深入研究,促进少数民族学生化学学习的发展--畲族学生化学学习中非智力因素影响的调查与分析

论文对我国少数民族畲族学生进行了化学学习中非智力因素影响的调查与分析，从基本情况、化学学习动机、化学学习兴趣、化学学习习惯、化学学习意志等5个方面作了调查，对其特征和问题作了分析，提出了促进畲族学生化学学习发展的教学建议。     

中学生化学学习中精加工策略运用情况的调查分析

为了了解中学生在化学概念、化学用语、化学实验和化学计算等学习中精加工策略的运用情况,自编《化学学习中精加工策略运用情况问卷》,对江苏省赣榆县约2000名初三学生实施了调查与分析。提出在化学学习中提高学生精加工运用能力的教学建议是,加强比较法、笔记法、图示法、自我提问技术和联想记忆法等的学习指导。     

化学元素符号的巧妙教学

元素符号是学习化学的重要工具,是化学启蒙教育阶段的基础内容。在教学过程中如果采用死记硬背的方法,不仅加重了学生学业负担,而且严重影响学生学习化学的兴趣。利用巧妙的教学方法,既可以让学生轻松学化学,又能够培养学生的化学情感,对做好化学启蒙教育工作具有重要价值。     

运用科学阅读策略提高中学生的化学学习能力

科学阅读是科学学习的重要组成部分,将科学阅读策略应用于化学学习中,有利于学生对化学概念和化学知识的理解,有利于学生将新知识、新概念整合到自己的认知结构中,从而达到有意义的学习。     

理论指导实践化学实验教学模式的建构及实践

教材中演示实验或探究实验是针对某一个实验原理引导学生学习化学知识与实验操作技能、验证化学原理、训练科学思维.理论指导实践的化学实验教学模式旨在引导学生用学习过的化学知识和化学实验技能对未知领域进行综合性探索,学习新知,培养创新能力.     

城镇九年级学生化学学习现状调查与分析

通过对甘肃省陇南市城镇12所中学九年级学生化学学习现状的问卷调查,发现城镇九年级学生比较喜欢化学,但学习的动机、态度依然没有摆脱"应试"的惯性;学习习惯不良、方式方法欠缺.本文针对城镇九年级学生化学学习中普遍存在的问题,提出了应对的策略建议.     

初三化学教学要重视对学生进行学习目的和辩证唯物主义观点的教育

初三化学是中学生学习化学的开端.??教师要引导学生爱好化学,学好化学,可以通过多种途径.现就对学生进行学习目的教育和辩证唯物主义观点教育,谈点看法. 一、明确教学目的,结合实际对学生进行学习目的教育. 为了使学生学习化学有个良好的开端,必须让他们明确学习化学的目的和重要性,这一点非常重要. 在化学的第一堂课——绪言上,就要使学生清楚地知道:世界是物质的,化学研究的对象就是物质.所以,化学研究的范围是非常广泛的,化学与各门科学、工农业生产、国防建设和     

化学新课程教学中学生自主学习能力现状调查

自主学习是一种学生主动参与的、建构性的学习过程.自主学习能力是由内在学习动机、认知策略与元认知监控3个要素构成的.依据自主学习能力的构成及化学学科的特点,我们通过自编问卷测查化学新课程教学中学生自主学习能力的现状.结果显示,目前中学化学教学中学生自主学习能力水平较高,但随着年级的升高,学生的化学自主学习能力水平却呈现出显著降低的趋势.     

