• 제목/요약/키워드: Structure

검색결과 90,036건 처리시간 0.071초

Coverage Dependent Adsorption and Electronic Structure of Threonine on Ge (100) Surface

  • 이명진;김기정;이한길
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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    • pp.212-212
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    • 2012
  • The Coverage dependent attachment of multifunctional groups included in threonine molecules adsorbed to Ge (100)$-2{\times}1$ surface was investigated using core-level photoemission spectroscopy (CLPES) and density functional theory (DFT) calculations. The core-level spectra at a low coverage indicated that the both carboxyl and amine groups participated in the bonding with the Ge (100) surface by "O-H dissociated and N-dative bonded structure". However, at high coverage level, additional adsorption geometry of "O-H dissociation bonded structure" appeared possibly to minimize the steric hindrance between adsorbed molecules. Moreover, the C 1s, N 1s, and O 1s core level spectra confirmed that the carboxyl oxygen is more competitive against the hydroxymethyl oxygen in the adsorption reaction. The adsorption energies calculated using DFT methods suggested that four of six adsorption structures were plausible. These structures were the "O-H dissociated-N dative bonded structure", the "O-H dissociation bonded structure", the "Om-H dissociated-N dative bonded structure", and the "Om-H dissociation bonded structure" (where Om indicates the hydroxymethyl oxygen). These structures are equally likely, according to the adsorption energies alone. Conclusively, we investigate in threonine on Ge (100) surface system that the "O-H dissociated-N dative bonded structure" and the "O-H dissociation bonded structure" are preferred at low coverage and high coverage.

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On determining seismic anchor force of anchoring frame structure supporting three-stage slope

  • Lin, Yu-liang;Lu, Li;Li, Ying-xin;Xue, Yuan;Feng, Zhi-jun;Wang, Zhi-meng;Yang, Guo-lin
    • Geomechanics and Engineering
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    • 제22권3호
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    • pp.265-275
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    • 2020
  • As a flexible supporting structure, the anchoring frame structure is widely adopted to support multistage slopes in high earthquake-intensity area for its effectiveness and practicality. The previous study indicates that the anchor of anchoring frame structure is the most likely to be damaged during earthquakes. It is crucial to determine the pull-out capacity of anchor against seismic force for the seismic design of anchoring frame structure. In this study, an analytical model of a three-stage slope supported by anchoring frame structure is established, and the upper bound method of limit analysis is applied to deduce the seismic anchor force of anchoring frame structure. The pull-out capacity of anchor against seismic force of anchoring frame structure at each stage is obtained by computer programming. The proposed method is proved to be reasonable and effective compared with the existing published solution. Besides, the influence of main parameters on the pull-out capacity of anchor against seismic force is analyzed to provide some recommendations for the seismic design of anchoring frame structure.

간호학생의 분만관찰경험 (The Observational Experience of Labor and Delivery by Student Nurses in the Clinical Setting)

  • 고명숙
    • 대한간호학회지
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    • 제27권4호
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    • pp.892-900
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    • 1997
  • The purpose of this study was to use phenomenological perspectives to identify the meaning and structure of the observational experience of labor and delivery by student nurses in the clinical setting. The participants were 115 junior and senior students from Christian College of Nursing in Kwang Ju. The students were asked to write about their observational experience in the delivery room. Colaizzi's method was used for phenomenological analysis. The investigator analysed the data to identify and categorize themes and basic structural elements. Twelve themes and eight basic structure were identified. The process of the observational experience in labor and delivery has three proposed phases : anticipatory, observational and post-observational. In the anticipatory phase, nursing students were related only to the event of anticipated labor and delivery of clients. Structure 1, feeling of expectation and fear, was identified. In the observational phase, students were related to the labor and delivery situation, a woman delivered and a newborn. Structure 2, shock and suffering, was identified in relation to the labor and delivery situation. Structure 3, need for caring and satisfaction, was identified in relation to the woman delivered. Structure 4, feeling of mystery and joy, was identified in relation to the newborn. In the post-observational phase, relations between students and the life of a human being, students and self in the future, students and their mothers and students and women and God appeared. And in these relations 〈structure 5, valuable〉, 〈structure 6, feeling of expectation and fear〉, 〈structure 7, love and appreciation〉 and 〈structure 8, greatness〉 were identified.

