• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E2
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• pp.35-42
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• 2001

Recent development of photocatalytic degradation method that is mediated by TiO$_2$ is of interest in the treatment of volatile organic compounds(VOCs). In this study, trichloroethylene(TCE) and acetone were closely examined in a batch scale of photo-reactor as a function of water vapor, oxygen, and temperature. Water vapor inhibited the photocatalytic degradation of acetone, while there was an optimum concentration in TCE. A lower efficiency was found in nitrogen atmosphere than air, and the effect of oxygen on photocatalytic degradation of acetone was greater than on that of TCE. The optimum reaction temperature on photocatalytic degradation was about 45$^{\circ}C$ for both compounds. NO organic byproducts were detected for both compounds under the present experimental conditions. It was ascertained that the photocatalytic reaction in a batch scale of photo-reactor was very effective in removing VOCs such as TCE and acetone in the gaseous phase.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.71-81
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• 1996

Direct Sky Blue-5B is an Azo dye known as general for staining of textile and leather, etc., and as materials which are difficult to be biodegraded in nature. The bacterium strain which could degrade direct Sky Blue-5B was isolated from activated sludge of dyeing factory and identified as Proteus sp. by experiment on morphological, cultural and biochemical characteristics, and so named Proteus sp. ST-1. The optimum condition of the strain for degradation of Sky Blue-5B were at about 35$^{\circ}C$ and PH 7~8. The strain had been capable of degradation with organic nitrogen effectively and had completely degraded 200mg/1 of the dye within 12hrs at 37$^{\circ}C$. The enzyme system related to degradation of Azo dye may be intracellular, and so degraded the dye after absorption into cell. The degradation products of Sky Blue-5B by Proton sp. 57-1 were analyzed by Gas Chromatography /Mass Spectrometry and Spectrophotomer, from this observation, it may be infered that the strain degraded the dye directly without any mediate.

• Korean Journal of Remote Sensing
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• v.39 no.4
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• pp.395-407
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• 2023

Super-resolution (SR) has great significance in image processing because it enables downstream vision tasks with high spatial resolution. Recently, SR studies have adopted deep learning networks and achieved remarkable SR performance compared to conventional example-based methods. Deep-learning-based SR models generally require low-resolution (LR) images and the corresponding high-resolution (HR) images as training dataset. Due to the difficulties in obtaining real-world LR-HR datasets, most SR models have used only HR images and generated LR images with predefined degradation such as bicubic downsampling. However, SR models trained on simple image degradation do not reflect the properties of the images and often result in deteriorated SR qualities when applied to real-world images. In this study, we propose an image degradation model for HR satellite images based on the modulation transfer function (MTF) of an imaging sensor. Because the proposed method determines the image degradation based on the sensor properties, it is more suitable for training SR models on remote sensing images. Experimental results on HR satellite image datasets demonstrated the effectiveness of applying MTF-based filters to construct a more realistic LR-HR training dataset.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.810-816
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• 2012

In order to develop liquid fertilizer using rendering by-product, rates and velocities of degradation from rendering by-product using pig cadaver investigated under different amount of injection and time with degradation agents (KOH, NaOH, $HNO_3$ and $H_2SO_4$). The amount of residue by degradation agent of $HNO_3$ treatment method was higher than that in KOH, NaOH and $H_2SO_4$ treatment methods. The degradation velocities (K; $hr^{-1}$) of rendering by-product in KOH treatment method were higher in the order of 25% ($0.0309hr^{-1}$) > 30% ($0.0268hr^{-1}$) > 20% ($0.0142hr^{-1}$) > 15% ($0.0111hr^{-1}$) > 10% ($0.0102hr^{-1}$) of weight of rendering by-product. In all conditions, the degradation velocity of rendering by-product using $H_2SO_4$ 30% of weight of rendering by-product was rapid than that for KOH, NaOH and $HNO_3$ treatment methods. Degradation rates of rendering by-product using NaOH were similar to that of KOH and $H_2SO_4$ except for $HNO_3$ under injecting 25% and 30% of rendering by-product weight.

• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.105-115
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• 1996

In this paper, we reviewed the degradation factors of diazinon which was known to be easily degraded by soil microorganisms and lost of its activity. Under submerged soil condition, the contribution of microorganisms to diazinon degradation was about 40% and these microorganisms preferred soil humus as substrates to diazinon itself. The effect of monooxygenase activity in submerged soil was more important than esterase activity on diazinon degradation and these enzymes were inhibited by several chemicals such as piperonyl butoxide(PBO), EPN and tricyclazole. From these results, new formulation type of diazinon (PBO and triphenyl phosphate were added to commercial diazinon formulation by 0.1% respectively.) and diazinon mixture formulation (diazinon was mixed with EPN, tricyclazole and carbofuran in equal amount) were prepared. The new formulation type of diazinon showed better insecticidal activity by 12% and more delayed diazinon degradation in ten days than commercial diazinon.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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• pp.24-30
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• 1999

A biological filter for treatment of toluene among volatile organic compounds was studied. The investigation was conducted using specially built stainless steel columns packed with granular activated carbon and cold for removal of toluene. The G.A. and mold as filter material was also coated with Pseudomonas putida microorganisms.The biofilter unit was operated in the condition of moisture content vairation at gas loading rate of 12.5 l/min. Gaseous toluene taken from tedlar bag was analyzed by the use of G.C equipped with F.I.d detector. The removal efficiency of gaseous toluene was 95% at average inlet concentration of 950 ppm during bio-degradation operating condition. Effective removal efficiency was obtained with moisture content 27.5% at activated carbon and 32% at mold in this study. The effective operating condition were obtained with pH 6-8, temperature 28-42℃ for microbial degradation at gas loading rate of 12.5 l/min in packed material.

• Journal of Environmental Science International
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• v.11 no.9
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• pp.987-992
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• 2002

Nanosized titania sol has been produced by the controlled hydrolysis of titanium tetraisopropoxide(TTIP) in sodium bis(2-ethylhexyl)sulfosuccinate(AOT) reverse micelles. The physical properties, such as crystallite size and crystallinity according to R ratio have been investigated by FT-IR, XRD and UV-DRS. In addition, the photocatalytic degradation of bromate has been studied by using batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. It is shown that the anatase structure appears in the 300~$600^{\circ}C$ calcination temperature range and the formation of anatase into rutile starts above $700^{\circ}C$. The crystallite size increases with increasing R ratio. In the photocatalytic degradation of bromate, the photocatalytic decomposition of bromate shows the decomposition rate increases with decreasing initial concentration of bromate and with increasing intensity of light.

• Journal of Environmental Science International
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• v.26 no.1
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• pp.1-10
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• 2017

In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene oxide (GO) nanocomposite films containing various content of GO were prepared using solution casting method. The effect of GO content on Young's modulus and dispersion of GO in PHBV matrix was investigated. Also, the thermomechanical properties, oxygen transmission rates and hydrolytic degradation of PHBV/GO nanocomposite films were studied. The addition of GO into PHBV improves the Young's modulus and decreases thermal expansion coefficient. The improvement can be mainly attributed to good dispersion of GO and interfacial interactions between PHBV and GO. Furthermore, PHBV/GO nanocomposite films show good oxygen barrier properties. PHBV/GO nanocomposites show lower hydrolytic degradation rates with increasing content of GO.

• Journal of the Korean Graphic Arts Communication Society
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• v.29 no.3
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• pp.97-104
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• 2011

The storing ability of information of optical disks directly depends on the physical property of recording unit cells. It means that the degradation of optical disks ultimately causes the loss of the physical and chemical properties of recording unit cells and leads also information, too. We investigated the degradation and life time of optical disks which tell us the longevity of the preservation of information. Optical disks were aged using the accelerated aging system and studied by optical reflectivity spectroscopy and atomic force microscopy(AFM), and the preservation environment of electronic media in National central library of Korea also were analysed. Results show that the double reflective coated optical disks have good preservation of recording information but revealed some deformation of dye area in the AFM images. It means that we should include the mechanical and chemical degradation of the optical disks in the life time expectation evaluation.

• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.161-166
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• 2004

The impact of dissolved wastewater constituents on the treatment of synthetic bisphenol A (BPA) solutions was investigated under a variety of reaction conditions. The laccase enzyme from Trametes vesicolor was used for the BPA treatment. The constituents studied included various inorganic salts, organic compounds and heavy metal ions. BPA degradation was inhibited by sulfate, thiosulfate, sulfide, nitrite, and cyanide ions at 25 mg/$\ell$, 100mg/$\ell$, 25 mg/$\ell$ 150 mg/$\ell$, and 2.5 mg/$\ell$, respectively. However, the inhibitive effects of sulfide and sulfite on BPA degradation were diminished by additional aeration to oxidize them. Formaldehyde significantly reduced the rate of BPA degradation at 1.0% among organic compounds studied. Among heavy metal ions tested, Fe(II) substantially suppressed BPA removal at 1 mM. MgCl$_2$ and CaCl$_2$ exhibited great inhibition of BPA degradation at 25mM.