基于学科理解的“物质成分”大概念教学*

以“物质成分”大概念教学为例,基于学科理解,以探究物质成分的相关化学史为线索设计教学,引导学生在追溯“物质成分”相关概念、理论的发展过程中,逐渐建构物质成分的宏观、微观、宏微结合视角。并在解决探究物质成分的真实问题的过程中,培养学生基于证据进行推理的科学论证能力,通过认识视角的发展,体会科学理论是在不断发展和进阶的,初步建立科学发展观。     

聚焦学科核心素养提升的初中化学教学探索—以“酸的化学性质”为例

以酸的化学性质为载体,对知识进行上位和深层整合,将核心知识、学习活动与评价紧密结合,借助完整的科学探究,应用“宏观、微观、符号表征相结合”的学科思维方式,增进“组成构成决定性质、性质决定用途”学科思想的理解,培养高级思维和创新能力。自主建构“元素组成和微粒种类统领角度下的基于类别认识物质化学性质”的整体思维模型,实现物质化学性质认识的角度进阶。聚焦涵盖学科知识,积淀学科核心素养,落实学科育人的初中化学教学,实现初高中衔接。     

整合多重表征 促进概念深度理解——以“原电池”为例

有效整合多重表征,是促进学生科学概念深度理解的一种有效策略。本研究整合了科学教育领域中的3个多重表征框架的内容,对高中必修模块的“原电池”进行了教学设计。首先引导学生依次学习原电池的宏观装置、微观原理和电极符号,初步建构原电池概念,之后基于氢氧燃料电池关联表征,让学生建构原电池的装置原理二维模型图,理解原电池概念,最后依托生活中的纽扣电池应用二维模型图实现表征转换,解决实际问题,实现对原电池概念的深度理解。     

模型本质观进阶框架的理论构建及实证研究

在科学学习中,模型本质观是科学素养的关键组成。本研究基于对已有“模型本质观”研究的分析,建构了“模型本质观”的进阶框架,并对初、高中及大学共计381名学生进行调查。研究表明：学生普遍存在对模型本质认识的迷思概念,在“模型和实物间的关系”维度尤为突出。     

“素养为本”的化学课堂教学*——以“原子晶体”为例

基于“素养为本”视角,以“原子晶体”的教学为例,对教学主题内容、教学现状及学情进行分析;以发展学生化学学科核心素养为主旨确定教学目标;以“微粒-微粒间的相互作用-物质的聚集状态-物质性质”的认识思路为主线,以“模型认知,建构概念-证据推理,归纳性质-微观探析,探究结构-科学史实,揭示价值”的任务型教学流程,达到落实并发展学生化学学科核心素养的目的。     

基于SOLO分类理论的单元教、学、评一体化学习进阶设计——以“金属及其化合物”为例

针对目前化学课堂中存在的教学内容零散化、评价过程没有落实学生高阶思维能力发展的问题,以SOLO分类理论为依据,基于已有研究对教学内容进行概念优化整合,建构了 “金属及其化合物”单元学习进阶模型,进而以“钠及其化合物”为例设计了教学活动,然后根据教、学、评一体化的理念,设计了相应的教、学、评一体化评价框架。     

基于思维模型建构的“物质检验”初中复习教学研究

以让学生自主建构物质检验的思维模型为目标设计教学,通过完成物质检验的探究任务,学生自主建构思维模型,形成完整的思路,从而提高解决此类问题的能力。并在北京某中学初三年级进行教学实践,对教学实施效果进行了检验,根据教学实践总结出建构“物质检验”思维模型教学的有效教学策略：基于建模历程与生活情境选择素材;以学生为中心自主建构“物质检验”思维模型,引导学生经历多样化的思维发展过程;学生经历不同层级进阶的模型建构历程。     

日本初中理科教科书中“粒子的存在”内容选择及启示

日本理科课程中“粒子”科学概念主要与化学课程相关,“粒子的存在”是“粒子”的首要核心概念,主要发展学生从微观层面认识物质的性质、结构及2者之间关系的能力,明确物质是由粒子构成的,粒子包括分子、原子和离子等,且粒子的性质决定物质的性质。从“重要事实”“核心内容”和“主要观念”3个方面自下而上对日本《新科学》教科书中“粒子的存在”相关内容的选择进行分析,发现《新科学》教科书在内容选择上具有注重“粒子模型”构建的层次性和观念层面要求显性化的特征。     

