• Nuclear Engineering and Technology
• /
• 제56권3호
• /
• pp.907-915
• /
• 2024

Various core designs with multi-batch fuel management (FM) are proposed and optimized for an innovative small modular reactor (iSMR), focusing on enhancing the inherent safety and neutronic performance. To achieve soluble-boron-free (SBF) operation, cylindrical centrally-shielded burnable absorbers (CSBAs) are utilized, reducing the burnup reactivity swing in both two- and three-batch FMs. All 69 fuel assemblies (FAs) are loaded with 2-cylindrical CSBA. Furthermore, the neutron economy is improved by deploying a truly-optimized PWR (TOP) lattice with a smaller fuel radius, optimized for neutron moderation under the SBF condition. The fuel shuffling and CSBA loading patterns are proposed for both 2- and 3-batch FM with the aim to lower the core leakage and achieve favorable power profiles. Numerical results show that both FM configurations achieve a small reactivity swing of about 1000 pcm and the power distributions are within the design criteria. The average discharge burnup in the two-batch core is comparable to three-batch commercial PWR like APR-1400. The proposed checker-board CR pattern with extended fingers effectively assures cold shutdown in the two-batch FM scenario, while in the three-batch FM, three N-1 scenarios are failed. The whole evaluation process is conducted using Monte Carlo Serpent 2 code in conjunction with ENDF/B-VII.1 nuclear library.

• 한국통신학회논문지
• /
• 제23권5호
• /
• pp.1349-1359
• /
• 1998

본 논문에서는 디지털 FM 스테레오 합성 신호 발생기(FM stereo composite signal generator)의 구현 결과를 제시하였다. 직접 디지털 주파수 합성기(DDFS)를 응용하여 단일 칩으로 디지털화 하였으며, $1.0\mu\textrm{m}$ CMOS 게이트­어레이 기술로 구현하였다. 설계 결과는 시뮬레이션을 통해 신호 발생 과정을 검증하였고, 디지털 칩을 실장한 평가용 인쇄회로기판을 제작하여 신호 발생 값을 비교 분석하였다. 측정 결과 디지털-아날로그 변환기의 비트 수가 12비트일 때 신호 대 잡음비가 74dB가 측정되었으며, 이는 아날로그 회로보다 14dB 더 우수한 것이다. 범용 스테레오 입출력으로 16비트 디지털-아날로그 변환기를 사용할 경우 아날로그 방식보다 훨씬 우수한 스펙트럼 순수도를 얻을 수 있을 것으로 기대한다. 디지털 FM 스테레오 합성 신호 발생기는 신호 대 잡음비, 정확도, 튜닝 안정성,그리고 집적도측면에서 기존의 아날로그회로보다 우수한 특성을 보인다.

• BMB Reports
• /
• 제29권5호
• /
• pp.398-404
• /
• 1996

Light-chilling effects were investigated in chilling-sensitive cucumber (Cucumis sativus L. cv. Ilmichungjang) and chilling-resistant pea (Pisum sativum L. cv. Giant) leaf discs in relation to possible damage in D1 protein. In both plants, dark-chilling did not cause any noticeable changes in (Fv)m/Fm and lincomycin did not affect the decrease in (Fv)m/Fm caused by light-chilling. This result suggests that the de novo synthesis of D1 protein did not occur actively during light-chilling. In pea light-chilled for 6 h. the decreased (Fv)m/Fm was partly recovered in the dark, and almost complete recovery was observed in the light. In cucumber light-chilled for 3 h. the reduced (Fv)m/Fm decreased further for the initial 2 h recovery process in the light regardless of the treatment of lincomycin and recovered very slowly. In both plant species, the treatment of lincomycin inhibited the recovery process in the light, but did not significantly inhibit the process in the dark. In cucumber leaves pulse-labeled with $[^{35}S]Met$, the labeled band intensities of isolated pigment-protein complexes were almost the same during the 6 h light-chilling, but significant decreases in band intensities were observed during the 3 h recovery period. This result suggests that the irreversibly damaged D1 protein was degraded during the recovery period. However, no noticeable changes were observed in the pea leaves during the 12 h chilling and 3 h recovery period. The polyacrylamide gel electrophoresis of the pigment-protein complexes showed that the principal lesion sites of light-chilling were different from those of room temperature photoinhibition.

