• Fisheries and Aquatic Sciences
• /
• 제1권1호
• /
• pp.48-62
• /
• 1998

Seasonal volume transport on the Texas-Louisiana continental shelf is investigated in terms of objectively fitted transport streamfunction fields based on the current meter data of the Texas­Louisiana Shelf Circulation and Transport Processes Study. Adopted here for the objective mapping is a method employing a two-dimensional truncated Fourier representation of the streamfunction over a domain, with the amplitudes determined by least square fit of the observation. The fitting was done with depth-averaged flow rather than depth-integrated flow to reduce the root-mean-square error. The fitting process filters out $11\%$ of the kinetic energy in the monthly mean transport fields. The shelf-wide pattern of streamfunction fields is similar to that of near-surface velocity fields over the region. The nearshore transport, about 0.1 to 0.3 Sv $(1 Sv= 10^6\;m^3/sec)$, is well correlated with the seasonal signal of along-shelf wind stress. The spring transport is weak compared to other seasons in the inner shelf region. The transport along the shelf break is large and variable. In the southwestern shelf break, transport amounts up to 4.7 Sv, which is associated with the activities of the encroaching of energetic anticyclonic eddies originated in Loop Current of the eastern Gulf of Mexico. The first empirical orthogonal function (EOF) of streamfunction variability contains $67.3\%$ of the variance and shows a simple, shelf-wide, along-shelf pattern of transport. The amplitude evolution of the first EOF is highly correlated (correlation coefficient: 0.88) with the evolution of the along-shelf wind stress. This provides strong evidence that the large portion of seasonal variation of the shelf transport is wind-forced. The second EOF contains $23.7\%$ of the variance and shows eddy activities at the southwestern shelf break. The correlation coefficient between the amplitudes of the second EOF and wind stress is 0.42. We assume that this mode is coupled a periodic inner shelf process with a non-periodic eddy process on the shelf break. The third EOF (accounting for $7.2\% of the variance) shows several cell structures near the shelf break associated with the variability of the Loop Current Eddies. The amplitude time series of the third EOF show little correlation with the along-shelf wind.

• 한국환경과학회지
• /
• 제6권4호
• /
• pp.323-333
• /
• 1997

본 연구는 해양에서 비규칙적으로 관측된 유속자료를 이용 속도유선함수를 객관적해석을 통하여 산출하였다. 이를 위하여 헬름흘쯔(Helmholtz)정리를 응용 2차원 유속장의 비발산 부분만 나타내는 유선함수와 와도와의 관계를 규정하는 포이송(Poisson)방정식을 도출하고, 혼합경계조건과 관측치로부터 산출된 와도장을 이용 유선함수를 구하였다. 위의 방법을 실현하기 위하여 텍사스-루이지아나 대륙붕 순환 및 수송 연구(LATEX측 일환으로 텍사스-루이지아나 대륙붕의 31개 정점에서 32개월(1992년 4월 SIM 1994년 11월)간 관측된 해류계자료를 이용하였다. 본 방법으로 산출된 텍사스-루이지아나 대륙붕의 속도유선함수는 관측치와 잘 일치하였다. 본 연구에서 산출된 유선함수는 특정 해역의 저주파 운동의 이해뿐만 아니라 기름유출, 영양염 및 플랑크톤 수송과 관련한 환경유동모델의 초기화 및 검증에 응용될 것으로 기대된다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.361-361
• /
• 2009

KEPCO High Temperature Superconducting (HTS) cable system rated with $3\Phi$, 22.9kV, 1250A was laid in 2006, and the long term test is in progress. The HTS cable system with the cooling system has been operated below cryogenic temperature. That environment exposes the system to the thermo-mechanical stress due to the significant temperature difference, and the cooling system has moving parts for the forced circulation of the coolant. Therefore the HTS cable system experiences thermal fatigue and moving part such as liquid nitrogen pump need a regular replacement every 5000 hours Building the assessment criterion, the maintenance procedure was established and regular preventive maintenance was done; improvement of the termination structure and the replacement of the bearing of liquid nitrogen pump. Following the proper process, the reliability assessment test including He leakage detection and the stability of flow rate was performed. This paper describes the process and result of the first regular maintenance of KEPCO HTS cable system

