• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.30-36
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• 2021

Residual life assessment of reformer tubes of mod HP steel used in the refinery and petrochemical industry were investigated by quantitative metallographic evaluation method. Area fractions of precipitated carbides were measured by using surface replication and its relationship with the remaining life of the tube was investigated. The microstructures of the virgin and other tubes were examined using optical microscopy (OM) for service periods of 1.8, 6.0, 7.2, 8.5, 9.7, and 16.2 years at 950 ℃ and the area fractions of the precipitates were measured by image analysis using ImageJ software. As the area fraction of the precipitates increased, the residual life was decreased accordingly. The results showed that the LMP was the highest in the virgin and the LMP decreased as the service time increased and the residual life decreased. A regressional equation showing the relation between the area fraction of carbides and LMP was experimentally derived. The obtained relationship can be used with the surface replication method for on-site residual life assessment.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1327-1337
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• 2018

Aviation fuel oil is more strictly controlled than other transport fuels because it can lead to major accidents in the event of a problem. The quality standards of the aircraft are specified by the domestic Korean Standard, the American Society for Testing and Materials and the International Air Transport Association, respectively. From 2016 to 2017, the quality analysis of 6 items such as aromatic content, sulfur content and distillation characteristics was carried out on the jet fuel produced at five domestic refineries. Domestic production of jet fuel has been shown to be in conformity with the quality standards and has been maintained at a constant level throughout the year. Compared with the specification of ASTM and IATA the aromatic content of domestic KS specification is set to be strictly 1.5 wt% higher than the ASTM and IATA setting specification, but it satisfies this specification sufficiently. In addition, other items such as sulfur content, distillation property and flash point satisfied both domestic and international specification.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.428-435
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• 2018

In this study, we isolated and identified bacteria from freshwater and soil collected from Osang reservoir, to screen antimicrobial bacteria against various pathogenic bacteria. 38 strains were isolated and assigned to the class Proteobacteria (22 strains), Actinobacteria (7 strains), Bacteroidets (6 strains), and Firmicutes (3 strains) based on 16S rRNA gene sequence analysis. Among them, strain OS17 showed a good growth inhibition against 5 methicillin-resistant Staphylococcus aureus subsp. aureus strains and Bacillus cereus, Bacillus subtilis, Filobasidium neoformans. As a result of the 16S rRNA gene sequence analysis, strain OS17 show the high similarity with Burkholderia ambifaria $AMMD^T$, B. diffusa $AM747629^T$, B. tettitorii $LK023503^T$ 99.8%, 99.7%, 99.6%, respectively. We investigated cell growth and antimicrobial activity according to commercial culture medium, temperature, pH for culture optimization of strain OS17. Optimal conditions for growth and antimicrobial activity in strain OS17 were found to be: YPD medium, $35^{\circ}C$ and pH 6.5. When the strain was cultured in LB, NB, TSB, R2A media at $20^{\circ}C$ and $25^{\circ}C$, the antimicrobial activity did not show. Culture filtrate of strain OS17 showed antimicrobial activity against 5 MRSA strains, Bacillus cereus, Bacillus subtilis, and Filobasidium neoformans with inhibition zones from 2 to 8 mm. Optimal reaction time was 48 h in YPD medium, 100 rpm and 0.3 vvm in 2 L-scale fed-batch fermentation process for antimicrobial activity. Culture optimization of strain OS17 can be improved on antimicrobial activity. Therefore, the antimicrobial activity of Burkholderia sp. OS17 had potential as antibiotics for pathogens including MRSA.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.96-106
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• 2020

To solve the limitation of traffic monitoring that occur from embedded sensor such as loop and piezo sensors, the thermal imaging camera was installed on the roadside. As the length of Class 1(passenger car) is getting longer, it is becoming difficult to classify from Class 3(2-axle truck) by using an embedded sensor. The collected images were labeled to generate training data. A total of 17,536 vehicle images (640x480 pixels) training data were produced. CNN (Convolutional Neural Network) was used to achieve vehicle classification based on thermal image. Based on the limited data volume and quality, a classification accuracy of 97.7% was achieved. It shows the possibility of traffic monitoring system based on AI. If more learning data is collected in the future, 12-class classification will be possible. Also, AI-based traffic monitoring will be able to classify not only 12-class, but also new various class such as eco-friendly vehicles, vehicle in violation, motorcycles, etc. Which can be used as statistical data for national policy, research, and industry.

