• 제목/요약/키워드: quantum mechanics

검색결과 108건 처리시간 0.026초

Energy Transfer Between Diatomic Molecules

  • Kim, Yoo-Hang;Shin, Hyung-Kyu
    • Bulletin of the Korean Chemical Society
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    • 제8권2호
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    • pp.88-96
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    • 1987
  • The effects of initial vibrational energy on VV energy transfer in the collinear collision of two diatomic molecules, either homonuclear or heteronuclear, has been studied over a range of collision energies in classical mechanics. When initial vibrational energy is very large, only a small fraction of vibrational energy in the excited molecule is transferred to the colliding partner. In this case, the VV step is found to be strongly coupled with VT during the collision. At low collision energies, energy transfer in the homonuclear case of $O_2$+ $O_2$ with small initial vibrational energy is found to be very inefficient. In the heteronuclear case of CH + HC with the initial energy equivalent to one vibrational quantum, VV energy exchange is found to be very efficient at such energies. Between 0.3 and 0.5 ev, nearly all of vibrational energy of the excited molecule with one to about three vibrational quanta in CH + HC is efficiently transferred to the colliding partner through pure VV process in a sequence of down steps during the collision. The occurrence of multiple impacts during the collision of two heteronuclear molecules and the collisional bond dissociation of homonuclear molecules are also discussed.

Ab Initio Study of p-tert-Butylcalix[4]crown-6-ether Complexed with Alkyl Ammonium Cations

  • 최종인;장석규;함성욱
    • Bulletin of the Korean Chemical Society
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    • 제22권11호
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    • pp.1248-1254
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    • 2001
  • The conformations and energies of p-tert-butylcalix[4]crown-6-ether (1) and its alkyl ammonium complexes have been calculated by ab initio HF/6-31G quantum mechanics method. The cone conformation was found to be most stable for free host 1. We hav e determined the binding site of these host-guest complexes focusing on the crown-6-ether or p-tert-butylcalix[4]arene pocket of the cone conformation of host molecule 1. The primary binding site of host 1 for the recognition of alkyl ammonium guests was confirmed to be the central part of the crown moiety of cone conformation. The complexation energy calculations revealed that the ammonium cation without alkyl group showed the highest complexation efficiency when combined with host 1, that is in satisfactory agreement with the experimental results.

A GENERALIZED SIMPLE FORMULA FOR EVALUATING RADON-NIKODYM DERIVATIVES OVER PATHS

  • Cho, Dong Hyun
    • 대한수학회지
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    • 제58권3호
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    • pp.609-631
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    • 2021
  • Let C[0, T] denote a generalized analogue of Wiener space, the space of real-valued continuous functions on the interval [0, T]. Define $Z_{\vec{e},n}$ : C[0, T] → ℝn+1 by $$Z_{\vec{e},n}(x)=\(x(0),\;{\int}_0^T\;e_1(t)dx(t),{\cdots},\;{\int}_0^T\;e_n(t)dx(t)\)$$, where e1,…, en are of bounded variations on [0, T]. In this paper we derive a simple evaluation formula for Radon-Nikodym derivatives similar to the conditional expectations of functions on C[0, T] with the conditioning function $Z_{\vec{e},n}$ which has an initial weight and a kind of drift. As applications of the formula, we evaluate the Radon-Nikodym derivatives of various functions on C[0, T] which are of interested in Feynman integration theory and quantum mechanics. This work generalizes and simplifies the existing results, that is, the simple formulas with the conditioning functions related to the partitions of time interval [0, T].

