• 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 Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.15-20
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• 2002

The Hydroxyethyl methacrylate(HEMA) was developped in 1960's and later the use of contact lenses increased. At present more and more people use RGP contact lenses. Due to the wide range of optical corrections available and due to their high oxygen transmission Japanese and Korean people like them. Nevertheless one of nine CL users(beginners) stopped wearing the CL within the first year. We conducted a survey to evaluate the level of patient compliance in lens care and maintenance and to assess practitioner knowledge of contact lens information. Generally 6% of contact lens wearers drop out per year. The aim of this research was to find out what opticians can do to reduce the drop-out rate by getting information on handling, on general data of the patient and on optical prescription. Lens wearer were asked to complete a 10 question survey that focused on lens care-wear modality, lens replacement, storage, symptoms and case disinfection. There were total 180 participants in the study. Most of contact lens wearers have an inadequate understanding of contact lens care system. Therefore, it is important that contact lens specialists place more emphasis on practitioner education about general contact lens fields and reinforce patient education during the dispensing visit.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.401-406
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• 2000

Spilling of petroleum hydrocarbons such as gasoline, motor oils, and diesel fuel from underground storage tanks (USTs) is a major source of contamination to ground water and soils. In response to the need of developing an effective and economical cleanup technique, this study investigates the effectiveness of using sonication to enhance the soil flushing method. The study involves laboratory testing, and the testing was conducted using a specially designed and fabricated device to determine the effect of sonication on contaminant removal. The sonication was applied at 20 kHz frequency under different power levels. Test soil was Joomoonjin Sand, and diesel fuel was used as a contaminant of soil flushing test. The results of the investigation show that sonication enhanced the contaminant removal from soils significantly, and the degree of enhancement varied with power levels of sonication. Based on the results of the study, it is concluded that the flushing method with sonication has a great potential to become an effective method for removing petroleum hydrocarbons from the contaminated ground.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.523-530
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• 2007

Background: A ThinPrep$^{(R)}$ Processor was developed to overcome the limitations of conventional cytology and is widely used to diagnose various cancers. This study compared the diagnostic efficacy of conventional cytology for lung cancer with that of the ThinPrep$^{(R)}$ cytology using the bronchial washing fluid. Methods: The bronchial washing fluid of 790 patients from Jan. 2002 to Dec. 2006, who were suspected of gaving a lung malignancy, was evaluated. Both ThinPrep$^{(R)}$ and conventional cytology were performed for all specimens. Result: Four hundred forty-six men and 344 women were enrolled in this study, and 197 of them were diagnosed with cancer from either a bronchoscopic biopsy or a percutaneous needle aspiration biopsy. ThinPrep$^{(R)}$ cytology showed a sensitivity, specificity, positive predictive value, negative predictive value and false negative error rate of 71.1%, 98.0%, 92.1%, 91.1%, 8.9%, respectively. The conventional cytology showed sensitivity, specificity, positive predictive value, nagative predictive value and false negative error rate of 57.9%, 98.0%, 90.5%, 87.5%, 12.5%, respectively. For central lesions, the sensitivity of conventional cytology and ThinPrep$^{(R)}$ were 70.1% and 82.8%, respectively. Conclusion: ThinPrep$^{(R)}$ cytology showed a higher sensitivity and lower false negative error rate than conventional cytology. This result was unaffected by the histological classification of lung cancer. Therefore, ThinPrep$^{(R)}$ cytology appears to be a useful method for increasing the detection rate of lung cancer in bronchial washing cytology test.

