• 동굴
• /
• 제61호
• /
• pp.5-16
• /
• 2000

Recently many environmental researcher are concerned about the ecological environment and the issue of environmental pollution in cave. In this paper we discuss about air pollution, water pollution, state of water quality, ecological environment and situation of environmental public damage in cave The concerning of air pollution in cave is mainly to the type of secondary contamination, which much is developed in various fields recently. The natural water in the most of cave is no problems but ground water has slitting with natural water during much raining period. The state of water quality is gradually contaminated with artificial environmental pollution, that is, the contents of kinds of Aluminum, Nickel, Copper, Zinc and Calcium are higher than before. On the other hand it is very important things to keep the control of constant temperature, darkness and humidity in cave. The contamination by lamp flora and even black colored contamination are appeared nowadays. The ecological environment in cave destructed by growing of mi coorganism. In fact the internal of cave is shielded with the state of climate of cave external but the environment of internal cave is contaminated, because blowing from external climate state. In addition to environmental pollution caused by carbon dioxide and body temperature of tourists. By the way eco-examination of cave is black color public damage, green color one and white color one has been discovered, so we need to have the situation of demand of environmental reservation alternatives.

• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
• /
• pp.371-387
• /
• 1999

La2-xSrxCuO4 single-crystalline films were prepared on bulk single crystals of Zn-doped La2CuO4 as the substrates by LPE technique using tow deferent methods. When prepared using an alumina crucible in normal electrical furnace, the La2-xSrxCuO4 films were contaminated with less than 3 at% aluminum from the alumina crucibles. Aluminum contamination either reduced or completely destroyed the superconductivity of the La2-xSrxCuO4 films. For LPE growthby modified TSFZ method using an infrared heating furnace without crucibles, the La2-xSrxCuO4 films of x=0.11 showed superconducting with Tconset 36 K, which is 10 K higher than that in the La2-xSrxCuO4 bulk single crystals.

• 한국수소및신에너지학회논문집
• /
• 제20권1호
• /
• pp.1-8
• /
• 2009

Hydrogen production by the reaction of aluminum alloys and NaOH solution was studied for an automotive proton exchange membrane fuel cell(PEMFC) application. In our experiment conditions($30{\sim}75^{\circ}C$, NaOH $0.5{\sim}5M$), passivation of aluminum was not occurred. Higher rate of hydrogen production was observed at the reaction with Al alloys that contain impurities. With an increase in reaction temperature, hydrogen production rate by an increase in NaOH concentration increased much. When hydrogen was fed into the anode without filtering, PEMFC cell performance decreased 35% by ionic contamination such as $Na^+$ on the membrane and electrode. Thus, filtering of produced hydrogen is necessary for PEMFC operation.

• 한국결정성장학회지
• /
• 제6권3호
• /
• pp.309-317
• /
• 1996

Al2O3 thin films were deposited on Si-wafer (100) using organo-aluminum compounds at low pressure by chemical vapor deposition (CVD) method. The vapor of the organo-metallic precursor was carried by pure N2 gas. The deposition rate increased and then saturated as Tsub increased with increasing the AIP flow rate. The main contamination didn't found in deposited films except carbon. The H-O(H2O) IR absorption band decreased in intensity as the deposition temperature increased, and completely disappeared through annealing.

• 한국토양환경학회지
• /
• 제2권3호
• /
• pp.31-38
• /
• 1997

산성폐수에 함유된 오염물질의 물리적 화학적 특성이 배우 복잡하기 때문에 산성폐수에 의해 오염된 지표수나 지하수등의 오염정도를 지역적, 시간적 변화에 따라 비교하는 일은 쉽지가 않다. 본 논문에서는 산성폐수에 의해 오염된 지표수나 지하수의 오염도를 정량적으로 평가할 수 있는 수학적 지표를 제시하였으며, 오염지표를 이용하여 국내 폐탄광의 갱내 유출수에 대한 오염도를 검토하였다. 사용된 오염지표(Acid Mine Drainage Index)는 수질의 오염정도를 가장 잘 나타낼수 있는 7개의 변수 즉, pH값, 황산염(Sulfate), 철, 망간, 알루미늄, 구리 및 아연 함량을 이용하여 계산하였다. 사용된 변수는 오염도에 미치는 상대적인 중요도를 감안하여 가중치를 사용하였으며 , pH값 및 황산염함량에 가장 높은 가중치를 부여하였다. 국내 폐광산에서 유출되는 산성폐수의 오염도 평가결과 경북 문경에 소재한 석봉탄광이 조사탄광중 상대적으로 오염도가 높았으며, 지역적으로 영동지역에 위치한 폐탄광의 갱내 유출수가 영서, 중부, 서부 및 남부에 위치한 폐탄광에 비해 오염도가 높게 나타났다.

