• Journal of Welding and Joining
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• v.7 no.2
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• pp.60-69
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• 1989

The present study was aimed at investigating the effect of welding parameters such as welding current, electrode force(or squeeze force) and parts cleaning on the sound weld, and establishing the most reliable weld conditions for HWP(Heavy Water Reactor) fuel end capping with the resistance upset butt welding. Major results obtained are as follows. 1. The amount of sound weld was increased with increasing weld current(5.0-11KA) because the activated diffusion with increasing heat generation played an important role in eliminating the porosity and weld line in the weld interface. 2. It was found that weld current was not significantly influenced by the electrode force although the increase of it caused a slight increase of weld current and upset deformation. 3. Acetone rinsing before drying for the Zircaloy-4 end cap cleaning produced the reliable sound weld because it would remove the remaining solvent and surface films, and provided the uniform contact between the end cap and the tube. 4. The optimum welding conditions for fuel end capping by a resistance upset hytt welding are obtained as follows. weld current: 10-11KA, electrode force: 62-90KPa parts cleaning: vapor degreasing.rarw.water, acetone rinsing.rarw.drying.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.37-37
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• 2019

Cryopreservation is one of the ideal and suitable methods for long-term storage of plant germplasm. The plant contaminated with diseases and pathogens are decreased the multiplication rate, survival rate and high quality of plants after cryopreservation. The aim of this work was to improve a micropropagation method for lily in Korea, which are cultivars and indigenous plant. In the last process of rinsing scales after surface-sterilization, we tried to control the diseases and pathogens lived within the tissue by rinsing in 0.03% sodium hypochlorite (NaClO) instead of sterile distilled water. Bulb scales of Lilium were cultured in vitro on MS medium supplemented with Plant Preservative Mixture (PPM). The newly small bulb formed from bulb-scales was transferred to MS medium. We checked the non-contamination and survival rate after 2 weeks in culture. Non-contamination was shown to be 70 to 90% in formed small bulbs. This study will help to mitigate microbial contamination in Lilium species micropropagation for cryopreservation.

• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.3
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• pp.525-545
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• 2021

The purpose of this study was to assess the sustainability of laundry practices among Korean households in comparison with European households. A total of 329 responses were collected through an online survey and analyzed using SPSS. Detergent dosing, use of fabric softener, prewashing, rinsing, washing programs, and washing temperatures of Korean households were not optimal for sustainability. Only 11.2% of respondents followed dosage instructions while the majority based on load size. Use of fabric enhancer, prewashing, and rinsing were frequent. Cotton 40℃ was the most frequently used program (81.5%) while eco and cold wash programs were among the least (1.5%). In terms of laundry sorting, load size, drying, and ironing, more sustainable actions were reported. Laundry was often sorted by color, machines were commonly filled, and clothes tended to be air-dried and not excessively ironed. Gender was the primary socio-demographic factor denoting sustainable habits, with males being more attentive to instructions and care labels than females. European households, however, were more sustainable in all areas except for frequent ironing, and education level and employment status were significant factors affecting sustainable practices.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.557-564
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• 2015

The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-$CO_2$ (supercritical-$CO_2$) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-$CO_2$. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-$CO_2$ without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, $25^{\circ}C$) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, $5^{\circ}C$, we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-$CO_2$ (7.5 Mpa, $40^{\circ}C$), we had as good results as those of the case using gas-$CO_2$. Besides the processing time was shortened compared with that of the case of using gas-$CO_2$.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.659-667
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• 2000

Quality attributes of fresh-cut green onion(Allium fistulosum L.) as affected by rinsing and packaging were investigated in terms of flesh weight, color, viable cell counts, sensory properties during storage at $10^{\circ}C$. Fresh green onions were trimmed, cut, and rinsed with cold water(approximately $5^{\circ}C$) as well as chlorine solution(100 mg/L) and then packaged in low density polyethylene film pouches of $63\;{\mu}m$ thickness. Rinsing treatments with cold water or chlorine solution did not significantly influence changes in microbial populations but sensory characteristics, resulting in cut green onions of better visual quality as compared to the control without rinsing. Fresh-cut green onions were also rinsed with cold water and packaged in sealed bags of low density polyethylene films with different thickness(22, 36, $63\;{\mu}m$), and stored at $10^{\circ}C$ for 18 days. Thickness of polyethylene film was a significant factor for microorganisms populations and sensory attributes. Mesophilic aerobic bacterial count after 13 days for the control, packed in punched film bags, was $3.07{\times}10^6}$ CFU/g, while those for samples in hermetically sealed bags ranged only $1.74{\sim}2.02{\times}10^5}$ CFU/g. Gas composition within the sealed packages changed from normal air to about $1.3{\sim}5.4%\;O_2$ and $4.0{\sim}8.0%\;CO_2$ after 13 days of storage. Particularly, the visual sensory quality of cut green onion samples was retained better in polyethylene film bags of $63\;{\mu}m$ thickness(gas transmission rate: 600 $O_2\;mL/day{\cdot}m^2{\cdot}atm;\;2,500\;CO_2\;mL/day{\cdot}m^2{\cdot}atm$) than in the others.

