본 연구는 폴리케톤(PK) 지지체를 이용한 유기용매 역삼투(OSRO) 분리막 제조를 목적으로 하였다. 비용매 유도 상분리 방법(NIPS)을 통해 PK 지지체를 제작하였고, PK 지지체 위에 polyamide layer를 계면 중합하여 thin-film composite (TFC) 형태로 OSRO 분리막을 완성하였다. 이후 OSRO 분리막의 표면과 단면 구조 및 표면의 화학적 구조를 분석하였고 수 투과도와 염 제거율은 각각 약 1.28 LMH/bar와 99.0%의 결과를 얻었다. 또한 OSRO 분리막의 polyamide layer는 유기용매 침지 1일 동안 매우 안정적이었고, 단일 유기용매 투과도 경향성은 유기용매 나노여과(OSN) 분리막의 투과도 모델과 일치하 였다. OSRO 분리막의 MWCO는 MeOH 상에서 240 g/mol이었다. OSRO 분리막의 MeOH-toluene 혼합용액에 대한 투과도 와 separation factor는 상용 OSN 분리막보다 각각 200%와 60%의 높은 결과를 얻었다.

우리나라의 도농복합시는 1995년 지방자치제도가 시행되면서 등장한 도시 유형으로, 도시와 농촌의 균형발전을 목적으로 시행되고 있다. 본 연구는 우리나라 54개 도농복합시를 대상으로 인구, 사회, 경제, 인프라의 4개 영역, 14개 지표로 구성된 도시역량 지표를 종합지수화하여 2010년과 2020년의 도농복합시 도시역량의 공간 분포 패턴 및 변화를 실증적으로 탐색한다. 주요 연구 결과는 다음과 같다. 첫째, 인구가 많은 도시일수록 도시역량이 높은 경향이 나타났다. 둘째, 2010년부터 2020년까지 전반적으로 도농복합시 도시역량 지수의 범위가 축소되는 경향이 나타났다. 셋째, 세 집단으로 유형화한 도농복합시의 도시역량 의 차이를 비교한 결과, 유의미한 차이가 확인되었다.

The purpose of this study is to analyze the correlation between ecotoxicity and water quality items using Daphnia magna in public sewage treatment plant process and to obtain operational data to control ecotoxicity through research on removal efficiency. The average value of ecotoxicity was 1.39 TU in the influent, 1.50 TU in the grit chamber, and 0.84 TU in the primary settling tank and it was found that most organic matters, nitrogen, and phosphorus were removed through biological treatment in the bioreactor. Using Pearson’s correlation analysis, the positive correlation was confirmed in the order of ecotoxicity and water quality items TOC, BOD, T-N, NH3-N, SS, EC, and Cu. As a result of conducting a multilinear regression analysis with items representing positive correlation as independent variables, the regression model was found to be statistically significant, and the explanatory power of the regression model was about 81.6%. TOC was found to have a significant effect on ecotoxicity with B=0.009 (p<.001) and Cu with B=16.670 (p<.001), and since the B sign is positive (+), an increase of 1 in TOC increases the value of ecotoxicity by 0.009 and an increase in Cu by 1 increases the value of ecotoxicity by 16.670. TOC (β=0.789, p<.001) and Cu (β=0.209, p<.001) were found to have a significant positive effect on ecotoxicity. TOC and Cu have a great effect on ecotoxicity in the sewage treatment plant process, and it is judged that TOC and Cu should be considered preferentially and controlled in order to efficiently control ecotoxicity.

