• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.188-193
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• 2010

The aim of this study is to evaluate the effects of organic materials on soil organisms. Changes in the community structure, and population density of soil organisms (microbes, nematodes, and microarthropods) were studied in a Korean ginseng field. Phospholipid fatty acids analysis showed that the relative abundances of bacteria, fungi, and actinomycetes did not differ significantly. The aerobes/anaerobes ratio was the lowest in soils amended with leaf mold, indicating that the decomposition speed was slow. Further, the addition of leaf mold to the soil enhanced the saturated/monounsaturated fatty acid ratio and cyclopropyl fatty acid/precursor ratio, which indicated an increase in environmental stresses. Application of pig manure compost (PMC) had positive effects on the population density of nematodes, and negative effects on that of oribatid mites. The population densities of nematodes, and microarthropods remained relatively low in the plots that had been treated with leaf mold or pig manure compost. It is suggested that pre-planting soil management directed at enhancing the biological decomposition efficiency should be continued over a long period to increase the soil bioactivity in virgin soils.

• Korean Chemical Engineering Research
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• v.48 no.1
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• pp.75-79
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• 2010

The precursor powders with thin wall structure were prepared by spray pyrolysis from the spray solution with ethylenediaminetetraacetic acid, citric acid and $NH_4Cl$ flux. The $BaMgAl_{10}O_{17}:Eu$ phosphor powders formed from the spray solution without organic additives and flux material had sizes of $1{\sim}5{\mu}m$ and hollow structure with high thickness at post-treatment temperature of $1,200^{\circ}C$. However, $BaMgAl_{10}O_{17}:Eu$ phosphor powders formed from the spray solution with ethylenediaminetetraacetic acid, citric acid and $NH_4Cl$ flux had fine size and plate-like shape. The mean crystallite sizes of the phosphor powders with fine sizes were 23, 35, and 33 nm when the content of $NH_4Cl$ flux were 0, 6, 35 wt% of phosphor. The photoluminescence intensity of the phosphor powders formed from the spray solution with the optimum amount of $NH_4Cl$ flux as 35 wt% was 215% of that of the phosphor powders formed from the spray solution without flux material.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.377-377
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• 2012

Microprocessor technology now relies on copper for most of its electrical interconnections. Because of the high diffusivity of copper, Atomic layer deposition (ALD) $TaN_x$ is used as a diffusion barrier to prevent copper diffusion into the Si or $SiO_2$. Another problem with copper is that it has weak adhesion to most materials. Strong adhesion to copper is an essential characteristic for the new barrier layer because copper films prepared by electroplating peel off easily in the damascene process. Thus adhesion-enhancing layer of cobalt is placed between the $TaN_x$ and the copper. Because, cobalt has strong adhesion to the copper layer and possible seedless electro-plating of copper. Until now, metal film has generally been deposited by physical vapor deposition. However, one draw-back of this method is poor step coverage in applications of ultralarge-scale integration metallization technology. Metal organic chemical vapor deposition (MOCVD) is a good approach to address this problem. In addition, the MOCVD method has several advantages, such as conformal coverage, uniform deposition over large substrate areas and less substrate damage. For this reasons, cobalt films have been studied using MOCVD and various metal-organic precursors. In this study, we used $C_{12}H_{10}O_6(Co)_2$ (dicobalt hexacarbonyl tert-butylacetylene, CCTBA) as a cobalt precursor because of its high vapor pressure and volatility, a liquid state and its excellent thermal stability under normal conditions. Furthermore, the cobalt film was also deposited at various $H_2/NH_3$ gas ratio(1, 1:1,2,6,8) producing pure cobalt thin films with excellent conformality. Compared to MOCVD cobalt using $H_2$ gas as a reactant, the cobalt thin film deposited by MOCVD using $H_2$ with $NH_3$ showed a low roughness, a low resistivity, and a low carbon impurity. It was found that Co/$TaN_x$ film can achieve a low resistivity of $90{\mu}{\Omega}-cm$, a low root-mean-square roughness of 0.97 nm at a growth temperature of $150^{\circ}C$ and a low carbon impurity of 4~6% carbon concentration.

