随着我国生态文明建设的不断深入,社会对环境生态教育提出了更高的要求。基于此,文章在OBE(Outcome Based Education,成果导向教育)理念指导下,改进“环境生态学”课程BOPPPS(Bridge-in、Objective、Pre-assessment、Participatory Lear...随着我国生态文明建设的不断深入,社会对环境生态教育提出了更高的要求。基于此,文章在OBE(Outcome Based Education,成果导向教育)理念指导下,改进“环境生态学”课程BOPPPS(Bridge-in、Objective、Pre-assessment、Participatory Learning、Post-assessment、Summary)教学模式,优化培养目标,构建了SPOC(小规模限制性在线课程)课程平台,对课程内容进行模块化重构,开展线上线下混合式教学改革,并将课前学生线上自主学习、课中以学生为主体的多种教学活动、课后知识拓展与训练有机结合,建立了全过程课程考核体系。教学改革有效提高了学生学习的高阶性和创新性,育人成效显著。展开更多
为了提高C/C基体材料在高温有氧环境中的抗烧蚀性能,尝试采用高能等离子喷涂工艺(high power plasmaspraying, HPPS)在C/C基体表面制备SiC涂层。在对SiC涂层制备工艺探索优化过程中共设计了3组HPPS喷涂参数,利用氧乙炔火焰对得到的涂层...为了提高C/C基体材料在高温有氧环境中的抗烧蚀性能,尝试采用高能等离子喷涂工艺(high power plasmaspraying, HPPS)在C/C基体表面制备SiC涂层。在对SiC涂层制备工艺探索优化过程中共设计了3组HPPS喷涂参数,利用氧乙炔火焰对得到的涂层试验进行抗烧蚀性能考核,考核温度为1500℃,时间为150和300 s。通过XRD、SEM和EDS等方法对烧蚀前后涂层样品的成分及组织进行了表征。结果表明:3组参数所制得SiC涂层的孔隙率分别是21.3%、17.4%和15.3%。孔隙率逐渐减小原因是在主气流量相对较高和辅气流量较低的条件下,SiC粉末与等离子射流场特征匹配较好,SiC粉末颗粒加热较为充分,达到更好的熔融状态,而且获得较大的动能,因此所得涂层沉积率逐渐升高而孔隙率逐步降低;在涂层制备过程中SiC颗粒均发生了一定程度的氧化,导致涂层中含有一定量的非晶态SiO_2;经过300 s高温烧蚀考核后,SiC涂层为C/C基体提供了有效的防护。由于烧蚀过程中存在温度梯度,导致涂层表面在烧蚀后呈现3种不同的烧蚀形貌,分别是中心致密区、过渡区和边缘疏松区。在烧蚀过程中,涂层中心区域表面形成的SiO_2玻璃层,有利于阻挡O_2的渗入,起到了抗氧化的作用。展开更多
Dear Editor,Bacteriophages(phages)are viruses that specifically infect and kill bacteria.They are ubiquitous throughout all environments that bacteria inhabit.Following their discovery by F.W.Twort in 1915 and F.d’He...Dear Editor,Bacteriophages(phages)are viruses that specifically infect and kill bacteria.They are ubiquitous throughout all environments that bacteria inhabit.Following their discovery by F.W.Twort in 1915 and F.d’Herele in 1917,bacteriophages were recognized as potential agents to treat bacterial diseases and phage therapy has been used展开更多
文摘随着我国生态文明建设的不断深入,社会对环境生态教育提出了更高的要求。基于此,文章在OBE(Outcome Based Education,成果导向教育)理念指导下,改进“环境生态学”课程BOPPPS(Bridge-in、Objective、Pre-assessment、Participatory Learning、Post-assessment、Summary)教学模式,优化培养目标,构建了SPOC(小规模限制性在线课程)课程平台,对课程内容进行模块化重构,开展线上线下混合式教学改革,并将课前学生线上自主学习、课中以学生为主体的多种教学活动、课后知识拓展与训练有机结合,建立了全过程课程考核体系。教学改革有效提高了学生学习的高阶性和创新性,育人成效显著。
基金supported by the Jilin Industrial Technology Research and Development Projects (Grant number: 2013C015-2)Jilin high tech industry development project
文摘Dear Editor,Bacteriophages(phages)are viruses that specifically infect and kill bacteria.They are ubiquitous throughout all environments that bacteria inhabit.Following their discovery by F.W.Twort in 1915 and F.d’Herele in 1917,bacteriophages were recognized as potential agents to treat bacterial diseases and phage therapy has been used
