• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.22-28
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• 2021

Combustion characteristics were examined experimentally for a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. An original model and a variant with a different fuel injection pattern are tested to compare their combustion characteristics such as NOx, CO and stability in pressurized conditions with single burner-flame and in an ambient multi-flame conditions with multi-burners. Test results show that NOx emissions are smaller for the variant, whose number of fuel holes is reduced with the same total area of fuel holes, in ambient and pressurized single-flame conditions with single burner, which results from enhanced fuel/air mixing due to a higher penetration of fuel into the air stream. The multi-burnerflame test results show that NOx emissions are smaller for the variant due to reduced flame interactions, which, on the contrary, slightly reduces the stability margin. On-site test results fromin an actual power plants also show that NOx emissions are reduced for the variant, compared with the original one, which is in agreement with the lab test results stated above.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.96-107
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• 2022

The purpose of this study was to demonstrate the effects of 8weeks Kettlebell training on the FMS and Balance in Middle school baseball player. Fourteen middle school baseball players were randomly assigned to a kettlebell group (n=8) and a control group (n=6), and kettlebell training was applied twice a week for 60 minutes. And the FMS, Y-balance test and static and dynamic balance test using smart shoes were tested before and after kettlebell training. Repeated two-way ANOVA measures was performed both before and after the exercise to verify the effect of kettlebell training. Also, if there was an interaction between time and group, a paired sample t-test was performed for each group. As a results of the study, FMS score showed a significant difference in IL (Inline Lunge) and TS(Total Score), and there was no significant difference in other variables of FMS. The YBT score showed a significant difference in all YBT variables except for the left AT. And the balance test using smart shoes, there was no significant interaction effect between group and period in all variables. In conclusion, it was found that the application of kettlebell training in middle school baseball players had an effects on the FMS and YBT scores related to functional movement and functional balance, but it did not affect the static/dynamic balance test using smart shoes evaluated by the foot pressure method. It seems that the results of this study can be provided as basic data necessary for planning a training program for middle school baseball players.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.23-29
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• 2022

Although tropical cyclones with wind speeds weaker than 17 ms^-1 (weak tropical cyclones: WTCs) can cause significant damage, particularly over the Seoul metropolitan area, only a few studies have focused on WTC activity over South Korea. In this study, we found that WTC activity is likely associated with the Pacific Decadal Oscillation (PDO). During the negative phases of the PDO, landfall frequency of WTCs increased significantly compared to the positive phases at 95% confidence level. When related to the negative phases of the PDO, a positive relative vorticity anomaly is found in the northern sector of the western North Pacific while a negative relative vorticity anomaly and enhanced vertical wind shear prevail in the southern sector of the WNP. These factors are favorable for the northward shift of the genesis location of tropical cyclones on average, thereby reducing the total lifetime of WTCs. Moreover, a high-pressure anomaly over the Japanese islands would shift a tropical cyclone track westward in addition to the landfall location. Consequently, the effects of the topographical friction and the Yellow Sea Bottom Cold Water on a tropical cyclone may increase. These conditions could result in a weaker lifetime maximum intensity and landfall intensity, ultimately resulting in WTCs becoming more frequent over South Korea during the negative phases of the PDO.

• Journal of the Korean Geotechnical Society
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• v.37 no.11
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• pp.71-81
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• 2021

The purpose of this study is liquefaction phenomenon was simulated using the 1g shaking table test. Analysis of liquefaction and Re-liquefaction behavior according to the ground conditions was analyzed when an embankment exists above the ground. The soil used in the experiment was silica sand and the ground composition was a liquefied layer of 50cm (Case 1), a non-liquefied layer of 17.5cm and a liquefied layer of 32.5cm (Case 2). The embankment was formed by fixing the height of 10cm and the slope of the slope at a ratio of 1:1.8. For seismic waves, excitation of a 5Hz sine wave was performed for 8 seconds, and a total of 5 case excitations were performed. In Case 1, it was confirmed that liquefaction occurred at all depths during the first vibration excitation at the free-field and that liquefaction did not occur at all depths except 5cm at the third vibration excitation. At the center of the embankment, liquefaction occurred up to a depth of 20cm during the first vibration excitation, and it was confirmed that liquefaction did not occur at all depths except for a depth of 5cm during the second vibration excitation.

