• 제목/요약/키워드: degree of alignment

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광배향기술을 이용한 액정배향의 기구 및 폴리이미드의 분자구조가 프리틸트각에 미치는 영향 (Liquid Crystal Alignment and Generation of Pretilt Angle by Using Photo-alignment Techniques on Different Polymer Molecules)

  • 서대식;황율연;이창훈
    • 한국전기전자재료학회논문지
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    • 제11권6호
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    • pp.477-480
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    • 1998
  • In this paper, we investigated the liquid crystal(LC) alignment and generation of pretilt angle by using photo-alignment techniques on two kinds of polyimide(PI) surface, It was found that the uniform alignment for nematic(N) LC is obtained in a cell with slanted UV light irradiation on PI surface without side chain. We successfully observed that the pretilt angle of NLC is generated about $3^{\circ}$ with an incident angle of 70 degree on the PI surface without side chain. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecules and the polymer surfaces.

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A Model-Based Method for Information Alignment: A Case Study on Educational Standards

  • Choi, Namyoun;Song, Il-Yeol;Zhu, Yongjun
    • Journal of Computing Science and Engineering
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    • 제10권3호
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    • pp.85-94
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    • 2016
  • We propose a model-based method for information alignment using educational standards as a case study. Discrepancies and inconsistencies in educational standards across different states/cities hinder the retrieval and sharing of educational resources. Unlike existing educational standards alignment systems that only give binary judgments (either "aligned" or "not-aligned"), our proposed system classifies each pair of educational standard statements in one of seven levels of alignments: Strongly Fully-aligned, Weakly Fully-aligned, Partially-$aligned^{***}$, Partially-$aligned^{**}$, Partially-$aligned^*$, Poorly-aligned, and Not-aligned. Such a 7-level categorization extends the notion of binary alignment and provides a finer-grained system for comparing educational standards that can broaden categories of resource discovery and retrieval. This study continues our previous use of mathematics education as a domain, because of its generally unambiguous concepts. We adopt a materialization pattern (MP) model developed in our earlier work to represent each standard statement as a verb-phrase graph and a noun-phrase graph; we align a pair of statements using graph matching based on Bloom's Taxonomy, WordNet, and taxonomy of mathematics concepts. Our experiments on data sets of mathematics educational standards show that our proposed system can provide alignment results with a high degree of agreement with domain expert's judgments.

Effects of Thermal Imidization and Annealing on Liquid Crystal Alignment ever Rubbed Polyimide Layers: Change in the Pretilt Angle

  • Paek, Sang-Hyon
    • Macromolecular Research
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    • 제9권6호
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    • pp.303-312
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    • 2001
  • The fabrication of liquid crystal display (LCD) panels involves several thermal processes such as imidization of the alignment layer (AL) and annealing of the rubbed polyimide AL. The nature of these processes on the LC alignment, especially on the pretilt angle (Θ$\_$p/) has been systematically studied, employing various types of polyimide structures. The imidization effect depends on the nature of polyimid precursors; Θ$\^$p/ increases with the degree of the imidization for the main-chain type of ALs, due to the decrease in the surface polarity, but this relation is not applicable to the alkylated ones in which the steric effect at the AL surface by the aliphatic side chains is dominant. Annealing of the rubbed polyimide AL deteriorates its rubbing-induced molecular orientation and subsequently the overlying LC alignment, resulting in the decrease in Θ$\_$p/. Especially, annealing of the LC cell affects the LC-AL interaction as well as the AL orientation and thus its effect on LC alignment depends sensitively on the nature of LC-polyimide interface; aromatic moiety in the polyimide structure gives better thermal stability of LC alignment while fluorinated polyimide ALs induce the less stable alignment.

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The Spin-Orbit Alignment of Dark Matter Halo Pairs: Dependence on the Halo Mass and Environment