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다중지점 지진하중을 받는 돔 구조물의 지진응답 제어 (Seismic Response Control of Dome Structure Subjected to Multi-Support Earthquake Excitation)

  • 김기철;강주원
    • 한국공간구조학회논문집
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    • 제14권4호
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    • pp.89-96
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    • 2014
  • Spatial structures as like dome structure have the different dynamic characteristics from general rahmen structures. Therefore, it is necessary to accurately analyze dynamic characteristics and effectively control of seismic response of spatial structure subjected to multi-supported excitation. In this study, star dome structure that is subjected to multi-supported excitation was used as an example spatial structure. The response of the star dome structure under multiple support excitation are analyzed by means of the pseudo excitation method. Pseudo excitation method shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. And the application of passive tuned mass damper(TMD) to seismic response control of star dome structures has been investigated. From this numerical analysis, it is shown that the seismic response of spatial structure under multiple support seismic excitation are different from those of spatial structure under unique excitation. And it is reasonable to install TMD to the dominant points of each mode. And it is found that the passive TMD could effectively reduce the seismic responses of dome structure subjected to multi-supported excitation.

순환대칭으로 다중연결된 구조물의 유한요소 진동해석 (Finite Element Vibration Analysis of Multiply Interconnected Structure with Cyclic Symmetry)

  • 김창부;안종섭;심수섭
    • 소음진동
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    • 제7권4호
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    • pp.637-644
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    • 1997
  • In this paper, a method of finite element analysis is presented for efficient calculation of vibration characteristics of not only simply interconnected structure with cyclic symmetry but also multiply interconnected structure with cyclic symmetry by using discrete Fourier trandform by means of a computer with small memory in a short time. Simply interconnected structure means it is composed of substructures which are adjacent themselves in circumferential direction. First, a mathematical model of multiply interconnected structure with cyclic symmetry is defined. The multiply interconnected structure is partitioned into substructures with the same goemetric configuration and constraint eqauations to be satisfied on connecting boundaries are defined. Nodal displacements and forces are transformed into complex forms through discrete Fourier transform and then finite element analysis is performed for just only a representative substructure. In free vibration analysis, natural frequencies of a whole structure can be obtained through a series of calculation for a substructure along the number of nodal diameter. And in forced vibration analysis, forced response of whole structure can be achieved by using inverse discrete Fourier transform of results which come from analysis for a substructure.

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웹 문서로부터 논리적 구조 추출 (Extracting Logical Structure from Web Documents)

  • 이민형;이경호
    • 한국멀티미디어학회논문지
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    • 제7권10호
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    • pp.1354-1369
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    • 2004
  • 본 논문에서는 웹 문서를 XML 문서로 변환하기 위한 논리적 구조분석 방법을 제안한다. 제안된 방법은 비주얼 그룹화, 요소 식별, 그리고 논리적 그룹화의 세 단계로 구성된다. 특히 정교한 수준의 논리적 구조분석을 지원하기 위하여 특정 주제에 속하는 문서 유형의 논리적 계층 구조를 효과적으로 기술할 수 있는 문서 모델을 정의한다. 제안된 방법은 비주얼 그룹화를 통해서 추출된 시각적 계층구조와 문서 유형에 대한 논리적 구조 정보를 기술한 문서 모델에 기반하기 때문에 보다 정교한 수준의 구조 분석을 지원한다. 제안된 방법의 성능을 평가하기 위하여 웹으로부터 추출한 다수의 HTML 문서를 대상으로 실험한 결과, 기존 연구와 비교하여 논리적 구조분석을 성공적으로 수행하였다. 제안된 방법은 논리적 구조분석의 최종 결과로서 XML문서를 생성하기 때문에 문서의 재 사용성을 높인다.

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Seismic fragility assessment of isolated structures by using stochastic response database

  • Eem, Seung-Hyun;Jung, Hyung-Jo
    • Earthquakes and Structures
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    • 제14권5호
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    • pp.389-398
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    • 2018
  • The seismic isolation system makes a structure isolated from ground motions to protect the structure from seismic events. Seismic isolation techniques have been implemented in full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. As for the responses of an isolated structure due to seismic events, it is well known that the most uncertain aspects are the seismic loading itself and structural properties. Due to the randomness of earthquakes and uncertainty of structures, seismic response distributions of an isolated structure are needed when evaluating the seismic fragility assessment (or probabilistic seismic safety assessment) of an isolated structure. Seismic response time histories are useful and often essential elements in its design or evaluation stage. Thus, a large number of non-linear dynamic analyses should be performed to evaluate the seismic performance of an isolated structure. However, it is a monumental task to gather the design or evaluation information of the isolated structure from too many seismic analyses, which is impractical. In this paper, a new methodology that can evaluate the seismic fragility assessment of an isolated structure is proposed by using stochastic response database, which is a device that can estimate the seismic response distributions of an isolated structure without any seismic response analyses. The seismic fragility assessment of the isolated nuclear power plant is performed using the proposed methodology. The proposed methodology is able to evaluate the seismic performance of isolated structures effectively and reduce the computational efforts tremendously.

