• Korean Journal of Food Science and Technology
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• v.17 no.3
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• pp.203-207
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• 1985

Relationship between cell surface hydrophobicity and pellicle formation was studied in a film strain isolated from stored apple wine and identified as Hansenula beijerinckii FY-5. In the media containing non-ionic surface-active agents the pellicle formation of strain FY-5 was efficiently repressed, whereas growth of the yeast was possible, and also cell surface hydrophobicity was greatly decreased by the addition of these agents. These results indicate that a pellicle formation factor, which keeps yeast cells floating on the medium surface, is necessary for the pellicle formation, and surely this factor is the hydrophobicity of the cell surface. The pellicle formation in the film strains was abundant with the increase of the cell surface hydrophobicity, whereas the non-film strains had less hydrophobicity as compared with the film strains. Ethanol, as a sole carbon source, efficiently increased hydrophobicity more than glucose, and the hydrophobicity was lowered with the rise of pH. In the experiments of time course, the hydrophobicity was increased in proportion to cell growth, and was maximum during the stationary phase.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.328-335
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• 2010

We have designed and fabricated an active pixel sensor(APS) using an optimized n-well/gate-tied p-channel metal oxide semiconductor field effect transistor(PMOSFET)-type photodetector with a built-in transfer gate. This photodetector has a floating gate connected to n-well and a built-in transfer gate. The photodetector has been optimized by changing the length of the transfer gate. The APS has been fabricated using a 0.35 ${\mu}m$ standard complementary metal oxide semiconductor(CMOS) process. It was confirmed that the proposed APS has a wider dynamic range than the APS using the previously proposed photodetector and a higher sensitivity than the conventional APS using a p-n junction photodiode.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.2
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• pp.115-124
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• 2024

Objectives: The aim of this study is to assess indoor air quality within and around buildings and evaluate the health risks associated with exposure to indoor air pollution. The study compares IAQ standards established by the World Health Organization with those set by South Korea's Ministry of Environment and Ministry of Education. Methods: The study utilized an Anderson Sampler and DustTrak^TM II to collect samples of total airborne bacteria and PM in indoor and outdoor environments. Collected samples were analyzed using biological and biochemical methods. Statistical analysis was conducted using SPSS to examine the correlation between airborne bacteria and PM. Results: The study revealed that the concentration of total airborne bacteria in indoor air generally remained below the Ministry of Environment's standard of 800 CFU/m³, although it surpassed this threshold in certain instances. PM concentrations did not exceed the standards. Indoor fine dust concentration was higher when there were people (P<0.05). There was no difference in total floating bacterial concentrations between indoor and outdoor environments (P=0.184). Finally, there was a correlation between fine dust and airborne bacteria concentrations. Conclusion: The study evaluated the concentrations of total airborne bacteria and PM in indoor air, emphasizing the importance of managing IAQ. Further research in various environments is essential to ensure a healthy indoor environment. The findings underscore the need for ongoing research and management to enhance IAQ and create safer and healthier living environments.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.491-500
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• 2022

It has been noted that an accurate estimation of wind loads on offshore structures such as an FLNG (Liquefied Natural Gas Floating P roduction Storage Offloading Units, LNG FPSOs) with a large topside plays an important role in the safety design of hull and mooring system. Therefore, the present study aims to develop a computational model for estimating the wind load acting on an FLNG. In particular, it is the sequel to the previous research by the author. The numerical computation model in the present study was modified based on the previous research. Numerical analysis for estimating wind loads was performed in two conditions for an interval of wind direction (α), 15° over the range of 0° to 360°. One condition is uniform wind speed and the other is the NPD model reflecting the wind speed profile. At first, the effect of sand-grain roughness on the speed profile of the NPD model was studied. Based on the developed NPD model, mesh convergence tests were carried out for 3 wind headings, i.e. head, quartering, and beam. Finally, wind loads on 6-degrees of freedom were numerically estimated and compared by two boundary conditions, uniform speed, and the NPD model. In the present study, a commercial RANS-based viscous solver, STAR-CCM+ (ver. 17.02) was adopted. In summary, wind loads in surge and yaw from the wind speed profile boundary condition were increased by 20.35% and 34.27% at most. Particularly, the interval mean of sway (45° < α <135°, 225° < α < 315°) and roll (60° < α < 135°, 225° < α < 270°) increased by 15.60% and 10.89% against the uniform wind speed (10m/s) boundary condition.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.694-706
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• 2012

