• Animal Bioscience
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• v.34 no.4
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• pp.701-713
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• 2021

Objective: The present work was undertaken to evaluate the effects of storage time, choline chloride, and high concentrations of Cu and Zn on the kinetic behavior of vitamin degradation during storage in two vitamin premixes and four vitamin-trace mineral (VTM) premixes. Methods: Two vitamin premixes (with or without 160,000 mg/kg of choline) were stored at 25℃ and 60% humidity. Besides, four VTM premixes were used to evaluate the effects of choline (0 vs 40,000 mg/kg) and trace minerals (low CuSO4+ZnO vs high CuSO4+ZnO) on vitamin stability in VTM premixes stored in room, and the VTM premixes were stored in room temperature at 22℃. Subsamples from each vitamin and VTM premix were collected at 0, 1, 2, 3, 6, and 12 months. The retention of vitamin A (VA), vitamin D3 (VD3), vitamin E (VE), vitamin K3 (VK3), vitamin B1 (VB1), vitamin B2 (VB2), vitamin B3 (VB3), vitamin B5 (VB5), and vitamin B6 (VB6) in vitamin premixes and VTM premixes during storage was determined. The stability of vitamins in vitamin premixes and VTM premixes was determined and reported as the residual vitamin activity (% of initial) at each sampling point. Results: The effect of choline on VK3 retention was significant in vitamin premixes (p<0.05). The negative effect of storage time was significant for the retentions of VD3, VK3, VB1, VB2, VB5, and VB6 in vitamin premix (p<0.05). For VTM premixes, negative effect of storage time was significant (p<0.05) for the losses of vitamin in VTM premixes. Choline and high concentrations of Cu and Zn significantly increased VA, VK3, VB1, and VB2 loss during storage (p<0.05). The supplementation of high concentrations of Cu and Zn significantly decreased the concentrations of VD3 and VB6 (p<0.05) in VTM premixes at extended storage time. Conclusion: The maximum vitamin stability was detected in vitamin and VTM premixes containing no choline or excess Cu and Zn. The results indicated that extended storage time increased degradation of vitamin in vitamin or VTM premixes. These results may provide useful information for vitamin and VTM premixes to improve the knowledge of vitamin in terms of its stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.205-205
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• 2008

PZT 세라믹은 우수한 유전 및 압전특성을 갖고 있어 변압기, 센서 및 엑츄에이터 등에 널리 응용되고 있다. 그러나, 우수한 특성에도 불구하고 PZT세라믹스의 소결시 PbO의 높은 유독성 및 휘발로 인하여 환경오염을 야기 시킨다. 그러므로 PbO로 구성된 세라믹을 대체하기 위한 우수한 압전특성을 가진 비납계 세라믹스 개발이 연구의 주류를 이루고 있다. 그 중 비납계 NKN와 BZT는 대체물질로 많이 관심을 받고 있다. 이는 일반적인 NKN조성은 우수한 압전성과 높은 큐리온도를 가지고 있을 뿐만 아니라, BZT조성의 Zr성분이 큐리온도를 낮추거나 유전특성을 졸게 하여 유전율 곡선을 완화하게 하는 특징이 있다. 하지만 NKN은 $1140^{\circ}C$이상의 소결온도에서 K의 휘발특성으로 인해 소성 후에도 주변의 수분을 흡수하는 조해성이 발생하는 문제가 발생한다. 그래서 본 연구에서는 낮은 온도에서 NKN계 세라믹스의 밀도를 증가시킬 뿐만 아니라, 우수한 유전 및 압전특성을 갖는 세라믹스를 제조하고자 비납계 $0.94(K_{0.5}Na_{0.5})NbO_3-0.06Ba(Zr_{0.05}Ti_{0.95})O_3$ (NKN-BZT)의 조성을 사용하였고 소결조제로는 $MnO_2$, NiO, $Bi_2O_3$, ZnO, $Li_2CO_3$, CuO등을 변화주어 유전 및 압전 특성을 알아보았다.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.481-492
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• 2005

