• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.11-20
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• 1999

We have designed and fabricated direct-and gap-coupled microstrip hairpin-comb filters by patterning double-sided YBCO films on a single 50-mm-diameter, 0.5-mm-thick $LaAlO_3$ wafer. Both filters have a center frequency at 1.773 GHz, 12 MHz bandwidth, 0.5 dB minimum insertion loss in the passband, and very strong out-of- band rejection. Due to two attenuation poles below and above the passband, the direct-coupled hairpin-comb filter showed a better skirt characteristic than the gapcoupled hairpin-comb filter which had only one attenuation pole below the passband.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.399-399
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• 2009

CIS계 화합물 태양전지는 높은 광흡수계수와 열적 안정성 및 Ga 조성 조절을 통한 밴드갭 조절이 용이해 고효율 박막 태양전지로 각광 받고 있다. CIS 태양전지의 광 흡수층 제조 방법으로는 여러 가지 방법이 있지만 본 연구에서는 가장 높은 에너지 변환 효율을 달성한 Co-Evaporation 방법을 사용하기로 하였다. 미국의 NREL의 경우 Co-Evaporation 방법을 사용해 20%의 에너지 변환 효율을 달성한 바가 있다. 하지만 이러한 효율의 태양전지는 실험실에서 연구용으로 제작한 아주 작은 면적으로 태양전지 양산화에 그대로 적용하기는 힘들다. 따라서 CIGS 태양전지의 양산화 적용을 위해 대면적화가 필수적이다. 본 연구에서는 기존의 3 stage 방식을 이용해 광흡수층을 증착하여 최적화 조건을 연구하였다. 또한 기판의 면적 증가에 따라 효율과 Voc, Jsc, F.F가 얼마나 감소하는지 실험하여 보았다. 기판은 soda lime glass를 사용 하였으며 후면 전극으로 약$1{\mu}m$ 두께의 Mo를 DC Supptering 방법을 이용해 증착하였다. 다음으로 약 $2{\mu}m$이상의 광흡수층을 Co-Evaporation 방법을 이용하여 증착 하였으며 buffer층으로는 약 50nm의 CdS층을 CBD방법을 이용하여 제조 하였다. TCO층으로 약 50nm의 i-ZnO와 약 450nm의 Al-ZnO를 RF Sputtering 방법을 이용하여 증착 하였다. 마지막으로 앞면 전극으로 약 $3{\mu}m$의 Al을 Thermal Evaporation 방법으로 증착하였다. 태양전지 소자의 면적은 $0.49cm^2$, $25cm^2$, $100cm^2$로 각각 면적을 달리하며 효율을 비교 분석하였다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.283-290
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• 2017

Objectives: This study aimed to evaluate the relationship between filter replacement and filter performance change in particulate filters used in the workplace. Methods: Three types of particulate respirator filters are mainly used in the workplaces. These were tested against the filter performance safety certification standard for dust masks established by the Ministry of Employment and Labor(MoEL). Used filters were collected to test their performance, such as filter pressure drop, efficiency, and quality factors. All these factors were evaluated by a filter tester. To compare filter performance between used and new ones, the same kinds of new filters were also tested together under the same procedures. Results: A total of 270 used filters were collected for testing. The main reasons to replace the filters were difficulty in breathing(46.2%), dirty/odor influx(19.7%), and a combination of factors(26.7%). The pressure drop for two special class groups was significantly different(new filters: $20.72{\pm}3.33mmH_2O$; used filters: $24.70{\pm}5.26mmH_2O$, p<0.0001). In the case of penetration, new filter groups indicated $0.0032{\pm}0.0040%$, while that of the used filters was $0.0596{\pm}0.1187%$. The quality factor for the used filters($0.34{\pm}0.09$) significantly decreased compared to the new filters($0.53{\pm}0.08$) (p<0.0001). Conclusions: Filter performance including pressure drop, penetration, and the quality factor was evaluated and compared between new and used filters in the workplace. The results showed that general filter performance deteriorated more for change of pressure drop, penetration and the quality factor.

