• Journal of Electrical Engineering and Technology
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• 제6권5호
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• pp.613-617
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• 2011

In the present paper, a new type of electrical actuator, an electromagnetic force driving actuator (EMFA), applicable to air circuit breaker is developed and analyzed. Transient analysis is performed to obtain the dynamic characteristics of EMFA. The distribution of static magnetic flux is obtained using the finite element method. The coupled problems of electrics and mechanics governing equations are solved using the time-difference method. According to the interception rate of each contactor, investigation of the contactor spring load condition is conducted and applied to the threelink system. Comparisons of the dynamic characteristics of the three-link simulation and experimental data are performed.

• Fisheries and Aquatic Sciences
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• 제12권4호
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• pp.331-338
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• 2009

This study presents physiological rates of respiration and excretion, clearance rate, and assimilation efficiency of the ark shell Scapharca broughtonii, determined during 2007 from specimens collected in Gamak Bay on the south coast of Korea. Physiological parameters were measured monthly under static, laboratory controlled conditions with ambient conditions, and measurements were performed seasonally in order to estimate scope for growth and its probable sources of variation. Temperature directly influenced respiration and excretion. Clearance rates showed a tendency to be low during May-August, which is a period of gametogenesis. Assimilation efficiency was not significantly different seasonally and was independent of the concentration of chlorophyll a. The scope for growth was negative during high-temperature months (July-August), reflecting the high temperature and low clearance rate, and had its highest positive values during spring and autumn. The energy budget or growth potential of bivalves has been applied to other economically important species. Data on the physiological parameters and scope for growth of S. broughtonii obtained in this study will be used to assess the carrying capacity for ark shell cultivation.

• 드라이브 ㆍ 컨트롤
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• 제19권3호
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• pp.39-46
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• 2022

In South Korea, to evaluate the rollover safety of domestic vehicles, the maximum slope angle of the vehicle is specified, which is verified by the rollover safety test of driving vehicles. However, the domestic rollover safety test is not suitable for buses, because the small amount of static stability factor (SSF) will invalidate the rollover experimental equation due to the high center of mass position of buses. To solve the above problems, a dynamic model of the bus is prepared with assumptions of mass and suspension spring properties. Subsequently, the maximum slope angle of the model was computed by using the simulation of multi-body dynamics, and the result was compared with actual test results to validate the dynamics model. Also, the rollover Fishhook (roll stability) test was conducted in the simulation for driving model. During the simulation, roll angle and roll rate were calculated to check if a rollover occurred. Through the rollover simulation of buses, the domestically regulated formula for rollover safety and the procedure of rollover test for driving vehicles are evaluated. The conclusion is that the present regulation of rollover test should be reconsidered for buses to ensure to get the valid results for rollover safety.

• 한국패류학회지
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• 제27권3호
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• pp.205-211
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• 2011

This study presents physiological rates of oxygen consumption, ammonia excretion, feeding rates, O/N ratio and assimilation efficiency of the blood cockle, Scapharca subcrenata, determined from specimens collected in Yeoja bay on the south coast of Korea. Physiological parameters were measured monthly under static, laboratory controlled conditions with ambient conditions, and measurements were performed seasonally in order to estimate scope for growth and its probable sources of variation. Oxygen consumption and ammonia excretion rates have been increased as temperature increased with the highest value of August, 2008. Feeding rate was the highest during April whereas the lowest was during August which is a period of gametogenesis with minimum biomass of phytoplankton around sampling area. Assimilation efficiency was not significantly different seasonally and O/N ratio decreased during July to August. The scope for growth was negative during high temperature months(July to August), reflecting the high temperature and low feeding rate, and had its highest positive values during spring and autumn. Data on the physiological parameters and scope for growth of Scapharca subcrenata obtained in this study will be used to assess the carrying capacity for blood cockle cultivation.

• 한국환경생태학회지
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• 제32권3호
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• pp.274-288
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• 2018

낙동강 유역에 조성된 신규습지에서 서식환경에 대한 어류의 분포 특성을 평가하고, 이를 기반으로 한 관리방안 도출을 위해 42개 습지에서 환경요인의 측정과 어류 조사를 시행하였다. 조사 기간 동안 총 30종의 어류가 출현하였으며, 이 중에서 배스(Micropterus salmoides)와 블루길(Lepomis macrochirus)과 같은 외래어종의 비율이 상대적으로 높았다. 특히, 밀어(Rhinogobius brunneus)나 끄리(Opsariichthys uncirostris amurensis), 피라미(Zacco platypus) 등의 어류는 흐름이 있는 환경을 선호하기 때문에 배스가 우점하는 습지(정체수역)에서 상대적으로 낮은 밀도를 가지는 것으로 사료된다. SOM (Self-Organizing Map)을 활용한 패턴분석 결과, 각 습지의 서식환경 특성에 따라 어류 종의 출현빈도가 상이한 것으로 분석되었다. 어류 종의 분포는 각 습지의 수심 변화와 수생식물 피도에 민감하게 영향 받는 것으로 나타났으며, 수온이나 pH, 용존산소 등의 이화학적 요인 변화에 대한 영향은 적었다. 특히 수생식물의 피도는 어류의 종다양성이나 밀도에 강한 영향을 주는 것으로 분석되었으며, 수변식생이 부족한 습지에서는 어류가 적은 풍부도와 다양성을 가지는 것으로 나타났다. 본 연구 결과를 기반으로 평가할 때 어류 등의 생물다양성 증진을 위해 호안사면의 높은 인공성이나 수변식생의 부족한 습지 등은 개선이 필요할 것으로 사료되며, 건강성 확보를 위한 지속가능한 관리방안이 마련되어야 할 것으로 판단된다.