• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.2
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• pp.127-135
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• 2009

Reid and Kajiura(1957) has studied on the wave damping rate over a permeable bed of infinite depth. In this study, wave damping rate over a permeable bed of finite depth is derived by linear wave theory. It is then extended to derive wave damping rates over a double or triple layer, each of which consist of different material. Applying the wave damping rate to the mild slope equation, the wave transmission coefficient over a permeable bed has been calculated. The model has been certificated by comparing with the result of Flaten and Rygg(1991)'s integral equation method in the case of a single-layer bed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.946-953
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• 2012

When water shortage has been getting worse recently, toilet water-saving is one of the most effective way to solve the water shortage. Therefore, in this study, toilet flushing performance was investigated with VOF(Volume Of Fluid) model to obtain the basic design data for the development of high-efficiency toilets. The result showed that the shorter trapway, the longer the flushing duration time. However, the shorter trapway is found to have disadvantage in exhausting dirt due to relatively weak siphon and higher curvature. Since the remaining water in a trapway appears to help siphon, it is also an important factor in developing high-efficiency toilets. Although higher water level in the water tank shows better performance in flushing, lower water level is preferred to save water. Too low water level may cause dirt to clog the trapway due to relatively weak siphon.

• Korean Journal of Pharmacognosy
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• v.14 no.4
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• pp.149-160
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• 1983

It has been known that Gentianae macrophyllae Radix is reputed to be effective in removal of 'Pungseub' and 'Heoyeol', and to be analgesic. Since ancient times, however, there have been many examples of substituting Lycoctoni Radix for Gentianae macrophyllae Radix. For that reason, this experiment was conducted to compare the diuretic, analgesic, anti-inflammatory, anti-pyretic, anti-bacterial effect, and toxicity of Lycoctoni Radix with those of Gentianae macrophyllae Radix. The results obtained in this work were summarized as follows; In the test of acute toxicity, Lycoctoni Radix was found to be toxic in comparison to Gentianae macrophyllae Radix which was found to be non-toxic. Both herbs were found to be diuretic and Gentianae macrophyllae Radix was more effective than the other and to be ineffective for the blood pressure and respiration. Lycoctoni Radix was found to be more analgesic than the other. Gentianae macrophyllae Radix was found to be more anti-inflammatory of the two and both demonstrated anti-pyretic effect. Anti-bacterial effect was detected only in Lycoctoni Radix. It is concluded that Gentianae macrophyllae Radix has mild diuretic, analgesic, anti-inflammatory and anti-pyretic effect, but Lycoctoni Radix, due to its toxicity, can not be substituted for Gentianae macrophyllae Radix.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.10 s.241
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• pp.1392-1398
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• 2005

API 581 guideline provides a methodology for calculating the risks of equipments in refinery or petrochemical plant. However, especially in part of the consequence of failure, there is a major limitation of its application to the petrochemical plant directly since only a representative material is considered in calculating the risk while the equipment is composed of numerous materials. The objectives of this paper are to propose an enhanced risk-based inspection (RBI) technique to resolve shortcomings inclusive of the above issue and to assess the risks of typical petrochemical equipments. In this respect, a program incorporating material database was developed to fully incorporate the characteristics of different materials. The proposed RBI program consists of qualitative, semi-quantitative and quantitative risk evaluation modules in which toxic materials as well as representative materials were selected automatically for comparison to those in the current guideline. It has been applied to assess the risks of equipments in ethylene facilities of petrochemical plants. Thereby, more realistic evaluation results were obtained and applicability of the proposed RBI program was proven.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.35-38
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• 2004

Global competitive pressures are asking industrial companies to find the best way to meet their customer's requirements, reduce the costs of products, and increase productivity. Quality improvement has been proposed and implemented as a primary means of achieving these purposes. The quality improvement usually includes a goal of reducing the costs due to poor quality. While these costs of poor quality (COPQ) are not known precisely, they are known to be very high. Also, they may be underestimated by the hidden costs due to non-value activities, such as potential lost sales, costs of redesign due to quality reasons, and extra manufacturing costs due to defects, etc. In any manufacturing or service operation, all actions and resource expenditures of a company should be focused on creating value for customers. Any activity or resource of not creating the value for customers could be regarded as waste, which consequently causes the COPQ. Some companies did use dashboards to understand and identify value added or non-value added activities in order to reduce or eliminate wastes. These dashboards must be properly designed to consider inherent differences in manufacturing or service operations among business organizations. In addition, a structured quality improvement program such as the Six Sigma must support these dashboards. In this paper, a case study of designing dashboards for evaluating and reporting the COPQ in business units is presented.

• Environmental Analysis Health and Toxicology
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• v.13 no.3_4
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• pp.95-104
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• 1998

INTRODUCTION : Arsenic is a ubiquitous element present in various compounds throughout the earth's crust. The use of arsenic compounds increased greatly during the 18th and 19th centuries, including its use in pigments and dyes, as a preservative of animal hides, in glass manufacture, agricultural pesticides, and various pharmaceutical substances. The causal association between human arsenic exposure, usually in the form of inorganic compounds containing trivalent arsenite (As$^{III}$) or pentavalent arsenate (As$^V$), and various forms of human cancer has been known for many years.

