• 한국환경보건학회지
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• 제25권3호
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• pp.1-6
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• 1999

This study was conducted to survey trihalomethane(THMs) levels in finished water of J water treatment plant and examine its reduction by powder activated carbon(PAC) treatment. Samples were collected weekly based and head-space technique was employed to determine THMs levels by G.C-ECD. THMs levels in finished waters were highest in August and showed close relationship with water temperature. All the samples satisfied the drinking water limit(100 ${\mu}$g/l) for THMs. The individual formation rates of THMs were 64.8% for CHCl$_3$, 28.4% for CHCl$_2$BR, 6.5% for CHClBr$_2$ and 0.3% for CHBr$_3$, respectively and showed little monthly difference. The reduction efficiency of THMs formation by PAC treatment was 67% during July and August. Bromine substituents were more efficiently reduced than CHCl$_3$ by PAC.

• 한국결정성장학회지
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• 제9권6호
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• pp.558-562
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• 1999

승화 성장법을 적용하여 성장된 6H-SiC 결정에 대하여, KSV 이론과 성장 계면에서의 미사면(vicinal plane)상의 step 성장 양상을 근거로 하여, 성장 계면에서의 물질 흡착의 거동과 결함의 생성간의 상호 관계를 고찰하고, micropipes와 내부 결함의 생성 원인을 논하였다. micropipe와 면결함등의 결함들은 ledge 혹은 kink에 침입된 불순물에 의하여 step 성장의 진행이 방해받는 부분에 형성되었다. 따라서, SiC 결정에서 이들 결함의 생성은 SiC 결정 성장 계면에 형성되는 결정학적 step 성장면과 분자 또는 원자들의 격자 이동에 관련이 있음을 알 수 있었다.

• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.9-16
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• 2001

The purpose of this study is to investigate the functions of prefrontal lobe on the formation of conservation scheme of elementary students. In this study, 107 students of 4th to 6th grades were selected from the elementary school in Seoul area. As to the research,4 items for conservation logic test from GALT test sheet were used. The planning ability, inhibiting ability and reasoning ability were measured for the prefrontal lobe functions. About 30% of 4-6 grade students did not have volume conservation logic skills. The formation of conservations was not linear. Inhibiting ability was significantly different in level of conservation. And, conservation logic skills were significantly correlated with cognitive variables. Reasoning ability was significantly explained about 10% of the conservation logic in 4-6 grades.

• Applied Microscopy
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• 제21권2호
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• pp.14-28
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• 1991

The present study was designed in order to clarify ultrastructural characteristies of the spermatogenetic process and to examine survival state of the spermatozoa introduced into the female reproductive tract after autumnal coitus in the Korean greater horseshoe bats(Rhinolophus ferrumeguinum korai). The general morphological characteristics of spermatogenesis were principally similar to those of the other mammalian species; acrosomal formation, flagellar formation, middle piece formation and concentration of the spermatozoan nucleus. The spermatozoa introduced into the vagina were found to be dead forming a vaginal plug, the opaque central core of which consisted of trapped dead spermatozoa. Some spermatozoa introduced into the uterus were observed to be phagocytized by the polymorphonuclear leucocytes infiltrated into the uterine glandular lumen. The oviductal epithelium, consisted of ciliated and secretory cells; the luminal surface of secretory cells were covered by a number of microvilli with well developed glycocalyx, suggesting a close relationship to nutrient (e.g. glycogen) supply for the spermatozoa during hibernation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.332-335
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• 2006

Red tide(harmful algae) in the Korean Coastal Waters has a given a great damage to the fishery every year. However, the aim of our study understands the influence of meteorological factors (air and water temperature, precipitation, sunshine, solar radiation, winds) relating to the mechanism of red tide occurrence and monitors red tide by satellite remote sensing, and analyzes the potential area for red tide occurrence by GIS. The meteorological factors have directly influenced on red tide formation. Thus, We want to predict and apply to red tide formation from statistical analyses on the relationships between red tide formation and meteorological factors. In future, it should be realized the near real time monitoring for red tide by the development of remote sensing technique and the construction of integrated model by the red tide information management system (the data base of red tide - meteorological informations). Finally our purpose is support to the prediction information for the possible red tide occurrence by coastal meteorological information and contribute to reduce the red tide disaster by the prediction technique for red tide.