The objective of this study is to analyze the indoor air quality of multi-use facilities using an IoT-based monitoring and control system. Thise study aims to identify effective management strategies and propose policy improvements. This research focused on 50 multi-use facilities, including daycare centers, medical centers, and libraries. Data on PM10, PM2.5, CO2, temperature, and humidity were collected 24 hours a day from June 2019 to April 2020. The analysis included variations in indoor air quality by season, hour, and day of the week (including both weekdays and weekends). Additionally, ways to utilize IoT monitoring systems using big data were propsed. The reliability analysis of the IoT monitoring network showed an accuracy of 81.0% for PM10 and 76.1% for PM2.5. Indoor air quality varied significantly by season, with higher particulate matter levels in winter and spring, and slightly higher levels on weekends compared to weekdays. There was a positive correlation found between outdoor and indoor pollutant levels. Indoor air quality management in multi-use facilities requires season-specific strategies, particularly during the winter and spring. Furhtermore, enhanced management is necessary during weekends due to higher pollutant levels.

Daemadeung, located in the estuary of the Nakdong River, is formed by sand dunes and possesses well-developed intertidal flats. This study aimed to investigate the habitat of benthic microalgae, photosynthetic pigments, and photosynthetic efficiency in the intertidal flats of Daemadeung from January to December 2011. The inorganic nitrogen content in the sediment pore water was primarily composed of ammonium, while nitrate+nitrite was dominant in the upper layer water. The concentration of chlorophyll a and fucoxanthin in the sediment surface was significantly higher than the mean of all the sediment layer. The average Fv/Fm of benthic microalgae during the entire survey period was 0.52±0.03, with the highest value (0.61±0.08) observed in February. The rETRmax showed a seasonal trend, being high from spring to early autumn (April to October) and low from winter to early spring (January to March, November, December), with the highest value (153.05±2.30 μmol electrons m-2 s-1) in July and the lowest (38.49±5.17 μmol electrons m-2 s-1) in January. The average Fv/Fm of diurnal microalgae was 0.48±0.03, with the highest value (0.61±0.08) observed at noon. The rETRmax showed a highest peak at noon (54.24±11.35 μmol electrons m-2 s-1) and reached its lowest point at 16:00 (26.17±4.75 μmol electrons m-2 s-1). These findings suggest that the productivity of benthic microalgae varies significantly depending on the survey time and sediment depth. Therefore, to quantify the productivity of benthic microalgae using Diving-PAM, surveys should be conducted based on tidal conditions, and simultaneous pigment analysis of sediment layers should also be performed.

반응성 에시드 클로라이드인 트리멜리틱 안하이드라이드 클로라이드를 이용한 2-에티닐피리딘의 무촉매중 합을 통하여 트리멜리틱 부분을 측쇄로 갖는 이온성 공액구조 고분자를 합성하였다. 2-에티닐피리딘과 트리멜리틱 안하이드라이드 클로라이드를 1:1 몰비로 DMF 용매에서 반응시킨 결과 해당 공액구조 고분자를 높은 수율로 합성 할 수 있었다. 첫 번째 반응 단계에서 만들어진 단량체인 N-치환-2-에티닐피리디늄 염은 별도의 촉매 사용없이도 중합반응이 잘 진행되었다. NMR, IR, UV-visible 등의 분광분석기를 사용하여 합성 고분자의 구조를 분석한 결과 설계한 치환기를 갖는 공액구조 고분자가 합성되었음을 확인할 수 있었다. 합성 고분자의 전기-광학적 특성과 전기 화학적 특성을 측정하였다. 본 고분자는 자외선 영역뿐만 아니라 가시광선 영역에서 500 nm까지 넓은 흡수 피크 를 보였으며 PL 최대값은 539 nm에서 나타났다.

