• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.3
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• pp.465-475
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• 2022

Due to the impact of COVID-19, people are paying attention to convenience and health, and the use of IoT devices to help them is increasing. In order to embed a lightweight security element in IoT devices that need to handle sensitive information even with limited resources, the development of a lightweight S-box is essential. Until 2021, it was common to develop a lightweight 4-bit S-box by a heuristic method, and to develop an extended structure or repeat the same operation for a larger size lightweight S-box. However, in January 2022, a paper that proposed a heuristic algorithm to find an 8-bit S-box with better differential uniformity and linearity than the S-box generated with an MISTY extended structure, although non-bijective, was published [1]. The heuristic algorithm proposed in this paper generates an S-box by adding AND operations one by one. Whenever an AND operation is added, they use a method that pre-removes the S-box for which the calculated differential uniformity does not reach the desired criterion. In this paper, we improve the performance of this heuristic algorithm. By increasing the amount of pre-removal using not only differential uniformity but also other differential property, and adding a process of calculating linearity for pre-removing, it is possible to satisfy not only differential security but also linear security.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.386-391
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• 2022

This study is about a technique for obtaining collagen by extracting fat by treating collagen-containing liposuction effluent in the presence of supercritical fluid. Using a supercritical solvent, a collagen extract could be obtained from animal-derived fat in a short time (about 6 hours), and about 2-3% of collagen by mass compared to the raw material could be obtained. The presence of collagen in the extract obtained by supercritical extraction was confirmed by SDS-PAGE, and it was confirmed that it was type 1 collagen having a relatively large molecular weight. In addition, the growth factors of IGF-1, bFGF, VEGF and NGF were analyzed to find out which growth factors were present in the collagen obtained by supercritical extraction, and it was found that these growth factors were contained in the extract. There was no significant difference in DNA content per mg of sample before and after supercritical treatment. Further in-depth studies are likely to be needed on decellularization technology using the supercritical process. In conclusion, the extracellular matrix obtained through the solvent extraction process using a supercritical fluid contains growth factors above a certain amount even after decellularization and removal of fat, so that it was found that not only biocompatibility is greatly increased, but also tissue regeneration can be rapidly induced.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.4
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• pp.70-77
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• 2023

Fine dust is a cause of serious ecological problems, and fugitive dust generated from construction sites is a major source of fine dust in Korea. However, at construction sites, including concrete manufacturing industry sites, measurements are rarely made at the fugitive dust generation stage, and passive removal methods are the majority. Therefore, in this study, a fugitive dust measurement method suitable for managing fugitive dust generated during aggregate unloading in the concrete manufacturing industry sites was selected. In addition, the purpose was to analyze the amount of fugitive dust reduction according to the operation of the reduction system by applying the automatic fugitive dust reduction system to the aggregate unloading site. As a result, the reliability of the light scattering method was secured through the comparative measurement of the beta-ray absorption method and the light scattering method, and the light scattering method correction coefficient was calculated and applied to the measured value of the fugitive dust particle mass concentration at the concrete manufacturing industry sites. In addition, the fugitive dust reduction rate according to the operation of the automatic fugitive dust reduction system was derived.

• Clean Technology
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• v.16 no.4
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• pp.277-283
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• 2010

Eosin Y is used a colorant and dye but eosin Y is harmful toxic substance. In this study, the adsorption characteristics of granular activated carbon have been investigated for the adsorption of eosin dye dissolved in water. The effects of initial dye concentration, contact time, pH and temperature on adsorption of eosin by a fixed amount of activated carbon have been studied in batch adsorber and fixed bed. The adsorptivity of activated carbon for eosin Y were largely improved by pH control. When the pH was 3 in the sample, the eosin Y could be removed 99% of initial concentration (10 mg/L). The adsorption equilibrium data are successfully fitted to the Freundlich isotherm equation in the temperature range from 293 to 333 K. The estimated values of k and ${\beta}$ are 19.56-134.62, 0.442-0.678, respectively. The effects of the operation conditions of the fixed bed on the breakthrough curve were investigated. When the inlet eosin Y concentration is increased from 10 to 30 mg/L, the corresponding adsorption breaktime appears to decrease from 470 to 268 min at bed height of 3 cm and a constant flow rate of 2 g/min. When the initial eosin Y flow rate is increased from 1 to 3 g/min, the corresponding adsorption breaktime appears to decrease from 272 to 140 min at bed height of 3 cm and inlet concentration of 10 mg/L. Also, breaktime increased with increasing bed height at flow rate of 2 g/min and inlet concentration of 10 mg/L. And length of adsorption zone showed similar patterns.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.63-70
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• 2023

