《化学教育》中化学史文献的统计分析——基于2007—2016年载文的研究

以2007—2016年《化学教育》杂志中“化学史与化学史教育”栏目中文章作为研究分析对象,从载文情况、作者情况、引文情况等3个方面进行统计,分析近十年来化学史教育教学研究的趋势和薄弱环节,并提出几个参考性的建议。     

人教版高中化学必修模块教科书实验活动的分析与比较*——以2019年版教科书“实验”和“实验活动”栏目为例

以人教版高中化学必修模块教科书(2019年版)“实验”和“实验活动”栏目的实验活动为研究对象,采用Herron修正的“实验活动探究层次分类法”(LOLA)和笔者提出的“学生实验行为要求分类法”(RSBLA)对其进行分析,并与2007年版教科书进行对比。研究发现,2019年版教科书的实验活动探究层次处于层次1和层次2,学生行为要求为“观察”“记录实验现象”“回答与实验有关的问题”和“设计实验”。卡方检验表明,2019年版教科书和2007年版教科书“实验”栏目的实验活动探究层次分布比例和学生实验行为要求均存在显著性差异。     

初中化学(科学)启蒙教材中“实验”“插图”“科普知识”的比较分析*

我国大陆和台湾的化学(科学)教材在化学启蒙方面的内容编写有着各自的特点和优势,因此以我国大陆人教版初中《化学》与我国台湾康轩文教版《自然与生活科技》为例,通过问卷调查法与对比分析法,研究化学启蒙阶段的学生对待化学的态度以及海峡两岸教材中“实验”“插图”“科普知识”等3部分内容的设置差异。结果表明:(1)化学实验是启蒙阶段学生对化学感兴趣的起始点,也是初接触时的难点,其中以我国台湾《自然与生活科技》教材中化学实验的探究性及层次性更深;(2)化学启蒙阶段教材中插图的科学性、清晰度以及精美程度对学生学习化学的兴趣和态度有较大影响;(3)化学教材中的模型图实物化有助于学生拨云见日,了解化学的真实模样。     

《化学教育》问题解决研究论文的统计分析

以《化学教育》期刊为研究对象,采用上海师范大学图书馆的“中文期刊数据库”进行关键词检索和查阅原始杂志相结合的方法,主要从论文的数量、研究方法、研究内容、研究目的和作者所在地区等5个方面对1999-2010年近11年间有关化学问题解决研究的论文进行统计分析和评价,从另一侧面探讨我国化学学科问题解决研究的发展趋势、水平、存在的问题。     

高中化学教科书中“潜台词”的研究*

以人教版高中《化学1》《化学2》为研究对象,将化学教科书中“潜台词”分为文字中的“潜台词”、表格中的“潜台词”、插图中的“潜台词”3类,对教科书中“潜台词”的作用与功能、类型与呈现知识的方式进行了说明与分析。     

国内化学教育领域调查研究的内容分析与品质考察

选取化学教育领域核心期刊《化学教育》和《化学教学》2011-2016年的180篇调查研究类文献为样本,分析了研究的现状和趋势,并运用“调查类文献品质考察工具”对调查类文献品质进行了考察。研究发现,调查类研究数量呈下降趋势;研究主题以化学学习、教师教育、化学教学为主;调查对象主要是中学生和在职教师;作者群体约半数来自高等学校。研究品质方面,虽然研究品质逐年提高,但整体研究品质仍不容乐观,主要问题在于缺乏信度和效度的直接证据,数据分析处理方式单一,以及文献探讨不足。     

“证据推理”在高考化学试题(全国卷)中的考查特点*

基于《普通高中化学课程标准(2017年版2020年修订)》提出的化学学科核心素养中“证据推理”的内涵及相关研究,将“证据推理”化学学科核心素养进一步解构为 “证据解读”“证据与结论的关系”“证据评估”等3个要素,并将证据按其呈现形式划分为反应机理、实验数据、工艺流程和实验方案等4种类型,在此基础上构建了“证据推理”视角下的试题分析框架,并以近5年高考化学试题(全国卷)为研究对象,总结其考查特点与规律,进而为改进化学教学提出相关建议。     

《化学教育》“调查报告”栏目文献的统计分析——基于1980-2008年的载文研究

以<化学教育>"调查报告"栏目29年来的载文为研究对象,采用系统查阅年度总目录与阅读原始文献相结合的方法,从载文的年度分布、内容、调查研究类型、作者等4方面进行统计分析,在一定程度上反映了改革开放以来关于我国化学教育的调查研究发展历程、现状及趋势,并针对其存在的问题提出了建议.     