• Corrosion Science and Technology
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• 제10권1호
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• pp.37-42
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• 2011

Aluminum was electrochemically etched in acid solution and the surface area was magnified by the formation of etch pits. Etched aluminum was covered with a compact and dense dielectric oxide film by anodization and applied to the aluminum electrolytic capacitor electrode. Capacitance of aluminum electrolytic capacitor is closely related with surface area, which depends on size and number of etch pits. Size of etch pits need to be controlled because inside of the pits can be buried by the formation of dielectric oxide film. In this work, the effect of ultrasound pretreatment on the aluminum etch pit formation and capacitance were investigated. Additionally, the relationship between the second etching effect on pit size and capacitance was studied.

• 아태비즈니스연구
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• 제3권1호
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• pp.29-38
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• 2012

This study aims at evaluating the impact of network formation variables and found to have positive impact on the economic performance and growth of the enterprises. The calucation of the weighted scores of networking statements brought some affirmative results to influence the performance of the enterprises. Through multiple regression and logistic regression models it is identified that network formation variables like service receiving status, consultation of the family, other business dummy and attendance in fair have some significant positive impact both on the growth and performance of the enterprises. In addition to above variables, from the set of enterprise characteristics natural logarithm of the market value of total assets and from the entrepreneurs' characteristics set of variables, schooling year and squared value of the experience have been found to have significant positive impact. Finally, it is concluded in the study that to enhance the performance and growth of the enterprises, government and policy rlated organizations need to consider important variables that have positive impact in supplying the entrepreneurial resources especially, developing the net-working relationship.

• 한국표면공학회지
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• 제29권6호
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• pp.648-653
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• 1996

Hydrogenated amorphous carbon(a-C:H) films are prepared by rf plasma CVD in a $CH_4$ source gas system diluted with Ar of $H_2$. The spectra of emissive and reactive species in the plasma are detected using in stiu optical emission spectroscopy. Inaddition, the relationship between the film properties which can be varied by the deposition parameters and the Raman spectra is studied. In the $CH_4/H_2$ gas system, the emission intensities of CH and $H \tau$ decrease and those of $H \alpha$, $H \beta$, $C_2$ and Ar increase with increasing $H_2$ concentration, The formation of $C_2$ and CH in the $CH_4/Ar/H_2$ gas system is greatly suppressed by hydrogen addition and the excess of hydrogen addition is found to form graphite structure. The $C_2$ formation in the gas phase enhances a-C:H film formation.

• 한국분무공학회지
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• 제8권2호
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• pp.24-30
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• 2003

An experimental study was performed to investigate the influence factors of drop formation in electrohydrodynamic atomization. The mode of electrohydrodynamic atomization depended on the various factors such as the flow rate of the liquid, the inner diameter of the nozzle, the distance between the nozzle tip and the ground electrode, the shape of the ground electrode. and the applied high voltage. This work was performed to investigate the experimental analysis for the flow pattern visualization of droplets, and the relationship between voltage application and the behavior of liquid atomization. Uniform drops of different sizes can be obtained at the inception of the spindle mode by charging the flow rate and the electric field. The drop size also decreased when the flow rate was raised for the spindle mode. The whipping motion occurred beyond 7kV and before the corona started to take effect.

• Mycobiology
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• 제38권2호
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• pp.118-121
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• 2010

Single ascospore isolates of Cordyceps bassiana were observed for their colony pigmentation on Sabouraud Dextrose agar plus Yeast Extract (SDAY) plates and were inoculated in a brown rice medium for production of fruiting bodies. Colony pigmentation did not show any relationship with perithecial stromata formation. The isolates were also grown on opposite sides of SDAY agar plates and were observed for vegetative compatibility. Neither vegetative compatibility nor perithecial stromata could be found to be related to each other. It was concluded that fertile fruiting body production was independent of colony pigmentation and vegetative compatibility. Synnemata formation was found to be more common than perithecial stromata formation. This might be due to its highly conidiogenous anamorphic stage, i.e., Beauveria bassiana.