• Journal of Radiation Protection and Research
• /
• 제9권2호
• /
• pp.112-117
• /
• 1984

A lot of radioisotopes are applied to medical fields. It's very important to measure the activities on airborne radioiodine discharged in air from $Na^{131}I$ solutions and from patients treated with radioiodine. Also surface decontamination is another one important problem to be completly solved in the isotope laboratory where there is always the possibility of radiation contamination. The Authors measured the activities on airborne radioiodine with RI collector and scintillation counter. 1. The mean accumulative activity of airborne radioiodine discharged into air from $Na^{131}I$ solution was measured as $1.3{\times}10^{-3}/hr$ rate, and the maximum value was $1.8{\times}10^{-3}/hr$. 2. Radioactivity rate per hour of airborne iodine discharged into air from patients treated with $Na^{131}I$ was measured as $6.2{\times}10^{-5}/hr$ at 8 hour after administration of radioiodine and decreased into $2{\times}10^{-6}/hr$ after 24 hour. 3. Metalic surfaces such as stainless steel or aluminum are decontaminated 5 to 6 times more rapidly than wood and concrete surfaces. 4. Decontamination with wet wiping with detergent was 9 to 10 times more rapidly than dry wiping method, but dry wiping was useful for the first step to prevent spreading and flowing from liquid radioactive materials.

• 한국광물학회지
• /
• 제31권2호
• /
• pp.75-86
• /
• 2018

본 연구는 강원도 도계광업소 수계에 발생한 적갈색침전물을 대상으로 침전환경을 파악하고, 중금속함량, 광물조성 및 그에 따른 분광학적 특성을 분석하였다. 적갈색침전물의 pH 범위는 7.59-7.94로 침전환경은 중성에 해당한다. X선형광분석 결과 철이 평균농도보다 높게 검출되었으며, 니켈, 구리 및 아연의 오염도가 높은 것으로 판명된다. X선회절분석 결과 돌로마이트, 방해석, 침철석, 자철석, 고령토, 엽납석, 석영 및 알루미늄 이소프로폭사이드의 광물이 확인되었다. 중금속 오염에 따른 분광학적 특성을 분석한 결과, 중금속함량이 증가함에 따라 가시광선 영역에서는 반사도가 증가하는 추세를, 적외선 영역에서는 반사도가 감소하는 추세를 보인다. 적갈색침전물의 분광특성은 침철석, 자철석, 고령토, 엽납석 및 알루미늄 이소프로폭사이드에 의해 발현되는 것으로 판단된다.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 추계학술발표대회
• /
• pp.44.2-44.2
• /
• 2009

Polycrystalline materials suchas yttria and alumina have been applied as a plasma resisting material for the plasma processing chamber. However, polycrystal line material may easily generate particles and the particles are sources of contamination during the plasma enhanced process. Amorphous material can be suitable to prevent particle generation due to absence of grain-boundaries. We manufactured nitrogen-containing $SiO_2-Al_2O_3-Y_2O_3$ based glasses with various contents of silicon and fixed nitrogen content. The thermal properties, mechanical properties and plasma etching rate were evaluated and compared for the different composition samples. The plasma etching behavior was estimated using XPS with depth profiling. From the result, the plasma etching rate highly depends on the silicon content and it may results from very low volatile temperature of SiF4 generated during plasma etching. The silicon concentration at the plasma etched surface was very low besides the concentration of yttrium and aluminum was relatively high than that of silicon due to high volatile temperature of fluorine compounds which consisted with aluminum and yttrium. Therefore, we conclude that the samples having low silicon content should be considered to obtain low plasma etching rate for the plasma resisting material.

• 한국결정성장학회지
• /
• 제9권3호
• /
• pp.299-302
• /
• 1999

$La_{2-x}Sr_{x}CuO_{4}$ single-crystalline films were prepared on bulk single crystals of Zn-doped $La_{2-x}Sr_{x}CuO_{4}$ as the substrates by LPE technique using two deferent methods. When prepared using an alumina crucible in normal electrical furnace, the $La_{2-x}Sr_{x}CuO_{4}$ films were contaminated with less than 3 at% aluminum from the alumina crucibles. Aluminum contamination either reduced or completely destroyed the superconductivity of the $La_{2-x}Sr_{x}CuO_{4}$ films, For LPE growth by modified TSFZ method using an infrared heating furnace without crucibles, the $La_{2-x}Sr_{x}CuO_{4}$ films of x=0.11 showed superconducting with $Tc_{onset}=36\;K$, which is 10 K higher than that in the $La_{2-x}Sr_{x}CuO_{4}$ bulk single crystals.

• Bulletin of the Korean Chemical Society
• /
• 제15권1호
• /
• pp.79-83
• /
• 1994

The organometallic chemical vapor deposition of single precursors, $[Me_2Al({\mu}-NHR)]_2\;(R=^iPr,\;^tBu)$, for alumininum nitride thin films has been investigated to evaluate their poroperties as potential precursors. In chemical vapor deposition processes the gas phase products scattered from a Ni(100) substrate were analyzed by mass spectrometry and the deposited films were characterized by X-ray photoelectron spectroscopy (XPS). The optimum temperatures for the formation of AlN films have been found to be between 700 K and 800 K. Carbon contamination of the films seems to be attributed mainly to the methyl groups bonded to the aluminum atoms. It is apparent that $^tBu$ group is better than $^iPr$ group as a substituent on the nitrogen atom of the single precursors for the AlN thin film formation.