  • An, Sung-Ho;Yoon, Suk-Jin
    • 천문학회보
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    • 제44권1호
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    • pp.35.1-35.1
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    • 2019
  • We present a statistical analysis on the spin-orbit alignment of dark matter halo pairs in cosmological simulations. The alignment is defined as the angular concurrence between the halo spin vector (${\vec{S}}$) and the orbital angular momentum vector (${\vec{L}}$) of the major companion. We identify interacting halo pairs with the mass ratios from 1:1 to 1:3, with the halo masses of 10.8 < $Log(M_{halo}/M_{sun}$) < 13.0, and with the separations smaller than a sum of their virial radii ($R_{12}<R_{1,vir}+R_{2,vir}$). Based on the total energy ($E_{12}$), the pairs are classified into flybys ($E_{12}$ > 0) and mergers ($E_{12}{\leq}0$). By measuring the angle (${\theta}_{SL}$) between ${\vec{S}}$ and ${\vec{L}}$, we confirm a strong spin-orbit alignment signal such that the halo spin is preferentially aligned with the orbital angular momentum of the major companion. We find that the signal of the spin-orbit alignment for the flyby is weaker than that for the merger. We also find an unexpected excess signal of the spin-orbit alignment at $cos{\theta}_{SL}{\sim}0.25$. Both the strength of the spin-orbit alignment and the degree of the excess depend only on the environment. We conclude that the halo spin is determined by the accretion in a preferred direction set by the ambient environment.

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각막형상과 난시도에 따른 구면 RGP 렌즈와 비구면 RGP 렌즈의 플루레신 염색 패턴 비교 (The Comparison of Fluorescein Patterns between Spherical RGP Lens and Aspherical RGP Lens by Corneal Type and Astigmatic Degree)

  • 박은혜;김소라;박미정
    • 한국안광학회지
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    • 제17권1호
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    • pp.37-45
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    • 2012
  • 목적: 구면 RGP 렌즈 및 비구면 RGP 렌즈를 양호하게 피팅할 때 중심부와 주변부의 플루레신 염색 면적이 난시도 및 각막형상에 따라 어떻게 달라지는 지를 비교하여 렌즈와 각막과의 정렬상태가 렌즈의 디자인에 따라 어떠한 차이가 있는지를 알아보고자 하였다. 방법: 직난시를 가진 19~30세($25.12{\pm}3.52$세)의 90안을 대상으로 구면 및 비구면 RGP 렌즈를 착용시키고 플루레신 염색 패턴을 분석하였으며, 이의 정량적인 평가를 위하여 중심부와 주변부의 면적을 계산하여 비교하였다. 결과: 양호한 피팅이 되는 렌즈의 베이스커브가 구면 RGP 렌즈와 비구면 RGP 렌즈가 동일한 경우는 72%에 달하였으나, 대칭나비형 각막과 높은 난시도를 가진 경우에는 동일한 베이스커브에서 구면 RGP 렌즈와 비구면 RGP 렌즈가 양호한 피팅이 될 가능성이 적어졌다. 양호하게 피팅된 비구면 RGP 렌즈의 주변부 플루레신 염색 면적은 구면 RGP 렌즈보다 더 작았으며, 두 디자인의 렌즈 모두 난시가 심해질수록 주변부 면적은 감소하였고 원형 각막보다도 대칭 나비형 각막에서의 주변부 면적이 더 작았다. 동일한 난시도의 각막에서는 두 각막 형상 모두에서 양호하게 피팅된 비구면 RGP 렌즈의 주변부 플루레신 염색 면적이 더 작았다. 결론: 본 연구를 통하여 RGP 렌즈의 각막과의 정렬상태의 달라지는 정도가 렌즈 디자인, 각막의 난시도, 각막 형상에 의해 차이가 있음을 알 수 있었다. 따라서 렌즈 디자인과 각막의 정렬상태의 정량적인 고찰을 통한 본 연구결과는 RGP 렌즈의 피팅 가이드라인 설정, 적합한 디자인 개발, 부분별 누액양에 대한 기초자료로 사용될 수 있을 것이다.

단일벽 탄소나노튜브의 수평배향도 및 밀도 향상 합성 (Synthesis of Single-Walled Carbon Nanotubes for Enhancement of Horizontal-Alignment and Density)

  • 곽은혜;임호빈;정구환
    • 한국표면공학회지
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    • 제47권6호
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    • pp.347-353
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    • 2014
  • We present a synthesis of single-walled carbon nanotubes(SWNTs) for enhancement of parallel-alignment and density using chemical vapor deposition with methane feed gas. As-purchased ST-cut quartz substrates were heat-treated and line-patterned by electron-beam lithography in order to grow SWNTs with parallel alignment. We investigated the effects of various synthesis parameters such as catalyst oxidation, reduction, and synthesis conditions in order to enhance both tube density and degree of parallel alignment. The condition of $1{\AA}$ of Fe catalyst film, atmospheric oxidation at $750^{\circ}C$ for 10 min, reduction under 400 Torr for 5 min, and growth at $865^{\circ}C$ under 300 Torr yields $33tubes/10{\mu}m$, which is the highest tube density with parallel alignment. Based on the results of atomic force microscope and Raman spectroscopy, it was found that SWNTs have diameter range of 0.8-2.0 nm. We believe that the present work would contribute to the development of SWNTs-based flexible functional devices.