• Journal of Biomedical Engineering Research
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• v.43 no.3
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• pp.136-146
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• 2022

In this study, it is intended to provide basic data that can help develop a cardiovascular simulator for performance evaluation of pulse wave detectors by identifying the development status of domestic and overseas cardiovascular simulators. A total of 119 papers were selected by excluding duplicate literature, gray literature, and literature not related to a cardiovascular simulator. Based on the selected literature, the research trend of cardiovascular simulators was analyzed. As a result of analyzing the purpose of the study, most of the simulators were developed to evaluate the hemodynamic properties of artificial hearts and valves. In addition, it was used for simulation evaluation or hemodynamic studies such as pulse wave studies. As a result of analyzing configurations of the simulators, a heart most often consisted of only one left ventricle. For blood vessels, the Windkessel model was most often constructed using chambers and valves. In most studies, blood was reproduced by mixing glycerin and water to reproduce both density and viscosity. In addition, as a result of analysis from the perspective of medical device performance evaluation, simulators for evaluating artificial heart and artificial valves have been studied a lot, whereas simulators for blood pressure, pulse wave, and blood flow devices have been relatively insignificant. Based on the review results, we suggested considerations when developing a simulator for performance evaluations of a pulse wave detector.

• Nutrition Research and Practice
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• v.16 no.1
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• pp.60-73
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• 2022

BACKGROUND/OBJECTIVES: The extract from Dendropanax morbifera exhibited diverse therapeutic potentials. We aimed to evaluate the efficacy and safety of D. morbifera leaf extract for improving metabolic parameters in human. SUBJECTS/METHODS: A 12-week, double blind, placebo-controlled and randomized trial included a total of 74 adults, and they were assigned to the placebo group (n = 38) or 700 mg/day of D. morbifera group (n = 36). The efficacy endpoints were changes in glycemic, lipid, obesity, and blood pressure (BP) parameters, in addition to the prevalence of metabolic syndrome (MetS) and the numbers of MetS components. Safety was assessed by monitoring adverse events (AEs). RESULTS: After 12 weeks of treatment, the hemoglobin A1c (HbA1c) level significantly decreased in the D. morbifera group compared to that of the placebo group (difference: -0.13 ± 0.20% vs. 0.00 ± 0.28%, P = 0.031; % of change: -2.27 ± 3.63% vs. 0.10 ± 5.10%, P = 0.025). The homeostatic model assessment for insulin resistance level also decreased significantly from its baseline in the D. morbifera group. The systolic BP of D. morbifera group decreased significantly than that of placebo group (difference: -3.9 ± 9.8 mmHg vs. 3.3 ± 11.7 mmHg, P = 0.005; % of change: -2.8 ± 7.7% vs. 3.3 ± 10.2%, P = 0.005). However, the lipid parameters and body composition including body weight did not differ between the groups. The prevalence of MetS (36.8% vs. 13.9%, P = 0.022) and the incidence of MetS (10.5% vs. 13.9%, P = 0.027) at 12 weeks was significantly lower in the D. morbifera group than it was in the placebo group. No serious AEs occurred in either group. CONCLUSIONS: Supplementation with D. morbifera extracts over a 12-week period improved metabolic parameters such as HbA1c and BP and reduced the prevalence of MetS.

• Journal of The Korean Society of Clinical Toxicology
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• v.19 no.2
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• pp.83-92
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• 2021

Purpose: Glyphosate herbicide (GH) is a widely used herbicide and has been associated with significant mortality as poisoned cases increases. One of the reasons for high toxicity is thought to be toxic effect of its ingredient with glyphosate. This study was designed to determine differences in the clinical course with the salt-type contained in GH. Methods: This was a retrospective study conducted at a single hospital between January 2013 and December 2017. We enrolled GH-poisoned patients visited the emergency department. According to salt-type, patients were divided into 4 groups: isopropylamine (IPA), ammonium (Am), potassium (Po), and mixed salts (Mi) groups. The demographics, laboratory variables, complications, and their mortality were analyzed to determine clinical differences associated with each salt-type. Addtionally, we subdivided patients into survivor and non-survivor groups for investigating predictive factors for the mortality. Results: Total of 348 GH-poisoned patients were divided as follows: IPA 248, Am 41, Po 10, and Mi 49 patients. There was no difference in demographic or underlying disease history, but systolic blood pressure (SBP) was low in Po group. The ratio of intentional ingestion was higher in Po and Mi groups. Metabolic acidosis and relatively high lactate level were presented in Po group. As the primary outcome, the mortality rates were as follows: IPA, 26 (10.5%); Am, 2 (4.9%); Po, 1 (10%); and Mi, 1 (2%). There was no statistically significant difference in the mortality and the incidence of complications. Additionally, age, low SBP, low pH, corrected QT (QTc) prolongation, and respiratory failure requiring mechanical ventilation were analyzed as independent predictors for mortality in a regression analysis. Conclusion: There was no statistical difference in their complications and the mortality across the GH-salt groups in this study.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.363-377
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• 2021

