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以《化学1》"研究物质的实验方法"为例,分析了初高中化学实验教学的差异性,提出了要实现初高中化学实验教学的有效衔接,引导学生形成良好的实验习惯,根据学生的实际水平选择合理的教学方法,把握衔接点的差异性,引导学生突破思维障碍,加强实验思想观念的渗透等教学策略。 相似文献
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以POE教学策略组织教学,尝试用比较思维方法学习碳酸钠、碳酸氢钠的性质,并设计多组实验比较碳酸钠、碳酸氢钠的结构、性质等,以期学生学会用比较思维和化学科学研究的一般步骤。 相似文献
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以氯水的教学为案例,运用三重表征方式多元角度认识和理解物质,并用思维导图直观表示三重表征之间的联系。研究结果表明,SOLO分类理论可有效指导教师确定学生的学习最近发展区及有效的教学策略;运用思维导图可直观表示化学知识三重表征之间的逻辑关系,促进学生建构起三重表征的有机整体关系,加速以符号表征为桥梁进行三重表征之间的互译转换,促使学生将多点知识结构发展为关联知识结构、抽象拓展结构水平。因此,在教学中应用思维导图建构化学三重表征的整体关系,有利于提高学生学习结果的质量。 相似文献
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基于学生在学习难溶电解质溶解平衡中的问题,从实际案例出发深入分析了问题产生的原因,通过对“难溶电解质溶解平衡”知识在现象、概念、方法、价值4个水平和事实性、概念性、方法性和价值性4个层面的解读,提出了通过实验理解难溶电解质的溶解平衡、依据平衡常数解读溶液中的定量关系、建构浓度变化对平衡影响的思维模式这3种解决学生学习问题的具体教学策略。 相似文献
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基于学生在学习难溶电解质溶解平衡中的问题,从实际案例出发深入分析了问题产生的原因,通过对“难溶电解质溶解平衡”知识在现象、概念、方法、价值4个水平和事实性、概念性、方法性和价值性4个层面的解读,提出了通过实验理解难溶电解质的溶解平衡、依据平衡常数解读溶液中的定量关系、建构浓度变化对平衡影响的思维模式这3种解决学生学习问题的具体教学策略. 相似文献
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第10届大学生化学实验竞赛在北京化工大学成功举行,大学生化学实验竞赛能检验学生掌握化学实验技能和操作水平的情况,促进学生更好地了解和掌握实验仪器,锻炼学生的动手能力和创新意识,培养学生严谨科学的态度。通过"北京市大学生化学实验竞赛"这个平台,高校之间更好地交流了化学实验教学的经验,并以此为契机促进化学实验教学的改革,提高化学实验教学水平。 相似文献
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在化学实验教学中,结合现代教育理论,探讨了“阶梯式”、“精深式”、“激趣式”和“创新式”系列化学实验的设计,以支持和促进学生的学习,努力构建一种从实验中连贯建构知识意义的教学过程,提高化学实验教学的有效性。 相似文献
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Kerstin Schulze‐Matthi Jürgen Bendig Petra Neubauer Burkhard Ziemer 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):e257-e258
The bonding geometry of sulfur in the cations of the title compounds, C8H11S+·CF3SO3? and C13H13S+·CF3SO3?, respectively, is similar and is independent of the ratio of the Me/Ph substituents. As expected, in both cations, the S—Ph bonds are somewhat shorter than the S—Me bonds. In both crystal structures, the interaction between cations and anions is similar. 相似文献
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Russell G. Baughman Kenneth L. Martin Rajendra K. Singh James O. Stoffer 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o103-o106
In 2,4‐dihydroxybenzaldehyde 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate {or 4‐[(2,4‐dinitrophenyl)hydrazonomethyl]benzene‐1,3‐diol N,N‐dimethylformamide solvate}, C13H10N4O6·C3H7NO, (X), 2,4‐dihydroxyacetophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylformamide solvate (or 4‐{1‐[(2,4‐dinitrophenyl)hydrazono]ethyl}benzene‐1,3‐diol N,N‐dimethylformamide solvate), C14H12N4O6·C3H7NO, (XI), and 2,4‐dihydroxybenzophenone 2,4‐dinitrophenylhydrazone N,N‐dimethylacetamide solvate (or 4‐{[(2,4‐dinitrophenyl)hydrazono]phenylmethyl}benzene‐1,3‐diol N,N‐dimethylacetamide solvate), C19H14N4O6·C4H9NO, (XII), the molecules all lack a center of symmetry, crystallize in centrosymmetric space groups and have been observed to exhibit non‐linear optical activity. In each case, the hydrazone skeleton is fairly planar, facilitated by the presence of two intramolecular hydrogen bonds and some partial N—N double‐bond character. Each molecule is hydrogen bonded to one solvent molecule. 相似文献
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Ming‐Liang Tong Shao‐Liang Zheng Xiao‐Ming Chen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):960-962
The title compound, poly[[diaquadibromocadmium‐μ‐(1,3,5,7‐tetraazatricyclo[3.3.1.13,7]decane‐N1:N5)‐aquacadmium‐di‐μ‐bromo‐aquacadmium‐μ‐(1,3,5,7‐tetraazatricyclo[3.3.1.13,7]decane‐N1:N5)‐di‐μ‐bromo] dihydrate], [Cd3Br6(C6H12N4)2(H2O)4]·2H2O, is made up of two‐dimensional neutral rectangular coordination layers. Each rectangular subunit is enclosed by a pair of Cd3(μ2‐Br)6(H2O)3 fragments and a pair of (μ2‐hmt)Cd(H2O)2Br2(μ2‐hmt) fragments as sides (hmt is hexamethylenetetramine). The unique CdII atom in the Cd2Br2 ring in the Cd3(μ2‐Br)6(H2O)3 fragment is in a slightly distorted octahedral CdNOBr4 geometry, surrounded by one hmt ligand [2.433 (5) Å], one aqua ligand [2.273 (4) Å] and four Br atoms [2.6409 (11)–3.0270 (14) Å]. The CdII atom in the (μ2‐hmt)Cd(H2O)2Br2(μ2‐hmt) fragment lies on an inversion center and is in a highly distorted octahedral CdN2O2Br2 geometry, surrounded by two trans‐related N atoms of two hmt ligands [2.479 (5) Å], two trans‐related aqua ligands [2.294 (4) Å] and two trans‐related Br atoms [2.6755 (12) Å]. Adjacent two‐dimensional coordination sheets are connected into a three‐dimensional network by hydrogen bonds involving lattice water molecules, and the aqua, bromo and hmt ligands belonging to different layers. 相似文献