• Journal of the Korean Geotechnical Society
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• v.28 no.11
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• pp.79-86
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• 2012

Cemented soils have been used for subbase or base materials of roads, backfill materials of retaining walls and cofferdam. Such cemented soils can be degraded due to repeated wetting and drying or various weathering actions. Unlike rocks, a standard method was not defined for evaluating the durability of cemented soils. In this study, a slaking durability test and an ultrasound cleaner were used for developing a new durability test method for cemented soils. For durability tests, cemented sands with different cement ratios (4, 6, 8, and 12%) with cylindrical specimens were prepared and then air cured or under-water cured for three days. Three-day-cured specimens were dried for one day and then submerged for one day before testing. The weight loss after the slake durability test or ultrasonic cleaner operation for 10 or 20 min was measured and used for assessing durability. When a cement ratio was 4%, the weight loss from ultrasonic cleaner test was 7-25% but that from slake durability test was as much as 30-60%. For specimens with cement ratio of more than 8%, the weight loss was less than 10% from both tests. A durability index increased with increasing a cement ratio. The durability index of under-water cured specimen was higher than that of air cured specimen. The ultrasonic cleaner test was found to be an effective tool for durability assessment of cemented sands rather than the slake durability test.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.466-466
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• 2011

가상수는 Allan에 의해 1993년 처음 도입된 개념으로 모든 재화나 서비스를 생산하기 위하여 사용된 물의 양( /kg)을 의미한다. 예를 들어 1차 농산물의 경우 생육기간동안 농산물이 필요로 하는 물의 양이 가상수로 사용되고, 가공품의 경우 가공과정을 거치며 소비되는 물의 양이 가상수에 포함된다. 이러한 가상수의 개념을 활용한 소비 기반 물사용 지표가 물발자국이며 이는 2002년 Hoekstra에 의해 도입되었다. 물발자국은 개인이나 지역, 집단 등이 소비하는 재화와 서비스를 생산하는데 필요한 물의 총량을 나타낸다. 우리나라와 같은 물 부족 국가에서는 농 축산물 관련 정책의 수립 시 정량적인 생산량뿐만 아니라 소비되는 물의 양도 동시에 고려할 필요가 있다. 특히 현 정부는 2015년 식량자급률 목표치(곡물자급률 25%, 육류자급률 71%)를 설정하여 농 축산물의 생산 및 수입량을 조정하고자 한다. 이러한 식량자급률의 목표치에 따라 국내 생산 및 수입량의 비율이 변화하게 되므로 국내 물발자국의 값도 변화하게 되며 이는 수자원 정책 수립 시 주요한 요인으로 작용할 수 있다. 그러므로 식량자급률의 변화에 대해 단순히 생산량의 관점뿐 아니라 물 소비 절약의 관점에서의 접근이 필요하다. 이에 본 연구에서는 2015년 정부의 식량자급률 목표치 달성을 위하여 각 품목별로 소비되는 가상수의 양을 정량적으로 산정하고, 국내적으로 소비 또는 절약되는 가상수의 양을 추정하고자 하였다. 추정된 결과를 바탕으로 식량자급률 목표치에 따른 생산량의 조정으로 인한 물발자국의 변화와 그 영향을 파악하고자 하였다. 본 연구를 위하여 식량 자급률 목표치 설정에 포함된 농 축산물의 단위 가상수량과 생산량 추이, 목표 생산량 등을 조사 하였다. 이중 곡물의 단위 가상수량은 국내의 실정을 적용한 국내 연구결과를 활용하였으며, 축산물의 단위가상수량은 음용, 세척을 위한 원단위 필요수량과 소비되는 사료의 재배를 위한 단위 가상수량을 활용하여 전체 축산물의 가상수량을 산정하였다. 조사, 산정된 자료를 활용하여 2015년 식량자급률 목표치 달성을 위해 필요로 하는 가상수의 변화량과 국내적으로 소비 또는 절약되는 가상수의 양을 파악하고자 하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.104.1-104.1
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• 2013

스테인레스강 진공용기의 기체방출률을 낮추기 위해 구연산을 사용하여 화학세척한 후 진공 중 산화처리(VTO)하였다. 1E-11 mbar 이하의 극고진공에 도달하기 위해서는 진공펌프의 성능 뿐 아니라 진공 용기 자체로부터 지속적으로 방출되는 수소의 양을 줄이는 것이 중요하다. 스테인레스 강의 경우 잘 형성된 표면의 크롬산화막이 수소 방출을 억제하는데 효과가 있다고 알려져 있다. 구연산은 스테인레스 강의 표면 철 성분을 감소시키므로 상대적으로 크롬 비율을 증가한다. 이렇게 표면의 크롬 비율이 증가한 상태로 VTO 처리하면 보다 순수하고 균일한 크롬산화막이 형성될 것으로 기대할 수 있다. 본 발표에서는 구연산 +VTO 처리한 스테인레스 강(SST304) 진공 용기의 기체방출률 측정결과에 대해 논의하고자 한다.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.199-208
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• 2007