基于元认知理论的化学实验教学策略

实验是化学学习中获取知识、培养创新思维和实践能力的主要渠道。把元认知理论应用于化学实验教学实践来指导学生的学习可以解决“如何教会学生学习”及“如何提高元认知能力”等问题。对在化学实验教学中如何提高学生元认知水平提出了几点教学策略,以期元认知理论能与化学实验教学真正结合,对培养学生全面发展产生积极的影响。     

高一学生化学学科焦虑调查研究

学习焦虑是普遍存在于学生群体当中的一种负面心理情绪。以化学学科为切入点,选取108名高一学生为研究对象,从化学学习焦虑、化学应用焦虑、化学教师焦虑和化学考试焦虑4个维度深入分析高一学生化学学科焦虑问题。结果表明,高一学生化学学科焦虑整体处于较低水平,其中化学学习焦虑最高,化学考试焦虑最低;6名高焦虑个体中有5名均为男生,化学考试焦虑最严重,应该引起教师关注。     

XPS中Tougaard法本底扣除初探

介绍了XPS（X ray photoelectron spectroscopy）谱图中本底产生的机理以及Tougaard法本底扣除原理的简略推导过程,提出了可供编程的约化形式,使用VC语言编写程序试对不同样品（含金属、过渡金属及非金属）的谱图进行本底扣除,并与Shirley法、直线法本底扣除进行准确性的比较,提出了Tougaard方法试用于非金属粉末化合物样品的测试分析结果.     

The crystal and molecular structure of 5-N-methyl-β-d-arabinofurano[1′,2′:4,5]oxazolo-S-triazine-4,6-dione: Molecular modeling studies on the pattern of alkylation of β-D-arabinofurano[1′,2′:4,5]oxazolo-s-triazin-4-one-6-thione

The involvement of the 5′-hydroxyl group on β-D-arabinofurano[1′,2′:4,5]oxazolo-s-triazin-4-one-6-thione ( 1b ), to form an intramolecular covalent adduct at C6, is postulated to explain the formation of almost equal amounts of 5-N-alkyl-β-D-arabinofurano[1′,2′:4,5]oxazolo-s-triazin-4-one-6-thione and 5-N-alkyl-β-D-arabinofurano[1′,2′:4,5]oxazolo-s-triazine-4,6-dione during alkylation of 1b . An X-ray crystallographic study was conducted on 5-N-methyl-β-D-arabinofurano[1′,2′:4,5]oxazolo-s-triazine-4,6-dione ( 2a ) and its solid state structure was established. This was compared to the energy minimized structure of the same compound that was generated by the molecular modeling program, MACROMODEL. Force field calculations (Allinger's MM2) on this structure and other intermediates lend support to the concept of formation of the intramolecular covalent adduct.     

A caution regarding the use of LAOCOON III for AA′BB′ spin systems

It has been found that LAOCOON III can fail to converge for some strongly coupled AA′BB′ spin systems unless trial coupling constants and chemical shifts within a few tenths of a Hz of the real parameters are used to initiate the iteration. This problem seemed linked to those spin systems possessing two or more pairs of energy levels which are nearly degenerate. In the cases where LAOCOON III failed, the program NMRENIT always yielded the correct, converged, iterative solution even with completely arbitrary starting parameters. The latter program also appears to accomplish a given number of iterations with an AA′BB′ system roughly three times as fast as the former program.     

催化动力学光度法对食品中痕量元素分析的研究进展

随着人们生活水平的不断提高,食品中痕量元素的含量越来越引起人们的关注.综述了近十年来催化动力学光度法在食品分析中对痕量元素进行测定的研究情况,并对催化动力学光度法在食品分析中的应用前景和研究方向进行了展望.     

The relationship between proton–proton NMR coupling constants and substituent electronegativities. II—conformational analysis of the sugar ring in nucleosides and nucleotides in solution using a generalized Karplus equation

The relationship between vicinal NMR proton–proton coupling constants and the pseudorotational properties of the sugar ring in nucleosides and nucleotides is reinvestigated. Compared with our earlier study several important improvements are introduced: first, a new empirical generalization of the classical Karplus equation is utilized, which allows an accurate correction for the effects of electronegativity and orientation of substituents on ³J(HH); second, empirical correlations between the parameters governing the conformation of β-D -furanosides (taken from an analysis of 178 crystal structures) were used to define proton–proton torsion angles as a function of the pseudorotation parameters P and Φ_m; and, third an iterative least-squares computer program was devised to obtain the best fit of the conformational parameters to the experimental coupling constants. NMR data for the sugar ring in the following compounds were taken from the literature and analysed: 3′,5′-cyclic nucleotides, a base-stacked ribonucleotide, 2′-anhydroarabinonucleosides, α-D -2′,2-O-cyclouridine, 2′- and 3′-aminosubstituted ribonucleosides, 2′- and 3′-deoxyribonucleosides. The present results confirm that the conformational properties found in the solid state are, on the whole, preserved in solution.     

