• 보존과학연구
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• 통권31호
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• pp.43-57
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• 2010

This study intends to provide quantitative data about the extraction characteristics of major elements of earthenware by executing soaking test of cleaning agents. It aims at providing basic data for the stability assessment when applying the cleaning agents for conserving earthenware. The data will be extracted from the analysis of co-relationship between the physical characteristics and the ion extraction characteristics. XRD analysis displayed that AT-1, AT-2 and AT-3 which did not generate mullite were fired at lower than 1,000 whereas AT-3 and AT-5 that included mullite were higher than 1,000. The degree of absorption was AT-4 > AT-2 > AT-1 > AT-3 > AT-5 in order and the correlation between the degree of absorption and firing temperature of earthenware displayed a positive correlation. Extraction amount of oxalic acid which was used for the removing iron oxide was AT-1 > AT-2 AT-4 > AT-3 > AT-5 in order. and the ion extraction data displayed that there is a positive correlation with absorption level. However AT-1 and AT-2 which were fired at lower temperature showed that there was no correlation between the ion extraction characteristics and absorption level. Ion extraction of citric acid produced little amount compared with the one of oxalic acid, yet it caused less damage to earthenware than oxalic acid when it applied. The result of ion extraction level in the absorption test displayed that Fe had higher level than in Si, Al from the test for both oxalic acid and citric acid. Based on the regression analysis of the data from the previous studies, the physical characteristics of the earthenware and ion extraction level, further studies will be conducted on the predicting technique on the extraction characteristics of major elements of earthenware samples for the conservation in future.

• 한국환경보건학회지
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• 제47권5호
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• pp.462-471
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• 2021

Background: The number of synthesized chemicals has rapidly increased over the past decade. For many chemicals, there is a lack of information on toxicity. With the current movement toward reducing animal testing, the use of toxicity big data and deep learning could be a promising tool to screen potential toxicants. Objectives: This study identified potential chemicals related to reproductive and estrogen receptor (ER)-mediated toxicities for 1135 cleaning products and 886 laundry products. Methods: We listed chemicals contained in cleaning and laundry products from a publicly available database. Then, chemicals that potentially exhibited reproductive and ER-mediated toxicities were identified using the European Union Classification, Labeling and Packaging classification and ToxCast database, respectively. For chemicals absent from the ToxCast database, ER activity was predicted using deep learning models. Results: Among the 783 listed chemicals, there were 53 with potential reproductive toxicity and 310 with potential ER-mediated toxicity. Among the 473 chemicals not tested with ToxCast assays, deep learning models indicated that 42 chemicals exhibited ER-mediated toxicity. A total of 13 chemicals were identified as causing reproductive toxicity by reacting with the ER. Conclusions: We demonstrated a screening method to identify potential chemicals related to reproductive and ER-mediated toxicities utilizing chemical toxicity big data and deep learning. Integrating toxicity data from in vivo, in vitro, and deep learning models may contribute to screening chemicals in consumer products.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3895-3901
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• 2009

본 연구는 전문가치면세정술 및 구강보건교육이 구강청결도와 구강보건행태에 미치는 영향을 검증하는데 목적이 있다. 연구는 교육 군별 교육효과를 비교하기 위해 대조군 (80명-구강보건교육), 실험군 (80명-구강보건교육과 전문가치면세정술)으로 분류하여 진행하였다. 잇솔질 횟수, 잇솔질 시간, 점심식사 후 잇솔질 실천율, 구강위생용품 사용률, 구강청결도의 변화를 각 교육 군별로 비교 분석한 결과는 다음과 같다. 잇솔질 횟수의 변화는 두 교육군 모두 증가하였으나 개별전문가치면세정술과 구강보건교육을 시행한 실험군에서만 통계학적으로 유의한 행태변화를 나타냈다. 점심 식사 후 잇솔질 실천율의 변화는 두 교육 군 모두 증가하였으나 개별전문가치면세정술과 구강보건교육을 시행한 실험군의 증가가 더 높았고, 구강청결도의 점수는 대조군보다 실험군에서 더 높게 조사되었다.

• 한국정보과학회논문지:시스템및이론
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• 제27권6호
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• pp.567-582
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• 2000

본 논문은 로그파일시스템의 원리를 바탕으로 플래시메모리 저장시스템에 적합한 플래시메모리 공간 관리 방법을 제안한다. 플래시메모리는 비휘발성, 빠른 입출력 속도 등의 장점을 지니고 있지만, 제자리 덮어쓰기(in-place update)가 불가능하고 메모리 셀에 대한 쓰기(write) 횟수가 제한되는 단점이 있다. 이러한 특성은 플래시메모리를 저장 매체로 사용할 때 기존의 저장 매체 관리 방법과는 다른 방법을 요구하게 된다. 본 논문은 자유 공간유지를 위해 필요한 클리닝 메커니즘의 연산 비용을 낮추면서 동시에 저장공간이 전체적으로 균등하게 사용될 수 있도록 하는 사이클 평준화 기법을 제안한다. 제안된 방법은 특히 메모리 활용도와 로컬리티가 높을 때 좋은 성능을 보인다. 클리닝 메커니즘은 자주 접근되지 않는 COLD데이타를 그렇지 않은 데이타와 격리시킴으로써 그 효율이 향상되었으며, 사이클 평준화는 사용 횟수간의 최대 차이가 하드웨어적인 오차를 벗어나지 않는 수준까지 이루었다. 실험을 통해 제안된 방법은 비교 기준으로 삼은 직관적 방법(greedy policy)에 비해 사이클 평준화가 잘 이루어진 상태에서 최대 35%정도의 클리닝 비용 절감 효과를 보였다.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2013년도 추계 학술발표논문집
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• pp.28-29
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• 2013

