패류양식장에서 패류는 먹이 공급 능력과 먹이의 크기에 따라 성장에 차이가 발생할 수 있다. 특히 패류가 소형식물플랑크톤 (>20μm)인 규조류를 섭식할 때 높은 성장을 보인다. 본 연구는 가막만 패류양식장의 먹이 자원 변화를 파악하기 위해 크기별 Chlorophyll a와 기초생산력을 계절별로 조사했다. 크기별 Chl.a 비율은 모든 계절의 GM5정점에서 소형식물플랑크톤 비율이 높게 나타났다. 2월 가막 만 내 낮은 미소식물플랑크톤(2-20μm) 비율은 11월에 증가하는 경향을 보였으며, 이러한 변화는 패류의 섭식 활동과 수온 상승의 영향으 로 판단된다. 이와 더불어 POC/Chl.a ratio가 100 이상으로 나타나 식물플랑크톤 외 유기물 기여가 크게 나타났다. 기초생산력은 광량과 수 온이 높은 8월과 11월에 각각 평균 614±384, 387±439mgC m-2 d-1로 높게 나타났다. 이는 높은 광량과 수온으로 인해 식물플랑크톤의 탄소 흡수율이 증가했기 때문으로 해석된다. 가막만의 기초생산력은 영양염보다 수온과 Chl.a의 영향이 더 크게 작용한 것으로 나타났으며, 패 류에게 공급 가능한 먹이원은 식물플랑크톤 외 유기물이 비교적 크다고 판단된다.

In this study, foamed glass was fabricated by adjusting the final heat treatment temperature. The heat treatment temperatures ranged from 900 °C to 1,100 °C at 50 °C intervals. Blast furnace slag (BFS) powder was mixed with foaming agent such as CaCO3, Ca3(PO4)2, Na2SiO3 and NaOH, pressed under compression, then heat treated to form a porous and stable glass structure. Their optical, thermal, and physical properties, including thermal coefficient, density, glass transition temperature (Tg) and X-ray diffraction patterns, were investigated. As the heat treatment temperature increased, the apparent density decreased from 1.44 g/cm3 to 1.03 g/cm3 while the porosity increased from 46.03 % to 58.89 %. Thermal coefficient decreased from 9.997 × 10-6 /K to 9.417 × 10-6 /K. The main XRD peak gradually shifted toward a lower angle, indicating an expansion of the glass network structure. Results showed that foamed glass based on BFS, developed with a porous structure, can be used as an effective thermal insulation material, suggesting the potential for the commercial utilization of slag.

This study investigates the vitrification of blast furnace slag (BFS) by adjusting the content of steel slag and the added amount of E-glass. SaEb glasses were prepared with a composition of x wt% BFS and (100-x) wt% E-glass (x = 10, 20, 30, 40, and 50). Each composition was melted in a platinum crucible under atmospheric conditions at 1,500 °C for 2 h, and transparent glasses with a transmittance exceeding 75 % were fabricated. All SaEb glasses exhibit an amorphous pattern, indicating successful vitrification. We also analyzed their optical, thermal, and physical properties, including Fourier transform infrared spectroscopy (FT-IR), glass transition temperature (Tg), and x-ray pattern. As the E-glass content increased, the glass transition temperature of blast furnace slag-based glass decreased from 765 °C to 734 °C due to the weakening of the SiO4 unit structure. In all compositions, the glass transition–crystallization temperature difference exceeded 220 °C, confirming the glasses stability for slag fiber applications. The blast furnace slag-based glass exhibits potential for application in slag fiber production, and is expected to provide fundamental data for future studies on related materials.

