• Membrane Journal
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• v.24 no.3
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• pp.201-212
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• 2014

This study was performed to discover the optimum operation conditions for the advanced water treatment using the ceramic membrane, introduced the first in the nation at the Y water treatment plant (WTP). The result of investigation to find the optimum operation conditions which can continue preserving the filtration performance as well as satisfying both the economics and the water quality is as follows. In the ordinary water quality condition of the Y WTP, the optimum filtration time(the backwash period), which can minimize the production of backwash waste and preserve the membrane performance was examined to be 4.0 hours on basis of institution capacity ($16,000m^3/day$). Examining the recovery rate of TMP from the chemical cleaning (CIP) discovered that the inorganic contaminants, which cause membrane fouling, such as iron, manganese, aluminum, were removed through the acidic cleaning using citric acid, whereas the membrane recovery rate was found to be low. But, on the other hand, the TMP was recovered to the initial value from the alkali cleaning using the NaOCl. Therefore, the main contaminant causing the fouling was determined to be hydrophilic organic compound( biopolymer). The membrane recovery rate is highly influenced by the temperature of the cleaning chemical. That is, the rate increased with increasing temperature.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.65-72
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• 2007

The VOC (volatile organic compound) analyzer is devised to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styfene. It is not affected by ambient temperature and humidity. In addition, standby and measuring time of VOC Analyzer is a short as below 30 min and 8 min, respectively. Since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. In this study, VOC emission behavior from 4 types paints (lacquer, urethane vanish, water-base paint, enamel paint) for wood-based panel was investigated using VOC Analyzer. After a specimen was spreaded on aluminum foil ($6.32{\times}6.32cm$) in $3{\ell}$ polyester bag, after 24 hours we could measure maximum VOC emission level that is a stabilized VOC value. Xylene of VOCs was high emitted from lacquer, urethane vanish and water-based paint, and TVOC (Toluene + Ethylbenzene + Xylene + Styrene) of lacquer was the highest emission concentration than another.

• Journal of radiological science and technology
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• v.20 no.2
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• pp.49-55
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• 1997

This study was carried out to investigate radiographical and operating conditions of X-ray units and exposure doses to patients during chest radiography, so that the results could provide basic data used for reducing the exposure dose and for providing the diagnostic information with better quality. The conditions and exposure doses of 100 X-ray units mainly used for chest radiography were examined and also 100 radiological technologists mainly handling those apparatus at 76 medical facilities in Pusan were surveyed using a questionnaire from October 1 to December 31 in 1995. The following results were obtained from the study : 1. It was found that most units were capable of taking a high tube voltage radiography by showing 67% of the units equipped with the maximum tube voltage of 150 kV, 94% with more than 500 mA for the rating capacity and 85% with the full wave type of a signal phase. 2. For actual chest radiographical conditions, however, 80% of the units were operated at $60{\sim}100\;kVp$ and only 14% at 100 kVp and over for the high tube voltage. 3. The average exposure time was less than 0.1 second, and eighty four percent of the units adapted the X-ray tube currents ranging from 200 to 300 mA, 80% the focus-film distances between 180 and 210 cm, and 63% the focus sizes of more than 2.0 mm. 4. Most units(98%) employed additional filters made of aluminum, 75% the thickness of filters less than 2.0 mm, and only 2 units the compound filters. 5. Ortho chromatic system was only adopted in 13% of screen film system for the units, and 73% used the grid ratio at 8 : 1 for the low tube voltage during chest radiography. 6. The average exposure dose of all X-ray units during chest radiography was $371\;{\mu}Sv$ with a difference of about 16 times between the minimum to the maximum, and $386\;{\mu}Sv$ both at hospitals and at health centers, followed by $380\;{\mu}Sv$ at general hospitals and $263\;{\mu}Sv$ at university hospitals without showing any statistically significant differences. In conclusion, since patients during chest radiography at medical facilities in Pusan exposed to high levels of radiation, it is recommended that appropriate added filters and grids necessary for the high tube voltage radiography and high-speed screen systems should be adopted and used as soon as possible in order to reduce exposure dose to the patients.