中学化学实验改进研究的现状与思考

以3种中等化学教育类期刊《化学教育》《化学教学》和《中学化学教学参考》为研究对象，对近5年来期刊中有关中学化学实验改进研究的文献进行研究，对论文的数量、作者地区分布、作者单位、作者合作情况、研究内容、实验改进方法等进行统计分析，探讨我国中学化学实验改进研究的发展趋势及存在的问题。     

“素养为本”的化学课堂教学设计研究的特征与启示*——基于CNKI 253篇文献的知识图谱研究

利用CiteSpace可视化文献计量分析软件,对2016年以来,我国化学教育教学领域最具影响力的3本学术期刊《化学教育》《化学教学》和《中学化学教学参考》中“素养为本”的化学课堂教学设计相关文献进行统计分析,探析其研究热点和发展趋势,以期为后续“素养为本”的化学课堂教学设计提供有益的参考。     

Evaluation of thermodynamic and kinetic stability of CuAlO<Subscript>2</Subscript> and CuGaO<Subscript>2</Subscript>

Thermodynamic and kinetic stabilities of CuAlO₂ and CuGaO₂ have been evaluated by using thermogravimetry and thermodynamic calculations. It has been revealed that CuAlO₂ and CuGaO₂ are not thermodynamically stable in air below 800 °C and 1,200 °C, respectively, and that the oxidation reaction, 4CuMO₂ + O₂ → 2CuO + 2CuM₂O₄ (M = Al, Ga), should occur if the reaction kinetics are high enough. However, rate constants and activation energies indicated slow kinetics of the oxidation reaction, showing kinetic stability of CuMO₂ even under some thermodynamically unstable temperatures and atmospheres. It was also concluded that CuAlO₂ showed higher thermodynamic and kinetic stability than CuGaO₂.     

Heat capacities and absolute entropies of UTi<Subscript>2</Subscript>O<Subscript>6</Subscript> and CeTi<Subscript>2</Subscript>O<Subscript>6</Subscript>

Summary As part of a larger study of the physical properties of potential ceramic hosts for nuclear wastes, we report the molar heat capacity of brannerite (UTi₂O₆) and its cerium analog (CeTi₂O₆) from 10 to 400 K using an adiabatic calorimeter. At 298.15 K the standard molar heat capacities are (179.46±0.18) J K^-1 mol^-1 for UTi₂O₆ and (172.78±0.17) J K^-1 mol^-1 for CeTi₂O₆. Entropies were calculated from smooth fits of the experimental data and were found to be (175.56±0.35) J K^-1 mol^-1 and (171.63±0.34) J K^-1 mol^-1 for UTi₂O₆ and CeTi₂O₆, respectively. Using these entropies and enthalpy of formation data reported in the literature, Gibb’s free energies of formation from the elements and constituent oxides were calculated. Standard free energies of formation from the elements are (-2814.7±5.6) kJ mol^-1 for UTi₂O₆ and (-2786.3±5.6) kJ mol^-1 for CeTi₂O₆. The free energy of formation from the oxides at T=298.15 K are (-5.31±0.01) kJ mol^-1 and (15.88±0.03) kJ mol^-1 for UTi₂O₆ and CeTi₂O₆, respectively.     

Interatomic interactions and electronic structure of NbSe<Subscript>2</Subscript> and Nb<Subscript>1.25</Subscript>Se<Subscript>2</Subscript> nanotubes

Atomic models of achiral NbSe₂ nanotubes are suggested. Band structure calculations have been performed to investigate the electronic structure and determine the parameters of interatomic interactions. The distribution of the density of states and pair bond occupancies of NbSe₂ nanotubes are analyzed in relation to the type of the atomic configuration and the tube diameter; the results are compared with the band structure of the 2H-NbSe₂ crystal. Calculations have been carried out on hypothetical superstoichiometric nanotubes with a formal composition Nb_1.25Se₂ as possible quasi-one-dimensional nanoforms of autointercalated niobium diselenide.Original Russian Text Copyright © 2004 by A. N. Enyashin, V. V. Ivanovskaya, I. R. Shein, Yu. N. Makurin, N. I. Medvedeva, A. A. Sofronov, and A. L. IvanovskiiTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 579–588, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.     

Generation and IR spectra of ionic and molecular complexes of aluminum chloride with <Emphasis Type="Italic">tert</Emphasis>- and <Emphasis Type="Italic">sec</Emphasis>-butyl chlorides

Sec-butyl and tert-butyl cations were first stabilized upon cocondensation of aluminum chloride and haloalkanes (2-chlorobutane and 2-chloro-2-methylpropane, respectively) and their IR spectra and thermal stability investigated. Aluminum chloride anions participating in stabilization of carbenium ions were revealed. Ionic complexes and both 1:1 and 2:1 molecular complexes of reagents were detected and their IR spectra studied. Quantum-chemical calculations at the PBE level of density functional theory with inclusion of electron correlation were employed to optimize the geometric parameters and to determine the vibrational frequencies of aluminum chloride, butyl chlorides, and their complexes of various compositions. The structures of the associates observed were determined on the basis of comparison of the experimental and calculated vibrational spectra.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 147–155, January, 2005.     

