• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.227.1-227.1
• /
• 2010

본 연구는 자외선 영역의 흡수로 전자 정공의 전하쌍을 생성함으로써 광전압 및 전류를 일으키는 티타니아 물질을 금속지지체 표면에 양극산화로 튜브형 $TiO_2$(anodized tubular $TiO_2$; ATT)로 제조한 후 나노크기의 금속 혹은 $WO_3$입자를 담지하여 광감응 재료로 활용하였다. 이는 기존의 입자나 콜로이드 형태로 광촉매 물질을 고정화하여 사용한 재료의 탈리현상 및 효율저하를 극복하기 위함이다. ATT는 전해질 내에 전기화학적 에칭율과 화학적 용해율의 비율에 의해 나노튜브 길이 성장에 영향을 미치는데 이를 유기 전해질과 불산 전해질을 사용하여 정전압 혹은 정전류의 조건에서 다양한 길이의 $TiO_2$ 나노튜브를 제조하였다. 여기에 전기분해담지(electrolytic deposition; ELD)를 통하여 정전류 조건에서 다양한 금속(Pt, Pd, Ru)을 나노크기의 형태로 담지하여 광촉매 내 생성된 전자 정공의 재결합을 줄이고자 하였고 $WO_3$의 담지를 통하여 가시광 감응을 높이고자 하였다. 제조된 여러 조건의 시료는 SEM과 EDAX를 통하여 형태와 길이, 담지량을 확인 하고 XRD를 이용하여 열처리 온도에 따른 결정화상태를 확인하였으며 광전류 측정 및 Cr(VI)의 광환원과 MB의 광분해를 통하여 광효율을 관찰하였다. 금속이 도핑되었을 경우 순수 ATT보다 보통 3배의 흡착률과 UV광원 아래 2배의 광효율을 관찰할 수 있었는데 이 중 Pt의 담지가 가장 효율이 좋았으며 흡착률에서는 담지량의 증가에 따른 증가선을 관찰 할 수 있었으나 광원 사용시 3%담지율에서 최적을 확인 할 수 있었다. 또한 $TiO_2$외 가시광감응 활성을 높이기 위한 다양한 광촉매제조가 진행 중에 있다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.06a
• /
• pp.89-89
• /
• 2009

높은 소수반송자 수명(life-time)을 가지는 고품위 실리콘 기판은 고효율 실리콘 이종접합 태양전지 제작을 위한 중요 요소 기술 중 하나이다. 본 연구에서는 n-type c-Si 기판을 이용한 고효율 실리콘 이종접합 태양전지제작을 위해 hot water oxidation(HWO) 공정을 이용하여 고품위 실리콘 기판을 제작하였다. 실리콘 기판의 특성 분석은 Qusi-steady state photoconductance (QSSPC)를 이용하여 소수반송자 수명을 측정하였으며, 기판의 면저항 및 wetting angle을 측정하여 공정에 따른 특성변화를 분석하였다. Saw damage etching 된 기판을 웨이퍼 표면으로부터 particle, 금속 불순물, 유기물 등의 오염을 제거하기 위해 $60{\sim}85^{\circ}C$로 가열된 Ammonia수, 과산화수소수($NH_4OH/H_2O_2/H_2O$), 염산 과산화수소수($HCL/H_2O_2/H_2O$) 및 실온 희석불산(DHF) 중에 기판을 각각 10분 정도씩 침적하여, 각각의 약액 처리 후에 매회 10분 정도씩 순수(DI water)에서 rinse하여 RCA 세정을 진행한 후 HWO 공정을 통해 기판 표면에 얇은 산화막 을 형성시켜 패시베이션 해주었다. HF를 이용하여 자연산화막을 제거시 HWO 공정을 거친 기판은 매끄러운 표면과 패시베이션 영향으로 기판의 소수 반송자 수명이 증가하며, 태양전지 제작시 접촉저항을 감소시켜 효율을 증가 시킬수 있다. HWO 공정은 반응조 안의 DI water 온도와 반응 시간에 따라 life-time을 측정하여 진행하였으며, 이후 PE-CVD법으로 증착된 a-Si:H layer 및 투명전도 산화막, 금속전극을 증착하여 실리콘 이종접합 태양전지를 제작하였다.