Organic-inorganic hybrid coating films have been used to increase the transmittance and enhance the physical properties of plastic substrates. Sol-gel organic-inorganic thin films were fabricated on polymethylmethacrylate (PMMA) substrates using a dip coater. Metal alkoxide precursor tetraethylsilicate (TEOS) and alkoxy silanes including decyltrimethoxysilane (DTMS), 3-glycidoxypropyltrimethoxysilane (GPTMS), phenyltrimethoxysilane (PTMS), 3-(trimethoxysilyl)propyl methacrylate (TMSPM) and vinyltrimethoxysilane (VTMS) were used to synthesize sol-gel hybrid coating solutions. Sol-gel synthesis was confirmed by the results of FT-IR. Cross-linking of the Si-O-Si network during synthesis of the sol-gel reaction was confirmed. The effects of each alkoxy silane on the coating film properties were investigated. All of the organicinorganic hybrid coatings showed improved transmittance of over 90 %. The surface hardness of all coating films on the PMMA substrate was measured to be 4H or higher and the average thickness of the coating films was measured to be about 500 nm. Notably, the TEOS/DTMS coating film showed excellent hydrophobic properties, of about 97°.

The semiconductor and display industries require the development of plasma resistant materials for use in high density plasma etching process equipment. Yttria (Y2O3) is a ceramic material mainly used to ensure good plasma resistance properties, which requires a dense microstructure. In commercial production, a sintering process is applied to reduce the sintering temperature of Y2O3. In this study, the effect of the addition of glass frit to the sintered specimen was examined when manufacturing yttria sintered specimens for semiconductor process equipment parts. The Y2O3 specimen was shaped into a Ø50 mm size and then sintered at 1,600 °C for 1~8 h. The characteristics, X-ray diffraction pattern, densities, contraction rate of the specimen, and swelling of the surface of the Y2O3 specimens were investigated as a function of the sintering time and glass frit addition. The Y2O3 specimen exhibited a density of over 4.9 g/cm3 as the sintering time increased, and the swelling phenomenon characteristics were improved by glass frit, by controlling particle size.

네오니코티노이드계 농약은 전세계적으로 사용되는 강력한 살충제이지만 환경, 생물에 잔류하 여 악영향을 미치고 있다. 이에 본 연구는 네오니코티노이드계 농약인 imidacloprid와 clothianidin이 공시 작물인 알팔파와 적용작물로 고추와 오이를 선정하여 토양처리 및 경엽처리에 따른 꿀벌 독성과 엽상 잔류 량을 비교하여 기존 엽상잔류독성시험법의 문제점을 확인하고자 하였다. Imidacloprid와 clothianidin을 작 물 또는 토양에 권장량 및 배수로 처리하고 시간에 따른 꿀벌의 치사율에 대한 RT25를 확인하고 잎의 잔류 농약을 HPLC로 측정하였다. 그 결과 경엽처리하였을 때 imidacloprid은 공시작물 RT25가 1일 이하, 잔류 량은 1.07 ~ 19.27 mg/kg이나 적용작물은 RT25가 9일 이하, 잔류량은 1.00 ~ 45.10 mg/kg 수준이었다. clothianidin은 공시작물 RT25가 10일 이하, 잔류량은 0.61 ~ 2.57 mg/kg이나 적용작물은 RT25가 28일 이 하, 잔류량은 0.13 ~ 2.85 mg/kg 수준이었다. 토양처리했을 때 imidacloprid와 clothianidin은 공시작물에 서는 꿀벌에 영향을 미치지 않았으며 잔류량은 0.05 ~ 0.37 mg/kg 수준이었으나, 적용작물에서는 imidacloprid은 RT25가 28일 이하였고 잔류량은 4.47 ~ 130.43 mg/kg 수준이었고, clothianidin은 RT25가 35일 이하였고, 잔류량은 5.96 ~ 42.32 mg/kg 수준이었다. 결론적으로 꿀벌 독성과 엽상 잔류량을 작물간 비교하였을 때 공시작물 보다 적용작물이 꿀벌의 치사율에 많은 영향을 미치고 잔류량도 높게 나타났고, 처리방법에 따라 비교하였을 때 적용작물에 대한 토양처리가 경엽처리에 비해 높은 RT25와 잔류량이 나타 났다. 따라서 농약안전성 확보를 위해 제시된 시험법이 실제 적용작물과 농약 처리방법에 따라 차이가 있 을 수 있어 imidacloprid와 clothianidin의 안전성 평가를 위하여 다양한 경로의 연구가 필요하다.

