• Journal of the Korean institute of surface engineering
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• v.39 no.5
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• pp.206-209
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• 2006

Indium tin oxide (ITO) films were synthesized on polymer (PES, polyethersulfone) at room temperature by pulsed DC magnetron sputtering. By the control of introducing hydrogen to argon atmosphere, the resistivity of ITO films was obtained at $5.27\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$ without substrate heating in comparison with $2.65\;{\times}\;10{-3}\;{\Omega}{\cdot}cm$ under hydrogen free condition. ITO film synthesized at Ar condition was changed from amorphous to crystalline. These result from the enhancement of electron temperature in $Ar\;+\;H_2$ plasma, which induces the increase of ionization of target materials and argon. The dominant increase of ions such as In II and O II and neutral Sn I was monitored by optical emission spectroscopy (OES). Thermal energy required for the crystalline film formation is compensated by kinetic energy transfer through ion bombardments to substrate.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.411-419
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• 1996

The Janggun magnetite deposits occur as the lens-shaped magnesian skarn, magnetite and base-metal sulfide orebodies developed in the Cambrian Janggun Limestone Formation. The K-Ar age of alteration sericite indicates that the mineralization took place during late Cretaceous age (107 to 70 Ma). The ore deposition is divided into two stages as a early skarn and late hydrothermal stage. Mineralogy of skara stage (107 Ma) consists of iron oxide, base-metal sulfides, Mg-Fe carbonates and some Mg- and Ca-skarn minerals, and those of the hydrothermal stage (70 Ma) is deposited base-metal sulfides, some Sb- and Sn-sulfosalts, and native bismuth. Based on mineral assemblages, chemical compositions and thermodynamic considerations, the formation temperature, $-logfs_2$, $-logfo_2$ and pH of ore fluids progressively decreased and/or increased with time from skarn stage (433 to $345^{\circ}C$, 8.8 to 9.9 atm, 29.4 to 31.6 atm, and 6.1 to 7.2) to hydrothermal stage (245 to $315^{\circ}C$, 11.2 to 12.3 atm, 33.6 to 35.4 atm, and 7.3 to 7.8). The ${\delta}^{34}S$ values of sulfides have a wide range between 3.2 to 11.6‰. The calculated ${\delta}^{34}S_{H_2S}$ values of ore fluids are relatively homo-geneous as 2.9 to 5.4‰ (skam stage) and 8.7 to 13.5‰ (hydrothermal stage), which are a deep-seated igneous source of sulfur indicates progressive increasing due to the mixing of oxidized sedimentary sulfur with increasing paragenetic time. The ${\delta}^{13}C$ values of carbonates in ores range from -4.6 to -2.5‰. Oxygen and hydrogen isotope data revealed that the ${\delta}^{38}O_{H_2O}$ and ${\delta}D$ values of ore fluids decreased gradually with time from 14.7 to 1.8‰ and -85 to -73‰ (skarn stage), and from 11.1 to -0.2‰ and -87 to -80‰ (hydrothermal stage), respectively. This indicates that magmatic water was dominant during the early skarn mineralization but was progressively replaced by meteoric water during the later hydrothermal replacement.

• Clean Technology
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• v.26 no.3
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• pp.211-220
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• 2020

This experimental study investigates the design parameters to achieve ultra low NOx combustion of coal using a 80 kW capacity single-burner furnace. The influence of key design parameters such as SN, overall and burner-zone equivalence ratios, primary/secondary air ratio, overfire air (OFA) ratio were tested for a total of 81 cases. The results showed that weak swirl intensity of the burner leads to higher NOx emission whereas strong swirl intensity accompanies increased CO concentration desipte lower NOx emission. Therefore, finding an appropirate swirl intensity is essential for the burner design. Larger flow rate of secondary air increased NOx emission, whereas smaller flow rate stretches the flame and increased CO emission. The lowest NOx emission of 82 ppm (6% O₂) was achieved at the optimal condition of the present burner deisgn. It is expected to furrther lower the NOx emission by introducing splitting the burner secondary air into three or four streams.