• Clean Technology
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• v.6 no.2
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• pp.121-127
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• 2000

There are several kinds of hazardous materials in incinerator flue gas, such as particulate matter, acid gas, heavy metal, dioxin, etc. The activated carbon adsorption is considered as one of the methods removing dioxin from flue gas. Without any additional equipment and facilities, the activated carbon was mixed with lime and sprayed in the semi-drying reactor of an incinerator and filtered in the bag filter, and its efficiency of removing hazardous organic material was investigated. 1,2-dichlorobenzene (o-DCB) was used as a precursor material of dioxin and the effects of the activated carbon amount, the operating temperature of the reactor, and the atomizer r.p.m were measured and analyzed. Experimental results showed that the optimum outlet temperature of the reactor was $145^{\circ}C$ considering the performance of the bag filter, and the adsorption performance improved with the increase of the atomizer r.p.m. Also the performance of removing o-DCB in the bag filter is higher than of the semi-drying reactor.

• Clean Technology
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• v.6 no.2
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• pp.113-119
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• 2000

Due to the toxicity of dioxin in the incinerator flue gas, it becomes a severe social problem. Activated carbon adsorption process is one of the methods for removing dioxin in the flue gas and was investigated its performance for removing hazardous organic compounds. Since dioxin is very hazardous material, 1,2-dichlorobenzene(o-DCB), one of the precursor material of dioxin, was used as adsorbate. The effects of air flow rate, pressure drop in the bag filter, operation temperature of bag filter, and kinds of adsorbents on the removal of o-DCB were measured and analysed. Experimental results showed that the operating temperature was recommended within the range of $140{\sim}170^{\circ}C$ considering the operating condition of incinerator. Also it was necessary to maintain the pressure drop of bag filter $120mmH_2O$ for enhancing the adsorption at the surface layer of activated carbon formed on the bag filter. The use of mixture of same amount of activated carbon and diatomite showed more than 90% removal of o-DCB and also reduced the consumption of activated carbon.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.407-411
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• 2005

YAG:Tb($Y_3Al_5O_{12}:Tb$) phosphor particles were prepared by spray pyrolysis from spray solution containing various types of flux materials. The effects of type of flux, organic material and post-treatment temperature on the characteristics of morphology, crystallinity and photoluminescence of YAG:Tb phosphor particles were investigated. Citric acid and ethylene glycol used as organic additive improved the photoluminescence intensity of the YAG:Tb phosphor particles without destruction of the morphology after post-treatment at high temperature. However, the spherical shape of the precursor particles obtained by spray pyrolysis from spray solution containing high amount of flux material disappeared after post-treatment at $1300^{\circ}C$. YAG:Tb phosphor particles prepared from spray solution containing lithium carbonate flux had fine size and regular morphology after post-treatment. Lithium carbonate used as flux material was also efficient in improvement of the photoluminescence intensity of the YAG:Tb phosphor particles. The optimum photoluminescence intensity of the YAG:Tb phosphor particles prepared from spray solution containing lithium carbonate flux was 189％ of that of the phosphor particles prepared from spray solution without flux material.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.77-77
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• 2000

Titanium oxide (TiO2) thin films have valuable properties such as a high refractive index, excellent transmittance in the visible and near-IR frequency, and high chemical stability. Therefore it is extensively used in anti-reflection coating, sensor, and photocatalysis as electrical and optical applications. Specially, TiO2 have a high dielectric constant of 180 along the c axis and 90 along the a axis, so it is highlighted in fabricating dielectric capacitors in micro electronic devices. A variety of methods have been used to produce patterned self-assembled monolayers (SAMs), including microcontact printing ($\mu$CP), UV-photolithotgraphy, e-beam lithography, scanned-probe based micro-machining, and atom-lithography. Above all, thin film fabrication on $\mu$CP modified surface is a potentially low-cost, high-throughput method, because it does not require expensive photolithographic equipment, and it produce micrometer scale patterns in thin film materials. The patterned SAMs were used as thin resists, to transfer patterns onto thin films either by chemical etching or by selective deposition. In this study, we deposited TiO2 thin films on Si (1000 substrateds using titanium (IV) isopropoxide ([Ti(O(C3H7)4)] ; TIP as a single molecular precursor at deposition temperature in the range of 300-$700^{\circ}C$ without any carrier and bubbler gas. Crack-free, highly oriented TiO2 polycrystalline thin films with anatase phase and stoichimetric ratio of Ti and O were successfully deposited on Si(100) at temperature as low as 50$0^{\circ}C$. XRD and TED data showed that below 50$0^{\circ}C$, the TiO2 thin films were dominantly grown on Si(100) surfaces in the [211] direction, whereas with increasing the deposition temperature to $700^{\circ}C$, the main films growth direction was changed to be [200]. Two distinct growth behaviors were observed from the Arhenius plots. In addition to deposition of THe TiO2 thin films on Si(100) substrates, patterning of TiO2 thin films was also performed at grown temperature in the range of 300-50$0^{\circ}C$ by MOCVD onto the Si(100) substrates of which surface was modified by organic thin film template. The organic thin film of SAm is obtained by the $\mu$CP method. Alpha-step profile and optical microscope images showed that the boundaries between SAMs areas and selectively deposited TiO2 thin film areas are very definite and sharp. Capacitance - Voltage measurements made on TiO2 films gave a dielectric constant of 29, suggesting a possibility of electronic material applications.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.5-13
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• 2021

