본 연구의 목적은 금속 중공사형 필터에 무기 입자를 코팅하여 금속/세라믹 복합 한외여과막을 제조하는 것이다. 직경이 2.0 mm이며 기공 크기가 2~8 μm 범위를 갖는 니켈 중공사 필터에 급냉건조법과 침지-건조법으로 실리카 졸과 티타니아 졸을 코팅하여 금속쎄라믹 복합 한외여과막을 제조하였다. SEM과 PMI 결과로부터 기공 크기가 50 nm 수준을 갖는 것을 확인하였다. 기공 크기는 입자 크기, 소성시간 및 온도에 따라 차이를 보였다.

Silicon carbide (SiC) is a promising material for power device applications due to its wide band gap(3.26 eV for 4H-SiC), high critical electric field and excellent thermal conductivity. The Schottky barrier diodeis the representative high-power device that is currently available commercially. A field plate edge-terminated4H-SiC was fabricated using a lift-off process for opening the Schottky contacts. In this case, Ni/Ti dual-metalcontacts were unintentionally formed at the edge of the Schottky contacts and resulted in the degradation ofthe electrical properties of the diodes. The breakdown voltage and Schottky barrier height (SBH, ΦB) was 107V and 0.67eV, respectively. To form homogeneous single-metal Ni/4H-SiC Schottky contacts, a deposition andetching method was employed, and the electrical properties of the diodes were improved. The modified SBDsshowed enhanced electrical properties, as witnessed by a breakdown voltage of 635V, a Schottky barrier heightof ΦB=1.48eV, an ideality factor of n=1.04 (close to one), a forward voltage drop of VF=1.6V, a specific onresistance of Ron=2.1mΩ-cm2 and a power loss of PL=79.6Wcm-2.

줄포만 갯벌의 체계적이고 과학적인 관리를 위하여 갯벌 퇴적물을 대상으로 입도특성 및 유기물 그리고 중금속 조사를 실시하였고, 퇴적물중의 중금속 오염도를 평가하였다. 줄포만 전체 갯벌의 입도는 연안과 직각방향인 F라인에서 대부분 Clay질이 우세한 반면, 만의 연안측면에 위치한 R과 L라인에서 Silt질이 우세한 것으로 나타나서 Silt-Clay 또는 Clay-Silt가 대부분이었다. 평균입경은 3.7 Φ~ 10.4 Φ의 범위로 평균 7 Φ 이상의 높은 평균입도를 나타내어 퇴적물 분류학상 세립질 퇴적물(4 Φ 이상)에 해당되었다. 퇴적물의 유기물 농도는 연안에서 직각방향으로 뻗은 F라인에서 높게 나타난 반면, 연안 측면을 따라 조사된 L과 R라인에서 상대적으로 낮게 나타났다. 갯벌 퇴적물의 중금속 분포를 보면 연안의 직각방향인 F라인보다 연안측면의 R과 L라인에서 대체적으로 높은 중금속 농도를 나타내고 있었다. 유기물과 입도는 양호한 상관성을 보였고, 입도 평균치와 중금속의 일부 원소와 양호한 상관성을 나타내었지만, 중금속 원소간에는 약간의 상관성은 있었으나 대체적으로 낮은 상관계수를 보였다. 중금속 오염도 평가를 위하여 미국 EPA와 NOAA 그리고 한국 환경정책평가연구원에서 제시한 중금속 오염기준을 적용해 보았다. 줄포만 갯벌퇴적물의 중금속 오염도는 미국 EPA 기준에서 항목별 편차는 있었으나 대부분이 Nonpolluted와 Moderaterly polluted에 속하였고, NOAA의 기준에서는 대부분이 ERL 이하의 오염수준을 보였다. 한국 환경정책평가연구원에서 제시한 기준안에서는 대부분이 목표수준 이하의 값을 나타내었다.

The acrylic coating emulsions were prepared by the emulsion polymerization to protect the surface of steel plate from the corrosion chemicals like acid, base and salt water. MMA(methyl methacrylate), styrene, BA(butyl acrylate), and 2-HEMA(2-hydroxyethyl methacrylate) were used as monomer. KPS(potassium persulfate) and SBS(sodium bisulfite) as redox initiator and SDBS(sodium dodecylbenzene sulfonate) as emulsifier were used on the emulsion polymerization reaction. The most stable in-situ coating was obtained when 10% of MMA was added. Both particle size and quantity in emulsion were decreased as increasing the mount of SDBS. the most stable prepared coating emulsion with polyisocyanate crosslinker showed very high anticorrosion properties on the coated steel layer to salt water, whereas no significant improvement of anticorrosion property to acdic and basic condition it showed.

