• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 춘계학술대회 논문집
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• pp.339-340
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• 2008

• 한국표면공학회지
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• 제42권5호
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• pp.197-202
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• 2009

The electrodeposition in acidic aqueous electrolyte bath of cadmium telluride on gold electrodes has been studied by electrochemical analysis. Conventional cyclic voltammetry using potentiostat is considered as a reliable method to study electrochemical behavior of electrodeposition of CdTe. In this paper, the mechanism of CdTe deposition and its cyclic voltammetry were studied with the Te ion concentration, temperature, potential, and scan rate. We also investigated surface morphologies using FESEM and atomic composition of Cd and Te using EDS. Atomic composition of Cd and Te were varied with Te ion concentration in the electrolyte.

• 한국표면공학회지
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• 제44권4호
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• pp.137-143
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• 2011

The internal stress and magnetic properties (coercivity and squareness) of Ni-Fe nano thin film synthesized by electrodeposition method were studied as a function of acidic chloride bath conditions (composition and temperature) and current density. Fe deposition patterns were different depending on the temperature of the solution, the stress of film decreased with increasing the solution temperature, and the depending on the amount of Fe deposition showed a parabolic shape. The grain size of film was inversely proportional to stress of thin film. The internal stress of thin film and magnetic properties were deeply relevant, and the stress of thin film had a relationship with bath conditions and grain size of the thin film surface.

• 자원환경지질
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• 제20권1호
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• pp.1-18
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• 1987

The Cheolam silver deposits are emplaced along the fractures in breccia dike and the Hongjesa granite. Breccia dike contains fragments of late Cretaceous acidic volcanic rocks and other fragments of various rocks distributed in the mine area. Therefore it is presumed that the mineralization was taken place in later than late Cretaceous time. Mineral paragenesis is complicated by multiple episodes of fracturing. Six distinct depositional stages can be recognized: stage I, deposition of base metal sulfides; stage II, deposition of base metal sulfides and silver minerals; stage III, deposition of carbonates; stage IV, deposition of silver minerals and base metal sulfides; stage V, deposition of silver minerals; stage VI, deposition of barren quartz. Silver minerals from the deposits are native silver, acanthite, pyrargyrite, argentian tetrahedrite, stephanite, polybasite, pearceite, allargentum, antimonial silver and electrum. Fluid inclusion studies ware carried out for stage I, II, IV and VI quartz and stage III calcite. Homogenization temperatures for each stage are as follows: stage I, from $225^{\circ}$ to $360^{\circ}C$; stage II, from $145^{\circ}$ to $220^{\circ}C$; stage III, from $175^{\circ}$ to $240^{\circ}C$; stage IV, from $130^{\circ}$ to $185^{\circ}C$; stage VI, from $120^{\circ}$ to $145^{\circ}C$. Salinities of ore fluids were in the range of 4 and 10 wt.% equivalent NaCl over stage I and stage VI. Ore mineralogical data of each stage indicate that temperatures are within the range of homogenization temperature of fluid inclusions and sulfur fugacities declined steadily from $10^{-9.7}atm$. to $10^{-18.7}atm$. through stage I into stage V.

• Environmental Engineering Research
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• 제25권3호
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• pp.409-417
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• 2020

Investigation was carried out to assess the effect of cement dust deposition on the physico-chemical properties of soil near some cement plants in Jaintia Hills, Meghalaya. Soil samples were collected and analysed and compared with the control site. Comparison of various soil physico-chemical parameters revealed that cement dust emanating from cement plants has changed the soil quality in the surrounding areas of cement plants. The normal soil pH in the area is generally acidic. However, due to the continuous deposition of cement dust soil pH was found slightly alkaline near the cement plants. The higher values of soil parameters such as electrical conductivity and bulk density were also noticed near the cement plants. However, lower values of water holding capacity, soil moisture content, soil organic carbon and total nitrogen content were found compared to the control sites. The effect of cement dust deposition on soil is more in areas nearer to the cement plants. At present the changes may not be so serious but if this trend continues, soil properties of a vast area around the cement plants are likely to change leading to multiple effects on flora, fauna and socio-economy of the area.

• 한국재료학회지
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• 제20권1호
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• pp.12-18
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• 2010

$CuInSe_2$ (CIS) thin films were electrodeposited on Mo-coated glass substrates in acidic solutions containing $Cu^{2+}$, $In^{3+}$, and $Se^{4+}$ ions, depending on deposition parameters such as deposition potential (-0.4 to -0.8 V[SCE]) and pH (1.7 to 1.9). The influences of PH and deposition potential on the atomic composition of Cu, In, and Se in the deposited films were observed. The best chemical composition, approaching 1:1:2 atomic ratio for the elements, was achieved at -0.5 V (SCE) and pH 1.8. The as-deposited films showed low crystallinity and were annealed at 300 to $500^{\circ}C$ for 30 min to improve crystallization. The surface morphologies, microstructures, and crystallographic structures of the annealed films as well as the as-deposited films were analyzed with AFM, SEM, and XRD. The defects of spherical particles appeared on the surfaces of CIS thin films in the as-deposited state and decreased in size and number with increasing annealing temperatures. Additionally, the crystallization to chalcopyrite structure and surface roughness (Ra) of the as-deposited thin films were improved with the annealing process.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.280-284
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• 2004