대면적/고정밀 3차원 표면형상의 5자유도 정합법 개발 및 평가 (Development and Evaluation of Stitching Algorithm With five Degrees of Freedom for Three-dimensional High-precision Texture of Large Surface)

  • 이동혁;안정화;조남규
    • 한국생산제조학회지
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    • 제23권2호
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    • pp.118-126
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    • 2014
  • In this paper, a new method is proposed for the five-degree-of-freedom precision alignment and stitching of three-dimensional surface-profile data sets. The control parameters for correcting thealignment error are calculated from the surface profile data for overlapped areas among the adjacent measuring areas by using the "least squares method" and "maximum lag position of cross correlation function." To ensure the alignment and stitching reliability, the relationships betweenthe alignment uncertainty, overlapped area, and signal-to-noise level of the measured profile data are investigated. Based on the results of this uncertainty analysis, an appropriate size is proposed for the overlapped area according to the specimen's surface texture and noise level.

접촉식 리소그라피의 정렬공정을 위한 압전구동 초정밀 스테이지 (A Piezo-driven Ultra-precision Stage for Alignment Process of a Contact-type Lithography)

  • 최기봉;이재종;김기홍;임형준
    • 한국생산제조학회지
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    • 제20권6호
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    • pp.756-760
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    • 2011
  • This paper proposed an alignment stage driven by piezo actuators for alignment process of a contact-type lithography. Among contact-type lithography processes, an UV-curable nanoimprint process is an unique process to be able to align patterns on upper and lower layers. An alignment stage of the UV-curable nanoimprint process requires nano-level resolution as well as high stiffness to overcome friction force due to contact moving. In this paper, the alignment stage consists of a compliant mechanism using flexure hinges, piezo actuators for high force generation, and capacitive sensors for high-resolution measurement. The compliant mechanism is implemented by four prismatic-prismatic compliant chains for two degree-of-freedom translations. The compliant mechanism is composed of flexure hinges with high stiffness, and it is directly actuated by the piezo actuators which increases the stiffness of the mechanism, also. The performance of the ultra-precision stage is demonstrated by experiments.

다채널 광정렬 장치에서의 다자유도 회전 스테이지 동작 특성에 관한 연구 (A Study on the Mechanism of Rotational Stage with Multi Degree of Freedom for Multi-Channel Optical Alignment System)

  • 정상화;차경래;최석봉;김광호;박준호;이경형
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 춘계학술대회 논문집
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    • pp.219-224
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    • 2004
  • In recent years, as the demands of VBNS(Very high speed Backbone Network Service) and VDSL(Very high-data rate Digital Subscriber Line) increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, WDM elements increase. The alignment and the attachment technology are very important to fabricate the optical elements for communication. In this paper, the mechanism of rotational stage, the contact sensing unit, and integrated control circuit for the optical alignment system are studied.

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Alignment estimation performance of Multiple Design Configuration Optimization for three optical systems

  • Oh, Eun-Song;Kim, Seong-Hui;Kim, Yun-Jong;Lee, Han-Shin;Kim, Sug-Whan
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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    • pp.31.1-31.1
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    • 2011
  • In this study, we investigated alignment state estimation performances of the three methods i.e. merit function regression (MFR), differential wavefront sampling (DWS) and Multiple Design Configuration Optimization (MDCO). The three target optical systems are 1) a two-mirror Cassegrain system for deep space Earth observation, 2) intermediate size three-mirror anastigmat for Earth ocean monitoring, and 3) extremely large segmented optical system for astronomical observation. We ran alignment state estimation simulation for several alignment perturbation cases including 1mm to 10mm in decenter and from 0.1 to 1 degree in tilt perturbation error for the two-mirror Cassegrain system. In general, we note that MDCO shows more competitive estimation performance than MFR and DWS. The computational concept, case definition and the simulation results are discussed with implications to future works.

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