• Journal of Nutrition and Health
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• v.5 no.2
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• pp.91-103
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• 1972

Zinc is one of the essential trace elements in the living organism for growth and health. The first identified metalloenzyme, carbonic anhydrase, is a zinc compound and several others have been described since. Among zinc deficiency syndromes in animals porcine parakeratosis has been successfully treated with zinc supplements, and in man a syndrome of anemia, hypogonadism, hepatosplenomegaly, and dwarfism, prevalent in parts of Iran and Egypt, has been ascribed to lack of zinc in the diet. Dietary zinc excess in the rat is manifested by a hypochromic, microcytic anemia, poor growth, reduction in liver catalase and cytochrome oxidase. The present study is an attempt to delineate the changes of tissue contents of trace elements, especially of iron, copper and zinc in liver and kidneys of the rats. Weanling albino rats, weighing 60 to 80gm. were used in this experiments. The rats were housed in cages with aluminum floors and received feed and distilled water ad libitum. Animals were divided into three groups, control, low zinc diet and high zinc diet groups. The high zinc diet group was subdivided into 0.5% Zn and 0.7%Zn groups. The supplementary copper or iron was added to the high dietary zinc groups. The animals were sacrificed and the tissues were washed several times with deionized water. The wet digested samples were analyzed by Hitachi Model 207 atomic absorption spectro-photometer for the determination of iron, copper and zinc in the liver and kidney. Hemoglobin level in the blood was measured by cyanmethemoglobin method. The results of this study are as follows: 1) All rats fed high zinc diets and low zinc diets gained less weight than control. Weight gain was not improved by the supplementary copper or iron and both. 2) Hemoglobin concentration was decreased significantly in the rats fed high zinc diets and less in the low zinc diet. Supplementary copper and iron to the higher zinc diet appeared to give some improvement of anemia. 3) The iron contents of the liver and kidneys were significantly decreased in the high zinc groups and the reduction was more significantly in the rats receiving higher zinc diet (0.7%). The supplementary copper caused a further depression of liver iron. On the other hand, the iron, added to the high zinc diet lessoned the severity of the decrease in liver iron and caused kidney iron to be maintained almost at the level found in the rats fed by zinc and supplementary copper diet. 4) High zinc diets did not change copper content of the liver and kidney. Supplementary copper elevated the concentration in the liver and kidney and added iron had no effect on the accumulation of copper in the liver and kidneys. 5) The high zinc diets caused marked increases of zinc content in the liver and kidney. Supplementary iron to the high zinc diet caused increases of zinc contents of liver and kidneys.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.408-416
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• 2020

This study examined the neuronal cytotoxicity of aluminum chloride (AlCl3), a dementia inducer, and the protective effects of Aster yomena (Kitam.)(AY) extract on AlCl3-induced cytotoxicity in cultured C6 glioma cells. The antioxidative effects, such as the inhibitory ability of xanthine oxidase (XO) and superoxide anion-radical (SAR) scavenging ability, on cell viability were examined. AlCl3 decreased the cell viability significantly in a dose-dependent manner, and the XTT50 value was 130.0 μM in these cultures. The cytotoxicity of AlCl3 was determined to be mid-toxic according to the Borenfreund and Puerner' toxic criteria. Quercetin (QU), an antioxidant, increased the cell viability reduced by AlCl3-induced cytotoxicity. The protective effect of the AY extract on AlCl3-induced cytotoxicity was analyzed. The AY extract increased the cell viability remarkably compared to the AlCl3-treated group and showed the inhibitory ability of XO and SAR-scavenging ability. The cytotoxicity of AlCl3 was correlated with oxidative stress, and the AY extract effectively prevented AlCl3-induced cytotoxicity through its antioxidative effects. In conclusion, natural resources, such as the AY extract, may be a putative agent for improving the cytotoxicity of heavy metallic compounds correlated with oxidative stress, such as AlCl3, a morbid agent.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.3
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• pp.211-218
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• 2018

