• 청정기술
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• 제2권1호
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• pp.22-31
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• 1996

• 한국환경보건학회지
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• 제31권5호
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• pp.411-414
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• 2005

Clean Natural is a new disinfectant of which main components are propolis and wood vinegar from Quercus mongolica. The mutagenicity of Clean Natural was studied by a micronucleus test in male ICR mice. The maximally tolerated dose (MTI) of Clean Natural was determined to >2.0 g/kg body weight. Therefore, the doses adopted for the micronucleus test was 2.0 g/kg as a high dose, 1.0 g/kg as a medium and 0.5 g/kg as a low of dose, respectively. Each of group was consisted of three doses of Clean Natural, positive control 2 mg/kg of mitomycin C and negative control 20 ml/kg of saline. A slide preparation was made at 24 hours following administration. No significant induction of micronuclei was observed in any of the three doses of Clean Natural orally administered. No cytotoxicity such as inhibition of hemopoiesis was observed in any group of test agent as the rate of polychromatic erythrocytes to total erythrocytes was over 40%. These results indicate that Clean Natural is not capable of inducing micronuclei in vivo mouse cells and thus has no genotoxicity in micronucleus test.

• 환경위생공학
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• 제10권3호
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• pp.131-138
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• 1995

As the energy consumption increases continuously, the emission amount of air pollutants is growing, and after all it can influence the global environment as welt as the regional atmosphere. So, the clean energy which emits less air pollutants should be developed and widely used to reduce emission of pollutants. Electricity, known for clean energy in the side of consumption, is not actually clean in the process of generation. Electric power is generated using fossil fuels which produce acidic gases like $SO_{2}$, $NO_{x}$, etc. The emission rates of $SO_{2}$, $NO_{x}$, $CO_{2}$ are 2g,0.78g and 1 l0g per electric power generating Ikwh. If one light(60 watt bulb) be turned off at each house for a month electricity will be saved about 1.Skillion kwh a year. This is almost the same as 4,170 tons of $SO_{2}$ and $NO_{x}$. As a result the economization of electricity will be one of the effective strategy to reduce the air pollution and to keep our life clean and comfortable.

• Toxicological Research
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• 제21권3호
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• pp.263-269
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• 2005

This study was performed to investigate repeated-dose toxicities of Clean natural, a new disinfectant, in Sprague-Dawley(SD) rats. In the 4-week repeated oral toxicity study, Clean Natural was orally administered once daily via gavage to male and female rats at dose levels of 0, 500, 1,000 and 2,000 mg/kg body weight for 4-weeks. There were no deaths and clinical signs during the dosing period. In both sexes, there were no statistically significant differences between the administered and control groups in urinalysis indicators and hematological parameters. In serum biochemistry, aspartate aminotransferase(AST) was significantly decreased and sodium content was increased in the 2,000 mg/kg male group, while chlorine was significantly decreased in the 2,000 mg/kg female group. Also, albumin, total cholesterol and total bilirubin were significantly increased in the 2,000 mg/kg male and female group. In histopathological examinations, centrilobular hepatocellular hypertrophy in the liver was observed in the 2,000 mg/kg male and female groups. And pigmentation in the spleen was observed in the 2,000 mg/kg male group. In conclusion, four-week repeated oral dose of Clean Natural to rats did not cause apparent toxicological change at the dose less than 2,000 mg/kg body weight. Thus it is suggested that no-observed adverse-effect level(NOAEL) for Clean Natural in rats was considered to be 1,000 mg/kg/day.

• 한국식품위생안전성학회지
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• 제8권4호
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• pp.251-254
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• 1993

Extraction and Clean-up procedures coupled with quantitation by high performance liquid chromatography(HPLC) was evaluated for the detection of 4 aflatoxins, B1, B2, G1 and G2, in peanut butter. The Sep-pak clean-up method showed poorer separation and repeatability than did the modified DeVries' and an immunoaffinity column clean-up methods. No significant difference of detected aflatoxins between the affinity column clean-up and modified DeVries' method. The coefficients of variation for the 4 aflatoxins were ranging from 6.3∼32.3 by the modified DeVries' method and 5.3∼9.8 by the affinity column clean-up.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.324-329
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• 2005

