• Title/Summary/Keyword: Material alteration

검색결과 131건 처리시간 0.023초

무혼잡 무인 운반 차량 시스템의 설계에 관한 연구 (A Study on a Congestion-free Design of AGV System)

  • 박윤선;박대희
    • 대한산업공학회지
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    • 제23권3호
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    • pp.559-580
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    • 1997
  • It is essential to construct on efficient material flow system for the successful introduction of automated manufacturing systems. Automated Guided Vehicle System(AGVS) ploys a significant role more and more in modern manufacturing environments, because of the flexibility and the precision they offer. However, as the size and the complexity of systems increase, the problems of dispatching, routing and scheduling of AGVs became complicated due to their independent and asynchronous demands. In this paper, we review relevant papers, and provide a new and more efficient method for partitioning the AGV system by introducing the concept of Central Path. This method named Central Path design has advantages, since each partitioned workstation group is served by one AGV and the material handling between groups is performed by special AGV that is used for the Central Path. Therefore the congestion problems never occur. Furthermore Central Path Design has a high flexibility for alteration and extension of system. Finally, we demonstrate its efficiency using simulation.

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BAM(Brewster-Angle Microscope)으로 관측한 Langmuir막의 상전이에 관한 연구 (The Study on the Phase Transition of Langmuir Film by Brewster-Angle Microscope)

  • 조완제;송경호;박태곤;박근호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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    • pp.323-326
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    • 2000
  • In this study, we used Brewster-Angle Microscope(BAM) to study on the molecular orientation of monolayer on the water surface. The behaviors of molecules on three different subphase have been observed. Reproducible $\pi$-A isotherm have been obtained only on information about phase transition by molecular area. BAM facilitates the observation of morphology by optical anisotropy and thickness in monolayer and multilayers as BAM is shown to be sensitive to anisotropy of film. Every transition was found by BAM technique, either as a dramatic change in degree of contrast or as a sudden alteration of molecular action and $\pi$-A isotherm.

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Electric-Field Induced Degradation of Ionic Solids

  • Chun, Ja-Kyu;Yoo, Han-Ill
    • 한국세라믹학회지
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    • 제49권1호
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    • pp.48-55
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    • 2012
  • Degradation of performance and life time of a functional material or device thereof is induced, to a great extent, by mass transfer in the material that is driven by various thermodynamic forces imposed intentionally or accidentally during its operation or service. The forces are any gradient of intensive thermodynamic variables, component chemical potentials, electrical potential, temperature, stresses, and the like. This paper reviews electric-field induced degradation phenomena in ionic solid compounds including insulation resistance degradation, crystal shift, microstructural alterations, compositional unmixing, and compound decomposition. Their inner workings are also discussed qualitatively.

e ̄-CF$_4$산란의 전자이동속도 및 특성에너지 연구 (Electron Swarm Drift Velocity and Characteristic Energy in e$^{[-10]}$ -CF$_4$Scattering)

  • 임상원;유회영;김상남;하성철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 추계학술대회 논문집
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    • pp.169-174
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    • 1996
  • In this paper, the electron transport characteristic in CF$_4$has been analysed over the E/N range 1~300(Td) by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The alteration of cross sections from the literature is avoided as much as possible in the analysis. The motion has been calculated to give swarm parameters for the electron drift velocity(W), diffusion coefficient(D$_{L}$), the ratio of the diffusion coefficient to the mobility(D$_{L}$/$\mu$), mean energy($\varepsilon$), the electron energy distribution function. The electron energy distribution function has been analysed in CF$_4$at E/N=50, 100 and 200(Td) for a case of the equilibrium region in the mean electron energy. The results of Boltzmann equation and Monte Carlo simulation have been compared with experimental data by Y. Nakamura and M. Hayashi.shi.

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네마틱 액정의 수면상 단분자막에서의 분자 배향 연구 (A Study on the Molecular Orientation of Nematic Liquid Crystal Monolayers on the water Surface)

  • 조완제;송경호;박근호;강영수;박태곤
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.610-612
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    • 1999
  • In this study, we used both displacement-current method and BAM(Brewster-Angle Microscope) to study on the molecular orientation of monolayer on the water surface. The displacement-current method measured behaviors of molecules by current and BAM was shown to be sensitive to film anisotropy even when the molecules were not tilted as long as the unit cell was anisotropic. Every transition was visible with BAM technique, either as a dramatic change in decree of contrast or as a sudden alteration of the mosaic domain texture.

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Architectural and structural analysis of historical buildings: The case of Kırklareli Museum in Türkiye

  • Ercan Aksoy;Ali Ural
    • Earthquakes and Structures
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    • 제27권3호
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    • pp.239-250
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    • 2024
  • Traditional immovable cultural assets are significant in terms of societal memory and cultural continuity. Therefore, it is essential to preserve their original qualities without alteration while also assessing their resilience under various influences. This study aims to document the Kırklareli Museum building and conduct a performance analysis for potential earthquake scenarios. To this end, surveys of the structure were conducted, on-site inspections were carried out, and ground and material properties were determined for use in the analysis. The 3D model of the structure was prepared to understand its behavior during earthquakes. The analysis results indicate that there will be no damage to the structure. However, it should be noted that damage could occur in the event of a more severe earthquake than the design earthquake specified by the regulations. This study is significant not only for encompassing the museum structure but also for providing a comprehensive evaluation by determining all material properties.

