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李梦雪  王祖浩 《化学教育》2020,41(23):81-86
为提高科学写作在实验教学中培养学生能力的目的,韩德(Brain Hand)等人开发了一种实验教学的科学写作工具--启发式科学写作(SWH),是一种建立在科学语言与课堂探究基础上的论证工具,通过“问题、方法、观察、观点、证据、评判、转变”的过程使得科学内容与语言活动联系起来,激发学生参与论证,从而促进学生对科学的理解。SWH在实验教学中的具体应用还受到多种因素的综合影响。SWH从“框架建构到具体实施”、从“理论到实践”的研究思路对其他教学或学习工具的研制具有启示性意义。  相似文献   

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聚合物科学进展   总被引:1,自引:0,他引:1  
董建华 《化学通报》2014,77(7):631-653
本文对2011~2013年我国高分子科学重要研究进展进行了综述。全文分为高分子化学、响应性高分子、高分子物理、高分子组装、超分子聚合物、光电功能聚合物、生物医用高分子、石墨烯/聚合物复合体系、聚合物杂化体系和高分子工程等10部分。近年我国内地学者发表的高分子领域研究论文总量跃居世界第一,论文引用数跃居第二,在诸多分支领域中学科发展水平大幅提高,达到或接近国际水平的研究成果快速增多,国际影响力逐年提高。我国高分子学者通过基础研究,为高分子工业技术水平提升和创新也做出了许多贡献。本文还对本学科前沿、发展趋势进行了介绍与展望。文中共引用了227篇参考文献。  相似文献   

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Benzotrithiophene (BTT) isomers were investigated using density functional theory (DFT) and time‐dependent DFT (TD‐DFT) with the aim to explore their structures, linear optical properties, vertical and adiabatic ionization potentials (IPv and IPa), electron affinities (EAv and EAa), and reorganization energies (λ). The computed bond lengths and bond angles at the B3LYP/6–311+G (d, p) level of theory are in good agreement with experimental crystal structures of the known BTTs. These molecules are planar with zero dihedral angle, making them an ideal backbone for high charge mobility. The UV–visible spectra of BTT isomers are in the range 280–360 nm. All BTT isomers have low hole/electron reorganization energies, which is the main characteristic of good hole/electron transporting materials, and these isomers in turn have potential applications in the field of organic materials.  相似文献   

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《中国化学会会志》2018,65(5):511-522
The dye regeneration step in a dye‐sensitized solar cell (DSSC) affects significantly the device efficiency. To be able to predict the dye regeneration efficiency by the electrolyte this paper provides a facile way to design high‐efficiency sensitizers for DSSC. This paper proposes, for the first time, a simple and ingenious way to identify the dye regeneration sites and their relative efficiencies when a specific electrolyte is used. Two steps are proposed to identify the dye regeneration sites and their relative regeneration efficiencies: (1) drawing all the resonance structures of the oxidized dye to determine the regeneration sites, and (2) choosing the most favored site for dye regeneration as the chemically softest (when the redox couple used is soft I/I3 pair) and the least spatially hindered site. The regeneration sites identified by the resonance structures are consistent with the β‐LUSO (β lowest unoccupied spin orbital) distribution, which is generally used for identifying the dye regeneration sites, calculated with DT‐DFT theory. The relative dye regeneration efficiency and photovoltaic performance of both ruthenium and metal‐free organic dyes predicted by the method reported here are supported by experimental data and the proposed dye regeneration mechanism. Several types of dye molecules are used to demonstrate the correctness of this new tool. This non‐classical tool, which uses the well‐known chemical knowledge of the resonance structure and hard–soft acid–base principle, without any computer calculation or physicochemical measurement, provides a very simple and powerful tool to quickly conceive high‐efficiency sensitizers for DSSCs.  相似文献   

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This perspective summarizes some interdisciplinary aspects of science and the relation to philosophy, also including the basic motivations and aims as they might be discussed with young scientists starting their careers and presented also in the form of a commencement speech. The contents of this speech were repeatedly discussed also with Jack Dunitz, who showed great interest in it, given his broad interests. The speech also referred to an earlier commencement speech by Jack Dunitz in 1989. In the introduction of our essay, we mention the early common history of science and humanities under the name of philosophy. This early history can be traced back to ancient Greek philosophy and the ‘academy’ of Platon in Athens with a history of more than 1000 years until closure in 529 AD, in modern times revived as the National Greek Academy in Athens in the 19th and 20th centuries. Other ‘academies’ in Europe started in the 17th century and had publications under various names involving ‘philosophy’ with a focus on what we call science (natural science) today. After about 1800 there was increasing fragmentation of the various fields of knowledge and philosophy was considered to be part of the modern ‘humanities’ quite separate from science, and the natural sciences were fragmented into physics, chemistry, biology etc., and even finer subdivisions. The essay also describes an effort at ETH Zurich, reintegrating the various subfields of science and also stressing an education of scientists and engineers in the humanities. The essay concludes with a discussion of several global risks for mankind and a scientific imperative to maintain life on Earth. The common aspects and the foundations of all sciences as fields of knowledge aiming for an understanding of the world around us and of human beings as part of it are discussed from various perspectives.  相似文献   

