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关键词： 速课堂   物理化学实验   混合式教学  

摘要： 物理化学实验是化学相关专业的必修课,对于物理化学实验的教学我们不能只局限于传统的课堂教学。速课堂是一种线上的教学平台,与传统的教学模式相比,速课堂更加丰富了教学过程在教学中可以创新教学理论、教学手段和教学方法,故而本文的研究对物理化学实验教学方法的混不断创新和高水平人才的培养具有重要参考价值。

关键词： 在线教学   物理化学   钉钉平台   模块教学  

摘要： 介绍了渤海大学的物理化学课程在钉钉平台进行线上授课的主要举措及经验。通过整个学期的实践可知,所构建的“简单–详细–归纳”的模块化教学模式有利于不同自学能力的学生与不同层次的教学相匹配,我问你答式的视频归纳课可以充分调动学生的学习积极性,有利于教学相长和师生互动的完美实现。在细致透明的教学管理、形影相随的过程考核的双重保障下,整个学期的课程总目标达成度达80%以上,分目标达成度均在60%以上,这为相关教学提供了借鉴。

关键词： 雨课堂   “物理化学实验”   混合式教学   教学设计  

摘要： 针对传统线下教学模式在“物理化学实验”课程开展中所存在的难以满足学生的个性化发展、理论课程和实验课程教学进度不一致及单一教材难以满足多元化的教学需求等问题,结合“雨课堂”应用于教学中的优势,该文探讨了一种基于“雨课堂”的线上线下混合式的教学模式在“物理化学实验”课程中的应用模式,并将该模式引入实际的教学过程中,结合具体的教学实例对教学效果进行多维度的分析。研究表明,基于“雨课堂”的混合式教学模式的引入能很好地调动学生的学习热情,提高学生的学习效率,对“物理化学实验”的教学改革具有很好的借鉴作用。

关键词： 安全评价   物理化学方法   应用举措  

摘要： 近年来,我国的各个产业都得到了迅速发展,物理和化学产业方面也取得了长足的进步。其中,物理实验和化学实验的安全性分析和评价作为一项重要的内容,相关的工作人员必须要对此给予足够的重视,并有效地结合一些科学的管理方法,进一步的提升实验的安全性。文章在综合了相关的实际调查和研究后完成,对于物理和化学实验中存在的各种问题进行有效地分析,从而结合安全评价机制的积极作用,推动各种实验的有效开展。

关键词： Brown carbon   Particulate matter   Cytotoxicity   Combustion conditions  

摘要： Light-absorbing organic particulate matter (PM), or brown carbon (BrC), may constitute an important fraction of combustion PM. Here, we investigate the effect of combustion conditions on the molecular sizes of BrC, their light-absorption properties, and their cytotoxicity. We used toluene in a combustion reactor with highly controlled conditions to produce two different types of BrC under two conditions corresponding to smoldering and near-flaming combustion, with temperatures of 670 degrees C and 1035 degrees C, respectively. We performed online measurements of the size distributions and light-absorption properties of the BrC. The BrC produced at 1035 degrees C was more light absorbing, with an imaginary component of the refractive index at 532 nm (k(532)) an order of magnitude larger than that of the BrC produced at 670 degrees C. We also collected samples for offline chemical characterization using laser desorption ionization (LDI) mass spectrometry. The LDI mass spectra showed that the BrC produced at 1035 degrees C was composed of species with significantly larger molecular sizes than the BrC produced at 670 degrees C. Using human lung epithelial cells, we conducted in vitro cytotoxicity analysis on the two types of BrC with doses ranging from 3.5 to 136.0 mu g of BrC/ml. After 24-h exposure, the viability of the cells was assessed using a WST-8 assay. The cytotoxicity analysis showed that, for both BrC samples, the cells exhibited a clear dose-dependent response with significant BrC cytotoxicity that plateaued at the higher doses. However, while the viability of cells exposed to the BrC produced at 1035 degrees C reached a minimum of around 65% at the highest dose, the BrC produced at 670 degrees C proved to be significantly more toxic, with the viability dropping asymptotically to 25%. The results presented here suggest that organic PM of smaller molecular sizes produced under lower temperature, smoldering combustion could be significantly more toxic than tha