Impact of Capital Structure on Profitability: A Comparative Study of Islamic and Conventional Banks of Pakistan

  • QAYYUM, Noor ul;NOREEN, Umara
    • The Journal of Asian Finance, Economics and Business
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    • 제6권4호
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    • pp.65-74
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    • 2019
  • This study has two main purposes; first, it examines the effect of capital structure on profitability of Islamic and conventional banks; second, it determines that whether the capital structure of Islamic and conventional banks is same or not. A sample of ten banks was taken over the period 2006-2016. Independent samples T-test was used for finding the comparison between the capital structure of Islamic and conventional banks while for assessing the impact of capital structure on profitability, regression analysis (Fixed effects model) was used. Results showed that the capital structure of both types of banks was similar except for bank size which differed significantly. Moreover, ROA was negatively correlated to the capital structure of both conventional and Islamic banks. In contrast, ROE was positively correlated to the capital structure of both conventional and Islamic banks. In addition to that, two explanatory variables were positively correlated while two were negatively correlated to EPS for both Islamic and conventional banks. This study proves the existence of prominent theories of capital structure (pecking order theory and trade-off theory) for both conventional and Islamic banks in Pakistan and also validates the economies of scale.

안팍구조(構造)-한국건축공간(韓國建築空間)의 구조주의적(構造主義的) 해석(解析) (The In/Out Structure : Interpretation of the Korean Architectural Space by Structuralism)

  • 이희봉
    • 건축역사연구
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    • 제1권2호
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    • pp.172-182
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    • 1992
  • The binary classification, Yin & Yang, can be shown in our culture. Yin & Yang thinking reveals the Up/Down (Principal/Subordinate) relation in space, and Before/After relation in time, and it shows the sequence of Contrast${\to}$Reconciliation & Unification${\to}$Contrast. For example, a follower is Yin against King, while Yang as a father against his son in our trational cognitive structure. With Left/Right, Front/Rear, and Upper/Lower, In/Out division is a basic body-space term to grasp the space position. In the traditional Korean house, when we go out from the deepest 'In', Anbang to Daechung, we may call Anbang 'In' and Daechung 'Out'. When from Daechung to Anmadang reversely, we call Daechung 'In' and Anmadang 'Out'. Namely, Daechung is both 'In' and 'Out'. This is a fallacy logic in view of western basic conception. 'The In/Out Structure, system of a series of inner spaces, is defined as a transformation of cognitive structure of Yin & Yang thinking to the Korean architectural space. The space structure is one of the important deep structure in Korean society.' The concept of the space structure, apperred in east Asia, can make humane space, for it is not a physical 'type' of typepology but related to cognitive structure of human thinking, The structure is applicable to space design in modern society, for the cognitive structure exists in living culture by transformation.

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진동대실험을 통한 축소 아치구조물의 고유진동주기 분석 (Natural Vibration Period of Small-scaled Arch Structure by Shaking Table Test)

  • 김기철;강주원
    • 한국공간구조학회논문집
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    • 제15권4호
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    • pp.107-114
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    • 2015
  • Large spatial structures can not easily predict the dynamic behavior due to the lack of construction and design practices. The spatial structures are generally analyzed through the numerical simulation and experimental test in order to investigate the seismic response of large spatial structures. In the case of analysis for seismic response of large spatial structure, the many studies by the numerical analysis was carried out, researches by the shaking table test are very rare. In this study, a shaking table test of a small-scale arch structure was conducted and the dynamic characteristics of arch structure are analyzed. And the dynamic characteristics of arch structures are investigated according to the various column cross-section and length. It is found that the natural vibration periods of the small-scaled arch structure that have large column stiffness are very similar to the natural vibration period of the non-column arch structure. And in case of arch structure with large column stiffness, primary natural frequency period by numerical analysis is very similar to the primary natural frequency period of by shaking table test. These are because the dynamic characteristics of the roof structure are affected by the column stiffness of the spatial structure.