小学科学教材中化学实验设计可行性研究

小学科学课融合化学等多学科知识于一体, 化学知识的讲授主要以实验为主, 化学实验设计的可行性是实验能否顺利实施及小学生对化学知识能否有效获取的一个重要环节, 因此小学科学教材呈现出的化学实验设计直接影响小学科学教师的教育教学实践活动。主要分析了现有小学科学教材中的化学实验设计的可行性, 为今后的小学科学教学及教材修订提出了建议。     

五年制专科小学教育专业的教学大纲和教材与小学科学课程标准和教材的对比

对小学科学课程标准与五年制专科小学教育专业“科学·化学”教学大纲中对化学知识内容的要求,以及小学《科学》和高等专科学校《科学·化学》教材中涉及的化学知识内容进行了对比。同时就五年制专科层次小学教育专业化学课程存在的问题进行了讨论,并提出了选择合适的课程教学内容、加强化学实验和化学教材建设、建立理论课程和实验教学新体系模块等建议。     

小学科学化学实验教学中的注意分散研究

小学科学中的化学实验是学生获取科学认识的重要方式。经观察研究发现,小学化学实验教学中存在明显的注意分散现象。实验教学过程中的注意分散问题会影响学生科学探究能力的培养,阻碍学生科学知识的获取和科学概念的形成。通过观察小学科学的课堂以及分析小学科学2012-2018年的优质课视频,根据课堂中注意分散的不同现象,划分了注意分散的类型;结合教育目标分类学、认知负荷理论及注意资源限制理论,剖析了小学化学实验教学中注意分散的原因,提出解决小学化学实验教学中注意分散问题的对策。     

发挥小学化学实验教学功能的策略初探

在小学科学教学实践中,化学实验具有特殊的教学功能。小学科学实验设计的合理与否,以及小学科学教师对实验教学功能的认识和落实程度,会最终影响小学科学实验的教学效果。本文主要从小学科学实验的设计和小学科学教师2个方面出发,在对各版本小学科学教材化学实验和现有教学情况分析的基础上,对实验设计提出整体的改进建议;同时,要求小学科学教师应该结合教学资源和学生基础,重视实验情境化和科学实验方法化,充分发挥小学化学实验的教学功能。     

浅谈运用性实验在化学教学中的作用

掌握知识是为了运用。化学是一门以实验为基础的科学,化学知识源于实验,又应当在实验中得到发展。学生的认识过程是在教师指导下完成的特殊的认识过程,它也应当遵循这一规律。因此,我们在教学中不但应当用实验作为使学生探索、发现知识的手段,而且应当用实验为学生提供一个模拟实际的情境,使学生获得的化学知识能在实验中运用。权且称这种实验为“运用性实验”,按其思维过程的主要特征,又可分为分析型和综合型两类。     

高师无机化学实验教学的改革与学生综合能力的培养

化学是一门实验科学,无机化学实验又是高师化学系学生学习的第一门专业实验课程,它关系到学生能否掌握无机化学知识和有关技能,能否有效地掌握科学思维方法、养成科学精神和品质,因此有必要加强和改进无机化学实验课程的教学。根据学科的特点和师范性的要求,高师化学教育改革必须以进取和创新为主导,因材施教,教书育人,重视发掘人的潜能,重视素质教育。     

化学实验“三三三”翻转教学模式的探索与实践*

针对当前化学实验翻转课堂教学模式中存在的不足,依托“云班课”,重构了以学生为中心的化学实验“三三三”翻转教学新模式,即将实验教学划分为“三个课堂”:自学课堂、理论课堂和实验课堂等;理论课堂里包含“三个环节”:个人汇报、小组活动和测试点评等;学习效果评判有“三个评价”:自学评价、参与评价和动手评价等。以有机化学实验中“环己烯的合成”为例,采用该新的教学模式开展了教学活动,整个教学过程不仅体现了“以学定教、学生为中心”的教学理念,而且也能发挥出线下传统课堂的优势,实现了将“知识内化”的时间拉长,达到对学生线上自学“知识传授”掌握度的有力检验的目的,更有时间和空间进行课程思政元素的挖掘与融入,完成在知识传播中实现对学生的价值引领。     

"知识为线一方法为纲":基于化学基本原理的探究教学新探

课堂中有关化学基本原理的内容通常不易开展探究教学.在"化学反应速率影响因素的探究"课题的教学设计与实践过程中,采用"知识为线-方法为纲"的设计思路,以化学反应速率影响因素的相关知识为线索承载科学探究方法,将课堂中探究教学的焦点从化学知识延伸至科学方法,较好地凸显了科学探究方法教育.在此基础上,进一步挖掘科学探究方法的化...     

在化学方面培养学生实践知识与技能的教学法

本文的目的是想利用现有教学法文献及自己多年来在中学工作的经验,帮助教师在日常工作中培养学生的实践知识与技能。实践知识与技能的意义学生能深刻了解而又牢固掌握化学知识的主要条件之一是在教学过程中广泛运用化学实验,尤其是学生独立完成的实验。要在化学教学中完成综合技术教育,首先要使学生了解化学工业的基本科学知识。学生要了解化学工业的基本科学知识,则须对生产过程的基本化学反应及其进行的条件有较深刻的理解。这点主要在学生进行独立实验的过程中完成。为了在中学毕业后,使学生更好的参加工农业生产劳动,通过实验培养学生独立工作能力是完全必要的。     

改进化学实验工作的点滴体会

在进行化学教学过程中,我们首先必须掌握理论与实践相结合的原则,联系生产,联系实际,而且根据化学教学大纲指示:“化学是一门以实验为根据的科学”,因此,怎样按照规定来完成教学中的各项实验工作,这就是完成整个教学任务中的重要组成部分。过去,我们根据已经具备了的条件,努力克服困难,加强了实验工作,在1955年上半年开始,采用了“边讲边实验”的教学法,并结合教师演示实验及学生实习课来进行,对加深巩固学生知识,提高教学质量,起了极大的作用,最近,     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。