• Title/Summary/Keyword: mixed crystal

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Vibrational Spectroscopic Studies of Crystallization in Mixed n-Paraffins (진동분광실험을 이용한 n-Paraffin혼합물의 결정화에 관한 연구)

  • 김도균;임현주;최선남;김성수;송기국
    • Polymer(Korea)
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    • v.26 no.6
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    • pp.752-758
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    • 2002
  • FTIR, FT-Raman, and X-ray diffraction techniques were used to determine chain segregations and lamellar structures of the mixed binary n-paraffins with different chain lengths. The results of three different techniques, infrared spectroscopic studies of crystal field splitting, the Raman longitudinal acoustic mode, and the SAXS long period measurements were compared one another to understand the crystallization mechanism of separated or mixed n- paraffin lamellae.

Phase behaviors, lamellar structures, and physical properties of synthetic vitamin E ceramide (Tocomide) mixed with cholesterol and linoleic acid

  • Lee, Young-Jin;Kim, Do-Hoon;Park, Ho-Sik;Kang, Hyung-Seok;Kim, Joong-Soo;Kim, Han-Kon
    • Proceedings of the SCSK Conference
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    • 2003.09b
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    • pp.357-368
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    • 2003
  • II-A isotherms and phase behaviors of 'tocomide', a newly synthesized 1,3-bis(N-(2-hydroxyethyl)-tocopherol succinylamino)-2-hydroxypropane, mixed with cholesterol and linoleic acid, was studied for its monolayer miscibility and a stable delivery formulation for antioxidant applications. The monolayer of tocomide and cholesterol was formed in a homogeneously mixed state at air-water interface. The ternary mixtures with linoleic acid showed various bulk structures, including a stable and transparent solution of thermodynamically stable lamellar phase. The lamellar structure was confirmed by the X-ray diffraction (XRD) patterns and polarized microscopy such that pure tocomide formed a liquid crystal at room temperature with a lamellar periodicity of 36.7 $\AA$(2$\theta$=2.41$^{\circ}$).

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Characterization of In(Al)GaN layer grown by mixed-source hydride vapor phase epitaxy (혼합소스 HVPE에 의해 성장된 In(Al)GaN 층의 특성)

  • Hwang, S.L.;Kim, K.H.;Jang, K.S.;Jeon, H.S.;Choi, W.J.;Chang, J.H.;Kim, H.S.;Yang, M.;Ahn, H.S.;Bae, J.S.;Kim, S.W.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.4
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    • pp.157-161
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    • 2006
  • InGaN layers on GaN templated sapphire (0001) substrates were grown by mixed-source hydride vapor phase epitaxy (HVPE) method. In order to get InGaN layers, Ga-mixed In metal and $NH_3$ gas were used as group III and group V source materials, respectively. The InGaN material was compounded from chemical reaction between $NH_3$ and indium-gallium chloride farmed by HCl flowed over metallic In mixed with Ga. The grown layers were confirmed to be InGaN ternary crystal alloys by X-ray photoelectron spectroscopy (XPS). In concentration of the InGaN layers grown by selective area growth (SAG) method was investigated by the photoluminescence (PL) and cathodoluminescence (CL) measurements. Indium concentration was estimated to be in the range 3 %. Moreover, as a new attempt in obtaining InAlGaN layers, the growth of the thick InAlGaN layers was performed by putting small amount of Ga and Al into the In source. We found the new results that the metallic In mixed with Ga (and Al) as a group III source material could be used in the growth process of the In(Al)GaN layers by the mixed-source HVPE method.

Opto-electric Properties of $ZnIn_2S_4$ single crystal thin film Grown by Hot Wall Epitaxy method (Hot Wall Epitaxy (HWE)에 의한 성장된 $ZnIn_2S_4$ 단결정 박막의 광전류 특성)

  • Hong, Kwang-Joon;Lee, Sang-Youl
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.71-72
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    • 2006
  • The stochiometric mixture of evaporating materials for the $ZnIn_2S_4$ single crystal thin film was prepared from horizontal furnace. To obtain the $ZnIn_2S_4$ single crystal thin film. $ZnIn_2S_4$ mixed crystal was deposited on throughly etched semi-insulating GaAs(100). In the Hot Wall Epitaxy(HWE) system. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $ZnIn_2S_4$ single crystal thin film, we have found that the values of spin orbit splitting ${\Delta}So$ and the crystal field splitting ${\Delta}Cr$ were 0.0148 eV and 0.1678 eV at $10_{\circ}K$, respectively.