The purpose of this study is to determine geochemical characteristics for stream sediments in the Gwangju area. We collect the stream sediments samples by wet sieving along the primary channels and dry these samples slowly in the laboratory and grind to under 200mesh using an alumina mortar fur chemical analysis. Major elements, trace and rare earth elements are determined by XRF, ICP-AES and NAA analysis methods. For geochemical characteristics on geological groups of stream sediments, we separate geologic groups which are derived from Precambrian granite gneiss area, Jurassic granite area and Cretaceous Hwasun andesite area. Contents range of major elements for stream sediments in the Gwangju area are $SiO_2\;51.89\~70.63\;wt.\%,\;Al_2O-3\;12.91\~21.95\;wt.\%,\;Fe_2O_3\;3.22\~9.89\;wt.\%,\;K_2O\;1.85\~4.49\;wt.\%,\;MgO\;0.68\~2.90\;wt.\%,\;Na_2O\;0.48\~2.34\;wt.\%,\;CaO\;0.42\~6.72\;wt.\%,\;TiO_2\;0.53\~l.32\;wt.\%,\;P_2O_5\;0.06\~0.51\;wt.\%\;and\;MnO\;0.05\~0.69\;wt.\%.$ According to the AMF diagram for stream sediments and rocks, the stream sediments are plotted on boundary of tholeiitic series and calk alkaline series, which shows that contents of $Fe_2O_3$ are higher in stream sediments than rocks. According to variation diagram of $SiO_2$ versus $(K_2O+Na_2O),$ stream sediments are plotted on subalkaline series. Contents range of trace and rare earth elements for stream sediments in the Gwangiu area are Ba$590\~2170$ppm, Be1\~2.4$ppm, Cu$13\~79$ppm, Nb$20\~34$ppm, Ni$10\~50$ppm, Pb$17\~30$ppm, Sr$70\~1025$ ppm, V$42\~135$ppm, Zr$45\~171$ppm, Li$19\~77$ppm, Co$4.3\~19.3$ppm, Cr$28\~131$ppm, Cs$3.1\~17.6$ppm, Hf$5\~27.6$ppm, Rb$388\~202$ppm, Sb$0.2\~l.2$ ppm, Sc$6.4\~17$ppm, Zn$47\~389$ppm, Pa$8.8\~68.8$ppm, Ce$62\~272$ppm, Eu$1\~2.7$ppm and Yb$0.9\~6$ppm.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.329-342
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• 2006

The purpose of this study is to determine the geochemical characteristics for the stream sediments in the Konyang area. So we can estimate the environment contamination and understand geochemical disaster. We collect the stream sediments samples by wet sieving along the primary channels and slowly dry the collected samples in the laboratory and grind to pass a 200mesh using an alumina mortar and pestle for chemical analysis. Mineralogy, major, trace and rare earth elements are determined by XRD, XRE, ICP-AES and NAA analysis methods. For geochemical characteristics on the geological groups of stream sediments, the studied area was grouped into quartz porphyry area, sedimentary rock area, anorthosite area and gneiss area. Contents of major elements for the stream sediments in the Konyang area were $SiO_2\;41.86{\sim}76.74\;wt.%,\;Al_{2}O_{3}\;9.92{\sim}30.00\;wt.%,\;Fe_{2}O_{3}\;2.74{\sim}12.68\;wt.%,\;CaO\;0.22{\sim}3.31\;wt.%,\;MgO\;0.34{\sim}3.97\;wt.%,\;K_{2}O\;0.75{\sim}0.93\;wt.%,\;Na_{2}O\;0.25{\sim}1.92\;wt.%,\;TiO_{2}\;0.40{\sim}3.00\;wt.%,\;MnO\;0.03{\sim}0.21\;wt.%,\;P_{2}O_{5}\;0.05{\sim}0.38\;wt.%$. The contents of trace and rare earth elements for the stream sediments were $Cu\;7{\sim}102\;ppm,\;Pb\;15{\sim}47\;ppm,\;Sr\;48{\sim}513\;ppm,\;V\;29{\sim}129\;ppm,\;Zr\;31{\sim}217\;ppm,\;Li\;14{\sim}94\;ppm,\;Co\;5.6{\sim}32.1\;ppm,\;Cr\;23{\sim}259\;ppm,\;Cs\;1.7{\sim}8.7\;ppm,\;Hf\;2.1{\sim}109.0\;ppm,\;Rb\;34{\sim}247\;ppm,\;Sc\;4.5{\sim}21.9\;ppm,\;Zn\;24{\sim}609\;ppm,\;Sb\;0.8{\sim}2.6\;ppm,\;Th\;3{\sim}213\;ppm,\;Ce\;22{\sim}1000\;ppm,\;Eu\;0.7{\sim}5.3\;ppm,\;Yb\;0.6{\sim}6.4\;ppm$. Generally, the contents of $Al_{2}O_{3}\;and\;SiO_2$ had a good relationships with each other in rocks but it had a bad relationships in stream sediments for this study area. The contents of $Fe_{2}O_3$, CaO, MnO and $P_{2}O_{5}$ had a good relationships with major and minor elements in stream sediments of this study area. The contents of Co and V in the stream sediments had a good relationships with other toxic elements.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.37-49
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• 1996

