The small coastal vessel registered in Korea, small coastal vessels with a gross tonnage of 10 tons or less account for 94.6 % and among them, aged vessels over 16 years age indicate 40.6 %. In order to reduce GHG emissions from small coast vessels, discussions are underway to replace aging ships' propulsion units with eco - friendly propulsion facilities, and the electric propulsion ship is emerging as one of the measures. The electric propulsion system using the DFE rectifier, which was applied in the conventional large commercial vessel, was effective in reducing the harmonics and improving the DC output voltage of the DC link stage, but it occupied a large volume and caused an increase in the overall system price. Therefore, in this paper, we propose an electric propulsion system using AFE rectifier with a small volume of system that can be applied to a small coastal vessel. In order to analyze the effectiveness of the overall system, the load profile was applied to obtain accurate and rapid speed tracking performance of the propulsion motor affected by the speed load. In addition, the power factor and total harmonic distortion factor of the voltage and current on the improved power output side are derived through simulation.

현재 해수담수화 공정은 지속적인 연구를 통해 많은 개발이 이루어지고 있다. 그중 전기흡착탈이온(EAD) 공정은 이온교환막을 이용한 전기투석법과 이온교환수지를 이용한 이온교환수지법을 혼합하여 이루어지는 공정이다. 보다 효율적으로 이온교환이 이루어질 수 있는 공정이지만, 이온교환막 사이에 이온교환수지가 들어가기 때문에 사이즈가 비교적 크다. 또한, 이온교환수지의 크기 분포와 당량비가 모듈의 성능에 영향을 준다. 본 연구는 현재 상용화되고 있는 이온교환공정에서 쓰이고 있는 모듈의 문제해결과 성능 향상을 위해 보다 이온교환용량이 향상된 고분자와 현재 쓰이고 있는 일반적인 이온교환수지가 아닌 더 작고 균질한 이온교환능력을 가진 이온교환 나노입자를 제조하여 제막을 진행하였고, 다양한 특성평가가 이루어졌다.

A study has been conducted on the structural analysis to reduce the light weight of the electric vehicle rotor shaft. ANSYS Static Structural was used for structural analysis. For weight reduction, the solid shaft was converted into a hollow shaft. The yield strength of the existing material SCM 440 is 655MPa, but to increase its safety, the yield strength is changed to 1,030MPa with SCM822H. At this time, weight reduction of about 47% was achieved. The resonance frequency of the rotor shaft was determined by vibration analysis and the structural safety was analyzed.

본 연구에서는 서로 다른 열전달 특성을 가진 탄소섬유 전기발열체와 경유온풍난방기가 온실 내부의 온습도, 에너지소비, 작물생육 등에 미치는 영향을 분석하기 위해 오이 재배 단동온실에 대한 난방 비교시험을 수행하였다. 전기발열체 온실에서 난방용량이 온실 환경과 난방기 운전에 미치는 영향을 분석하기 위해 온실에 6, 9, 16kW의 전력을 각각 공급한 결과 전기발열체 ON-OFF 주기는 각각 9, 11, 15회로 비례하여 증가하였으며 온실 내부 평균온도는 각각 15.2, 15.3, 15.6oC, 평균상대습도는 84, 81, 76%로 나타나 난방 용량이 클수록 온실내부 온도는 높고, 상대습도는 낮게 나타났다. 또한 6, 9kW 가동 시 하부온도가 상부보다 0.1oC 높았으며 16kW 가동 시는 상부 평균온도가 하부보다 0.2oC 높았다. 전기발 열체와 경유온풍난방기의 비교 시험에서는 난방 시 온실 상부와 하부의 온도차가 전기발열체 온실이 0.1~0.2oC로 경유온풍난방기 온실의 0.5~0.6oC보다 작았으며, 온실 상류와 하류의 온도차는 전기발열체 온실이 0~0.1oC로 경 유온풍난방기 온실의 1.3~1.4oC보다 작아 정밀한 온도관리가 가능하였다. 난방기간 동안 사용한 에너지사용량은 경유온풍난방기 온실이 경유 867L를, 전기발열체 온실이 전력량 8,959kWh를 사용하였으며, 난방비용은 각각 607 천원과 403천원이 소요되어 전기발열체 온실에서 약 34%의 비용절감 효과가 있었다. 전기발열체 온실의 경우 상대적으로 군락 상하부의 환경관리가 균일하여 초장을 비롯한 전반적 생육상황이 경유온풍난방기 온실보다 좋았으나 통계적으로 유의한 차이는 없었으며, 수확량 역시 전기발열체 온실의 작물군락 하부 온도가 경유온풍 난방기 온실보다 1.3oC 더 높게 관리되어 4.3% 증수효과가 있었으나 통계적으로 유의한 차이는 없었다. 원예 시설의 최적 난방 관리를 위해서는 각 난방기의 열전달 특성에 기초하여 난방기 용량, 배치, 열분배 방법에 대한 설계가 요구되며, 전열선 형태의 난방기 역시 작물형상 및 재배방법을 고려하여 전열선의 개수, 위치, 방열 온도 등에 대한 설계가 필요한 것으로 판단되었다.

