不同版本高中化学教科书中学生必做实验的分析与启示——基于“科学探究与创新意识”素养

以人教版、苏教版、鲁科版(2019年版)和沪科版(2020年版)高中化学教科书中的学生必做实验文本为研究对象,基于“科学探究与创新意识”素养构建高中化学教科书中学生必做实验文本的分析框架,分析和比较4个版本教科书中学生必做实验文本“科学探究与创新意识”素养的体现及其异同,为学生必做实验教学提供启示和建议。     

高中选修模块教材《实验化学》三种版本的比较分析

对人教版、山东科技版、苏教版3种高中化学选修模块教材《实验化学》的结构和内容做了归纳和对比,从教材编写线索、实验分类、学习栏目、插图、习题等几个方面进行比较分析,并提出了几点建议,以利于化学教师对新课标的理解及教材的选用。     

氢氧燃料电池实验的改进

《普通高中化学课程标准（2017年版）》中将“制作简易的燃料电池”列为学生必做实验。针对实验现象不明显的问题，采用铅笔芯做电极，用浸有Na2SO4溶液的海绵代替传统电解液。改进后氢氧燃料电池电流、电压大而且稳定，二极管发光时间长。     

不能用多媒体代替化学实验

多媒体运用于教学的目的是为了促进学生的发展和提高教学的效率.《化学教学大纲》中规定必做的演示实验和学生实验是不能用多媒体来代替的.如果化学实验只让学生看录像或操作鼠标,这样做学生难以获得实验体验,难以形成实验技能.这与国家课程改革要求的加大实验力度,提高学生动手能力,激发学生创新思维是相悖的.     

促进科学观念与科学实践协同发展的学生必做实验的教材编写

国内外科学教育界普遍认为,科学观念与科学实践的协同发展是培养学生科学素养的重要途径。教材对于学生必做实验的编排和处理,对于教师的教学设计及实施具有重要的影响。简要介绍了科学观念与科学实践协同发展的内涵,并针对北京师范大学“新世纪”山东科学技术出版社高中化学必修教材中的学生必做实验编写的整体情况和具体策略进行了深入分析,阐释了该教材对于学生必做实验的编写是如何体现科学观念与科学实践的协同发展、彰显这些实验的核心素养发展功能的,并提出了新教材学生必做实验的教学实施建议。     

高中化学实验选修课内容设置原则的思考

开设校本化学实验选修课是对课堂实验教学的有效补充与拓展,真正发挥校本选修课程的作用就必须为学生提供有效的素材,坚持不做知识下放性实验、不做单纯趣味性实验、不做简单重复性实验,构建成体系的系列内容。尤其在高中化学选修课内容设置上宜在知识运用、实验技术和科学方法等3个方向进行发掘,加大学生的思维容量,提升实验技能和综合素养。     

DIS数字实验探究蜡烛燃烧现象

新课标将科学探究置于各内容主题之首,同时渗透在各主题内容之中,沪教版九年级《化学》教材,为加深学生对灭火原理的认识和提高学生科学素养,演示有关蜡烛的2个实验,然而由于受到实验条件的限制,实验现象的解释学生存在问题,借助数字实验对实验进行设计很好地解决了问题。     

《义务教育化学课程标准(2011年版)》“科学探究”内容重大变化解读

义务教育化学课程标准(2011年版)规定了8个基础的学生实验活动,明确了初中生应学习的7项基本技能.对这些重大变化进行了解读与分析,并就“如何完成好学生实验活动、落实化学实验技能的培养”提出了相应的建议.     

2012年人教版九年级化学教科书中“科学探究”的分析与解读

“科学探究”是一种重要的学习方式,在培养学生的科学素养和创新能力方面发挥着重要作用.对比2011年版与2001年版义务教育化学课程标准中的“科学探究”得知,2011年版课程标准中“科学探究”的描述、基本理念、主题内容、要素与表述有所不同,因此2012年版教科书中科学探究各栏目也发生了相应的变化.本文对2012年版人教版九年级化学教科书中科学探究各栏目的数量、内容及组织形式等变化分别进行了统计分析和解读,并针对这些变化提出了相关的教学建议.     