• Journal of the Korean Society of School Health
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• v.13 no.2
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• pp.331-340
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• 2000

Primary school is regarded as an important period when many health-related behaviors and life-styles begin to be formed. Acquiring them through school heath education has a strong influence on the health promotion of not only the family but also the community. The objectives of this study were to evaluate current oral health care of elementary schools in Chungnam province and to provide information for further development in elementary school oral health. We performed a questionnaire survey to 280 health teachers and among them, 155 teachers answered. The result of this study were as follows: 1. Sixty five percent of the health teachers had little interest in oral health. Major information sources for teaching oral health were books in 58.1% of the 155 teachers and 83.2% of teachers spent 30 minutes to 1hour per day in oral health care practice for the students. 2. Contents of the oral health education were composed of regular and special curriculums, and an average of education time during a semester was 2.6 hours in 3rd grade, and 1.3 hours in first and second grade. 60.6% of the teachers made the children practice the proper method of tooth brushing during the education time. 3. Major problems in oral health education were insufficient time, lack of equipment and difficulty in teaching method. The educational media were tooth models among 91.0% and OHP among 85.2% of the teachers. The tooth model was usually used in first to fourth grades and OHP in fifth to sixth grades. But 63.9% health teachers need to develop stronger educational methods using multimedia. 4. Meanwhile the most important strategy of oral health in urban schools was health education, that of rural schools was fluoride mouth-rinsing programme. Fluoride mouth-rinsing programmes were performed by 60.0% of the elementary school. Periodic dental examination was performed in all elementary schools. 98.2% of the schools sent the results home through school notification letters, but post-examination management was performed in only 67.1% of them 64.5% of the health teachers do follow-ups on the oral disease of the children after the examination. Only 0.7% of the schools have oral health education plans for the students' parents. Considering these major strategies for elementary school oral health care were health education, practicing proper methods of tooth brushing, periodic dental examinations, and fluoride mouth-rinsing programmes. But health teachers need more time for oral health education, practicing and management, and developing education materials. With regard to the high demand for oral health education and poor follow-up after periodic examination, the oral health education in elementary school should be considered as a formal educational course for more proper management of oral health, including application of major strategies to the children in earlier grades and efforts for increasing recognition and participation of the parents.

• Journal of Oral Medicine and Pain
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• v.36 no.4
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• pp.245-252
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• 2011

The aim of this study is to clinically evaluate the effect of a mouthwash containing cetylpyridinium and zinc chloride on reduction of morning oral malodor in healthy subjects measured by organoleptic measurement and a portable sulfide monitor. A total of 8 healthy non-smoking male volunteers were enrolled in this study of crossover design consisting of two experimental phases. The subjects were instructed to rinse the mouth with 10 mL of the experimental mouthwash containing cetylpyridinium and zinc chloride for 30 seconds at the first phase. At the second phase after a one-week washout period, each subject rinsed with distilled water as a control. All experiments were conducted at around 8:30 a.m. and oral malodor was measured using organoleptic measurement and a portable sulfide monitor just before rinsing with the experimental mouthwash or control (baseline), 1 hr, 2 hrs, and 3 hrs after rinsing. The mouthwash containing cetylpyridinium and zinc chloride reduced morning oral malodor up to 3 hrs after rinsing. Organoleptic score and concentrations of volatile sulfur compounds after use of the experimental mouthwash significantly decreased with time, and the decreases were significantly different between the mouthwash and control. In conclusion, the mouthwash containing cetylpyridinium and zinc chloride is significantly effective on reduction of morning oral malodor in healthy subjects by 3 hrs.

• 대한예방의학회:학술대회논문집
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• 1995.10a
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• pp.383-384
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• 1995

• Resources Recycling
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• v.11 no.5
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• pp.21-23
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• 2002

A new process based on the co-precipitation method was developed fer removing harmful impurities during Mn-Zn ferrite production such as $SiO_2$ and P from waste pickle liquor. By this process a final result of less than 100 ppm of $SiO_2$ and less than 10 ppm of P content in the ferric oxide is easily attained. Though Ca cannot be removed by this process, water rinsing of the ferric oxide is effective fer reducing Ca content to less than 100 pm. For further purification, the origins of each impurity must be investigated and then taken away.

• 대한예방의학회:학술대회논문집
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• 1996.10a
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• pp.261-262
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• 1996