• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.399-406
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• 1996

Acidic fog is catastrophic to aviation and potentially affect materials, vegetation, crops and public health. This paper was carried out to investigate the chemical features of fog sample at Mt. Sobaek (mean sea level : 1, 340m) from June to August 1995. Each sample was analyzed for pH, electrical conductivity and major ions (anion : $Cl^N)_3^-, SO_4^{2-}, cation : Na^+, NH_4^+, K^+, Mg^{2+}, Ca^{2+}$) by ion chromatography. The quality analysis of fog sample data was performed based on ion balance and electrical conductivity method. The wind directions are subdivided into the northerly and southerly wind according to the wind direction data at the Sobaek-san meteorological observation station. Statistical analyses were performed on the complete set of results in order to obtain a description of fog sample. All the statistical treatment was carried out using the SPSS/PC + software package. The major ion concentration of fog samples was higher for the northwesterly wind cases than sourtheasterly wind cases. The pH of fog sample varied between 2.95 and 6.08. The average pH and electrical conductivity of total sample (n=210) were 4.39 and 113.0 $\mu$S/cm, respectively. It may be noted that in nearly all the cases, the dominant major ions in the fog sample at Mt. Sobaek were $SO_4^{2-}, NO_3^-, H^+ and NH_4^+$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.255-257
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• 2001

In this paper, the silicon rubber insulator for transmission line was experimented for 1,000 hours aging test in salt-fog condition. To evaluate and examine the aging properties of silicon rubber insulator for test, the leakage current of surface was measured. Also hydrophobicity and scanning electron microscopy were compared with initial and aged sample respectively Above results, we can confirm that the surface properties of silicon rubber insulator easily aged by salt-fog condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.255-257
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• 2001

In this paper, the silicon rubber insulator for transmission line was experimented for 1,000 hours aging test in salt-fog condition. To evaluate and examine the aging properties of silicon rubber insulator for test, the leakage current of surface was measured. Also hydrophobicity and scanning electron microscopy were compared with initial and aged sample respectively. Above results, we can confirm that the surface properties of silicon rubber insulator easily aged by salt-fog condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.25-28
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• 1998

In this study, we investigated the electrical characteristics of silicone rubber that being used outdoor insulating material, which had been immersed in salt water. After immersed the sample in salt water, we measured surface hydrophobicity, weight loss and microscopic surface appearance, and then compared with these of the original. And we tested the electrical characteristics of the aged sample by the water under salt-fog. These electrical characteristics are described by the average of leakage current, peak pulse number, which are recorded by data acquisition system The experimental results show that the resistance against tracking and erosion is decreased significantly by water penetration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.598-606
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• 2000

In this paper we investigated the relation between the surface degradations and anti-pollution characteristics of Room Temperature Vulcanized(RTV) silicone rubber coating that has different roughness through immersing into saline water. We utilized several analytic techniques such as atomic force microscopy(AFM) scaning electron microscopy(SEM) contact angle Salt Deposit Density(SDD) and average leakage current under the condition of salt fog. It is found that the surface roughness of treated RTV silicone rubber increased and the hydrophobicity of sample surface decreased with increasing the duration o immersion into water due to the erosion of base polymer the melting down alumina trihydrate(ATH) and the diffusion of Low Molecular weight(LMW) fluid. Despite the roughness of surface had been increased by water immersion excellant anti-pollution and recovery characteristics were maintained and SDD saturated to 0.1~0.14mg/cm$^2$. The average leakage current under salt fog increased with surface roughness. Measurement of average leakage current will be helpful to investigate surface degradation and lifetime expectation of RTV silicone coating.

• Asian Journal of Atmospheric Environment
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• v.11 no.1
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• pp.54-60
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• 2017

Quantifying the trace elements in infinitesimal ambient liquid samples (e.g., single raindrop, cloud/fog water, and the soluble fraction extracted from the particles collected for a short time) is an important task for understanding formation processes, heating/cooling rates, and their health hazards. The purpose of this study is to employ an in-air micro PIXE system for quantitative analysis of the trace elements in a thimbleful of reference liquid sample. The bag type liquid sample holder originally designed with $10{\mu}m$ thick $Mylar^{(R)}$ film retained the original shape without any film perforation and apparent peaks of film blank by the end of the analysis. As one of tasks to be solved, the homogeneity of the elemental distribution in liquid reference species was verified by the X-ray line profiles for several references. It was possible to resolve the significant peaks for whole target elements corresponding to the channel number of micro-PIXE spectrum. The calibration curves for the six target elements (Si, S, Cl, Fe, Ni, and Zn) in standard solutions were successfully plotted by concentration (ppm) and ROI of interest net counts/dose (nC).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.12 no.1
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• pp.1-10
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• 1999

In this paper, we have investigated the effects of the environmental factors on Low Molecular Weight (LMW) silicone fluid contents existing in high temperature vulcanized (HTV) silicone rubber sample, using dipping method and contact angle, current measurement. Artificial treatments such as immersion in water, elevated temperature, UV irradiation and dry band arcing under salt-fog condition are selected as the environmental factors. This results will be helpful to investigate the degradation with time and to expect a life time, because the LMW silicone content, which is important to recovery the hydrophobicity of silicone rubber surface, show different results by each environmental factors.