The purpose of this study was to offer the raw data for conservation and restoration of aquatic ecosystem by surveying and analysing a water quality, sediment, benthic macroinvertebrate, fish and hydrophyte in Junam reservoir. In the result of analysing the water quality, pH was 8.2~8.4, 6.0~7.5mg/${\ell}$ in COD, 10.0~10.3mg/${\ell}$ in SS, 8.3~11.5mg/${\ell}$ in DO, 0.1mg/${\ell}$ in T-P and 1.2~1.3mg/${\ell}$ in T-N. In case of the sediments, Cd was 0.47~0.52mg/kg, 7.08~7.43mg/kg in Cu, 0.22~0.32mg/kg in As, 0.02~0.03mg/kg in Hg, 6.20~7.45mg/kg in Pb, 32.80~39.70mg/kg in Ni, 513.0~543.0mg/kg in F and 137.0~140.0mg/kg in Zn. $Cr^{6+}$ was not detected. The benthic macroinvertebrates were 432 individuals including 3 phyla, 5 classes, 9 orders, 26 families, 33 genera and 39 species, and the ecological score of benthic macroinvertebrate community(ESB) was 25. The fishes were 8 families and 14 species, and the invasive alien species were 2 taxa including Micropterus salmoids and Lepomis macrochirus. The hydrophytes were 63 taxa including 28 families, 42 genera, 56 species, 1 subspecies and 6 varieties. The emergent plants were 38 taxa(60.3%), 5 taxa(7.9%) in floating-leaved plants and each 10 taxa(15.9%) in free-floating plants and submerged plants.

• Journal of Chest Surgery
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• v.29 no.7
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• pp.689-699
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• 1996

An animal experiment was designed for the evaluation of in vivo performance of the newly developed electrohydraulic type ventricular assist device and its influence on the left ventricular function during pal- satile left ventricular assist. Eight adult sheep were incorporated into the study and data were collected from seven sheep. Total as- sist time ranged from 69 minutes to 7 days. The performance of the device was satisfactory both in asyn- chr nous and synchronous mode within the range of given native heart rate. More than 4 liters of device output could be reached within the range of normal left atral pressure without development of negative pressure in the left atrium. Moderate to severe degree of hemolysis was noted as evidenced by significant increase of plasma free hemoglobin level after 3 days of left ventricular support along with the presence of the small amount of thrombi around the floating disc type polymer valve apparatus reflecting that further study and refinement of the device need to be done in regard of biocompatibility and thromboresistance. The hemodynamics showed increase in heart rate (p < 0.05), cardiac output and left ventricular minute work (p < 0.05) after placement of the device at the flow rate of 2.0∼2.5 Llmin. The left atrial pressure, left ventricular pressure and LV dpldt were decreased after the device placement(p < 0.05). The endocardial viability ratio and oxygen contents of the mixed ven us blood and coronary venous blood were all increased (p < 0.05) after the device placement suggesting effective unloading of the left ventricle was accomplished. The myocardial perfusion was thought improved in synchronous counterpulsation as suggested by sig- nificant increase in endocardial viability ratio and coronary venous blood oxygen content in synchronous assist mode comparing with asynchronous mode.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.258-264
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• 2014

This study is to investigate water quality changes of nitrogen (N) and phosphorous (P) at Gangjung-Goryeong Weir and Dalseong weir, in 2012-2013. Concentration of COD, TOC, T-N, T-P showed 3.5~6.8 mg/L, 3.4~6.5 mg/L, 1.8~4.0 mg/L, 0.08~0.12 mg/L respectively, in the Nakdong river main stream. Water quality of Dalseong weir showed lower level of contamination than that of Gangjung-Goryeong weir. Because of input loading of nutrients and organic matters from tributaries. At the analysis of sediments at each weirs, sedimentation fluxes of the hypolimnion represented 1.6~2.4 times higher than epilimnion fluxes. Sinking rate (%/d) of SS, N and P of the hypolimion showed in the range of 1.68 %/d~2.42 %/d. It is implied that the suspended matters seem to be floating in the water body. In the result of nutrients release experiment, release flux of nutrients in July showed 3~4 times higher than April. The reason was considered that nutrients is easily released in the anaerobic condition and at high water temperature.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.141-148
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• 2010