• Korean Journal of Materials Research
• /
• v.8 no.10
• /
• pp.890-897
• /
• 1998

The direct wafer bonding between n-InP(001) wafer and the ${Si}_3N_4$(200 nm) film grown on the InP wafer by PECVD method was investigated. The surface states of InP wafer and ${Si}_3N_4$/InP which strongly depend upon the direct wafer bonding strength between them when they are brought into contact, were characterized by the contact angle measurement technique and atomic force microscopy. When InP wafer was etched by $50{\%}$ HF, contact angle was $5^{\circ}$ and RMS roughness was $1.54{\AA}$. When ${Si}_3N_4$ was etched by ammonia solution, RMS roughness was $3.11{\AA}$. The considerable amount of initial bonding strength between InP wafer and ${Si}_3N_4$/InP was observed when the two wafer was contacted after the etching process by $50{\%}$ HF and ammonia solution respectively. The bonded specimen was heat treated in $H^2$ or $N^2$, ambient at the temperature of $580^{\circ}C$-$680^{\circ}C$ for lhr. The bonding state was confirmed by SAT(Scannig Acoustic Tomography). The bonding strength was measured by shear force measurement of ${Si}_3N_4$/InP to InP wafer increased up to the same level of PECVD interface. The direct wafer bonding interface and ${Si}_3N_4$/InP PECVD interface were chracterized by TEM and AES.

• Korean Journal of Plant Taxonomy
• /
• v.41 no.4
• /
• pp.370-382
• /
• 2011

We investigated the area around four moors from May 2009 to June 2010 for plant diversity in Moojechineup, officially designated as the Ramsar wetland. The vascular plants of Moojechineup at Mt. Jeongjok were recorded as total 149 taxa, 55 families, 105 genera, 128 species, 1 subspecies, 16 varieties, and 4 forms. Rare plants were observed 7 taxa (Eriophorum gracile Koch, Drosera rotundifolia L., Iris ensata var. spontanea (Makino) Nakai, Kobresia bellardii (All.) Degl, Utricularia bifida L., Utricularia racemosa Wall., Utricularia yakusimensis Masam.). Korean endemic plants were 1 taxon, floristics special plants were 19 taxa, and naturalized plants were 3 taxa. Phytogeographical and evolutionarily, Eriophorum gracile is an important species; hence, further studies are needed to conserve it. Moojechineup is similar to the Shinbulsan wetland in terms of wetland plants (hydrophytes). Moojechineup's flora changes are in process slowly compared to earlier work; thus, continuing interest and appropriate measures should be encouraged.

• The Journal of the Petrological Society of Korea
• /
• v.9 no.3
• /
• pp.142-168
• /
• 2000

The granites distributed in the Kyongsang basin contain the rocks which are different from the host rocks, and they are known as magic microgranular enclaves. The genesis of the magic micro-granular enclaves can be divided into four types: (1) rock fragments from country rocks; (2) cumulation of the early crystals in host magma or disruption of early chilled borders; (3) magma mingling; and (4) restite. These enclaves can be easily found in the granites around Mt. Wonhyo, Yangsan city. They are ellipsoidal in shape, and have phenocrysts might be originated from the host rocks and sharp contacts with the granites. Under the microscope, textures such as oscillation zoning, horn-blende-mantled quartz, rapakivi texture, and acicular apatite are observed, and these indicate that the enclaves were originated from magma and then produced by chilling. The evidences showing that the enclaves were formed by magma mingling are: (1) petrographical characteristics; (2) similarity of the compositions between the rim of plagioclase in the enclave and plagioclase in the granite; (3) linear trends of the major elements; (4) total REE content of the enclaves; and (5) Textural and compositional variations from rim to core in zoned enclaves. The magic end member of the enclave is regarded as the aphyric basaltic andesite in Mt. Sinbul-Youngchui area. The granites around Mt. Wonhyo experienced the magma mingling process which was produced by the injection of mafic magma at about 70 Ma, during the crystal differentiation, and then continued the crystallization. The equigranular granites and the micrographic granites in the study area are considered as the results after the magma mingling process.

