• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.376-381
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• 2004

The use of electron beam irradiation was investigated to disinfect total coliforms in the secondary sewage treatment effluent. Unchlorinated secondary effluent was irradiated at different dose of 0.2~1.0 kGy by 1 MeV, ELV-4 Model electron beam accelerator. It is interesting to note that a 100 % reduction in total coliforms and total colonies were achieved until a dose of approximately 0.8 kGy. Even at low dose of 0.2 kGy, the total coliforms and total colonies were successfully inactivated to the level of satisfying the new effluent discharge guideline. Besides disinfection of total coliforms, approximately a 50% removal in biochemical oxygen demand was pronounced at a dose of 0.2 kGy. More than 20 % removal in suspended solids and turbidity was also observed at a dose of 1.0 kGy. The application of electron beam irradiation appeared to be one of options to reuse sewage treatment effluent as agricultural or industrial water.

• International journal of advanced smart convergence
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• v.9 no.4
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• pp.16-25
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• 2020

The operation of a wastewater treatment plant (WWTP) is a complex task which requires to consider several aspects: adapting to always changing influent composition and volume, ensuring treated effluents quality complies with local regulations, ensuring dissolved oxygen levels in biological reaction tanks are sufficient to avoid anoxic conditions etc. all of it while minimizing usage of chemicals and power consumption. The traditional way of managing WWTPs consists in having employees on the field measure various parameters and make decisions based on their judgment and experience which holds various concerns such as the low frequency of data, errors in measurement and difficulty to analyze historical data to propose optimal solutions. In the case of activated sludge WWTPs, parts of the treatment process can be automated and controlled in order to satisfy various control objectives. The models developed by the International Water Association (IWA) have been extensively used worldwide in order to design and assess the performance of various control strategies. In this work, we propose to review most recent WWTP automation initiatives around the world and identify most currently used control parameters and control architectures. We then suggest a framework to select WWTP model, control parameters and control scheme in order to develop and benchmark control strategies for WWTP automation.

• The Korean Journal of Ceramics
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• v.6 no.2
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• pp.138-142
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• 2000

Thin film $LiNbO_3$MFS (metal-ferroelectric-semiconductor) capacitor showed improved characteristics such as low interface trap density, low interaction with Si substrate, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$thin films grown directly on p-type Si (100) substrates by 13.56 MHz RF magnetron sputtering system for FRAM (ferroelectric random access memory) applications. RTA (rapid thermal anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60sec. We learned from X-ray diffraction that the RTA treated films were changed from amorphous to poly-crystalline $LiNbO_3$which exhibited (012), (015), (022), and (023) plane. Low temperature film growth and post RTA treatments improved the leakage current of $LiNbO_3$films while keeping other properties almost as same as high substrate temperature grown samples. The leakage current density of $LiNbO_3$films decreased from $10^{-5}$ to $10^{-7}$A/$\textrm{cm}^2$ after RTA treatment. Breakdown electric field of the films exhibited higher than 500 kV/cm. C-V curves showed the clockwise hysteresis which represents ferroelectric switching characteristics. Calculated dielectric constant of thin film $LiNbO_3$illustrated as high as 27.9. From ferroelectric measurement, the remanent polarization and coercive field were achieved as 1.37 $\muC/\textrm{cm}^2$ and 170 kV/cm, respectively.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.106-112
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• 2017

BACKGROUND: Kale (Brassica oleracea) biosynthesizes various phytochemicals including glucosinolates, flavonoids, and carotenoids. Phytochemicals of plants are influenced by light, temperature, carbon dioxide, and growing conditions. Specifically, carotenoids are affected by temperature, light, and oxygen. The aim of this study was to investigate the effect of cold stress (day/night: $25^{\circ}C/20^{\circ}C$, $20^{\circ}C/15^{\circ}C$, $15^{\circ}C/10^{\circ}C$) on carotenoids in kale leaves. METHODS AND RESULTS: Kale was grown in pots for up to 50 days after sowing (DAS) in a greenhouse. For cold acclimation experiments, kale grown in growth chambers for 3 days and was subjected to low temperature for 4 days. The conditions maintained in the growth chambers were as follows: photoperiod, 12/12 h (day/night); light, fluorescent; and relative humidity, 60%. Carotenoid (lutein, ${\alpha}-carotene$, zeaxanthin, ${\beta}-carotene$) contents were analyzed by high-performance liquid chromatography (HPLC). The total carotenoid content gradually increased during cold acclimation for 3 days. When kale was subjected to cold stress, the total carotenoid content was high at $25^{\circ}C/20^{\circ}C$ treatment, but low at $15^{\circ}C/10^{\circ}C$ treatment. The total carotenoid content of kale leaves continuously grown in greenhouse decreased from 50 to 57 DAS (1,418 and 1,160 mgkg-1 dry wt., respectively). The lutein, ${\alpha}-carotene$, and ${\beta}-carotene$ contents were very low and the zeaxanthin contents were very high at $15^{\circ}C/10^{\circ}C$ treatment. When kale was subjected to cold stress, the ratio of individual to the total carotenoid contents of kale leaves was 4553% for -carotene and 210% for zeaxanthin. CONCLUSION: The ${\beta}-carotene$ and zeaxanthin contents in kale leaves indicate their sensitiveness toward cold stress.

• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.793-801
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• 2018

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha ($HIF-1{\alpha}$), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.317-324
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• 2019

The purpose of this study was to investigate the effects of sports massage in the recovery period after maximal exercise on heart rate(HR), oxygen uptake(OU), and blood lactate(BL) of ssireum players. The participants of this study were consisted of 24 ssireum players in university team(UT) and business team(BT). The first experiment had a rest recovery period for 20 minutes after the maximal exercise, and the second experiment gave a sports massage was performed the order of abdominal, waist and lower legs in a prone position for 20 minutes. The interaction effects of massage treatment and recovery period in HR showed a higher recovery ability in both the UT and BT when the massage treatment was given 10 minutes after recovery than when it was not given. The main effects of recovery period showed in all variables of HR, OU, and BL. The main effects of BL on massage treatment was significant low in both the UT and BT when the massage was given. And, the main effects of OU was significantly lower only in the BT. In conclusion, compared sports massage treatment on ssireum players after maximal exercise positively affected the recovery mechanism of HR, OU, and BL than the rest recovery method.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4441-4448
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• 2022

The electrochemical oxidation process has been widely studied in the field of wastewater treatment for the decomposition of organic materials through oxidation using ·OH generated on the anode. Pt anode electrodes with high durability and long-term operability have a low oxygen evolution potential, making them unsuitable for electrochemical oxidation processes. Therefore, to apply Pt electrodes that are suitable for long-term operation and large-scale processes, it is necessary to develop a new method for improving the decomposition rate of organic materials. This study introduces a method to improve the decomposition rate of organic materials when using a Pt anode electrode in the electrochemical oxidation process for the treatment of organic decontamination liquid waste. Electrochemical decomposition tests were performed using sodium dodecylbenzenesulfonate (SDBS) as a representative organic material and a Pt mesh as the anode electrode. Y₂O₃ particles were introduced into the electrolytic cell to improve the decomposition rate. The decomposition rate significantly improved from 21% to 99%, and the current efficiency also improved. These results can be applied to the electrochemical oxidation process without additional system modification to enhance the decomposition rate and current efficiency.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.287-294
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• 1995

Studies were carried out to elucidate the efficacy of exogeneous 20-hydroxyecdysone treatment on terminating pupal diapause in the fall webworm. Hyphantria cunea Drury. And the difference was also investigated between normal adult development and post-diapause development after 20-hydroxyecdysone treatment. In the diapause termination rate of pupae treated with 20-hydroxyecdysone after storage for various periods at 16L:8D and $25\pm$$1^{\circ}C$, at the highest rate was observed from the group stored for the longest period and the lowest rate from those stored for 1.5 months. The time needed for adult emergence was inversely proportional to the chilling (at $0\pm$$1^{\circ}C$) period, and the longer its exposure period at low temperature, the higher its sensitivity to 20-hydroxyecdysone treatment. Pupal diapause duration was almost the same, regardless of storage period in the total darkness or at the photoperiod of 16L:8D, and also they successfully emerged to adult even without any experience at low temperature. The oxygen consumption rate in normally developing pupae showed nearly a typical U-form. But, that of diapausing pupae treated with 20-hydroxyecdysone slowly increased and jumped 14 days after the treatment. Pupal diapause began before formation of adult tissues, an a timing of adult tissue formation coincided with ascending timing of the metabolic rate in both normally developing pupae and diapausing pupae treated with 20-hydroxyecdysone. The diapausing pupae treated with 20-hydroxyecdysone was similar to normally developing pupae in band patterns of proteins from haemolymph or fat body.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.138-146
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• 2018

Photodynamic therapy (PDT) is a great potential approach for the localized tumor removal with fewer metastatic potentials and side effects in treating the disease. In the treatment process, a photosensitizer (PS) that absorbs a light energy to generate reactive oxygen is essential. In general, a visible light is used as a light source of PDT, so that side effects from the light source are inevitable. For this reason, upconversion nanoparticles (UCNPs) using near-infrared (NIR) as an excitation source are attracting attention in the field of disease diagnosis and treatment. UCNPs have the low cytotoxicity and phototoxicity, and also advantages such as deep tissue penetration and low background autofluorescence. For PDT, UCNPs should be combined with a PS which absorbs the light energy from UCNPs and transfers it to the surrounding oxygen to produce reactive oxygen. In addition, the therapeutic efficacy can be improved by modifying nanoparticle surfaces, adding anti-cancer drugs, or combining with photothermal therapy (PTT). In this review, we summarize the recent research to improve the efficiency of PDT using UCNPs.

• Journal of Technologic Dentistry
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• v.23 no.1
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• pp.31-43
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• 2001

This study was performed to observe the micro-structure change of surface, behavior of oxide change of element, the component transformation of the alloy and the bonding strength between the porcelain interface in order to investigate effects of indium, tin on interfacial properties of porcelain fused to low gold alloy. Hardness of castings was measured with a micro-Vicker's hardness tester. The compositional change of the surface of heat-treated specimen was analyzed with an EDS and an EPMA. The interfacial shear bonding strength between alloy specimen and fused porcelain was measured with a mechanical testing system(MTS 858.20). The results were as follows: 1) The hardness value of alloy increased as increasing amount of indium addition. 2) The formation of oxidation increased as increasing indium and tin contents after heat treatment. 3) Diffusion of indium and tin elements increased as increasing indium and tin contents in metal-porcelain surface after porcelain fused to metal firing. 4) The most interfacial shear bonding strength was increased as increasing a composition of adding elements, and a heat-treatment time, and an oxygen partial pressure. From the results of this study it was found that the addition of alloying elements such as indium and tin increase hardness of as-cast alloy, produce surface oxide layer of adding elements by heat-treatment which may improve interfacial bonding strength between alloy and porcelain.