• 동력기계공학회지
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• 제21권1호
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• pp.5-10
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• 2017

Pitch drive system in wind turbine is composed by the planetary gear system to satisfied its required performance such as long life and light weight for gear train. When the planetary gear system can reduce its volume and weight, the power consumption of the wind turbine can be reduced. In this study, the planetary gear system of the pitch drive system in medium-sized wind turbine is obtained for weight reduction by shape optimization method. And the planetary gear system is verified for their strength by the structural analysis.

• KSBB Journal
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• 제13권3호
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• pp.289-294
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• 1998

The effects of various step-fortifications of the initial medium with amino acids, glucose, and vitamines on the growth and metabolism of a hybridoma cell line in batch cultures were quantified. Comparisons between the metabolic rates of the various cultivations were made for the exponential growth phase. Fortification of the basal medium resulted in higher cell densities through a prolonged growth phase, but the maximum specific growth rate was not affected. The uptake rate of glutamine increased with the addition of amino acids but did not change upon the addition of glucose or vitamines. The specific glucose consumption decreased slightly with the addition of amino acids but increased production of lactate and {{{{ { NH}`_{4 } ^{ +} }}}}. A reciprocal relationship between the yields of {{{{ { NH}`_{4 } ^{+ } }}}} and lactate indicated a joint regulation of glycolysis and glutaminolysis.

• Journal of Communications and Networks
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• 제18권5호
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• pp.857-869
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• 2016

This paper proposes an X-MAC/BEB protocol that runs a binary exponential backoff (BEB) algorithm on top of an X-MAC protocol to save more energy by reducing collision, especially in densely populated wireless sensor networks (WSNs). X-MAC, a lightweight asynchronous duty cycle medium access control (MAC) protocol, was introduced for spending less energy than its predecessor, B-MAC. One of X-MAC 's conspicuous technique is a mechanism to allow senders to promptly send their data when their receivers wake up. X-MAC, however, has no mechanism to deal with sudden traffic fluctuations that often occur whenever closely located nodes simultaneously diffuse their sense data. To precisely evaluate the impact of the BEB algorithm on X-MAC, this paper builds an analytical model of X-MAC/BEB that integrates the BEB model with the X-MAC model. The analytical and simulation results confirmed that X-MAC/BEB outperformed X-MAC in terms of throughput, delay, and energy consumption, especially in congested WSNs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.209-211
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• 2005

This paper proposes a adaptive medium-access control(MAC) protocol designed for low-power wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy savings.

• 대한화학회지
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• 제18권3호
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• pp.153-156
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• 1974

황산산성에서의 히드라진과 요오드의 반응에 대하여, 기체발생속도를 측정하였다. 이미 보고된 요오등의 소비속도의 경우와 마찬가지로, 히드라진 및 요오드의 농도에 관하여는 1차 반응이며, 반응속도는 요오드화이온의 농도에 역비례한다. 그뿐만 아니라, 요오드으이 소비속도롸 기체 발생속도가 거의 같으므로, 수명이 긴 중간물이 생기지 않는다고 결론지을 수 있다

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권2호
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• pp.115-118
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• 1998

Utilization of yeast extract and formation of byproduct metabolite were investigated for hyperthermophilic archaeon Sulfolobus solfataricus (DSH 1617). In both batch and fed-batch cultivations of S. solfataricus, maximal cell density, {{{{ { NH}`_{4 } ^{ +} }}} ion production and pH change were highly dependent on the ratio of yeast extract to glucose in the medium. Variation of {{{{ { NH}`_{4 } ^{ +} }}}} ion level was identified as a major cause of pH change during cultivation, and acidification of culture broth was attributed to consumption of {{{{ { NH}`_{4 } ^{ +} }}}} ions rather than formation of acid byproducts. It was also observed that increase of {{{{ { NH}`_{4 } ^{ +} }}}} ion concentrations in the medium resulted in greater degree of growth inhibition.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.24-26
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• 2004

For past decade, medium voltage circuit breakers have used the spring-driven mechanical system for interrupting of electric power. However, these mechanisms have many disadvantages of high power consumption, mechanical control components and electrical switching ones for the coil current. Recently, the vacuum interrupter operated by permanent magnet actuator gives outlook on improved characteristic, higher reliability and cost price reduction as well as the feature of simple structure and few components. This paper deals with the dynamic characteristics of permanent magnet actuator used in the medium voltage distribution systems. Coupled finite element method is used to analysis the dynamic characteristics of permanent magnetic actuator and we compared with those of conventional ones.

• 한국미생물·생명공학회지
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• 제18권4호
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• pp.406-410
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• 1990

토양에서 분리한 알칼리내성 Bacillus sp.의 자체 chromosomal DNA에서 유래된 strong promoter를 지닌 plasmid p-12B1을 공여균주에 삽입시키고 이 promoter의 활성을 최적화할 수 있는 배양조건을 검토하였다. 글루코오스가 고갈된 시점부터 세포의 활성은 유지되나 포자는 형성되지 않을 정도로 낮은 글루코오스 소비속도를 유지해 제한된 글루코오스를 연속적으로 공급해줌으로써 promoter의 활성을 최대로 높일 수 있었다. 또한 배지조성의 변화로 균체를 생육시킨 후 유전자 발현을 유도하는 것이 가능하였으며, 이 점에 대해서는 보다 구체적인 연구가 진행되어야 할 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.279-282
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• 2003

This paper proposes a medium-access control(MAC) protocol designed for wireless multi-hop sensor networks which is used for connecting physical world and cyber computing space. Wireless multi-hop sensor networks use battery-operated computing and sensing device. We expect sensor networks to be deployed in an ad hoc fashion, with nodes remaining inactive for long time, but becoming suddenly active when specific event is detected. These characteristics of multi-hop sensor networks and applications motivate a MAC that is different from traditional wireless MACs about power conservation scheme, such as IEEE 802.11. Proposed MAC uses a few techniques to reduce energy consumption. Result show that proposed MAC obtains more energy sayings.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.1040-1042
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• 2004

For past decade, medium voltage circuit breakers have used the spring-driven mechanical system for interrupting of electric power. However, these mechanisms have many disadvantages of high power consumption, mechanical control components and electrical switching ones for the coil current. Recently, the vacuum interrupter operated by permanent magnet actuator gives outlook on improved characteristic, higher reliability and cost price reduction as well as the feature of simple structure and few components. This paper deals with the dynamic characteristics of permanent magnet actuator used in the medium voltage distribution systems. Coupled finite element method is used to analysis the dynamic characteristics of permanent magnetic actuator and we compared with those of conventional ones