Multicrystalline silicon wafers were textured in an alkaline bath, basically using sodium hydroxide and in acidic bath, using mainly hydrofluoric acid (HF), nitric acid $(HNO_3)$ and de-ionized water (DIW). Some wafers were also acid polished for the comparative study. Comparison of average reflectance of the samples treated with the new recipe of acidic solution showed average diffuse reflectance less than even 5 percent in the optimized condition. Solar cells were thus fabricated with the samples following the main steps such as phosphorus doping for emitter layer formation, silicon nitride deposition for anti-reflection coating by plasma enhanced chemical vapor deposition (PECVD) and front surface passivation, screen printing metallization, co-firing in rapid thermal processing (RTP) Furnace and laser edge isolation and confirmed >14 % conversion efficiency from the best textured samples. This isotropic texturing approach can be instrumental to achieve high efficiency in mass production using relatively low cost silicon wafers as starting material.

• 한국토양환경학회지
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• 제1권2호
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• pp.15-21
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• 1996

산성강하물이 단기간에 걸쳐 지표수의 산성화에 미치는 영향을 조사하기 위하여 1995년 5월부터 10월까지 외부오염원이 거의 없는 강원도 춘천시에 위치한 저수지를 선정하여 연구를 수행하였다. 연구지역 일대의 지질을 조사하고 산골짜기에서 저수지로 흐르는 작고 얕은 하천의 수질을 분석하였다. 강우량은 우량계를 이용하여 측정하였고 강하물은 자동포집기를 이용하여 포집하였다. 연구기간동안의 강우의 pH 범위는 3.81~5.77로 평균 4.8을 나타내었으며 전기전도도 (EC)는 5~1.89$\mu$S/cm로 평균 10.6$\mu$S/cm를 나타냈다. 음이온 중에서는 ${SO_4}^{2-}$의 강하량이 3,119.7 kg/$\textrm{km}^2$로 가장 많았고, 양이온 중에서는 $NH^{4+}$가 1,053.2 kg/$\textrm{km}^2$로 가장 많았다. 지표수의 pH는 중성 또는 약염기성으로 강우의 pH가 산성이었음에도 지표수의 산성화 현상은 관찰되지 않았다. 그러나 골짜기에서 흐르는 하천수를 측정할 때마다 측정지점의 고도가 낮아질 수록 pH 값은 증가하는 경향을 나타내어 물이 하류로 흘러가는 동안에 일어난 산성 또는 염기성물질로 인한 산염기반응의 영향을 보여주었다. 이 결과는 토양의 완충능력과 모암내에서의 중화능력을 각각 구별하여 조사할 필요성을 제시하였다.

• Corrosion Science and Technology
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• 제22권3호
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• pp.187-192
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• 2023

The use of biomass is increasing as a response to the convention on climate change. In Korea, a method applied to replace fossil fuels is using wood chips in a cogeneration plant. To remove air pollutants generated by burning wood chips, a selective denitrification facility (Selective catalytic reduction, SCR) is installed downstream. However, problems such as ash deposition and descaling of the equipment surface have been reported. The cause is thought to be unreacted ammonia slip caused by ammonia ions injected into the reducing agent and metal corrosion caused by an acidic environment. Element analysis confirmed that ash contained alkali metals and sulfur that could cause catalyst poisoning, leading to an increase in the size of ash particle and deposition. Measurement of the size of ash deposited inside the facility confirmed that the size of ash deposited on the catalyst was approximately three times larger than the size of generally formed ash. Therefore, it was concluded that a reduction in pore area of the catalyst by ash deposition on the surface of the catalyst could lead to a problem of increasing differential pressure in a denitrification facility.

• 한국재료학회지
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• 제24권3호
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• pp.140-144
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• 2014

The contact mechanism of devices is usually researched at electrode contacts. However, the contact between a dielectric and channel at the MOS structure is more important. The graphene was used as a channel material, and the thin film transistor with MOS structure was prepared to observe the contact mechanism. The graphene was obtained on Cu foil by the thermal decomposition method with $H_2$ and $CH_4$ mixed gases at an ambient annealing temperature of $1000^{\circ}C$ during the deposition for 30 min, and was then transferred onto a $SiO_2/Si$ substrate. The graphene was doped in a nitrogen acidic solution. The chemical properties of graphene were investigated to research the effect of nitric atoms doping. The sheet resistance of graphene decreased after nitrogen acidic doping, and the sheet resistance decreased with an increase in the doping times because of the increment of negative charge carriers. The nitric-atom-doped graphene showed the Ohmic contact at the curve of the drain current and drain voltage, in spite of the Schottky contact of grapnene without doping.