• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.191-202
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• 2001

Experiments were conducted on established grassland sward at Gongiam, Kwangju, and Kyung-gi in Korea from 1995 to 1997. The influence of mineral-N fertilizer or animal manure(AW) on herbage dry matter(DM) yield, N yield, the recovery of AM-N, and soil N and organic matter(0M) content in the mixed sward('potomac' orchardgrass, 'fawn' tall fescue, and 'kenblue' Kentuky bluegrass) was investigated. The treatments were replicated three times in a split plot block design. AM(the main plots) was applied at 200kg N ha ' year ' on each plot. The types of AM were cattle feedlot manure(CFM), pig manure fermented with sawdust(PMFS) and Korea native cattle slurry(KNCS). Three levels of mineral-N fertilizer, as urea, ranging from 0 to 200kg N $ha^{-1}\;year^{-1}$ in 100kg increments, were superimposed on each plot. The fertilizers and AM were applied in two equal dressings(the end of March and middle of November). AM and mineral fertilizer had significant effects(p<0.05) on herbage DM and N yields. Herbage yields in KNCS were higher than those in CFM and PMFS(p

• Journal of Power Electronics
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• v.15 no.6
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• pp.1489-1498
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• 2015

Gallium nitride (GaN)-based power switching devices, such as high-electron-mobility transistors (HEMT), provide significant performance improvements in terms of faster switching speed, zero reverse recovery, and lower on-state resistance compared with conventional silicon (Si) metal-oxide-semiconductor field-effect transistors (MOSFET). These benefits of GaN HEMTs further lead to low loss, high switching frequency, and high power density converters. Through simulation and experimentation, this research thoroughly contributes to the understanding of performance characterization including the efficiency, loss distribution, and thermal behavior of a 160-W GaN-based synchronous boost converter under various output voltage, load current, and switching frequency operations, as compared with the state-of-the-art Si technology. Original suggestions on design considerations to optimize the GaN converter performance are also provided.

• Journal of Chest Surgery
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• v.30 no.9
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• pp.847-853
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• 1997

Although the effects of adenosine on the heart, including the clinical suppression of cardiac arrhythmias, have been recognized for more than half a century, it is only in the last decade that the therapeutic potential of adenosine has been recognized. The objective of this study was to determine if augmentation of myocardial adenosine levels during global ischemia improves functional recovery after reperfusion. We used to modified Langendonf system to evaluate myocardial protective effect. Isolated rat hearts were subjected to 90 minutes of deep hypothermic arrest(15$^{\circ}C$) with modified St. Thomas'Hospital cardioplegic solution used to provide myocardial protection. Myocardial adenosine levels were augmented during ischemia by providing exogenous adenosine in the cardioplegic solution. Two groups of hearts w re studied: (1) control group(n=10) cardioplegia alone; (2) adenosine group(n=10) adenosine(0.75mg/kg/min) added to the cardioplegic solution. Significantly better percent recovery(p<0.01) in hemodynamics(except heart rate) at 60 minutes after reperfusion was evident compared to baseline values in the adenosine group. (systolic no란ic pressure : 78.5$\pm$3.6% vs 66.6$\pm$5.9%, airtic overflow volume : 61.7$\pm$ 11.6% vs 37.2$\pm$ 15.4%, coronary flow volume 77.1$\pm$7.5% vs 57.2$\pm$ 11.1%, and cardiac output : 65.6$\pm$ 11.5% vs 44.2$\pm$ 12.4%). Heart rate was similar in two groups(94.4$\pm$4.8% vs 95.3 $\pm$ 6.8%). Adenosine groups resulted in significantly rapid recovery time of heart beat after reperEusion(p<0.01) (24.5$\pm$7.6 sec. vs 179.0$\pm$ 131.1sec.). In biochemical study, CPK levels(0.1 $\pm$0.3U/L vs 1.4$\pm$0.8U/L) and lactic acid levels(0.08$\pm$0.Immol/L vs 0.34$\pm$0.2 mmol/L) were significantly low in adenosine groups(p<0.01). We concluded that adenosine included cardioplegia have better recovery effects after r perfusion in myocardial ischemia compared to adenosine free cardioplegia.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.409-419
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• 2022

