• Title/Summary/Keyword: LCS

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Synthesis and Characterization of Wholly Aromatic Polyester Liquid Crystalline Thermosets (전방향족 폴리에스터 열경화성 액정의 합성과 특성)

  • Moon, Hyun-Gon;Jung, Myung-Sup;Chang, Jin-Hae
    • Polymer(Korea)
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    • v.36 no.1
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    • pp.9-15
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    • 2012
  • We prepared a series of aromatic liquid crystals (LCs) based on wholly aromatic ester units with the reactive end group methyl maleimide by means of melt condensation method, and the resulting LCs were thermally crosslinked to produce liquid crystalline thermoset (LCT) films. The synthesized LCs and LCTs were characterized with Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), thermomechanical analysis (TMA), and polarizing optical microscopy (POM) with a hot stage. The glass transition temperature ($T_g$) and coefficient of thermal expansion are strongly affected by the mesogen units in their main chain structures. The $p$-substituted biphenyl LC was found to have the highest thermal property value.

The Alignment of Liquid Crystals on the Film Surfaces of Soluble Aromatic Polyimides Bearing t-Butylphenyl and Trimethylsilylphenyl Side Groups

  • Hahm, Suk-Gyu;Jin, Kyeong-Sik;Park, Sam-Dae;Ree, Moon-Hor;Kim, Hyung-Sun;Kwon, Soon-Ki;Kim, Yun-Hi
    • Macromolecular Research
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    • v.17 no.12
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    • pp.976-986
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    • 2009
  • With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.

Simulation Study on the Calculation of Weapon System's Operating Maintenance Costs to develop LCS-P (LCS-P 개발을 위한 무기체계 운용유지비 산출 시뮬레이션 연구)

  • Kim, Kyung-Rok;Kim, Hee-Wook;Jeong, Jun;Cha, Jong-Han;Jeong, Do-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.9
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    • pp.82-91
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    • 2020
  • Recently, the research and development of weapon systems have expanded from ILS centered on acquisition costs to LCS, including operating maintenance costs. Regulations define the provision and formula of operating maintenance costs, but this does not consider the characteristics of the design and operation/maintenance of real weapon systems based on engineering calculations. Therefore, this study suggests a simulation design method to complement these areas and produce more accurate operating maintenance costs. The research procedures are as follows. First, the provision and formula of operating maintenance costs were defined to make the simulation results applicable. Second, a simulation model was developed by reviewing design considerations so that the simulation results reflect reality more accurately. The design considerations include the PBS of weapon systems, operation schedules, specifications for operation/maintenance/warehouse facilities, and basic cost information (personnel expense and spare part/equipment cost). This study is expected to be effective in calculating the operating maintenance costs more easily and accurately.

호처리 용량

  • Im, Ju-Hwan
    • ETRI Journal
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    • v.8 no.2
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    • pp.159-166
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    • 1986
  • 본고는 TDX-1 의 호처리 용량에 관한 것으로 우선 전자교환기에 있어서 일반적인 호처리 용량 측정 방법에 대해 설명하고, LCS(Local Call Simulator)를 이용하여 측정에 의한 결과를 토대로 TDX-1의 호처리 용량을 산출한 결과 135,000BHCA로 추정됨을 밝힌다. RSS의 경우는 시스팀 구성에 따라 7,200~24,000BHCA로 추정된다.

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Interface Mapping and Generation Methods for Intuitive User Interface and Consistency Provision (사용자 인터페이스의 직관적인 인식 및 일관성 부여를 위한 인터페이스 매핑 및 생성 기법)

  • Yoon, Hyo-Seok;Woo, Woon-Tack
    • 한국HCI학회:학술대회논문집
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    • 2009.02a
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    • pp.135-139
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    • 2009
  • In this paper we present INCUI, a user interface based on natural view of physical user interface of target devices and services in pervasive computing environment. We present a concept of Intuitively Natural and Consistent User Interface (INCUI) consisted of an image of physical user interface and a description XML file. Then we elaborate how INCUI template can be used to consistently map user interface components structurally and visually. We describe the process of INCUI mapping and a novel mapping method selection architecture based on domain size, types of source and target INCUI. Especially we developed and applied an extended LCS-based algorithm using prefix/postfix/synonym for similarity calculation.

