• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.33-40
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• 2004

Benzoyl peroxide is a High Production Volume Chemical, which is produced about 1,371 tons/year in Korea as of 2001 survey. The substance is mainly used as initiators in polymerization, catalysts in the plastics industry, bleaching agents for flour and medication for acne vulgaris. In this study, Quantitative Structure-Activity Relationships (QSAR) are used for getting adequate information on the physical -chemical properties of this chemical. And hydrolysis in water, acute toxicity to aquatic and terrestrial organisms for benzoyl peroxide were studied. The physical -chemical properties of benzoyl peroxide were estimated as followed; vapor pressure=0.00929 Pa, Log $K_{ow}$ = 3.43, Henry's Law constant=3.54${\times}$10$^{-6}$ atm-㎥/mole at $25^{\circ}C$, the half-life of photodegradation=3 days and bioconcentration factor (BCF)=92. Hydrolysis half-life of benzoyl peroxide in water was 5.2 hr at pH 7 at $25^{\circ}C$ and according to the structure of this substance hydrolysis product was expected to benzoic acid. Benzoyl peroxide has toxic effects on the aquatic organisms. 72 hr-Er $C_{50}$ (growth rate) for algae was 0.44 mg/1.,48 hr-E $C_{50}$ for daphnia was 0.07mg/L and the 96hr-L $C_{50}$ of acute toxicity to fish was 0.24mg/L. Acute toxicity to terrestrial organisms (earth worm) of benzoyl peroxide was low (14 day-L $C_{50}$ = > 1,000 mg/kg). Although benzoyl peroxide is high toxic to aquatic organisms, the substance if not bioaccumulated because of the rapid removal by hydrolysis (half-life=5.2 hr at pH 7 at $25^{\circ}C$) and biodegradation (83% by BOD after 21 days). The toxicity observed is assumed to be due to benzoyl peroxide rather than benzoic acid, which shows much lower toxicity to aquatic organisms. One can assume that effects occur before hydrolysis takes place. From the acute toxicity value of algae, daphnia and fish, an assessment factor of 100 was used to determine the predicted no effect concentration (PNEC). The PNEC was calculated to be 0.7$\mu\textrm{g}$/L based on the 48 hr-E $C_{50}$ daphnia (0.07 mg/L). The substance shows high acute toxicity to aquatic organisms and some information indicates wide-dispersive ore of this substance. So this substance is, a candidate for further work, even if it hydrolysis rapidly and has a low bioaccumulation potential. This could lead to local concern for the aquatic environment and therefore environmental exposure assessment is recommended.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.19-26
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• 2017

Concrete is a construction material with porous media and corroded steel inside affects negatively to durability and structural safety. This study aims a derivation of quantitative relationship between measured HCP (Half Cell Potential) and corrosion amount considering cover depth and W/C (water to cement) ratio. For the work, cement mortar specimens with 3 different W/C ratios and 4 different cover depths are prepared, HCPs are measured with 3 different corrosion level. HCP measurement significantly increases in the saturated condition and linear relationship is observed between corrosion level and acceleration period. With increasing corrosion level and W/C ratio, and decreasing cover depth, HCP measurement increases. Considering total corrosion level and HCP measurements, relatively low COV(Coefficient of Variation) of 0.67 is evaluated through multi-linear regression analysis, however higher COVs over 0.90 can be obtained considering level of HCP measurement. In the room condition, corrosion level can be evaluated through measured HCP in the given conditions of cover depth, W/C ratio. diameter of steel inside.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2324-2329
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• 2014

The inspection of distance to go train control system conducted only when train is in main line or inspecting line, that affects low work efficiency and hazard elements to safe operation. Before or after train operation, the interface test between on-board and wayside signal system must be conducted. In this paper, onboard signal interface inspection system based on the real-time automatic analysis of onboard system status information that is transmitted to the wayside system and the operation status check of the onboard signal device operates as a virtual train information that is transmitted to the onboard system have been proposed. And after building the inspection system to the inspecting track of Daejeon Subway Line 1, Panam Depot, the verification algorithm of proposed interface test and the results was presented. therefore, it has enhanced work efficiency to do not carry train operation of a half hour in test line to test on-board system.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.25 no.1
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• pp.6-13
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• 2014