Synthesis and characterization of Mn-, La-Mn- and La-Ca-Mn-citrates as precursors for LaMnO<Subscript>3</Subscript> and La<Subscript>1−x</Subscript>Ca<Subscript>x</Subscript>MnO<Subscript>3</Subscript>

Mn-, LaMn- and LaCaMn-citrates were synthesized at 60–120°C in ethylene glycol medium using chlorides or nitrates as metal sources. Their composition, IR spectra and thermal decomposition were studied. Equimolar La/Mn ratio has been established in the complex, prepared from chloride solution with the same initial composition of the metals. In the isolated three-metallic complex the molar ratio of the metals deviates from the composition in the initial solution. The final products of the heating of Mn- and mixed-metal LaMn-citrates at 1000°C are phase-homogeneous Mn₃O₄ (hausmannite) and LaMnO₃ respectively. Parasitic phase(s) are observed in La_xCa_1−xMn_yO₃, produced from LaCaMn-citrate.     

Chemical Composition and <em>in Vitro</em> Evaluation of the Antioxidant and Antimicrobial Activities of <em>Eucalyptus gillii </em>Essential Oil and Extracts<em></em>

In this study, essential oil and various extracts (hexane, petroleum ether, acetone, ethanol, methanol and water) of Eucalyptus gilii were screened for their chemical composition, antimicrobial and antioxidant activities. The essential oil chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID), respectively. Thirty four compounds were identified, corresponding to 99.5% of the total essential oil. Tannins [104.9-251.3 g catechin equivalent (CE)/Kg dry mass], flavonoids [3.3-34.3 g quercetin equivalent (QE)/Kg dry mass], phenolics [4.7-216.6 g gallic acid equivalent (GAE)/Kg dry mass] and anthocyannins [1.2-45.3 mg cyanidin-3-glucoside equivalent (C3GE)/Kg dry mass] of various extracts were investigated. Free radical scavenging capacity of all samples was determinedt. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the IC₅₀ of essential oil was 163.5 ± 10.7 mg/L and in the 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS) assay, it was 94.7 ± 7.1 mg/L. Among the various extracts, the water extract showed the best result (IC₅₀ = 11.4 ± 0.6 mg/L) in the DPPH assay which was comparable to vitamin C (IC₅₀ = 4.4 ± 0.2 mg/L). The antimicrobial activities were evaluated against different bacterial and fungal strains. Gram positive bacteria were found to be more sensitive to the essential oil and extracts than Gram negative ones. Anthocyanins seem to have a major effect on the growth of Bacillus subtilis (R² = 0.79). A significant antifungal activity was observed against the yeast and fungi. Correlations between chemical composition and antioxidant activities were studied and R² values were about 0.96 for the effect of phenolics on the DPPH assay.     

Methyl­malon­amide and ethyl­malon­amide

In the title compounds, C₄H₈N₂O₂, (I), and C₅H₁₀N₂O₂, (II), respectively, the amide groups are rotated out of the central C—C—C plane by ca 76° in (I) and by 70–73° in (II). Compound (I) has crystallographic mirror symmetry perpendicular to the molecular plane.     

Bleaching of solutions of chlorophylls <Emphasis Type="Italic">a</Emphasis> and <Emphasis Type="Italic">b</Emphasis> with blue and red light

The dependences of the reaction rate constant for bleaching of solutions of chlorophyll under the action of light with a wavelength of 434 and 670 on the type of solvent and additives (O₂, H₂O, HCl, and anthocyanins) have been studied.     

Synthesis and structure of allylated derivatives of fullerenes C<Subscript>60</Subscript> and C<Subscript>70</Subscript>

New chromatographically pure monoand hexamethanofullerenes C₆₀ and C₇₀ containing active allylic groups were synthesized by Bingel—Hirsch reaction. These compounds are promising for the studies of biological activity, as well as for obtaining on their basis new fullerenecontaining materials. The purity and composition of the synthesized compounds were confirmed by MALDI-TOF mass spectrometry and HPLC, their structure was established by ¹H and ¹³C NMR spectroscopy and X-ray diffraction.     

Separation and purification of <Superscript>249</Superscript>Cf and <Superscript>245</Superscript>Cm

There is a need to provide radioactivity standards of the higher actinides in support of both decommissioning and remediation activities as well as routine environmental analysis. In the case ²⁴⁹Cf, this will provide a useful calibration nuclide for both α-and γ-spectrometry as well as improving knowledge of the decay scheme for this nuclide. There is anecdotal evidence to suggest that the chemical yield of americium and curium may differ in radiochemical analysis. Thus, a chemical yield tracer of ²⁴⁵Cm may help to resolve this issue and will be suitable for both, suitable for use as a chemical yield tracer for both α-particle spectrometry and mass spectrometry. An aged source of ²⁴⁹Cf was used as the source material for the separation of these two nuclides by cation-exchange, using 2-hydroxy-2-methyl-propanoic acid at controlled pH as an eluant, ²⁴⁹Cf being eluted before the ²⁴⁵Cm daughter. The purity of both nuclides was measured by γ-ray spectrometry.