본 연구에서 SNCR 공정에서 사용되는 NO의 농도는 500 ppm이며, 환원제로 Urea를 사용하였다. 또한 첨가제로 NaOH(sodium hydroxide), $Na_2CO_3$(sodium cabonate), $NaNO_3$(sodium nitrate), HCOONa(sodium formate), $CH_3COONa$(sodium acetrate)를 이용하여 온도와 첨가제에 따른 NO 저감 효율을 측정하고자 하였다. 이때의 NO 저감 온도의 범위는 $650-1,050^{\circ}C$이다. 환원제만 사용하였을 경우, NO의 저감 효율은 44%까지 증가하였으며, 환원제와 첨가제(NaOH)를 0.5 mol/L와 1 mol/L 사용하였을 경우, NO 저감 효율은 25%와 74%이상 증가하였다. 첨가제를 사용하지 않았을 경우보다 첨가제를 사용하였을 경우 NO의저감 효율은 증가하였다. 또한 NaOH>$Na_2CO_3$>$NaNO_3$>HCOONa, >CHCOONa 첨가제의 순으로 효율이 우수하였다. 첨가제를 사용할 경우 약 $900^{\circ}C$에서 $1,050^{\circ}C$의 온도범위에서 NO저감 효율이 65% 이상으로 나타났다. 온도 창의 범위는 약 $250^{\circ}C$의 범위로 나타났으며, 최저 효율은 약 20%이며 최대효율은 약 74%정도로 나타났다.

• 한국의류학회지
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• 제25권6호
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• pp.1037-1045
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• 2001

This research is done to design and manufacture prototype clean room garments to improve the product yield of the clean room processing. To assist the research, other papers and references on the same subject were collected for analysis. Also the researcher made interviews with the workers at the clean room. The prototype garments made for this project was compared against the commercially available clean room garments used in the industry. A set of test was conducted to measure particle release from the garments. The prototype clean room garments was manufactured after having considered all the aspects stated above, and tested for the level of particle release. The test subjects performed 4 different movements(marching, arms stretch, squat and rise, and jogging) while wearing the prototype garments and commercially available clean room garments. Particle counts produced by each movement were measured. The data collected was statistically analyzed. The followings are the result of the test. 1) Overall, the prototype garments yielded less particle release.(p<0.001) 2) It showed greatest difference of particle counts for jogging(p<0.001) and squat and rise(p<0.001). In the arms stretch test. the prototype garments was also more effective in controling the particle, however, in the marching test. no significant difference was detected. 3) The prototype garments had less particle release in upper(p<0.001), middle(p< 0.001), and lower level(p<0.01) than the commercially available clean room garments. Manufacturing a new fabric for the clean room processing is important, but this research proves that the design of the clean room garments also determines the efficiency garments in the particle control. Therefore the same fabric can perform differently according to how it is designed. Improving the design will also improve the 7article control and reduce the cost of research. Eventually, the manufacturers will increase the product yield.

• Journal of Periodontal and Implant Science
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• 제29권1호
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• pp.65-80
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• 1999

The purpose of this study was to evaluate the effects of periodontal curet and various rotating instruments on the root surfaces. Thirty-five extracted teeth with advanced periodontal disease were used. They was root planed with periodontal curet, periodontal Perio-Clean bur, periodontal Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur. To find dentinal tubule orifices on the root surface, tetracycline HCI solution was applied to the one tooth of treated each group. Then, root surfaces were investigated using scanning electron microscope. Amount of loss of cementum was evaluated by loss of tooth substance index. The results were as follows. 1. Groups treated with periodontal curet and Perio-Clean bur showed irregular surface and concavities. Concavities seemed to be lacunae of cementocyte. Other groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur showed partially opened dentinal tubule orifice. 2. Groups treated with periodontal curet and Perio-Clean bur and tetracycline HCl showed irregular surface. No dentinal tubule orifice was seen. Other groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur and tetracycline HCl showed dentinal tubule orifice with various shape and size. 3. Loss of tooth substance indices were compared between groups. There was no statistically difference between periodontal curet and Perio-Clean bur groups. There were statistically differences between periodontal curet and Roto-Perio bur, ET bur, and diamond fissure bur groups. As a result of this study, groups treated with Roto-Perio bur, resin polishing ET bur, and resin polishing diamond fissure bur showed more cementum removed than groups treated with periodontal curet and Perio-Clean bur. Therefore, in a conventional treatment for periodontal disease, it was recommended that periodontal curet or Perio-Clean bur should be used. In a treatment for regeneration of periodontal tissue, it was recommended that Roto-Perio bur, resin polishing ET bur, or resin polishing diamond fissure bur should be used

• 전자진흥
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• 제13권12호
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• pp.73-76
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• 1993

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.91-93
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• 2009

A large steel ingot needs to be larger and larger in size and an ultra high clean, no defect in quality with a low hot top ratio for the resent heavy industry. The demands are very difficult to achieve simultaneously because of their contradictive effect to each other in results. In this study, 30ton steel ingot was cast in a foundry with an optimized design parameter of cast mold and cast process conditions for the low hot top ratio, 12%. The cast ingot was analyzed in macro defect, segregations, and cleanness. No macro defect was founded in central surface of the ingot. The degree of segregation and cleanness are in the controlled range with a sound quality.