Golden apple snails (Pomacea canaliculat) (GAS) are widely used for weed control in rice cultivation. However, concerns on the ecological risk of invasive GAS species are increasing. This study aimed to evaluate the overall impacts of GAS on weed control, abundance of aquatic animals and insects, and rice yield, in comparison with that from other biocontrol agents such as loach (Misgurnus mizolepis) and catfish (Silurus asotus), which are alternatives for biological weed control in rice paddy cultivation. Field experiments included five treatments; control, herbicide, GAS, loach, and catfish. During the rice growth, weed appearance and biological abundance were monitored, and at harvest, the rice yield was determined. Weed control efficiency was the highest for GAS treatment (100%), followed by that for herbicide (95.8%), loach (57.5%), and catfish treatments (31.7%). Insect abundance was considerably decreased in GAS treatment due to heavy weed removal, which affects the habitat of aquatic animals and insects. The amount of rice yield (unit: kg 10 a^-1) was in the order of GAS (798.9) > loach (708.1) = herbicide (700.7) > catfish (629.4) > control (496.0). Therefore, considering the weed control efficiency, biological abudance, and rice yield, loach could be a potential alternative for biological weed control in organic rice farming. However, the activity of the biocontrol agents are susceptible to environmental conditions; therefore, further studies under different conditions are essential to confirm these findings.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.472-478
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• 2023

In this study, the acetaldehyde removal characteristics of activated carbon (AC) for air purifier filters were investigated using metal catalysts-impregnation and functional group-modification method. The AC with a high specific surface area(1700 m²/g) and micropores was prepared by KOH activation of coconut charcoal and the efficiency of catalyst and functional group immobilization was examined by varying the drying conditions within the pores after immersion. The physical properties of the prepared activated carbon were analyzed by BET, ICP, EA, and FT-IR, and the acetaldehyde adsorption performances were investigated using gas chromatography (GC) at various impregnation and modified conditions. As the concentration of impregnation solution increased, the amount of impregnated metal catalysts increased, while the specific surface area showed a decreasing trend. The adsorption tests of the metal catalyst-impregnated and functional group-modified activated carbons revealed that excellent adsorption performance in compositions MgO10@AC, CaO10@AC, EU10@AC, and H-U3N1@AC, respectively. The MgO10@AC, which showed the highest adsorption performance, had a breakthrough time of 533.8 minutes and adsorption capacity of 57.4 mg/g for acetaldehyde adsorption. It was found that the nano-sized MgO catalyst on the activated carbon improved the adsorption performance by interacting with carbonyl groups of acetaldehyde.

• Korean Chemical Engineering Research
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• v.61 no.3
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• pp.407-411
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• 2023

The urease is covalently immobilized on the surface of the magnetic particles to catalyze the conversion of urea to bicarbonate anion. The conversion was confirmed qualitatively using high-pressure liquid chromatography and UV/Vis spectrometry, and analyzed quantitatively with cyclic voltammetry. The amount of conversion with respect to time was measured and analyzed by the reaction rate equation to calculate a reaction rate constant of 0.0474 min-1. In the 1 to 3 cycles, a conversion percentage of over 90% was found, and it was possible to reuse the urease 8 times up to the percentage of 50%. It was also observed that the stability evaluated for storage for 30 days was maintained. As a result of this study, it can be seen that the urease covalently immobilized on the scaffold can be used for urea removal for the purpose of producing ultrapure water.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.4
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• pp.165-171
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• 2006