• Clinics in Shoulder and Elbow
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• v.8 no.2
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• pp.105-109
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• 2005

Purpose: To Analyze the exit site of pin inserted at the anterior glenoid rim in the reconstruction of the Bankart lesion and SLAP lesion using transglenoid suture technique. Materials and Methods: In the twenty adult right cadeveric scapula, insertions of pin were performed using guide at the position of 1, 2, 3 O'clock of glenoid rim. We measured the exit site of dorsal surface of the scapula by medial distance from sagittal plane of lateral border of scapular spine and the vertical distance from posterior border of the scapular spine. Results: When the pin was inserted caudally within 10 degree, at the position of 1, 2, 3 O'clock, the medial distance from lateral border of the scapula is averaged 29.4, 19.2, 34.0 mm respectively and the vertical distance from posterior border of the scapular spine is averaged 15.0, 18.6, 17.2 mm respectively. When the pin was inserted caudally within 20-30 degree, the medial distance is averaged 14.6, 14.2, 15.8 mm respectively and the vertical distance is averaged 31.6, 31.9, 32.1 mm respectively. Conclusion: When the pin was inserted caudally within ten degrees using the guide, the pin exit appeared at the more medial side of the base of scapular spine and the more inferior of scapular spine. This can make the firm suture tied over scapular spine during repair SLAP and the Bankart lesion, and also prevent the injury of suprascapular nerve.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.314-320
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• 2021

Controlling ambient humid condition through high performance humidity sensors has become important for various fields, including industrial process, food storage, and the preservation of historic remains. Although aerosol deposited humidity sensors using ceramic BaTiO₃ (BT) material have been widely studied because of their longtime stability, there remain critical disadvantages, such as low sensitivity, low linearity, and slow response/recovery time in case of the sensors fabricated at room temperature. To achieve superior humidity sensing properties even at room temperature condition, BT-Cu composite films utilizing aerosol deposition (AD) process have been proposed based on the percolation theory. The BT-Cu composite films showed gradually improved sensing properties until the Cu concentration reached 15 wt% in the composite film. However, the excessive Cu (above 30 wt%) containing BT-Cu composite films showed a rapid decrease of the sensing properties. The results of observed surface morphology of the AD fabricated composite films, to figure out the metal filler effect, showed correlation between surface topography as well as size and the amount of open pores according to the metal filler content. Overall, it is very important not only dielectric constant of the humidity sensing films but also microstructures, because they affect either the variation range of capacitance by ambient humidity or adsorption/desorption of ambient humidity onto/from the humidity sensing films.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.2
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• pp.152-161
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• 2024

In this study, a fuel cell system for future defense unmanned vehicles was designed and validated. A Co/Al₂O₃-Ni foam catalyst for NaBH₄ hydrolysis was characterized using several analytical methods. A NaBH₄ hydrogen generation system with the Co/Al₂O₃-Ni foam catalyst continuously generated hydrogen at elevated reaction temperatures. The fuel cell system with the NaBH₄ hydrogen generation system was designed and tested. The performance of the fuel cell system was comparable to that of the fuel cell system using pure hydrogen. Therefore, the fuel cell system with the NaBH₄ hydrogen generation system is a suitable power source for future defense unmanned vehicles owing to its easy refueling and simple system.

• Membrane Journal
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• v.15 no.2
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• pp.114-120
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• 2005

The purpose of this study is to obtain practical information about membrane coupled $ A_2O$ system for muncipal wastewater treatment. A flat-plate microfiltration (MF) module with a pore size $0.25\;{\mu}m$ was submerged into the aeration basin and treated water was filtrated through the membrane by continuous suction with low pressure. The system was operated with synthetic wastewater to find operational parameters of internal recycle ratio and maximum MLSS showing best water quality and long-term stability. The internal recycle was defined as type 1 for aerobic to anoxic tank and type 2 for anoxic to anaerobic tank, respectively When the flux was maintained at $0.015\;m^3/m^2/hr$ (15 LMH) with 2Q type 1 internal recycle ratio, the optimal operational setting were 10 internal recycle ratio for type 2 and maximum MLSS of 11,000 mg/L among tested conditions. At this condition, removal efficiencies of BOD, CODcr, T-N and T-P showed $97.3\%,\;94.2\%,\;64.0\%,\;63.0\%$, respectively.