化学实验教学:冷与热的思考

对比初中化学评优课和常态课中实验教学的状况,分析化学实验在评优课中受热捧而日常教学遭冷遇的原因。依据2011年版义务教育化学课程标准中有关实验教学的规定和要求,提出从化学实验教学功能全面发挥的视角,提高对化学实验及其教学的认识,加强对化学实验教学的研究。建议从强化化学实验的功能意识、加强实验内容和功能的联系、注重实验教学行为的转变、重视学生良好实验习惯的养成等4个方面,提高化学实验教学质量。     

Controlling the elution order of insulin and its analogs in sub-/supercritical fluid chromatography using methanesulfonic acid and 18-crown-6 as mobile phase additives

The purity analysis of therapeutic peptides can often be challenging, demanding the application of more than a single analytical technique. Supercritical fluid chromatography nowadays is a promising alternative to reversed-phase liquid chromatography, providing orthogonal and complementary information. This study investigated its applicability for the separation of human insulin, its analogs and degradation products. A previously published method development protocol for peptides up to 2000 Da was successfully applied to the higher molecular weight insulins (6 kDa). A single gradient method was optimized for all insulins using a Torus DEA column (100 × 3.0 mm, 1.7 μm), carbon dioxide and a modifier consisting of methanol/acetonitrile/water/methanesulfonic acid (65:35:2:0.1, v/v/v/v). Consecutively, the crown ether 18-crown-6, which is well known to complex charged lysine sidechains and other amino functionalities, was added to the modifier to evaluate its impact on selectivity. A decreased retention and a shift in the elution order for the insulins were observed. An inverse effect on retention was found when combined with a neutral stationary phase chemistry (Viridis BEH).     

理科高等院校高分子化学综合实验的创新设计与教学实践

结合近些年我们的教学实践,介绍了为适应综合性理科高等院校不再单独设立高分子本科专业的办学要求,南京大学在综合化学实验课程体系中开设高分子综合性实验的内容设置及教学安排。实验内容主要包括综合性实验和研究性实验两大类,综合性实验要能较为全面地涵盖高分子学科的基本知识点和学生必须掌握的各种实验技能,研究性实验为科研型课题实验。紧密结合研究前沿的创新实验设计起到沟通教学实验与科学研究工作的桥梁作用,缩短了学生进入科研实验室从事课题研究上手的时间,取得了比较好的教学效果。     

ISO 5725 and GUM: comparison and comments

We compare the approach to measure uncertainties proposed in ISO 5725 and GUM from a statistician point of view. In particular we give some warnings to the application of the expanded uncertainty introduced in GUM when the input variables are few and we report some considerations on the relevant role of the interactions among the input variables in the measurement equation as well as the role of statistical design of experiments to measure uncertainties.

高分子基础实验的优化与改革

为适应高分子材料与工程专业实验分层次教学改革的要求,结合我院高分子材料与工程专业的具体实际,在教学内容设计中融入科学、节约、环保的理念,对高分子基础实验体系、内容、组织与运行、教学方法与手段进行了整体优化和改革。使实验成本得到降低,污染物明显减少,实验教学效果得到显著提高,实现了高分子专业基础实验教学效益的最大化。     

A practical thermal analysis course

A practical Thermal Analysis Course is described, lasting one full week, in which the stuents are performing at least 10 experiments from different kinds, covering a broad range of possible applications. In combination with the elaboration of the experiments a number of lectures is given about the practice of thermal analysis. So a course is obtained, in which the students learn a lot of the possibilities (and impossibilities) of thermal analysis techniques, particularly by experiments, performed by their own.Many thanks to Dr. P.L. Ott and Mr. B. Norder for their assistance during the courses, and to Dr. C.M. Hol for his assistance at the printing of this article.     

The accelerated development of an optimized synthesis of 1,2,4-oxadiazoles: application of microwave irradiation and statistical design of experiments

Herein, we report the development of an optimized microwave-assisted synthesis of 1,2,4-oxadiazoles. The chemistry development process was significantly accelerated by employing a statistical software package (MODDE 6.0™) to guide in the optimization of the reaction conditions. The resulting optimized reaction conditions were then utilized in the synthesis of a focused library of 1,2,4-oxadiazoles.     

