• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.169-174
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• 1998

An 1200-day time-dependent fuel-management for the transition from 37-element fuel to CANFLEX-NU fuel in a CANDU 6 reactor has been simulated to show the compatibility of the CANFLEX-NU fuel with the reactor operation. The simulation calculation were carried out with the RFSP code, provided by cell averaged hel properties obtained from the POWDERPUFS-V code. The refueling scheme for both fuels was an eight bundle shift art a time. The simulation results show that the maximum channel and bundle powers were maintained below the licence limit of the CANDU 6. This indicates that the CANFLEX-NU fuel bundle is compatible with the CANDU 6 reactor operation during the transition period.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1249-1255
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• 2007

We have investigated the photophysical properties of dansyl-N-methylaminobenzoic acid (DABAH) as a ligand and its lanthanide (Ln3+)-cored complexes (Ln3+-(DABA)3(terpy)) in order to determine the main energy transfer pathway for sensitized near infrared emission of Ln3+ ions (Ln3+ = Nd3+ and Er3+) in Ln3+- (DABA)3(terpy). The fluorescence spectrum of DABAH shows a large Stokes shift with increasing solvent polarity. This large Stokes shift might be due to the formation of a twisted intramolecular charge transfer (TICT) state, as demonstrated by the large dipole moment in the excited state. It is in good agreement with the result that the phosphorescence even in the Gd3+-cored complex based on the DABAH ligand was not observed, maybe due to the highly forbidden character of the S1 → T1 transition in the DABAH ligand. A short decay component (ca. 1 ns) was observed in Er3+-(DABA)3(terpy) whereas the fluorescence lifetimes of DABAH and its Gd3+-(DABA)3(terpy) are observed about ~10 ns. The short component could be originated from the energy transfer process between the ligand and the Ln3+ ion. Based on the fluorescence of DABAH its Ln3+- (DABA)3(terpy), the sensitization of Ln3+ luminescence in the Ln3+-(DABA)3(terpy) takes place by the energy transfer via the TICT state of DABAH in the excited singlet state rather than via the excited triplet state.

• 한국자동차공학회논문집
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• 제7권6호
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• pp.182-197
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• 1999

Described in this paper is an optimal driving control algorithm which focused on the improvement of fuel economy and the minimization of pollutant emissions in the parallel type hybrid drivertrain system for transit bus. For the energy balance among components such as engine, induction machine and buttery, the algorithm for power split ration determine is proposed. When it is implemented in the hybrid electric control unit(HECU) , using the sub-optimal method and the approximate technique , it is possible to save the memory , to shorten the calculation time, and to achieve the efficient driving actually. A Shift strategy for automated manual transmission is the other side of the driving control algorithm. It enables to select the optimal gear by using several shift maps which were predefined from the proposed method in this paper, As a results of driving simulation, it is proved that these algorithms make the hybrid drivetrain system to reduce fuel consumption and emissions considerably and to have the ability to the efficient use of battery.

• 한국발생생물학회지:발생과생식
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• 제16권1호
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• pp.53-58
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• 2012

Circadian rhythmicity (e.g. secretory pattern of hormones) plays an important role in the control of reproductive function. We hypothesized that the alteration of feeding pattern via meal time shift/restriction might disrupt circadian rhythms in energy balance, and induce changes in reproductive activities. To test this hypothesis, we employed simple animal model that not allowing $ad$ $libitum$ feeding but daytime only feeding. The animals of $ad$ $libitum$ feeding group (Control) have free access to food for 4 weeks. The day feeding (=reverse feeding, RF) animals (RF group) have restricted access to food during daytime (0900-1800) for 4 weeks. After completing the feeding schedules, body weights, testis and epididymis weights of animals from both group were not significantly different. However, the weights of seminal vesicle (control : RF group = $0.233{\pm}0.014g$ : $0.188{\pm}0.009g$, $p$<0.01) and prostate (control : RF group = $0.358{\pm}0.015g$ : $0.259{\pm}0.015g$, $p$<0.001) were significantly lower in RF group animals. The mRNA levels of pituitary common alpha subunit ($C{\alpha}$; control : RF group = $1.0{\pm}0.0699$ AU : $0.1923{\pm}0.0270$ AU, $p$<0.001) and $FSH{\beta}$ (control : RF group = $1.0{\pm}0.1489$ AU : $0.5237{\pm}0.1088$ AU, $p$<0.05) were significantly decreased in RF group. The mRNA levels of ACTH were not significantly different. We were unable to find any prominent difference in the microstructures of epididymis, and there were slight alterations in those of seminal vesicles after 4 weeks of reversed feeding when compared to control samples. The present study demonstrates that the shift and/or restriction of feeding time could alter the pituitary gonadotropin expression and the weights of seminal vesicle and prostate in rats. These data suggest the lowered gonadotropin inputs may decrease androgen secretion form testis, and consequently results in poor response of androgen-dependent tissues such as seminal vesicle and prostate.