We have been measuring $CH_4$ flux in a rice paddy in Gimje using the eddy covariance method since July 2011. In order to measure the fast fluctuations of $CH_4$ concentration, an innovative LI-7700 open-path laser spectrometer is used. This high-precision, low power, light weight, low maintenance sensor enables us to operate it on a continuous and long-term basis. One particular feature, among other things, is the self-cleaning lower mirror which decreases maintenance requirements while ensuring more robust, continuous, high-quality dataset. Its cleaning is initiated at user-specified time intervals or a signal strength threshold, and its status is recorded as a diagnostic index. We have noticed that the operation of LI-7700 at Gimje site is quite challenging particularly due to its frequent mirror cleaning requirement and the associated sensitivity of the instrument. In this presentation, we present some field observation data regarding the mirror cleaning and their analysis, thereby suggesting the pertinent operation options for high-quality, maximum data retrieval in the field.

• 한국물환경학회지
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• 제33권2호
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• pp.123-129
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• 2017

The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.

• 한국학교ㆍ지역보건교육학회지
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• 제18권3호
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• pp.55-68
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• 2017

Objectives: Republic of Korea has entered an aged society, recently. As chronic diseases increase, elderly inpatients has been increasing and they have used caregivers for convenience. Accordingly, this study aims to investigate the oral health knowledge and attitude of caregivers on oral health management of elderly inpatients, which would affect the general health and quality of life. Methods: A survey questionnaire was distributed to the caregiver(n=165), at a neurosurgery or orthopedic hospital inpatient ward in Seoul, Gyeonggi-do from April 1 to 14, 2017. We analyzed the data with descriptive statistics analysis, chi-squared analysis and logistic regression analysis by using SPSS 23.0. Results: The response rate to the questionnaire was 92%. Oral health management provided by caregivers to inpatients in the elderly was prevention of oral diseases(92.8%), tooth brushing (89.5%), use of oral care products(68.4%), denture cleaning(90.8%) and oral cleaning(90.8%). Frequency analysis of oral health management in accordance with the educational needs of caregivers was all confirmed statistically significant(p<0.05). In the logistics regression model, oral health knowledge was significantly associated with low oral cleaning(OR=1.58) and oral health attitude was significantly associated with high denture cleaning(OR=1.29) and oral cleaning(OR=1.28) after adjustment for other covariates including gender, age, certification, education level, ward, working years. Conclusions: It is necessary to expand the scope and improve the quality of education that can change the attitudes and behaviors of the caregivers on the oral health management of the elderly on the basis of the current oral health education.

• 한국입자에어로졸학회지
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• 제18권4호
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• pp.129-136
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• 2022

The line width of circuits in semiconductor devices continues to decrease down to a few nanometers. Since nanoparticles attached to the patterned wafer surface may cause malfunction of the devices, it is crucial to remove the contaminant nanoparticles. Physical cleaning that utilizes momentum of liquid for detaching solid nanoparticles has recently been tested in place of the conventional chemical method. Dropwise impaction has been employed to increase the removal efficiency with expectation of more efficient momentum exchange. To date, most of relevant studies have been focused on drop spreading behavior on a horizontal surface in terms of maximum spreading diameters and average spreading velocity of drop. More important is the local liquid velocity at the position of nanoparticle, very near the surface, rather than the vertical average value. In addition, there are very scarce existing studies dealing with microdroplet impaction that may be desirable for minimizing pattern demage of the wafer. In this study, we investigated the local velocity distribution in spreading liquid film under various impaction conditions through the CFD simulation. Combining the numerical results with the particle removal model, we estimated an effective cleaning diameter (ECD), which is a measure of the particle removal capacity of a single drop, and presented the predicted ECD data as a function of droplet's velocity and diameter particularly when the droplets are microns in diameter.

• 한국산업보건학회지
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• 제33권4호
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• pp.427-438
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• 2023

Objectives: This study aims to create a safer working environment by examining the working environment of cleanroom cleaning workers through a survey and comparing the differences in perception between workers and managers. Methods: The survey was written based on the working environment and the safety and health management system. In order to improve the quality of the study, we visited the sites in person and conducted an in-depth interview. SPSS Statistics 26 (IBM, USA) was used to analyze the data. Results: Based on the survey, differences were found in chemical used, MSDS sharing methods, risk factors during cleaning work, work environment measurement results, special health examination items, places considered dangerous, and work. Conclusions: It is necessary that there be different work environments and risk factors for cleanroom cleaning workers at respective workplaces. As a result of the survey, there was found to be a difference in perception between workers and managers, and both workers and managers should try to reduce this difference.

• 근관절건강학회지
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• 제31권1호
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• pp.42-52
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• 2024

Purpose: This study aimed to identify the factors affecting compliance with personal protective equipment (PPE) use among medical device reprocessing staff. Methods: This descriptive cross-sectional study included 163 cleaning staff members from ten general hospitals in Seoul and Gyeonggi. Data were collected using self-report questionnaires administered between July and September 2023. Analysis included t-tests, ANOVA, Pearson's correlation coefficient, Bonferroni correction, and multiple regression, conducted using SAS ver.9.4. Results: Statistically significant differences in compliance with PPE were found based on department and exposure to contamination within six months (t=-2.82, p=.007). Attitudes toward PPE (r=.22, p=.006) and awareness of the safety climate (r=.22, p=.006) showed a statistically significant positive correlation with PPE compliance. Factors influencing use of personal protective equipment by cleaning staff during medical device reprocessing were department, compliance with PPE, and awareness of the safety climate. The explanatory power of these factors was 58.0%. Conclusion: Improving PPE compliance and creating a safe cleaning environment entails fostering a supportive safety climate. Additionally, regular training that takes into consideration the characteristics of the cleaning staff, alongside continuous monitoring, is required.