利用废弃泡沫塑料炼制燃料油气的研究性实验概述

化学是以实验为基础的自然学科.在中学化学活动课中,精心挑选具有探索性和实用性的实验课题,引导学生通过实验学习化学,是培养学生的实验探究能力和科学素养的重要途径.     

新课程背景下中学化学课堂教学实效性探究

开展了化学课堂教学实效性探究活动,通过不同备课组的研究课、教研组评课,授课教师根据集体评课进行教学反思,再进行组内交流,达成共识:要提高化学课堂教学的实效性必须做好3个方面的工作,即教学设计的科学性,教学策略的针对性,教学反思的及时性。要落实以人为本的理念,突出学生的主体地位,重视学生的体验,通过合作学习、探究学习等学习方式,促使学生理解和掌握化学知识,培养化学学习能力,提升科学素养。     

化学实验操作的实效性在中考试题中的有效考查

化学是一门以化学实验为基础的自然科学,化学实验试题主要从2个方面考查学生的化学科学素养,一是化学基本理论知识,二是化学实验操作。化学实验在中考题中占有很大的比例,从实验分值占大部分的客观性试题发展到现在分值占大部分的主观性试题,充分体现了考试主要是考查学生的思维能力,培养创新型的人才,而不是培养单纯凭记忆等解决问题的人才。在化学中考试题中如何真正体现学生的创新能力,这就要对化学实验操作的实效性进行有效的考查。     

饮用水实验——推荐一个针对非化学专业的生活化学实验

在非化学专业本科生生活化学实验课程中尝试开设饮用水实验,针对非化学专业学生的特点,重新设计实验的教学内容,通过贴近生活的实验内容,普及饮用水常识,培养学生的化学科学素养。     

高职院校学生化学科学素养培养的实践

生活中处处都有化学的身影,而在高职院校学生缺乏化学科学素养的背景下,介绍了在高职院校培养学生化学科学素养的必要性、途径及效果,以开设化学与生活公选课和科普活动的方式来培养高职学生化学科学素养。     

“金属与水反应规律的探究”教学设计及反思

在细致研究课标要求,比较不同版本教材在“金属与水反应”相关内容方面特点的基础上牢牢抓住化学核心知识的逻辑联系,以及核心知识所蕴涵的科学方法和化学思想;同时深入体会学生思维上的特点,并在教学设计中紧紧围绕知识的价值和学生的思维有逻辑地设计3个实验探究活动,着重注意对学生实验设计能力、观察能力、化学思想等方面的培养.     

基于化学基本观念构建的教科书设计

化学基本观念的构建影响着学生理解和应用化学知识的水平,对提高学生的科学素养具有重要价值。化学教科书的设计,应突出基本观念的构建,精选典型事实和核心概念,引导学生通过深层次的思维活动,促进知识的理解和观念构建。     

运用化学实验培养学生思维能力的探讨

课堂教学重在培养学生获取知识的方法和思维能力。探讨运用化学实验在课堂教学中培养学生的思维能力,其中包括迁移能力、收敛能力和释疑能力。     

有效突破习题讲评课提高化学教学质量

习题讲评是培养学生思维能力的重要途径,也是将学生从“题海”中解脱出来的一种有效途径。因此,抓好讲评课是提高化学教学质量的重要环节。本文提出了中学化学教学中如何提高讲评课的效率的具体思路,探讨了中学化学教学中抓好讲评课的方法步骤。     

安徽省农村初中化学实验教学现状的调查与思考

新课程将化学实验、科学探究作为化学课程改革的突破口,以培养学生的主动性和创新意识,提高学生的科学素养。自从新课程实施以来,农村中学化学实验教学情况如何,笔者通过对安徽省部分农村初中化学实验教学情况进行调查,探研问题存在的原因,并提出改进农村化学实验教学的几点建议。     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...