• 청정기술
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• 제21권1호
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• pp.39-44
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• 2015

본 연구에서는 다섯 종의 씨앗(춘채, 아욱, 양배추, 배추, 당근)을 이용하여 금속산화물 나노입자(CuO, NiO, Fe₂O₃, Co₃O₄, TiO₂, ZnO)들이 씨앗발아와 발아지수에 미치는 영향을 조사하였다. CuO, ZnO, NiO 나노입자는 씨앗 활성에 뚜렷한 독성 영향을 나타내었으며, 나노입자종류에 따라 상이한 민감도를 나타내었다. 각 나노입자에 대한 독성순서(EC₅₀ 범위)는 다음과 같다: CuO 6~27 mg/L > ZnO 16~86 mg/L > NiO 48~112 mg/L. 나머지 조사 대상 나노입자인 Co₃O₄, TiO₂, Fe₂O₃은 최대 1,000 mg/L 높은 농도 노출에도 뚜렷한 영향을 나타내지 않았다. 씨앗별 상이한 민감도를 나타내었으며, 가장 민감한 종인 아욱의 씨앗발아 EC₅₀은 CuO 5.5 mg/L ZnO 16.4 mg/L, NiO 53.4 mg/L로 조사되었다. 씨앗별 나노입자에 대한 독성 영향은 CuO > ZnO > NiO > Fe₂O₃ ≈ Co₃O₄ ≈ TiO₂ 나타났으나, 당근씨앗은 NiO [EC₅₀ 80.4(71.41~90.54) mg/L]와 ZnO [EC₅₀ 85.8(69.31~106.29) mg/L]가 유사한 독성을 나타내었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.46.2-46.2
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• 2010

최근 수송기기 및 전자부품산업에서의 성능향상 요구에 따라 경량고강도 비철금속재료의 수요가 증대되고 있다. 특히, 세계적으로 에너지 절약 및 환경 공해 규제가 대폭 강화됨에 따라 자동차, 항공기 등 수송기기의 소재경량화 소재로 낮은 밀도 기계적 가공성이 우수한 마그네슘 합금이 각광을 받고 있다. 그러나 Mg합금은 알루미늄 합금과는 달리 보호성 산화피막이 형성되지 않아 내식성 및 고온강도가 매우 취약하다. 이를 보안하기 위해서 본 연구에서는 마그네슘의 강도 개선을 위한 원소로써 고용강화 원소로 많이 쓰이는 Zn과 입자 미세화로 인한 항복강도를 증가시키는 Mn의 3원계 합금에 고온에서 안정한 Mg2Sn상이 형성되는 Sn을 첨가하여 시효처리에 따른 기계적 특성과 미세조직을 관찰하였다. 실험 이전에 Pandat Program에 의한 열역학적 분석을 바탕으로 Mg-Zn-Mn 및 Mg-Zn-Mn-Sn의 상태도 계산 및 MgZn와 Mg2Sn 석출분율을 예측하였다. 열역학 계산을 통해 도출된 석출온도를 통해 Mg-Zn-Mn 및 Mg-Zn-Mn-Sn 합금의 열처리에 따른 경도 및 미세구조를 관찰하였다. 또한, 기계적 특성을 평가하기 위해 상온 및 고온 인장시험을 실시하였고 XRD, SEM을 이용하여 석출상을 분석하였다.

• 한국재료학회지
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• 제4권8호
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• pp.847-854
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• 1994

Mg-Zn-Ce계 합금에서 비정질 단상 및 hcp-Mg입자분산형 비정질합금이 20-40%, Zn, 0-10%Ce과 5-20%Zn, 0-5%Ce 의 조성범위에서 각각 생성되었다. 초미세 hcp-Mg입자분산형 $Mg_{85}Zn_{12}Ce_{3}$비정질합금은 급속응고 또는 급속응고리본의 열처리에 의해 Mg입자의 입경을 4-20nm의 범위로 조절할 수 있었으며, 이 범위에서는 밀착굽힘이 가능할 만큼 충분한 인성을 가지고 있었다. 이 합금의 최대인장강도($\sigma_{B}$)와 파단 연신율($\varepsilon_{f}$)은 hcp-Mg입자의 체적분율에 따라서 670-930MPa, 5.2-2.0%의 범위였으며, 최대 비강도($\sigma_{B}$밀도 =$\sigma_{s}$)는 $3.6 \times 10^5N \cdot m/kg$에 달하였다. 이와 같이 Mg입자분산형 비정질 합금의($\sigma_{B}$), ($\sigma_{s}$)그리고 $\varepsilon_{f}$의 최대치가 Mg-Zn-Ce계 비정질합금(690MPa, $2.5 \times 10^5N \cdot m/kg$, 2.5%)보다 월등하게 높다는 것은 주목할 만 하다. 복합상 조직이 형성됨으로서 기계적 강도가 증가하는 것은 동일 조성의 비정질상보다 강한 hcp과포화 고용체의 분산강화에 기인하는 것이라고 고찰되었다.

