• 한국지반환경공학회 논문집
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• 제7권1호
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• pp.5-18
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• 2006

쇄석말뚝과 조립토 다짐말뚝은 연약지반의 보강, 극한지지력의 증대 및 기초 지반의 압밀을 가속화시키기 위한 목적으로 지난 수십 년 동안 폭넓게 사용되고 있다. 조립토 다짐말뚝의 극한지지력은 조립토 말뚝의 팽창파괴를 억제하기위한 지반의 횡방향 구속압에 지배된다. 한편, 조립토 다짐말뚝은 충분한 횡방향 구속압이 발휘되지 못하는 압축성 점토지반이나 연약지반에서는 그 기능을 기대하기 어려운 점이 있다. 따라서 본 연구에서는 기존 조립토 다짐말뚝과 일부 심도를 빈배합 콘크리트로 보강한 조립토 다짐말뚝에 대한 3차원 수치해석을 실시하여 그 결과를 비교, 분석하였다. 또한, 본 연구에서는 수치해석결과를 바탕으로 침하저감계수에 대한 회귀분석식이 제시되었으며, 침하저감계수에 대한 변수분석을 통해 제안된 침하저감계수 회귀식의 타당성을 검증하였다.

• 대한의생명과학회지
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• 제9권2호
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• pp.85-91
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• 2003

Gentiana scabra var. buergeri (G. scabra) is a herb known to have therapeutic effect in infection diseases. We studied cellular activation and antitoxoplasmosis in macrophages after G. scabra stimulation. Macrophage activation was detected by nitrite production. Macrophages were treated with G. scabra extracted with water or methanol. Maximal nitrite production was detected in macrophages after stimulation of G. scabra extract 0.1 mg/ml. Maximal nitrite concentration was 23.22 0.003 uM/L in macrophages after water extract of G. scabra and was 24.07 1.41 uM/L after methanol extract of G. scabra. Effect of G. scabra in the phagocytic capacity of macrophages was monitored by using PI (percentage of macrophage infected by T gondii) method. The minimum PI (42.5 2.31) was detected in macrophages treated by water extract of G. scabra 0.1 mg/ml before infection of T gondii. We also examined toxoplasmastatic capacity of macrophage using FI (fold increase) method. The minimum FI (4.46 1.16) was shown in macrophages after water extract of G. scabra 0.1 mg/ml pretreatment before infection. Under electron microscope, proliferation of T gondii was inhibited by extract of G. scabra treatment in macrophages and the mitochondrion and lysosomal vacuoles within cells were increased. Taken together, G. scabra extract activates macrophages and induces toxopalsmastatic activity after T gondii infection. It is suggested that G. scabra may be used as a therapeutic drug against toxoplasmosis.

• 한국토양비료학회지
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• 제50권6호
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• pp.554-561
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• 2017

Under the projected global warming, release of carbon as $CO_2$ through soil organic matter decomposition is expected to increase. Therefore, accurate measurement of $CO_2$ released from soil is crucial in understanding the soil carbon dynamics under increased temperature conditions. Sodium hydroxide (NaOH) traps are frequently used in laboratory soil incubation studies to measure soil respiration rate, but decreasing $CO_2$ gas solubility with increasing temperature may render the reliability of the method questionable. In this study, the influences of increasing temperature on the $CO_2$ capture capacity of NaOH traps were evaluated under $5{\sim}35^{\circ}C$ temperature range at $10^{\circ}C$ interval. Two closed-chamber experiments were performed where NaOH traps were used to capture $CO_2$ either released from acidified $Na_2CO_3$ solution or directly injected into the chamber. The sorption of ambient $CO_2$ within the incubators into NaOH traps was also measured. The amount $CO_2$ captured increased as temperature increased within 2 days of incubation, suggesting that increased diffusion rate of $CO_2$ at higher temperatures led to increases in $CO_2$ captured by the NaOH traps. However, after 2 days, over 95% of $CO_2$ emitted in the emission-absorption experiment was captured regardless of temperature, demonstrating high $CO_2$ absorption efficiency of the NaOH traps. Thus, we conclude that the influence of decreased $CO_2$ solubility by increased temperatures is negligible on the $CO_2$ capture capacity of NaOH traps, supporting that the use of NaOH traps in the study of temperature effect on soil respiration is a valid method.

• 대한통합의학회지
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• 제9권3호
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• pp.203-211
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• 2021

Purpose : It was to compare changes in respiratory function (pulmonary function, inspiratory function) after four weeks of inspiratory muscle strengthening training (diaphragmatic breathing with upper arm exercise, Power-Breathe breathing) for 36 healthy people. Methods : Subjects were randomly assigned to diaphragmatic breathing with upper arm exercise (Group I) and Power-breathe breathing (Group II) was conducted by the protocol for four weeks five times per week. As the main measurement method for comparison between groups For pulmonary function, Forced Vital Capacity (FVC) and Forced Expiratory Volume at One second (FEV1) were used, and for inspiratory function, Maximum Inspiratory Capacity (MIC), Maximum Inspiratory Pressure (MIP), and Maximum Inspiratory Flow Rate (MIFR) were used. Results : In changes in pulmonary function between groups, FVC and FEV₁ showed no significant difference, and in inspiratory function changes, MIC showed no significant difference, but in MIP and MIFR, Group B significantly improved over Group A. Conclusion : The progressive resistance training using the Power-breath device applied to the inspiratory muscle did not show a significant difference in the increase in the amount of air in the lungs and chest cage compared to the diaphragmatic breathing training accompanied by the upper arm exercise. However, by increasing the air inflow rate and pressure, it showed a more excellent effect on improving respiratory function.