Heavy metal concentration of Fe, Zn, Cu, Cd and Pb were analysed from seaweeds (Ulva pertusa, Sargassum thunbergii, Caulacanthus okamurae), sediments and seawater at the two experimental sites of Daebul and Sabjin industrial complex in Mokpo coastal area

Growth behavior of InGaN/GaN self-assembled quantum dots (QDs) was investigated with respect to different growth parameters in low pressure metalorganic chemical vapor deposition. Locally formed examples of three dimensional InGaN islands were confirmed from the surface observation image with increasing indium source ratio and growth time. The InGaN/GaN QDs were formed in Stranski-Krastanow (SK) growth mode by the continuous supply of metalorganic (MO) sources, whereas they were formed in the Volmer-Weber (V-W) growth mode by the periodic interruption of the MO sources. High density InGaN QDs with 1~2nm height and 40~50nm diameter were formed by the S-K growth mode. Dome shape InGaN dots with 200~400nm diameter were formed by the V-W growth mode. InN content in InGaN QDs was estimated to be reduced with the increase of growth temperature. A strong peak between 420-460 nm (2.96-2.70 eV) was observed for the InGaN QDs grown by S-K growth mode in photoluminescence spectrum together with the GaN buffer layer peak at 362.2 nm (3.41 eV).

Electrical properties of multi-channel metal-induced unilaterally precrystallized polycrystalline silicon thin-film transistor (MIUP poly-Si TFT) devices and circuits were investigated. Although their structure was integrated into small area, reducing annealing process time for fuller crystallization than that of conventional crystal filtered MIUP poly-Si TFTs, the multi-channel MIUP poly-Si TFTs showed the effect of crystal filtering. The multi-channel MIUP poly-Si TFTs showed a higher carrier mobility of more than 1.5 times that of the conventional MIUP poly-Si TFTs. Moreover, PMOS inverters consisting of the multi-channel MIUP poly-Si TFTs showed high dynamic performance compared with inverters consisting of the conventional MIUP poly-Si TFTs.

Objective of this study was to investigate residual the levels of heavy metals in rice grain and soils of “Top-Rice” and common rice cultivation areas from 2005 to 2007. Soil and rice grain samples were taken from 33 “Top-rice” areas and neighboring paddies, and analyzed for the elements using ICP-OES and ICP-TOF-MS after acid digestion. A concentration of arsenic in paddy soil was 1.33 mg/kg which was below 1/5-1/11 fold of the threshold levels (concern: 4 mg/kg, action: 10 mg/kg), and paddy soil was 0.06 mg/kg of Cd (cadmium) being below 1/25-1/67 fold of the limits (concern: 1.5 mg/kg, action: 4 mg/kg). A level of Cu (copper) in paddy soil was 4.57 mg/kg which was below 1/11-1/27 fold of the threshold levels (concern: 50 mg/kg, action: 125 mg/kg), and Pb (lead) concentration in paddy soil was found to be a 4.68 mg/kg. In addition, Hg (mercury) concentration in paddy soil was to be a 0.03 mg/ kg, which was below 1/131-1/328 fold of the threshold levels (concern: 4 mg/kg, action: 10 mg/kg). The average concentrations of As, Cd, Cu, Pb and Hg in the polished rice samples were 0.037, 0.043, 0.280, 0.048 and 0.002 mg/kg, respectively. These levels are lower than those of other countries in rice grains. Assuming the rice consumption of 205.7 g/day by total dietary supplements in Korea, the amount of total weekly metal intake of As, Cd, Cu, Pb and Hg by polished rice were estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 μg/kg body weigh/week, respectively. The PTWI(%) of As, Cd, Cu, Pb and Hg were 5.95 (inorganic arsenic), 0.26 (total arsenic), 14.79, 0.19, 4.65 and 1.07% estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 μg/kg body weigh/week, respectively. In conclusion, it was appeared that the heavy metals contamination in the brown and polished rice should not be worried in Korea.

이 연구는 장석 반암에 대한 자연수내 중금속 흡착제로서의 활용 가능성을 검토하기 위해 수행되었다. '맥반석'으로 불리는 연구대상 암석은 프로필리틱 변질작용으로 생성된 녹니석, 녹염석, 방해석을 포함하는 변질 장석반암이다. 용출 실험결과, 용출원소의 대부분은 Ca와 Na이며, 이들은 장석 반정보다는 석기에서 그 용출량이 많다. 흡착 실험결과, Pb, Cu, Fe는 반응 1시간 이내에 각각 99, 98, 97%가 흡착되었으나 As는 24시간 동안 25%가 흡착되었다. 변질 장석 반암의 Pb, Cu, Fe에 대한 높은 흡착능력은 수질정화용 중금속 흡착제로서의 활용 가능성이 있음을 시사한다.

