共查询到20条相似文献,搜索用时 109 毫秒
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化学进展与化学教育的前景 总被引:6,自引:0,他引:6
化学进展与化学教育的前景王夔(北京医科大学药学院100083)现在的化学教育要解决两个重要的、带有方向性的问题。一个是在科学技术迅猛发展以及人类进步向科学技术不断提出新问题、新需求之际,化学科学怎样安排它的今天和明天?化学教育怎样适应这一特点?第二个... 相似文献
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化学知识是环境化学知识的基础。化学概念和理论能够对大气环境中的化学反应、土壤环境中的化学反应、水体环境中的化学反应以及水体中存在的平衡等内容进行分析和解释。环境化学知识是运用化学知识研究物质的环境化学行为以及治理化学污染物质而形成的知识体系。对环境化学问题的深入研究能够促进化学的发展。 相似文献
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在我国核能快速发展的新形势下,新型核能资源的开发、乏燃料后处理、放射性废物处理与处置等核燃料循环化学研究日益活跃。随着科学技术的不断发展,离子加速器、反应堆、各种类型的探测器和分析设备、以及计算机技术等的发展,核化学与放射化学研究的范围和成果在不断扩展和增加,如核安全、环境放射化学、放射分析化学、放射性药物与标记化合物等,研究成果对于国防建设、核能发展、核技术应用等方面具有重要支撑作用。本文综述了近年来国内在上述领域所取得的研究进展。共引用参考文献161篇。 相似文献
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绿色化学与绿色化学教育 总被引:124,自引:10,他引:114
本文介绍了绿色化学的定义和内涵,绿色化学的 12条原则,“原子经济”概念,绿色化学的研究动态以及实施绿色化学教育的意义和方法。 相似文献
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绿色化学是从根本上消除环境污染的必由之路。由于某些传统农药是引起环境污染的一个重要因素,因而对农药化学中的绿色化学进行研究和推广具有非常重要的意义。本文应用绿色化学原理,对农药化学中的一些绿色化学方法和技术作了简单介绍。 相似文献
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Liu K 《The Journal of chemical physics》2006,125(13):132307
A critical overview of the recent progress in crossed-beam reactive scattering is presented. This review is not intended to be an exhaustive nor a comprehensive one, but rather a critical assessment of what we have been learning about bimolecular reaction dynamics using crossed molecular beams since year 2000. Particular emphasis is placed on the information content encoded in the product angular distribution-the trait of a typical molecular beam scattering experiment-and how the information can help in answering fundamental questions about chemical reactivity. We will start with simple reactions by highlighting a few benchmark three-atom reactions, and then move on progressively to the more complex chemical systems and with more sophisticated types of measurements. Understanding what cause the experimental observations is more than computationally simulating the results. The give and take between experiment and theory in unraveling the physical picture of the underlying dynamics is illustrated throughout this review. 相似文献
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Henriksen NE 《Chemical Society reviews》2002,31(1):37-42
Chemical reactions are at the heart of chemistry and the dream of controlling the outcome of these reactions is an old one. Thus, with given reactants, a solvent and perhaps assisted by a catalyst, we would like to 'steer' the reactants into a particular desired product. This review focuses on how to control the dynamics of chemical reactions, beyond traditional temperature control, with the emphasis on unimolecular reactions. The electromagnetic radiation of lasers can induce so-called coherent dynamics. The recent theoretical and experimental results on this coherent control are explained and illustrated with computational and experimental examples. 相似文献
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Verlet JR 《Chemical Society reviews》2008,37(3):505-517
Ultrafast spectroscopy allows chemical and physical processes to be observed on time-scales faster than the nuclear motion within molecules. This tutorial review explores how such experiments, and specifically time-resolved photoelectron spectroscopy on gas-phase cluster anions, provide a molecular-level understanding of the processes that are normally associated with condensed-phase dynamics. 相似文献
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S. Handrock-Meyer L.V. Kalachev K.R. Schneider 《Journal of mathematical chemistry》2001,30(2):133-160
Modeling reaction kinetics in a homogeneous medium usually leads to stiff systems of ordinary differential equations the dimension of which can be large. The problem of determination of the minimal number of phase variables needed to describe the characteristic behavior of large scale systems is extensively addressed in current chemical kinetics literature from different point of views. Only for a few of these approaches there exists a mathematical justification. In this paper we describe and justify a procedure allowing to determine directly how many and which state variables are essential in a neighborhood of a given point of the extended phase space. This method exploits the wide range of characteristic time-scales in a chemical system and its mathematical justification is based on the theory of invariant manifolds. The procedure helps to get chemical insight into the intrinsic dynamics of a complex chemical process. 相似文献
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Chemical theory and its application to dynamical electrons in molecules under intense electromagnetic fields is explored, in which we take an explicit account of nuclear nonadiabatic (kinematic) interactions along with simultaneous coupling with intense optical interactions. All the electronic wavefunctions studied here are necessarily time-dependent, and thereby beyond stationary state quantum chemistry based on the Born-Oppenheimer framework. As a general and tractable alternative framework with which to track the electronic and nuclear simultaneous dynamics, we propose an on-the-fly method to calculate the electron and nuclear wavepackets coupled along the branching non-Born-Oppenheimer paths, through which their bifurcations, strong quantum entanglement between nuclear electronic motions, and coherence and decoherence among the phases associated with them are properly represented. Some illustrative numerical examples are also reported, which are aimed at our final goals; real time tracking of nonadiabatic electronic states, chemical dynamics in densely degenerate electronic states coupled with nuclear motions and manipulation and/or creation of new electronic states in terms of intense lasers, and so on. Other examples are also presented as to how the electron wavepacket dynamics can be used to analyze chemical reactions, shedding a new light on some typical and conventional chemical reactions such as proton transfer followed by tautomerization. 相似文献
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Prof. Dr. Katharine Moore Tibbetts 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8431-8439
The ultrafast dynamics of polyatomic radical cations contribute to important processes including energy transfer in photovoltaics, electron transfer in photocatalysis, radiation-induced DNA damage, and chemical reactions in the upper atmosphere and space. Probing these dynamics in the gas phase is challenging due to the rapid dissociation of polyatomic radical cations following electron removal, which arises from excess electronic excitation of the molecule during the ionization process. This Concept article introduces the reader to how the pump-probe technique of femtosecond time-resolved mass spectrometry (FTRMS) can overcome this challenge to capture coherent vibrational dynamics on the femtosecond timescale in polyatomic radical cations and enable the analysis of their dissociation pathways. Examples of FTRMS applied to three families of polyatomic radical cations are discussed. 相似文献
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The dynamic self-assembly mechanism of fullerene molecules is an irreversible process emerging naturally under the nonequilibrium conditions of hot carbon vapor and is a consequence of the interplay between the dynamics and chemistry of polyyne chains, pi-conjugation and corresponding stabilization, and the dynamics of hot giant fullerene cages. In this feature article we briefly present an overview of experimental findings and past attempts to explain fullerene formation and show in detail how our recent quantum chemical molecular dynamics simulations of the dynamics of carbon vapor far from thermodynamic equilibrium have assisted in the discovery of the combined size-up/size-down "shrinking hot giant" road that leads to the formation of buckminsterfullerene C60, C70, and larger fullerenes. This formation mechanism is the first reported case of order created out of chaos where a distinct covalent bond network of an entire molecule is spontaneously self-assembled to a highly symmetric structure and fully explains the fullerene formation process consistently with all available experimental observations a priori. Experimental evidence suggests that it applies universally to all fullerene formation processes irrespective of the carbon source. 相似文献