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.

우리나라 해양환경에 유출되는 위험·유해물질(Hazardous Noxious Substances, HNS)의 해양환경 및 사회환경 영향평가 결과 와 HNS 확산 영역, 해양환경 정보, HNS 실태조사 결과 등 관련 연구 결과 및 자료를 정책결정자와 연구자들에게 공유할 수 있는 HNS 국내 용 플랫폼을 구축하고자 한다. 국내의 HNS 관리 및 배출 체계 마련을 위한 의사결정 지원이 가능하고 국내 실정에 적합한 플랫폼의 설계 를 위하여 유해물질의 데이터 관리 및 유출 시 대응 도구, 기초적인 정보 등 플랫폼에 관련된 기술동향을 분석하는 등 국내·외의 플랫폼 개발 사례를 고찰하였다. 유속 벡터의 전처리 기능 개발, 전처리 결과에 따른 동적 시각화 구현, 해양산업시설 배출 HNS의 유출량과 유출 범위의 전처리 모듈, HNS 해양환경 영향평가 연산 모듈 프로토타입을 개발하였다. HNS 해양환경 영향평가를 위한 국내용 HNS 플랫폼은 초기 위해성을 평가하고 대응 및 관련 법제화 시 과학적인 기초 도구로써 활용될 수 있을 것으로 기대된다.

In this study, changes in the microbial ecosystem of the Yeongheungdo island coastal waters were investigated for five years to collect basic data. To evaluate the influence of distance from the coast on the microbial ecosystem, four sites, coastal Site (S1) and 0.75, 1.5, and 3 km away from the coast, were set up and the changes in physicochemical and biological factors were monitored. The results showed seasonal changes in water temperature, dissolved oxygen, salinity, and pH but with no significant differences between sites. For nutrients, the concentration of dissolved inorganic nitrogen increased from 6.4 μM in April-June to 16.4 μM in July-November, while that of phosphorus and silicon phosphate increased from 0.4 μM and 2.5 μM in April-June to 1.1 μM and 12.0 μM in July-November, respectively. Notably, phosphorus phosphate concentrations were lower in 2014-2015 (up to 0.2 μM) compared to 2016-2018 (up to 2.2 μM), indicating phosphorus limitation during this period. However, there were no differences in nutrients with distance from the coast, indicating that there was no effect of distance on nutrients. Phytoplankton (average 511 cells mL-1) showed relatively high biomass (up to 3,370 cells mL-1) in 2014-2015 when phosphorus phosphate was limited. Notably, at that time, the concentration of dissolved organic carbon was not high, with concentrations ranging from 1.1-2.3 mg L-1. However, no significant differences in biological factors were observed between the sites. Although this study revealed that there was no disturbance of the ecosystem, further research and more basic data on the microecosystem are necessary to understand the ecosystem of the Incheon.

Porous ceramics are used in various industrial applications based on their physical properties, including isolation, storage, and thermal barrier properties. However, traditional manufacturing environments require additional steps to control artificial pores and limit deformities, because they rely on limited molding methods. To overcome this drawback, many studies have recently focused on fabricating porous structures using additive manufacturing techniques. In particular, the binder jet technology enables high porosity and various types of designs, and avoids the limitations of existing manufacturing processes. In this study, we investigated process optimization for manufacturing porous ceramic filters using the binder jet technology. In binder jet technology, the flowability of the powder used as the base material is an important factor, as well as compatibility with the binder in the process and for the final print. Flow agents and secondary binders were used to optimize the flowability and compatibility of the powders. In addition, the effects of the amount of added glass frit, and changes in sintering temperature on the microstructure, porosity and mechanical properties of the final printed product were investigated.