• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.269-271
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• 2006

Pyromellitic anhydride(PMDA)와 4,4-Oxydianiline(ODA)로부터 Polyimide의 전구체인 Poly(amic acid)(PAA)를 합성하고, 이를 열을 가하여 Polyimide되는 반응을 적외선 분광법을 이용하여 추적하였다. 이미드화 반응은 $175^{\circ}C$에서 1시간, $185^{\circ}C$에서 1시간, $195^{\circ}C$에서 1시간, $215^{\circ}C$에서 1시간, $235^{\circ}C$에서 1시간 경화시킴으로 완결됨을 확인하였다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.126-127
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• 2006

In this study, nano grain W is fabricated by Severe Plastic Deformation-Powder Metallurgy (SPD-PM) process. W powder and W-Re powder mixtures are processed by SPD-PM process, a Mechanical Milling (MM) process. As results, a nano grain structure, whose grain size is approximately 20nm, is obtained in W powder after MM for 360ks. A nano grain W compact, whose grain size 630nm, has excellent deformability above 1273K. A nano grain W-10Re compact is composed of equiaxed grain, a grain growth is restrained and has low dislocation density after the large deformation; therefore it is considered that W-Re compact shows superplasticity.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.854-857
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• 1996

Absorption and luminescence spectra of Eu3+ (aquo) and the two different 1: 3 Eu3+: ligand systems in aqueous solutions are measured under mild acidic pH condition. The oxydiacetate (ODA) and dipicolinate (DPA) ligands, forming the similar geometric complexes, are used in this work. The three intensity parameters, Ωλ (λ=2, 4, and 6) are empirically determined by applying the Judd-Ofelt theorem to the oscillator strengths of the six absorption bands arising from the ground 7F0 state. Among the three intensity parameters, the Ω2 is found to response markedly to a miner change in the ligand environment via the 7F0→5D0 transition. In addition, the relative oscillator strengths of the four luminescence bands in the visible region, assigned to the 5D0→7FJ (J=1, 2, 3 and 4) transitions are obtained to investigate their sensitivity to the ligand environment. Among the four bands, the 610 nm band, attributed to the 5D0→7F2 transition, shows hypersensitivity in the luminescence.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.260-260
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• 2015

에티오피아는 국제원조사업으로 SNNPR주 Gurage zone에 "안전한 식수 공급 사업"을 요청하였다. 이에 KOICA에서는 당해 지역내 국제원조사업 실시에 대한 성과를 평가하고자, ODA 사업 추진 전 지역주민의 "삶의 질"을 사전 평가하였다. 본 논고는 KOICA의 에티오피아 SNNPR주 Gurage zone "삶의 질" 평가 결과이다. "삶의 질" 분석을 위한 평가기준으로는 1. 현지 지역주민의 물이용 현황, 위생 및 환경 현황, 취수활동이 교육에 미치는 영향, 취수활동이 가정 경제 활동에 미치는 영향 등을 분석하고, 2. 식수공급사업 추진 시, 지역주민이 바라는 식수개발사업의 유형을 살펴보았다. 분석을 위한 자료 조사 방법으로는 설문 방법을 선택하였으며, 설문은 물 이용 현황, 질병 및 위생 관리 현황, 취수활동이 교육 및 가계 경제에 미치는 영향 그리고 지역주민이 바라는 식수사업의 방향 및 이유 등을 중심으로 구성하였다. 설문지 유형은 현황 관련 계량적 수치를 답하는 질문(계량적 평가)과 함께 지역주민이 현황에 관하여 인식하는 정도를 답하는 질문(비-계량적 평가, 리커트 5점 척도 이용)을 함께 구성하였다. 조사범위는 식수위생사업 범위에 있는 Gurage Zone 24개 마을, 301 가구, 400명의 주민을 대상으로 설문조사를 실시하였다.

• Journal of Astronomy and Space Sciences
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• v.40 no.3
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• pp.93-100
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• 2023

A study of uncertainty analysis was conducted on four key thermophysical properties of molten Platinum using a noncontacting levitation technique. More specifically, this work demonstrates a detailed reporting of the uncertainties associated with the density, volumetric thermal expansion coefficient, surface tension and viscosity measurements at higher temperatures for a widely used refractory metal, Platinum using electrostatic levitation (ESL). The microgravity experiments were conducted using JAXA's Electrostatic Levitation Furnace (ELF) facility on the International Space Station and the terrestrial experiments were conducted using NASA's Marshal Space Flight Center's ESL facility. The performance of these two facilities were then quantified based on the measurement precision and accuracy using the metrological International Standards Organization's Guide to the Expression of Uncertainty Measurement (GUM) principles.

