Materials Science Forum Vol. 980

Abstract: Organic-inorganic hybrid perovskite solar cells (PSCs) has attracted growing attention in recent years due to its outstanding photovoltaic performance. After extensive studies in material designs and device engineering, the efficiencies of PSCs have been improved to 24.2%. On the other hand, the inadequate stability of PSCs is hindering the application to real life. Starting with the stability of organic-inorganic PSCs, this article analyzed and concluded the impact of doping A-site and X-site ions on the stability of perovskite respectively. Next, it put forward the prospects for possible development directions of this field in the future.

Abstract: This paper expounds the basic theory of composite mechanics, and discusses the damage forms, damage analysis and failure criteria of composite materials. Then, the basic mechanical properties of unidirectional CFRP laminates with different layers, including modulus of elasticity, strength and so on, were obtained through a large number of experiments. Based on the experimental data, the relationship between the number of layers and the properties of materials was studied. The brittle fracture process of CFRP laminates was simulated by finite element analysis based on progressive damage model and compared with the force-displacement curves obtained by experiments. The validity of progressive damage model was proved.

Abstract: In order to research the ploughing extrusion angle influence on cutting performance and realize the virtual design and manufacture of ploughing-extrusion forming cutter, the plough-extrusion forming process of wick micro-groove structure was simulated by DEFORM-3D software. The micro-copper tube with diameter of 6 mm was simplified to 0.4 mm thick copper plate in this paper. In the simulation process, only the single parameter of tool extrusion angle was changed (45^°, 60^°, and 90^°). The structure, stress and strain distributions of copper plate fins formed by three kinds of extrusion angle cutters were analyzed. It is concluded that the plough-extrusion cutting performance of 60 degree extrusion angle cutter is the best.

Abstract: The 21700 battery is a standard battery used by Tesla vehicles in the United States. It has the advantages of high energy density ratio, high output, low cost and high safety factor. The demand for 21700 battery is gradually increasing on the market. In order to meet the needs of new energy vehicles, the 21700 battery uses copper tab as the anode, which can minimize the internal resistance and improve the charge and discharge efficiency. However, the material of the battery case is steel, and the melting point of the steel is 452°C higher than that of copper. It is difficult to solder firmly using the traditional resistance welding process. In this paper, using TRIZ theory, through the causal analysis, technical conflict, material-field, physical conflicts and other tools, the 21700 battery anode resistance welding problem is analyzed in detail, and based on the analysis results to propose solutions: punching out the pitting on the tab forming a projection welding; inserting metal tungsten in the copper welding head; changing the welding pin head from the platform to the curved surface; introducing nitrogen gas. Under the premise of constant material and no increase in cost, the problem of poor welding of the anode and the battery case can be effectively solved.

Abstract: In this paper, the impact of cutting speed and feed amount on cutting deformation and surface quality and cutter wear have been studied by the test of high manganese steel cutting with metal ceramic tool at high speed. The results show that it is feasible by cutting high manganese steel with cermet tool at high-speed cutting (HSC). Chip changes into succession segment from band in macrostate. Sawteeth can be seen on the top surface of chip while high temperature feature in burning color and cold welding form appear on the bottom of the chip. The model of surface roughness built can be used to predict surface quality at HSC, and provided cutting optimized parameters scheme. Further research indicates that high-speed cutting has its special deformation mechanism and plastic chips exhibit hot brittleness which provides a favorable condition for solving the chip breaking problem in the cutting of high manganese steel.

Abstract: Soybean protein isolate (SPI) is widely used in food industry because of its high protein nutritional function and good functional characteristics. However, due to the effect of amino acid composition and spatial structure on natural protein, its practical application is greatly limited. So it needs to be properly modified to meet the needs of production. In this study, SPI was used as substrate to explore the most suitable modification conditions by using complex enzymes (flavor protease, neutral protease, alkaline enzyme and transglutaminase) enzymolysis and then TG enzyme cross linking, in order to obtain SPI products with both solubility and gel as a special protein isolate for surimi products. The results show that: through the single factor experiment and orthogonal experiment, the optimized conditions of gel strength were determined: flavor protease: neutral protease: alkaline enzyme 1:1:2, pH 7, enzymolysis temperature 45°C, enzymolysis time 30 min. The optimized conditions of solubility: flavor protease: neutral protease: alkaline enzyme 1:2:2, pH 7, enzymolysis temperature 55°C, enzymolysis time 60 min. The result of orthogonal experiment: the optimized conditions was that flavor protease: neutral protease: alkaline enzyme 1:1:2, pH 7, enzymolysis temperature 55°C, enzymolysis time 60 min. The gel strength of products was 35.45 g, decreased 5.33% with control; Solubility was 36.24%, increased 54.01% with control. The modified SPI has excellent gel and solubility, and can be further applied to surimi products industry. And the results of this study provide a theoretical basis for its further application in surimi products.

Abstract: Polyester fabric has the disadvantage of poor hydrophilicity which reduces its wearing comfort and limits its usage in clothing industry. Chitosan especially that of low molecular weight is effective in hydrophilic finishing for polyester fabric, while using plasma processing can greatly improve the effect. This is a green and environmental protection process. Two sets of orthogonal experiments and analysis are done to research the factors that influence the plasma processing effect and the chitosan finishing effect which points out the variation tendency and the best processing conditions.

Abstract: In order to understand the water absorption and purification performance of lotus fiber, the relationship between the structure of lotus fiber and water absorption and purification performance was analyzed through experimental tests. Under standard conditions, the characteristics of the absorption and desorption characteristics of lotus fiber were determined, and from this, the regression equations of moisture regain and time and the equations of the rate of moisture absorption and desorption of lotus fiber during the process of reaching equilibrium between absorption and desorption were deduced.The results showed that the lotus fiber had better absorption and desorption properties, and the resorption and desorption rates of lotus fiber were higher than those of cotton fiber and flax fiber.The moisture absorption rate of lotus fiber is the highest, the flax is centered, and the cotton fiber is the lowest;The water absorption and purification performances of the three fibers were similar, and the lotus fiber was slightly higher than the cotton fiber and the flax fiber.

Abstract: Objective: To study the lipid soluble constituents of wild Russula in Fangcheng-Henan province. Methods: The lipid soluble chemical constituents of wild Russula in henan province were analyzed by GC-MS. Results: The Fatty acids was the highest content of lipid soluble components in wild Russula, 27 compounds were identified, accounting for 99.44% of the total detected components, the main compounds were (E)- 9-octadecenoic acid (44.93%), linoleic acid (28.18%), Palmitic acid (12.07%) and (E)- 12,15-octadecenoic acid (4.17%). Conclusion: The study provides experimental datas for the further development and utilization of wild Russula.

Abstract: The purpose of this study was to evaluate the effects of different polishing techniques on the topographical features and phase transformation of monolithic zirconia. Four brands of zirconia were ground and polished using one of four systems. All zirconia specimens were ground with a fine-grit diamond bur (GB) prior to polishing procedures. The surface roughness and phase transition (XRD) were evaluated, and surface characterizations (SEM and XPS) were performed. The highest roughness was obtained with the Tob system. The strongest diffraction peak in the obtained XRD patterns was at 2θ=30.246°. No monoclinic phase change was found in any group. The XPS analysis showed that the atomic percentages of yttrium in the specimens of Cercon before and after polishing were the highest of any sample. All the polishing systems tested may not adversely affect the phase transformation of monolithic zirconia. The Tob system resulted in the highest roughness. The XPS analysis showed that grinding and polishing had some effects on the properties of zirconia from a microscopic point of view.