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Y. Akishige H. Shigematsu T. Tojo H. Kawaji T. Atake 《Journal of Thermal Analysis and Calorimetry》2005,81(3):537-540
Summary Specific heats on the single crystals of Sr2Nb2O7, Sr2Ta2O7 and (Sr1-xBax)2Nb2O7 were measured in a wide temperature range of 2-600 K. Heat anomalies of a λ-type were observed at the incommensurate phase transition of TINC (=495 K) on Sr2Nb2O7 and at the super-lattice phase transition of TSL (=443 K) on Sr2Ta2O7; the transition enthalpies and the transition entropies were estimated. Furthermore, a small heat anomaly was observed at the low temperature ferroelectric phase transition of TLOW (=95 K) on Sr2Nb2O7. The transition temperature TLOW decreases with increasing Ba content x and it vanishes for samples of x>2%. 相似文献
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A. V. Egorysheva V. D. Volodin T. Milenov P. Rafailov V. M. Skorikov T. D. Dudkina 《Russian Journal of Inorganic Chemistry》2010,55(11):1810-1817
A physicochemical study of glasses based on the MO-Bi2O3-B2O3 and SrO-Bi2O3-B2O3 systems was performed. Glass formation regions were found. The structural and optical properties, as well as the thermal
behavior of the glasses, were studied. 相似文献
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Jem‐Mau Lo Golam Mostafa Ling‐Yin Chang Fen‐Ling Liao Tian‐Huey Lu 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(4):o276-o277
The title compound, C10H18N2S2, acts as an important precursor for the synthesis of the pharmaceutically important diaminedithiol ligand system. The molecule has a local twofold axis and the arrangement of the S2N2 donor atoms in the macrocycle is anticlinal. 相似文献
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S. Shanmuga Sundara Raj Hoong‐Kun Fun Zhong‐Lin Lu Wen Xiao Xiao‐Yang Gong Chang‐Ming Gen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1015-1016
The whole molecule of the title compound, C19H14N4O2, is essentially planar, with a highly conjugated π system. In the crystal, the molecules are packed as chains along the [011] direction connected by O—H?N intermolecular hydrogen bonds. 相似文献
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Hai-Rong Guo Yuan Gao Ai-Dong Li Zhong Yan Di Wu 《Journal of Sol-Gel Science and Technology》2008,45(3):315-318
Pb0.56Sr0.44Zr0.52Ti0.48O3 (PSZT) inverse opal photonic crystals (PCs) have been synthesized by a process of self-assembly in combination with a sol–gel
procedure. PSZT inverse opals show pure perovskite structure with good orders in three dimensions. The evident photonic band
gaps have been observed in the transmittance spectra with a blue-shift phenomenon due to the decrease of opal template periods.
PSZT inverse opals also exhibit the reflection peaks in basic agreement with the calculated results. This three-dimensional
(3D) ordered PSZT inverse opals have shown interesting optical characteristics and potential applications in optoelectronic
and photonic devices. 相似文献
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Hiroki Akutsu Jun‐ichi Yamada Shin'ichi Nakatsuji 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o433-o434
The title compound, C24H20P+·C9H17NO5S−, consists of an organic monovalent cation and an organic monovalent anion, the latter being derived from the TEMPO radical (TEMPO is 2,2,6,6‐tetramethylpiperidin‐1‐oxyl). Two inversion‐related anions interact via two –O—H⃛O—S– hydrogen bonds, forming a dimer in which there are no short contacts between the spin centres (–N—O) of the TEMPO(OH)SO3− anions. Furthermore, no significant magnetic interaction is observed between the dimers because the dimer is surrounded by cations. These results are consistent with the paramagnetic behaviour of the title salt. 相似文献