• Journal of Mushroom
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• v.2 no.4
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• pp.207-213
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• 2004

The results of examining characteristics of mycelial growth and culture condition for determining the condition of artificially culturing Fomitopsis pinicola are as follows. 1) Mycelial growth and density of F. pinicola. were the highest in the medium of PIDA(Pine Dextrose Agar;66.3mm/10d) followed by the order of GDA, PDA, CDA, PODA, ODA, YM, MCM, MEA(pH 4.7), CHA, and MEA(pH 4.7). 2) Optimal temperature for the mycelial growth and density of F. pinicola were shown to be $30^{\circ}C$, but the mycelia were dead at $40^{\circ}C$. the mycelial growth and density of KNAC9005 strains was the highest at $30^{\circ}C$(66.3mm/10d) followed by the order of 25, 20, 15, 35, 10, and $5^{\circ}C$. 3) Optimal pH for the mycelial growth and density of $40^{\circ}C$ was revealed to be 6.0(88.4mm/10d). above or below pH 6.0, the mycelial growth and density were shown to be retarded. 4) Optimal carbon, nitrogen and organic acid sources for the spawn growth of $40^{\circ}C$ were maltose(331mg/25ml/15d), peptone(347mg/25ml/15d), and glutamic acid(357mg/25ml/15d), respectively. Optimal level of biotin was 370mg/15d and optimal C/N ratio was 40.

• Journal of Society of Preventive Korean Medicine
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• v.19 no.2
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• pp.23-35
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• 2015

Objective : As part of the Korean Medicine Official Development Assistance(ODA) and Public Health Project, we implemented a obesity management program(OMP) using Korean medicine in Uzbekistan and its follow-up study was conducted to evaluate the effectiveness of the program. Method : We recruited the participants of whose Body Mass Index(BMI) were over $25kg/m^2$ and who agreed to participate in the program at the South Korea-Uzbekistan Friendship Korean Medical Hospital in Uzbekistan. The program consisted of auricular acupuncture, functional food, and education program on diet and exercise. It was provided once a week during 7-week period. Anthropometric measurements and blood test measuring total cholesterol, triglyceride, and glucose were performed at the baseline, the end of the program, and 10-month follow-up. At the end of the program and the follow-up, survey on satisfaction and self-evaluation of the effectiveness of the program was additionally conducted. Results : 43 out of 78 participants completed the program and were included in the analysis. The analysis of the main outcomes showed that there were significant decreases in anthropometric measurements such as body weight, waist circumference, body mass index (BMI) and body fat content as well as blood test including triglycerides, total cholesterol and blood glucose levels. In the follow-up study, 24 subjects participated and 19 subjects (79.1%) reported that they succeeded in weight control. Furthermore, many participants reported that they maintained healthy lifestyles like healthy diet and regular exercise. The satisfaction with the program was also relatively high, and the education program was selected as the most motivating intervention for weight control. The outcomes such as body weight, BMI, body fat content, and blood glucose level were maintained to be at the decreased level; however, waist circumference, total cholesterol and triglycerides levels either returned back to the baseline level or were elevated to the level higher than the baseline. Conclusion : This study suggests that the OMP using Korean medicine may contribute to weight control of obese population in Uzbekistan. It is meaningful in that the study shows the possibility of implementing health promotion programs using Korean medicine in other countries with different cultures. In the future, more efforts to evaluate the effectiveness of the programs using rigorous methodologies and utilize the effective programs in ODA project will be needed.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.185-192
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• 1998

