• Title/Summary/Keyword: Crystallinity value

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Mechanical evaluation of superhard Ti-Si-C-N coatings prepared by a hybrid coating system (하이브리드 코팅 시스템으로 제조된 초고경도 Ti-Si-C-N 코팅막의 기계적 특성 평가)

  • Kang S. H.;Kang M. C.;Kim K. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.178-181
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    • 2005
  • Quaternary Ti-Si-C-N coatings were deposited on WC-Co substrates by a hybrid coating system of arc ion plating (AIP) and sputtering techniques using Ti and Si targets, in an $Ar/N_2/CH_4$ gaseous mixture. The crystallinity, bending status, and microstructure of the Ti-Si-C-N coatings were measured by X-ray diffractometer (XRD) and X-ray photoelectron spectroscope (XPS), The micro-hardness of Ti(C,N) and Ti-Si-N coatings were about 30 and 40 GPa, respectively. As the Si was incorporated into Ti(C,N) coatings, the Ti-Si-C-N coatings having Si content of $8.9\;at.\%$ showed the maximum hardness value of about 55 GPa. In this work, the microstructure and mechanical properties of Ti-Si-C-N coatings were systematically investigated.

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Optical Characteristics of Spherical Phosphors for Low-Voltage FED Operation

  • Yoo, J.S.;Cho, S.H.;Hong, G.Y.;Lee, J.D.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.143-144
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    • 2000
  • The aerosol pyrolysis technique was introduced to prepare the spherical phosphors for enhancing low-voltage phosphor efficiency. The density, the shape, and the crystallinity of phosphors were controlled by thermal decomposition temperature and phosphor annealing condition. The particle size was adjusted by the precursor concentration and reactor pressure. It was fond that the efficiency of phosphors synthesized in this work was superior to the commercial products at the low-voltage excitation by 1.5 times and the screen efficiency was also higher than that of any value reported in literature.

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Dopant-Activation and Damage-Recovery of Ion-Shower-Doped Poly-Si through $PH_3/H_2$ after Furnace Annealing

  • Kim, Dong-Min;Kim, Dae-Sup;Ro, Jae-Sang;Choi, Kyu-Hwan;Lee, Ki-Yong
    • Journal of Information Display
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    • v.5 no.1
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    • pp.1-6
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    • 2004
  • Ion shower doping with a main ion source of $P_2H_x$ using a source gas mixture of $PH_3/H_2$ was conducted on excimer-laser- annealed (ELA) poly-Si. The crystallinity of the as-implanted samples was measured using a UV-transmittance. The measured value of as-implanted damage was found to correlate well with the one calculated through/obtained from TRIM-code simulation. The sheet resistance was found to decrease as the acceleration voltage increased from 1 kV to 15 kV at a doping time of 1 min. However, it increases as the acceleration voltage increases under severe doping conditions. Uncured damage after furnace annealing is responsible for the rise in sheet resistance.

Growth and characterization of Eu-doped bismuth titanate (BET) thin films deposited by sol-gel method

  • Kang Dong-Kyun;Kim Byong-Ho
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2006.05a
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    • pp.194-197
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    • 2006
  • Lead-free bismuth-layered perovskite ferroelectric europium-substituted $Bi_{4}Ti_{3}O_{12}(BTO)$ thin films have been successfully deposited on Pt/Ti/$SiO_2$/Si substrate by a sol-gel spin-coating process. $Bi(TMHD)_3,\;Eu(THMD)_3,\;Ti(OiPr)_4$ were used as the precursors, which were dissolved in 2-methoxyethanol. The thin films were annealed at various temperatures from $600^{\circ}\;to\;720^{\circ}C$ in oxygen ambient for 1 hr, which was followed by post-annealed for 1 hr after depositing a Pt electrode to enhance the electrical properties. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystallinity and surface morphology of layered perovskite phase, respectively. The remanent polarization value of the BET thin films annealed at $720^{\circ}C\;was\;25.95{\mu}C/cm^2$ at an applied voltage of 5 V.

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Physicochemical Properites of Potato Starches Crosslinked with Epichlorohydrin (Epichlorohydin으로 가교결합시킨 감자 전분의 이화학적 특성)

  • 김미라;이선자
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.1
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    • pp.132-139
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    • 1999
  • Physicochemical properties of the crosslinked potato starches of MDC(Molar Degree of Crosslinking) 0.137~3.333 treated with epichlorohydrin were examined. MDC increased proportionally as epichlorohydrin concentration increased. Water binding capacity increased but blue value decreased with increasing MDC. Gelatinization trends obtained from DSC thermograms and transmittance showed that the gelatinization temperature of the crosslinked potato starch was higher than that of native potato starch, but there was no significant difference among the crosslinked potato starches. Solubility and swelling power decreased with increasing MDC. X ray diffraction patterns and scanning electron micrographs showed that the crosslinking of starch did not affect the crystallinity and the granule shape of starch.

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A Study on the Crystal Structure and Mechanical Properties of Isotactic Polypropylene (i-PP) Films (Isotactic Polypropylene (i-PP) film의 구조변화와 물성에 관한 연구)

  • Park, Myung-Soo;Kwon, Oh-Hyuk
    • Textile Coloration and Finishing
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    • v.9 no.6
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    • pp.18-25
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    • 1997
  • The change of crystalline structure and mechanical properties of i-PP films which had before isothermally annealed at various temperature and times have been studied. The following results were abtain The crystallinity and crystallite size of the samples showed increasing above the annealing temperature of 13$0^{\circ}C$ and these are equilibrated after an annealing time of 30min. When the crystalline form was at annealling condition were below 13$0^{\circ}C$, 2min, subsequently achieving an $\alpha$, $\beta$ mixing form and at 13$0^{\circ}C$, 10min, the crystalline form entered an $\alpha$ form transition. It is achieved a typical $\alpha$ form at 15$0^{\circ}C$. The value of T'm was increasing until 13$0^{\circ}C$ but it was not founded at 15$0^{\circ}C$. The slopes which represented crystalline form in an Avrami plot differed from each other within the range of this experiment.