• Journal of the Korean Magnetics Society
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• v.7 no.1
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• pp.25-30
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• 1997

Physical and magnetic behaviors of reduced Co-Zn-Ti-Sn substituted Ba-ferrite particles with hydrogen are different from those of reduced-pure Ba-ferrite particles. The coercivity of substituted Ba-feffite particles shows a peaking effect with the reduction temperature ranging from 250 to 520 $^{\circ}C$, while the coercivity of pure Ba-ferrite decreases monotonically. The reduction process of substituted Ba-ferrite has been found to be devided into three steps. At the first and second steps, the magneto-plumbite structure maintained. When the reduced-substituted Ba-ferrite particles are reoxidized, the coercivity is reversible at the first step but irreversible at the second step. During the third step of reduction process above 410 $^{\circ}C$. The magneto plumbite structure was collapsed with formation of $\alpha$-Fe and $BaFeO_{3-x}$ phases and consequently the coercivity distribution is broaden and the coercivity irreversible. The coercivity and saturation magnetization decreases and increases up to 130 emu/g respectively. In this study, it is found that the substituted elements prevent the magneto-plumbite structure from collapse during the reduction process and furthermore migrate from the magnetic sites of $2a+4f_{IV}$, 2b, and 12k to $4f_{VI}$ and 12k'. An increase in the coercivity before the collapse of magneto-plumbite structure is attributed to the migration of cations in hexagonal Ba-ferrite structure.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2410-2412
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• 2011

Using a single step chemical synthesis, we synthesized the potential tumor imaging agent $^{99m}Tc$-diglucose-diethylenetriamine (DGTA) from diethylenetriamine and natural D-glucose. 10 min Incubation of 10 mg of precursor with 50 ${\mu}g$ of $SnCl_2{\cdot}2H_2O$ at room temperature yielded over 95% of $^{99m}Tc$ labeling. The stability for 6 hours in saline or human plasma was over 90%. In vitro tumor cell uptake assays using the SNU-C5 and 9 L cell lines showed that, in 0-400 mg/dL glucose medium, cell uptake of $^{99m}Tc$-DGTA was 1.5-8 times higher than that of [$^{18}F$]FDG. Moreover, [$^{18}F$]FDG uptake was dependent on glucose concentration in the medium, whereas cellular uptake of $^{99m}Tc$-DGTA was not dependent on glucose concentration, suggesting that the two compounds have different uptake mechanisms by tumor cells.

• Korean Journal of Materials Research
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• v.21 no.9
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• pp.491-496
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• 2011

Transparent conducting oxides (TCOs) used in the antireflection layer and current spreading layer of heterojunction solar cells should have excellent optical and electrical properties. Furthermore, TCOs need a high work function over 5.2 eV to prevent the effect of emitter band-bending caused by the difference in work function between emitter and TCOs. Sn-doped $In_2O_3$ (ITO) film is a highly promising material as a TCO due to its excellent optical and electrical properties. However, ITO films have a low work function of about 4.8 eV. This low work function of ITO films leads to deterioration of the conversion efficiency of solar cells. In this work, ITO films with various Zn contents of 0, 6.9, 12.7, 28.8, and 36.6 at.% were fabricated by a co-sputtering method using ITO and AZO targets at room temperature. The optical and electrical properties of Zn-doped ITO thin films were analyzed. Then, silicon heterojunction solar cells with these films were fabricated. The 12.7 at% Zn-doped ITO films show the highest hall mobility of 35.71 $cm^2$/Vsec. With increasing Zn content over 12.7, the hall mobility decreases. Although a small addition of Zn content increased the work function, further addition of Zn content over 12.7 at.% led to decreasing electrical properties because of the decrease in the carrier concentration and hall mobility. Silicon heterojunction solar cells with 12.7 at% Zn-doped ITO thin films showed the highest conversion efficiency of 15.8%.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.43-47
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• 1997

This study was carried out in the laboratory to clarify effects of different temperature of Protopulvinaria mangiferae(Green) on development, survivorship and reproduction. Developmental period of the mango shieldscale from crawlers to preoviposition adult decreased as temperature increased. The threshold temperature andthermal constants for the development of one generation were 11.7"C and 1000.0 day-degrees, respectively. At25$^{\circ}$C and 30$^{\circ}$C, survival rate from egg to preoviposition adult were 82% and 6096, respectively. Hatchability ofeggs was more than 99% at both condition. The reproductive period overaged 50 days(2SnC) and 33 days(30$^{\circ}$C). After mature adult began to reporduce, and more than 50% of the crawlers emerged during the firsthalf of their life time. The net reproduction rate per generation(R), mean length of a generation0 and intrinsicrate of natural increase(r, ) were higher at 25$^{\circ}$C than at 30"C, and the values measured at 25$^{\circ}$C were 132.6, 76.2 and 0.064/female/day, respectively.