본 연구는 Lactobacillus acidophilus KCTC 3164 균주에 의해 발효된 깻잎 발효 추출물 (5%, 10%, 15%, 및 20% w/v)을 기능성 첨가제로 사용하여 깻잎 발효물이 첨가된 아이스크림을 제조 함이 목적이다. 깻잎 발효물이 첨가된 아이스크림의 물리·화학적 특성(색상, 점도, pH, 총 산도, 녹는 속 도, 오버런) 및 항산화 활성을 평가하였다. 깻잎 발효물 첨가량이 증가할수록 아이스크림의 색상에 영향 을 주었으며, 아이스크림의 녹는 속도도 증가하였다. 이에 반해 점도는 점차적으로 감소하는 경향을 나 타내었다. 깻잎 발효물 첨가량이 높을수록 오버런은 점진적으로 증가하였고, pH는 유의하게 감소하였으 며, 총 산도는 증가하였다. 깻잎 발효물이 첨가된 아이스크림의 DPPH 라디컬 소거능과 총 폴리페놀 함 량은 깻잎 발효물 첨가량이 많아질수록 유의적으로 증가하는 것으로 나타났다. 본 연구결과 10% 깻잎 발효추출물을 함유한 아이스크림 실험군이 높은 오버런, 낮은 녹는 속도, 원하는 점도, 높은 DPPH 라디 컬 소거능과 총 폴리페놀 함량을 보여 기능성 아이스크림으로의 잠재력이 있는 것을 알 수 있었다.

본 연구에서는 폐타이어를 파쇄한 재생 SBR(Styrene-Butadience Rubber)을 사용하여 탄성 고무 층 의 파단 시의 인장 강도 및 연신도와 같은 인장특성 및 충격 흡수 및 수직 변형과 같은 동적특성을 평가하였고, 섬유 보강재를 혼입하여 탄성 고무 층의 취약점을 개선시키고자 하였다. 주요변수로 다짐 횟수, 바인더-고무분말 비율, 양생기간, 양생온도, 양생습도, 섬유 보강재의 종류를 고려하였다. 실험 결과, 재생 SBR을 사용한 탄성 고무 층의 인장 강도는 다짐 횟수, 바인더-고무분말 비율, 양생기간 및 온도가 증가함에 따라 증가하였으며, 파단 시 연신도는 양생온도와 기간에 영향을 받는 것으로 나 타났다. 충격 흡수와 수직 변형은 다짐횟수 및 바인더-고무분말 비율이 증가함에 따라 경도가 증가하 여 감소하는 경향을 나타내었다. 또한 양생온도가 탄성 고무 층의 인장 특성에 뚜렷한 영향을 미치며, 적절한 양생온도를 유지할 경우(약 50℃) 상대적으로 낮은 탄성 고무 층의 인장 특성을 개선할 수 있는 가능성을 제시하였다. 보강재로 폴리머 합성 섬유인 Polypropylene(PP), Polyester(PET), Nylon(NY)을 1%까지 혼입하는 경우 재생 SBR이 가진 충격 흡수 능력은 그대로 유지하면서, 인장강도를 향상시킬 수 있음을 확인하였다.

Recently, the demand for shape memory alloys in the biomedical industry is increasing. Nitinol alloy, which accounts for most of the shape memory alloy market, occupies most of the biomedical field. Nitinol for biomaterials requires a clean surface without sub-micron surface integrity and surface defects in order to be used more safely in a living body. Among them, new technologies such as polishing using MR fluid are being studied, but there is a disadvantage in that it takes a long time for processing due to a low material removal rate. In this study, material removal studies were conducted for effective polishing, and excellent polishing properties of MR fluid were confirmed.

In this study, infrared thermometry techniques were used to conduct surface wetting performance tests (wicking tests) on micropillar structures with good fluid supply capabilities to enhance the critical heat flux. Wicking tests were conducted based on various micropillar shapes (i.e., diameter and spacing) to investigate the surface wetting performance near the boiling point of the fluid(~100°C). The surface temperature was increased from 20°C to 95°C, to examine the wicking performance The shape of the micropillars were quantified by the roughness and the effect of the roughness and temperature on the wicking performance was analyzed. As a result, we confirmed that the roughness of the micropillars increases the capillary pressure, improving the wicking performance. The sample D04 G10 with the highest roughness coefficient at room temperature (r=2.51) exhibited the highest wicking coefficient, showing a 170% improvement in wicking performance compared to D04G20 with the smallest roughness coefficient at room temperature(r=1.51). Additionally, the D04 G10 sample (r=2.51) recorded a 50% improvement in the wicking coefficient at the highest temperature(95°C) compared to room temperature(20°C). The wicking coefficient data will be utilized as a database for developing a new correlation for critical heat flux.

