• 한국식품위생안전성학회지
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• 제23권3호
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• pp.276-283
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• 2008

국내 외 선행연구결과에 의한 어린이 출생 전 후 건강에 영향을 미칠 수 있는 주요 유해물질은 inorganic arsenic, BPA, 2,4-D, dichlorvos, methylmercury, PCBs, pesticide, phthalate, PFOA/PFOS, vinyl chloride 등으로서 국내에서도 이들을 포함한 확인 연구가 수행되어져야 할 것이다. 또한 어린이들의 행동발달과 연관된 생활환경에서의 다양한 인체노출이 확인됨에 따라 탁아소, 유치원과 같은 경우 어린이 활동공간을 대상으로 환경모니터링 및 위해관리활동도 병행되어야 할 것이다. 또한 어린이 건강에 영향을 미치는 유해물질을 중심으로 독성평가, 인체영향연구, 환경 및 인체모니터링과 위해평가를 수행하므로 유해물질의 원인-상관관계를 확인하고 사실자료에 근거한 관리정책을 반영하는 것이 바람직하다.

• 한국지반환경공학회 논문집
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• 제11권11호
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• pp.47-54
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• 2010

최근 쓰레기 매립장에 보강 및 보호 목적으로 토목섬유가 널리 사용되고 있다. 최근 연구결과, 토목섬유-흙 접촉면에서는 진행성 파괴가 발생할 수 있는데 이는 토목섬유-흙 접촉면에서 함수비, 연직응력, 화학적 요소의 영향 등 고유물성에 기인한다. 본 연구에서는 침출수 내의 산성 및 염기성과 같은 성분의 영향이 진동하중 상태에서 토목섬유-흙 접촉면의 전단강도 감소에 미치는 영향을 실내 시험을 통하여 분석하였다. 다기능 접촉면 시험기를 새로 구축하고 서로 다른 pH 조건에서 수침시킨 토목섬유와 흙시료를 이용하여 진동 직접전단시험을 수행하여 접촉면 전단두께와 화학적 요소에 의한 접촉면의 전단강도 감소를 확인하였다. 또한 접촉면 전단강도 감소를 정량적으로 표현하기 위하여 교란상태개념에 기초하여 동하중 하의 화학적 인자들에 의한 토목섬유-흙 접촉면의 정규화 교란도 함수를 파악하고 전단강도 감소 특성을 확인하였다.

• Toxicological Research
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• 제8권1호
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• pp.29-40
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• 1992

The recombinant glycoprotein, LBD-005 (Lucky R & D Center, Biotechnology)stimulates the growth of stem cells and activates the development of the hematopoietic cell in a similar manner to the naturally occurring GM-CSF. This test was conducted to investigate if LBD-005 had any effect on fertility in male and female rats. Sprague-Dawley rats(88 of each sex) bred at KRICT, were dosed subcutaneously, at a volume of 2ml/kg body weight with LBD-005 at 0, 250, 500 or 1, 000mg/kg body weight. The male rats were dosed, from 6 weeks of asge, for 60 days prior to mating.

• 한국수산과학회지
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• 제36권5호
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• pp.509-514
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• 2003

We performed the experiment to determine the effective factors, such as the initial concentration of protein, pore size of air distributor, SAV (superficial air velocity), pH, salts and temperature related to foaming characteristics. The foam height in a foam generator was increased with the increase of the initial protein concentration and the decrease of pore size. As SAV was increased, the foam height was increased, and the optimum SAV was 0.84 cm/sec. The foam height was highest in the acid region and it was increased with the increase of salt concentration of NaCl and $NaHCO_3.$ The removal efficiencies of TSS (total suspended solid) and turbidity decreased with the increase of the initial protein concentration in the batch foam separator.

• 한국정밀공학회지
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• 제15권6호
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• pp.79-89
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• 1998

In determining optimal cutting condition for face milling operation, tool wear is an important factor. For the purpose of establishing the relationship between various machining factors and tool wear, cutting tests have been performed. As a result, hardness and chemical composition of workpiece material, chemical composition and grain size of cutting tool and cutting speed have been selected as machining factors. In addition, relationship between feed rate and workpiece hardness has been observed. Prior to utilizing cutting conditions recommended by ‘Machining Data Handbook(MDH)’ as a knowledge base, an analysis for the validity of the MDH has been provided. Based on this analysis, tool life criteria applied by MDH has been modified. Finally, using MDH recommended data for neural network trainning, the results from the trained neural network for optimal cutting condition for some given workpiece and cutting tool can be used as reference cutting conditions.

• 대한화학회지
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• 제67권1호
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• pp.28-32
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• 2023

The reaction conditions optimization, including the temperature of the reaction, amount of catalyst required, and reaction time for the linoleic acids (LAs) and conjugated linoleic acids (CLAs) production by catalytic dehydration of castor oil via saponification was investigated by response surface methodology (RSM). It was confirmed that all three parameters (temperature, time, and amount of catalyst) were influential factors in isolating LAs and CLAs. When the temperature was increased, the iodine value increased, and the reaction time and catalyst amount increased. The optimal reaction conditions were: 240 ℃, 2.2 h reaction time, and 7 wt% catalyst amount. The maximum iodine value reached 156.25 with 91.69% conversion to the essential fatty acids.

