• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.67-72
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• 2022

Concrete prevents corrosion of reinforcing bars due to its strong alkalinity. However, in the sea, strong alkali components with a pH of 12 to 13 are eluted, which adversely affects the ecological environment and growth of marine organisms. In this study, the mechanical properties and durability of the low alkali mortar were evaluated for the development of a low alkali mortar for the 3D printed artificial reefs. As a result of evaluation of strength characteristics, the α-35 mixture, which were produced with fly ash, silica fume and α-hemihydrate gypsum, satisfied the strength requirement 27 MPa in terms of compressive strength. As a result of pH measurement, it was found that mixing with alpha-type hemihydrate gypsum resulted in minimizing pH due to the the formation of calcium sulfate instead of calcium hydroxide production. As a result of the chloride ion penetration resistance test, the α-35 mixture exhibited the best performance, 3844C. As a result of measuring the length change over time, the α-35 mixture showed the shrinkage 33.5% less compared to the Plain mix.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.77-83
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• 2016

The electric quality of train is represented by voltage and current harmonics at PT(Ratio 25,000/15/[V]) which is located between pantograph and primary winding of train transformer. In this paper, voltage and current harmonics were measured on the test EMU(electric multiple unit)train with maximum speed of 180km/h in existing railway lines(chungbuk, Taeback, Honam). As a results of test, it is found that the electric quality of train depends on the mostly operation conditions which is accelerating mode and braking mode on each sections. Voltage THD is above all 3[%] and current harmonics is monitored from lowest Harmonic to highest Harmonic in case of accelerating mode. But, highest current harmonics is not monitored in case of breaking mode. The results in this paper can help to stabilize the power device and power converter of the test EMU train.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.11 no.1
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• pp.56-67
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• 1999

It is desired to use a domestically manufactured ocean data buoy for the long-term operational ocean monitoring. The ocean data buoy manufacturing technology was introduced through the research cooperation with the Qingkong University of Taiwan. The introduced ocean data buoy system was further expanded and improved for more efficient application for the marine environmental monitoring in Korea. The size of the ocean data buoy is 2.5 m in diameter, which is smaller compared to the NOAA's 3.0 m discus buoy to allow easy land transportation and ocean deployment as well. From the dynamic response test of the buoy carried out numerically, it was shown that the measurement of waves with period greater than 4 seconds is acceptable. The measurement and control system of the data buoy were improved to increase the number of measuring parameters, to reduce power consumption and to enhance better data analysis and management. Each component of the improved data buoy system was described in detail in this paper. Water quality sensors of water temperature, salinity, DO, pH and turbidity were added to the system in addition to the marine meteorological sensors of wind speed and direction, air temperature, humidity, air pressure and wave. Inmarsat satellite communication system is used for the real-time data telemetry from the buoy deployed offshore. A field performance test of the improved and domestically manufactured buoy was carried out for a month at the open sea off Pohang together with DatawelI's Wave-rider buoy to compare the wave data. The results of the test were satisfactory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.674-677
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• 2010

The purpose of this study was to analyze bradykinesia of forearm movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. A gyrosensor was selected for the measurement of forearm movement, because it can provide angular velocity signal which is free from the gravitational artifact and also because it can be conveniently used during clinical test of bradykinesia. Forty PD patients (age: $65.7\pm11.1$ yrs, H&Y stage:$2.3\pm0.5$), 14 age-matched elderly subjects ($65\pm3.9$ yrs) and 17 healthy young subjects ($24\pm2.1$ yrs) participated in this study. Angular velocity during forearm movement of pronation/supination was measured in both arms. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.05). This results suggest that PD patients can be differentiated from normal subjects using suggested measures.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.240-244
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• 2010

