针对高中化学与大学无机化学教育教学衔接断裂,大学无机化学课程课时压缩,传统的无机化学教学方式相对保守,教学效果差强人意,已逐渐不能满足快速发展的化学学科的需求,本项目旨在探讨基于培养复合创新型人才的教学目标,构建以OBE-PBL理念为导向的教学模式,对无机化学理论课程教学进行重新设计与评价,促进课程理实一体化教学改革。在整个教学改革实施的过程中,坚持以学生的形成发展为核心,以此引导学生通过知识重塑,建构起学生自身内在的知识体系。通过改革教学过程、考核方式,有效地引导学生学习,激发学生学习兴趣,并增强学生自主学习能力,充分调动学生学习的热情和兴趣,从而有效提高无机化学的教学效果,使学生成为具有化学基础研究和科研实践操作的专业人才,能够实际运用所学知识解决科研中的难题,在未来科研和工作中保持强势的竞争力。In view of the disconnection between high school chemistry and inorganic chemistry education in college and the compression of the teaching hours of inorganic chemistry courses in college, the traditional inorganic chemistry teaching method is relatively conservative, the teaching effect is not satisfactory, and it has gradually failed to meet the needs of the rapidly developing chemistry discipline. This project aims to explore the teaching goal of cultivating composite innovative talents, build an OBE-PBL concept-oriented teaching model, redesign and evaluate the teaching of inorganic chemistry theory courses, and promote the teaching reform of curriculum integration of science and practice. The whole implementation process of teaching reform takes the formation and development of students as the core, in order to guide students to construct their own internal knowledge system through knowledge reconstruction. By reforming the teaching process and assessment methods, we can effectively guide students to learn, stimula
目的:探究金边龙舌兰总皂苷提取率的影响因素,优选总皂苷的提取工艺条件,研究总皂苷的体外抗氧化活性。方法:通过改变乙醇浓度、料液比、超声时间、超声温度等参数,结合正交试验,来优化金边龙舌兰总皂苷的提取过程;利用对DPPH自由基和羟基自由基的清除率进行金边龙舌兰总皂苷的体外抗氧化研究。结果:提取工艺最佳条件为乙醇浓度60%,料液比1:25,超声时间60 min,超声温度80℃,提取率为10.213%。结论:正交试验优选了金边龙舌兰中总皂苷的最优提取过程,体外抗氧化研究验证了金边龙舌兰总皂苷具有一定的抗氧化性能。本研究为金边龙舌兰的进一步开发利用提供了依据。Objective: To explore the factors affecting the extraction rate of total saponins from Agave americana var. Marginata, optimize the extraction conditions of total saponins from Agave americana var. Marginata, and study the antioxidant activity of total saponins from Agave americana var. Marginata in vitro. Methods: By changing parameters such as ethanol concentration, solid-liquid ratio, ultrasound time, ultrasound temperature, and combining orthogonal experiments, the extraction process of total saponins from Agave americana var. Marginata was optimized;In vitro antioxidant study of total saponins from Agave americana var. Marginata using their scavenging rates against DPPH and hydroxyl radicals. Results: The optimum extraction conditions were as follows: the concentration of ethanol was 60%, the ratio of solid to liquid was 1:25, the ultrasonic time was 60 min, and the ultrasonic temperature was 80˚C. The extraction rate was 10.213%. Conclusion: The optimum extraction process of total saponins from Agave americana var. Marginata was optimized by orthogonal test, and the in vitro antioxidant study verified that the total saponins from Agave americana var. Marginata had good in vitro antioxidant activity. This study provides a basis for the further development and utili
文章以硝酸锂和醋酸锰为原料,以水和丙烯酸为分散介质,采用溶胶—凝胶法在空气气氛下进行分段烧结,控制烧结温度和时间,成功制备了尖晶石结构Li Mn2O4粉体材料。通过XRD、SEM、恒电流充放电测试等手段研究了其形态、结构及电化学性能。结果表明:制备出来的粉体为尖晶石型锰酸锂,结晶度高,无杂质相。其中700℃烧结的样品晶粒大小约在58.9 nm,颗粒大小约为200 nm左右。在1 C的电流密度下,首次放电比容量为112 m Ah/g,经过30次循环放电比容量为104.3 m Ah/g,容量保持率在93.2%,充放电库仑效率接近100%。样品表现出良好的电化学性能。