Recently, the outboard engine system of internal combustion engine is widely used in the field of small ship propulsion. However, the internal combustion engine has serious problems of energy depletion and environmental problems, so electric propulsion methods are being studied. In this paper, we have developed important motors and controllers of electric propulsion system for small marine outboard motors. The motor design was performed through the motor characteristics analysis method, and the 30Kw system was developed through the BEMF processing circuit and the power conversion circuit by the embedded microprocessor. This study was carried out through government supported projects and achieved quantitative targets through accredited institutions.

본 연구는 희곡(戱曲) 장르인 심택추자희에서 주목하는 포공의 형상화에 초점을 맞추고자 했다. 또한 극장 예술로 변용된 심택추자희를 바탕으로 하여, 한국 창극의 대표적인 작품과 비교하여, 극화된 대본과 공연의 유사성과 차이점을 논구하는데에 역점을 두고자 했다. 대본의 측면에서 흥보전은 민담의 대립과 반복적 모티프를 활용하여 상관관계를 설정하고 있다. 또한 기본적으로 장면은 제시부, 상황부, 종결부로 구성되어 있다. 흥보전 은 형재애를 주제로 삼기 있기는 하지만 놀부(악형)를 중심으로 전개하는 특징을 지닌다. 반면에 포공출세는 신화 속 영웅의 모험 구조를 따르고 있다. 장면 구성은 흥보전의 경우처럼 세 부분 으로 분화되고 이중 상황부는 고난과 관련된 사건을 병렬적으로 열거하고 있다. 포공출세는 포공을 중심으로 선과 악의 구도를 가족관계를 다루고 있다. 무대미술의 측면에서 포공 출세의 무대는 그림, 병풍 등을 제한적으로만 사용하여 평면적인 인상에서 벗어나지 못하는 반면, 흥보전의 무대는 실제적 설계를 바탕으로 무대를 축조해서 입체적인 느낌을 자아내고자 했다. 한편 포공출세의 무대 (소)도구는 간략한 편이며 과학기술의 활용 역시 미미하다. 반면, 흥보전 의 무대(미술)는 대형화하여 과학적인 기술로 극적 효과를 극대화하려는 움직임을 지향하고 있다. 또한 음악은 포공출세와 흥보전 공연에서 높은 비중을 차지하 는 공연 요소이다. 비록 사용되는 악기가 상당한 차이를 보이지만 전반적으로 현악기와 타악기로 나뉜다는 점에서는 공통점을 공유하고 있다. 배우가 노래를 할 때 반주하는 점 역시 동일하지만, 포공출세의 경우에는 배우가 등장하기 전에 타악기로 무장(武場) 반주하고, 흥보전 의 경우에는 배우가 등장한 이후 배우의 동작에 맞춰 수성 반주한다.

