• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.3
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• pp.122-126
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• 2012

The properties of Al-doped ZnO (AZO) films were investigated as a function of $H_2/(Ar+H_2)$ gas ratio using an AZO (2 wt% $Al_2O_3$) ceramic target in a radio frequency (RF) magnetron sputtering system. The deposition process was done at $200^{\circ}C$ and in $2{\times}10^{-2}$ Torr working pressure and with various ratios of $H_2/(Ar+H_2)$ gas. During the AZO film deposition process, partial $H_2$ gas affected the AZO film characteristics. The electron resistivity (${\sim}9.21{\times}10^{-4}\;{\Omega}cm$) was lowest and mobility (${\sim}17.8\;cm^2/Vs$) was highest in AZO films when the $H_2/(Ar+H_2)$ gas ratio was 2.5 %. When the $H_2/(Ar+H_2)$ gas ratio was increased above 2.5 %, the electron resistivity increased and mobility decreased with increasing $H_2/(Ar+H_2)$ gas ratio in AZO films. The carrier concentration increased with increasing $H_2/(Ar+H_2)$ gas ratio from 0 % to 7.5 %. This phenomenon was explained by reaction of hydrogen and oxygen and additional formation of oxygen vacancy. The average optical transmission in the visible light wavelength region over 90 % and an orientation of the deposition was [002] orientation for AZO films grown with all $H_2/(Ar+H_2)$ gas ratios.

• Journal of the Korean GEO-environmental Society
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• v.13 no.9
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• pp.45-51
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• 2012

The calcium hydroxide$(Ca(OH)_2)$ which is the cement hydrate flowed into the tunnel by groundwater is reacted with microorganism in the soil, carbon dioxide$(CO_2)$ and the vehicle's exhaust gas$(SO_3)$. So its by-products are precipitated at the drainage pipe and these cause the drainage clogging. By this phenomenon, Degradation of water flow at the drainage system of the tunnel occurred and also pore water pressure is increased. Hence the acceleration of seepage and degradation of lining is occurred. The purpose of this study is to evaluate the field applicability of the Quantum Stick and Magnetic treatment in prevention of scale deposits at the Namsan ${\bigcirc}{\bigcirc}$ tunnel and the Zone ${\bigcirc}{\bigcirc}{\bigcirc}$ of subway. These technologies were installed into drainpipes with their performance monitored through occasional site visits. SEM and XRD were also performed on scale collected from these drainpipes. As a result, in case which factor technology is applied, scale creation is remarkably decreased and especially Quantum Stick treatment performing better than Magnetic treatment. Therefore, additional application of Quantum Stick or Magnetic treatment to the existing drainage is expected to decrease the drainage clogging of the drainage.

• Journal of Yeungnam Medical Science
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• v.24 no.2
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• pp.232-242
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• 2007

Background : The safety and efficacy of trabeculectomy with Mitomycin C (MMC) for surgical treatment in aphakic and pseudophaic eyes were retrospectively evaluated. Materials and Methods : The authors reviewed 51 eyes of 45 patients who had been followed up for at least 6 months after trabeculectomy using MMC for aphakic and pseudophakic eyes. The success rate and complications were analyzed. The success criteria included intraocular pressures of 21 mmHg or less with or without glaucoma medications and no loss of light perception. Surgical failure was defined as a postoperative loss of light perception in patients with preoperative vision better than light perception, additional glaucoma surgery, or phthisis bulbi in patients with preoperative vision of no light perception. Results : The average follow up period was 27.7 months and the intraocular pressure was controlled under 21 mmHg in 36 eyes of 51 (70.6%) after the procedure with or without medication for glaucoma. Using the Kaplan-Meier survival analysis, the cumulative success rate at the 3-, 6-, 12-, 24- and 36-month intervals were 98.0%, 94.1%, 91.9%, 83.4% and 75.5%, respectively. The complications observed were hyphema (4 eyes), serous choroidal detachment (4 eyes), hypotony (3 eyes), and endophthalmitis (1 eye). Conclusion : Trabeculectomy using Mitomycin C for the treatment of aphakic and pseudophaic eyes was safe and effective.

