (BCR) is in direct relationship with eccentricity and the impact of soil reinforcement at low settlements is much more significant in the case of eccentric loading. Additionally, the bearing capacity interaction diagram and variation in the position of rotation line at different load levels for reinforced and unreinforced conditions are presented. 相似文献