• 한국인쇄학회지
• /
• 제20권2호
• /
• pp.31-43
• /
• 2002

Screen printing is a stencil process whereby ink is transferred to the substrate through a stencil supported by a fine fabric mesh. Therefore screen had a tendency to distort and swell, as ink was deposited between the fibers, and were difficult to clean. The tow importance of stencil parameters that affect print quality are stencil thread diameter and the fabric thickness because of their influence on both ink deposit and print definition. Since screen printing inks can be formulated to adhere to almost any surface, and the printing process itself can be handled almost any substrate in a wide variety of shape, screen printing is a very versatile process. The small size pronting is reproduced image used screen printing because the surface of substrates is not suited at screen printing method. In screen printing, the need of high definition printing is gradually increasing according to developing special inks. A conventional haftone, so called AM screening, is simple and easy to implement, but the haftone dot patterns by using this method are not free for the moire fringe. This paper is used densitometry and image analysis to investigate relation with printing according to screen mesh, opening size and resolution of copy in image reproduction used FM screen. We had the good result of dot gain and tone reproduction on the screen printing of high definition using FM screen.

• 대한공간정보학회지
• /
• 제16권2호
• /
• pp.87-95
• /
• 2008

Ladar (LAser Detection And Ranging, Lidar)는 레이저 신호를 이용하여 대상지역에 대하여 정밀한 3차원 거리를 취득하는 센서로 최근 들어 미사일, 항공기 등에 탑재되어 자동표적인식 등에 활용되고 있다. 기존의 영상기반센서와 달리 센서와 표적과의 거리를 밝기나 색상 값으로 표현한 range 영상을 제공하며, 이로부터 표적의 정밀한 3차원 모델의 생성이 가능하기 때문에 표적의 인식과 식별을 가능하게 한다. 이러한 Ladar 센서의 데이터를 모의 생성한다면, 센서의 개선 및 개발 또는 센서 데이터 처리 알고리즘의 개발을 더욱 효율적으로 수행할 수 있게 될 것이다. 이에 본 연구에서는 특히 Linear FM 기반의 Ladar 센서의 신호 생성 및 신호처리 과정을 시뮬레이션하여 Ladar 영상을 모의 생성하고자 한다. 이를 위해 본 연구에서는 우선 FM chirp modulator를 탑재한 시스템의 레이저 신호를 모의로 생성하고, FFT기반 신호처리를 통해 센서와 표적과의 거리를 획득하였으며, 최종적으로 Ladar range 영상을 성공적으로 모의 생성하였다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권2호
• /
• pp.202-207
• /
• 2015

A CMOS relaxation oscillator, with high robustness over process, voltage and temperature (PVT) variations, is designed in $0.18{\mu}m$ CMOS. The proposed oscillator, consisting of full-differential charge-discharge timing circuit and switched-capacitor based voltage-to-current conversion, could be expanded to a simple open-loop frequency synthesizer (FS) with output frequency digitally tuned. Experimental results show that the proposed oscillator conducts subcarrier generation for frequency-modulated ultra-wideband (FM-UWB) transmitters with triangular amplitude distortion less than 1%, and achieves frequency deviation less than 8% under PVT and phase noise of -112 dBc/Hz at 1 MHz offset frequency. Under oscillation frequency of 10.5 MHz, the presented design has the relative FS error less than 2% for subcarrier generation and the power dissipation of 0.6 mW from a 1.8 V supply.

