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针对当前化学实验翻转课堂教学模式中存在的不足,依托“云班课”,重构了以学生为中心的化学实验“三三三”翻转教学新模式,即将实验教学划分为“三个课堂”:自学课堂、理论课堂和实验课堂等;理论课堂里包含“三个环节”:个人汇报、小组活动和测试点评等;学习效果评判有“三个评价”:自学评价、参与评价和动手评价等。以有机化学实验中“环己烯的合成”为例,采用该新的教学模式开展了教学活动,整个教学过程不仅体现了“以学定教、学生为中心”的教学理念,而且也能发挥出线下传统课堂的优势,实现了将“知识内化”的时间拉长,达到对学生线上自学“知识传授”掌握度的有力检验的目的,更有时间和空间进行课程思政元素的挖掘与融入,完成在知识传播中实现对学生的价值引领。 相似文献
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以学生活动为载体,借助表现性评价,有助于学生学科核心素养的形成。根据“表现性评价”和“证据推理与模型认知”的内涵,从“获取推理证据”“基于证据推理”“建立认知模型” “基于模型认知”等4个维度提出表现性评价量规,以 “空气”第1课时教学内容为例,设计表现性任务。介绍了在“空气”第1课时的教学中,教师在课堂上基于表现性评价观测学生课堂表现,并根据学生素养达成情况及时调整教学,展开“教、学、评”一体化的教学过程。 相似文献
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为培养一批符合社会需求、企业欢迎的“宽基础、多技能、高素质”的复合型技术技能人才,借鉴国内外先进职教经验,以高职石油化工专业群为试点,创建了跨专业复合人才培养体系。通过采取“理实一体化”教学改革,建立现代学徒制试点,推广校企“双主体”协同育人方案,开展跨学院、跨国境交流,打造复合型师资队伍等策略,探索并实践了复合型技术技能人才“跨专业、跨理实、跨校企、跨学院、跨国境”的“五跨”培养模式。 相似文献
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提出了“互联网+”背景下,“无机及分析化学”课程教学“一核心、二目标、三探索、四构建”的教学策略。实施结果表明,基于学生发展的课程核心知识,以“具有解决复杂制药工程、化工工程、材料工程的化学基础知识”“为学习后续课程打下坚实基础”2个具体教学目标为导向,通过开展综合实践活动、案例教学、课程思政等3种教学改革探索,构建线上线下有机衔接的立方书、立体化线上教学资源、线上线下混合型教学模式及过程和结果相融合的SPOC教学模式下的课程评价体系4种教学举措,能有效提高课程教学质量。 相似文献
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“能量”是学生认识化学变化的重要维度,本实验借助手持红外热成像仪“看到”化学反应中的能量变化。在实验中通过拍摄等量的不同酸溶液与氢氧化钠溶液混合反应时的热成像图,从“温度”高低间接反映出热量变化,从宏观的能量变化建立模型,推理微观的成键、断键等过程,探究酸碱中和反应过程的放热以及弱酸电离过程的吸热,并培养学生的证据推理能力和科学探究意识。 相似文献
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燃料电池作为能源转换装置能够高效地将化学能转化为电能,随着技术的发展人们将其作为反应器来完成高附加值的化学品的合成,同时产生一定的电能. 燃料电池反应器因具有反应条件温和、反应过程可控、产物选择性高、能源利用效率高等特点,而被广泛地应用于医药中间体的制备、气体分离、水处理等多个领域. 本文首先按照反应器中阴阳极区域发生反应的类型进行分类,介绍燃料电池反应器在化学品与电能联产中的研究现状和研究进展. 随后描述了燃料电池反应器中存在的问题,并依照催化剂、反应过程等方向对解决方案进行探讨. 最后,对几种新型燃料电池反应器的研究进行了简要的介绍并对其发展做出了展望. 相似文献
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Christopher G. Jesudason 《Journal of mathematical chemistry》2006,39(1):201-230
Chemical and other reaction theories involving thermodynamical equilibrium states utilize statistical mechanical equilibrium
density distributions. Here, a definition of heat-work transformation termed thermo-mechanical coherence is first made, and
it is conjectured that most molecular bonds have the above heat-work transformation property, which models a chemical bond
as a “centrifugal heat engine”, where the internal energy state need not correspond to any of the standard equilibrium densities.
