共查询到20条相似文献,搜索用时 109 毫秒
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一、中学化学实验教学自成系统以实验为基础的化学学科特征,决定了化学实验教学系统是化学教育系统中的主要子系统,应有其能决定性地影响化学教育质量的教育目标和教学结构。中学化学实验的教育目标,在认知领域中可概括为探索和形成、使用和评价化学理论与技术知识:在操作领域中可概括为掌握实验基本操作技能和化学技术基础:在情感领域中可概括为形成科学观点,提高心理素质。中学化学实验的教育目标决定了它的教学结构。 相似文献
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实验既是化学学科发展的基础,又是化学教学的有效手段,以实验为基础开展探究教学是化学教学的方向之一。以实验目的、实验原理、实验装置、实验步骤、实验现象和实验结论等实验方案的要素为切入点为实验探究教学创造更多的实践途径,从而实现基于实验的探究教学在理念、思维和操作层面的发展。 相似文献
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微型化实验由于较好的教学效果和显著的经济与社会效益,成为当前化学实验教学改革的方向之一。基于此,从实验仪器装置、实验条件、实验方法、实验内容、创新性、与探究教学的整合这五个方面对微型化学实验在基础化学实验教学中的研究进行了总结,从而为微型化学实验应用于基础化学实验教学提供参考。 相似文献
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深圳市宝安区儿童头发中微量元素含量与儿童眼病关系的研究 总被引:2,自引:1,他引:2
李海鸥 《广东微量元素科学》2003,10(12):32-34
通过对2001~2003年深圳市宝安区独生子女(0~14岁)近20000例体检情况统计,结合测定头发中微量元素锌、铁、铜、钙、锰、硒六种元素含量,对照健康人微量元素测定,发现缺锌、缺铜、缺硒儿童较健康儿童更易患近视,这一结论与相关报道一致。 相似文献
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We designed and synthesized new anion receptors 1, 2, and 3, which have different N-H polarity. According to their N-H polarities, these receptors showed different selectivities for the anions they were interacting with. The difference of selectivity could be easily recognized from their color change during recognition events. Therefore, fine tuning of receptor polarity could be a good strategy for the designing of a selective anion receptor and made it possible to develop a selective naked eye anion receptor. 相似文献
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This review covers the concepts of photonic crystal (PhC) and its usage for the sensing of environmental pollutants. PhCs are composed of periodic and ordered nanostructures which can manipulate the diffraction or reflection of light propagation through the structures. If the light spectra locate in the visible range, the color of materials can be observed by naked eye. The optical properties of PhCs are determined by the lattice constant of the crystal or by the refractive index contrast between the colloids and the surrounding medium. Based on these features, responsive PhCs can be designed to detect the environmental pollutants. In this review, we primarily described the photonic crystals for the sensing of volatile organic compounds (VOCs), organophosphates (OPs), heavy metal ions and endocrine disrupting chemicals (EDCs), and these sensors exhibited excellent sensitivity and are promising for the on-site monitoring of pollutants. 相似文献
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Cheng-Chun Peng Colin Cerretani Richard J. Braun C.J. Radke 《Advances in colloid and interface science》2014
Tear-film instability is widely believed to be a signature of eye health. When an interblink is prolonged, randomly distributed ruptures occur in the tear film. “Black spots” and/or “black streaks” appear in 15 to 40 s for normal individuals. For people who suffer from dry eye, tear-film breakup time (BUT) is typically less than a few seconds. To date, however, there is no satisfactory quantitative explanation for the origin of tear rupture. 相似文献
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以氧化还原反应相关试题作为测试材料,采用眼动追踪技术对12名高一学生进行3(学业水平)*3(试题难度)两因素混合实验,实验结束后进行追述性口语报告。结果表明,在氧化还原反应问题解决过程中学优生信息加工速度快、深度浅、难度小,采用正向加工和逆向排除结合的策略。学中生信息加工速度慢、深度深、难度大,采用正向加工策略。学困生轻易放弃,信息加工无效。随着问题难度的增大,学生信息加工速度变慢、深度变深、难度变大。 相似文献
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Colorimetric sensing strategies as a powerful point-of-care testing(POCT) tool have attracted significant interest in various chem/biosensing applications.Taking the excellent bare-eye-detectable signaling feature,nanozymes-based colorimetric sensors enable more potential applications and have been a new forefront in the colorimetric POCT analysis toward different target analytes.However,the low catalytic activity of nanozymes in most cases limits their practical application.Recent efforts demonstrate that the aggregation-induced nanozymes provide a general means to modulate nanozymes activity and enhance colorimetric sensing performances of some nanozymes-based colorimetric sensors.But there are few reports are explored to discuss and review such aggregation-induced nanozymes and their colorimetric sensing applications.To highlight the advances and progress in aggregation-induced nanozymes based colorimetric assays,we herein summary the fundamentals,classify and applications of this newlydeveloping field,focusing on the aggregation-induced activity enhancement of nanozymes(AIAEnanozymes) with a significant "signal-on" feature and aggregation-induced activity inhibition of nanozymes(AIAI-nanozymes) with a dramatical "signal-of" characteristics.Finally,we also propose the current challenges and the future prospects on both AIAE-nanozymes and AIAI-nanozymes. 相似文献
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用气相色谱法测定眼药水中琥珀酸钠的含量。样品减压蒸干后,经酸化使琥珀酸钠变成琥珀酸,加入丙二酸进行衍生化反应,形成琥珀酸丁二酯和丙二酸丁二酯,以DEGS玻璃填充柱为色谱柱,用FID检测,进行气相色谱分析,结果令人满意。 相似文献
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Cyclodextrins in Eye Drop Formulations 总被引:1,自引:0,他引:1
Einar Stefánsson Thorsteinn Loftsson 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):23-27
Ideally, eye drop formulations are aqueous solutions. Many drugs that are useful in topical application to the eye are not sufficiently water soluble to be dissolved in simple aqueous solutions. This problem is approached through hydrophilic prodrugs, suspensions, lipid based solutions and excipients such as cyclodextrins. Cyclodextrins can be used to form aqueous eye drop solutions with lipophilic drugs, such as steroids. The cyclodextrins increase the water solubility of the drug, enhance drug absorption into the eye, improve aqueous stability and reduce local irritation. Cyclodextrins are useful excipients in eye drop formulations of various ophthalmic drugs, including steroids of any kind, carbonic anhydrase inhibitors, pilocarpine and cyclosporins. Their use in ophthalmology has already begun and it is likely to expand the selection of drugs available as eye drops. In this paper we review the use of cyclodextrins in eye drop formulations. The use of cyclodextrins to formulate dexamethasone eye drops is an example of their usefulness. Cyclodextrins have been used to formulate eye drops containing corticosteroids, such as dexamethasone, with concentration and ocular absorption, which in human and animal studies is many fold that seen with presently available formulations. Such formulations offer the possibility of once a day application of corticosteroid eye drops after eye surgery, and more intensive topical steroid treatment in severe inflammation. 相似文献
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W. Karcher 《SAR and QSAR in environmental research》2013,24(3):167-169
Abstract Cluster significance analysis is a tool that allows the identification of ‘embedded clusters’ in QSAR datasets. It is successfully applied to an eye irritation data set to show that these data are indeed asymmetric. The method identifies five parameters that form an embedded cluster of eye irritants amongst non irritants, although full separation is not achieved. This method has considerable potential to identify potential non-linearity in toxicology data sets and for parameter reduction. It is shown also that this can be obtained relatively quickly with an analysis performed on 100,000 subsets containing the same information as an analysis on 1,000,000 subsets. 相似文献