• 센서학회지
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• 제14권5호
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• pp.362-367
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• 2005

ZnO films were deposited on MgO substrates (ZnO/MgO) by ultrasonic spray pyrolysis. Substrate temperature varied from $250^{\circ}C$ to $350^{\circ}C$. The crystallographic properties and surface morphologies of the ZnO/MgO films were studied by X-ray diffraction and scanning electron microscopy. The properties of photoluminescence (PL) for the films were investigated by dependence of PL spectra on the substrate temperature and the annealing temperature. The ZnO/MgO films prepared at $350^{\circ}C$ showed the strongest Ultraviolet light emission peak at 18 K and 300 K among the films in this study. The annealing process increases the visible light emission, which is due to the increased oxygen vacancies.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.38-38
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• 2014

SPCC강판상에 PVD 스퍼터링법으로 Zn계 박막을 제작하였고, Zn계 박막의 결정구조와 표면특성에 미치는 산소의 영향을 해석하였다. 실험결과, 진공쳄버 내부에 있는 대부분의 Zn 이온중에서 Mg 이온이 증가할 때, Mg의 증발 및 흡착으로 인한 Zn의 증착핵 성장 억제와 Zn-Mg 금속간 화합물의 분산분포는 Zn-Mg막의 결정입자의 크기를 작게 만들었다. 산소가 쳄버내부에 존해하는 경우에는 XRD 피크는 상대적으로 감소되면서 브로딩하게 나타났다. 또한, 표면특성인 몰포로지의 경향을 분석해 보면 결정입도는 작아지는 현상을 보였다. 이것은 챔버 내부에 존재하는 잔류가스인 산소가 Zn 및 Mg과 같은 증착입자와 결합 및 흡착이 이루어지고, Zn 및 Mg 등이 증착핵의 마이그레이션 효과를 감소시켜 결정입도의 크기가 감소되는 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.151-152
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• 2005

ZnO films were deposited on MgO substrates (ZnO/MgO) by ultrasonic spray pyrolysis. Substrate temperature varied from $250^{\circ}C$ to $350^{\circ}C$. The crystallographic properties and surface morphologies of the ZnO/MgO films were studied by X ray diffraction and scanning electron microscopy. The properties of photoluminescence (PL) for the films were investigated by dependence of PL spectra on the substrate temperature and the annealing temperature. The ZnO/MgO films prepared at $350^{\circ}C$ showed the strongest UV emission peak at 18 K and 300 K among the films in this study.

• 동력기계공학회지
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• 제10권3호
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• pp.45-50
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• 2006

In this paper, creep tests of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy casted by mold under the temperature range of 473.00-573.00K, and the stress range of 23.42-87.00Mpa were done with the equipment of automatic controlled temperature and computer for data acquisition. The activation energies were obtained by relationship between creep rate and temperature, and the stress exponents were obtained by relationship between creep rate and stress. From the experiment results, the activation energies of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloy were 149.87kJ/mol, 147.97kJ/mol, respectively, and the stress exponents of those alloy were 5.13, 5.59, respectively, under the temperature of 473.00-493.00K and the stress range of 62.43-78.00Mpa. And the activation energies of those alloy were 134.41kJ/mol, 129.22kJ/mol, respectively, and the stress exponent of those alloy were 3.48, 3.77, respectively, under the temperature of 553-573Mpa and the stress range of 23.42-39.00Mpa. Also the lifes of Mg-Zn-Mn-Ca alloy were higher than those of Mg-Zn-Mn alloy, and the results of SEM showed fracture surfaces under low temperature had smaller dimples than those under high temperature.