Feasibility of floating aquatic plants (Eichhornia crassipes and Water dropwort) was investigated in order to control of sewage depending on various initial loading in a lab scale test. In addition, field test was conducted to assess the uptake rate of nutrient by E. crassipes. Lab-scale test applying primary domestic effluent operated at 4 day HRT shows that the highest uptake rates were 1.06 g N/$m^2{\cdot}day$ and 0.39 g P/$m^2{\cdot}day$ in the E. crassipes reactor. BOD removal efficiency in E. crassipes reactor was as high as 80% when the loading value was lower than 185 kg BOD/$ha{\cdot}day$. While 70 ~ 80% removal efficiency of BOD was achieved when the loading value was lower 80 kg BOD/$ha{\cdot}day$ at the W. Dropwort reactor. Experiment results show that E.crassipes has a higher nutrients removal efficiency than W. dropwort under high pollutant loading. Input loadings of TN and TP should not exceed to 10 kg TN/$ha{\cdot}day$ and 2.0 kg TP/$ha{\cdot}day$ respectively to provide a 50% TN and 80% TP removal efficiencies using E. crassipes. The field test demonstrated that an annual yield of E. crassipes mass was estimated as a fresh weight of 30.9 $m^3/ha{\cdot}yr$. E. crassipes grown in field pads absorbed 76.7 kg N/$ha{\cdot}yr$ and 13.4 kg P/$ha{\cdot}yr$ as a dry weight.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.113-123
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• 1995

This study was intended to identify the neurotic traits related to sexual abuse in female high school students. The Neurosis Scale of Middlesex Hospital Questionnaire was conducted to 320 female high school students in Taegu, Korea from July 10 to July 17, 1994. The results were as follows: 1) The sexual abuse victim group showed significantly higher neurotic traits of Free floating anxiety (p<0.05), Phobic(p<0.01), Obsession(p<0.01), Somatic(p<0.05), Depression(p<0.01) than the control group. 2) The Neurotic traits of Somatic(p<0.01), Depression(p<0.01), Hysteric(p<0.01) were higher in the multiple-abused than the single-abused. 3) When the duration of being abused was concerned, subjects with more than 1 year duration had significantly higher neurotic traits of Obsession(p<0.05), Somatic(p<0.05), Depression(p<0.05) than subjects with less than 1 year duration. 4) The neurotic traits of Phobic, Somatic, Depression were significantly higher in the subjects with higher intensity of sexual abuse than with lower intensity. S) Among 68 victims, 31 girls(45%) were assaulted by strangers, 10(14%) were by relatives, 7(10.3%) were by siblings, 6(8.8%) were by neihbors. Among them, 34 girls(50%) bad counselling or psychotherapy and the people to whom they had sought for help were friends(23 girls; 68%), parents (7 girls; 11.7%) and mental health professonals (2 girls; 5.9%).

• Resources Recycling
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• v.27 no.1
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• pp.45-54
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• 2018

This study aimed to investigate the effects of mechanical factors such as agitation speed and air rate in fly ash flotation. Specifically, we used thermal power plant fly ash with unburned carbon content of 3.4 to 3.7%. The effect of pH, agitation speed, collector dosage, and frother dosage - the key factors of froth flotation - showed unburned carbon recovery and unburned carbon content of 63% and 34%, respectively, when the dosage of safflower oil used as collector was 800 g/ton, pH was 7, agitation speed was 1,200 rpm, and frother dosage was 400 g/ton. The SEM/EDS analysis of fly ash in that case indicated that the spherical fly ash particles lowered the unburned carbon content as they floated with the air bubbles without being dissolved in the unburned carbon or settled in the ore solution. The other experiment of changing the mechanical factors such as agitation speed and air rate resulted in unburned carbon recovery and unburned carbon content of 74% and 67%, respectively, at air rate of 8 L/min and agitation speed of 900 rpm. The recovery and unburned carbon content increased as the low agitation speed and additional air injection decreased the strength of the eddy current in the ore solution and consequently prevented the floating of fine fly ash particles with unburned carbon. In addition, the recovery rate and unburned carbon increased further to 80% and 70%, respectively, showing the best performance when the agitation speed and air rate were lowered to 800 rpm and 6 L/min, respectively.