• 제목/요약/키워드: crystal defect

검색결과 282건 처리시간 0.025초

Fabrication of Large-Area Photovoltaic Crystal with Modified Surface Using Trimethoxysilyl Propyl Methacrylate (TMSPM) for Solar Cell Protection

  • Kang, Kwang-Sun
    • Current Photovoltaic Research
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    • 제2권3호
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    • pp.84-87
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    • 2014
  • Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.

테라헤르츠용 공기유도 광결정 도파로 (Air-guiding photonic crystal waveguides for terahertz radiation)

  • 조민수;박홍규;한연호;한해욱
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2006년도 하계종합학술대회
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    • pp.69-70
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    • 2006
  • Air-guided single-mode propagation of THz radiation in a photonic crystal waveguide (PCW) has been experimentally demonstrated for the first time. The PCW has been fabricated by introducing an air defect at the center of an air/Si 1D photonic crystal. By using a THz time-domain spectroscopic technique, we have experimentally shown that the guiding mechanism of the air-guiding PCW is the photonic bandgap effect.

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Diamond-Like-Carbon 박막표면에 UV 배향법을 이용한 액정 배향 효과에 관한 연구 (A Study on Liquid Crystal Alignment effects by UV Alignment Method on a Diamond-Like-Carbon Thin Film Surface)

  • 황정연;조용민;서대식
    • 한국전기전자재료학회논문지
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    • 제16권3호
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    • pp.214-218
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    • 2003
  • We studied the nematic liquid crystal (NLC) aligning capabilities by the UV alignment method on a diamond like carbon (DLC) thin film surface A good LC alignment by UV exposure on the DLC thin film surface at 200${\AA}$ of layer thickness was achieved. Also, a good LC alignment by the UV alignment method on the DLC thin film surface was observed at annealing temperature of 180$^{\circ}C$. However, the alignment defect of the NLC was observed above annealing temperature of 200$^{\circ}C$. Consequently, the good thermal stability of LC alignment by the UV alignment method o the DLC thin film surface can be achieved.

DLC 박막을 이용한 액정 배향 효과 (Liquid Crystal Alignment Effects using a DLC Thin Film)

  • 조용민;황정연;서대식;노순준;이대규;백흥구
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.346-349
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    • 2001
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of diamond like carbon (DLC) thin film. A high pretilt angle of about 4$^{\circ}$ was measured by ion beam(IB) exposure on the DLC thin film surface. A good LC alignment was observed by the IB alignment method on the DLC thin film surface at annealing temperature of 200$^{\circ}C$, and the alignment defect of the NLC was observed above annealing temperature of 220$^{\circ}C$ . Consequently, the high NLC pretilt angle and the good thermal stability of LC alignment can be achieved by the IB alignment method on the DLC thin film surface.

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새로운 광중합법을 이용한 N-(phenyl)maleimide 단독 중합체 광폴리머 표면을 인용한 액정 배향 효과 (Liquid Crystal Alignment Effects on the New Homopolymerized N-(phenyl)male iron ids Photopolymer Surface)

  • 황정연;서대식;김준영;김태호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.117-120
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    • 2001
  • A new photoalignment material PFCPMI, poly [4-(fluorocinnamate) phenylmaleimide], was synthesized and the nematic liquid crystal (NLC) aligning capabilities on the photopolymer surface. The NLC pretilt angle generated by non-UV filter method on the PFCPMI surface was higher than that of the UV filter method. A good LC alignment by non-UV filter method was observed at 150\`c of annealing temperature. However, the alignment defect of the NLC by UV filter method was measured above 150$^{\circ}C$ of annealing temperature. Consequently, the high pretilt angle and the good LC alignment in NLC using non-UV filter method can be achieved.

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N-(phenyl)maleimide 단독 중합체 광폴리머를 이용한 액정 배향 효과 (Liquid Crystal Alignment Effects on the Homopolymerized N-(phenyl) maleimide Photopolymer)

  • 황정연;김준영;이윤건;서대식;김태호
    • 한국전기전자재료학회논문지
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    • 제15권5호
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    • pp.423-428
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    • 2002
  • The photoalignment material PFCPMI, poly[4-(fluorocinnamate)phenylmaleimide], was synthesized and the nematic liquid crystal(NLC) aligning capabilities on the photopolymer surface. The NLC pretilt angle geneated by non-UV filter method on the PFCPMI surface was higher than that of the UV filter method. A good LC alignment by non-UV filter method was observed at $150^{\circ}C$ of annealing temperature. However, the alignment defect of the NLC by UV filter method was measured above $150^{\circ}C$ of annealing temperatue. Consequently, the high pretilt angle and the good LC alignment in NLC using non-UV filter method can be acheived.