Abilities in chemistry and possibilities of their diagnosing

Experimental results indicating the existence of special abilities in chemistry were reported, with chemistry interpreted as the science about substances and their transformations in accordance with the classical definition. It was shown that the key component of abilities in chemistry is a learner’s particular attitude to a substance. The possibilities of diagnosing schoolchildren’s abilities in chemistry were discussed. Promising directions for further psychological and educational research concerning the abilities in chemistry were considered.     

High resolution 1H NMR spectra of 2,2′-biquinoline

From analysis and refinement by the LAOCOON III program of the 220 MHz ¹H spectrum of 2,2′-biquinoline, recorded as a saturated solution in carbon disulphide, most derived chemical shifts and coupling constants are close to corresponding values in quinoline. However, H-3 is at 1.5 ppm lower field in 2,2′-biquinoline than in quinoline and the ortho-coupling ³J(34) in the heterocyclic ring is 0.5 Hz larger in 2,2′-biquinoline than in quinoline; fairly free rotation about the 2,2′ bond is inferred.     

开孔泡沫塑料率相关的拉伸力学性能及本构关系

以Ｌｅｄｅｒｍａｎ的工作为基础，通过假设基体材料服从Ｖｏｉｇｔ体描述的粘弹性本构关系，导出了开孔泡沫塑料受拉伸的率相关本构关系；在此基础上研究了泡沫塑料力学性质同应变、应变率和结构参数的关系．     

Isomeric bismaleimides and polyaspartimides

A study was conducted of the effects of meta-para isomerism on the synthesis and properties of aromatic bismaleimides and polyaspartimides. Three isomers, 3,3′-, 3,4′-, and 4,4′-diaminodiphenylmethanes (methylenedianilines), were used to prepare three isomeric bismaleimides. The bismaleimides then were reacted with their respective isomeric diamines in m-cresol solution to give a series of isomeric polyaspartimides. The properties of each of the isomeric series were measured and compared. Strong flexible films were solvent cast from the two polyaspartimides derived from the 3,4′- and 4,4′-diamines and their respective bismaleimides. Tensile properties of the films from the 3,4′-diamine/3,4′-bismaleimide combination polyaspartimide were equivalent to those from the 4,4′-diamine-derived polymer. That finding, together with that polymer's lower softening temperature and the nonmutagenic nature of the 3,4′-diamine monomer, suggested a potential usefulness for 3,4′-diaminodiphenylmethane as a replacement for 4,4′-diaminodiphenylmethane in addition polyimides.     

超拉伸聚乙烯的弹性模量和导热性能

为了揭示聚合物分子链伸展、取向的本征特性，发展了两个新的测量方法和实验装置，用于研究拉伸比高达２００的超拉伸聚乙烯凝胶的弹性性能、传热性能和聚合物结构的关系．应用激光脉冲热致超声法给出材料拉伸方向和横向杨氏模量，应用激光脉冲光热辐射法给出拉伸方向，横向和厚度方向的导热系数．随拉伸比λ的增加，轴向杨氏模量急剧的增加，而横向的仅有少许减小．导热系数具有相似的特性．本文发现当λ＝２００时，这种拉伸取向聚乙烯的轴向模量可达钢的８０％，而导热系数甚至可达２倍，直至成为热的良导体，这是由于在高拉伸比时形成了相当数量的伸展分子链构成的针状晶体———晶桥．本文提出晶桥作为短纤维分散相的取向聚合物的结构模型，对于超拉伸聚乙烯的上述特性可以进行统一描述和定量化分析，和实验结果很好符合．