• Journal of Mechanical Science and Technology
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• 제20권3호
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• pp.358-365
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• 2006

The hydraulic pump of an Electro-hydrostatic Actuator should be able to quickly feed large volume of oil into hydraulic cylinder in order to reduce the response time. On the other hand, it should be also able to precisely dispense small amount of oil through low-speed operation so that the steady state position control error of the actuator can be accurately compensated. Within the scope of axial piston type hydraulic pumps, this paper is focused on the investigation how the surface treatment of their cylinder barrel with TiN plasma coating can contribute to the reduction of the friction and wear rate of valve plate in the low-speed range with mixed lubrication. The results showed that the friction torque of the valve plate mated with a TiN coated cylinder barrel could be reduced to 22% of that with an uncoated original one when load pressure was 300 bar and rotational speed 100 rpm. It means that the torque efficiency of the test pump was expected to increase more than 1.3% under the same working condition. At the same time, the wear rate of the valve plate could be reduced to $40\sim50%$.

• 한국안광학회지
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• 제12권4호
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• pp.9-14
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• 2007

본 논문에서는 매년 증가되는 안경광학과 입학정원 증가에 따른 문제점들을 연구하였다. 주된 문제는 안경사 인력의 과잉공급과 열악한 근무환경에 기인하며 이를 해결하기 위해서는 안경사 인력의 수적 불균형을 해소하겠다는 관계자 모두의 공통된 정책적 시각을 가져야 한다. 또 보건의료 인력의 수요와 공급을 예측하고 정확한 정책을 수립하기 위해서는 보건의료 인력개발을 담당할 상설기구와 중장기적인 계획이 필요하다. 안경사 인력의 질적 불균형의 해소를 위해서는 정확한 직무 영역을 설정하고 전문교육과정을 재편하며 국가고시 실기평가의 방법을 구체화하며 보수교육의 내용과 방법을 혁신해 가야 한다.

• 한국대기환경학회지
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• 제11권2호
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• pp.185-190
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• 1995

Recently, because of the worse of the air pollution, the excessive airtught of building and the inferiority of air conditioning system, the development of high efficiency air purification technology was enlarged to the environmental improvement of an indoor or a harmful working condition. The air purification technology has used chemical filters or charcoal filters or charcoal to remove hazardouse gaseous pollutants (SO$_{x}$, NO$_{x}$, NH$_{3}$, etc.) by air pollutant control technology, but they have many problems of high pressure loss, short life, wide space possession, and treatment of secondary wastes. For these reason, the object of reasearch shall be hazardous gaseous pollutants removal by the surface discharge induced plasma chemical process that is A.C. discharge of multistreams applied A.C. voltage and frequency between plane induced eletrode and line discharge eletrode of tungsten, platinum or titanium with a high purified alumina sheet having a film-like plane. As a result, the control performance for hazardous gaseous pollutants showed very high efficiency in the normal temperature and pressure. Also, after comtact oxidation decomposition of harmful gaseous pollutants, the remainded ozone concentration was found much lower than that of ACGIH or air pollution criteria in Korea.rea.

• 한국화재소방학회논문지
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• 제21권4호
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• pp.72-80
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• 2007

화재원인을 과학적으로 규명할 수 있는 화재조사자를 양성하기 위해서는 전문적이고 체계적인 교육프로그램 개발과 반복적인 재교육이 가장 중요한 인자이다. 본 연구는 화재조사교육과정의 운영상 문제점 등에 대하여 설문조사를 통하여 분석하고 국내 외 화재조사 전문교육기관의 교육과정 운영 실태 등을 비교 분석하여 교육효과에 영향을 미칠 수 있는 교육과정, 교육방법, 교육생 선발 방법 및 효과적인 활용방안 등의 문제점에 대한 해결방안을 제시하였다.

• 전기학회논문지
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• 제60권3호
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• pp.584-587
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• 2011

In this work, the $TiO_2$ and $SnO_2$ thin films as blocking layers were coated directly onto the metal-mesh electrode surface to prevent unnecessary inflow of back-transfer electrons from the electrolyte ($I^-/I_3^-$) to the metal-mesh electrode. The DSCs were fabricated with working electrode of SUS mesh coated with blocking $TiO_2$ and $SnO_2$ layers, dye-attached mesoporous $TiO_2$ film, gel electrolyte and counter electrode of Pt-deposited F:$SnO_2$. From the experimental result, it was ascertained that the efficiency of metal electrode coated with $TiO_2$ by Dip-coating was superior to that of metal electrode coated with $SnO_2$ by Dip-coating and screen printing with the results of experiments. The photo-current conversion efficiency of the cell obtained from optimum fabrication condition was 3% ($V_{oc}$=0.61V, $J_{sc}$=11.64 mA/$cm^2$, ff=0.64) under AM1.5, 100 mW/$cm^2$ illumination.

• 한국항해항만학회지
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• 제32권10호
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• pp.829-835
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• 2008

본 연구의 목적은 컨테이너터미널에서 사용되는 다기능 이송차량을 위한 2단계 배차전략을 제시하는 것이다. 2단계 배차는 실시간 위치 제어를 사용하여 이송차량과 크레인간의 대기시간을 절감시키기 위한 방법이다. 배차 1단계는 실시간 위치정보를 바탕으로 목적지 위치를 할당하는 것이며, 기존의 실시간 배차에서 이용되는 방식에 모니터링을 보안한 것이다. 배차 2단계는 이송차량의 싣기, 놓기, 집기 등의 기능을 작업장소의 작업상황에 따라 선택하여 작업지시를 내리는 것이다. 다기능 이송차량의 2단계 배차전략은 하역시스템의 대기시간을 감소시켜 생산성 향상에 기여할 것이다.