• 한국수산과학회지
• /
• 제31권4호
• /
• pp.471-476
• /
• 1998

우리나라 남해안의 다획성 어종인 고등어로부터 부패 활성이 강한 효모를 분리하여 그 균학적 특성을 조사하고 어육의 부패에 미치는 영향을 조사한 결과를 요약하면 다음과 같다. 1. 고등어로부터 분리된 효모 14균주 중 12균주 ($86\%$)가 저온성 효모였으며, 6균주 ($43\%$)가 단백분해활성을 가지는 것으로 나타났다. 2. 분리된 효모 14균주 중 저온생육능 및 단백분해능이 가장 강한 Y-5가 C. lipolytica로 동정되어 C. lipolytica FM5로 명명하였다. 3. C. lipolytica FM5의 최적 생육조건은 $25^{\circ}C$, pH 7.0이었으며, 염농도 $10\%$에서도 생육이 가능하여 강한 내염성을 나타내었다. 4. 멸균어육을 이용한 부패실험에서 C. lipolytica FM5를 접종한 경우 $5^{\circ}C$, $15^{\circ}C$, $25^{\circ}C$에서 저장 1주일만에 VBN생성량이 각각 50mg-N/100g, 152mg-N/100g, 379mg-N/100g를 나타내어, 대표적인 어류부패세균인 Ps. fluorescens ATCC 17571을 접종한 경우와 유사한 속도로 부패가 진행되었다.

• 한국환경과학회지
• /
• 제26권6호
• /
• pp.779-788
• /
• 2017

In this study, we analyzed the changes in the echolocation and prey-capture behavior of the horseshoe bat Rhinolophus ferrumequinum from search phase to capture time. The experiment was conducted in an indoor free-flight room fitted with an ultra-high-speed camera. We found that the bats searched for food while hanging from a structure, and capturing was carried out using the flight membrane. In addition, it was confirmed that the mouth and uropatagium were continuously used in tandem during the capturing process. Furthermore, using Constant Frequency (CF), we confirmed that the prey catching method reflected the wing morphology and echolocation pattern of R. ferrumequinum. The echolocation analysis revealed that the pulse duration, pulse interval, peak frequency, start-FM-bandwidth, and CF duration decreased as the search phase approached the terminal phase. Detailed analysis of echolocation pulse showed that the end-FM bandwidth, which increases as it gets nearer to the capture time of prey, was closely related to the accurate grasp of the location of an insect. At the final moment of prey capture, the passive listening that stopped the divergence of the echolocation was identified; this was determined to be the process of minimizing the interruption from the echo of the echolocation call emitted from the bat itself and sound waves emitted from the prey.

• 제어로봇시스템학회논문지
• /
• 제11권6호
• /
• pp.518-523
• /
• 2005

Strip off-center is one of the major problems in hot strip mill line. The key to good centering is having good equipment, modern control systems, excellent maintenance and an understanding of milling process. Therefore, this study aims to develop a system that is useful for quantitative analysis of strip off-center. In this study, the measuring method of strip off-center was thoroughly studied and the exclusive control board to line scan camera were designed. Also, the manipulated type housing for line scan camera was developed to adjust initial parameters for strip width and center line. In order to check the accuracy and usefulness of the developed system, FM stand in $\#2$ Hot Strip Factory in Pohang Steel Works was targeted.

• 전자공학회논문지A
• /
• 제29A권8호
• /
• pp.1-9
• /
• 1992

Radio data system is a next-generation broadcasting system of digital information communication which multiplexes the digital data into the FM stereo signal in VHF/FM band and provides important and convenient service features. And radio data are composed of groups which are divided into 4 blocks with information word and check word. In this paper, radio data receiver is developed which recovers and process radio data to provide services. Then we confirm that 7dB SNR is required to be 10S0-5TBER of demodulation. Deconding process of shortened-cyclic-decoder has been simulated by computer. Also, the time-compression (by 16 times) method has been adopted for the RDS features post-processing. Via the error probability calculation, simulation and experimentation, the developed receiver system is proved to satisfy the system specification of EBU and implemented by general logic gates and analog circuits.