• Journal of Korean Academy of Nursing
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• v.27 no.2
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• pp.433-443
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• 1997

Cardiac catheterization is a diagnostic procedure which is intrusive and anxiety provoking. Patient education and information offer have been suggested as effective nursing interventions to reduce patients' anxiety and stress. Main objectives of this study are : 1) to develop concrete objective information for patients undergoing cardiac catheterization : 2) to analyze the types of information included in the newly developed concrete objective information. The subjects of this study are 11 patients who were admitted to the CCU of a general hospital in Seoul. The subjects were provided with preparatory information about cardiac catheterization by using interview and a booklet. After the procedure, the subjects were asked to describe additional information which they suggest to be added into the booklet and the physical sensations felt during the procedure. The results of the study are summarized as follows : Most subjects were satisfied with the preparatory information that was provided by interview and the booklet before the procedure. But patients suggested several problems related to the content of the booklet. First, they reported difficulty to differentiate the terms -coronary angio gram and cardiac catheterization. Also, some patients expressed that they feared after reading the information about the incision of inguinal area. Subjects responded that the information about the direct process of the test did not reduce their anxiety and the information was not detail enough. Next, most subjects would want to know about the monitor and the sound from monitor. They said that they could not hear instructions from doctor or nurse during the procedure due to tension. Considering above response results, the need for more effective way to provide information, like visual and auditory information through video tape for giving information is suggested. Sensations related to the procedure were the smell coming from sterilization of inguinal area, stinging pain in groin when the doctor inserts a needle into artery, and the sensation of pressure and moving of vessels surrounding neck when the catheter was inserted and visualized on fluoroscopy. Besides, subject reported hot sensation and burning feeling in face and chest area, and nausea when dye is injected by hand. In the analysis of information content, there was 79% agreement on the actual units of analysis that were coded. In the analysis of type of information, procedural information was 60.4%. Concrete objective information was 28.1%. and other information was 11.5%. Agreement of the coders in categorizing the units of information was determined by using Cohen's kappa which corrects for chance agreement. Cohen's kappa was .84.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.41-52
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• 2017

This research conducted the two types of model tests to examine the failure parameters by levee overflow, those were the pilot-scale levee (model height 0.4~0.8 m) and real scale levee (model height 1.0 m). The procedure of levee failure by overflow was succeeded to the following three steps: At first step, the local scouring on levee slope was happened and the overflow velocity was increased slowly. At second step, the enlarged scouring surface and the rapid overflow velocity were succeeded. At last, the levee section was broken totally and the overflow velocity was decreased because of the wide failure surface of levee. The levee failure angle (${\theta}$) was appeared bigger than slope failure angle of Rankine earth pressure. The enlarged levee height (H) made the faster overflow velocity (${\upsilon}$) of the levees, therefore additional tractive force was applied to it, futhermore the failure angle (${\theta}$) and failure surface (A) were enlarged. Because the sand sample for pilot-scale and real scale tests had the same diameter, the critical scouring velocity of each type was also the same, and the scouring properties were governed by variation of overflow velocity.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.515-523
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• 2000

Polymorphonuclear leukocytes (PMNs) play an important role in myocardial ischemia/reperfusion (MI/R) injury. Moreover, platelets are also important blood cells that can aggravate myocardial ischemic injury. This study was designed to test the effects of PMNs and platelets separately and together in provoking cardiac dysfunction in isolated perfused rat hearts following ischemia and reperfusion. Additional control rat hearts were perfused with $75{\times}10^6$ PMNs, with $75{\times}10^6$ platelets, or with $75{\times}10^6\;PMNs+75{\times}10^6$ platelets over a five minute perfusion followed by a 75 min observation period. No significant reduction in coronary flow (CF), left ventricular developed pressure (LVDP), or the first derivative of LVDP (dP/dt max) was observed at the end of the observation period in any non-ischemic group. Similarly, global ischemia (I) for 20 min followed by 45 minutes of reperfusion (R) produced no sustained effects on the final recovery of any of these parameters in any group of hearts perfused in the absence of blood cells. However, I/R hearts perfused with either PMNs or platelets alone exhibited decreases in these variables of $5{\sim}10%$ (p＜0.05 from control). Furthermore, I/R hearts perfused with both PMNs and platelets exhibited decreases of 50 to 60% in all measurements of cardiac function (p＜0.01). These dual cell perfused I/R hearts also exhibited marked increases in cardiac myeloperoxidase (MPO) activity indicating a significant PMN infiltration, and enhanced P-selectin expression on the coronary microvascular endothelium. All cardiaodynamic effects as well as PMN accumulation and P-selectin expression were markedly attenuated by a recombinant soluble PSGL-1 which inhibits selectin mediated cell adhesion. These results provide evidence that platelets and PMNs act synergistically in provoking post-reperfusion cardiac dysfunction, and that this may be largely due to cell to cell interactions mediated by P-selectin. These results also demonstrate that a recombinant soluble PSGL-1 reduces myocardial reperfusion injury by platelet and PMNs interaction.