• Journal of Animal Science and Technology
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• v.47 no.4
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• pp.655-666
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• 2005

This study was performed to measure physicochemical and textural characteristics, and shelf-life effect of low-fat functional sausages(LFFSs) manufactured with sodium lactate(SL, 3.3%), lac pigment and various molecular weights(MWs) of chitosan (Low=1.5 kDa, Med=30-50 kDa and High=200 kDa) during storage at 15$^{\circ}C$ for 18 days. LFFSs had 73.7-76.0% moisture, lower than 3% fat and 14-15% protein, respectively. pH values were 6.05-6.44 and the control(150 ppm, $NaNO_2$) was the lowest among LFFSs (p<0.05). Increasing storage time decreased pH values, but no differences in pH values were observed up to 6 days of storage (p>0.05). LFFSs containing SL and low MW of chitosan improved water holding capacity (WHC) and different from those with SL and medium-MW chitosan. WHC was decreased with increased storage time and differences of WHC were observed from 18 days of storage. The addition of chitosan reduced both lightness and redness values, as compared to 150 ppm sodium nitrite(SN), and increased storage time decreased yellowness(p<0.05), especially at 12 days of storage. LFFSs with SL and medium-MW chitosan increased most textural properties compared to the control(p<0.05). The addition of SN of 150 ppm in LFFSs retarded microbial growth for E. coli 0157:H7, while those with SL tended to have an antimicrobial effect for Listeria monocytogenes(LM). The growth rate of LM was delayed by addition of various MW of chitosans in LFFSs, especially high MW chitosan, as compared to LFFSs containing SL alone. These results indicated that the functional, textural and antimicrobial effects of LFFSs were improved by addition SL and various MW of chitosan combinations. In addition, 0.05% lac pigment improved the cure color of LFFSs similar to those of 150 ppm SN.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.128-128
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• 2018

