• Title/Summary/Keyword: X-ray diffraction patterns

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Biodegradation of Cotton/Polyester Blends (면/폴리에스터 혼방직물의 생분해성 평가)

  • Lee, Seung-Hyun;Park, Chung-Hee;Im, Seung-Soon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.2
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    • pp.347-355
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    • 2005
  • Biodegradability of cotton/polyester blend fabric was investigated employing activated sluge test, soil burial test and enzyme hydrolysis. Surface changes of the degraded sample were observed through a microscopy. Changes in X-ray diffraction patterns and crystallinity were examined using X-ray diffractometer. Experimental results revealed that biodegradability of cotton/polyester blend fabric was proportional to the blending ratio of cotton, not showing any synergy effect. Polyester 100% hardly degraded in this study. Through the comparison of the experimental method it was shown that the biodegradabilities determined from activated sludge test and enzymatic hydrolysis except soil burial test were linearly related to the blending ratio of cotton in the blent fabrics. It is probably because the biodegradability determined from the retention of tensile strength of fabrics buried in soil was affected by the stress distribution of polyesters throughout the fabric. From the microscopic observations it was revealed that fungi were grown on the fabric surface and the colors turned yellow, brown and black. X-ray diffraction patterns showed that the heights of crystalline peak coming from cotton part in blend fabrics decreased whereas those coming from polyester part increased comperatively as time passed by. Crystallinities of cotton 100% fabric increased slightly at the begining and then decreased continuously.

Microstructure and Dielectric Properties of (Ba1-xCax)(Ti0.85Zr0.12Sn0.03)O3 Ceramics ((Ba1-xCax)(Ti0.85Zr0.12Sn0.03)O3계 세라믹스의 미세구조 및 유전 특성)

  • Shin, Sang-Hoon;Yoo, Ju-Hyun;Shin, Dong-Chan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.12
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    • pp.797-802
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    • 2014
  • In this study, in order to develop the capacitor composition ceramics with the good dielectric properties, $(Ba_{1-x}Ca_x)(Ti_{0.85}Zr_{0.12}Sn_{0.03})O_3$ (abbreviated as BCTZ) ceramics were prepared by the conventional solid-state reaction method. The effects of Ca substitution on the microstructure and dielectric properties was investigated. The X-ray diffraction patterns demonstrated that all the specimens showed perovskite phase, and secondary phases are indicated in the measurement range of X-ray diffraction. Also, all the specimens indicated an rhombohedron phase structure. It was identified from the X-ray diffraction patterns that the secondary phase formed in grain boundaries and then decreased the dielectric properties. For all the specimens, observed one peak was tetragonal cubic phase transition temperature($T_c$), which is located in the vicinity of room temperature.

Photosensor of properties for CdSe thin film grown by Chemical Bath Deposition Method (Chemical Bath Deposition 방법으로 CdSe 박막 성장과 광센서 특성)

  • Hong, Kwang-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.04b
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    • pp.1-4
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    • 2004
  • Polycrystalline CdSe thin films were grown on ceramic substrate using a chemical bath deposition(CBD)method. They were annealed at various temperature and X-ray diffraction patterns were measured by X-ray diffractometer in order to study CdSe polycrystal structure. Using extrapolation method of X-ray diffraction patterns for the CdSe samples annealed in $N_2$ gas at $450^{\circ}C$ it was found hexagonal structure whose lattice parameters $a_0$ and $c_0$ were $4.302{\AA}$ and 7.014 ${\AA}$, respectively. Its grain size was about 0.3 ${\mu}m$. Hall effect on this sample was measured by Van der Pauw method and studied on carrier density and movility depending on temperature. From Hall data, the mobility was likely to be decreased by piezo electric scattering at temperature range of 33K and 200K, and by polar optical scattering at temperature range of 200K and 293K. We measured also spectral response, sensitivity$(\gamma)$, maximum allowable power dissipation and response time on these samples.

