• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.63-69
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• 2010

This study was conducted to compare the concentration of various air contaminants in nine different laboratories during routine activities. Volatile organic compounds (VOC) were sampled and analyzed using NIOSH Method 1500 and asbestos fibers were sampled and analyzed using NIOSH Method 9002 and 7400. Detectable levels of acetone, toluene and ethanol were found in all the laboratories and xylene and n-hexane were detected in eight of the nine laboratories. All the VOC concentrations were well below the Korean Ministry of Labor's Exposure Limit and American Conference of Governmental Industrial Hygienists' (ACGIH) Threshold Limit Values (TLVs). Total VOC concentrations at the university laboratories were significantly higher than those at governmental agency laboratories. Airborne fiber concentrations were below 0.01 fibers/cc, while the concentration of chrysotile was 2% in insulation materials sprayed on the ceiling of one laboratory. While all the governmental agency laboratories (n=4) had fume hoods, two out of the five university laboratories did not have fume hoods. The capture velocity of half of the fume hoods were below the maintenance standard(0.4 m/sec). In conclusion, the study suggests that the current controls in place at both university and government agency laboratories are not sufficient in limiting exposure to harmful chemicals to non-detectable levels, though they appear to be adequate in protecting workers to levels below applicable occupational exposure limits. The study also suggests that researchers working in university laboratories may be exposed to greater levels of contaminant than those working in government agency laboratories.

• Journal of the Korean Applied Science and Technology
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• v.20 no.1
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• pp.72-79
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• 2003

The impregnated activated carbons were prepared by the incipient wetness method with the contents of $KIO_3$ varied from 1.0${\sim}$10 wt% as the impregnation material. The specific surface area and micropore volume of the rice hulls activated carbon were $2,600{\sim}2,800$ $m^2$/g and 1.1${\sim}$1.4 cc/g, respectively. With increasing the contents of impregnation materials, the surface area and micropore volume decreased by 3${\sim}$21%. However, The amounts of hydrogen sulfide adsorbed increased by 2.1${\sim}$2.8 times depending on the impregnation content. The optimum contents of $KIO_3$ were 2.4 wt%. Although the breakthrough time and adsorption capacity of hydrogen sulfide decreased with increasing temperature in the case of the unimpregnated activated carbons, they increased by 1.2${\sim}$ 3.2 times for the case of the impregnated activated carbons. The optimum aspect ratio(L/D) was 1.0 and the adsorption amount of hydrogen sulfide enhanced with increasing the gas flow rate. The regeneration temperature was determined as 400$^{\circ}C$ from the TGA experiment. The adsorption capacity of hydrogen sulfide with the impregnated activated carbon decreased gradually as the regeneration continued. The hydrogen sulfide adsorption amount of the regenerated activated carbon up to 4 times was still higher than that of the unimpregnated activated carbon.

• Korean Journal of Community Nutrition
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• v.18 no.2
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• pp.142-153
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• 2013

The purpose of the study was to examine nutritional management and nutritional care demands of home-visit care service and the nutritional status of serviced elderly. The survey was carried out from $5^{th}$ to $21^{st}$ of January, 2011 among 37 In-Home Service institutions. The number of elderly surveyed by 143 care helpers was 281. Analysis was performed for 203 subjects (male: 44, female: 159). The age distribution was from 50 to 99 years. The grading by long-term care insuranceshowed 18,2% on level 1 and 2, and 81.8% on level 3. For the disease treatment, the proportion of implementing diet treatment turned out to be very low. The proportion of subjects living with their children was 45.3%, and living alone was 29.1%. The proportion of home-visit care among types of In-Home Service was 70%. Subjects who needed additional necessary diet management service turned out to be 40.9%. Diet management was the most necessary services from all levels. MNA (specifiy MNA) scores were significantly (p < 0.001) associated with BMI, mid-arm circumference (MAC), calf circumference (CC), intake problems, and weight loss during the last 3 months. For studied elderly, 45.3% were malnourished, and 46.8% were at the risk of malnutrition by MNA score. Based on the result of this survey, the nutritional care was not systematic on the In-Home Service. Prevention and management of the disease was much better than the treatment to improve the quality of life. We conclude that nutrition management is necessary for the elderly. To improve nutritional status of elderly in home care services, systematic nutrition management should be implemented.