Expressions are derived for the standard Gibbs free energy, enthalpy, and entropy where the bond coordinates need not conform
to a non-degenerate Boltzmann state, since bond breakdown and formation are processes that have direction, whereas equilibrium
distributions are derived when the Hamiltonian is of fixed form, which is not the case for chemical reactions using localized
Hamiltonians. The empirically determined Gibbs free energy from a known molecular dynamics simulation of a dimer reaction
, accords rather well with the theoretical estimate. A relation connecting the rate of reaction with the equilibrium constant
and other kinetic parameters is derived and could place the commonly observed linear relationship between the logarithms of
the rate constant and equilibrium constant on a firmer theoretical footing. These relationships could include analogues of
the Hammett correlations used extensively in physical organic chemistry, as well as others which are temperature dependent.
One prediction of the principles developed here is that the equilibrium standard reaction free energy is more dependent on
the height of the intermolecular potential than its depth, so that the sign of the ΔG
θ can change for varying barrier height with fixed well depth, which may appear counter-intuitive. All the above developments
can be tested directly in simulations and therefore provides a fertile ground for further research with significant implications
on how standard states are determined in relation to the direction of chemical reaction.This work treats the molecular bond
using standard thermodynamics as if it were a system, and it is anticipated that with the advent of single-molecule science
and experiment, that might be one direction in which molecular statistical thermodynamics would develop. 相似文献
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Xiaopeng Wang Jian Gao Zhihua Cheng Dr. Nan Chen Prof. Liangti Qu 《Angewandte Chemie (International ed. in English)》2016,55(47):14643-14647
A new type of responsive battery with the fascinating feature of pressure perceptibility has been developed, which can spontaneously, timely and reliably control the power outputs (e.g., current and voltage) in response to pressure changes. The device design is based on the structure of the Zn–air battery, in which graphene‐coated sponge serves as pressure‐sensitive air cathode that endows the whole system with the capability of self‐controlled energy release. The responsive batteries exhibit superior battery performance with high open‐circuit voltage (1.3 V), and competitive areal capacity of 1.25 mAh cm?2. This work presents an important move towards next‐generation intelligent energy storage devices with energy management function. 相似文献
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论化学学习中的能量观建构 总被引:1,自引:1,他引:0
能量观是中学化学学习中的核心观念。能量观的建构有利于学生形成核外电子运动的能量思维方式,了解从能量的角度研究物质及其转化的思维方法等。能量观建构的基本策略是:(1)在物质的微粒性认识学习中形成物质的微粒具有热能的观念;(2)在原子结构学习中形成核外电子运动的能量思维方式;(3)在元素及其化合物学习中发展高能量的最外层电子不稳定的认识;(4)在化学变化现象的积累学习中强化物质转化伴随有能量变化的认识;(5)通过化学键概念及其理论学习理解物质转化过程中伴随有能量变化;(6)在影响化学反应速率的条件讨论中深化理解有效碰撞理论;(7)在化学热力学问题研究中进一步理解能量守恒;(8)利用概念图技术帮助化学能量观的建构。 相似文献
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Klaus Müller 《Angewandte Chemie (International ed. in English)》1980,19(1):1-13
Theoretical investigation of a chemical reaction requires detailed knowledge of the potential energy of the molecular system. As a first step in such a study, minimum-energy reaction paths have to be mapped on a generally multidimensional molecular potential surface. Even at this stage problems are encountered that have only recently been solved satisfactorily. The difficulties involved and various ways to handle them are discussed in connection with a two-parametric model potential. Three chemical reactions examined illustrate the usefulness of such theoretical investigations as well as their current limitations. 相似文献
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The coming decade will see the rapid emergence of low cost, intelligent, wireless sensors and their widespread deployment throughout our environment. While wearable systems will operate over communications ranges of less than a meter, building management systems will operate with inter-node communications ranges of the order of meters to tens of meters and remote environmental monitoring systems will require communications systems and associated energy systems that will allow reliable operation over kilometers. Autonomous power should allow wireless sensor nodes to operate in a "deploy and forget" mode. The use of rechargeable battery technology is problematic due to battery lifetime issues related to node power budget, battery self-discharge, number of recharge cycles and long-term environmental impact. Duty cycling of wireless sensor nodes with long "SLEEP" times minimises energy usage. A case study of a multi-sensor, wireless, building management system operating using the Zigbee protocol demonstrates that, even with a 1 min cycle time for an 864 ms "ACTIVE" mode, the sensor module is already in SLEEP mode for almost 99% of the time. For a 20-min cycle time, the energy