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Science in the modern world has long since become a factor in the production and reproduction of goods and a condition of life in this world. At the same time, however, it is more than this. Science has therefore become caught-up in an orientation crisis ever since scientists became aware that science can no longer be pursued merely for the sake of pure knowledge, the ideal from ancient times which had been held to be the proper guide for science in its quest for self-understanding. Is the philosopher of science capable of providing the researcher with an answer to the questions what it is he does, and whether or not he is deceiving himself in regard to science and his relationship to it? The philosophy of science has revealed areas which demonstrate that our science is never the smooth and elegant construction composed of observation, experiments, and mathematical and formal techniques which it has often been held to be. It is not the least of the modern philosophy of science's achievements to have demonstrated that science cannot teach man what he should do with it and its results.  相似文献   

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科学本质教学设计是科学本质教学实践的基础。本研究评估了35名职前科学教师的科学本质教学设计。数据源包括:科学本质教学设计、半结构化访谈、非正式访谈等多元数据。数据分析以“显性-反思性”教学为框架,分别从科学本质教学设计的目标设定、内容融合、情境创设、问题、讨论、反思等6个方面对职前科学教师的科学本质教学设计进行等级编码。研究结果表明,职前科学教师能够将科学本质作为认知性目标,挖掘课程材料中的科学本质内容,较好地设置科学本质的教学情境,但在具体实施科学本质教学设计的问题、讨论、反思时表现欠佳。这表明职前科学教师在将“显性-反思性”教学转化为具体的、实操层面的教学设计时仍然存在困难。  相似文献   

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科学本质作为国际科学教育的重要目标,受到越来越多的关注。但在实践中,教师缺少对科学本质的内涵和具体方面的深度理解,同时缺少有效的科学本质教学的相关指导。本文探讨了基础教育阶段科学本质的8个方面的具体内涵,阐明了科学本质的有效教学的特征,并以“原子结构”为例,为教师开展科学本质教学提供范例。  相似文献   

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魏壮伟 《化学教育》2007,28(4):10-12
帮助学生发展适当的科学本质观(VNOS)是科学教育的重要目标之一,而教师具有理想的科学本质观是实现这一目标的必要条件。有调查显示,现今理科教师的科学本质观基本处于较为朴素的水平,有待提高。鉴于此,本文在综合分析国内外相关研究的基础上,提出了一套符合中学理科教师实际情况的科学本质观发展策略。  相似文献   

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在介绍分技术的分类、色谱变体的基础上,对分离科学的发展动态进行了评述.  相似文献   

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Particularly-shaped silver nanostructures are successfully applied in many scientific fields, such as nanotechnology, catalysis, (nano)engineering, optoelectronics, and sensing. In recent years, the production of shape-controlled silver-based nanostructures and the knowledge around this topic has grown significantly. Hence, on the basis of the most recent results reported in the literature, a critical analysis around the driving forces behind the synthesis of such nanostructures are proposed herein, pointing out the important role of surface-regulating agents in driving crystalline growth by favoring (or opposing) development along specific directions. Additionally, growth mechanisms of the different morphologies considered here are discussed in depth, and critical points highlighted.  相似文献   

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Cyclodextrins (CDs) are a series of cyclic oligosaccharides formed by amylose under the action of CD glucosyltransferase that is produced by Bacillus. After being modified by polymerization, substitution and grafting, high molecular weight cyclodextrin polymers (pCDs) containing multiple CD units can be obtained. pCDs retain the internal hydrophobic-external hydrophilic cavity structure characteristic of CDs, while also possessing the stability of polymer. They are a class of functional polymer materials with strong development potential and have been applied in many fields. This review introduces the research progress of pCDs, including the synthesis of pCDs and their applications in analytical separation science, materials science, and biomedicine.  相似文献   

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按测试方法分类,包括电化学分析方法、毛细管电泳法,分子活化分析法,计算机模拟以及以气相色谱、高效液相色谱,流动注射等为基础的联用技术,对近lO年来广泛应用于环境与生命科学的国内外元素形态分析研究进展进行了综述。  相似文献   

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A number of novel carbon materials whose unique properties fit them for many uses have recently been developed. Pyrolytic graphites are excellent conductors of heat and electricity parallel to the surface, whereas they are semiconductors perpendicular to the surface. A similar anisotropy is found in graphite foils, which are impermeable, but also very flexible. Glasslike carbon, which is also impermeable, is, however, completely isotropic. Carbon foams and felts are extremely light and exhibit very good thermal insulation up to high temperatures. In addition to very high strength, carbon fibers have values of Young's modulus greater than that of any other fibers or wires. Carbon fiber/resin composites are therefore more rigid than any other known materials; their specific Young's modulus is five times that of steel.  相似文献   

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A melt can readily solidify to a glass with a three-dimensional or two-dimensional network, or a chain structure, provided that an irregular bonding system can be formed by virtue of free rotation about the bonds between a central atom and the ligands which function as bridging atoms. Such an irregular structure can arise when the system contains a sufficient amount of bridging atoms such as O, F, and S, or bridging groups such as CH2, with bond angles less than 180°. When the network is formed predominantly by trivalent and tetravalent elements, such as As and Ge, the glasses – though they cannot be prepared by cooling of melts – can be obtained by other processes, e.g. by condensing the vaporized substances onto a surface (glasses in the wider sense of the word). As a result of extensive network formation, the bonding systems and, therefore, the short-range order of the atomic arrangement in the melt differ from those in the glass or the crystal. A liquid mixture of substances having unlike molecular size and shape also can form a glass on solidification. Moreover, glasses can be formed even when the systems contains only one component opposing regular packing into a crystal lattice.  相似文献   

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