The present study investigated the effects of dynamic tubing gait training(I and II) on the postural alignment, gait, and quality of life in chronic patients with Parkinson's disease. This study is based on the case study that recruited a total of 3 patients with chronic Parkinson's disease (Hoehn and Yahr Stage of 1 to 3 each one person). Dynamic tubing gait training (I and II) applied to chronic patients with Parkinson's disease for 25 sessions, 30 minutes a day, 5 days a week, over 5 weeks period. To investigate the effects of this study, evaluating using the postural alignment test, muscle activity tests, gait analysis, and quality of life scale for patient with Parkinson's disease. After the intervention of Dynamic tubing gait training (I and II), Trunk flexion was decreased. Also, during walking from initial contact (IC) to mid stance (Mst), muscle activity of Quadriceps, Hamstring, and Tibialis Anterior (TA) was increased and muscle activity of Gastrocnemius was decreased. The muscle activation of Erector Spinae (ES T12, L3) was increased in the H&Y I and III stages and decreased in the H&Y II stage. Length of gait line, single support line, ant/post position and lateral symmetry of center of pressure (COP) parameters improved. The spatio-temporal gait parameters including of step length, stride length, and velocity was increased, and cadence decreased. Further the quality of life of patients with Parkinson's disease was improved. Based on these findings, Dynamic tubing gait training (I and II) could be applied as a new approach to improve posture, gait, quality of life in chronic patients with Parkinson's disease for more than 5 years, whose drug resistance is halved.

• Journal of Dental Anesthesia and Pain Medicine
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• v.23 no.1
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• pp.19-28
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• 2023

Background: Fearful and anxious patients who find dental treatment intolerable without sedative and analgesic support may benefit from moderate sedation. Target controlled infusion (TCI) pumps are superior to bolus injection in maintaining low plasma and effect-site concentration variability, resulting in stable, steady-state drug concentrations. We evaluated the safety and efficacy of moderate sedation with remifentanil and propofol using TCI pumps in non-hospital dental settings. Methods: A prospective chart review was conducted on 101 patients sedated with propofol and remifentanil using TCI pumps. The charts were completed at two oral surgeons and one general dentist's office over 6 months. Hypoxia, hypotension, bradycardia, and over-sedation were considered adverse events and were collected using Tracking and Reporting Outcomes of Procedural Sedation (TROOPS). Furthermore, patient recovery time, sedation length, drug dose, and patient satisfaction questionnaires were used to measure sedation effectiveness. Results: Of the 101 reviewed sedation charts, 54 were of men, and 47 were of women. The mean age of the patients was 40.5 ±18.7 years, and their mean BMI was 25.6 ± 4.4. The patients did not experience hypoxia, bradycardia, and hypotension during the 4694 min of sedation. The average minimum Mean Arterial Pressure (MAP) and heartbeats were 75.1 mmHg and 60.4 bpm, respectively. 98% of patients agreed that the sedation technique met their needs in reducing their anxiety, and 99% agreed that they were satisfied with the sedation 24 hours later. The average sedation time was 46.9 ± 55.6 min, and the average recovery time was 12.4 ± 4.4 min. Remifentanil and propofol had mean initial effect-site concentration doses of 0.96 µ/.ml and 1.0 ng/ml respectively. The overall total amount of drug administered was significantly higher in longer sedation procedures compared to shorter ones, while the infusion rate decreased as the procedural stimulus decreased. Conclusion: According to the results of this study, no patients experienced adverse events during sedation, and all patients were kept at a moderate sedation level for a wide range of sedation times and differing procedures. The results showed that TCI pumps are safe and effective for administering propofol and remifentanil for moderate sedation in dentistry.

• Journal of Korea Water Resources Association
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• v.56 no.9
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• pp.587-602
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• 2023

Due to climate change, population growth, and economic development, the demand for water in the urban water system (UWS) and the energy required for water use constantly increase. Therefore, beyond the traditional method of considering only the water sector, the Nexus approach, which considers synergies and trade-offs between the water and energy sectors, has begun to draw attention. In previous researches, the Nexus methodology was used to demonstrate that the UWS is an energy-intensive system, analyze the water-energy efficiency relationship surrogated by energy intensity, and identify climate (long-term climate change, drought, type), geographic characteristics (topography, flat ratio, location), system characteristics (total supply water amount, population density, pipeline length), and operational management level (water network pressure, leakage rate, water saving) effects on the UWS. Through this, it was possible to suggest the direction of policies and institutions to UWS managers. However, there was a limit to establishing and implementing specific action plans. This study built the energy intensity matrix of the UWS, quantified the impact of city conditions, external influences, and operational management levels on the UWS using the water-energy Nexus model, and introduced water-energy efficiency criteria. With this, UWS managers will be able to derive strategies and action plans for efficient operation management of the UWS and evaluate suitability and validity after implementation.