Ammonia, primarily originating from urinary urea of the livestock manure, is known to play as a major precursor of fine particulate matter (PM2.5) generation which leads to a decrease in air quality and to harmful effects on public health. The objective of this study was to evaluate the effect of acetohydroxamic acid (AHA) addition on inhibition of ammonia conversion from urea. The experiment was performed at different urea concentration (500-4,000 mg Urea-N/L), AHA concentration (0-4,000 mg AHA/L), pHs (pH 6-10), and temperature (10-35℃). The result showed that the urease inhibition efficiency increased at higher concentration of AHA. However, the specific urease inhibition activity decreased at higher pH, showing 867.1±6.7 Unit/g AHA at pH 6 and 1,167.9±17.4 Unit/g AHA at pH 10, respectively. Decreased urease inhibition efficiency at both AHA and control was observed at higher temperature. This finding indicates that AHA can be used as the urease inhibitor for reducing ammonia emission in the management of livestock manure.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.27-34
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• 2023

In this study, various plant-based biomass are recycled into carbon materials to employ as anode materials for lithium-ion batteries. Firstly, various biomass of rice husk, chestnut, tea bag, and coffee ground are collected, washed, and ground. The carbonization process is followed under a nitrogen atmosphere at 850℃. The morphological and chemical properties of materials are investigated using FE-SEM, EDS, and FT-IR to compare the characteristic differences between various biomass. It is noticeable that biomass-derived carbon materials vary in shape and degree of carbonization depending on their precursor materials. These materials are applied as anode materials to measure the electrochemical performance. The specific capacities of rice husk-, chetnut-, tea bag-, and coffee ground-derived carbon materials are evaluated as 65.8, 80.2, 90.6, and 104.7 mAh g^-1 at 0.2C. Notably, coffee ground-based carbon exhibited the highest specific capacity owing to the difference in elemental composition and the degree of carbonization. Conclusively, this study suggests the possibility of utilizing as energy storage devices by employing various plant-based biomass into active materials for anodes.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.1
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• pp.21-29
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• 2024

In this study, EMC(Epoxy molding compound) waste from the semiconductor molding process is recycled and synthesized into silica nanoparticles, which are then applied as abrasive materials contains CMP(Chemical mechanical polishing) slurry. Specifically, silanol precursor is extracted from EMC waste according to the ultra-sonication method, which provides heat and energy, using ammonia solution as an etchant. By employing as-extracted silanol via a facile sol-gel process, uniform silica nanoparticles(e-SiO₂, experimentally synthesized SiO₂) with a size of ca. 100nm are successfully synthesized. Through physical and chemical analysis, it was confirmed that e-SiO₂ has similar properties compared to commercially available SiO₂(c-SiO₂, commercially SiO₂). For practical CMP applications, CMP slurry is prepared using e-SiO₂ as an abrasive and tested by polishing a semiconductor chip. As a result, the scratches that are roughly on the surface of the chip are successfully removed and turned into a smooth surface. Hence, the results present a recycling method of EMC waste into silica nanoparticles and the application to high-quality CMP slurry for the polishing process in semiconductor packaging.