• Childhood Kidney Diseases
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• v.14 no.1
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• pp.32-41
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• 2010

Purpose : Glomerulonephropathy (GN) often manifests as proteinuria and progresses to chronic renal failure without specific therapy. Mesenchymal stem cell (MSC) has been tried as a therapeutic agent in experimental GN, and previous studies showed that administration of MSC concomitantly to the insult inducing GN or via intra-renal administration ameliorated proteinuria. The purpose of this study was to test the therapeutic potential of MSC administered via intravenous route at the time of clinically evident proteinuria. Methods : MSCs were administered intravenously via tail vain into the mice with adriamycin (ADR) induced nephropathy (ADR-GN), two weeks after ADR injection when massive proteinuria was evident. To test the capacity of MSC modulate the cytokine production in the inflammatory milieu, the concentrations of IFN-$\gamma$ and IL-10 were measured in the supernatant of in vitro mixed lymphocyte culture (MLC) with or without additional MSC. Results : MSCs administered intravenously into the proteinuric mice with ADR-GN accelerated the recovery of this experimental GN with disappearance of proteinuria in two weeks when the saline treated (control) mice still showed significant proteinuria. The mice treated with MSC also had a tendency of better survival. Addition of MSC decreased IFN-$\gamma$ and increased IL-10 in the supernatant of MLC. Conclusion : This study showed that MSC had a therapeutic potential even when administered in a more clinically relevant setting into a proteinuric glomerulonephropathy model. Further study to verify the mechanism and long-term safety of this phenomenon is required.

• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.40-45
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• 2019

This paper is a purpose to study the failure example for heavy-duty vehicle fire. The first example, the researcher found the engine over-heating phenomenon causing a coolant leakage by the sealing poor of head-gasket because of D-ring part deformation contacting with cylinder liner top-part and cylinder head. He certified a fire breakout by short transferred to surrounding wiring of air-cleaner. The second example, a brake lining by return fault of break operating S cam causing with much wear of a rear 4 wheel brake lining repeatably was worn by friction. In the long run, it became the cause of fire. The third example, the researcher knew the fire cause was came about the short of wire by overload of tilting motor when the driver tilted up the cap to inspect a engine. Therefore, a heavy-duty fire must minimize the fire occurrence by thorough controlling.

• Journal of the Korean Solar Energy Society
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• v.39 no.1
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• pp.59-66
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• 2019

BIPV or BAPV installation applied to building is increasing through public utility mandates enterprise. Solar PV energy generates only during the day, but if it is operated in convergence with ESS, which stores electrical energy, it can restrain the fossil energy used in buildings throughout the day. A solution is to converge with PV system and ESS. However, PV systems and ESS connected to the power grid in parallel can cause problems of electrical stability. A study was conducted on the case of failure to detect islanding operation under the parallel operation of PV generation and ESS that are connected in parallel to power grid. Experiments conducted various non-islanding detections under the operating conditions. In the experiment results, when one PCS - PV inverter or ESS inverter - was operating under the islanding condition, it stopped working within 0.5 seconds of the Korean grid standard. However, when both of PV inverter and ESS inverter were operating at the same time under the islanding situation, the anti-islanding algorithm did not operate normally and both inverters continuously supplied power to the connected RLC loads. islanding detection Algorithm developed by each inverter manufacturer has caused this phenomenon. Therefore, this paper presented a new test standard for islanding detection.

• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.589-601
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• 2022

Although drought is a natural phenomenon, its damage occurs in combination with regional physical and social factors. Especially, related to the supply and demand of various waters, drought causes great socio-economic damage. Even meteorological droughts occur with similar severity, its impact varies depending on the regional characteristics and water supply system. Therefore, this study assessed regional drought risk considering regional socio-economic factors and water supply system. Drought hazard was assessed by grading the joint drought management index (JDMI) which represents water shortage. Drought vulnerability was assessed by weighted averaging 10 socio-economic factors using Entropy, Principal Component Analysis (PCA), and Gaussian Mixture Model (GMM). Drought response capacity that represents regional water supply factors was assessed by employing Bayesian networks. Drought risk was determined by multiplying a cubic root of the hazard, vulnerability, and response capacity. For the drought hazard meaning the possibility of failure to supply water, Goesan-gun was the highest at 0.81. For the drought vulnerability, Daejeon was most vulnerable at 0.61. Considering the regional water supply system, Sejong had the lowest drought response capacity. Finally, the drought risk was the highest in Cheongju-si. This study identified the regional drought risk and vulnerable causes of drought, which is useful in preparing drought mitigation policy considering the regional characteristics in the future.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.53-64
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• 2009

Many slope failures are induced by rainfall infiltration. A lot of recent researches are therefore focused on rainfall-induced slope instability and the rainfall infiltration is recognized as the important triggering factor. The rainfall infiltrates into the soil slope and makes the matric suction lost in the slope and even the positive pore water pressure develops near the surface of the slope. They decrease the resisting shear strength. In Korea, a few public institutions suggested conservative slope design guidelines that assume a fully saturated soil condition. However, this assumption is irrelevant and sometimes soil properties are misused in the slope design method to fulfill the requirement. In this study, a more relevant slope stability evaluation method is suggested to take into account the real rainfall infiltration phenomenon. Unsaturated soil properties such as shear strength, soil-water characteristic curve and permeability for Korean weathered soils were obtained by laboratory tests and also estimated by artificial neural network models. For real-time assessment of slope instability, failure warning criteria of slope based on deterministic and probabilistic analyses were introduced to complement uncertainties of field measurement data. The slope stability evaluation technique can be combined with field measurement data of important factors, such as matric suction and water content, to develop an early warning system for probably unstable slopes due to the rainfall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.635-647
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• 2006

Korean construction companies first advanced to the international markets in 1960's and so far have brought more than 4,900 projects which account for 193 billion dollars approximately. With the large increase of national employment and income being followed by the achievement, Korea's construction industry has made an enormous contribution to the improvement of domestic economy for the last 40 years. However, recently the increased risk in international markets as well as the sharpening competition with foreign companies promising in terms of advanced technologies and low labor cost have been driving Korean construction away from the market shares. According to ENR (Engineering News Record, 1994~2003), it is revealed that 15.1% of top 225 global contractors are suffering from loss in international construction markets. This phenomenon is largely due to the highly uncertain characteristics of international projects, which are inherently exposed to various and complicated risky situations. Furthermore, especially for Korean construction companies, it is often the case that the failure in an international construction project cannot be offset by even a sufficient number of successful domestic achievements. Therefore, not only the selective screening among the nominated projects which have strong possibility of collapse but the systematic strategies for controlling potential risk factors are also considered indispensable in international construction portfolio management. The purpose of this study is to first analyze the causal relationships of the profit-influencing variables and the project success, and develop the profitability forecasting model in international construction projects.

• Development and Reproduction
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• v.12 no.1
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• pp.57-66
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• 2008

