• 제목/요약/키워드: crystal cells

검색결과 471건 처리시간 0.032초

Time-Resolved Infrared Spectroscopy of Molecular Reorientation During FLC Electro-Optic Switching

  • Jang, Won-Gun;Clark, Noel A.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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    • pp.1112-1117
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    • 2003
  • Polarized Fourier transform infrared (IR) absorption is used to probe molecular conformation in a ferroelectric liquid crystal (FLC) during the reorientation induced by the external field. Spectra of planar aligned cells of FLC W314 are measured as functions of IR polarizer orientation and electric field applied to the FLC. The time evolution of the dichroism of the absorbance due to biphenyl core and alkyl tail molecular vibration modes, is observed. Static IR dichroism experiments show a W314 dichroism structure in which the principal axis of dielectric tensor from molecular core vibration are tilted further from the smectic layer normal than those of the tail. This structure indicates the effective binding site in which the molecules are confined in the Sm-C phase has, on average, "zig-zag" shape and this zig-zag binding site structure is rigidly maintained while the molecular axis rotates about the layer normal during field-induced switching.

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Suppression of silicon clusters using a grid mesh under DC bias

  • Kim, Yonwon;Kang, Jun
    • Journal of Advanced Marine Engineering and Technology
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    • 제41권2호
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    • pp.146-149
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    • 2017
  • Si clusters generated during the plasma chemical vapor deposition (CVD) process have a great influence on the quality of the fabricated films. In particular, in hydrogenated amorphous silicon thin films (a-Si:H) used for thin film solar cells, Si clusters are mainly responsible for light-induced degradation. In this study, we investigated the amount of clusters incorporated into thin films using a quartz crystal microbalance (QCM) and specially designed cluster eliminating filters, and investigated the effect of the DC grid mesh in preventing cluster incorporation. Experimental results showed that as the applied voltage of the grid mesh, which is placed between the electrode and the QCM, decreased, the number of clusters incorporated into the film decreased. This is due to the electrostatic force from the grid mesh bias, and this method is expected to contribute to the fabrication of high-quality thin films by preventing Si cluster incorporation.

Crystal Structure of TTC0263, a Thermophilic TPR Protein from Thermus thermophilus HB27

  • Lim, Hyosun;Kim, Kyunggon;Han, Dohyun;Oh, Jongkil;Kim, Youngsoo
    • Molecules and Cells
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    • 제24권1호
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    • pp.27-36
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    • 2007
  • The hypothetical protein TTC0263 of Thermus thermophilus HB27 is a thermophilic tetratricopeptide repeat (TPR)-containing protein. In the present study, the TPR region (residues 26-230) was resolved at $2.5{\AA}$ with R-factors of $R/R_{free}$ = 23.6%/28.6% $R/R_{free}=23.6%/28.6%$. TTC0263 consists of 11 helices that form five TPR units. Uniquely, it contains one atypical "extended" TPR (eTPR) unit. This comprises extended helical residues near the loop region of TTC0263, such that the helical length of eTPR is longer than that of the canonical TPR sequence. In addition, the hybrid TPR domain of TTC0263 possesses oligomer-forming characteristics. TPR domains are generally involved in forming multi-subunit complexes by interacting with each other or with other subunit proteins. The dynamic structure of TTC0263 described here goes some way to explaining how TPR domains mediate the formation of multi-subunit complexes.

편광측정법을 이용한 광전류 센서의 온도특성 (Temperature Characteristic of Optical Current Transformer Used Porlarimetric Method)

  • 박상만;안병립;원우식;우형관;이성갑
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.1430-1431
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    • 2008
  • In this paper, a optical current transformer has been designed and favricated to improve temperature stability caused materials properties and insulation in measuring system, suing single crystal as faraday effect cells. We used 850[nm] Laser diode as the light source and PIN Photodiode as receiver. For the experiment, the temperature transformation device make by aluminum. The range of current was from 0[A]$\sim$1600[A] and the range of temperature was from -20[$^{\circ}C$] to 50[$^{\circ}C$]. In a same experimental condition magnitude increased input current increase follow by increasing proportion of input current. The result of this study shows that characteristics of OCT are good, and it can be reflected for practical optical sensors.

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Syntheses of Cu-In-Ga-Se/S nano particles and inks for solar cell applications

  • Jung, Duk-Young
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.295-295
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    • 2010
  • Nanoparticles of the compound semiconductor, Cu(In, Ga)Se2 (CIGS), were synthesized in solution under ambient pressure below $100^{\circ}C$ and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption spectroscopy and energy-dispersive X-ray (EDX) analyses. These materials have chalcopyrite crystal structures and the particle sizes less than 100 nm. Synthetic conditions were studied for the crystallized CIGS nanoparticles formation to prevent from side products of Cu2Se, Cu2-xSe, and CuSe etc. The single phase CIGS nanoparticles were applied to coating of thin films photovoltaic cells. The electro deposition of CIGS thin films is also a good non-vacuum technology and under investigation. In aqueous solutions, the different chemical compositions of CIGS thin films were obtained, depending on pH, concentration of starting materials and deposition potentials. The surface morphology of the prepared CIGS thin films depends on the complexing ligands to the solutions during the electrochemical deposition.