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.87-100
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• 1997

Clinical Observation was made on 29 cases of Hypertensive intracerebral hemorrhage patients in the ICU of In-Chon Oriental Medical Hosptital of Dongguk University from October in 1994 to June in 1996. The observation are ability in daily life(ADL) of patients by Location and Type of Hemorrhage, Amounts of Hematoma, Graeb's Score, Intraventricular Hemorrhage, States 4th Ventricle, Surrounding Edema around the Hematoma, Middle Line Shift, Age, Level of Consciousness. Pupillary Light Reflex and Treatment Modalities. Our conclusions on Prognostic Factors using Computerized Tomographic Findings and Ability in daily Life(ADL) Evaluation in patients with Hypertensive Intracerebral Hemorrhage Patients are as follows. A variety of prognostic factors that influence ADL5+6(%) were observed. 1. ADL5+6($\%$) of total cases was 34.9%. The prognosis were unfavorable when high Graeb score(P<0.05), dilated 4th ventricle(P<0.01), much surrounding edema around the hematoma (P<0.05), unilateral unreactive or both unreactive pupillary light reflex(P<0.05). 2. There was no difference of ADL5+6(%) in both hypertensive basal ganglionic and thalamic intracerebral hemorrhage. 3. The prognosis gets poorer as the volume of hematoma is more than 16cc. But there was no difference of ADL5+6(%) in each group. 4. The prognosis gets poorer in cases with IVH than without IVH. But there was no difference of ADL5+6(%) in each group. 5. The prognosis gets poorer as the middle line shift is more than 6mm. But there was no. difference of ADL5+6(%) in each group. 6. The prognosis gets poorer as the level of consciousness is more than drowsy. But there' was no difference of ADL5+6(%) in each group.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.114-121
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• 2014

Liquefied natural gas(LNG) cargo containment system(CCS) has the primary function of ensuring both adequate structural safety with respect to sloshing load which is defined as a violent behaviour of the liquid contents in CCS due to external forced motions and thermal insulation keeping natural gas below its boiling point. Among different LNG CCS types such as independent B-type and membrane ones, Mark III CCS is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex, reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated composite structure showing complex structural behaviour under external load. Advanced finite element models of Mark III CCS plate is generated and used in conjunction with ultimate strength based failure criteria from laminated composite mechanics for the strength assessment. The strength assessment is performed within the initial failure state of Mark III CCS plate. Results provide failure details such as failure locations and loads. Finally obtained results are reviewed using the loads from acceptance criteria suggested by classification.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.497-497
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• 2007

활성탄소를 양쪽 전극에 사용하는 전기이중층 커패시터는 고출력 특성과 반영구적인 cycle 수명인 장점을 가지고 있는 반면, 단위 중랑 또는 부피 당 용량이 작아 메모리 백업용 보조전원으로서의 활용에 그치고 있다. 이를 보완하기 위하여 최근에는 앙쪽의 전극에 충방전 메카니즘을 달리하는 비대칭 전극 설계기술을 기반으로 하는 하이브리드 커패시터가 개발되었고, 에너지밀도로서는 유기계 전해액에서 약 15-20 Wh/kg를 가지는 것으로 보고되고 있다. 본 연구메서는 양극의 활성탄소에 비용량이 상대적으로 큰 LiCo02 분말을 혼합한 하이브리드 전극의 제조 및 전기화학적 특성을 조사하였다. 이때 $LiCoO_2$ 분말의 혼합 종량비의 영향에 의한 전극 부피 당 용량(mAh/cc)의 변화와 $LiCoO_2$ 분말의 입자 크기에 의한 하이브리드 전극의 출력 특성을 조사하였다. $LiCoO_2$ 분말은 불밀을 이용하여 입자크기를 조절하였고, 각각의 입자크기를 가지는 LiCoO2 분말을 활성탄소와 함께 혼합하여 혼합 활물질 : Carbon black : PTFE의 중량비가 90 : 5 : 5가 되도록 sheet 전극을 제조하였다. 제조한 전극을 양극에, Li foil을 음극에, 전해액을 LiPF6 in EC DMC를 사용하여 코인셀을 제조하고 전기화학적 특성은 MACCOR 충방전기를, AC 저항은 AC impedance를 각각 사용하여 평가하였다. 활성탄소에 $LiCoO_2$ 분말의 첨가 중량비가 증가할수록 전극 부피 당 용량은 증가하였으나, 원료 상태의 $LiCoO_2$ 분말의 첨가에서는 코인셀의 전극 저항은 첨가 중량에 따라 단순 증가하였다. 그러나 미세 $LiCoO_2$ 분말을 첨가할 경우, 20%의 첨가에서 전극 저항은 활성탄소 만을 사용한 전극과 동등한 전극저항을 나타내고 충방전 cycle 특성도 개선되는 것을 확인하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.11
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• pp.1-7
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• 2020

