• Metals and materials international
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• 제24권6호
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• pp.1386-1393
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• 2018

The solubility of $TiO_2$ in $NaF-CaF_2-BaF_2$ ternary eutectic melts was investigated at the temperature range of $1025-1150^{\circ}C$. The least-squares equation was obtained from the relationship between the reciprocal temperature and the natural logarithm of the titanium concentration in the melts saturated with $TiO_2$. The corresponding partial molar enthalpy of dissolution of $TiO_2$ was found to be 188 kJ/mol. The titanium saturation concentration was 3.73 wt% at $1100^{\circ}C$. From the titanium concentration change with the added amount of $TiO_2$ at different holding time after a final stirring, it was found that not only complete dissolution of $TiO_2$ but also enough sedimentation of excessive $TiO_2$ should be guaranteed to obtain more reliable solubility data. The holding time of 10 h was found to be enough for the excessive $TiO_2$ particles to settle down in our experimental conditions. It is noteworthy that in case of adding $TiO_2$ in excess of its solubility, the $Ba_{1.12}(Ti_8O_{16})$ phase was observed at the lower and bottom of the solidified salt ingots.

• 한국전기전자재료학회논문지
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• 제11권3호
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• pp.208-213
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• 1998

Microwave dielectric properties of $BiNbO_4$ containing CuO and $V_2O_5$(BN ceramics). BN ceramic with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) was sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. The dielectric constant of 44.3, TCF (Temperature Coefficient of resonance Frequency) of 2 ppm/$^{\circ}$ and Q${\times}f_o$ value (product of Quality value and resonance Frequency) of 22,000GHz could be obtained from those ceramics. It is observed that orthorhombic structure was stable $1000^{\circ}C$. As sintering temperature increases, the dielectric properties decreased. The main reasons were abnormal grain growth and the main peak of triclinic moved from the main peak of orthorhombic.

• 한국세라믹학회지
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• 제37권6호
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• pp.552-558
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• 2000

LiMn2O4 thin fiolm cathodes for Li-ion secondary battery were fabricated by r.f. magnetron sputtering technique. As-deposited films were amorphous. A spinel structure could not be obtained LiMn2O4 films by in-situ thermal annealing. After post thermal annealing over $700^{\circ}C$ in oxygen atmosphere, LiMn2O4 films prepared above 100 W r.f. power could be crystallized into a spinel structure. The electrochemical property of the LiMn2O4 film cathodes was tested in a Li/1 M LiClO4 in PC/LiMn2O4 cell. From cyclic voltammetry at scan rate of 2mV/sec of 2.5~4.5V, LiMn2O4 electrode prepared by post annealing at 75$0^{\circ}C$ showed good initial capacity. LiMn2O4 electrode prepared by post annealing at 80$0^{\circ}C$ showed the best crycling performance.

• 센서학회지
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• 제14권5호
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• pp.297-301
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• 2005

Nanocrystalline SnO and $SnO_{2}$ powder have been prepared by hydrazine method. Sn-Hydrazine complex was formed by the reduction between aqueous $SnCl_{2}$ solution and hydrazine monohydrate. $SnO_{2}$ nano powder was prepared by the decomposition of Sn-Hydrazine complex at $450^{\circ}C$. When NaOH was added to Sn-hydrazine complex, SnO powder with nano-sheet morphology could be prepared. This can be attributed to the role of $OH^{-}$ ion as a reducing agent.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.211.1-211.1
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• 2013

We fabricate the conductive zinc oxide(ZnO) thin film using UV-enhanced atomic layer deposition. ZnO is semiconductor with a wide band gap(3.37eV) and transparent in the visible region. ZnO can be deposited with various method, such as metal organic chemical vapour deposition, magnetron sputtering and pulsed laser ablation deposition. In this experiment, ZnO thin films was deposited by atomic layer deposition using diethylzinc (DEZ) and D.I water as precursors with UV irradiation during water dosing. As a function of UV exposure time, the resistivity of ZnO thin films decreased dramatically. We were able to confirm that UV irradiation is one of the effective way to improve conductivity of ZnO thin film. The resistivity was investigated by 4 point probe. Additionally, we confirm the thin film composition is ZnO by X-ray photoelectron spectroscopy. We anticipate that this UV-enhanced ZnO thin film can be applied to electronics or photonic devices as transparent electrode.

• 대한한의학원전학회지
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• 제13권1호
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• pp.117-145
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• 2000