The purpose of this study is to compare finger tapping (FT) movement of patients with Parkinson's disease (PD) with normal subjects. A gyrosensor system was used for the measurement of FT movement, because it provides angular velocity free from the gravitational artifact and it can be used during clinical FT test listed in unified PD rating scale (UPDRS). Forty PD patients (age: 65.7 ${\pm}$ 11.1 yrs, H&Y stage:2.3 ${\pm}$ 0.5), 14 age-matched elderly subjects (65${\pm}$3.9 yrs) and 17 healthy young subjects (24${\pm}$2.1yrs) participated in this study. Angular velocity of finger tapping movement was measured in both right and left index finger. As quantitative measures, root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power were used. ANOVA showed that all measures were significantly different among three groups (p<0.001) in all quantitative measures. Post-hoc test revealed that all quantitative measures except peak power in patients with PD were significantly smaller than in both healthy elderly and young subjects (p<0.01). This suggests that the measures developed in this study can distinguish patients with PD from normal subjects.

• The Korean Journal of Pain
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• v.28 no.3
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• pp.198-202
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• 2015

Background: Lack of proper control of acute postoperative pain often leads to lingering or chronic pain. Several studies have emphasized the role of beta-blockers in reducing postoperative pain. Esmolol is a selective short-acting beta-blocker that produces few side effects. The purpose of this study was to examine the effect of intravenous intraoperative esmolol on postoperative pain reduction following orthopedic leg fracture surgery. Methods: In a clinical trial, 82 patients between 20-65 years of age with tibia fractures and American Society of Anesthesiologists (ASA) physical status I & II who underwent surgery were divided into two groups. Group A received esmolol and group B received normal saline. Postoperative pain was measured at three time points: entering the recovery unit, and at 3 h and 6 h following surgery, using the Visual Analogue Scale (VAS). A P value of < 0.05 was considered significant. Results: Mean VAS scores at all three time points were significantly different between the two test groups (P = 0.02, P = 0.0001, and P = 0.0001, respectively). The consumption of pethidine was lower in group A than in group B (P = 0.004) and the duration of its effect was significantly longer in time (P = 0.026). Conclusions: Intravenous intraoperative esmolol is effective in the reduction of postoperative pain following leg fracture surgery. It reduced opioid consumption following surgery and delayed patient requests for analgesics.

• The Korean Journal of Food And Nutrition
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• v.20 no.2
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• pp.150-157
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• 2007

Hamcho(Salicorinia herbacea, glasswort), a halophyte, is an annual succulent shrub that grows on coastal wetlands and has been regarded as a functional food for good health. Natural dried red and green Hamcho were extracted with 25% ethanol and water at 70$^{\circ}C$. The antioxidant activities of these four extracts were examined by six different assays, including the measurement of total phenolics, radical scavenging effects on 1,1-diphenyl-2-picrylhydrazyl(DPPH), nitric oxide(NO) and nitrite(NO$_2$) scavenging effects, reducing power, and the inhibitory effect on tyrosinase activity. The total phenolic contents of the four extracts were high at 237 ${\sim}$ 255 mg of gallic acid equivalents per 1 g of dried sample tested. The green Hamcho extracts contained more phenolic compounds than the red Hamcho extracts. When they were compared to tocopherols, the antioxidant activities of the green and red Hamcho powders were significantly higher at the same concentration levels(5 mg and 3 mg, respectively) in a POV test. The inhibition effects of the four extracts at a level of 75 ${\mu}l$ were higher than 98% in the POV test. The red Hamcho 25% ethanol extract showed a high significant effect on DPPH radical scavenging(SC$_{50}$, 90.1 ${\mu}l$). The green Hamcho 25% ethanol extract, however, showed a high significant effect on NO radical scavenging(SC$_{50}$, 6.1 ${\mu}l$). The NO$_2$ radical scavenging effect was assayed at pH 1.2, 4.2 and 6.0, and all the Hamcho extracts scavenged the NO$_2$ radical much more effectively at pH 1.2. The NO$_2$ scavenging effect of the red Hamcho 25% ethanol extract(64%) was as high as that of 5 mM vitamin C at pH 1.2(p<0.05). In the reducing power test, the red Hamcho 25% ethanol extract revealed the highest ferric ion reducing activity among the Hamcho extracts, and its activity was as high as that of 0.33 mg/ml of vitamin C. The four Hamcho extracts showed high tyrosinase inhibition effects of more than 80%, and their activities were higher than 50${\mu}$g of kojic acid. The green and red Hamcho 25% ethanol extracts totally inhibited tyrosinase activity(100%). Therefore, the results suggest that red Hamcho extracts may serve as useful natural antioxidants along with green Hamcho extracts.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.265-274
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• 2019