The purpose of this study was to investigate how the increased sedentary behavior due to COVID-19 on physical factors to maintain health. The subjects of the study were 33 office women who mainly lead a sedentary behavior. The group settings were divided into high sedentary behavior groups(n=11), middle sedentary behavior groups(n=11), and low sedentary behavior groups(n=11) according to the hours of sitting down living. There was no significant difference between the groups in the VO₂max and EPOC, the level of lactate in blood showed a significant difference immediately after exercise(p<.05) and at 15(p<.001) and 20(p<.001) minutes of recovery, and the degree of recovery was more smooth in the low sedentary behavior groups. These results suggest that the difference in time according to the degree of sedentary behavior will affect the factors for maintaining health. Therefore, it is considered necessary to minimize sedentary behavior time even in the COVID-19 situation where the time spent in a personal space increases.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 1993.03a
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• pp.14.2-15
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• 1993

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.93-99
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• 2001

This study aims at finding out pertinent reaction conditions for treating high concentration ammonia contained in N-chemical factory wastewater with decompressed ammonia stripping method that was designed. And it also tries to investigate adsorption capability of removed ammonia to soil. The results from experiments are as follows ; 1. The removal rate of N $H_3$-N of synthetic wastewater was under 85% at pH 10 with decompressed ammonia stripping method. The reaction time in pressure 360 mmHg at pH 11 and 12 was shorter than in 460 mmHg, and the removal rate of N $H_3$-N with decompressed ammonia stripping method at 9$0^{\circ}C$ was 11~15% higher than air stripping 2. The optimum conditions for decompressed ammonia stripping with synthetic sample were shown as pH 12, temperature 9$0^{\circ}C$, internal reaction pressure 460 mmHg and reaction time 50 minutes. These conditions were applied to treat the wastewater containing organic-N 290.5mg/$\ell$, N $H_3$-N 168.9mg/$\ell$, N $O_2$-N 23.2mg/$\ell$, N $O_3$-N 252.4mg/$\ell$, T-N 735mg/$\ell$. Organic-N turned out to be removed 60%, the removal rate of N $H_3$-N IS 94%, T-N is 50%. But N $O_2$-N and N $O_3$-N were increased with 7.8% and 14.9% respectively. 3. The CO $D_{Sr}$ removal rate in decompressed ammonia stripping reaction was 42% and S $O_4$$^{2-}$ was removed 8.2%. It was turned out caused with higher pH and thermolysis. 4. In soil adsorption of ammonia desorbed from the decompressed stripping process of wastewater, the recovery rate was 76% in wet soil.

• Korean Journal of Materials Research
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• v.13 no.10
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• pp.673-676
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• 2003

We have investigated $Al_{x}$ $Ga_{l-x}$ N/GaN epilayers (x = 0.08, 0.15) grown by metal organic vapor phase epitaxy on sapphire with photoluminescence(PL), and persistent photoconductivity(PPC) experiments. An anomalous S-shaped shift behavior of temperature dependencies of PL peak energy is observed for the x = 0.15 sample. In PPC measurement, showed that the dark current recovery time of $Al_{x}$$Ga_{l-x}$ N/GaN epilayers mainly depends on the Al content. These behaviors are usually attributed to the presence of carrier localization states. All these phenomena are explained based on the alloy compositional fluctuations in the $Al_{x}$ /$Ga_{l-x}$ N/ epilayers. The photocurrent quenching observed in PPC measurements for $Al_{x}$ $Ga_{l-x}$ N/ epilayers less than 0.2 $\mu\textrm{m}$ thickness indicates that the presence of metastable state in the bandgap of GaN layer, and that the excess holes in the valence band recombine with free electrons.