Citrus fruit is important source of flavonoids, mainly flavanones which are narirutin and hesperidin. Those citrus flavonoids have been found to have health-related properties including antioxidant, anticancer, and anti-inflammatory. The main purpose of this study was to verify that the extraction of narirutin and hesperidin from Citrus peel can be more effective by combining pulsed electric field (PEF) pre-treatment and subcritical water extraction (SWE). Citrus unshiu peels were treated with PEF under conditions of electric field strength (3 kV/cm) and times (1 and 2 min). Subsequent SWE was conducted by using a Dionex Accelerated Solvent Extractor (ASE, Model 350) at extraction temperature 170°C for 10 min. The total flavonoids content was measured by using the aluminum chloride colorimetric method and the antioxidant capacity was analyzed by the Ferric reducing antioxidant power (FRAP) assay using spectrophotometer. The concentrations of narirutin and hesperidin were increased as PEF pre-treatment time increased. The highest concentrations of narirutin and hesperidin were 13.41 mg narirutin/g dry citrus peel and 141.16 mg hesperidin/g dry citrus peel at PEF pre-treatment condition of 3 kV/cm and 2 min. The total flavonoids contents of the extracts increased 105.2% and 123.1% for citrus peel PEF treated at 1 and 2 min, respectively. In addition, compared to the untreated sample, PEF pre-treatments of 1 and 2 min increased the antioxidant capacity of the extracts 109.2% and 160.8%, respectively. Therefore, the results demonstrate the potential of PEF pre-treatment to improve the SWE of flavonoids from citrus unshiu peel.

The effects of pulsed electric field (PEF) treatments on tenderization of beef were investigated. The beef was prepared by using the eye of round. PEF treatment of beef was performed using a newly manufactured movable batch chamber. The PEF treatment was conducted with electric field strength of 0.5~2.0 kV/cm using a fixed pulse width of 30 μs and frequency of 20 Hz. There was no significant change in appearance of PEF treated beef. The cutting force [N] of the sample was greatly reduced as the field strength of the PEF was stronger. The cutting force of beef treated with PEF at 2.0 kV / cm was 41.18 ± 3.28 N and the control was 57.25 ± 4.16 N. In the texture profile analysis, hardness and chewiness weakened as the field strength increased (p <0.05). There was no difference in springiness, cohesiveness, resilience before and after PEF treatment (p <0.05).

Polymer electrolyte membrane (PEM) is one of key elements to determine both electrochemical performances and lifetimes of fuel cell electric vehicles (FCEVs). PEM is exposed to a variety of dynamic stimuli (e.g., temperature, humidity, pressure, fuel gases and so on) under their operation conditions and meets unavoidable mechanical damages derived from unequal pressure difference between anode and cathode feed gases. Even though there have been approaches to evaluate the mechanical strength of PEM materials, most of the trials could provide static information on their mechanical strength. In this study, a pressure-loaded blister hybrid system connected with gas chromatography was developed to disclose the efficacy of the system as an evaluation tool of dynamic PEM strength under realistic FCEV operation conditions.

Microstructure, electric, and thermal properties of the Ta-Cu composite is evaluated for the application in electric contact materials. This material has the potential to be used in a medium for a high current range of current conditions, replacing Ag-MO, W, and WC containing materials. The optimized SPS process conditions are a temperature of 900oC for a 5 min holding time under a 30 MPa mechanical pressure. Comparative research is carried out for the calculated and actual values of the thermal and electric properties. The range of actual thermal and electric properties of the Ta-Cu composite are 50~300W/mk and 10~90 %IACS, respectively, according to the compositional change of the 90 to 10 wt% Ta-Cu system. The results related to the electric contact properties, suggest that less than 50 wt% of Ta compositions are possible in applications of electric contact materials.

서론 : 본 논문은 수동휠체어와 전동휠체어를 지원하는 제도에 관해 국내와 국외를 분석하고, 한국⋅미국⋅일본의 제도를 비교하여 한국에서 이동성 보장구 지급을 위한 제도적 발전방향을 제시하는데 목적이 있다. 본론 : 한국⋅미국⋅일본 세 개 국가의 이동성 보장구 지원정책에 대해 분석하고, 각 나라별로 지급하는 이동성보장구의 종류와 지원서비스에 관하여 고찰하였다. 분석 결과 미국과 일본에서는 수동 및 전동휠체어를 기능별로 세분화시켜 장애인의 기능에 적합한 보조기기를 제공하고 있다. 또한 보조기기를 제공하는 전담기관을 설치하여 휠체어지급에 필요한 서 비스뿐만 아니라 치료와 훈련과 같은 종합적인 서비스를 제공하고 있다. 마지막으로 휠체어 지급 시 전문가의 의견을 토대로 적합한 휠체어를 제공하고 있다. 결론 : 우리나라 역시 장애인들에게 적합한 보조기기를 지급하기 위해 지급되는 수동 및 전동휠체어의 종류를 세분화 할 필요가 있고, 다양한 서비스를 제공하기 위한 제도적 개선이 필요하다. 본 연구가 보조기기 지급제도의 개선에 도움이 되기를 바란다.