This study investigated the physicochemical properties of protein-fortified rice flour by mixing rice flour (RF) with untreated and fermented plant proteins. Fermented faba bean protein concentrate (FMFP) and chickpea flour (FMCF) were prepared by solid-state fermentation of faba bean protein concentrate (UTFP) and chickpea flour (UTCF) using Bacillus subtilis. FMFP and FMCF exhibited higher crude protein, reducing sugar and starch contents more than their counterparts. The increased rate of essential and branched-chain amino acids in FMFP and FMCF exceeded that of crude protein. Adding plant proteins to RF decreased swelling power (SP) and increased solubility in RF-UTFP and RF-FMFP mixtures, while SP and solubility increased in RF-UTCF and RF-FMCF mixtures. All RF-plant protein mixtures showed higher gelatinization temperature and lower gelatinization enthalpy than RF. Thermal gelation was found in all RF-plant protein mixtures, but the RF-FMCF mixture may form weak and unstable gel structures. The increase in pasting viscosity was minimal for the RF-UTFP and RF-FMFP mixtures but more pronounced for the RF-UTCF and RF-FMCF mixtures. Overall, FMFP may be a potential protein source to supplement the protein deficiency in RF with minimal changes in RF-based foods’ rheological and textural properties.

Al2O3 has excellent sintering properties and is important in semiconductor manufacturing processes that require high-temperature resistance and chemical inertness in a plasma environment. In this study, a comprehensive analysis of the chemical characteristics, physical properties, crystal structure, and dispersion stability of three commercially available Al2O3 powders was conducted. The aim was to provide a technological foundation for selecting and utilizing appropriate Al2O3 powders in practical applications. All powders exhibited α-Al2O3 as the main phase, with the presence of beta-phase Na2O-11Al2O3 as the secondary phase. The highest Na+ ion leaching was observed in the aqueous slurry state due to the presence of the secondary phase. Although the average particle size difference among the three powders was not significant, distinct differences in particle size distribution were observed. ALG-1SH showed a broad particle size distribution, P162 exhibited a bimodal distribution, and AES-11 displayed a uniform unimodal distribution. Highconcentration Al2O3 slurries showed differences in viscosity due to ion release when no dispersant was added, affecting the electrical double-layer thickness. Polycarboxylate was found to effectively enhance the dispersion stability of all three powders. In the dispersion stability analysis, ALG-1SH exhibited the slowest sedimentation tendency, as evidenced by the low TSI value, while P162 showed faster precipitation, influenced by the particle size distribution.

본 연구에서는 에너지 소모가 큰 기존 진공 증류 공정의 대안으로 친환경이면서 에너지 효율적인 투과증발 분리 공정을 이용하여 1,2 hexane diol/water (1,2 HDO/water) 혼합물에서 물을 분리하는 데 적용되었다. 사용한 분리막은 glutaraldehyde (GA)로 가교된 PVA를 알루미나 중공사 막(Al-HF) 내부에 코팅하여 사용하였다. 1,2 HDO/water 투과증발 분리공 정에서는 PVA/GA 비율, 경화 온도 및 투과증발 분리공정 운전 조건에 대한 막의 최적화를 연구하였다. 장기 안정성 시험에 서 PVA/GA (몰 비율 = 0.08, 경화 온도 = 80°C) 로 코팅된 Al-HF 막이 공정온도 40°C에서 1.90~2.16 kg/m2h 범위의 투과 도를 보였으며, 투과용액의 수분 함량은 99.5% (separation factor = 68) 이상이었다.