• Korean Journal of Construction Engineering and Management
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• v.24 no.6
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• pp.63-65
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• 2023

BIM and AR technologies have been assessed as a means of enhancing productivity within the construction industry, through the provision of effortless access to critical data on site, achieved via the projection of 3D models and associated information onto actual structures. However, most of the previous researches for applying AR technology in construction quality management has been performed for construction projects in general, resulting in only overall on-site management solutions. Also, a few previous researches for the application of AR in the quality management of specific elements like reinforcements focused only on simple projection, so conducting specific quality inspection was impossible. Hence, this study aimed to develop a practically applicable BIM-based AR quality management system targeted for reinforcements. For the development of this system, the reinforcement inspection items on the quality checklist used at railway construction sites were analyzed, and four types of AR functions that can effectively address these items were developed and installed. The validation result of the system for the actual railway bridge showed a degradation of projection stability. This problem was solved through model simplification and enhancement of the AR device's hardware performance, and then the normal operation of the system was validated. Subsequently, the final developed reinforcement quality inspection system was evaluated for practical applicability by on-site quality experts, and the efficiency of inspection would significantly increase when using the AR system compared to the current inspection method for reinforcements.

• Journal of Life Science
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• v.32 no.12
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• pp.919-928
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• 2022

As seen in the COVID-19 pandemic, unexpected emergence of new viruses presents serious concern on public health. Especially, the absence of effective vaccines or antiviral drugs against emerging viruses significantly increases the severity of disease and duration of viral circulation among population. Natural products have served as a major source for safe and effective antiviral drugs. In this study, we examined the virucidal activity of medical herb extracts with a view to discover novel antiviral agents with desired levels of safety and antiviral efficacy. Ethanol extracts of ten selected medical herbs were tested for antioxidant activity and in-vitro cytotoxicity in various animal cell lines. Of note, the herbal extracts showed broad and potent virucidal activities against rotavirus, hepatitis A virus, and influenza A virus. The extracts of Sorbus commixta and Glycyrrhiza uralensis showed strong virucidal activities against influenza A virus. We also examined whether the extracts of Sorbus commixta and Glycyrrhiza uralensis can be used as inactivating agents to prepare an inactivated viral vaccine. In a mouse model, influenza A virus inactivated by the extracts elicited high levels of neutralizing antibodies, and the vaccination provided complete protection against lethal challenge. These results suggest that herb-derived natural products can be developed to antiviral drugs as well as inactivating agents for preparation of inactivated viral vaccines.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.61-71
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• 2009

Most deciduous trees in temperate zone are dormant during the winter to overcome cold and dry environment. Dormancy of deciduous fruit trees is usually separated into a period of rest by physiological conditions and a period of quiescence by unfavorable environmental conditions. Inconsistent and fewer budburst in pear orchards has been reported recently in South Korea and Japan and the insufficient chilling due to warmer winters is suspected to play a role. An accurate prediction of the flowering time under the climate change scenarios may be critical to the planning of adaptation strategy for the pear industry in the future. However, existing methods for the prediction of budburst depend on the spring temperature, neglecting potential effects of warmer winters on the rest release and subsequent budburst. We adapted a dormancy clock model which uses daily temperature data to calculate the thermal time for simulating winter phenology of deciduous trees and tested the feasibility of this model in predicting budburst and flowering of Niitaka pear, one of the favorite cultivars in Korea. In order to derive the model parameter values suitable for Niitaka, the mean time for the rest release was estimated by observing budburst of field collected twigs in a controlled environment. The thermal time (in chill-days) was calculated and accumulated by a predefined temperature range from fall harvest until the chilling requirement (maximum accumulated chill-days in a negative number) is met. The chilling requirement is then offset by anti-chill days (in positive numbers) until the accumulated chill-days become null, which is assumed to be the budburst date. Calculations were repeated with arbitrary threshold temperatures from $4^{\circ}C$ to $10^{\circ}C$ (at an interval of 0.1), and a set of threshold temperature and chilling requirement was selected when the estimated budburst date coincides with the field observation. A heating requirement (in accumulation of anti-chill days since budburst) for flowering was also determined from an experiment based on historical observations. The dormancy clock model optimized with the selected parameter values was used to predict flowering of Niitaka pear grown in Suwon for the recent 9 years. The predicted dates for full bloom were within the range of the observed dates with 1.9 days of root mean square error.