“铜元素化合物”的高三线上主题式复习*

以高三复习课“铜元素化合物”的教学为例,基于主题教学思想,从“价类二维图”出发,引导学生从物质类别、氧化还原和化学平衡等多角度认识元素化合物间的相互转化,实现了主题内容的关联与进阶,促进了学生思维能力的提升和学科观念的建构。本节课是网络直播课,采用“腾讯课堂”平台,学生可以连麦回答问题,学生设计的实验方案发布在班级微信上,由教师共享屏幕,则所有学生可见。     

回归知识本原 构建生命课堂——以“常见物质的检验”为例

以“常见物质的检验”的教学为例,运用化学史料帮助学生自主建构知识体系,促进学生追寻知识本原,实现思维进阶,发展核心素养,并阐述运用化学史料构建高中化学生命课堂的实施策略。     

Diterpenoids from the Buds of <em>Pinus banksiana</em> Lamb

Three new diterpenoids, namely 7α-hydroxyabieta-8,11,13,15-tetraen-18-oic acid, 7β,15,18-trihydroxyabieta-8,11,13-triene, 13,15-dihydroxypodocarpa-8,11,13-triene, and 12 other known compounds were isolated from buds of Pinus banksiana Lamb. All these compounds, except for 7-oxodehydroabietinol, were isolated for the first time from this plant. Their structures were elucidated by detailed spectroscopic studies and comparison with published data. All isolated compounds were tested for cytotoxic and antibacterial activities. Overall, two compounds, 7-oxodehydroabietinol and 18-nor-4,15-dihydroxyabieta-8,11,13-trien-7-one, showed moderate cytotoxicity against a human lung carcinoma cell line.     

“宏观辨识与微观探析”视域下的初中化学教学*——中和反应

在“宏观辨识与微观探析”视域下进行中和反应教学,首先以常规实验为载体,从宏观视角认识中和反应的外在表现,然后以模型、动画为载体,从微观视角了解中和反应的微观过程,再以数字化实验为载体,从宏观与微观相结合的视角理解中和反应的内在本质,最后联系生产生活实际,体验中和反应的应用价值。这样设计,学生能深刻理解中和反应的本质,增进化学学科理解,培养化学学科核心素养。     

Nanofold‐decorated surfaces from the electrodeposition of di‐alkyl‐cyclopentadithiophenes

This work describes the synthesis and subsequent electrodeposition of 4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene (cyclopentadithiophene) monomers di‐substituted with alkyl chains. Each monomer was electropolymerized in solution to observe their capacity at creating well‐structured, rough surfaces. The length of the alkyl chain substituent has a significant influence on the overall surface morphology and wetting behavior after electropolymerization. In the case of nonsubstituted cyclopentadithiophene monomers or those with short alkyl (methyl and ethyl) substituents, the polymerization proceeds readily, forming rough surfaces that follow the Wenzel regime of wetting. In these cases, the surfaces were decorated with globular agglomerates and woven mat features. The measured surface roughness decreases with alkyl chain length as steric hindrance caused by the alkyl substituents limits electropolymerization. As the alkyl chain substituent increases to propyl chain length and beyond, the increase in steric hindrance is so significant that the surface morphology formed during electrodeposition is primarily due to π‐stacking interactions between very short oligomers formed in solution. With propyl and butyl substituents, nanofold morphology is observed, leading to surfaces with much higher contact angles with water (~132°) that follow the Cassie‐Baxter regime of wetting. This type of surface morphology has only been demonstrated one other time and with the use of fluorinated constituents. This work exposes a mild, fluorine‐free synthetic route to creating nanofold‐decorated surfaces.     

Phenolic Antioxidants Isolated from the Flowers of <em>Osmanthus fragrans</em>

O. fragrans has slightly less antioxidative activity than green tea. Five phenolic compounds, tyrosyl acetate (1), (+)-phillygenin (2), (8E)-ligustroside (3), rutin (4), and verbascoside (5), were isolated from the CHCl₃ sub-extract of O. fragrans. The structures were elucidated by interpreting their spectral data. Evaluation of the antioxidative property of the isolated (+)-phillygenin (2), rutin (4), and verbascoside (5) revealed strong DPPH radical scavenging activity, with IC₅₀ values of 19.1, 10.3, and 6.2 μM, respectively. These isolates also exhibited an H₂O₂ scavenging ability, with IC₅₀ values of 10.5, 23.4, and 13.4 μM, respectively.     