Nystatin Drug as an Effective Corrosion Inhibitor for Mild Steel in Acidic Media- An Experimental and Theoretical Study

  • Mehmeti, Valbone
    • Corrosion Science and Technology
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    • 제21권1호
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    • pp.21-31
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    • 2022
  • Potentiodynamic polarization, EIS measurements, quantum chemical calculations, and molecular dynamic simulations were used to investigate the corrosion behavior of mild steel in 0.5 M aqueous hydrochloric acid medium in the presence or absence of nystatin drug. Potentiodynamic tests suggested that this molecule could act as a mixed inhibitor due to its adsorption on the mild steel surface. The objective of this study was to exploit theoretical calculations to gain a better understanding mechanism of inhibition. Calculating the adsorption behavior of the investigated molecule on Fe (1 1 0) surface was accomplished using Monte Carlo simulation. Molecules were also investigated using Density Functional Theory (DFT), specifically PBE functional, in order to identify the link between molecular structure and corrosion inhibition behavior of the compound under investigation. Adsorption energies between nystatin and iron were estimated more accurately by utilizing Molecular Mechanics calculation with Periodic Boundary Conditions (PBC). Estimated theoretical parameters significantly assisted our understanding of the corrosion inhibition mechanism exhibited by this molecule. They were found to be in accord with experimental results.

QGIS를 이용한 경기도내 토양오염원의 중점관리 지점 선정 (Priority Management Using the QGIS for Sources of Contaminated Soil in Gyeonggi-do Province)

  • 손영금;김지영;박진호;임흥빈;김종수
    • 한국환경보건학회지
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    • 제46권1호
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    • pp.88-95
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    • 2020
  • Object: The purpose of this study was to select priority points for soil management using the location of groundwater and to suggest this method for soil contamination surveys. Method: Groundwater impact range was set to an area of 100 to 500 meters from the center point of agricultural groundwater wells. Data on industrial complex and factory areas, areas of stored or used ores and scrap metals, areas associated with waste and recycling, and traffic-related facilities areas were collected and checked for whether they fall within the groundwater impact range. Longitude and latitude coordinates of these data were mapped on the groundwater impact range using QGIS (Quantum Geographic Information System). Results: Considering the groundwater impact range, the points were selected as follows: 589 points were selected from 6,811 factories and 259 points were selected from 1,511 recycling business points. Traffic-related facility areas were divided between gas stations, bus depots, and auto mechanics. Thirty-four points were selected from 149 bus depots and 573 points were selected from 6,013 auto mechanic points. From the 2,409 gas station points, 323 were selected. Conclusion: Contaminated soil influences groundwater and crops, which can harm human health. However, soil pollution is not easily identified, so it is difficult to determine what has occurred. Pollution must be prevented beforehand and contaminated soil found. By selecting and investigating soil contamination survey points in consideration of the location of groundwater wells, we can safely manage water resources by preventing groundwater contamination in advance.

Cultural Tunneling Effect: Conceptual adoption & Application in movie industry

  • Roh, Seungkook
    • Asia Marketing Journal
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    • 제16권3호
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    • pp.77-100
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    • 2014
  • Many researchers have analyzed the relationship between the financial success patterns of a motion picture and many other factors, such as the production cost, marketing, stars, awards, reviews, genre, and rating. Through these studies, many researchers and investors concluded that big budgets to make a blockbuster movie can serve as an insurance policy to meet their ROI; thus the box office is dominated by blockbuster movies. High-budget blockbuster movies are more likely to receive attention because these movies are more recognizable given their high expenses for production and casting. Therefore, audiences choose blockbusters in an effort to reduce the searching cost and to mitigate the possibility of a regrettable choice. This behavior of consumers, in turn, causes distributors to allocate screens for blockbusters, resulting in "concentration of blockbuster consumption." As such, low-budget films cannot easily become popular due to the lack of distribution. Indeed, low-budget films released on a small number of screens often end up becoming dismal failures. However, there are exceptional examples which are contrary to the general idea in the movie industry that a big budget and showings on a large number of screens can guarantee the success of a movie. Although researchers have attempted to analyze the performances of movies with small budgets, such movies are likely to be regarded as outliers and then be entirely discarded, as they are far from the 'three-sigma' range, especially given that previous research methodologies could not explain the financial success of such unique examples. This study attempts to explain the financial success at the box office of low-budget movies by applying the concept of the tunnel effect in quantum mechanics, as the phenomenon found in the movie industry is similar to a particle's movement in quantum physics. The tunneling effect is a phenomenon by which a particle without enough energy to pass over a potential barrier tunnels through it. Adopting the analogy, this study draws a tunneling probability function and cultural constant to forecast other outliers using the Schrödinger equation. Moreover, the study finds that word-of-mouth creates in the movie industry this phenomenon of finding outliers.