• Parasites, Hosts and Diseases
• /
• v.26 no.4
• /
• pp.263-274
• /
• 1988

Recent patterns of infection with digenetic larval trematodes in fresh- water and brackish-water ask were studied in three locations of the river Taewha during the period from April to October, 1988, and compared with the data reported previously in the same river, 0(16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh.water fish. The metacercariae of Echinochasmus sp. , Metacercaria hasegawai and Metagonimus yokogawai were found from 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, whereas their intensity of infection was found lowered in 3 species, Ccreobagrus brevicorpus, Gnathopogon atromaculatus, and Funtungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Flecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. The encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh- water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.

• Journal of the Korean Institute of Gas
• /
• v.22 no.5
• /
• pp.1-17
• /
• 2018

Related incidents and accidents are frequent after 2000 years, such as the outbreak of the Taian peninsula crude oil spillage and Gumi hydrofluoric acid leakage accident. In the wake of such environmental pollution accidents, Consensus has been formed to enact legislation on liability for the compensation of environmental pollution in 2014 and the rescue, and has been in force since January 2016. Therefore, in the domestic insurance industry, the introduced environmental liability insurance system needs to be managed through the standardization formula of a new insurance model for managing the environmental risk. This study has been carried out by the emergence of a safe insurance model with a risky nature of the risk type, which is one of the services of the knowledge base. The verification of the six assurance media on the occurrence of environmental pollution such as chemical, waste, marine, soil, etc. is expressed through semantic interoperability through this possible ontology. The insurance model was designed and presented by deducing the relationship between the amount of money and the amount of money that was written in the area of existing expertise, In order to exclude the possible consequences, the concept of abstract is conceptualized in the form of a customer, and a plan for the future development of an ontology-based decision support system is proposed to reduce the cost and resources consumed every year. It is expected that standardization of the verification standard of the mass of mass will minimize errors and reduce the time and resources required for verification.

• Journal of Wetlands Research
• /
• v.9 no.3
• /
• pp.1-12
• /
• 2007

In this study, the correlation of organic content with particle size and type of sediment was found out.Particle size, stratigraphic section and organic content of sediments sampled from Dalpo wetland was analyzed. Dalpo wetland consists of three wetlands, and the area of Dalpo wetland is about $31,295m^2$. The particle size analyses for sampled sediments of 7 points (3 points in wetland A, 3 points in wetland B and 1 point in wetland C) were tested. As results of the particle size analyses, the sediment particle size becomes larger as to the edge of the wetland. It is revealed in order of wetland A > wetland C > wetland B. Borehole surveys with horizontal distance in the major and minor axes of wetland A, the major and minor axes of wetland B and the major axis of wetland C were accomplished. Clayey peat deposit is distributed at 10~90 cm depth below ground surface in the major axis of wetland A. The clayey peat deposit was the most thick at the center of wetland A that horizontal distance is 100 m. As the depth below ground surface of clayey peat deposit is less than 27 cm in the wetland B, we can infer that the life for the wetland B is being finished. Sediment composition of wetland C is simple because wetland C is small scale, and clayey peat deposit is distributed at 10~34 cm depth below ground surface. Sediment sampled by borehole survey in the Dalpo wetland was cut at interval of 10 cm, then organic content was analyzed. Organic content of wetland A sediment showed more than 40% until 70 cm depth below ground surface, also sediment of wetland B is similar to wetland A until 10 cm depth below ground surface, but is showed within 20 % above 30 cm depth below ground surface. Organic content of wetland B is showed the lowest as organic content near the ground surface is about 40%. All of the three wetlands, organic content is showed higher at clayey peat deposit near to ground surface. This is caused by finer particles of the clayey peat deposit, also organic materials were supplied from dead vegetation. Organic content of the Dalpo wetland showed in order of wetland A > wetland C > wetland B. This result is caused by thickness of clayey peat deposit in sediment. Through this study, it was verified that organic content of the Dalpo wetland sediment was dominated by particle size of sediment and vegetation of the upper part.