Three pesticides commonly used in perilla leaf were subjected to a field residue trial to ensure safety of terminal residues in the harvest. The residual patterns of three pesticides, which were dimethomorph, indoxacarb and procymidone were examined after applying with the recommended and double dose and their DT50 were calculated. Also degradation patterns of pesticides at storage $4^{\circ}C$ were compared to those at $20^{\circ}C$, and removal rates of pesticides by washing perilla leaf with water were measured. Biological half-lives of dimethomorph, indoxacarb and procymidone were $2.91{\sim}3.11,\;2.53{\sim}3.14\;and\;2.62{\sim}2.92$ days, respectively. During the storage period, the degradation patterns were appeared more obviously at $20^{\circ}C$ than $4^{\circ}C$. Removal rates of dimethomorph, indoxacarb and procymidone were $51.3{\sim}73.3%,\;74.1{\sim}91.3%\;and\;57.9{\sim}81.6%$by various washing methods.

• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.17-26
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• 2003

The sorption experiment of cobalt was performed after the TRIGA soil was intentionally contaminated with cobalt was found that the sorption equilibrium coeficiency of soil decontamination was high when the ratio of soil mass to the volume of citric acid becomes 1:5 The TRIGA soil contaminated with 0.01 M, 0.001 M, and 0.0001 M of cobalt solution were decontaiminated with 0.01 M citric acid. The cobalt concentrtion in the wastewater were measured to be correspondingly 36.0, 14.0, 1.5 ppm. The results of wastewater recycling experiment by chemical precipitation method revealed that corresponding cobalt removal efficiency were 97% 88%. It was shown that the removal efficiency decreases as the cobalt concentration in the wastewater decreases. During the decontamination experiment, a lot of NaOH had to be added, and the volume of final solid waste reached almost 10% of that of the contaminated soil. The result of wastewater recyling experiment by ion exchange resin meted rethod revealed that to more the strong acid resins are used, the higher the cobalt removal efficiency becomes and the cobalt removal efficiency becomes and the lower the pH of recycling wastewater become. In order to obtain more than 95% removal efficiency, more than 0.625 g of strong acid resin was necessary in each of 3 experiments. There was an unexpected problem that a lot of strong acid resin waste was produced which amounts to 9.2% (volume) of the contaminated soil.

• Journal of Naturopathy
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• v.11 no.1
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• pp.31-38
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• 2022

Background: New beauty soaps are always subject to evaluation. Purposes: This study performed a human application test and safety evaluation on the cleaning effect of the fine dust mimic of the test product, Daziwar soap bar, on 52 women. Methods: The quantitative change measured the cleaning effect of fine dust before and after washing immediately after spraying the fine mimetic dust on the forearm of 22 women. In addition, the safety was evaluated at 30 minutes, 24 hours, and 48 hours after 24 hours after applying the patch to the woman's back. Results: After one time washing with the soap immediately after spraying dust on the inside of the arm, the amount of the remaining mimetic was statistically significantly decreased in both the test group and the control group (p < .001). However, the washing rate was 99.96% in the experimental group and 75.58% in the control group. The questionnaire was evaluated as 'Good' or higher in terms of efficacy. In the evaluating of adverse reactions after washing fine dust by a dermatologist, there were no reports or observations of specific skin adverse reactions or abnormal findings in the subjects. The safety evaluation was judged as non-irritating in the skin reaction evaluation at 30 minutes, 24 hours, and 48 hours after instillation on the back for 24 hours. Conclusions: The test product, Daziwar soap, was found to be very helpful in cleaning fine dust on the human body and was found to be safe for the human body.