• 전기학회논문지P
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• 제61권3호
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• pp.134-139
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• 2012

The power characteristics of the Mg-Air fuel cell were investigated with regard to variation of load conditions. The types of load current using for the Mg-Air fuel cell with 10% NaCl electrolyte were step type, ramp type and pulse type. It was found that transient phenomena occurred in the step current load, which is due to activate of the oxidation-reduction reaction process. And the transient time increase with the load current increase. In the load current of ramp type, the slop of voltage drop increased with current load slop ${\alpha}$ increase. The load voltage and power decreased according to the pulse period of load current decrease were attributed to the metal sludges.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2016년도 춘계학술대회
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• pp.302-304
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• 2016

The purpose of this paper is to draw comparison between the performance of ${\alpha}-{\beta}-{\gamma}$ filter and Kalman filter of a tracking module for ARPA system on board high dynamic warship. The comparison is based on the filters' capability to reduce residual error and maintain a stable transient response. The residual error is computed from the difference between the observed the predicted positions for the entire tracking period. The results indicate that the Kalman filter has a higher tracking accuracy compared to the optimal ${\alpha}-{\beta}-{\gamma}$ filter. However, both filters have a similar transient response.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.104-106
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• 2000

Transient Stability of a power systems is its ability to maintain synchronous operation of machine when subjected to a large disturbance. This paper presents a new methodology for speed-up transient stability evaluation in SIME. SIME is a hybrid direct method including time simulation to enhance flexibility. The First features of the proposed method are that generator grouping can be performed even in very stable cases and that the stability of a contingency can be evaluated from a short period of time simulation results. The second features of the proposed method are that using power-angle trajectory and subdividing contingency classification have improved the screening capability.

• 한국항해항만학회지
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• 제28권5호
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• pp.353-358
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• 2004

ISSC 스팩트럼을 기초로 종래의 불규칙파가 아닌 새로울 과도 불규칙파를 설계하였다. 이 설계불규칙파를 장수조에서 조파기를 사용하여 발생시키고, 파고계와 6자유도계를 설치하여서 모형선의 횡동요 운동을 계측하였다. 모형선의 최대 횡동요각의 실험값과 이론값을 비교하여 단기 해상에서 발생 가능한 횡동요 피크치를 추정하는 방법에 관하여 검토하였다.

• Biomolecules & Therapeutics
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• 제7권3호
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• pp.234-241
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• 1999

The present study assessed the cerebroprotective effect of platelet-activating factor(PAF) antagonists in transient cerebral ischemia of rats. Right middle cerebral artery (MCA) of Sprague-Dawley rats was occluded for 2 hours using an intraluminal filament technique, and was reperfused for 6 hours following cerebral ischemia. The infarct area of seven coronal brain slices was measured morphometrically following stain ing in the 2% 2,3,5-triphenyltetrazolium chloride solution. The changes in regional cerebral blood flow (rCBF) and pial arteriolar diameter were measured by laser-Doppler flowmetry and by a videomicroscopy, respectively. The infarct size was significantly reduced by PAF antagonists, BN 52021 and CV-6209, which were administered i.p. 10 min before MCA occlusion. Pretreatment with PAF antagonists significantly restored the changes in pial arterial diameter as well as those in rCBF during the period of cerebral ischemia-reperfusion. PAF antagonists significantly inhibited the inducible nitric oxide synthase activity in the pial arteries ipsilateral to ischemia. These results suggest that PAF antagonists exert a cerebroprotective effect against ischemic brain damage through an improvement of postocclusive cerebral blood flow.

• 천문학회보
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• 제44권1호
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• pp.43.1-43.1
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• 2019

We perform the Lomb-Scargle Periodogram analysis to protostars identified by the JCMT Transient Survey, which monitors 8 nearby star forming regions. The observations have been done monthly for over 3 years using SCUBA-2 (the Submillimetre Common User Bolometer Array 2) in two wavelengths, 450 and $850{\mu}m$. Under the threshold of 1% False Alarm Probability, we found 16 variable sources including EC53, which is the first variable protostar detected by the JCMT Transient Survey. Most of the variable sources are cataloged as protostars (classified via the Spitzer data, Megeath et al. 2012; Dunham et al. 2015), but SerpS-MM19, which has a clear 1-year period, is a candidate of a first hydrostatic core (Maury et al. 2011; Young et al. 2018).

