• 제목/요약/키워드: molecular alignment

검색결과 276건 처리시간 0.033초

Wide-Viewing Characteristics of Self-Formed Micro-Domains in a Liquid Crystal Display with Dielectric Surface Gratings

  • Yoon, Tae-Young;Park, Jae-Hong;Yu, Chang-Jae;Lee, Sin-Doo
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2002년도 International Meeting on Information Display
    • /
    • pp.452-455
    • /
    • 2002
  • We demonstrate the wide-viewing characteristics of a twisted nematic liquid crystal display (LCD) with self-formed micro-domains through the topographical alignment and fringe field effects of dielectric surface gratings (DSG). The mutual optical compensation between micro-domains within each pixel eliminates the contrast inversion phenomenon of TN mode without complex surface treatments.

  • PDF

폴리이미드막표면위에 경사진 자외선 조사를 이용한 네마틱 액정의 배향에 관한 연구 (A Study on Alignment of Nematic Liquid Crystal by Using Slanted Non-polarized Ultraviolet Light Irradiation on Polyimide Film)

  • 서대식;황율연;이보호
    • E2M - 전기 전자와 첨단 소재
    • /
    • 제10권5호
    • /
    • pp.461-466
    • /
    • 1997
  • In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.

  • PDF

폴리이미드막을 이용한 광배향 효과에 관한 연구 (A Study on Effect of Photo-alignment in Nematic Liquid Crystal on Polyimide Film)

  • 서대식;황율연
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 1997년도 춘계학술대회 논문집
    • /
    • pp.116-119
    • /
    • 1997
  • We investigated new type non-robbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) irradiation on polyimide (Pl) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV irradiation on Pl surface. We successfully obtained that the pretilt ang1e of NLC is generated about 3 degree in the LC cells by using slanted non-polarized UV irradiation with 70 degree on Pl surface. We consider that the pretilt angle generation for NLC is attributed to interaction between the LC molecular and the PI surface. We conclude that the uniform LC alignment is attributed to anisotropic dispersion force effect due to photo depolymerization of polymer on Pl surface.

  • PDF

An in Depth Study of Crystallinity, Crystallite Size and Orientation Measurements of a Selection of Poly(Ethylene Terephthalate) Fibers

  • Karacan Ismail
    • Fibers and Polymers
    • /
    • 제6권3호
    • /
    • pp.186-199
    • /
    • 2005
  • A selection of commercially available poly(ethy1ene terephtha1ate) fibers with different degrees of molecular alignment and crystallinity have been investigated utilizing a wide range of techniques including optical microscopy, infrared spectroscopy together with thermal and wide-angle X-ray diffraction techniques. Annealing experiments showed increased molecular alignment and crystallinity as shown by the increased values of birefringence and melting enthalpies. Crystallinity values determined from thermal analysis, density, unpolarized infrared spectroscopy and X-ray diffraction are compared and discussed in terms of the inherent capabilities and limitations of each measurement technique. The birefringence and refractive index values obtained from optical microscopy are found to decrease with increasing wavelength of light used in the experiments. The wide-angle X-ray diffraction analysis shows that the samples with relatively low orientation possess oriented non-crystalline array of chains whereas those with high molecular orientation possess well defined and oriented crystalline array of chains along the fiber axis direction. X-ray analysis showed increasing crystallite size trend with increasing molecular orientation. SEM images showed micro-cracks on low oriented fiber surfaces becoming smooth on highly oriented fiber surfaces. Excellent bending characteristics were observed with knotted fibers implying relatively easy fabric formation.

편광법을 이용한 LCD 편광판과 보상판의 광축 정렬오차 측정 (Technique of measuring optic axis off-alignment error for LCD polarizing and compensating plates by using a polarimetry)

  • 안성혁;김상준;김상열
    • 한국광학회지
    • /
    • 제15권6호
    • /
    • pp.527-530
    • /
    • 2004
  • 회전검광자방식 편광분석방법을 이용하여 LCD (liquid crystal display) 편광판에 부착되어 있는 보상판의 느린축이 편광판의 투과축 대비 틀어진 각도를 0.1도 이내로 정밀하게 측정할 수 있는 방법을 제안하였다. 본 방법을 이용하면 보상판을 LCD 편광판과 접합하는 공정에서 발생하는 광축정렬의 오차를 줄일 수 있고 궁극적으로 LCD의 화질을 일정하게 유지, 관리하는데 기여할 수 있을 것으로 기대된다.

서열 정렬 알고리즘의 연구 동향 (A Survey of Sequence Alignment Algorithms)

  • 성종희;김동규
    • 한국멀티미디어학회:학술대회논문집
    • /
    • 한국멀티미디어학회 2003년도 춘계학술발표대회논문집
    • /
    • pp.571-574
    • /
    • 2003
  • 서열 정렬(sequence alignment)은 새로운 서열의 기능적, 구조적, 진화적 분석을 용이하게 하기 때문에 분자 생물학(molecular biology) 등에서 널리 사용된다. 지금까지 서열 정렬 알고리즘들에 대한 연구는 활발히 진행되어 왔다. 특히, 생물학 데이터양의 기하급수적인 증가와 전체 유전체 서열의 분석이 이루어진 종(species)들이 증가하면서, 보다 빠르고 정확하게 서열 정력을 수행하는 알고리즘이 필요하게 되었다. 본 논문에서는 동적 프로그래밍 방식에서부터 전체 유전체 서열 알고리즘에 이르기까지 서열 정렬 알고리즘의 연구 동향을 분석하고자 한다.

