• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.395-398
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• 2000

Reactive radio frequency (RF)magnetron sputter with incident angle has been used to deposit AlN thin film on a crystalline Si substrate. (002)Preferred orientation of AlN thin film has been obtained at low sputtering pressure. Also it has been shown that depostion rate of AIN thin film is affected by fraction Ar and $N_2$ partial pressure. But substrate temperature didn't affect depostion rate of AIN thin film . As sputtering pressure increased preferred orientation degraded. The internal stress changed from tensile stress to compressive stress as fraction of $N_2$ partial pressure increased. At low nitrogen partial pressure cermet$^{[1]}$ AIN thin film is obtained.

• Korean Membrane Journal
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• v.3 no.1
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• pp.39-50
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• 2001

The counter-diffusion of two gaseous substances permeating a polymeric membrane has been investigated both experimentally and theoretically. The aim of the study was to find mutual effects, if any, that could influence the permeability and diffusivity data. The experimental data were obtained with an isostatic permeameter operating at ambient pressure and 303 K: helium, nitrogen, carbon dioxide methane were used as permeating gas at different partial pressure; helium or nitrogen as equilibrating or carrier gas. No evident mutual effect of the counter-diffusing gas was observed. The theoretical analysis gave some insight into the phenomena and it was concluded that at near-atmospheric pressures, and in the absence of swelling phenomena no mutual interaction exists. On a theoretical basis any mutual interaction between diffusing and counter-diffusing gases could only occur: i) at high pressures , when the free movement of permeating gas molecules within the polymer is hindered by the counter-diffusing gas; ii) when a large part of the free volume fraction is occupied by the counter--diffusing gas; iii) swelling phenomena modify the structure and free volume fraction of the polymer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.679-688
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• 1994

Physicochemical and morphological characteristics of biopellets produced in "control" and modified UASB reactor were investigated to compare the reactor performance with regard to the hydrogen partial pressure. The characteristics of biopellet produced in modified UASB reactor operated with high hydrogen partial pressure were better than those of "control" reactor operated with relatively lower hydrogen partial pressure, therefore the hydrogen partial pressure effected greatly on the formation and stability of the biopellet. Furthermore, pellets from the UASB system with modified settler showed a better settleability and biomass holding capacity. The chemical composition of biopellet was distinctively different from that of common bacterial formula, $C_5H_7O_2N$. Biopellets was composed the large fraction of nitrogen in comparison with common anaerobic microbes. These results implicated the existence possibility of polypeptide-type extracellular polymer. The morphological characterization with SEM showed that microorganisms observed at surface of biopellet produced in modified UASB reactor operated with high $P_{H_2}$ condition were very similar in shape and size to the Methanobrevibactor arboriphilus-$H_2$ utilizing methanogen. The microorganisms was distinguished from those of "control" reactor operated with low $P_{H_2}$ condition. From these results, it could be explained the hydrogen partial pressure effects on pelletization mechanism.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.288-292
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• 2003

AlM thin film has been deposited on A1$_2$O$_3$ substrate by reactive radio frequency(RF) magnetron sputtering method under various operating conditions such as working pressure, fraction of nitrogen partial pressure, and substrate temperature. Scanning Electron Microscope(SEM), X-ray Diffraction(XRD), and Atomic Force Microscope(AFM) have been measured to find out structural properties and preferred orientation of AlN thin films. SAW velocity of IDTs/AlN/Si structure was about 5038［㎧］ at the center frequency of 251.9［MHz］ and insertion loss was measured to be relatively low value of 35.6［dB］. SAW velocity of IDTs/AlN/A1$_2$O$_3$ structure was improved to be about 5960［㎧］ at the center frequency of 296.7［MHz］.

• Journal of Trauma and Injury
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• v.32 no.3
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• pp.136-142
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• 2019

Purpose: Near drowning refers to immediate survival after asphyxia due to submersion or immersion in water, which is a crucial public safety problem worldwide. Acute lung injury or acute respiratory distress syndrome (ARDS) is a common complication of near drowning. The purpose of this study was to investigate the feasibility and effectiveness of noninvasive nasal positive pressure ventilation (NINPPV). Methods: This retrospective study was conducted at a tertiary emergency department. NINPPV was administered for moderate ARDS caused by submersion or immersion in patients who were older than 18 years, from January 2015 to December 2018. We collected the demographic (age, sex, length of hospital stay, and outcome), laboratory (arterial blood gas, lactate, oxygen saturation, partial pressure of oxygen divided by the fraction of inspired oxygen, complete blood count, blood urea nitrogen, and creatinine), and clinical data (acute lung injury index and ventilator failure) of the patients. A statistical analysis was performed using Statistical Package for the Social Sciences version 20.0 for Windows. Results: NINPPV treatment was provided to 57 patients for near drowning, 45 of whom (78.9%) were successfully treated without complications; in 12 (21.1%), treatment was changed to invasive mechanical ventilation within 48 hours due to ARDS or acute kidney injury. NINPPV treatment was successful in 31 (75.6%) out of 41 sea-water near drowning patients. They were more difficult to treat with NINPPV compared with the fresh-water near drowning patients (p<0.05). Conclusions: NINPPV would be useful and feasible as the initial treatment of moderate ARDS caused by near drowning.