• Journal of Astronomy and Space Sciences
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• v.14 no.2
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• pp.330-346
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• 1997

Korea Multi-Purpose Satellite I (KOMPSAT-I, the first multi-purpose Korean satellite) will be launched in the third quarter of 1999, which is operated on the sun-synchronous orbit for cartography, ocean color monitoring, and space environment monitoring. The main mission of Electro-Optical Camera(EOC) which is one of KOMPSAT-I sensors is to provide images for the production of scale maps of Korea. EOC collects panchromatic imagery with the ground sample distance of 6.6m at nadir through visible spectral band of 510~730nm. For determining KOMPSAT-I crossing time over Korea, this study examines the diurnal variation of solar and atmospheric variables that can exert a great influence on the EOC imagery. The results are as follows: 1) After 10:30 a.m. at the winter solstice, solar zenith angle is less than $70^{\circ}$ and expected flux of EOC spectral band over land for clear sky is greater than about $2.4mW/cm^2$. 2) For daytime the distribution of cloud cover (clear sky) shows minimum (maximum) at about 11:00 a.m. Although the occurrence frequency of poor visibility by fog decreases from early morning toward noon, its effect on the distribution of clear sky is negligible. From the above examination it is concluded that determining KOMPSAT-I crossing time over Korea between 10:30 and 11:30 a.m. is adequate.

• Journal of Korean Academy of Nursing
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• v.5 no.1
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• pp.1-16
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• 1975

The newborn human is the only mammalian whose mother does not have a food supply ready for it's offspring at birth. From two to four days usually elapse before the mother's supply If milk appears, and during this period, some kind of artificial feeding should be supplied to the infants. Because of this factor, there has been continued debate fog the past hundreds of years as to when the first feeding should be started Accordingly, many experiments were carried out by scholars and because of these, Pre-lateral feedings were believed to be necessary. Many types of pre-lateral feedings were tried and the conclusion was reached that glucose water was the best food for the first infants'feedings. Traditionally, This has been started 12 hours after birth. The causes for the 12 hours delay were thought to (1) provide rest for the infants: (2) prevent regurgitation ana vomiting which tended to be prevalent during this tine: (3) in cases of low weight infants, prevention of aspiration pneumonia. From recent studies of newborn physiology and as pediatric medicine has been rapidly advancing, many studies hare been carried out concerning the improvement of infant nutrition and the early feeding of infants has been emphasized. This author believes it would be very beneficial to try two different kinds of feedings for the infant. (1) experimental feedings ana (2) comparative feeding, and during this period to investigate and compare the infants blood sugar level, hematocrit, gamma globulin level weight changes and to observe the infant reaction ill order to search for a more desirable feeding program. This study was conducted from January to March 1974 with data related to 40 healthy newborn infants (male 21, female 19: weight, 2.79∼4.20㎏ : gestation, 39∼40 weeks) born at Ewha Womens University Hospital and the results obtained were as follows : 1. At time of birth the blood sugar level from the cord sample averaged 88.99㎎/100㎖, but the blood sugar level rapidly dropped after 2 to 3 hours and reached the lowest point after 10 to 11 hours (54.48㎎/100㎖) and rose again by the 24 hour time period (76.80㎎/100㎖). Changes in the blood sugar level of the experiments: groups and the compare-five group was not significantly different until the 6 to 7 hour period, but by the 10 to 11 hour period the blood sugar levels of the experimental group (49,10㎎/100㎖) and the comparative group (49.70㎎/100㎖) were lower than the remainder of the experimental groups. 9. There ware no significant weight changes between the two groups. Average weight at birth was 3.35㎏, but at the 24 hours period birth weight averaged 3.29㎏. (1.8% reduction of birth weight). It continually lowered until at 48 hours, average weight was 3.26㎏ (2.7% reduction from birth weight.) 3. Hematocrit readings showed no significant difference between the groups. Hematocrit, the average value at birth, was 28.07% and abruptly elevated to average 64.35% at the 2 to 3 hour period, then slowly lowered to an average of 59.67% at the 6 to 7 hour period, 55.10% at the 10 to 11 hour period, ana 53.70% at the 24 hour period. 4. At birth, average gamma globulin value averaged 1,39㎎/100㎖. and at the 24 hour period averaged 1,52㎎/100㎖ revealing no significant difference between the two feeding groups. 5. Such factors as voiding, passing of meconium, regurgitation and vomiting showed no significance between the two feeding groups. However, the number of infants voiding and passing meconium in the experimental groups during the first 12 hours was slightly greater. In general there was an increased tendency for regurgitation and. vomiting among a small group of the infants during the first 24 hours which thereafter decreased. 6. Fluid intake averaged 24.38cc at the first feeding and increased to average 30.48cc at the third feeding and further increased to 73. 00cc at the fifteenth feeding. Finally it was suggested that the most reasonable method of early feeding is to give less than 25cc of 5% glucose water and/or 8% powdered milk at 8 to 9 flours after birth in order to prevent hypoglycemia and dehydration.