• 한국재료학회지
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• 제13권6호
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• pp.365-368
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• 2003

Small amounts of additives such as mol % 0.13 NiO and mol % 0.01 $CaCO_3$were added to Cu-Zn-Mg ferrites. Basic composition of the Cu-Zn-Mg ferrites was $Cu_{Cu}$X/$Fe_{0.054}$ /$Zn_{0.486}$$Mg_{0.407}$ $Fe_{1.946}$ $O_4$(group A) and $Cu_{0.263}$$Fe_{0.027}$ $Zn_{0.503}$ $Mg_{0.262}$ $Fe_{1.973}$ $O_4$(group B). Specimens were sintered at different temperatures (1010, 1030, $1050^{\circ}C$) for 2 hours in air followed by an air cooling. Then, effects of various composition and sintering temperatures on the microstructure and the magnetic properties such as inductions, coercive forces, and initial permeabilities of the Cu-Zn-Mg ferrites were investigated. The average grain size increased with the increase of sintering temperature. The magnetic properties obtained from the aforementioned Cu-Zn-Mg ferrite specimens were 1,724 gauss for the maximum induction, 1.0 oersted for the coercive force, and 802 for the initial permeability. These magnetic properties indicated that the specimens could be utilized as the core of IFT (intermediate frequency transformer) and antenna in the amplitude modulation.

• 한국주조공학회지
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• 제29권5호
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• pp.213-219
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• 2009

Optimum conditions for production of semi-solid Al-Zn-Mg alloy billets was carried out by the Taguchi design method. And, Al-Zn-Mg alloy billets contained Sc (free, 0.1 and 0.3 mass %) were fabricated at optimum conditions. Evolution of microstructure in semi-solid state was investigated through various liquid fractions, holding times and holding temperatures. The Al-Zn-Mg alloy billets reheated at $615^{\circ}C$ during 30min are grain growth and it was fractured due to increasing liquid fraction before quenching. And, during reheating up to $600^{\circ}C$, grain growth of Al-Zn-Mg alloy billets contained Sc (0.1 and 0.3 mass %) was not occurred in comparison with those of Al-Zn-Mg alloy without Sc. It was thought that $Al_3Sc$ phases have a pinning effect in grain boundary and Sc content of 0.1 mass% is able to inhibit grain growth effectively through reheating process.

• Asian-Australasian Journal of Animal Sciences
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• 제31권8호
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• pp.1267-1274
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• 2018

Objective: The objective of the study was to investigate the effects of zinc amino acid complex (ZnAA) on growth performance, hematological and biochemical parameters in weanling pigs. Methods: In Exp. 1, a total of 216 Duroc${\times}$Landrace${\times}$Large White weanling pigs were assigned randomly to 6 dietary treatments. Each treatment had 6 replicates (pens) with 6 pigs each. The diets were corn-soybean meal based with supplementation of 0, 20, 40, 80, 120 mg Zn/kg from ZnAA or 40 mg Zn/kg from feed-grade zinc sulfate. The experiment lasted 42 days. In Exp. 2, a total of 180 weanling pigs were assigned randomly to 3 dietary treatments supplemented with 0, 80, or 800 mg Zn/kg from ZnAA. Results: In Exp. 1, pigs fed 40 to 80 mg Zn/kg from ZnAA had higher (p<0.05) average daily gain (ADG) than the unsupplemented group during d 0 to 14. During d 0 to 42, the pigs fed 20 to 120 mg Zn/kg from ZnAA had increased (p<0.05) ADG. Pigs fed 20 to 120 mg/kg Zn from ZnAA had lower feed:gain (p<0.05), increased the activity of serum Cu-Zn superoxide dismutase on d 14, and increased serum Zn levels on d 42 (p<0.05). In Exp. 2, pigs fed diets with 800 mg Zn/kg had increased average daily feed intake during d 15 to 28 (p<0.05) compared to the unsupplemented group. During d 0 to 28, the pigs fed supplemental Zn had increased ADG (p<0.05). On d 14 and d 28, pigs fed supplemental Zn had higher the serum alkaline phosphatase activities (p<0.05). No significant differences were observed in the hematological parameters and organ indices. Conclusion: Supplementation with 20 to 80 mg/kg Zn from ZnAA improved the growth performance in weaned pigs. The piglets can tolerate up to 800 mg/kg Zn from ZnAA with limited potential health effects.