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Synthesis, Structure, and Thermal Property of Poly(trimethylene terephthalate- co-trimethylene 2,6-naphthalate) Copolymers

  • Jeong, Young-Gyu;Jo, Won-Ho;Lee, Sang-Cheol
    • Fibers and Polymers
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    • v.5 no.3
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    • pp.245-251
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    • 2004
  • Poly(trimethylene terephthalate-co-trimethylene 2,6-naphthalate)s (P(TT-co-TN)s) with various copolymer composition were synthesized, and their chain structure, thermal property and crystalline structure were investigated by using $^1$H-NMR spectroscopy, differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), respectively. It was found from sequence analysis that all the P(TT-co-TN) copolymers synthesized have a statistical random distribution of TT and TN units. It was also observed from DSC thermograms that the glass transition temperature increases linearly with increasing the TN comonomer content, whereas the melting temperature of copolymer decreases with increasing the corresponding comonomer content in respective PTT- and PTN-based copolymer, showing pseudo-eutectic melting behavior. All the samples melt-crystallized isothermally except for P(TT-co-66 mol % TN) exhibit multiple melting endotherms and clear X-ray diffraction patterns. The multiple melting behavior originates from the dual lamellar population and/or the melting-recrystallization-remelting. The X-ray diffraction patterns are largely divided into two classes depending on the copolymer composition, i.e., PTT and PTN $\beta$-form diffraction patterns, without exhibiting cocrystallization.

Synthesis and characterization of AlN nanopowder by the microwave assisted carbothermal reduction and nitridation (CRN)

  • Chun, Seung-Yeop;Chun, Myoung-Pyo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.5
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    • pp.223-228
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    • 2017
  • Aluminum nitride (AlN) powder was successfully synthesized at low temperature via carbothermal reduction and nitridation (CRN) assisted by microwave heating. The synthesis processes of AlN powder were investigated with X-ray diffraction, FE-SEM, FT-IR and TGA/DSC. Aluminum nitrate was used as an oxidizer and aluminum source, urea as fuel, and glucose as carbon source. These starting materials were mixed with D.I water and reacted in a flask at $100^{\circ}C$ for 20 minutes. After the reaction was finished, black foamy intermediate product was formed, which was considered to be an amorphous $Al_2O_3$ particles through intermediate product obtained by solution combustion synthesis (SCS) at the results of X-ray diffraction patterns and FT-IR. This intermediate product was nitridated at temperatures of $1300^{\circ}C$ and $1400^{\circ}C$ in $N_2$ atmosphere by a microwave heating furnace and then decarbonated at $600^{\circ}C$ for 2 hours in air. It should be noticed from FE-SEM images that as nitridated particles, identified as AlN from X-ray diffraction patterns, are covered with carbon residues. After decarbonating the nitridated powders, the spherical pure AlN powders were obtained without alumina and their particle sizes were dependent on the nitridating temperature with high temperature of $1400^{\circ}C$ giving large particles of around 70~100 nm.

Effect of Crystallization of Matrix Phase on the Fracture Toughness of Silicon Nitride Ceramics (질화규소 요업체의 기지상 결정화가 파괴인성에 미치는 영향)

  • 김남균;김도연;강대갑
    • Journal of the Korean Ceramic Society
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    • v.24 no.4
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    • pp.364-368
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    • 1987
  • The Si5AION7 specimens containing 20% YAG composition have been sintered and then heat treated to induce the crystallization of the matrix glassy phase. Crystallization of YAG phase during the heat treatment was detected from the X-ray diffraction patterns and the consequent changes in room temperature toughness as well as in microstructures were investigated. Almost all the glassy boundary phase were found to crystallize even after 5 minutes of heat treatment and the KC at room temperature decreased accordingly. The results show that the matrix crystallization can be induced by slow cooling from the sintering temperature.