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Properties of Rice Flours Prepared from Domestic High Amylose Rices (국내산 고아밀로오스 쌀가루의 특성)

  • Choi, Sin-Young;Shin, Mal-Shick
    • Korean Journal of Food Science and Technology
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    • v.41 no.1
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    • pp.16-20
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    • 2009
  • To develop health functional foods using high amylose rice flours, the properties of flours prepared from domestic high amylose rice varieties, Goamy2 and Goamy, and imported rice from Thailand were investigated. After soaking the rice grains and drying, the dry-milled rice flours were passed through a 120-mesh sieve. The protein and total starch contents of the Goamy2 rice flour were lowest, but its crude lipid and ash contents were highest among the flours. In addition, apparent amylose content, water binding capacity, and total dietary fiber were highest in the Goamy2 flour (36.2, 255.0, and 9.2%, respectively). The Thai rice flour had the highest swelling power, whereas the Goamy2 flour had the lowest swelling power and solubility. By Rapid visco-analysis, the Thai flour showed the highest peak and total setback viscosities and lowest breakdown viscosity. The pasting pattern of the Goamy2 flour was different from that of the other flour, where low viscosity was maintained during heating and cooling. Goamy and Thai rice flours showed an A type crystallinity, but Goamy2 flour showed a B type crystallinity similar to high amylose maize starch. The Goamy2 flour presented a dull and yellowish color, and the lowest lightness (L) value and the highest yellowness (+b) value.

Low-Temperature Characteristics of Type 4 Composite Pressure Vessel Liner according to Rotational Molding Temperature (타입 4 복합재 압력용기 라이너의 회전 성형 온도에 따른 저온 특성)

  • Jung, Hong-Ro;Park, Ye-Rim;Yang, Dong-Hoon;Park, Soo-Jeong;Kim, Yun-Hae
    • Composites Research
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    • v.35 no.3
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    • pp.147-152
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    • 2022
  • Low-temperature characteristics according to internal temperature conditions during rotational molding of Type 4 pressure vessel liners were studied in this paper. Since rotational molding has a sensitive effect on the formability of the liner depending on the temperature conditions, the temperature conditions for the polyamide used should be accurately set. The structural changes of polyamide as the liner material was analyzed the surface by atomic force microscope (AFM), and the crystallinity measured with a differential scanning calorimeter (DSC) is used to evaluate the change of the mechanical strength value at low temperature. In addition, the formability of the liner was confirmed by observation of the yellow index inside the liner. As a result, as the melting range of the internal temperature becomes wider, the yellow index shows a lower value, and the elongation and impact characteristics at low temperatures are improved. It was also confirmed that the structure of the polyamide was uniform and the crystallinity was high by AFM and DSC. These experimental results contribute to the improvement of characteristics at low temperatures due to changes in temperature conditions during rotational molding.

Physicochemical Properties of Cross-linked Apios Starch (가교결합 아피오스 전분의 이화학적 특성)

  • Park, Mi Hye;Kim, Meera
    • Journal of the East Asian Society of Dietary Life
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    • v.24 no.3
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    • pp.400-406
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    • 2014
  • Apios (Apios americana Medikus) belongs to Leguminosae and is called 'American groundnut', 'Potato bean', and 'wild bean'. Apios is native to the Northern United States but is not widely distributed in Korea. In this study, cross-linked apios starch was prepared by reaction with epichlorohydrin, followed by characterization. FT-IR spectroscopy confirmed the degree of cross-linking of apios starch. X-ray diffraction patterns of native apios showed typical 'A' type as peaks at 15.1, 17.1, 17.9 and $23.2^{\circ}$, and cross-linking did not affect relative crystallinity and X-ray diffraction patterns of the starch. Scanning electron micrographs showed that apios starch granules were smooth with a globular shape, and there was little damage to starch granules after cross-linking. The lightness value of cross-linked apios starch was lower than that of native apios starch, whereas the redness value was not significantly different between cross-linked apios starch and native apios starch. Blue value showed that cross-linking of starch did not affect the iodine reaction of starch.

Photoelectrocatalytic Degradation of Dyes in Aqueous Solution Using CNT/TiO2 Electrode

  • Zhang, Feng-Jun;Liu, Jin;Chen, Ming-Liang;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
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    • v.46 no.3
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    • pp.263-270
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    • 2009
  • The effect of photoelectrocatalytic (PEC) degradation for different dyes with the CNT/$TiO_2$ electrode was studied. The prepared electrode was characterized with surface properties, structural crystallinity, elemental identification, and PEC activity. The $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine CNT. This indicated the blocking of micropores on the surface of CNT, which was further supported by observation via FESEM. XRD patterns of the composites showed that the CNT/$TiO_2$ composite contained a mixing anatase and rutile phase. EDX spectra showed the presence of C, O and Ti peaks for all samples. The decomposition efifciency of the prepared electrode was evaluated by the PEC degradation of three dyes (methylene blue (MB), rhodamine B (RH.B), methyl orange (MO)). The variations of the FT-IR spectra and pH value of dye solutions were measured during the PEC system; it was found that the CNT/$TiO_2$ electrode has better PEC degradation for MB solution than that of RH.B and MO. The proposed degradation mechanism was present.