• 청정기술
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• 제29권1호
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• pp.39-45
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• 2023

To investigate the effects of Mg addition at different aging times and temperatures, Cu/MgO/Al₂O₃ catalysts were synthesized for the low-temperature water gas shift (LT-WGS) reaction. The co-precipitation method was employed to prepare the catalysts with a fixed Cu amount of 30 mol% and varied amounts of Mg/Al. Synthesized catalysts were characterized using XRD, BET, and H₂-TPR analysis. Among the prepared catalysts, the highest CO conversion was achieved by the Cu/MgO/Al₂O₃ catalyst (30/40/30 mol%) with a 60 ℃ aging temperature and a 24 h aging time under a CO₂-rich feed gas. Due to it having the lowest reduction temperature and a good dispersion of CuO, the catalyst exhibited around 65% CO conversion with a gas hourly space velocity (GHSV) of 14,089 h-1 at 300 ℃. However, it has been noted that aging temperatures greater or less than 60 ℃ and aging times longer than 24 h had an adverse impact, resulting in a lower surface area and a higher reduction temperature bulk-CuO phase, leading to lower catalytic activity. The main findings of this study confirmed that one of the main factors determining catalytic activity is the ease of reducibility in the absence of bulk-like CuO species. Finally, the long-term test revealed that the catalytic activity and stability remained constant under a high concentration of CO₂ in the feed gas for 19 h with an average CO conversion of 61.83%.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2660-2666
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• 2020

Korea successfully achieved energy independence in the shortest period of time from being the poorest country in terms of energy 50 years ago through steady development of nuclear technology. In the past, the nuclear industry has been driven through government-centered policy development, public institution-based research, and industrial facility and infrastructure construction. Consequently, South Korea became a nuclear energy powerhouse exporting nuclear power plants to the UAE, surpassing the level of domestic technological independence. However, in recent years, the nuclear industry in Korea has experienced a decline in new plant construction since the Fukushima accident in Japan, which caused changes in public perspectives regarding nuclear power plant operation, more stringent safety standards on the operation of nuclear power plants, and a shift in governmental energy policy. These changes are expected to change the domestic nuclear industry ecosystem. Therefore, in this study, we investigate the priority of technology development investment from the perspective of experts in private nuclear power companies, shifting the focus from government-led nuclear R&D policies. To establish a direction in nuclear technology development, a survey was conducted by applying an analytic hierarchy analysis to experts who have worked in nuclear power plants for more than 15 years. The analysis items of focus were the 3 attributes of strategic importance, urgency, and business feasibility of four major fields related to nuclear energy: nuclear safety, decommissioning, radioactive waste management, and strengthening industrial competitiveness.

• The Journal of the Acoustical Society of Korea
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• 제22권3E호
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• pp.133-140
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• 2003

A time series simulation is presented by a ray approach for the simulating the received waveform of a broadband acoustical signals interacting with the ocean boundaries. The environment is assumed to be horizontally stratified, and the seafloor is described in terms of homogeneous fluid half-space. The ray approach includes the effects of reflection from the air-water, water-sediment interface and phase shifts due to boundaries interaction. To generate time series, we assume that the acoustic energy propagates from source to receiver along eigenrays and represent the action of the bottom on the incident wave by a linear filter and characterized in the frequency domain by the transfer function. As example application, the time series for an explosive source in a shallow water environment is calculated and analyzed in terms of acoustical process. good agreement with measured time series is demonstrated.

• 한국식품과학회지
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• 제27권2호
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• pp.193-198
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• 1995

여러 저장온도($5{\sim}25^{\circ}C$)에서 저장하는 동안의 두부의 물성 변화는 응력완화현상을 이용하여 시간-온도 중첩 이론을 통해 계산하고 분석하였으며 WLF(Williams-Landel-Ferry)식을 이용해서 품질변화를 예측할 수 있는 적용식을 제시하였다. 저장온도가 낮을수록 저장시 두부 조직의 초기응력 및 평형응력(equilibrium stress)이 강하게 나타났고, $15^{\circ}C$ 온도를 기준으로 이동인자를 이용하여 좌우 수평으로 이동시 하나의 중첩곡선(master curve)을 구하였다. 이동인자와 중첩곡선을 이용하여 WLF식에 적용해서 활성화 에너지를 계산하였고 임의 온도에서 저장 시간을 예측하였으며, 실제 두부 조직의 저장성을 논하였다.

• Transactions on Electrical and Electronic Materials
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• 제9권2호
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• pp.52-56
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• 2008

Carbon nanotube films were fabricated by the catalytic CVD method. Plasma processed time effects on the field emission property were studied. The atomic structure was observed by using X-ray photoelectron spectroscopy (XPS). The surface composition changes were observed on the plasma processed CNT films. The O1s/C1s signal ratio and the Fls/Cls signal ratio changed from 1.1 % to 24.65 % and from 0 % to 3.1 % with plasma process time, respectively. We could guess it from these results that the Ar plasma process could change the surface composition effectively. In the case of the original-CNT film, no carbon shift was observed. In the case of the Ar plasma processed CNT films, however the oxygen related carbon shifts were observed. This oxygen related carbon shift at higher binding energy implies the increment of amount of the oxygen. It's possible that the increment of these bonds between carbon and oxygen results in the improvement of field emission performance.

• 전기학회논문지
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• 제67권9호
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• pp.1152-1158
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• 2018

In this paper, Optimal operation plan through load analysis of industrial end-user is suggested. It calculated economic feasibility of ESS with detailed power lad analysis and conditions. Generally, if the latest maximum power is less than 30% of contracted power, it can not be peak shaving operation plan. and if the peak load level stays stead for 24 hours, it is difficult peak shaving for ESS. In addition to, When the peak load is occurred in summer or winter, a hybrid operation method combining the peak shaving plan and the time shift method is proposed. Therefore, When ESS is installed in industrial electrical customer, it is achieved best effect through the optimal operation plan.