원자모형과 전자배치 단원에 대한 고등학교 학생들의 학습 성취도 및 화학 II 교과서의 설명방식의 차이점에 대한 분석 (Analyses on the Degree of Learning Achievement by Students and on Differences of Explaining in High School Chemistry-II Textbooks for the Atomic Models and Electron Configurations)

  • 김창곤
    • 대한화학회지
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    • 제47권3호
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    • pp.273-282
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    • 2003
  • 본 연구에서는 고등학교 이과계열 학생들 중 화학II의 교과 과목을 선택한 2학년 34명과 3학년 38명의 학생들을 대상으로 "원자 모형과 전자배치"단원의 개념들에 대한 학습 성취도를 알아보기 위하여 설문지를 사용하여 조사하였다. 또한 제 6차 교육과정에 의하여 편찬된 8종의 고등학교 화학 II 교과서에 기술된 이들 개념에 대한 설명 방식을 분석하고 개념설문지 조사 결과와 연계하여 그 개선점에 대하여 논의하였다. 개념설문지의 조사결과 조사대상 학생들의 학습 성취도는 2학년과 3학년 학생들 사이에서 문항별로 부분적인 차이를 보이기는 하지만 전체적으로는 그다지 큰 차이를 보이지 않는 것으로 나타났다. 이러한 결과는 고등학교의 교과과정상 "원자구조와 전자배치" 대한 교과 과정이 2학년 1학기 초반에 다루어지고 있으며 이후에는 이러한 부분과 연계되는 개념들의 보충적인 학습이 지속적으로 이루어지지 않고 있음을 의미하는 것이라 할 수 있다. "원자모형과 전자배치" 단원의 효과적이고 체계적인 학습을 위해서는 기초적인 분광학과 양자역학 개념들에 대한 학습이 필수적으로 선행되어야 하나 현행 고등학교의 교과 구성상 이러한 개념들을 모두 소개하기는 어렵다. 그러므로 교과서의 "참고자료" 등의 부분에 양자역학과 분광학의 기본적인 사항들을 간략하게라도 기술하는 것이 학생들의 이해를 돕는 한가지의 보완 방법이 될 것이라 할 수 있을 것이다. 한편, 본 연구에서 분석한 화학II 교과서들은 전반적으로 유사한 형태 및 설명방식들을 가지고 있는 것으로 나타났다. 그러나 몇 가지의 교과서들에서 Bohr의 원자 모형과 전자구름 모형을 설명하는 과정에서의 연계성이 부족하거나, 전자의 위치에 대한 오개념을 가질 수 있는 여지가 있는 것으로 분석되었다.

과학과 상상력의 중첩성 (The superposition of Science and Imagination)

  • 홍명희
    • 비교문화연구
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    • 제34권
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    • pp.93-114
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    • 2014
  • Gaston Bachelard had a revolutionary progress in the field of human understanding by proposing his theory of image and imagination. His theory of the new image was so powerful, almost all areas of human science, particularly that of literary criticism, were strongly influenced and this influence continues until today. Today almost everyone accepts his theory of the image without much objection, but not rarely asked where began his transfer from the philosophy of science to the images. We propose a hypothesis that the beginning of the new concept of Bachelard's image was inspired by studies of contemporary science, especially quantum mechanics. The Heisenberg's uncertainty principle was the core of quantum mechanics, and opens new perspectives on the material world. We could summarize the message of the uncertainty principle : the material world is made up of various layers, and the material can not be measured by the location and movement at the same time. So we must have a new point of view of another dimension to know this material world. Bachelard had accepted this view of Heisenberg and developed his own theory of epistemological rupture. What is revolutionary in the theory of Bachelard's image is the fact that he looked at the images with the new perspective. The human psyche is another world compared to the rational world that dominates our daily lives. Bachelard insists that the image can not be explained by the concept. The fantasy world is a totally different world to that of rationality. That is why it can not be explained by the language of rationality as the concept. The imaginary world exists independently of the real world, but it is superimposed on the real world. These two worlds are influencing each other, and it is between these two world where our daily lives continues. The declaration of Bachelard 'image is a specific reality' is never a metaphor or rhetorical expression. This is an ontological expression that must truthfully. The imaginary world is a world built on the image and it works according to its own law. It is not a representation or copy of the real world. But the world of imagination are not alone. It exists in the same time and space with the world of science. It is superimposed with the world of science. Both two world influence each other. Bachelard has made a revolutionary change by studying the images. He gave them their own place. It has changed the views on the images that were treated as mere representations of reality. Thanks to him, the image can have its own value, that of a factor that creates reality. Bachelard shows how we can go deep into the source of being and the universe if we look at the pictures with the eyes of other dimensions.