utilisation in SLEEP mode exceeds the ACTIVE mode energy by almost a factor of three and thus dominates the module energy utilisation thereby providing the ultimate limit to the power system lifetime. Energy harvesting techniques can deliver energy densities of 7.5 mW/cm(2) from outdoor solar, 100 microW/cm(2) from indoor lighting, 100 microW/cm(3) from vibrational energy and 60 microW/cm(2) from thermal energy typically found in a building environment. A truly autonomous, "deploy and forget" battery-less system can be achieved by scaling the energy harvesting system to provide all the system energy needs. In the building management case study discussed, for duty cycles of less than 0.07% (i.e. in ACTIVE mode for 0.864 s every 20 min), energy harvester device dimensions of approximately 2 cm on a side would be sufficient to supply the complete wireless sensor node energy. Key research challenges to be addressed to deliver future, remote, wireless, chemo-biosensing systems include the development of low cost, low-power sensors, miniaturised fluidic transport systems, anti-bio-fouling sensor surfaces, sensor calibration, reliable and robust system packaging, as well as associated energy delivery systems and energy budget management. 相似文献
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Guanzhou Lin Husain Almakrami Huzaifa Emran Amar Ruthen Jie Hu Zi Wei Prof. Fuqiang Liu 《Chemphyschem》2021,22(12):1193-1200
Solar energy can be stored via either an indirect route in which electricity is involved as an intermediate step, or a direct route that utilizes photogenerated charge carriers for direct solar energy conversion. In this study, we investigate the fundamental difference between the direct and indirect routes in solar energy conversion using a new photoelectrochemical energy storage cell (PESC) as a model device. This PESC centers on a liquid junction that utilizes CH3NH3PbI3 perovskite to drive photoelectrochemical reactions of Benzoquinone (BQ) and Ferrocene (Fc) redox species. The experimental studies show that the equilibrium redox potentials are 0.1 V and −0.78 V (vs Ag/AgNO3) for Fc+/Fc and BQ/BQ.−, respectively, which would produce a theoretical open-circuit voltage of 0.88 V for the storage device. The physics-based computational analysis shows a relatively flat reaction rate distribution in the electrode for the indirect route; however, in the direct route the photoelectrochemical reaction rate is critically affected by electron concentration due to strong light absorption of the perovskite material, which has been shown to vary by at least 10-fold in the transverse direction across the photoelectrode. The drastic variation of reaction rate in the photoelectrode creates an electric field that is 7.5 times stronger than the bulk electrolyte, which causes the photo-converted reaction product (i. e., BQ.−) to drift away from the photoelectrode thereby creating a constant reaction driving force. As a result, it has been shown that the intrinsic solar to chemical conversion (ISTC) efficiency improves by ∼40 % for the direct route compared to the indirect route at 0.05 mA/cm2. 相似文献
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煤炭能源中的化学问题* 总被引:4,自引:0,他引:4
煤炭是我国的主要能源, 国家可持续发展要求煤的高效洁净燃烧和高效洁净转化。煤炭能源中的主要化学问题就是解决效率、污染、能源形式转化过程中所遇到的化学问题, 包括对煤组成结构的认识、煤中不同组分在热场中的化学变化与相互作用和阶段特征, 特别是煤中污染组分的赋存形态和变迁规律、煤基合成气的催化反应等。 相似文献
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Dr. Martina Cacciarini Anders B. Skov Dr. Martyn Jevric Anne S. Hansen Dr. Jonas Elm Prof. Dr. Henrik G. Kjaergaard Prof. Dr. Kurt V. Mikkelsen Prof. Dr. Mogens Brøndsted Nielsen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7454-7461
One key challenge in the field of exploitation of solar energy is to store the energy and make it available on demand. One possibility is to use photochromic molecules that undergo light‐induced isomerization to metastable isomers. Here we present efforts to develop solar thermal energy storage systems based on the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch. New DHA derivatives with one electron‐withdrawing cyano group at position 1 and one or two phenyl substituents in the five‐membered ring were prepared by using different synthetic routes. In particular, a diastereoselective reductive removal of one cyano group from DHAs incorporating two cyano groups at position 1 turned out to be most effective. Quantum chemical calculations reveal that the structural modifications provide two benefits relative to DHAs with two cyano groups at position 1: 1) The DHA–VHF energy difference is increased (i.e., higher energy capacity of metastable VHF isomer); 2) the Gibbs free energy of activation is increased for the energy‐releasing VHF to DHA back‐reaction. In fact, experimentally, these new derivatives were so reluctant to undergo the back‐reaction at room temperature that they practically behaved as DHA to VHF one‐way switches. Although lifetimes of years are at first attractive, which offers the ultimate control of energy release, for a real device it must of course be possible to trigger the back‐reaction, which calls for further iterations in the future. 相似文献