Delayed arrival of blood samples from the field and a large number of samples delivered often causes delay in sample analysis leading to inaccurate measurements. Therefore, this study aimed to assess whether prolonged storage in refrigerator could influence the stability of cattle blood samples and to establish an optimal time limit for complete blood count (CBC) parameters and blood gas and electrolyte (BGE) parameters analyses. Samples collected from healthy cows were tested immediately for CBC and BGE using automated hematology, blood gas and electrolyte analyzers. Samples were kept in refrigerator at 4℃ and analyzed after 6 h, 12 h, 24 h, 48 h, 72 h, 120 h, and 192 h of storage. Mean differences between observations were assessed at 5% significance level using ANOVA and Duncan's multiple range test. Total CBC parameters and the platelet profile remained stable for 192 h, except for MCHC. Among leukocyte-related counts, NEU and EOS remained stable for 192 hours. WBC and LYM, and MONO values produced inconsistent measurements which recovered its initial measurement after 12 h and 24 h of storage, respectively, then remained stable until 120 h. Among the blood gas indices, PCO₂, PO₂, tCO₂, and BE showed declining and significant changes over time, but pH, tHb, and SO₂ remained stable for 192 h. Electrolyte status in the blood showed that ions are unstable and tend to change in as early as 6 h of storage. This study established that cattle blood specimens for CBC analysis can be stored for 120 h at 4℃, but specimens for BGE analyses must be tested within 6 to 24 h.

• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.921-928
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• 2014

This study investigated the quality characteristics of cookies containing capsaicin, the main source of spicy taste in pepper, which is well known for its various functions such as anti-oxidant, anti-cancer, anti-inflammatory, and anti-obesity activities, as well as pain-relief effect. Cookie samples were made by adding the capsaicin powder at different levels, including 40 mg% (C1), 85 mg% (C2), and 150 mg% (C3). In this study, measurement of the moisture, pH, color, spread factor, hardness, anti-oxidant activity, and sensory evaluation of the cookies was carried out. The results showed that the anti-oxidant activity increased when more capsaicin powder was added to the cookies (p<0.001). The moisture also increased with increasing capsaicin powder content (p<0.05), while the pH did not show any significant changes. As for the colors, the L value and b value decreased as more capsaicin powder was added, while the a value increased. The spread factor also increased significantly with the increase of capsaicin powder (p<0.01). Although the hardness increased with capsaicin powder content, no statistically significant differences were observed among the various cookies. In the sensory evaluation, Cookies containing 40 mg of capsaicin obtained the highest score in color, while cookies containing 150 mg of capsaicin showed the highest score in taste, texture, and overall acceptability.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.270-272
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• 1997

In order to a study on the electrical properties of silicone gel due to the curing condition, the volume resistivity test is researched. For experiment, we have made up several samples of different curing temperature and time such as 1[H], 2[H] at 125[$^{\circ}C$], 150[$^{\circ}C$], 160[$^{\circ}C$], 170[$^{\circ}C$], 180[$^{\circ}C$]. A measurement of volume resistivity using the VMG-1000 highmegohm meter is recorded after 10 minutes when the each voltage, and DC 500[V] and 1000[V] is applied. A coaxial cylindrical liquid electrode to measure volume resistivity of specimen is used, and its geometric capacitance is 2[pF]. As a result of the experiment, the electrical properties of specimen cured at 170[$^{\circ}C$] for 2[H] is superior.