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Characterization of bacillus thuringiensis isolates form soil in wonju area

  • Yoo, Kwan-Hee;Kim, Soo-Young;Ho, Kang-Min;Cho, Myung-Hwan;Lee, Hyung-Hoan
    • Journal of Microbiology
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    • 제34권4호
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    • pp.370-373
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    • 1996
  • Three strains (KW-1, KW-14, KW-15) of Bacillus thuringiensis were isolated from soil in Wonju area and characterized. The three strains produced parasporal inclusion bodies (crystals) and spores in their cells. The KW-1 strain produces spherical crystals. The crystals of strain KW-14 are bipyramidal crystal. The KW-15 strain harbors irregular crystals. Only minor biochemical characteristics of the three isolates were different and distinctive, however general characteristics were similar to the known serotypes of B. thuringiensis. Three strains were resistant to penicilin G, oxacillin and cephalothin. Three strains were highly toxic to Bombyx mori larvae, but not to the Culex pipiens larvae.

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붕소가 도핑된 다이아몬드 전극을 이용한 생체화학물질의 검출 (Detection of Bio-chemical by Boron-doped Diamond Electrode)

  • 김규식;;;박수길
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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    • pp.569-572
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    • 2001
  • Selective. highly stable determination of epinephrine(adrenalin) was achieved in cyclic voltammetric measurement carried out at electrochemically treated conductive boron-doped diamond electrode. Boron-doped diamond electrodes were prepared on single crystal Si wafers by microwave plasma chemical vapor deposition and $B_{2}O_{3}$ was dissolved in acetone/methanol(9:1) mixture solution so that the B/C weight ratio ca. $10^{4}ppm$. Epinephrine is a kind of catecholamines, which secreted from adrenal marrow cells. The serious problem to detection of epinephrine is the interference phenomena of electroactive constituent. including AA. In this study. electrochemical treatment of BDD was carried out to discriminate between epinephrine and AA responses. Experimental results showed that the peak potential of AA oxidation shift to the positive direction and the oxidation peak of epinephrine was unchanged. The effect of electrochemical treatment was maintained up to 40hrs.

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Electrochemical Properties and Structural Analysis of Carbon-Coated Silicon Anode for Lithium Secondary Batteries

  • Kim, Hyung-Sun;Chung, Kyung-Yoon;Cho, Byung-Won
    • 전기화학회지
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    • 제11권1호
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    • pp.37-41
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    • 2008
  • The effects of carbon-coated silicon anode on the electrochemical properties and structural change were investigated. The carbon-coated silicon powders have been prepared by thermal decomposition under argon/10wt% propylene mixed gas flow at $700^{\circ}C$. The surface and crystal structure of the synthesized materials were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Lithium cells with electrodes made from the uncoated and the carbon coated silicon anode were assembled and tested. The carbon-coated silicon particles merged together well after the insertion/extraction of lithium ions, and showed a relatively low irreversible capacity compared with the uncoated silicon particle.

Hepatic extraskeletal osteosarcoma with systemic metastasis in a dog

  • Johnson, Crystal;Kim, Yongbaek
    • 대한수의학회지
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    • 제53권1호
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    • pp.61-64
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    • 2013
  • A ten-year-old dog was presented with pancreatitis and increased hepatic enzymes. On necropsy a large firm mass was observed in the liver extending to the gall bladder. Smaller masses with similar texture were found in multiple organs including lung, stomach, pancreas, lymph nodes, omentum, and mesentery. Neoplastic cells were spindle shaped with prominent osteoid production and occasional trabeculae of woven bone. Tumor cell emboli were observed in the blood vessels and lymphatics of the omentum and stomach. Hepatic osteosarcoma with systemic metastasis is very rare and may serve to broaden the diagnostic spectrum of hepatic and pancreatic diseases in dogs.

용액기반 투명전극 분말 재료 연구 동향 (Research Trends in Powder Materials for Solution-based Transparent Conducting Electrode)

  • 구본율;안효진
    • 한국분말재료학회지
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    • 제24권2호
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    • pp.153-163
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    • 2017
  • Transparent conducting electrodes (TCEs) are attracting considerable attention as an important component for emerging optoelectronic applications such as liquid crystal displays, touch panels, and solar cells owing to their attractive combination of low resistivity (<$10^{-3}{\Omega}cm$) and high transparency (>80%) in the visible region. The solution-based process has unique properties of an easy fabrication procedure, scalability, and low cost compared to the conventional vacuum-based process and may prove to be a useful process for fabricating TCEs for future optoelectronic applications demanding large scale and flexibility. In this paper, we focus on the introduction of a solution-based process for TCEs. In addition, we consider the powder materials used to fabricate solution-based TCEs and strategies to improve their transparent conducting properties.