후향적인 인과성은 가능한가? (Is Backwards Causation Possible?)

  • 안건훈
    • 철학연구
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    • 제105권
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    • pp.269-290
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    • 2008
  • 이 논문에서는 '후향적인 인과관계'를 주장하는 견해들을 크게, 자의적인 행위에 근거한 접근방법, 분석수준별 차이에 근거한 접근방법, 물리방정식에 의한 접근방법, 물리현상에 근거한 접근방법으로 나누어 고찰하고, 그 각각의 특징과 문제점들을 지적했다. 이어서 후향적인 인과성을 펼치는 어떠한 견해도 아직은 설득력 있게 받아들여지지 않고 있음을 밝혔다. 후향적인 인과관계를 펼치는 견해들이 인과성분석에서 주류는 아닐지라도, 상호조건적 동시발생적인 측면에 근거해 대칭적인 관계 속에서 인과관계를 파악하거나, 전체상적인 접근에 의거해 서로가 직접 간접으로 인과관계를 유지하는 것으로 파악할 경우는 어느 정도 논거가 선다. 특히 인과그물이나 전체상적인 측면에서 접근할 경우는 더욱 그렇다. 그러나 유용성이라는 측면에서 본다면, 후향적인 인과성고찰은 원인선행설에 비해 그 설득력이 약하다. 이런 점에서 현재로서는 결과가 원인에 앞서지 못한다는 견해가 주류를 이룰 수밖에 없다.

Force Field Parameters for 3-Nitrotyrosine and 6-Nitrotryptophan

  • Myung, Yoo-Chan;Han, Sang-Hwa
    • Bulletin of the Korean Chemical Society
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    • 제31권9호
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    • pp.2581-2587
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    • 2010
  • Nitration of tyrosine and tryptophan residues is common in cells under nitrative stress. However, physiological consequences of protein nitration are not well characterized on a molecular level due to limited availability of the 3D structures of nitrated proteins. Molecular dynamics (MD) simulation can be an alternative tool to probe the structural perturbations induced by nitration. In this study we developed molecular mechanics parameters for 3-nitrotyrosine (NIY) and 6-nitrotryptophan (NIW) that are compatible with the AMBER-99 force field. Partial atomic charges were derived by using a multi-conformational restrained electrostatic potential (RESP) methodology that included the geometry optimized structures of both $\alpha$- and $\beta$-conformers of a capped tripeptide ACE-NIY-NME or ACE-NIW-NME. Force constants for bonds and angles were adopted from the generalized AMBER force field. Torsional force constants for the proper dihedral C-C-N-O and improper dihedral C-O-N-O of the nitro group in NIY were determined by fitting the torsional energy profiles obtained from quantum mechanical (QM) geometry optimization with those from molecular mechanical (MM) energy minimization. Force field parameters obtained for NIY were transferable to NIW so that they reproduced the QM torsional energy profiles of ACE-NIW-NME accurately. Moreover, the QM optimized structures of the tripeptides containing NIY and NIW were almost identical to the corresponding structures obtained from MM energy minimization, attesting the validity of the current parameter set. Molecular dynamics simulations of thioredoxin nitrated at the single tyrosine and tryptophan yielded well-behaved trajectories suggesting that the parameters are suitable for molecular dynamics simulations of a nitrated protein.