• Solar Energy
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• v.20 no.2
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• pp.43-54
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• 2000

We prepared and characterized $Cu(In_{1-x}Ga_x)Se_2$(CIGS) films using a elemental co-evaporation method for absorbing layer of high efficiency thin film solar cells. The CIGS films deposited on a soda-lime glass exhibited low resistivity because of higher carrier concentration. Na was accumulated at the CIGS surface and the 0 and Se were also accumulated at the surface, suggesting that oxidation is a driving force of Na accumulation. The structure of CIGS film was modified or a secondary phase was formed in the Cu-poor CIGS bulk films probably due to the incorporation of Na into Cu vacancy sites. As the Ga/(In+Ga) ratio increased, the diffraction peaks of $Cu(In_{1-x}Ga_x)Se_2$ films were shifted to larger angle and splitted, and the grain size of $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films became smaller. All $Cu_{0.91}(In_{1-x}Ga_x)Se_2$ films showed the p-type conductivity regardless of the Ga/(In+Ga) ratio. Ag/n-ZnO/i-ZnO/CdS/$Cu_{0.91}(In_{0.7}Ga_{0.3})Se_2$/Mo solar cells were fabricated. The currently best efficiency in this study was 14.48% for $0.18cm^2$ area ($V_{oc}=581.5mV,\;J_{sc}=34.88mA$, F.F=0.714).

• Economic and Environmental Geology
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• v.47 no.2
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• pp.181-191
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• 2014

Olon Ovoot gold mine, Mongolia, is located in the Omnogobi province which is south 500 km from Ulaanbaatar. The mine area consists of the Devonian Bot-Uul khudag formation, the Upper Devonian intrusions, and the Upper Devonian or the Early Jurassic quartz veins. The quartz veins contain from 1 to 32 g/t gold with an average of 5 g/t gold. The quartz veins vary from 0.2 m to 25 m and are concordant or discordant with foliation of the green-schist. The mineralogy of the quartz veins is simple and consists of mainly of white massive quartz with partly transparent quartz in cavity. Quartz, sericite, chlorite, pyrite and carbonates(ankerite, dolomite and siderite) were observed in the alteration zone. Carbonate minerals occur as disseminated, coarse or fine grains with quartz, sericite, chlorite and pyrite near vein margin or within wall-rock xenoliths in quartz vein. Ankerite is present as later dark grey ankerite(13.51 to 16.89 wt.% FeO) and early white grey ankerite(16.67 to 19.90 wt.% FeO). The FeO contents of early ankerite are higher than those of later ankerite. Dolomite contains from 3.89 to 10.44 wt.% FeO and from 0.10 to 0.47 wt.% MnO. Dolomite is present as dark grey dolomite(4.06 to 6.87 wt.% FeO), light white grey dolomite(6.74 to 7.58 wt.% FeO) and grey white dolomite(7.33 to 10.44 wt.% FeO). The FeO contents of white grey dolomite are higher than those of dark grey dolomite. Siderite contains from 34.25 to 48.66 wt.% FeO, from 6.79 to 14.38 wt.% MgO, from 0.06 to 0.26 wt.% MnO and from 2.08 to 8.08 wt.% CaO.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.239-246
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• 2008

Yeongweol sericite deposit of Gangwon Province is regarded as one of the sericite deposits derived from granitic rocks due to post-magmatic alkali metasomatism, and the other sericite deposit of the same origin is the Daehyun mine of Gyungbug Province. Sericite ores were originated from leucocratic granitic stocks of Cambrian-Triassic age which intruded the pegmatitic migmatite of the unknown age and granite of the Pre-cambrian age, respectivcly. Jangsan quartzite of the lowermost formations of the Paleozoic era, which played as the capping rock protected from the leakage of the hydrothermal solution. It is well known that those sericite deposits arc formed during formation of the geosyncline, and they are also situated in the margins of the Hambaeg Syncline. Leucocratic granites commonly contain pegmatites with tourmaline crystals, and are rich in potassium feldspars, and sodium plagioclase as well. Sericitized ores are mainly found as we go up to the higher elevations or to the margins of the stocks. And some of the Highest grade sericite ores show the monominerallic character composed of nearly pure sericite probably doc to the ultra greisenization. Chemical analysis shows higher $Na_{2}O$ and $K_{2}O$ contents $(2.00\sim7.03wt%)$ as the sericitizations arc preceded and they represent obvious greisenization. But low CaO contents $(0.05\sim4.51wt%)$ indicate that albitizations are so weak. Pyrophyllite of the Youngweol area is often accompanied by the sericite, indicating rather stronger thermal effect than the Daehyun mine. It is known that there are several Sn deposits originated from greisenization in the Taebaegsan region. And greisens are inclined to contain W, Mo and several REE's such as Be, Nb and Li, and so Taebaegsan region interbedded with lots of carbonate formations are still worthwhile to survey for those metallic deposits.