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X-Ray Diffraction Patterns and Acid Consuming Capacity of Aluminum Hydroxide Gel. (수산화알루미늄.겔의 X선회절상과 제산도)

  • 조문혜
    • YAKHAK HOEJI
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    • v.8 no.2
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    • pp.37-44
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    • 1964
  • The relationships involving acid-consuming capacity and X-ray powder diffraction patterns of aluminum hydroxide gel were studied. The aging of antacid efficacy of aluminum hydroxide gel has also been characterized by using X-ray powder diffraction. The acid-consuming capacity decreased with progress of crystallization from amorphous alumino gel, and it was found that aged product at 80.deg. C had crystal structure of bohmite (.alpha.-Al.sub 2/O$_{2}$(OH)$_{2}$). It was also noted that the rate of aging decreased with decreasing pH of aluminum hydroxide gel.

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Synthesis of Analcime by Treating of Domestic Feldspar (국산 장석으로부터의 Analcime합성)

  • 김면섭
    • Journal of the Korean Ceramic Society
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    • v.14 no.1
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    • pp.7-11
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    • 1977
  • Domestic Anyang feldspar was treated in autoclave with 1N sodium hydroxide solution for 1-6 hrs at 100-20$0^{\circ}C$ By X-ray diffraction patterns and cation exchange capacity, the products were examined. The following concecutive reaction was valid. AlbitelongrightarrowAmorphous aluminosilicatelongrightarrowAnalcime The reaction rate constants, k1 and k2, were 0.20 and 0.15(1/hr) at 20$0^{\circ}C$ respectively. The activiation energy from albite to amorphous aluminosilicate was 10 kcal/mol, and from amorphous aluminosilicate to analcine 13 kcal/mol. The analcime obtained was excellent in cation exchange capacity, amounting to 210meq./100g.

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X-shaped Conjugated Organic Materials for High-mobility Thin Film Transistor

  • Choi, Dong-Hoon;Park, Chan-Eon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.310-311
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    • 2009
  • New X-shaped crystalline molecules have been synthesized through various coupling reactions and their electronic properties were investigated. They exhibit good solubility in common organic solvents and good self-film forming properties. They are intrinsically crystalline as they exhibit well-defined X-ray diffraction patterns from uniform and preferred orientations of molecules. They also exhibited high field effect mobilities in thin film transistor (TFT) and good device performances.

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Microstructure and Piezoelectric Properties of Low Temperature Sintering PMW-PNN-PZT-BF Ceramics According to PNN Substitution (PNN 치환에 따른 PMW-PNN-PZT-BF 세라믹스의 미세구조와 압전 특성)

  • Sin, Sang-Hoon;Yoo, Ju-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.2
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    • pp.90-94
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    • 2016
  • In this work, [$Pb(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_x(Zr_{0.5}Ti_{0.5})_{0.97-x}O_3-BiFeO_3$] (x=0.02 to 0.12) composition ceramics were fabricated by the conventional soild state reaction method and their microstructure and piezoelectric properties were investigated according to PNN substitution. The addition of small amount of $BiFeO_3$, $Li_2CO_3$, and $CaCO_3$ were used in order to decrease the sintering temperature of the ceramics. The XRD (x-ray diffraction patterns) of all ceramics exhibited a perovskite structure. The sinterability of PMW-PNN-PZT-BF ceramics was remarkably improved using liquid phase sintering of $CaCO_3$, $Li_2CO_3$. However, it was identified from of the X-ray diffraction patterns that the secondary phase formed in grain boundaries decreased the piezoelectric properties. According to the substitution of PNN, the crystal structure of ceramics is transformed gradually from a tetragonal to rhombohedral phase. The x=0.10 mol PNN-substituted PMW-PNN-PZT-BF ceramics sintered at $920^{\circ}C$ showed the optimum values of piezoelectric constant($d_{33}$), piezoelectric figure of merit($d_{33{\cdot}}g_{33}$), planar piezoelectric coupling coefficient($k_p$) and density : $d_{33}=566$ [pC/N], $g_{33}=29.28[10^{-3}mV/N]$, $d_{33{\cdot}}g_{33}=16.57[pm^2/N]$, $k_p=0.61$, density=7.82 [$g/cm^3$], suitable for duplex ultrasonic sensor application.