Instant face lifting cosmetics contain various film forming agents for stretching the wrinkles on the skin surface. But, most of the film-forming polymers have sticky feels. And they are easily scrubbed out when skin is rubbed on. In this study, we focused on the influence of sodium silicate that has rapid film forming effect on skin surface and immediate wrinkle reducing effect. Sodium silicate, also known as water glass or soluble glass, is a compound containing sodium oxide and silica. Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. Sodium silicate is stable in neutral and alkaline solutions. The sodium silicate solution hardens by drying in air and rapidly forms a thin film. When the solution is applied to the skin, the fine membrane coating is formed by water evaporation and ionic bond re-formation. It also makes the strong siloxane (Si-O) bonding on the skin surface. When these fixation properties are applied to cosmetics, they can give remarkable skin tightening effect. The sodium silicate solution can provide the lifting effect by forming a film on skin at a proper concentration. But, skin irritation may be caused with too high concentration of sodium silicate. We studied a desirable range of the sodium silicate concentration and combination with other fixatives for skin care formulation that has no sticky feels and no scrubbing out phenomenon. Immediate lifting gel was developed by using sodium silicate and various thickening systems. Among of the various thickeners, aluminum magnesium silicate showed the best compatibility with sodium silicate for rapid lifting effect. This instant physical lifting gel was confirmed as a low stimulating formula by skin clinical test.

• Food Science and Preservation
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• v.14 no.4
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• pp.414-418
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• 2007

The physicochemical characteristics and sensory properties of Deodeok wine, formed by leaching of Deodeok at room temperature for 180 days, were investigated over the following range of Deodeok levels: 10, 15 and 20% (all w/v). The higher the level of Deodeok, the greater were the final values of total sugars, reducing sugars, total polyphenols, and crude saponins. The Hunter's b-value (yellowness) of Deodeok wine varied markedly with Deodeok levels, and yellowness was highest in Deodeok wine containing 20% (w/v) Deodeok. Non-volatile compounds, that form the basis of the liquor tax law, were 0.64, 1.38 and 2.11% (all w/v), respectively, at day 160. Of these values, that of 2.11% (w/v), the level of non-volatile compounds in Deodeok wine containing 20% (w/v) Deodeok, was in accord with the liquor tax law (that requires this figure to be 2.0%). Sensory evaluation showed that Deodeok wine containing 20% (w/v) Deodeok was superior to the other wines tested.

• Conservation Science in Museum
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• v.29
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• pp.133-152
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• 2023

This study references preceding studies to examine the history of paint application techniques using various paints in the past, with the aim to contribute to the long-term preservation of large military cultural heritage assets situated outdoors. To this end, the study compared the findings of preceding research with the findings of an analysis conducted on a H-13 helicopter housed at the War Memorial of Korea. Upon collecting and analyzing samples from three grounded WWII aircraft from above-ground by preceding studies, it was confirmed from each sample that the various chemical properties of chrome ensured the effectiveness of the protective coating. The compound was first tested as a corrosion-inhibiting pigment in the early 1940s and proved its excellent moisture-resistant properties over the course of 80 years, despite the deterioration of the paint layer and long-term exposure to the natural environment. For this reason, it has been widely used as a corrosion inhibitor for aluminum alloys in the aviation industry. In other word, the most widely-used material for preventing corrosion was an organic primer containing chromate. In this study, based on the paint analysis of a H-13 helicopter operated in the Korean War, it was shown that the second layer, consisting of the primer, contains chromium oxide (Cr₂O₃). In addition, it was estimated that red lead tetraoxide (Pb₃O₄) was used for the vehicle. Analysis results and data from previous studies can help to confirm the continued effectiveness of corrosion prevention function provided by chromate. Meanwhile, the result of infrared spectroscopy analysis confirmed the use of alkyd resin. In the future, comparisons with a more diverse range of artifacts will allow the identification of changes in the manufacturing technology of paints used to protect alloys from corrosion.