• 한국병원경영학회지
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• 제20권3호
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• pp.13-23
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• 2015

This research is intended to inquire any discrepancy depending on the variables such as types, geography and size of hospitals of Korea in order to develop differentiated marketing strategy and to investigate how the aforementioned variables affect the management performance such as the increase in the number of foreign patients, their willingness to re-visit, the increase in profit and etc. The survey for this research was conducted for five weeks from July 10th 2014 to August 30th 2014 with 251 participants in charge of foreign patient attraction for 161 domestic hospitals. As the method of the research, a hypothesis was first established based on previous studies, followed by the incorporation of self-administered questionnaire to confirm the formulated hypothesis. Frequency analysis and ANOVA analysis were used to analyze the result of the survey. The outcome of the research and the implications are as follows. First, according to the demography of the persons-in-charge of foreign patient attraction, the proportion of female was superbly high by 76.5%. As for the age, those in their 30s were highest in proportion. Finally, for the education level, college graduates took up the largest portion by 46.5%. Second, in respect to the hypothesis assuming the difference in performance depending on the types of hospitals, national university-affiliated hospitals showed the highest level of the increase in foreign patients by the average of 3.25. Third, in respect to the hypothesis assuming the difference in performance based on geographical position, it was confirmed that hospitals in Ulsan City experienced the largest growth in the number in foreign patients. Fourth, in respect to the sizes of hospitals, those with 201 to 300 sickbeds showed the highest increase by the average of 3.45. The implication of the above research outcome indicates that while the number of foreign patients visiting Korea for medical purposes is on the rise, the number of professionals in place with necessary knowledge and capacity is insufficient and requires improvement.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.750-752
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• 2002

An HTS power cable has multi-layer conductor structure to increase the current capacity. However, usually the current is not evenly distributed among the layers. This paper describes a method to make the current distribution more uniform and hence reduce the AC loss. Also. this paper shows recommendation for future cable conductor prototypes.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.166-171
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• 2008

LNG carrier is a special-purpose vessel to transport natural gas (NG) from the place of origin to each consuming country. To increase the capacity of canying LNG carrier, the natural gas is conveyed as a state of liquid called LNG (Liquefied Natural Gas) during a voyage because the total volume of NG is surprisingly reduced when it is cooled down to $-162^{\circ}C$. That is why the design of insulation of the carriers is important to protect LNG from the external heat invasion, and it has been a great challenging subject for several decades in the shipbuilding industry. For this ultimate goal, the boil-off rate (BOR) needs to be accurately estimated during a voyage. Therefore, the goal of this study is to propose a numerical method for estimating the BOR of LNG for given insulation containment subject to external temperature conditions during voyage.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.685-689
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• 2017

We studied the removal of zinc ions from synthetic brackish water by an adsorption method using natural Algerian Bentonite (NAB). The effect of the main physico chemical parameters-contact time, pH, temperature, ionic strength, clay weight and initial metal ion concentrations on the removal of $Zn^{+2}$-were investigated. The results showed that equilibrium was attained within 10 min of stirring time. The retention capacity of $Zn^{+2}$ increased with the increase of pH, the adsorbent dose and ionic strength. A modelization study showed that the adsorption follows Langmuir isotherm, while its kinetics was pseudo-second-order. Based on the results, it was concluded that NAB, which is natural and available, could be used as an alternative for the removal of zinc from saline aqueous solutions.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권7호
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• pp.363-368
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• 1999

The parallel operation system of multiple uninterruptible power supplies(UPSs) is used to increase power capacity of the system or to secure higher reliability at critical loads. In the parallel operation of the two UPSs, the load-sharing control to maintain the current balance between them is a key technique. Because a UPS has low output impedance and quick response characteristics, in case of an unbalanced load inverter output current changes very rapidly and thereby can instantaneously reach an overload condition. In this study, high precise load-sharing controller is proposed and implemented for the parallel operation system of two UPSs with low impedance characteristics and this controller controls the frequency and the voltage to minimize the active power component and the reactive power component which are gotten from the current difference between two UPSs. And then a good performance of the proposed method is verified by experiments in the parallel operation system with two 40KVA UPSs.

• 설비공학논문집
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• 제14권12호
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• pp.1039-1046
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• 2002

To investigate the characteristics of orifice as an expansion devices, the experimental apparatus was made and experiments are being peformed using R22 and R290. The main idea of this control method of refrigerant flow rate with coupled orifices is to control the ON/OFF state of T and Ball type orifice corresponding to the subdivided region of thermal load. When system requires minimum thermal load, both T and Ball type orifices are closed, but refrigerant can flow through small hole of T type orifice. In regular thermal load, when ball type orifice is closed, T type orifice is opened and mass flow rate increase more than OFF state of T type orifice, due to large diameter. In maximum thermal load, both T and Ball type orifices are open and the much refrigerant can flow. The flow characteristics on T type orifice and parallel-combined orifice are obtained in the subdivided region of thermal load.