Many studies for personal mobility are increasing at the latest. One part of personal mobility study is electric scooter. Driving elements of electric scooter are battery and motor, patterns of vehicle being proposed multiply by manufacturer. The old and the infirm's population in domestic and abroad increases day by day. Thus, the personal vehicle for them that can be managed easily is needed for them. Following the trend “personal mobility”, this study propose electric-drive scooter which is portable and compact. Prototypes of proposed models are manufactured to commercialize it. As results, adopt of foldable type at electric scooter can be decreased size. Also 4-wheel scooter is more stable than 3-wheel sooter.

To obtain in vivo matured oocytes for dog cloning, serum progesterone (P4) level were employed for ovulate determination. Radioactive immunoassay (RIA) is a traditional serum hormone assay method with highly radioactivity. The aim of this study was to evaluate the reliability of RIA and to compare its canine serum P4 concentration determination accuracy to that of the electric chemiluminescence immunoassay (ECLI). To obtain in vivo matured oocytes for canine somatic cell nuclear transfer, serum P4 levels were accurately measured with both methods of RIA and ECLI. Although both methods detected similar P4 level before ovulation, the mean P4 concentration using ECLI was significantly higher than that using RIA from 3days before ovulation. Following ovulation, oocytes were collected by surgery, and a lower percentage of mature oocytes were observed using ECLI (39%) as compared to RIA (67%) if 4-8ng/ml of P4 were criteria for determination of ovulation. On other hand, high percentage of mature oocytes was observed using ECLI when 6–15 ng/mL of progesterone was criteria for ovulation determination. To determine whether in vivo oocytes obtained by ECLI method could be used for canine cloning, six canines were selected as oocyte donors and two puppies were produced after SCNT and embryo transfer. In conclusion, compared to the traditional RIA method, the ECLI method is a safe and reliable method for canine cloning.

Activated carbons (ACs) have been used as electrode materials of electric double-layer capacitors (EDLC) due to their high specific surface areas (SSA), stability, and ecological advantages. In order to make high-energy-density ACs for EDLC, petroleum pitch (PP) precarbonized at 500–1000°C in N2 gas for 1 h was used as the electrode material of the EDLC after KOH activation. As the pre-carbonization temperature increased, the SSA, pore volume and gravimetric capacitance tended to decrease, but the crystallinity and electrode density tended to increase, showing a maximum volumetric capacitance at a medium carbonization temperature. Therefore, it was possible to control the crystalline structure, SSA, and pore structure of AC by changing the pre-carbonization temperature. Because the electrode density increased with increasing of the pre-carbonization temperature, the highest volumetric capacitance of 28.4 F/cc was obtained from the PP pre-carbonized at 700°C, exhibiting a value over 150% of that of a commercial AC (MSP-20) for EDLC. Electrochemical activation was observed from the electrodes of PP as they were pre-carbonized at high temperatures above 700°C and then activated by KOH. This process was found to have a significant effect on the specific capacitance and it was demonstrated that the higher charging voltage of EDLC was, the greater the electrochemical activation effect was.

Ocean economy plays a crucial role in the strengthening maritime safety industry and in the welfare of human beings. Electric Submersible Pumps (ESP) have been widely used in floating platforms on the sea to provide oil for machines. However, the ESP fault may lead to ocean environment pollution, on the other hand, a timely fault diagnosis of ESP can improve the ocean economy. In order to meet the strict regulations of the ocean economy and environmental protection, the fault diagnosis of ESP system has become more and more popular in many countries. The vibration mechanical models of typical faults have been able to successfully diagnose the faults of ESP. And different types of sensors are used to monitor the vibration signal for the signal analysis and fault diagnosis in the ESP system. Meanwhile, physical sensors would increase the fault diagnosis challenge. Nowadays, the method of neural network for the fault diagnosis of ESP has been applied widely, which can diagnose the fault of an electric pump accurately based on the large database. To reduce the number of sensors and to avoid the large database, in this paper, algorithms are designed based on feature extraction to diagnose the fault of the ESP system. Simulation results show that the algorithms can achieve the prospective objectives superbly.