• The Korean Journal of Emergency Medical Services
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• v.16 no.2
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• pp.75-89
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• 2012

Purpose : This research was designed to provide basic data for advanced pre-hospital airway management by comparing the time to ventilation and success rate for tracheal intubation performed with Macintosh laryngoscope and intubating Laryngeal Mask Airway(ILMA) in a manikin. Methods : All participants were novice users among EMT-Paramedic students and were divided into two groups: (1) the group for Macintosh laryngoscope guided tracheal intubation(MLG-TI) (2) the group for ILMA guided tracheal intubation(ILMA-TI). After an introductory lecture and demonstration, each group made an attempt ten tracheal intubation to compare the ventilation time and success rate for tracheal intubation. Results : 1) There was significant difference in the time to ventilation through MLG-TI, the time to first and second ventilation through ILMA-TI of the 10 attempts. 2) The time to first ventilation through ILMA-TI was significantly shorter than that of ventilation through MLG-TI. 3) There was no significant difference between the time to ventilation through MLG-TI and the time to second ventilation through ILMA-TI. 4) The success rates of ILMA-TI were significantly higher than those of MLG-TI. Conclusion : ILMA-TI can be an alternative method for MLG-TI in advanced pre-hospital airway management.

• The Korean Journal of Emergency Medical Services
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• v.16 no.3
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• pp.19-28
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• 2012

Purpose : The present study was designed to provide basic data for advanced pre-hospital airway management by comparing the insertion time and success rate between laryngeal tube suction II (LTS II) and laryngeal mask airway (LMA) in a manikin. Methods : A total of 32 participants were novice users to both of devices among paramedic students. After taking the introductory lecture and demonstrations, the participants made an attempt to insert the LTS II and LMA to compare the insertion time and success rate. They marked the easiness of insertion of the score ranged from 1 to 10 score scale and preference of the two devices. Results : The insertion time of the LTS II was significantly shorter than that of the LMA (p =.000). There was no significant difference between LTS II and LMA in the success rate. In the easiness of insertion, the score of LTS II $(8.47{\pm}1.41score)$ was significantly higher than that of LMA $(7.19{\pm}1.98score)$(p =.001). The preference of LTS II (75%) was much higher than that of LMA (25%). Conclusion : The manikin study data showed that the LTS II may be a good alternative airway device for providing and maintaining a patent airway.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1311-1312
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• 2007

본 논문에서는 YBCO coated conductor(CC) 의 접합연구와 접합된 선재의 응용을 위한 특성연구를 수행하였다. 최근에 지속적으로 연구 개발되어 본격적으로 응용이 시작되는 CC는 기본적으로 높은 인덱스 값과 자기장에 대한 임계전류의 균일성 등 다른 고온초전도에 비해 좋은 특성을 갖고 있으며 따라서 미래의 초전도 기기에 광범위하게 사용될 것으로 예상된다. CC와 같은 초전도 선재가 초전도 기기에 적용되는 경우 대부분 초전도 선재와 초전도 사이의 접합, 초전도 선재와 상전도체 사이의 접합 등의 접합들이 존재하게 된다. 접합을 위해서는 접합 땜납이 들어가게 되고 이 부분에서 저항이 발생하게 되어 손실이 발생하게 된다. 이러한 손실은 저항이 '0'이어서 손실이 적다는 초전도기기의 장점을 떨어뜨리는 요인이 될 수 있다. 따라서 CC의 접합 특성을 연구 하는 것은 초전도 기기의 성능향상에 도움을 줄 수도 있는 요인이 될 수 있다. 이 논문에서는 구리 안정화층, YBCO 층, 완충층과 기판층으로 이루어진 YBCO CC 선재를 이용하여 두 가지의 접합 방법을 이용하여 접합특성을 연구하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.136-136
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• 2010

$Ge_2Sb_2Te_5$ (GST)는 광학 스토리지 및 PRAM(Phase-change Random Access Memory)에 적용 가능한 대표적인 상변화 물질이며 상변화 거동에 대한 다양한 연구가 진행되고 있다. 차세대 비휘발성 메모리로 각광을 받고 있는 PRAM의 경우 저전력 그러나 향후 고집적, 고성능 PRAM 소자구현을 위해서는 Reset 전류 감소를 통한 소비 전력 감소, 인접 셀간의 'cross talking'을 방지할 수 있는 열적 안정성 개선 등의 문제점들을 해결해야 한다. GST 물질의 전기적, 열적 특성을 조절하여 이러한 문제를 해결하기 위하여 GST 물질에 이종의 원소를 첨가하는 연구가 활발히 진행되고 있으며, 특히 질소 첨가에 의해 결정 성장 억제를 통한 결정화 온도 증가, 결정질의 저항 증가 등의 보고가 있었다. 본 연구에서는 질소를 첨가한 N-doped $Ge_2Sb_2Te_5$ (NGST) 박막의 상변화 거동을 규명하고 GST 박막과 비교하여 첨가된 질소의 영향을 분석하고자 한다. D.C Magnetron sputtering 방법으로 증착된 GST와 NGST 박막을 등온으로 유지하여 각 온도별로 열처리 시간 증가에 따른 비저항을 실시간으로 측정하여 GST와 NGST 박막의 상분율을 계산하고 Kissinger 모델을 이용하여 effective activation energy ($E_a$)를 구하였다. GST와 NGST 박막의 $E_a$는 각각 $2.08\;{\pm}\;0.11\;eV$와 $2.66\;{\pm}\;0.12\;eV$로 계산되었다. 따라서 첨가된 질소에 의해 NGST 박막의 결정화를 위하여 GST 박막의 경우보다 더 큰 활성화 에너지가 필요하다.