• Food Science and Preservation
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• v.22 no.3
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• pp.392-398
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• 2015

The physicochemical properties of spray-dried rice flour with Lactobacillus plantarum CGKW3 were investigated. Amylose and damaged starch contents of spray-dried rice flour (S10, S20, S30, and S50) with L. plantarum CGKW3 were 14.18~17.75% and 24.65~34.08%, respectively. The particle size of spray-dried rice flour was $82.28{\sim}131.17{\mu}m$. The rice flour with L. plantarum CGKW3 showed a good powder flowability. The water absorption and water solubility of spray-dried rice flour were 1.96~2.13 and 9.91~21.95%, respectively. Thermal properties measured by differential scanning calorimeter revealed that the enthalpy (${\Delta}H$) for starch gelatinization were highest in the rice flour (S50) with L. plantarum CGKW3. When compared, the viable cell number of spray-dried rice flour were found to be in the following order: S10 (5.78 log CFU/g) < S20 (6.38 log CFU/g) < S30 (6.69 log CFU/g) < S50 (7.11 log CFU/g). The survaival rate of L. plantarum CGKW3 was 60.02-73.85%, which reflected the improvement in the quality of rice flour with an increase in treatment concentration. Based on our results, spray-dried rice flour with L. plantarum CGKW3 could be used in various types of rice foods.

• Food Science and Preservation
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• v.22 no.1
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• pp.134-144
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• 2015

The anti-diabetic effects of Allium tuberosum Rottler extracts (ATE) and ATE fermented with lactic acid bacteria in db/db mice were evaluated. The electron donating activity of ATE fermented with Lactobacillus plantarum, and Lactobacillus casei, respectively, increased compared to that of ATE, but the superoxide radical scavenging activity of the ATE incubated with L. plantarum decreased. The superoxide radical scavenging activity of the ATE fermented with both L. plantarum and L. casei was similar to that of the ATE. Therefore, fermented ATE (FATE) was prepared for in vivo testing by incubating it with both L. plantarum and L. casei. The db/db mice were divided into six groups: normal (non-diabetic mice), diabetic control (DM), and four experimental groups administered 200 or 400 mg/kg/day ATE (ATE200 and ATE400) and 200 or 400 mg/kg/day FATE (FATE200 and FATE400). Weight gain was significantly inhibited in the FATE200 group compared with that in the other db/db mice groups (p<0.05). The areas under the curve of the ATE400 and FATE400 groups were significantly smaller than that of the DM group in the glucose tolerance evaluation. The serum glucagon-like peptide-1 levels in the ATE400 and FATE400 groups increased. These results indicate that administering ATE and FATE may be effective against anti-hyperglycemia by regulating insulin resistance. In particular, FATE may be beneficial for controlling obesity in type 2 diabetes.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.327-333
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• 2014

A method for analysis of five artificial sweetners (sodium saccharin, aspartame, acesulfame-K, sucralose, cyclamate) in beverage samples was developed using high-performance liquid chromatography/triple quadrupole mass spectrometry (HPLC/MS/MS). The method uses a single-step dilution for sample preperation. Seperation was achieved on a $C_{18}$ column ($2.1{\times}150mm$, $3.5{\mu}m$) with A- 2% methanol (1 mM ammonium acetate), B-95% methanol (1 mM ammonium acetate) as mobile phase with gradient mode. The quantitation of target compounds was performed by external calibration in selected reaction monitorning (SRM) mode. The coefficient of determination of calibration curve for sodium saccharin, aspartame, acesulfame-K, sucralose and cyclamate were 0.9957, 0.9991, 0.9943, 0.9982 and 0.9948, respectively. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 0.001~0.022 mg/L and 0.004~0.073 mg/L, repectively. Recoveries for beverage samples were in the range of 92.76~113.50% with RSD < 10.91%. The method has applied to the determination of the five sweetners in 102 beverage samples. Three artificial sweetners-aspartame, acesulfame-K, sucralose were detected from 42 samples. Sodium saccharin and cyclamate were not detected in all samples.