• The Journal of Korean Physical Therapy
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• v.26 no.4
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• pp.240-248
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• 2014

Purpose: The purpose of study was to determine the effects of muscle reeducation training in patients with acute facial nerve paralysis. Methods: Thirty patients were randomly assigned to either the experimental group (n=15) or the control group (n=15). The experimental group received muscle reeducation training for 20 minutes after electrotherapy and the control group received conventional electrotherapy for only 40 minutes. Therapeutic intervention for each group was performed four times per week for four weeks. The patients were measured for recovery of paralysis using the House-Brackmann Grading System (H-B grade), the Movement Distance of Mouth, Nasolabial Angle (NA), and Facial Disability Index (FDI). Results: In within group comparison, the experimental group showed significant improvements for all variables (p<0.01). In comparison between two groups, the experimental group showed relatively greater significant improvements for all variables (p<0.01). Conclusion: These findings suggest that muscle reeducation training is more effective than conventional therapy in improving the condition of patients with facial nerve paralysis. In particular, the results of this study indicate that muscle reeducation training can be recommended by clinicians since it provides more benefits.

• Development and Reproduction
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• v.23 no.2
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• pp.183-191
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• 2019

The objective of this study is to evaluate the anesthetic effects of clove oil and tricaine methanesulfonate (MS-222) on the Far Eastern catfish, Silurus asotus, by measuring the times to anesthesia and recovery. Each anesthetic effect of clove oil and MS-222 was tested in two groups of fish with different body sizes: a group of small fish (mean body length: $15.5{\pm}1.58cm$, mean body weight: $50.1{\pm}5.91g$, n=20) and a group of large fish (mean body length: $31.5{\pm}4.19cm$, mean body weight: $302.1{\pm}15.22g$, n=20). The anesthetics were used at concentrations of 200, 300, 400, 500, and 600 ppm. The results showed significant relationships between the concentration of the anesthetic and the body size of the fish. Each of these variables showed statistical significance (p<0.05). The time to anesthesia decreased linearly with increasing concentration in the large fish for both clove oil and MS-222 (p<0.05). Based on an optimal anesthetic time of approximately 1 min, the preferred concentrations of the anesthetics were 500 ppm for clove oil and 600 ppm for MS-222. Both the anesthetic time and the recovery time were shorter for the small fish than for the large fish (p<0.05). Our study showed that the smaller-sized Far Eastern catfish was more easily anesthetized and recovered more rapidly from anesthesia than the larger-sized fish.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.132-136
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• 2002

The rice straw managements are essential for maintaining soil fertility as well as reducing chemical fertilizer application in paddy field. A field experiment was conducted on moderately well draining alluvial paddy soil to investigate the decomposition pattern of rice straw. The mesh bags containing the rice straw harvested in the previous year were placed at soil surface and buried into around 10cm depth and recovered periodically for determining the straw decomposition. Pot experiments were conducted to investigate the fates of N released from $^{15}$ N-labeled rice straw under different levels of N fertilizer application. The overall decomposition patterns of rice straw were similar for the two incorporation depths in transplanted paddy field. The straw incorporated at transplanting date showed weight loss of about 50%, 70% and 90% after 2 months, 5 months, and 2 years, respectively. The decompositions of straw cell wall components showed somewhat different pattern. The decompositions of cellulose and silica were similar to that of dry weight while the decomposition of lignin was slower than that of cellulose and silica. N was released from rice straw 42% and 65 % of the initial N after one month and after five months, respectively. P release was faster than N release. Recoveries of rice straw-$^{15}$ N by rice plants were 10.2, 13.4 and 14.9% in 0, 120 and 240 mg N pot$^{-1}$ , respectively. Soil recoveries of rice straw $^{15}$ N were 17.3, 20.6 and 18.9% in 0, 120 and 240mg N pot$^{-1}$ , respectively.