최근 디스플레이 기술은 보다 가볍고, 얇고, 선명한 스마트 형태로 발전되고 있다. 특히 스마트산업의 성장으로 터치스크린패널(Touch Screen Panel, TSP)을 사용하는 기술이 다양해짐에 따라 더 높은 감도와 해상도를 달성하기 위한 핵심기술이 필요한 실정이다. TSP는 저항막 방식, 정전용량 방식, 적외선 방식, 초음파 방식 등 다양한 방식이 있다. 그 중 정전용량방식 터치 패널 (Capacitive type touch panel, CTTP)은 다른 유형에 비해 빠른 반응속도 및 멀티 터치 기능 등의 이점을 가지고 있기 때문에 연구의 초점이 되고 있다. 이를 실현하기 위해서 CTTP은 가시광영역의 높은 투과율과 낮은 비저항을 필요로 하기 때문에 박막의 초 슬림화 및 고 결정화도가 선행되어야만 한다. CTTP에 사용되는 투명전극 소재 중에서 40%의 비중을 차지하고 있는 ITO박막은 내구성과 시인성이 좋으나 생산 비용이 비싸다는 단점이 있다. 한편, 반응성 스퍼터링은 기존에 단일 소결체를 사용한 DC마그네트론 스퍼터링법보다 높은 증착률과 낮은 생산 비용으로 초박막을 만들 수 있다는 장점을 가진다. 본 실험에서는 In/Sn (2wt%) 금속 합금 타깃을 사용한 반응성 스퍼터링법을 이용하여 기판 온도 (RT 및 $140^{\circ}C$)에서 두께 30 nm의 In-Sn-O (ITO)박막을 증착하고, 대기 중 $140^{\circ}C$ 온도에서 시간에 따라 열처리한 후 박막의 물성을 관찰하였다. 증착 중 기판 가열을 하지 않은 ITO 박막의 경우, 열처리 시간이 증가함에 따라 비저항은 감소하였고, 홀 이동도는 현저하게 증가하였으며 캐리어 밀도에서는 별다른 차이가 없었다. 이를 통해 비저항의 감소는 캐리어 농도보다는 결정화를 통한 이동도의 증가와 관련 있다는 것을 확인할 수 있었다. 열처리 시간에 따른 박막의 핵 생성 및 결정 성장은 투과 전자 현미경(TEM)으로 명확하게 확인하였으며, 완전 결정화 된 박막의 grain size는 300~500 nm로 확인되었다. 기판온도 $140^{\circ}C$에서 증착한 박막의 경우, 후 열처리를 하지 않은 상태에서도 이미 결정화 된 것을 확인할 수 있었으며, 후 열처리 시에도 grain size에는 큰 변화가 없었다. 이는 증착 중에 박막의 결정화가 이미 완결된 것으로 판단된다. 또한, RT에서 증착한 박막의 경우에는 후 열처리 초기에는 산소공공등과 같은 결함들의 농도가 감소하여 투과율이 증가하였으나 완전한 결정화가 일어난 후에는 투과율이 약간 감소한 것을 확인할 수 있었다. 이는 결정화 시 박막의 표면 조도가 증가하였고 이로 인해 빛의 산란이 증가하여 투과율이 감소한 것으로 판단된다. 이러한 결과로 반응성 스퍼터링 공정으로 제조한 ITO 초박막은 후열처리에 의한 완전한 결정화를 이룰 수 있으며, 이를 통해 얻은 낮은 비저항과 높은 투과율은 고품질 TSP에 적용될 가능성을 가진다고 판단된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.571-571
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• 2013

본 연구에서는 유연 유기태양전지용 플렉시블 InZnSnO (IZTO)/PEDOT:PSS 투명전극을 제작하고 그 특성을 연구하였다. 이를 위해 선형 대향 타겟 스퍼터(Linear Facing Target Sputtering: LFTS) 시스템을 이용하여 그라비아 프린팅된 PEDOT:PSS/PET 매우 얇은 IZTO 투명전극을 성막하였다. 일반적으로 PEDOT:PSS 전극은 수분/산소에 약하지만 매우 얇은 IZTO passivation 층을 코팅함으로써 PEDOT:PSS의 안정성을 향상시키는 동시에 전기적 특성을 향상시킬 수 있다. 이러한 PEDOT:PSS 기반 하이브리드 투명 전극을 제작하기 위해 IZTO 두께를 5 nm에서 40 nm 까지 조절하여 IZTO/PEDOT:PSS 다층 투명전극을 제작하였으며, 이때 IZTO 두께 변수에 따라 제작된 하이브리드 IZTO/PEDOT:PSS 투명전극의 전기적, 광학적 특성을 분석하였다. 최적화된 20 nm의 IZTO의 두께에서 IZTO/PEDOT:PSS 하이브리드 투명전극은 PEDOT:PSS 단일층으로 제작된 플렉서블 투명전극과 동일한 우수한 유연성을 가짐과 동시에 PEDOT:PSS 단일층보다 현저히 낮은 면저항 값(353.6 ohm/sq.)과 높은 광투과율(83.09%)을 나타내었다. 최적화된 IZTO/PEDOT:PSS 투명전극으로부터 제작된 플렉서블 유기태양전지는 IZTO의 passivation 특성으로 인해 PEDOT:PSS 단일막을 이용하여 제작된 플렉시블 투명전극보다 우수한 소자효율을(FF: 59.04%, Voc: 0.588 V, Jsc: 7.554 mA/cm2, PCE: 2.622%) 나타내었다. 이러한 결과들은 LFTS 공법으로 PEDOT:PSS위에 성막된 IZTO passivation 층이 PEDOT:PSS의 특성을 향상시킬 뿐만 아니라, PEDOT:PSS의 안정성도 향상시킬 수 있기 때문에 기존 PEDOT:PSS 기반 투명 전극의 문제점을 해결할 수 있는 해결책으로 적용이 가능하다.