Changes in luteinizing hormone (LH), serum testosterone (T), and salivary T levels with age were examined in Korean men. Serum was obtained from 167 Korean men of different ages ($20{\sim}69\;y$), and the serum LH and T levels were measured. Saliva samples were also obtained, and the salivary T level was determined. The LH levels did not change considerably until 40 y of age (20s, $2.5{\pm}1.0$; 30s, $2.7{\pm}1.5$; and 40s, $2.5{\pm}1.8\;mIU/mL$) but increased significantly around 50 y (50s, $3.7{\pm}1.8$ and 60s, $3.1{\pm}1.7\;mIU/mL$). Further, the serum T levels also did not change until 40 y of age (20s, $5.3{\pm}2.6$, 30s, $4.4{\pm}1.4$, 40s, $4.1{\pm}1.5\;ng/mL$) but decreased significantly at 50 y (50s, $3.4{\pm}1.5$; 60s, $2.6{\pm}0.8\;ng/mL$). The salivary T levels also showed small changes until the age of 40 y ($20s{\sim}40s$, $0.11{\pm}0.015\;ng/mL$) but decreased significantly at 50 y ($0.08{\pm}0.03\;ng/mL$). Thus, the relative ratio of salivary T to serum T levels did not change significantly in all the ages examined ($2.4{\pm}0.9%$). Linear regression analysis predicted that the LH levels increased 1.5%/y while the serum and salivary T levels decreased 1%/y and 0.8%/y, respectively. The serum T/LH ratio did not change considerably until the age of 40 y ($20s{\sim}40s$, $2.27{\pm}0.14$) but decreased significantly ($1.2{\pm}1.0$) at 50 y. Age-related changes in the salivary T/LH ratio were very similar to those in the serum T/LH ratio. These results demonstrated that LH and T levels in serum or saliva did not change considerably until 40 y of age; instead, in Korean men, from 50 y of age, the LH level increased, while the T level decreased. This suggests that primary testicular failure that occurred due to aging (approximately 50 y) and caused this phenomenon. The present study also shows that the salivary T level can be an indicator of the free T level in serum although the salivary T level correlates weakly with the total T level in serum (r=0.53). Thus, information regarding salivary T levels may be useful for studying the age-related changes occurring in male testicular physiology.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.6 no.1
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• pp.78-95
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• 1999

The grafting of a kidney has been found to be the best medical treatment for patients who have renal insufficiency failure, but the patients still have experienced much trouble and apprehension. This study was done to further nursing theory developing for patients who have has a kidney graft from another person. The research method followed grounded theory methodology of Strauss and Corbin. The subjects were three female and four male patients. This study done befween Oct. 1997 and Mar. 1998. All of the subjects were interviewed by the author. Interview were done by the long interview technique and observation. In the process of data analysis, 'heart-boiling' was found to be the core phenomenon. The results were composed to 101 concepts. These concepts were grouped into nineteen categories, and then to twelve categories. There were 12 super-class categories as follows ; 'pain', 'heart-boiling', 'experience of dialysis', 'term of admission to a hospital', 'support of other person', 'dependence on God', 'direction', 'negative reaction', 'positive reaction', 'comfortable', 'lacking', 'acceptance'. In this process, 14 hypotheses were derived from the categories as follows ; (1) The more experience with dialysis that the patients have, the stronger the heart-boiling will tend to be. (2) The less experience with dialysis the patients have, the weaker the heart-boiling will tend to be. (3) The longer admission to hospital the patients have, the stronger the heart-boiling will be. (4) The shorter the admission to hospital the patients have, the weaker the heart-boiling will be. (5) The weaker the intense-grief is, the more positive the reaction to heart-boiling the patients wll have. (6) The stronger the intense-grief is, the more negative the reaction to heart-boiling the patients will have. (7) The stronger the support of other persons that the patients have, the more positive the reaction to heart-boiling the patients will have. (8) The weaker the support of other person that the patients have, the more negative the reaction to heart-boiling the patients will have. (9) The stronger the dependence on God that the patients have, the mure positive reaction to heart-boiling the patients will have. (10) The weaker the dependence on God that the patients have, the more negative reaction to heart-boiling the patients will have. (11) The more positive thoughts that the patients have, the more positive reaction to heart-boiling the patinets will have. (12) The more negative thoughts that the patients have, the more negative reaction to heart-boiling the patients will have. (13) The more positive reaction the patients have, the more free from heart-boiling the patients tend to be. (14) The more negative reaction the patients have, the less free from heart-boiling the patients tend to be. From the analysis of observed data and comparing each class, I concluded that there are four formula relation types between reaction of patients and heart-boiling. (1) If patients have the experience of dialysis, have a long term admission to hospital, are strong in heart-boiling, depend on God, have positive thoughts and another's strong support, they experience release by positive reaction to the intense-grief. (2) If patients have the experience of dialysis, have a short term admission to hospital, are weak in heart-boiling, do not depend on God, have negative thoughts, and have few supports from others, they experience attachment to heart-boiling though a negative reaction. (3) If patients have the experience of dialysis, have a long term admission to hospital, are strong in heart-boiling, do not depend on God, and have negative thoughts, they experience attachment to heart-boiling through negative reaction in spite of support from another. (4) If patients have the experience of dialysis, have a long term admission into hospital, are strong in heart-boiling and satisfaction is low, but they have positive thoughts, then they experience acceptance and harmony through the positive reaction to heart-boiling. The results of this study are expected to help the way nurses care for patients who have had a kidney graft from another.

