• Clean Technology
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• v.2 no.1
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• pp.22-31
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• 1996

• Journal of Environmental Health Sciences
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• v.31 no.5 s.86
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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.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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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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• v.21 no.3
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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.

• Journal of Food Hygiene and Safety
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• v.8 no.4
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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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• v.43 no.2
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• pp.324-329
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• 2005

The efficiency of reducing nitric oxide using urea combined with alkali salt additives is reported in this study. The inlet concentration of NO is 500 ppm with air flow rates of 3 and 5 L/min. Reduction of NO was studied from 650 to $1,050^{\circ}C$ with urea concentrations of 0.3 to 1 mol/L. The efficiency for the reduction of NO increased by 44% when urea is added alone. A further increase in efficiency was observed in the presence of NaOH as additive in fact, the efficiency was increased by more than 25% and 75% when 0.5 mol/L and 1 mol/L NaOH were added with the urea. The efficiency for the reduction of NO increased with all additives, but descended in the order NaOH, $Na_2CO_3$, $NaNO_3$, HCOONa, and CHCOONa. The maximum efficiency of NaOH and $Na_2NO_3$ are 74% and 73%, respectively. All these additives did not alter the comparatively wide operating temperature window for reducing NO. However, sodium compounds do not shift the maximum NO concentration towards lower temperatures when the NO removal activity enhances.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.6
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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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• v.29 no.1
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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

• Journal of Korean Electronics
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• v.13 no.12
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• pp.73-76
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• 1993

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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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.