Partial least squares model and design of experiments toward the analysis of the metabolome of Jatropha gossypifolia leaves: Extraction and chromatographic fingerprint optimization

A major challenge in metabolomic studies is how to extract and analyze an entire metabolome. So far, no single method was able to clearly complete this task in an efficient and reproducible way. In this work we proposed a sequential strategy for the extraction and chromatographic separation of metabolites from leaves Jatropha gossypifolia using a design of experiments and partial least square model. The effect of 14 different solvents on extraction process was evaluated and an optimized separation condition on liquid chromatography was estimated considering mobile phase composition and analysis time. The initial conditions of extraction using methanol and separation in 30 min between 5 and 100% water/methanol (1:1 v/v) with 0.1% of acetic acid, 20 μL sample volume, 3.0 mL min^?1 flow rate and 25°C column temperature led to 107 chromatographic peaks. After the optimization strategy using i‐propanol/chloroform (1:1 v/v) for extraction, linear gradient elution of 60 min between 5 and 100% water/(acetonitrile/methanol 68:32 v/v with 0.1% of acetic acid), 30 μL sample volume, 2.0 mL min^?1 flow rate, and 30°C column temperature, we detected 140 chromatographic peaks, 30.84% more peaks compared to initial method. This is a reliable strategy using a limited number of experiments for metabolomics protocols.     

Isocyanide based multicomponent reactions of oxazolidines and related systems

N-Alkyloxazolidines react in a multicomponent reaction with carboxylic acids and isocyanides to give N-acyloxyethylamino acid amides. The previously reported reaction conditions were improved using a design of experiments approach (DoE). Under the optimised conditions, good yields of the N-acyloxyethylamino acid amide products are obtained both via a three- or four-component approach from N-alkylethanolamines, aldehydes/ketones, isocyanides and carboxylic acids. The reaction of oxazolidines without a nitrogen substituent was found to give either the expected Ugi products or the N-acyloxyethylamino acid amides depending on the choice of reaction conditions. Optimised reaction conditions were also developed for the ring-expansion of oxazolidines to morpholin-2-ones via reaction with an isocyanide followed by hydrolysis. The mechanistic pathway of the multicomponent reaction was briefly investigated using an ¹⁸O labelling experiment. The carboxylic acid component can be replaced by a range of other acidic nucleophiles including thiobenzoic acid, thiophenol or 5-phenyltetrazole, which are incorporated via an alternative pathway. These latter reactions can also be applied to 2-aminotetrahydrofurans, 2-aminotetrahydropyrans or 4-hydroxybut-2-one, further extending the structural diversity of the multicomponent reaction products.     

分析化学验证型实验考核方法的探索与实践*

针对验证型实验的特点,从实验结果、预习成绩、实验操作、实验报告和纪律卫生等5个方面制定了科学合理、客观公正的考核方法。实践证明,该考核方法巩固了基础理论知识,提升了学生实验操作水平,提高了实验教学质量。     

Development and validation of UPLC method for simultaneous quantification of carvedilol and ivabradine in the presence of degradation products using DoE concept

A methodical design-of-experiments were performed by applying quality-by-design concepts to establish a design-space for simultaneous and rapid quantification of Carvedilol and Ivabradine by UPLC in the presence of degradation products. Response-surface, central-composite design, and quadratic model were employed for statistical assessment of experimental data using the Design-Expert software. Response variables such as resolution and retention time were analyzed statistically for chromatographic screening. During DoE study, various plots such as perturbation, contour, 3D and design-space plots were considered for method optimization. The method was developed using C8 [100?×?2.1?mm, 1.8?µ] UPLC column, mobile phase comprising 0.5% triethylamine buffer [pH 6.4] and acetonitrile in the ratio of 50:50 v/v, the flow rate of 0.4?mL minute^?1 and UV detection at 285?nm for both Carvedilol and Ivabradine. The method was developed with a short run time of two minutes. The method was found to be linear in the range of 25.0–199.9?µg?mL^?1 and 8.9–21.3?µg?mL^?1 for Carvedilol and Ivabradine, respectively with a correlation coefficient of 0.9998 in each case. The recovery values were found in the range of 99.7–100.8% and 98.9–100.9% for Carvedilol and Ivabradine, respectively. The method was validated according to ICH Q2 (R1) guidelines.