본 연구는 대한민국 서해안 새만금 갯벌지역에서 1999~2000년에 도래한 섭금류 3종의 간에서 철(Fe), 아연(Zn), 구리(Cu), 납(Pb) 그리고 카드뮴(Cd) 농도를 측정하여 비교하고, 각 원소 사이의 상관관계를 분석하였다. 연구결과 철(ANOVA, p=0.018), 구리(ANOVA, p=0.043), 납(ANOVA, p〈0.001) 그리고 카드뮴(ANOVA, p=0.016)은 종간에 유의한 차이가 나타났지만 아연에서는 유의한 차이가 나타나지 않았다. 본 연구에서 나타난 철, 아연 그리고 구리와 같은 필수원소는 조류의 체내 신진대사에 필요한 정상범위 내의 농도로 생각된다. 오염원소인 납 농도는 붉은어깨도요 Calidris tenuirostris (5.76±2.14μg/dry g)는 비오염수준이었지만 좀도요 Calidris ruficollis(29.4±10.6μg/dry g)와 뒷부리도요 Xenus sinereus(15.9±11.9μg/dry g)는 오염수준이었으며, 특히 좀도요는 중독수준에 근접하였다. 카드뮴 농도는 뒷부리도요(0.82±12μg/dry g)와 붉은어깨도요(0.45±0.53μg/dry g)는 비오염수준의 농도였으나, 좀도요(17.5±22.1μg/dry g)는 오염기준(3μg/dry g)을 초과하였다. 원소간의 상관관계에서는 납과 카드뮴에서만 유의한 관계가 나타났고 (r=0.067, p〈0.01), 다른 원소는 상관관계가 나타나지 않았다.

진해만의 가덕수도 표층 해수 중의 증금속은 육지에 가까운 정점에서 높은 분포를 나타내었으며, 이들의 븐포에는 조사 해역의 염분에 근거한 물리적 혼합은 크게 작용하지 않았다. 그리고 Pb를 제외한 다른 중금속은 과거와 큰 차이를 나타내지 않았다. 표층 퇴적물의 중금속 함량은 거제도 혹은 가덕도에 인접한 정점에서 높게 나타났으며, 이들 해역의 Zn, Eu와 Pb 함량은 과거에 비해 약간 상승하여 인위적인 영향이 있는 것으로 판단된다. Hg과 Pb을 제외한 중금속은 상호간에 양호한 상관성을 보였으면, Eo, Ni, Zn, Eu, As와 Ed는 IL 및 COD와도 좋은 상관성을 보였다. 평균지각을 기준으로 한 농축계수는 As>Cd>Pb>Zn>Co>Cu>Hg>Ni의 순이 었으며, As, Ed, Ni, Pb, Zn은 전 정점에서 1 이상이었다. 한반도 연안 퇴적물의 중금속 배경 농도에 근거한 Ni과 Rn의 농축계수는 지각평균에 의한 농축계수보다 낮았고, Cu는 높게 나타났다.

The objective of the present study is to investigate the increase in the functional characteristics of a substrate by the formation of a thin coating layer. Thin coating layers of have high potential because exhibits high hardness. Shock induced reaction synthesis is an attractive fabrication technique to synthesize uniform coating layer by controlling the shock wave. Ti and Si powders to form using shock induced reaction synthesis, were mixed using high-energy ball mill into small scale. The positive effect of this technique is highly functional coating layer on the substrate due to ultra fine substructure, which improves the bonding strength. These materials are in great demand as heat resisting, structural and corrosion resistant materials. Thin coating layer was successfully recovered and showed high Vickers' hardness (Hv=1183). Characterization studies on microstructure revealed a fairly uniform distribution of powders with good interfacial integrity between the powders and the substrate.

최근프린팅기술은 전자부품소재 산업의 대형화 및 저가격화의 해법으로 기대되고 있다. 특히 전자부품소재 프린팅 기술 중 잉크젯공정은 최신 디스플레이용 전극소재, PCB, FPCB 및 기타 소재공정에 이용하려는 움직임이 활발히 진행되고 있다. 그러나 잉크젯 기술은 재료의존도 비중이 높은 기술로서 소재(금속잉크)의 개발이 최우선시 되어야한다. 전자부품소재용 금속잉크에 사용되는 금속 나노입자는 우수한 전기전도성과 산업적응용이 가능해야 한다. 따라서 최근 연구되고

The morphology of three-dimensional (3D) cross-linked electrodeposits of copper and tin was investigated as a function of the content of metal sulfate and acetic acid in a deposition bath. The composition of copper sulfate had little effect on the overall copper network structure, whereas that of tin sulfate produced significant differences in the tin network structure. The effect of the metal sulfate content on the copper and tin network is discussed in terms of whether or not hydrogen evolution occurs on electrodeposits. In addition, the hydrophobic additive, i.e., acetic acid, which suppresses the coalescence of evolved hydrogen bubbles and thereby makes the pore size controllable, proved to be detrimental to the formation of a well-defined network structure. This led to a non-uniform or discontinuous copper network. This implies that acetic acid critically retards the electrodeposition of copper.

Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of 700 μm was formed by a heat treatment at 665˚C for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.