Alkaloids Isolated from the Lateral Root of <em>Aconitum carmichaelii</em>

Two new alkaloids, aconicarmine (1) and aconicaramide (5), were isolated from the EtOH extract of the lateral roots of Aconitum carmichaelii, together with five known compounds: fuziline (2), neoline (3), N-ethylhokbusine B (4), 5-hydroxymethylpyrrole-2-carbaldehyde (6), and oleracein E (7). Their structures were elucidated by physical and NMR analysis. Pyrrole alkaloids were isolated from A. carmichaelii for the first time. In the in vitro assays, compounds 2 and 3 showed activity against pentobarbital sodium-induced cardiomyocytes damage by obviously recovering beating rhythm and increasing the cell viability, while compounds 5 and 7 showed moderate antibacterial activity.     

Oxygen desorption from polycrystalline palladium: Thermal desorption of O<Subscript>2</Subscript> from a chemisorbed layer of O<Subscript>ads</Subscript> in the course of the decomposition of PdO surface oxide and in the release of oxygen from the bulk of palladium

The desorption of oxygen from polycrystalline palladium (Pd(poly)) was studied using temperature-programmed desorption (TPD) at 500–1300 K and the amounts of oxygen absorbed by palladium (n) from 0.05 to 50 monolayers. It was found that the desorption of O₂ from Pd(poly), which occurred from a chemisorbed oxygen layer (O_ads), in the release of oxygen from a near-surface metal layer in the course of the decomposition of PdO surface oxide, and in the release of oxygen from the bulk of palladium (O_abs), was governed by repulsive interactions between O_ads atoms and the formation and decomposition of O_ads-Pd*-O_abs structures (Pd* is a surface palladium atom). At θ ≤ 0.5, the repulsive interactions between O_ads atoms (ɛ_aa = 10 kJ/mol) resulted in the desorption of O₂ from Pd(poly) at 650–950 K. At 0.5 ≤ n ≤ 1.0, the release of inserted oxygen from a near-surface palladium layer occurred during TPD in the course of the migration of O_abs atoms to the surface and the formation-decomposition of O_ads-Pd*-O_abs structures. As a result, the desorption of O₂ occurred in accordance with a first-order reaction with a thermal desorption (TD) peak at T _max ∼ 700 K. At 1.0 ≤ n ≤ 2.0, the decomposition of PdO surface oxide occurred at a constant surface cover-age with oxygen during TPD in the course of the formation-decomposition of O_ads-Pd*-O_abs structures. Because of this, the desorption of O₂ occurred in accordance with a zero-order reaction at low temperatures with a TD peak at T _max ∼ 675 K. At 1.0 ≤ n ≤ 50, oxygen atoms diffused from deep palladium layers in the course of TPD and arrived at the surface at high temperatures. As a result, O₂ was desorbed with a high-temperature TD peak at T > 750 K.     

Composition of the lipophilic extract from the sponge <Emphasis Type="Italic">Axinella carteri</Emphasis> collected from the Bay of Bengal of the Orissa coast

The composition of the lipophilic extract from the two specimen of the sponge Axinella carteri (Dendy) collected from two different depths of the Bay of Bengal of the Orissa coast were investigated. Fatty acids, as well as volatile compounds and sterols, were identified. A high concentration of polyunsaturated fatty acids was identified from depth species compared to the species collected from shallow water. The presence of a high concentration of a polymethyl-branched fatty acid, i.e., phytanic acid, and a demospongic acid (C26:2, Δ 5,9) were identified in both specimen, but the % composition of both acids were more in the species collected from depth than the species collected from shallow water. Important polyunsaturated fatty acids like 5,8,11,14-eicosatetraenoic acid and 5,8,11,14,17-eicosapentaenoic acid (EPA) were also found in depth species which were absent in the species collected from shallow water. Antimicrobial screening of the lipid extracts of A. carteri was also studied against different pathogens. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 224–227, May–June, 2008.     

Disesquiterpenoid and Sesquiterpenes from the Flos of <i>Chrysanthemum indicum</i>

One new disesquiterpenoid (1), two new sesquiterpenoids (2, 3), were isolated from the dry flos of Chrysanthemum indicum. The structures were elucidated by spectroscopic analysis, the absolute configurations of 1 and 3, were determined by single X-ray diffraction study.