• 한국토양비료학회지
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• 제48권5호
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• pp.492-498
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• 2015

The long-term changes in the soil properties are closely related to the policy direction and the national program for the soil management. In this study, chemical properties of paddy soils in Jeonnam province were investigated at four-year interval since 1999 and the factors affecting change of chemical properties were analyzed in relation to the soil management policies. Chemical fertilizers supplied to Jeonnam province reduced by 57% in 2013 as compared with 1999, and the ratio of Jeonnam province to the national fertilizer supply gradually decreased to 14.1% in 2013 from 17.6% in 1999 due to national policies to reduce use of chemical fertilizers in the 2000s. In the chemical analysis of paddy soils in Jeonnam province, pH value tended to increase gradually within the optimal range. Available phosphate and exchangeable potassium content were always higher than the optimal range and showed no significant difference since 1999. Organic matter, exchangeable calcium and available silicate content were found to be lower than average content in the whole country as well optimal range for rice cultivation in 1999, but were higher than average content in the whole country and optimal range in 2011 because of faster rate of increase in Jeonnam province than the other region since the mid-2000s. The cause of increase in organic matter, exchangeable calcium and available silicate contents is considered to be the increased use of green manure crops and by-products fertilizer as an alternatives for conventional application of chemical fertilizers and soil amendment such as silicate fertilizer for agronomic control of the disease and insect pest in rice cultivation of environmentally-friendly agriculture.

• Geomechanics and Engineering
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• 제17권5호
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• pp.465-473
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• 2019

Biocementation due to the microbially induced calcium carbonate precipitation (MICP) process is a potential technique that can be used for soil improvement. However, the effect of biocementation may be affected by many factors, including nutrient concentration, bacterial strains, injection strategy, temperature, pH, and soil type. This study investigates mainly the effect of chemical concentration on the formation of calcium carbonate (e.g., quantity, size, and crystalline structure) and unconfined compressive strength (UCS) using different treatment time and chemical concentration in the biotreatment. Two chemical concentrations (0.5 and 1.0 M) and three different treatment times (2, 4, and 8 cycles) were studied. The effect of chemical concentrations on the treatment was also examined by making the total amount of chemicals injected to be the same, but using different times of treatment and chemical concentrations (8 cycles for 0.50 M and 4 cycles for 1.00 M). The UCS and CCC were measured and scanning electron microscopy (SEM) analysis was carried out. The SEM images revealed that the sizes of calcium carbonate crystals increased with an increase in chemical concentrations. The UCS values resulting from the treatments using low concentration were slightly greater than those from the treatments using high concentration, given the CCC to be more or less the same. This trend can be attributed to the size of the precipitated crystals, in which the cementation efficiency increases as the crystal size decreases, for a given CCC. Furthermore, in the high concentration treatment, two mineral types of calcium carbonate were precipitated, namely, calcite and amorphous calcium carbonate (ACC). As the crystal shape and morphology of ACC differ from those of calcite, the bonding provided by ACC can be weaker than that provided by calcite. As a result, the conditions of calcium carbonate were affected by test key factors and eventually, contributed to the UCS values.

• 대한통합의학회지
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• 제9권3호
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• pp.79-86
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• 2021

Purpose : This study was conducted to provide fundamental data to prepare for countermeasure to protect health of workers in the dental clinics from hazardous chemical substance, and to assess effecting factors on management of Material Safety Date Sheet(MSDS) and handling of hazardous chemical substance among workers in dental clinics. Methods : This study was carried out a survey with structured self-administered questionnaire which was consisted of 7 questions about the management of MSDS, 9 questions about recognition and practice of hazardous chemical substances in dental clinics, and 7 questions about general characteristics. Total subjects of this study were 204 adult who workers in dental clinics located in Busan and Gyeng-nam province area. The collected data were analysed using the SPSS statistical package program (ver. 23.0). Results : The factor that positively affected factor on recognition and practice of hazardous chemical substances in dental clinics has experience that has been institutional health-care accreditation. The factor that positively affected the management of MSDS has experience that has been institutional health-care accreditation. Conclusion : It is necessary to prepare countermeasures such as campaign and education on cognition of general chemical substances, and also the author concern that it should be perform the education on handling of hazardous chemical substances in dental clinics for more effecting management of MSDS. In order to improve the management of MSDS and improve the awareness and safety of chemicals, it is necessary to encourage the implementation of the institutional health-care accreditation system or prepare guidelines for the management of MSDS.

• 한국가스학회지
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• 제28권1호
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• pp.35-43
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• 2024

산업 및 과학기술의 고도화로 인해 신규 화학물질 수와 사용량은 꾸준히 증가하고 있으며 이에 따른 화학물질 안전관리의 중요성이 사회적으로 부각됨에 따라 국민적 요구가 높아지고 있다. 정부적인 차원에서 화학물질의 안전관리에 대해 부처별로 역할을 구분하여 관리하고 있으나 시설 노후화 및 취급 부주의 등의 문제로 매년 화학물질로 인한 사고가 빈번하게 발생되고 있는 실정이다. 국내에서 발생한 화학물질 관련 사고사례를 바탕으로 사고 유형을 분석한 결과, 누출·폭발·화재·기타 등의 순으로 사고가 발생하고 있으며 사고의 원인은 시설결함, 안전관리 미준수로 순으로 분석되었다. 본 연구에서는 화학물질 중 불산을 취급하고 있는 사업장을 대상으로 HAZOP을 통해 취급공정에 대한 유해위험요인을 파악하여 Bow-Tie를 활용한 위험성평가를 수행하였다. 본 연구 결과를 바탕으로 동종·유사 사업장의 화학사고 예방을 위한 안전관리 계획을 개선할 수 있을 것이며 이를 통해 화학사고를 사전에 예방할 수 있는 화학안전관리 체계의 선진화에 기여할 수 있을 것으로 기대된다.