Tongmu I Je-ma(1837-1900) set up Sasang Constitutional Medicine(四象體質醫學), a medical theory that would be original in the Korean medical history through his book ${\ll}$Tang-uisusebowon(東醫壽世保元)${\gg}$. In this book, he writes that he found the clue to his sasang Constitution(四象體質) theory from ${\ll}$Hwangjenaegyong(黃帝內經)${\gg}$. But the main logic that gives shape to the Constitution(體質) theory is $s{\check{o}}ng-ch{\check{o}}ng$ theory(性情論) of Confucian. Therefore, Tongmu(東武)'s Constitution $s{\check{o}}ng-ch{\check{o}}ng$ theory(體質性情論) is fundamentally based on confucian thoughts. Kongmaeng(孔孟) saw $s{\check{o}}ng$(性) as a base for connecting the entire mankind to be united, and $ch{\check{o}}ng$(情) as a individual thing that can exalted differently according to one's state of mind. Chuja(朱子) weakene the human's active volition by dividing $s{\check{o}}ng$ and $ch{\check{o}}ng$ as ibal(理發) and kibal(氣發) and therefore describing mankind to be submitted to Heaven's will. On the other hand Yolgok(栗谷) generalized $s{\check{o}}ng-ch{\check{o}}ng$ in the active mind of man himself by saying that $s{\check{o}}ng$ is when i-ki(理氣) does not act as a bodily function of the mind and $ch{\check{o}}ng$ is when it does. Furthennore he emphasized man's activeness on pursuing good by saying that the division of good and bad does not start from the origin of motion but is divided by the condition of ki(氣) which leads motion. Tongmu, who was influenced by Yulgok linked both $s{\check{o}}ng$and $ch{\check{o}}ng$ through, happiness, anger, sadness, pleasure(喜怒哀樂), and saw $s{\check{o}}ng$ as the ability to recognize good which is in the kijil(氣質) formed from the integration of i-ki, and saw $ch{\check{o}}ng$ as $s{\check{o}}ng$ blurred by man's greed. In addition to this, he says that the direct connection between each person's divergence in $s{\check{o}}ng-ch{\check{o}}ng$ and the condition of Four-organ(四臟) which is ki, not the mind which is i(理) forms sasangch'ejirin(四象體質人). His theory that illness comes from the partiality of $s{\check{o}}ng-ch{\check{o}}ng$ and therefore can prevent this by clarifying the mind and adjusting $s{\check{o}}ng-ch{\check{o}}ng$ through volition, has led Korean oriental medicine to be human based.

• 한국물환경학회지
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• 제21권6호
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• pp.643-650
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• 2005

In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.

• 교육시설 논문지
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• 제24권5호
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• pp.11-18
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• 2017

An university dorm has significant implications in terms of providing residential, living, and learning spaces. With its supportive function, a dorm enables each university to provide higher level of education. The operation & maintenance(O&M) condition of the dorm has a decisive effect on the students' satisfaction. Accordingly, high levels of O&M services should be performed for students. However, Korean dorms are being operated and maintained by their own O&M guidelines without the consideration of spatial characteristics of dorm facilities and the comprehensive and systematic understanding on effective O&M processes. Given the fact that dorm facility can be a crucial factor in determining the entire quality of university and its O&M condition is closely related to the satisfaction of students, it is imperative that we need to pay more attention to the O&M condition and services. Therefore, the main objective of this research is to improve dorm students' satisfaction levels by applying different O&M method, preventive maintenance rather than reactive maintenance which has been performed so far. In ordering for doing it, 'Facility Management(FM) Standard' from KS, 'Facility Performance Indicator(FPI)' from APPA: Leadership in educational facilities and 'Building O&M Inspection Manual' from Korean Ministry of Land, Infrastructure and Transport were analyzed to come up with 15 significant O&M factors. After extracting O&M factors, the survey was conducted to determine importance rate and performance rate of each O&M factor. Using the Important-Performance Analysis(IPA), the priority of 15 O&M factors was established. The result of this research will be helpful for the efficient dorm facility O&M services and for facility managers to appropriately allocate the limited resources and human power.

• 한국산업정보학회논문지
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• 제22권1호
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• pp.117-126
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• 2017

본 연구는 온 오프라인의 경쟁이 치열한 출판물 유통환경에서 차별화된 서비스 개념으로 운영되고 있는 반디앤루니스 센텀시티점에 대한 사례 연구이다. 반디앤루니스는 국내에 14개의 오프라인 서점과 온라인 서점을 갖고 있는 대형서점 중 하나이다. 본 연구의 목적은 반디앤루니스의 O2O 서비스와 서비스 디자인에 대한 독특한 시례와 관행을 통해서 시사점을 제공하는데 있다. 반디앤루니스의 역사, 서비스 컨셉, 가치, 성과 등을 다양한 매체를 활용해 찾고, O2O서비스와 서비스 디자인에 대한 기존 연구들을 살펴 보았다. 즐거운 고객 경험을 제공하기 위해서는 고객의 관점에서 서비스를 디자인해야 하며, 고객이 오랫동안 머물 수 있도록 고객의 라이프 스타일을 고려한 다양한 서비스를 제공할 수 있어야 한다. 빅데이터, 사물인터넷, 인공지능(AI)의 시대에 온 오프라인의 경계를 허물고 고객 경험을 향상시킬 수 있는 서비스를 제공하기 위해서는 정보 통신기술을 활용한 서비스 디자인 혁신이 필요할 것이다.

• 한국세라믹학회지
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• 제37권7호
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• pp.705-712
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• 2000

In this study, the dispersion stability of CeO2 based complex oxide was studied, and density, porosity, and microstructure of green body were investigated using colloid surface chemistry to manufacture the Gd2O3 doped CeO2 solid electrolyte in an aqueous system. To prepare the stable slurry for slip casting, the dispersion stability was examined as a function of pH using ESA(electrokinetic sonic anplitude) analysis. The dynamic mobility of particles was enhanced with anionic and cationic dispersant were added the amount of 0.5wt% respectively, but pH value in slurries didn't move to below 6.0 because of the influence of dopants. This phenomenon also appeared in the CeO2-Y2O3 and CeO2-Sm2O3 systems, so it could be inferred that rare earth dopants such as Gd2O3, Sm2O3 and Y2O3 not only have the similar motion with changing pH in an aqueous system but also can be dissolved in the range of pH 6.0∼6.5. In CeO2-Gd2O3 system, when the anionic dispersant was added the amount of 0.5wt% and pH value in slurries was fixed at 9.5, the green body density was 4.07g/㎤, and the relative density of sintered body was 95.2%. It could be inferred from XRD analysis that Gd3+ substituted into Ce4+ site because there was no free Gd2O3 peak.