Long-Term Impact of Wind Erosion on the Particle Size Distribution of Soils in the Eastern Part of the European Union

Wind erosion is the leading cause of soil degradation and air pollution in many regions of the world. As wind erosion is controlled by climatic factors, research on this phenomenon is urgently needed in soil and land management in order to better adapt to climate change. In this paper, the impact of wind erosion on the soil surface in relation to particle size distribution was investigated. Changes in percentage of sand, silt and clay fractions based on historical KPP data (1961–1970), LUCAS data base (2009), and field measurements (2016) were analysed in five cadastral areas impacted by wind erosion (Záhorie Lowlands, Slovakia). With the use of GIS tools, models of spatial distribution of sand, silt, clay and erodible fraction (EF) content were developed based on those measurements. Our findings proved that soil texture change driven by wind erosion could happen relatively quickly, and a significant proportion of soil fine particles may be carried away within a few years. The results indicate that the soil surface became much rougher over the period of more than 50 years, but also that the accumulation of fraction of the silt particles occurred in most of the areas affected by the erosive effect.     

高校化学类专业课程思政建设目标与实现途径刍议——以物理化学课程教学为例

课程思政建设是当前专业课程教学改革的重要内容。课程思政建设应以专业人才培养目标为指引,基于"以学生为中心""以产出为导向"的理念进行系统设计和实施。本文以物理化学课程教学为例,介绍如何围绕课程教学目标,对课程思政进行系统设计,深入挖掘课程育人功能,突出世界观和方法论教学,突出学生综合评价能力、学科思维能力和批判创新能力的培养,推动专业教学由知识导向型向能力和素质导向型转变。     

新工科背景下新能源材料与器件专业有机化学教学改革探索

Under the background of establishing the emerging engineering education, teaching of organic chemistry in engineering specialties needs innovation. Efforts have been made to improve the teaching effect of organic chemistry, including selecting textbooks and teaching contents, reforming teaching methods, improving assessment system, and making the best of organic chemistry laboratory course.     

2000-2018年我国中学化学教育研究的热点与趋势——基于《化学教育》载文的可视化分析

以《化学教育》为研究对象,对近20年的载文进行信息可视化分析,通过绘制关键词共现知识图谱以及关键词时区图,分析并展现2000年以来我国中学化学教育的研究脉络,从整体上把握其研究热点和发展趋势,为后续化学教育的研究和实践提供一些有益的参考。     

化学师范生对化学本质及其教学的认识研究

使用问卷调查法与访谈法,以广东某高校的化学师范生为样本,测查了30名化学师范生对化学本质的认识状况、教学意愿及教学策略。结果表明,（1）师范生对化学本质（包括化学知识的性质、来源、论证、评价等维度）的认识主要体现了辩证唯物主义取向;（2）师范生仅在对个别化学本质维度的认识上涉及到化学的学科专属性;（3）师范生有进行化学本质教学的意愿并能阐述原因,但缺乏进行化学本质教学的策略。据此对我国化学师范生教育及其研究提出相关建议。     

高分子化学双语教学的改革初探与感悟

高分子化学作为一门贴近大众生活的化学类专业课程,是在四大化学(有机化学、无机化学、物理化学、分析化学)基础上,进一步培养高分子专业学生在掌握分子结构设计、合成路线设计、结构性能研究等方面理论知识,能够进一步解决实际问题的能力的课程.高分子化学在基础化学以及高分子物理、聚合物加工与成型等专业课程的设立中起到了很好的桥梁作...     

基于专业认证的高分子材料与工程实验的综合性设计实践

工程专业认证强调以学生为中心,注重培养学生解决复杂工程问题的能力,本文设计了一个综合性的高分子材料与工程实验——高温硫化甲基乙烯基硅橡胶的制备与性能测试.实验要求学生通过文献调研、小组讨论明确实验基本原理的基础上,自主设计实验方案,制备甲基乙烯基硅橡胶制品,测试硅橡胶生胶的分子量、热行为及硫化胶的基本力学性能,以科研论...     

如何做好大学物理演示实验教学

随着素质教育的逐步深入,传统的大学物理演示实验的教学模式已逐步显露出缺点和弊端,结合实际教学,总结出一套大学物理演示实验选修课行之有效的教学方法,为探索新的物理演示实验教学模式提供了新的途径.     

武汉东湖的污染现状与可持续发展对策研究

通过对武汉东湖４０多年来的水生生物、周边环境和水质变化的分析比较，论述了东湖生态系统的人为干扰和变化情况，在对东湖的环境容量研究计算以及最大可持续养鱼量分析的基础上，结合东湖水体的综合功能，提出了武汉东湖可持续发展的对策．     

Optimal and feedback strategies for managing multicohort populations

A Beverton and Holt type linear cohort dynamics model is integrated and combined with a nonlinear stock-recruitment relationship to obtain a discrete-time multicohort harvesting model. Assuming that each age class is individually controllable, it is shown, subject to certain assumptions, that the optimal harvesting strategy is to drive the population to the maximum sustainable yield solution in one time step. In most fisheries, this controllability assumption is not met and harvesting is agewise nonselective. In this case, it may be preferable to implement a harvesting policy based on suboptimal constant effort or stock level feedback strategies, rather than implement a more complicated optimal policy. This question is addressed through numerical studies on the management of an anchovy fishery.Dedicated to G. LeitmannThe author would like to thank M. Mangel, W. Reed, P. Sullivan, and G. Swartzman for commenting on a draft of this paper.