• Korean Security Journal
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• no.41
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• pp.37-66
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• 2014

In recent years, with the development of computers and electronics, electronics and communication technology in a growing and each part is dependent on the cross-referencing makes all electronic equipment is obsolete due to direct or indirect damage EMP. Korea and the impending standoff North Korea has a considerable level of technologies related to the EMP, EMP weapons you already have or in a few years, the development of EMP weapons will complete. North Korea launched a long-range missile and conducted a nuclear test on several occasions immediately after, when I saw the high-altitude nuclear blackmail has been strengthening the outright offensive nuclear EMP attacks at any time and practical significance for the EMP will need offensive skills would improve. At this point you can predict the damage situation of Korea's security reality that satisfy the need, more than anything else to build a protective system of the EMP. The scale of the damage that unforeseen but significant military damage and socio-economic damage and fatalities when I looked into the situation which started out as a satellite communications systems and equipment to attack military and security systems and transportation, finance, national emergency system, such as the damage elsewhere. In General, there is no direct casualties reported, but EMP medical devices that rely on lethal damage to people who can show up. In addition, the State power system failure due to a power supply interruption would not have thought the damage would bring State highly dependent on domestic power generation of nuclear plants is a serious nuclear power plant accident in the event of a blackout phenomenon can lead to the plant's internal problems should see a forecast. First of all, a special expert Committee of the EMP, the demand for protective facilities and equipment and conduct an investigation, he takes fits into your budget is under strict criteria by configuring the contractors should be sifting through. He then created the Agency for verification of performance EMP protection after you have verified the performance of maintenance, maintenance, safety and security management, design and construction company organized and systematic process Guard facilities or secret communications equipment and perfect for the EMP, such as protective equipment maneuver system should take.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.863-870
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• 2016

We investigated the physical/chemical phenomena that a slow loss of $CO_2$ inventory into sodium after the sodium-$CO_2$ boundary failure in printed circuit heat exchangers (PCHEs), which is considered for the supercritical $CO_2$ Brayton cycle power conversion system of a sodium-cooled fast reactor (SFR). The first phenomenon is plugging inside narrow sodium channels by micro cracks and the other one is damage propagation referred to as wastage combined with the corrosion/erosion effect. Experimental results of plugging shows that sodium flow immediately stopped as $CO_2$ was injected through the nozzle at $300{\sim}400^{\circ}C$ in 3 mmID sodium channels, whereas sodium flow stopped about 60 min after $CO_2$ injection in 5 mmID sodium channels. These results imply that if pressure boundary of sodium-$CO_2$ fails a narrow sodium channel would be plugged by reaction products in a short time whereas a relatively wider sodium channel would be plugged with higher concentration of reaction products. Wastage by the erosion effect of $CO_2$ (200~250 bar) hardly occurred regardless of the kinds of materials (stainless steel 316, Inconel 600, and 9Cr-1Mo steel), temperature ($400{\sim}500^{\circ}C$), or the diameter of the $CO_2$ nozzle (0.2~0.8 mm). Velocities at the $CO_2$ nozzle were specified as Mach 0.4~0.7. Our experimental results are expected to be used for determining the design parameters of PCHEs for their safeties.