• 대한전기학회논문지:시스템및제어부문D
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• 제52권10호
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• pp.611-617
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• 2003

A mechanical or electrical stimulation to the mandibular symphysis during a maximal voluntary clenching of the teeth always produces a jaw jerk followed by a silent period (transient stops) in the masseteric EMG (electromyogram). Generally, a mechanical stimulation is followed by a single silent period, and an electrical stimulation is followed by multiple silent periods. In this paper, we propose a new algorithm for determining the duration of the masseter silent period. The decision approach in essentially based upon a segmentation algorithm consisted of variance filter, median filter and gaussian filter. The new adaptive digital notch filter using R-CLMS(reverse constrained least mean-squared) algorithm is proposed for the elimination of powerline(60Hz) noise. At the same time, we design a real time measurement system for the EMG silent period under Window base.

• 한국소음진동공학회논문집
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• 제14권5호
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• pp.424-431
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• 2004

An implicit direct-time integration method for obtaining transient responses of general dynamic systems is described. The conventional Newmark method cannot be directly applied to state-space first-order differential equations, which contain no explicit acceleration terms. The method proposed here is the state-space Newmark method that incorporates the average velocity concept, and can be applied to an analysis of general dynamic systems that are expressed by state-space first-order differential equations. It is also readily coded into a program. Stability and accuracy analyses indicate that the method is numerically unconditionally stable like the conventional Newmark method, and has a period error of 2nd-order accuracy for small damping and 4th-order for large damping and an amplitude error of 2nd-order, regardless of damping. In addition, its utility and validity are confirmed by two application examples. The results suggest that the proposed state-space Newmark method based on average velocity be generally applied to the analysis of transient responses of general dynamic systems with a high degree of reliability with respect to stability and accuracy.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.545-553
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• 2016

The failure probabilities of the reactor pressure vessel (RPV) for low temperature over-pressurization (LTOP) and cool-down transients are calculated in this study. For the cool-down transient, a pressure-temperature limit curve is generated in accordance with Section XI, Appendix G of the American Society of Mechanical Engineers (ASME) code, from which safety margin factors are deliberately removed for the probabilistic fracture mechanics analysis. Then, sensitivity analyses are conducted to understand the effects of some input parameters. For the LTOP transient, the failure of the RPV mostly occurs during the period of the abrupt pressure rise. For the cool-down transient, the decrease of the fracture toughness with temperature and time plays a main role in RPV failure at the end of the cool-down process. As expected, the failure probability increases with increasing fluence, Cu and Ni contents, and initial reference temperature-nil ductility transition ($RT_{NDT}$). The effect of warm prestressing on the vessel failure probability for LTOP is not significant because most of the failures happen before the stress intensity factor reaches the peak value while its effect reduces the failure probability by more than one order of magnitude for the cool-down transient.

• 한국동물학회지
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• 제29권2호
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• pp.107-120
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• 1986

한냉환경에 Sprague-Dawley계 웅성흰쥐를 순화시켜 SLDH, SLDH 동위효소, SALP, SALP 동위효소 및 SCPK 등의 활성치의 보상 변화에 따른 변화를 관찰 검토하였다. 한냉순화는 $4\\pm1^\\circC$(상대습도 70$\\sim$80%)에서 안정상태로 36일간 순화처리 하였으며 SLDH의 활성치는 한냉순화 초기에 유의성 있게 증가하였으나 곧 감소되어 정상치로 접근하며 36일구 까지 항정상태를 지속하였으며, 대조군의 SLDH 동위효소는 주로 3개의 전기영동분획 즉 $LDH_1, LDH_2, LDH_4 및 LDH_5$를 나타냈으나 한냉순화 기간중에는 3개의 분획 즉 $LDH_1, LDH_2 및 LDH_3$가 나타났으며, 한냉순화 시의 SLDH의 상승은 $SLDH_1, SLDH_2 및 SLDH_3$의 반영이라고 생각되며 SALP의 활성치는 한냉순화 초기에 유의적으로 증가하였으나 곧 감소되어 정상치로 접근하여 36일구까지 항정상태를 지속하였고, 대조군의 SALP동위효소는 2개의 전기영동분획을 지속하고 있으며, 한냉순화군 초기의 SALP 활성치의 증가는 $SALP_1$ 분획의 즉각적인 증가의 반영임을 알 수 있고, 한냉순화로 인하여 SCPK의 활성치는 순화초기에 유의적으로 상승하였으나 곧이어 안정치로 접근하여 순화 말기까지 항정상태를 지속하였다. 한냉순화$(4\\pm1^\\circC)$처리는 한냉 초기에 SLDH, SLDH 동위효소, SALP, SALP 동위효소 및 SCPK 활성치 모두에 영향을 끼치는 것으로 생각되며 따라서 상기 각종 효소가 직접 또는 간접적으로 열적조절에 관여하는 것으로 생각된다.