This is the research to prepare a purification program for relatively less polluted stream by using phytoremediation. We calculated a treatment amount of nutrients followed by growth of Helianthus annuus (a kind of sunflower), setting up the plant reactor in the hothouse. Moreover, to investigate a field applicability, we could find increased contents of nitrogen, carbon and hydrogen in plants by setting up a H. annuus planted artificial floating island in an irrigation canal. When we changed the dissolved inorganic nitrogen(DIN) concentration of the influent from 28.5 to 199.2 mg/l and the dissolved inorganic phosphorus(DIP) concentration of the influent from 13.3 to 25.4 mg/l, growth disorder has not appeared though it is much higher than the criterion of water for irrigation. In this case, the removal rate of DIN was $81.7\sim98.6%$, and that of DIP was $81.9\sim98.4%$ in 3 days stay on average. It has appeared that the efficient hydraulic retention time(HRT) was 48 hours. The following contents of nitrogen, carbon and hydrogen of H. annuus appeared in the artificial floating island: nitrogen was $3.2\sim7.8%$ in the trunk and $3.0\sim6.3%$ in the root. Carbon was $40.1\sim57.7%$ in the trunk and $43.4\sim53.8%$ in the root.

• Journal of the Korea Institute of Construction Safety
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• v.6 no.1
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• pp.12-18
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• 2024

High-rise, large-scale, and diversification of buildings are possible, and the reduction of concrete cross-sections reduces the weight of the structure, thereby increasing or decreasing the height of the floor, securing a large number of floors at the same height, securing a large effective space, and reducing the amount of materials, rebar, and concrete used for designating the foundation floor. In terms of site construction and quality, a low water binder ratio can reduce the occurrence of dry shrinkage and minimize bleeding on the concrete surface. It has the advantage of securing self-fulfilling properties by improving fluidity by using high-performance sensitizers, making it easier to construct the site, and shortening the mold removal period by expressing early strength of concrete. In particular, with the rapid development of concrete-related construction technology in recent years, the application of ultra-high-strength concrete with a design standard strength of 100 MPa or higher is expanding in high-rise buildings. However, although high-rise buildings with more than 120 stories have recently been ordered or scheduled in Korea, the research results of developing ultra-high-strength concrete with more than 130 MPa class considering field applicability and testing and evaluating the actual applicability in the field are insufficient. In this study, in order to confirm the applicability of ultra-high-strength concrete in the field, a preliminary experiment for the member of a reduced simulation was conducted to find the optimal mixing ratio studied through various indoor basic experiments. After that, 130 MPa-class ultra-high-strength concrete was produced in a ready-mixed concrete factory in a mock member similar to the life size, and the flow characteristics, strength characteristics, and hydration heat of concrete were experimentally studied through on-site pump pressing.

• Journal of Chest Surgery
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• v.32 no.2
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• pp.130-137
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• 1999

Background: In cardiac surgery, hypothermia is associated with a number of major disadvantage, including its detrimental effects on enzymatic function, energy generation and cellular integrity. Warm cardioplegia with normothermic cardiopulmonary bypass cause three times more incidence of permanent neurologic deficits than the cold crystalloid cardioplegia with hypothermic cardiopulmonary bypass. Interruptions or inadequate distribution of warm cardioplegia may induce anaerobic metabolism and warm ischemic injury. To avoid these problems, tepid blood cardioplegia was recently introduced. Material and Method: To evaluate whether continuous tepid blood cardioplegia is beneficial in clinical practice during valvular surgery, we studied two groups of patients matched by numbers and clinical characteristics. Warm group(37$^{\circ}C$) consisted of 18 patients who underwent valvular surgery with continuous warm blood cardioplegia. Tepid group(32$^{\circ}C$) consisted of 17 patients who underwent valvular surgery with continuous tepid blood cardioplegia. Result: Heartbeat in 100% of the patients receiving continuous warm blood cardioplegia and 88.2% of the patients receiving continuous tepid blood cardioplegia converted to normal sinus rhythm spontaneously after removal of the aortic cross clamp. There were no differences between these two groups in CPB time, ACC time, the amount of crystalloid cardioplegia used and peak level of potassium. During the operation, the total amount of urine output was more in the warm group than the tepid group(2372${\pm}$243 ml versus 1535${\pm}$130 ml, p<0.01). There were no differences between the two groups in troponin T level measured 1hr and 12hrs after the operation. Conclusion: Continuous tepid blood cardioplegia is as safe and effective as continuous warm blood cardioplegia undergoing cardiac valve surgery in myocardial protection.