Objectives : The aim of this study is to assess the career paths and practice patterns of child and adolescent psychiatrists in South Korea. Methods : A survey on demographic data, work environment, opinion on fellowship training program, and current practice patterns was conducted in 76/223 (34.0%) of all child and adolescent psychiatrists (N=223) were from 1980 to 2008. The survey data from the responders were analyzed. Results : More than half of those surveyed were women. The mean age of survey participants was 40.8 years; most were married, and lived in the Seoul National Capital Area. In general, the responders were very satisfied with their work. They worked in private practice, public sector, group practice, and as consultants. Up to 87% of the patients treated were children and adolescents. The most common treatment modalities were medication and parent psychoeducation. Social skills training and play therapy were applied mainly for children aged 4 to 12 years old. Cognitive behavioral therapy and counseling were preferred in adolescents. Conclusion : The current study used a database approach in order to define current practice patterns. These data may be helpful in consideration of future training programs, workforce issues in child and adolescent psychiatry in South Korea, and also in collaboration with other mental health providers.

• Korean Journal of Environmental Biology
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• v.28 no.2
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• pp.101-107
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• 2010

Metal ions are essential to life. However, some metals such as mercury are harmful, even when present at trace amounts. Toxicity of mercury arises mainly from its oxidizing properties. Ionizing radiation (IR) is an active tool for destruction of cancer cells and diagnosis of diseases, etc. IR induces DNA double strand breaks in the nucleus, In addition, it causes lipid peroxidation, ceramide generation, and protein oxidation in the membrane, cytoplasm and nucleus. Yeasts have been a commonly used material in biological research. In yeasts, the physiological response to changing environmental conditions is controlled by the cell types. Growth rate, mutation and environmental conditions affect cell size and shape distributions. In this work, the effect of IR and mercury chloride (II) on the morphology of yeast cells were investigated. Saccharomyces cerevisiae cells were treated with IR, mercury chloride (II) and IR combined with mercury chloride (II). Non-treated cells were used as a control group. Morphological changes were observed by a scanning electron microscope (SEM). The half-lethal condition from the previous experimental results was used to the IR combined with mercury. Yeast cells were exposed to 400 and 800 Gy at dose rates of 400Gy $hr^{-1}$ or 800 Gy $hr^{-1}$, respectively. Yeast cells were treated with 0.05 to 0.15 mM mercury chloride (II). Oxidative stress can damage cellular membranes through a lipidic peroxidation. This effect was detected in this work, after treatment of IR and mercury chloride (II). The cell morphology was modified more at high doses of IR and high concentrations of mercury chloride(II). IR and mercury chloride (II) were of the oxidative stress. Cell morphology was modified differently according to the way of oxidative stress treatment. Moreover, morphological changes in the cell membrane were more observable in the frequently stress treated cells than the temporarily stress treated cells.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.364-374
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• 2006

Natural ventilation technique could be the substitute for or the complement to the local exhaust ventilation system in the sense of protecting work environment. Moreover, it has many strong points ; almost no mechanical parts, no energy use and no noise. If applied appropriately, it could have the very high ventilation rate and save a lot of energy expense. But, it depends on the outdoor environment, especially temperature and wind speed/direction. Predicting the capacity of natural ventilation is not an easy job because it comes from both buoyancy and wind effect. Another problem is too much flow through the ventilator especially in winter time due to too much difference between indoor and outdoor temperature. Thus some ventilators in industries are sealed by door or plastic sheet, resulting in bad work environment. Various types of dampers are used to control the flow rate through ventilators. The capabilities of flow control by damper has not been estimated. In addition, it was not tested whether the damper could obstruct the flow through ventilator when fully opened. To answer these questions, 4 types of dampers were tested by using computational fluid dynamics. 10 different configurations includes no damper, full open and half open. Flow rates were estimated and airflow fields were analysed to clarify the before-mentioned questions. The dual type damper was the best choice for controling the capability of ventilator. In addition, the upward grill type damper was the best for not obstructing the air flow when fully opened.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.22
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• pp.49-70
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• 2004

UCP 500 has introduced new words "International Standard Banking Practice" as the basis of the examination of documents under documentary credits. However, the words have caused confusion among parties concerned with letter of credits. So, at its May 2000 meeting, ICC Banking Commission established a task force to document international standard banking practice for the examination of documents presented under documentary credits(ISBP). The publication is the product of two and a half years of work by a task force of the ICC Banking Commission. It was approved by the full Commission at its meeting in Rome in October 2002. The ISBP is a practical complement to UCP 500. It explains how the rules are to be applied on a day-to-day basis. As such, it fills a needed gap between the general principles announced in the rules and the daily work of the documentary credit practitioner. But, ISBP have two problems. First, ISBP impose more responsibilities than before the ISBP existed on banks. Second, ISBP have some problematic articles like the problem of maturity, letter of credit language, term. Consequently, all parties concerned with documentary credits need to armour themselves with knowledge for ISBP. Also, it should be noted that any term in a documentary credit which modifies or affects the applicability of a provision of the UCP may also have an impact on international standard banking practice. Therefore, in considering the practices described in this publication, parties must take into account any term in a documentary credit that expressly excludes or modifies a provision in an article of the UCP.