The objectives of this study are to investigate the groundwater and surface water contamination, to interpret the attenuation mechanism of contaminant transport, and to find the appropriate contamination indicator. at the two big landfill sites : Nanjido Landfill and Hwasung Landfill. Leachate from the Nanjido, th, Hwasung and the Kimpo waste disposal sites is characterized by high temperature (31.7-40.1$^{\circ}C$), high electric conductivity (14,650-32,800 ${\mu}$S/cm), somewhat higher pH(7.58-8.45) and low Eh (-119.4-20.4 mV), and is enriched in both major (Na$^{＋}$, K$^{＋}$, Ca$^{2＋}$, Mg$^{2＋}$, HC $O_3$$^{－}$, Cl$^{－}$) and minor (Mn, Sr$^{2＋}$, Ba$^{2＋}$, Li$^{＋}$, F$^{－}$, Br$^{－}$) ions. Municipal solid waste leachate and industrial waste leachate are effectively discriminated by the content of S $O_4$$^{2－}$, Fe, and heavy metals. The attenuation mechanism of each component was assessed using the chemical analysis. Cl-normalizing process, WATEQ4F simulation, and preceding flownet analysis. Based on the calculation of Contamination Factor, K, Na, Ca, Mg, B, Zn, HC $O_3$, Cl, F, Br and TOC are effective contamination indicators in the Nanjido landfill site, and K, Na, Ca, Mg, B, S $O_4$, HC $O_3$, Cl, F, Br and TOC in the Habsburg landfill site Particularly, TOC is the best contamination indicator in landfill sites influenced by sea water.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.133.2-133.2
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• 2010

현재 융융탄산염 연료전지의 공기극으로 다공성의 lithiated NiO를 사용하고 있는데 이 재료의 경우 크게 두 가지의 문제점을 안고 있다. 첫 번째는 Ni이 전해질 내로 용해하는 것이고, 두 번째는 낮은 활성으로 인한 높은 공기극의 분극이다. Ni이 전해질로 용해되는 문제는 Co나 Fe를 코팅하여 공기극 표면에 $Li_x(Ni_yCo_{1-y})1-xO_2$나 $Li_x(Ni_yFe_{1-y})_{1-x}O_2$를 형성시켜 NiO의 전해질 내로 용해되는 것을 억제하는 방법이나 ZnO, MgO, $La_2O_3$ 등의 산화물을 NiO 표면에 코팅하여 전해질과 접촉을 막는 방식으로 해결하는 등 많은 연구가 이루어져 왔다. 하지만 연료극의 비해 상당히 높은 공기극의 분극으로 인해 큰 전압손실이 일어나 용융탄산염 연료전지 성능이 낮아지는 문제의 경우 이를 해결하고자 하는 연구는 상대적으로 많이 진행되지 못한 상태이다. 특히 현재 용융탄산염 연료전지의 장기수명화를 위해 기존의 작동온도인 $650^{\circ}C$ 보다 다소 낮은 온도인 $600{\sim}620^{\circ}C$에서 작동하려는 움직임이 있다. 작동 온도가 내려가면 전해질이 휘발되는 속도가 낮아져 전해질 부족에 따른 운전시간이 줄어드는 문제를 해결할 수 있어 장기 수명화를 위해서는 작동온도를 낮추는 것이 매우 유리하다. 하지만 작동 온도가 내려가면서 양 전극에서 일어나는 전기화학 반응 속도가 느려지기 때문에 각 전극에서의 활성화 분극으로 인한 전압손실은 더욱 커질 수밖에 없다. 특히 연료극의 수소산화반응 속도는 공기극의 산소환원반응에 비해 매우 빠르기 때문에 작동 온도가 내려감에 따라 연료극의 분극이 커지는 것에 비해 공기극의 분극이 급격히 커지게 된다. 따라서 운전온도가 낮아지는 상황에서는 낮은 작동온도에서도 성능감소가 적게 일어나 0.8V 이상 운전(150mA/$cm^2$, 단위전지 기준)이 가능한 공기극의 개발이 매우 필요한 실정이다. 이를 해결하고자 본 연구에서는 고체 산화물 연료전지의 공기극의 재료로 많이 연구되고 있는 혼합전도성 물질의 페로브스카이트 구조의 물질을 기존 NiO 전극에 코팅하여 새로운 공기극을 개발하였다. 페로브스카이트 구조의 물질로 대표적인 LSCF 물질을 사용하였으며 LSCF를 코팅한 공기극을 이용한 단위전지에서 150mA/$cm^2$의 전류를 흘려주었을 때 0.84V의 성능을 1000hr 유지하였다. 이는 기존의 NiO 전극을 사용했을 때보다 15~20mV 높은 값이다. 낮은 작동온도에서도 좋은 성능을 보였는데, 기존의 NiO 전극의 경우 $630^{\circ}C$에서 0.79V의 성능을 보인 반면 LSCF가 코팅된 공기극의 경우 $620^{\circ}C$에서 0.811V의 매우 좋은 성능을 보였다. 이는 LSCF의 산소이온전도성 및 전기전도성이 공기극에서의 분극을 낮추어 성능을 증가시키는 것으로 보인다.