• 한국응급구조학회지
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• 제19권2호
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• pp.99-115
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• 2015

Purpose: This study aimed to provide basic data for clinical training program development by analyzing the operating conditions and satisfaction in a clinical training program for 119 emergency medical technicians (EMTs) in South Korea. Methods: Data from 84 EMTs were collected on June 19, 2014. We administered a 64-item questionnaire about operating conditions and satisfaction in the clinical training program, and analyzed data (SPSS v 21.0). Results: The degree of performance in the field, importance of the item in the field, and level of difficulty were 3.36, 4.23, and 3.21, respectively. In the number of times that an item was directly performed according to the subjects' general characteristics a statistically difference in sex (p = .000), duty (p =.021), and total working time of trainees (p = .002). The subjects' total satisfaction score was 3.77. The difference in satisfaction according to the subjects' characteristics was a statistically significant in terms of sex (p = .016) and clinical training area (p = .005). Conclusion: A more efficient training system for hospital clinical training courses should be developed. The operation condition analyzed in this research may contribute to the improvement of the performance of EMTs.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.101-111
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• 2021

To improve the potential of single chamber microbial fuel cells (SCMFCs) as an applicable technology, the main challenge is a practical application for larger scales bioenergy production from potent exoelectrogenic microorganism with real dairy wastewater. To increase power generation, three individual MFCs were together operated in series best under the fed batch condition for 15 days. The volume of MFC 1 and MFC 2 is "300 mL" and MFC 3 is "500 mL" respectively. The individual MFCs 1, MFC 2 and MFC 3 gives an open circuit voltage of 0.60 V, 0.66 V and 0.55 V and result in total working voltage when connected in series of 1.745V, which lead an LED to glow. The maximum power densities obtained from MFC 1, MFC 2 and MFC 3 are 62 mW/㎡, 50 mW/㎡ and 45 mW/㎡ (normalized to the surface area of the anodic electrode, which was 50 ㎠ for all three MFCs), and corresponding to current densities of 141 mA/㎡, 155 mA/㎡ and 123 mA/㎡, respectively. Therefore this work suggests the cheapest way to connect microbial fuel cells in series to gain power with the lowest operating cost and chemical oxygen demand (COD) removal.

• 대한설비공학회지:설비저널
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• 제4권4호
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• pp.275-284
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• 1975

By the experiment of a model Ondol heating system gas flow characteristics in a briquette flue tube was investigated. As a heat source electric heater was used, which renders steady flow condition of air. working fluid. It was observed that the flow augumentation may be obtained by increasing the vertial elevation of the flue tube, namely increase in the tube length or increase in the tube inclination, and the gas temperature at the tube entrance Among several factors which augument the flow rate slope of the flue tube has the most striking effect and then the temperature of gas entering the tube. Increase in length of the tube also auguments the flow but the rate of augumentation is so small that it gives little assistance to improvement of the flow The flow in a briguette flue gas does not essentially satisfy the one dimensional steady flow assumption. It is also observed that the flow begins to accompany irregular velocity fluctuation as inclination of the tube increases.

• 여성건강간호학회지
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• 제10권3호
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• pp.190-199
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• 2004

This thesis explores the actual circumstances of Korean nursing by investigating its present situations. Ultimately, the intent of this study aims to establish a future direction of Korean Nursing. As such, the current conditions of Korean nursing is analyzed in the following categories: education, practice, research, nursing policy, expansion of nursing field, and entrepreneurship. In the final conclusion, an appropriate orientation of the future of Korean nursing is discussed. There are two primary Nursing programs, a three-year(63) and a four-year(53), in Korean Nursing education. Master's programs are available at 32 nursing schools or 32 professional graduate schools. A total of 15 nursing schools have a doctoral program in Korea. The ratio of graduates between the three-year and four year programs is 76:24. Hence, it is highly encouraged to expand four-year nursing programs, because it will help raise the social status of nursing professionals as well as the quality of nursing. In the clinical nursing field, independency and self regulation are critical. As such, organizational change, implementation of a standardized nursing m information system, appropriate workforce, and improvement of the reimbursement system in nursing is recommended. In community nursing, the following should be resolved to provide better nursing services: improvement of working condition and benefits, establishment of a law enforcing the hiring of nurses, and providing continuing education. The number of nursing research has increased and nursing studies are in great quantity. However, research in practices and theories are more in demanded. Hence, research that integrates theories and practices are very significant. Ultimately, it is critical to support nursing studies that will influence nursing policy. The Korean Nurses Association(KNA) is an organization that supervises the nation's nursing policy. The primary focus of KNA is to combine the three and four year undergraduate education systems into 4 years and to establish the Nursing Practice Act. The Ministry of Health and Welfare has adapted a system to educate and certify nurse specialists in 10 nursing areas in 21 nursing graduate schools expecting high-quality nursing services and a decrease of cost. The government also allowed nurses to operate facilities for health management or welfare agencies.