Four kinds of polyamicacids(PAAs) were prepared by the condensation reaction of four diamines with different linkages, 3,3'-diaminodiphenyl sulfone(3,3'-$DDSO_2$), 4,4'-diaminodiphenyl sulfone(4,4'-$DDSO_2$), 4,4'-methylene dianiline(4,4'-MDA) and 4,4'-oxydianiline(4,4'-ODA), and dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) using the solvent, dimethylacetamide(DMAc). These four PAAs were blended with poly[2,2-(m-phenylene)-5,5'-bibenzimidazole](PBI) from the solution blending. Then called as Blend-I, II, III, and IV, respectively. Cast films or precipitated powders of the PBI/PAA blends were cured at a higher temperature than expected Tg to transform into PBI/PIs blends. Miscibility, specific intermolecular interaction for miscibility and their relative strength as a function of polyimide chemical structure with different four diamines in the PBI/PI systems were investigated. Four blends used in this study were all miscible, and the specific intermolecular interactions existing in these blends was thought to be the hydrogen bonding between the N-H of PBI and the C=O of PIs. The hydrogen bonding in the blends were shown to be stronger in the Blend-III and Blend-IV than Blend-I and II. It is speculated that the differences of hydrogen bonding strength of PBI/PI blends are dependent upon chemical structures of PIs, that is, PIs consisting of $SO_2$ group have a weaker hydrogen bonding strength than those of O or $CH_2$ group because the former has a larger spacer than the latter.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.45-52
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• 2010

Two different imide oligomers(6FDA-ODA/APA and 6FDA-MDA/MA) having crosslinkable end groups were prepared by using a solution imidization method and their properties were investigated. Also, semi-interpenetrating polymer networks(semi-IPN) were prepared using the blends of imide oligomers with polyetherimide $Ultem^{(R)}$, which is used in dual-ovenable packaging materials. The characteristic properties of semi-IPN films were interpreted by using TGA, Thin Film Diffusion Analyzer, and WAXD. Molecular weights of imide oligomers were successfully controlled utilizing 2-aminophenylacetylene(APA) and maleic anhydride(MA) as an endcapping agent. Exotherm reactions by crosslinking appeared and the amount of exthotherm heat was linearly increased as the content of imide oligomers was increased. For semi-IPNs of $Ultem^{(R)}$ and imide oligomers, 5% and 10% weight loss temperatures increased as the contents of imide oligomers were increased. Diffusion coefficient and water uptake of semi-IPNs decreased as the content of imide oligomers was increased, which might be resulted from hydrophobic fluorine group and high packing density. It was concluded that relatively low thermal stability and hydrolytic stability of polyetherimide $Ultem^{(R)}$ were improved by incorporating new developed imide oligomers.

• Macromolecular Research
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• v.17 no.12
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• pp.976-986
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• 2009

With the study goal of firstly elucidating the anisotropic interactions between oriented polymer chain segments and liquid crystal (LC) molecules, and secondly of determining the contributions of the chemical components of the polymer segments to the film surface topography, LC alignment, pretilt, and anchoring energy, we synthesized three dianhydrides, 1,4-bis(4'-t-butylphenyl)pyromellitic dianhydride (BBPD), 1,4-bis(4'-trimethylsilylphenyl)pyromellitic dianhydride(BTPD), and 2,2'-bis(4"-tert-butylphenyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (BBBPAn), and a series of their organosoluble polyirnides, BBPD-ODA, BBPD-MDA, BBPD-FDA, BTPD-FDA, and BBBPAn-FDA, which contain the diamines 4,4'-oxydianiline (ODA), 4,4'-methylenediamine (MDA), and 4,4'-(hexafluoroisopropylidene)dianiline (FDA). All the polyimides were determined to be positive birefringent polymers, regardless of the chemical components. Although all the rubbed polyimide films exhibited microgrooves which were created by rubbing process, the film surface topography varied depending on the polyimides. In all the rubbed films, the polymer chains were unidirectionally oriented along the rubbing direction. However, the degree of in-plane birefringence in the rubbed film varied depending on the polyimides. The rubbing-aligned polymer chains in the polyimide films effectively induced the alignment of nematic LCs along their orientation directors by anisotropic interactions between the preferentially oriented polymer chain segments and the LCs. The azimuthal and polar anchoring energies of the LCs ranged from $0.45{\times}10^{-4}\;-\;1.37{\times}10^{-4}\;J/m^2$ and from $0.86{\times}10^{-5}\;-\;4.26{\times}10^{-5}\;J/m^2$, respectively, depending on the polyimides. The pretilt angles of the LCs were in the range $0.10-0.62^{\circ}$. In summary, the soluble aromatic polyimides reported here are promising LC alignment layer candidates for the production of advanced LC display devices.