• Journal of Chest Surgery
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• v.43 no.1
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• pp.104-107
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• 2010

Acute respiratory distress syndrome (ARDS) is difficult to treat and it is often fatal. If the medical treatment for ARDS is not effective, then extracorporeal membrane oxygenation (ECMO) can be applied to the patient. A 22-year-old female who suffered multiple traumatic injuries due to a car accident presented with acute respiratory distress syndrome. Veinarterial extracorporeal membrane oxygenation (VA ECMO) was started to treat her respiratory failure. With the VA ECMO, the systemic oxygen saturation remained at only 84%, and so the ECMO system was switched to V-VA ECMO via an additional venous outflow through the right jugular vein to increase both the systemic and pulmonary oxygen saturation. After conversion to the V-VA type ECMO, the systemic oxygen saturation increased to 94% and the partial pressure of oxygen ($PaO_2$) increased to 65 mmHg. We report here on a successful case of ECMO conversion from the VA type to the V-VA type in a patient with severely hypoxic respiratory failure.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.6
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• pp.583-590
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• 2013

Variable emittance radiators can be used in a thermal management system in space because their total emittance changes depending on the temperature of the system. When the temperature of the system decreased, the emittance also decreased so as to minimize the heat loss to the environment. In contrast, when the temperature of the system increased, the emittance also increased such that radiation cooling could occur. Thermochromic materials, whose emittance is a function of the temperature, are often used in variable emittance radiators because no additional parts are needed. In this study, we fabricated a variable-emittance coating by using a sol-gel method based on LSMO ($La_{1-x}Sr_xMnO_3$) and experimentally characterized the emittance change with respect to temperature. Furthermore, we also examined the stability of LSMO film in space environments by exposing it to extremely low pressure and temperature.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.137-144
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• 2005

Silica in primary system combines with an alkali grammatical particle metal and forms the zeolite layer which is hindering the heat transfer on the surface of the cladding. Zeolite layer becomes the cause of the damage in this way. The problems of the NPP's primary system have been issued steadily by EPRI. Through a series of experiments of the laboratory scale, we confirmed the applicability of NF membrane for silica removal, as silica rejection rate of NF membrane is about $60\;{\sim}\;70\%$ and boron rejection rate is about $10\;{\sim}\;20\%$. We accomplished a site experiment about four NF membranes manufactured by FilmTec and Osmonics Inc. In experiment using 400L of SFP water, when operation pressure is $10kg_{f}/cm^2$, we confirmed that the silica rejection rate of NF90-2540 manufactured by FilmTec Inc. is about $98\%$, boron rejection rate is about $43\%$. The silica rejection rate of NF270-2540 is about $38\%$, boron rejection rate is about $3.5\%$. Afterward, through additional experiments, such as long term characteristic experiments, we are going to design a optimum NF membrane system for silica removal.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.4
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• pp.273-283
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• 2020

Numerical simulations of the storm surge and waves induced by the Typhoon Bolaven incident on the west sea of Korea in 2012 are performed using the JMA-MSM weather field provided by the Japan Meteorological Agency, and the calculated surge heights are compared with the time history observed at harbours along the various coasts of Korea. For the waves occurring coincidentally with the storm surges the calculated significant wave heights are compared with the data measured using the wave buoys operated by the Korea Hydrographic and Oceanographic Agency and the Korea Meteorological Administration. Additional simulations are also performed based on the pressure and wind fields obtained using the best track information provided by the Joint Typhoon Warning Center, and the calculated results are compared and analyzed. The waves and storm surges calculated using JMA-MSM wether field agree well with the observations because of the better reflection of the topography and the pre-background weather field. On the other hand, the calculated results based on the weather fields produced using the JTWC best track information show some limitations of the general trend of the variations of wave and surge heights. Based on the results of this study it is found that the reliable weather fields are essential for the accurate simulation of storm surges and waves.