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Electro-controllable omni-directional laser emissions from a helical polymeric network composite film

  • Jang, Won-Gun;Park, Byoung-Choo;Kim, Min-A;Kim, Sun-Woong;Kim, Yun-Ki;Choi, Eun-Ha;Seo, Yoon-Ho;Cho, Guang-Sup;Kang, Seung-Oun;Takezoe, Hideo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.883-886
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    • 2008
  • In optical information technology, an electro-controllable Photonic Band Gap (PBG) in a photonic crystal (PC) material is potentially useful for the manipulation of light. Despite a great deal of research on PBGs, the reliable use of electro-active PBG material systems is restricted to only a few cases because of the complex and limiting nature of the structures involved. Here, we propose a PBG system that uses a liquid crystal (LC) polymer composite. The composite is made of nematic LCs (NLCs) embedded in polymeric helical networks of photo-polymerized cholesteric LCs (CLCs). The composite film shows a large field-induced reversible color shift over 150 nm of the reflection band, due to the reorientational undulation of the helical axis, similar to the Helfrich effect.

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Cell Gap Dependent Electrode-Optic Characteristics of Fringe-Field Switching Mode using a Liquid Crystal with Negative Dielectric Anisotropy (유전율 이방성의 음인 액정을 이용한 Fringe-Field Switching mode의 cell gap 변화에 따른 전기광학 특성)

  • 정송희;김향율;이종문;이승희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.10
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    • pp.914-922
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    • 2003
  • The FFS (fringe-field switching) mode was known to exhibit both a wide viewing angle and high transmittance, especially when using a liquid crystal with negative dielectric anisotropy. We have studied cell gap-dependent electrode-optic characteristics of the FFS mode using the LC with negative dielectric anisotropy. In case of a small cell gap of 2 ${\mu}$m, the transmittance at the center of pixel and common electrodes is relatively low because effect of surface anchoring that holds the LC to the initial state is larger than that in a large cell gap of 4 .urn such that the LCs in those regions cannot rotate enough. However, in case of a large cell gap of 4 .urn, the effect of surface anchoring becomes relatively small so that the LCs at the center of pixel and common electrode can be twisted enough by applied voltage, giving rise to high transmittance. Therefore, we can conclude that the light efficiency is dependent on the cell gap.

A Decoder Design for High-Speed RS code (RS 코드를 이용한 복호기 설계)

  • 박화세;김은원
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.35T no.1
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    • pp.59-66
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    • 1998
  • In this paper, the high-speed decoder for RS(Reed-Solomon) code, one of the most popular error correcting code, is implemented using VHDL. This RS decoder is designed in transform domain instead of most time domain. Because of the simplicity in structure, transform decoder can be easily realized VLSI chip. Additionally the pipeline architecture, which is similar to a systolic array is applied for all design. Therefore, This transform RS decoder is suitable for high-rate data transfer. After synthesis with FPGA technology, the decoding rate is more 43 Mbytes/s and the area is 1853 LCs(Logic Cells). To compare with other product with pipeline architecture, this result is admirable. Error correcting ability and pipeline performance is certified by computer simulation.

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Analysis of Application using COTS(Commercial Off-The-Shelf) in the U.S. Navy (미 해군의 COTS 적용 사례 분석)

  • Park, Chan-woong;Park, Chan-il;Park, Tae-yong
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.567-569
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    • 2015
  • To response quickly rapidly changing threats, and to reduce development and operational maintenance budget, U.S. Navy has been significantly applied commercial communication equipments instead of MIL-SPEC equipments. Starting from Aegis Baseline 7 combat system, components of systems were replaced to COTS-based system, and Littoral Combat Ships(LCS) and Zumwalt class destroyers have fully COTS-based combat system. In this paper, it is surveyed and analyzed that cases of COTS-based systems were applied and is compared difference from each type of ships.

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