  • PDF

Para-sexiphenyl 유기 전기발광소자의 배향 처리 효과 (Molecular alignment effect of para-sexiphenyl organic electroluminescent devices)

  • 이용수;이재혁;박재훈;최종선
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
    • /
    • pp.443-445
    • /
    • 2000
  • The high mobilitie sallow larger current to be reached under operation in the space charge limited conduction region, hence facilitate access to higher luminance as required for passive matrix panel. In this work, we have investigated the molecular alignment control effect of organic electroluminescent devices. we aligned the p-sexiphenyl(6p) using a simple rubbing treatment. We studied the anisotropic optical properties and electrical characteristics.

  • PDF

Enhancement of Molecular Orientation of Liquid Crystal on Photoreactive Polymers by using Non-Photoreactive Naphthalenic Polyimide

  • Hah, Hyun-Dae;Sung, Shi-Joon;Cho, Ki-Yun;Kim, Won-Sun;Jeong, Yong-Cheol;Park, Jung-Ki
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
    • /
    • pp.1169-1172
    • /
    • 2004
  • Polyimides are blended with photoreactive polymers in order to improve the thermal stability of molecular orientation of photoreactive groups induced by polarized UV irradiation. The polyimide/photopolymer blends can be applied for the photo-induced liquid crystal alignment layers. However, the polyimides are also decomposed by UV irradiation and this may have the negative effect on the orientation of liquid crystals. In order to elucidate the influence of polyimide on the molecular orientation of liquid crystal, non-photoreactive naphthalenic polyimide (1,4,5,8-naphthalene tetracarboxylic dianhydride} was selected for the blend alignment layers. We prepared the blends of photo-reactive coumarin polymers and naphthalenic polyimide, and investigated the orientation of liquid crystals. Thermal stability of the orientation of liquid crystals was enhanced due to the thermally stable polyimide. However, there was no other side-effect of polyimide on the orientation of liquid crystals and this might be attributed to the non-photo-reactivity of naphtahlenic polyimide.

  • PDF

Cloning and characterization of a cDNA encoding a paired box protein, PAX7, from black sea bream, Acanthopagrus schlegelii

  • Choi, Jae Hoon;Han, Dan Hee;Gong, Seung Pyo
    • 한국동물생명공학회지
    • /
    • 제36권4호
    • /
    • pp.314-322
    • /
    • 2021
  • Paired box protein, PAX7, is a key molecule for the specification, maintenance and skeletal muscle regeneration of muscle satellite cells. In this study, we identified and characterized the cDNA and amino acid sequences of PAX7 from black sea bream (Acanthopagrus schlegelii) via molecular cloning and sequence analysis. A. schlegelii PAX7 cDNA was comprised of 1,524 bp encoding 507 amino acids and multiple sequence alignment analysis of the translated amino acids showed that it contained three domains including paired DNA-binding domain, homeobox domain and OAR domain which were well conserved across various animal species investigated. Pairwise Sequence Alignment indicated that A. schlegelii PAX7 had the same amino acid sequences with that of yellowfin seabream (A. latus) and 99.8% identity and similarity with that of gilt-head bream (Sparus aurata). Molecular phylogenetic analysis confirmed that A. schlegelii PAX7 formed a monophyletic group with those of teleost and most closely related with those of the fish that belong to Sparidae family including A. latus and S. aurata. In the investigation of its tissue specific mRNA expression, the expression was specifically identified in skeletal muscle tissue and a weak expression was also shown in gonad tissue. The cultured cells derived from skeletal muscle tissues expressed PAX7 mRNA at early passage but the expression was not observed after several times of subculture.

Photosensitive Polymers: Effects of Photoreactive Group and UV-Exposure on Alignment of Liquid-Crystals on the Film Surface

  • Ree, Moon-Hor;Kim, Sang-Il;Lee, Seung-Woo
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
    • /
    • pp.41-42
    • /
    • 2000
  • Photosensitive polyimides containing cinnamoyl and coumarin side groups were synthesized in a high molecular weight, giving a good quality of films. Nematic liquid-crystal (LC) molecules on the film were aligned along the direction with an angle of $97-99^{\circ}$ respect to the polarization of ultraviolet (UV) light. The LC alignment was induced mainly by the photoaligned polymer chains made by the first UV-exposure even though the film was treated by multiple exposures with changing the polarization of UV light. From these results, it is concluded that the LC alignment on the film is induced by the photodimerization rather than the trans-cis photoisomerization.

  • PDF