• Korean Journal of Community Nutrition
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• v.7 no.3
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• pp.361-372
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• 2002

The purpose of this study was to investigate the operation and management systems of the school food services in Korea and to provide useful data for improving the quality of the school food services. This study was conducted in school food service operations nationwide using a written questionnaire. The questionnaires were mailed to the dieticians of three types of school food service systems-conventional, commissary, and joint-management. Of the 660 schools that participated in this study, the responses from 212 conventional system, 212 commissary system and 200 joint-management system services were selected for analysis. Statistical analysis was performed utilizing the SAS/Win 6.12 program so as the provide a descriptive statistics. The main results of this study can be summarized as follows: The average number of meals served per day was 1014, 738 and 695 in the conventional food service, the commissary food service and the joint-management flood service systems, respectively. Over half (58.9%) of food service facilities were utilizing computer programs for their operations. Most of the commissary flood service systems (52.4%) had a satellite school and served a maximum of 2000 meals per day. In most of the joint-management food service systems (87.1%), the number of food service schools managed was two and a maximum of 3330 meals were sewed. Only one dietician was posted irrespective of the school food service system. The mean hours of work by the dietician per day was 8.9, 8.6 and 8.6 in the conventional food service, the commissary flood service and the joint-management food service systems, respectively. The principal work functions of cook personnel were cooking and cleaning.

• Korean Journal of Human Ecology
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• v.17 no.1
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• pp.171-179
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• 2008

This study focuses on 130 estheticians currently working in and around Daegu and Gyeongbuk region, in order to find out the current state of affairs and side effects related to aromatherapy. This paper is based on a survey. SPSS win 11.0 program was used for the analysis of descriptive statistics and independent t-test. According to the result of analysis, about 33% of the estheticians have had allergy experience. And in terms of installation of an air ventilation fan, which is the most important facility in an treatment room, more than half (50.8%) replied they did not have one. There was a statistically significant difference between those estheticians suffering from allergy and those who did not, in symptoms of stuffy nose/rhinitis (P<0.01) and dry skin/itchiness (P<0.5). (Allergy symptoms from the 33% of estheticians were limited to those which occurred after he or she began career) On work related symptoms, those who had work history at hospitals/clinics or apothecaries were compared. A statistically relevant difference was confirmed between those estheticians with therapy experience and those who had none, in all symptoms except headaches and drowsiness/weariness. In other words, there was difference in symptoms such as dryness of skin/itchiness (P<0.01), stuffy nose/rhinitis, dry throat, tension/nervousness, dizziness, tired eyes(P<0.5), nausea, having trouble with focusing, and fatigue(P<0.1). Those estheticians who had a history of treatment especially suffered most from dryness of skin and itchiness. The rate of regular check-ups and the use of masks, employed for self protection, was lower than average (amounting to 5 points), with the use of masks especially having the lowest average (1.7) points.

• Journal of Environmental Science International
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• v.18 no.11
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• pp.1199-1206
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• 2009

Obesity affects various kinds of adult diseases and is a principal cause of injuring people's health. Physical activities are very important to solve the obesity problem and green spaces are good place to take physical activities. In order to examine the utilization of green spaces for physical activities to improve health, the survey was implemented in regards to recognition of health, forms of use of green spaces for physical activities. Only 8.1% of respondents didn't care about health, but 91.9% of them were interested in health more than 'commonness'. 95.2% of respondents knew that obesity has an effect on various adult diseases, and 93.1% of respondents cognized that it's possible to prevent obesity by doing physical activities. More than half of respondents replied that the types of green spaces utilized for physical activities were small-scale neighborhood parks and mini parks around house. About 70% of respondents took walking as a type of physical activities. 53% of respondents utilized green spaces one or two times a week, while 25% of them utilized the places at least three times a week to take physical activities. 91.8% of respondents took exercise for more than 30 minutes. These results are expected to promote health because many experts encourage people to take physical activities at least three times a week because fats of human body begins to bum after 30 minutes from start of physical activities. In the utilizing time of green spaces, evening or after work(56.7%) was higher than morning or before work(35.1%). 71% of respondents usually visited green spaces by walking. This study shows green spaces are good places for physical activities and have boundless potentialities improving people's health.