关键词： 混合式教学   物理化学实验   云班课  

摘要： 混合式教学模式已成为高校教学改革的趋势之一。针对目前物理化学实验教学现状及存在的问题,探索基于云班课的混合式教学,详细阐述了传统教学与混合式教学的过程,混合式教学模式在物理化学实验教学中的应用,使得学生学习的积极性提高,创新能力和实践能力增强,课堂效率和教学效果大大提高。

关键词： Soilless revegetation   Gold mine tailings   Physicochemical properties   Microbial metabolic activity   Microbial community structure  

摘要： Soilless revegetation is a cost-effective and eco-friendly method for the ecological restoration of gold mine tailings. However, due to gold mine tailings are high-salty, alkaline and low-nutrient, little research has been done on soilless revegetation of gold mine tailings. The aim of study was to apply soilless revegetation to gold mine tailings, and investigate the changes of physicochemical properties and microbial communities of tailings after soilless revegetation. Six selected herbaceous plants (Melilotus officinalis, Xanthium sibiricum, Festuca elata, Zoysia japonica, Amaranthus tricolor L., Artemisia desertorum) grew well on the bare tailings, and their heights reached as high as 16.28 cm after 90 days. After soilless revegetation, tailings salinity dramatically dropped from 547.15 to 129.24 mu S cm(-1), and pH went down from 8.68 to 7.59 at most. The content of available phosphorus (AP), available nitrogen (AN) and organic matter (OM) in tailings gradually improved, especially the content of AP and OM increased 53.36% and 52.58%, respectively. Furthermore, microbial metabolic activity and diversity in tailings obviously increased 70.33-264.70% and 1.64-13.97% respectively. The relative abundance of potential plant growth-promoting bacteria increased 1.40-3.05%, while the relative abundance of opportunistic pathogens and halophilic bacteria decreased 10.58-17.03% and 2.98-6.52% respectively. Such variations of microbial communities were beneficial for tailings restoration. This study provided insight into soilless revegetation and its impact on tailings microorganisms, which could be a new strategy for ecological restoration of gold mine tailings.

关键词： 物理化学   实践创新   应用型人才   教育教学  

摘要： 应用型人才的培养对于高等院校的教育教学模式提出了挑战,为全面提升学生的创新能力和实践操作水平,从基础理论课程出发,引导学生参与到实践创新中来,可以更好的提升学生的综合素质。以物理化学课程为例,分析了物理化学课程实践教学改革与应用型人才培养之间关系,从而促进物理化学课程教学质量的提高。

关键词： 在线课程   课程设计   物理化学   热力学第二定律   卡诺热机  

摘要： 提出在线课程应立足于对线下课堂教学内容的疏导、梳理、凝练和升华,并以"热力学第二定律与卡诺热机"在线课程为例进行介绍。采用问题链形式引导学生从卡诺热机推导热力学第二定律数学表达式,阐明了卡诺热机在热力学第二定律形成过程中的重要作用和地位,强调了卡诺对于热力学的重要贡献,培养了学生探究精神和学科素养。为在线课程提供了教学案例和设计思路。

关键词： Sprouting   Amylopectin   Drought stress   Crystallinity   HPAEC-PAD  

摘要： In this study, starches from underground stems of Trimezia Pont-Vona were evaluated during dry season (DSS), wet season (WSS) and sprouting (SS). Results evidenced that drought stress did not interfere with the yield, amylose content and degree of polymerization (DP) of amylopectin. However, the extraction yield in SS was 58% lower, being observed and increase of 7.5% in the content of amylose, and 135% in DP values for SS amylopectin, with a predominance of A-chains. The amount of total sugar, the starch granules size as well as solubility and swelling properties varied as function of the phenological status. Also, starch granules changed from A-type polymorph in DSS and SS to a C-A-type in WSS. Nevertheless, it was observed a crystallinity reduction from 56% in DSS to 37.1% in SS. In addition, thermograms evidenced the presence of amylose-lipid complexes, with endothermic transition temperatures being affected by drought stress and sprouting. Finally, results demonstrate that underground stems from T. juncifolia have adaptative strategies involving changes in the morphological and physicochemical properties of the starch granules. (C) 2020 Elsevier B.V. All rights reserved.