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A Change of Thermal Expansion Coefficient according to Li2O-added Porcelain for Dental Zirconia (치과용 지르코니아 도재의 Li2O 첨가에 따른 열팽창계수 변화)

  • Yoon, Han-Sok
    • Journal of Technologic Dentistry
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    • v.31 no.4
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    • pp.25-30
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    • 2009
  • Zirconia($ZrO_2$) has attracted much attention in science and technology because of its high refractive index, high melting temperature, hardness, low thermal conductivity and corrosion barrier properties. And it is widely used as the dental restoration material because of its esthetic appearance. In this research, we analyzed the particle size and composition of the imported dental porcelain for zirconia. And the glass frit was produced. To decrease the glass transition temperature and softening temperature of the glass frit, $Li_2O$ was added into it and the effect of $Li_2O$ on the firing temperature was researched. Then the glass which contains leucite crystal with a high coefficient of thermal expansion(CTE) was manufactured and it was mixed with the glass frit to control the CTE. The phase composition were analyzed using the X-ray diffraction. The morphologies of the samples were observed by the scanning electron microscope. The 4wt% $Li_2O$-added glass frit has the optimal glass transition temperature and softening temperature. And 6 wt% leucite crystal was mixed with the glass frit to control the CTE. From the experimental results of crystallization, the crystal phase was found only leucite crystal.

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The Study of Growth and Characterization of CuGaSe$_2$ Sing1e Crystal Thin Films for solar cell by Hot Wall Epitaxy (HWE(Hot Wall Epitaxy)에 의한 태양 전지용 박막성장과 특성에 관한 연구)

  • 홍광준
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.237-242
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    • 2001
  • The stochiometric mix of evaporating materials for the CuGaSe$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, CuGaSe$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were 610$^{\circ}C$ and 450$^{\circ}C$, respectively The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the CuGaSe$_2$ single crystal thin film, we have found that the values of spin orbit splitting Δ So and the crystal field splitting ΔCr were 91 meV and 249.8 meV at 20 K, respectively. From the Photoluminescence measurement on CuGaSe$_2$ single crystal thin film, we observed free excition (Ex) existing only high quality crystal and neutral bound exiciton (D$^{\circ}$,X) having very strong peak intensity. Then, the full-width-at-half-maximum(FWHM) and binding energy 7f neutral acceptor bound excision were 8 meV and 35.2 meV, respectivity. By Haynes rule, an activation energy of impurity was 355.2 meV

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Recovery of High Concentrated Phosphates using Powdered Converter Slag in Completely Mixed Phosphorus Crystallization Reactor (완전혼합형 정석탈인반응조에서 미분말 전로슬래그를 이용한 고농도 인의 회수)

  • Kim, Eung-Ho;Yim, Soo-Bin;Jung, Ho-Chan;Lee, Eok-Jae;Cho, Jin-Kyu
    • Journal of Korean Society on Water Environment
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    • v.21 no.1
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    • pp.59-65
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    • 2005
  • A phosphate recovery system from artificial wastewater was developed using a completely mixed phosphorus crystallization reactor, in which powdered converter slag was used as a seeding crystal. In preliminary test, the optimal pH range for meta-stable hydroxyapatite crystallization for high phosphorus concentration was observed to be 6.0 to 7.0, which was different from the conventionally known pH range (8.0~9.5) for effective crystallization in relatively low phosphorus concentration less than 5 mg/L. The average phosphorus removal efficiency in a lab-scaled completely mixed crystallization system for artificial wastewater with about 100 mg/L of average $PO_4-P$ concentration was shown to be 60.9% for 40 days of lapsed time. XRD analysis exhibited that crystalline of hydroxyapatite formed on the surface of seed crystal, which was also observed in SEM analysis. In EDS mapping analysis, composition mole ratio (=Ca/P) of the crystalline was found to be 1.78, indicating the crystalline on the surface of seed crystal is likely to be hydroxyapatite. Particle size distribution analysis showed that average size of seed crystal increased from $28{\mu}m$ up to $50{\mu}m$, suggesting that phosphorus recycling from wastewater with high phosphorus concentration can be successfully obtained by using the phosphorus crystallization recovery system.

Growth and Optical Properties for $AgGaSe_2$ Single Crystal Thin Films by Hot Wall Epitaxy (Hot Wall Epitaxy (HWE)법에 의한$AgGaSe_2$ 단결정 박막 성장과 광학적 특성)

  • Hong, Kwang-Joon;Back, Seoung-Nam
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.124-127
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    • 2003
  • The stochiometric $AgGaSe_2$ polycrystalline mixture of evaporating materials for the $AgGaSe_2$ single crystal thin film was prepared from horizontal furnance. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal and semi-insulating GaAs(100) wafer were used as source material and substrate for the Hot Wall Epitaxy (HWE) system, respectively. The source and substrate temperature were fixed at $630^{\circ}C$ and $420^{\circ}C$, respectively. The thickness of grown single crystal thin films is $2.1{\mu}m$. The single crystal thin films were investigated by photoluminescence and double crystal X-ray diffraction(DCXD) measurement. From the photoluminescence measurement of $AgGaSe_2$ single crystal thin film, we observed free excition ($E_x$) observable only in high quality crystal and neutral bound excition ($D^{\circ}$,X) having very strong peak intensity. And, the full width at half maximum and binding energy of neutral donor bound excition were 8 meV and 14.1 meV, respectively. By Haynes rule, an activation energy of impurity was 141 meV.

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