Recently, hydrogen has gained considerable attention as an eco-friendly fuel, which helps in reducing carbon dioxide content. Specifically, there is a growing interest in vehicles powered by a hydrogen fuel cell, which is spotlighted as an environmental-friendly alternative. A hydrogen transport system, fuel cell system, fuel supply system, power management system, and hydrogen storage system are key parts of a hydrogen fuel cell truck. In this study, a hydrogen storage system is built and analyzed. The expansion length of the storage vessel at maximum operating pressure (87.5 MPa) was calculated with ABAQUS, and then the optimized system was designed and built. The leak and bubble tests were performed on the built storage system. The leakage of the system was measured to be under 5 cc/hr. Hence, it can be used as a research test for the safety evaluation of leading systems of hydrogen fuel-powered commercial vehicles.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.405-411
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• 2020

Objectives: The objectives of this study were to investigate whether airborne fibers were released to the outside air from the asbestos removal area in buildings, and to confirm the existence of asbestos fibers in samples using transmission electron microscopy(TEM). Methods: A total of 1,295 samples was collected from inside and outside 155 asbestos removal areas. To investigate the release of asbestos fibers from the removal area, samples were collected at three locations, such as an entrance to change room, an exit of negative pressure unit(NPU) and perimeter areas. Samples were also collected in the removal area prior to and after removal activity. All samples were analyzed by phase contrast microscopy(PCM) and one-tenth of the samples was analyzed using TEM to discriminate asbestos fibers. Results: During the asbestos removal activity, 27(4.1%) of 662 samples collected outside the removal area showed airborne fiber concentrations equal to or in excess of 0.01 f/cc, the permissible emission standard of the Korean Ministry of Environment. Further, 111 samples were analyzed using TEM. The distribution of asbestos fiber concentrations was log-normal. It was found that 51 of 111 samples(46%) contained asbestos fibers. Conclusions: There is a potential risk of asbestos exposure among neighbors and the public outside the asbestos removal areas. It is recommended that the asbestos removal work be conducted strictly following the specifications required by government and/or professional organizations.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.99-119
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• 2007

The USB flash drive is common used for portable storage. That is able to store large data and transfer data quickly and carry simply. But when you lose your USB flash drive without any security function in use, all stored data will be exposed. So the new USB flash drive supported security function was invented to compensate for the problem. In this paper, we analyze vulnerability of 6 control access program for secure USB flash drives. And we show that exposed password on communication between secure USB flash drive and PC. Also we show the vulnerability of misapplication for initialization. Further we develop a protection profile for secure USB flash drive based on the common criteria version 3.1. Finally, we examine possible threat of 6 secure USB flash drives and supports of security objectives which derived from protection profile.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.157-166
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• 2021

Forecasting dam inflow based on high reliability is required for efficient dam operation. In this study, deep learning technique, which is one of the data-driven methods and has been used in many fields of research, was manipulated to predict the dam inflow. The Long Short-Term Memory deep learning with Sequence-to-Sequence model (LSTM-s2s), which provides high performance in predicting time-series data, was applied for forecasting inflow of Soyang River dam. Various statistical metrics or evaluation indicators, including correlation coefficient (CC), Nash-Sutcliffe efficiency coefficient (NSE), percent bias (PBIAS), and error in peak value (PE), were used to evaluate the predictive performance of the model. The result of this study presented that the LSTM-s2s model showed high accuracy in the prediction of dam inflow and also provided good performance for runoff event based runoff prediction. It was found that the deep learning based approach could be used for efficient dam operation for water resource management during wet and dry seasons.