Diamond-like Carbon 박막을 이용한 액정 배향 효과 (Liquid Crystal Alignment Effects using a Diamond-like Carbon Thin Film)

  • 황정연;조용민;서대식;노순준;이대규
    • 한국전기전자재료학회논문지
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    • 제15권5호
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    • pp.419-422
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    • 2002
  • We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a diamond like carbon (DLC) thin film. A high pretilt angle of about $3.5^{\circ}$ by ion beam(IB) exposure on the DLC thin film surface was measured. A good LC alignment by the IB alignment method on the DLC thin film surface was observed at annealing temperature of $200^{\circ}C$, and the alignment defect of the NLC was observed above annealing temperature of $220^{\circ}C$. Consequently, the high NLC pretilt angle and the good thermal stability of LC alignment by the IB alignment method on the DLC thin film surface can be achieved.

분자동력학적 방법에 의한 저 메너지 As 이온 주입에 따른 Si 기판의 결함 형성 거동에 대한 컴퓨터 모사 실험 (Computer Simulaton of Defect Formation Behaviors of Crystal-Silicon on the Low Energy Arsenic Implantation by Molecular Dynamics)

  • 정동석;박병도
    • 열처리공학회지
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    • 제13권4호
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    • pp.259-264
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    • 2000
  • In this study, we quantitatively measure the ion ranges of arsenic with energies ranging from 10 KeV to 100 KeV, implanted at $3^{\circ}$, $9^{\circ}$ $15^{\circ}$ the (100) plane, and the damage created during ion implantation. To obtain detailed information of ion range and damage distributions in low energy region where elastic collisions dominate the slowing down process, molecular dynamics computer simulation was performed and compared to the existing results. The effects of implant energy and degree on damage generation are present. The number of vacancy were calculated from the deposited energy using Kinchin-Pease equation. In the energy range 10 keV-100 keV, simulations show that the number of Frenckel pairs produced by As-ion bimbardment is 9 and incident angle dependence of the vacancy was the same but defects were distributed at different depth.

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LTCC 소재의 조성과 성형 공정에 따른 소결체의 강도 특성 (The Strength of Sintered Body with the Composition and the Forming Process of LTCC Materials)

  • 구신일;신효순;여동훈;남산
    • 한국전기전자재료학회논문지
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    • 제26권1호
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    • pp.27-32
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    • 2013
  • According to the composition of LTCC material, though it was thought that bulk defect which was made in forming process effects on the densification during the sintering, it was not reported systemically. In this study, we evaluated crystal structure, 3 point bending strength, hardness and microstructure of the samples by uniaxial pressing and tape casting using the commercial powders of the crystallizing glass and the glass/ceramic composite. In the case of glass/ceramic composite, Viox-001 powder with residual glass in the sintering, 3 point bending strength was similar regardless of forming process due to fill the bulk defect by residual glass. In the case of crystallizing glass, MLS-22, because glass phase was small in the sintering, glass did not fill the pore in the sample by uniaxial pressing process, therefore, the 3 point bending strength of it was 167 MPa. However, the 3 point bending strength of the sample by tape casting was 352 MPa and much higher. Meanwhile, crystal structure and hardness were similar regardless of forming process.

제올라이트 MFI 자일렌 분리막 연구 동향 (Review on Zeolite MFI Membranes for Xylene Isomer Separation)

  • 김동훈
    • 멤브레인
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    • 제29권4호
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    • pp.202-215
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    • 2019
  • 분자체 분리막은 분자크기의 기공을 갖는 다공성 분리막으로서 크기 또는 모양을 기반으로 혼합물을 분리하며, 높은 잠재적 에너지 효율과 뛰어난 분리능으로 많은 주목을 받아왔다. 그 중, 제올라이트 MFI 분리막은 가장 오랫동안 연구된 물질 중의 하나이며, 다양한 방면으로 개발된 기술들은 이후 다른 종류의 분자체 분리막 연구에도 많은 영향을 미쳤다. 본 총설에서는, 결정성 물질인 제올라이트 MFI의 결정 생성 및 성장을 제어하여 자일렌 이성질체 혼합물에 대한 분리막의 투과도와 선택도를 향상시킨 많은 방법들을 다룬다. 씨앗결정의 형태 제어, 결정의 효과적인 이차성장법, 씨앗결정의 코팅 방법, 결정의 방향성 제어, 이종원소 도입을 통한 결정구조의 유연성 제어, 결함 관리 등, 자일렌 이성질체 분리성능의 비약적 성능 향상을 가져온 기술들을 소개한다.