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.675-687
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• 2006

The purpose of this study is to determine the geochemical characteristics of the stream sediments in the Cheongpung area. So that we can understand the natural background and predict the prospects of geochemical disaster, if any. We collected the stream sediments samples by wet sieving along the primary channels and slow dried the collected samples in the laboratory and ground them to pass a 200 mesh using an alumina mortar and pestle for chemical analysis. Miner-alogical characteristics, major, trace and rare earth elements were determined by XRD, XRF, ICP-AES and NAA analysis methods. For geochemical characteristics on the geological group of stream sediments, the studied area was grouped into granitic gneiss area, metatectic gneiss area, Dado tuff area, Yuchi conglomerate area, and Neungju flow area in the Cheongpung area. Contents of major elements for the stream sediments in the Cheongpung area were $SiO_2\;47.31{\sim}72.81\;wt.%,\;A1_2O_3 \;11.26{\sim}21.88\;wt.%,\;Fe_2O_3\;2.83{\sim}8.39\;wt.%,\;CaO\;0.34{\sim}7.54\;wt.%,\;MgO\; 0.55{\sim}3.59\;wt.%,\;K_2O\;1.71{\sim}4.31\;wt.%,\;Na_2O\;0.56{\sim}2.28\;wt.%,\;TiO_2\;0.46{\sim}1.24\;wt.%,\;MnO\;0.04{\sim}0.27\;wt.%,\;P_2O_5\;0.02{\sim}0.45\;wt.%$. The con-tents of trace and rare earth elements for the stream sediments were $Ba\;700ppm{\sim}8990ppm,\;Be\;1.0{\sim}3.50ppm,\;Cu\;6.20{\sim}60ppm,\;Nb\;12{\sim}28ppm,\;Ni\;4.4{\sim}61ppm,\;Pb\;13{\sim}34ppm,\;Sr\;65{\sim}787ppm,\;V\;4{\sim}98ppm,\;Zr\;32{\sim}164ppm,\;Li\;21{\sim}827ppm,\;Co\;3.68{\sim}65ppm,\;Cr\;16.7{\sim}409ppm,\;Cs\;2.72{\sim}37.1ppm,\;Hf\;4.99{\sim}49.2ppm,\;Rb\;71.9{\sim}649ppm,\;Sb\;0.16{\sim}5.03ppm,\;Sc\;4.97{\sim}52ppm,\;Zn\;26.3{\sim}375ppm,\;Ce\;60.6{\sim}373ppm,\;Eu\;0.82{\sim}6ppm,\;Yb\;0.71{\sim}10ppm$.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.07a
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• pp.59-101
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• 2002

PVDF is good material for a hollow fiber membrane with high porosity and excellent hydrophobicity. Asymmetric PVDF hollow fiber membranes were prepared by the Loeb-Sourirajan phase inversion method. Asymmetric PVDF hollow fiber membranes could be controlled in pore size and porosity using various additives(LiCl, ZnCl$_2$) and internal coagulants (water, EtOH/water, and DMAc/water mixture). $CO_2$removal efficiency of asymmetric PVDF hollow fiber membranes was 1.2 times high than that of commercialized PP hollow fiber membranes at MEA 5wt% solution. $CO_2$flux of asymmetric PVDF hollow fiber membranes was 2.5 times higher than that of commercialized PP hollow fiber membranes. $CO_2$removal efficiency and absorption rate of asymmetric PVDF hollow fiber membranes were 30 times higher than those of packed column at absorbent $H_2O$. $CO_2$flux of asymmetric PVDF hollow fiber membranes at MEA 5wt% solution was 48 times higher than that of pure water. In the case of MEA 5wt% solution used as an absorbent, the $CO_2$absorption rate and removal efficiency of PVDF hollow fiber membrane were 2.3 times higher than that of a packed column.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.179-180
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• 2015

• Advances in nano research
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• v.15 no.1
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• pp.67-74
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• 2023

The combination of physical activities and individual skills in sports creates an entertaining and competitive environment governed by a set of rules. In today's world, sports attract significant attention and are approached differently by various groups. Inevitably, injuries occur in sports, significantly impacting an athlete's performance and ability to participate in exercises and competitions. Addressing this issue, one of the crucial measures involves restoring the athlete's ability to engage in sports and compete. Sports rehabilitation serves as a treatment to mitigate the effects of injuries, and when combined with surgery, it can expedite the recovery process. Therefore, the primary objective of this study is to utilize a biocompatible technology for synthesizing zinc oxide (ZnO) nanoparticles in sports rehabilitation, ensuring minimal harm to the environment.