구조지향 Paradigm의 근대건축적 전개에 관한 연구 (A Study on the Evolution of Structure-oriented Paradigm in Modern Architecture)

  • 최아사;윤도근
    • 한국실내디자인학회논문집
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    • 제16호
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    • pp.135-141
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    • 1998
  • The objective of this study is to examine the specific progress in modern architecture with a premise that structure-oriented paradigm, as a primary factor, exerts a strong impacts on 18th and 19th centuries architecture. For this purpose, the concept and meaning backgrounds of structure-oriented paradigm have been checked also intrinsic thought s and critical aspects of modern architecture with the light of structure-oriented paradigm have been studied, This study summarized as follows: 1) The concept of structure-oriented paradigm in accordance with ideologies and technologies is framework of through which is shared as collective consciousness. 2) The backdrops of this consciousness are scientific methodologies stemmed from Renaissance and Enlightenment spiritual absoluteness claimed by German Idealists developed structural engineering with newly introduced material like iron steel and reinforced concrete. 3) The intrinsic through in architectural theories are rational and technological idelolgies which is derived from the backdrops of structure-oriented paradigm. 4)The critical sapects of modern architecture in structure-oriented paradigm point of view are $\circled1$ material alteration and directive imitation of vocabularies in classical architecture with simply using newly introduced building material and structure systems $\circled2$ morphological substitution with abstractly interpreted materials and structure systems $\circled3$ revolutionary conversion into engineering architecture through maximum consideration in compliance with tectonics capabilities

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청색 인광물질을 이용한 유기 발광 다이오드의 효율개선에 관한 연구 (A study on the improvement in the efficiency of blue phosphorescent organic light-emitting diodes)

  • 양미연;김준호;하윤경;김영관
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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    • pp.1070-1073
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    • 2004
  • In this study, Tri(1-phenylpyrazolato)iridium $(Ir(ppz)_3)$ was prepared for the pure blue phosphorescent dopant and various host materials were used for the appropriate energy alignment. Although the luminance was pure blue with the CIE coordinates of x = 0.158, y = 0.139, device efficiencies didn't improve yet. Instead of finding the proper host materials, the alteration of structure of OLEDs affected the improvement of electrical and optical characteristics of the devices. It was worthy that insertion the exciton formation zone with the host material between the emitting zone and the exciton blocking layer. The device with a structure of ITO/NPB/Ir(ppz)3 doped in CBP/CBP for the exciton formation zone/BCP/Liq/Al was fabricated and the characteristics were observed compared with the devices without the exciton formation zone. When CBP was used for the exciton formation zone, the device efficiency reached to over 0.25 cd/A. While the device used CBP only for the host showed the luminous efficiency of under 0.11 cd/A

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1906년 해상보험법상 고지의무의 변경에 관한 연구 (A Study on the Alteration in Duty of Disclosure in the Marine Insurance Act 1906)

  • 김찬영
    • 무역상무연구
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    • 제71권
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    • pp.171-194
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    • 2016
  • In the UK, the legal principle for the duty of disclosure established in Carter v Boehm case was codified in the Marine Insurance Act 1906("MIA"). The duty of disclosure under the MIA is the pre-contractual duty by the insured and therefore, the insured should disclose the every material circumstance that would influence a prudent insurer's judgement. If the insured violates the duty of disclosure, the insurer is entitled to avoid the insurance contract, regardless of whether there was the deliberate or reckless breach, which is unfavorable to the insured. The Law Commission reviewed the duty of disclosure under the MIA in detail and provided the Insurance Act 2015 for the purpose of enhancing the interests of the insured. The Insurance Act 2015("Act"),while the basic legal structure of the duty of disclosure under the MIA still remains, amends it in respect of non-consumer insurance and furthermore, integrate the duty of disclosure and the duty not to misrepresent into the duty of fair presentation of risk. And according to the Act, the insurer is required to more actively communicate with the insured before entering the contract with the result that, if the insured fails to disclose the material circumstance but provides the sufficient information to put the insurer on notice, the insurer should further inquire for the purpose of the insured's revealing the material circumstance. In addition, the Act details the insured's constructive knowledge of material circumstance by reviewing the current case law and introduces a new system for the insurer's proportionate remedy against the insured's breach of the duty of fair presentation of risk.

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Hyperpolarized 129 NMR Study of TiO2 Nanotubes

  • Lee, Sang-Man;Lee, Soon-Chang;Mehrotra, Vandana;Kim, Hae-Jin;Lee, Hee-Cheon
    • Bulletin of the Korean Chemical Society
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    • 제33권2호
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    • pp.511-514
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    • 2012
  • A continuous flow hyperpolarized (HP) $^{129}Xe$ NMR spectroscopy was employed for the first time to investigate $TiO_2$ nanotubes (Ti-NTs) synthesized from commercial nanoparticles with different reaction times. A single peak attributing to channels for Ti-NTs was observed for variable temperature HP $^{129}Xe$ NMR spectra. It was also noted that there is alteration in value for heat of adsorption, ${\Delta}H$ from $12.6{\pm}1.3$ to $16.4{\pm}0.4kJ/mol$ and variation in chemical shift of the xenon adsorbed in channels, ${\delta}_s$ from $120{\pm}2\sim135{\pm}9ppm$ which were closely correlated to channel length and it was shown that P25-24 Ti-NTs with longest channel is most favorite Ti-NTs for Xe adsorption.