• 한국환경과학회지
• /
• 제7권1호
• /
• pp.27-35
• /
• 1998

The present study intends to investigate the transient response of an atmosphere /ocean general circulation model to a gradual Increase of atmospheric carbon dioxide. To detect the climatic change of the for 1% $CO_2$ run with increasing $CO_2$ and the control run with fried $CO_2$ are compared. From response of the surface air temperature due to the gradual increase of atmospheric carbon dioxide is slowly increased with latitudes and is clearly larger over continents than oceans. The annual goffal mean temperature is continuously increased with 0.03552 per one year with strong SIN ratio and distinguished from the natural variability The time dependent response of the gradual increasing $CO_2$ has the strong seasonal variability with small change In summer and large change in winter, and the strong regional In the Asian and the American continents. It has been suggested that the direct and the feedback processes in the climate systems should be investigated by the detailed sensitivity runs to get the meaninguul estimate of the $CO_2$ forced variability.

• 한국실내디자인학회논문집
• /
• 제14권6호
• /
• pp.236-243
• /
• 2005

The pre-examination closely beforehand relation between the articles on exhibition and visitors, the visitors and exhibition space, the exhibition space and the articles on exhibition, and the acceptance of various requirements are the matters you should consider in the initial stage when planning the establishment of a museum. Especially, the clear guideline for the layout of exhibition to meet the intention of spectators considered based on the seeing behavior in the exhibition hall (i.e. they see the articles on exhibition in order passively under instructions of the museum or select them by themselves positively etc.), and the moving line of appreciation and the exhibition type seems to be not yet prepared sufficiently. This study can be defined as the study of fundamental background for the architectural guideline for the characteristics of visitor's behavior, the selected moving line in the exhibition hall, the layout against the forced moving line and the type of exhibition space. As a part of this study, we carried out the research and the study for how the movement of visitors and the characteristics of seeing behaviors according to the type of the moving line are shown, based on the type of moving line for seeing suggested by David Dean.

• Ocean and Polar Research
• /
• 제23권2호
• /
• pp.181-188
• /
• 2001

We describe here the Korea ocean prediction system that closely resembles operational numerical weather prediction systems. This prediction system will be served for real-time forecasts. The core of the system is a three-dimensional primitive equation numerical circulation model, based on ${\sigma}$-coordinate. Remotely sensed multi-channel sea surface temperature (MCSST) is imposed at the surface. Residual subsurface temperature is assimilated through the relationship between vertical temperature structure function and residual of sea surface height (RSSH) using an optimal interpolation scheme. A unified grid system, named as [K-E-Y], that covers the entire seas around Korea is used. We present and compare hindcasting results during 1990-1999 from a model forced by MCSST without incorporating RSSH data assimilation and the one with both MCSST and RSSH assimilated. The data assimilation is applied only in the East Sea, hence the comparison focuses principally on the mesoscale features prevalent in the East Sea. It is shown that the model with the data assimilation exhibits considerable skill in simulating both the permanent and transient mesoscale features in the East Sea.

• 한국초전도ㆍ저온공학회논문지
• /
• 제20권2호
• /
• pp.34-39
• /
• 2018

A cryogenic cooling system is designed for a 154 kV/ 2 kA three-phase hybrid type superconducting fault current limiter (SFCL). The superconducting modules of the SFCL have the operating condition of 71 K at 500 kPa. The total heat load of the SFCL including the cooling system is estimated at 9.6 kW. The cooling system of the closed loop is configured to meet the operating condition, depending on cooling methods of forced flow cooling and re-liquefaction cooling. The cooling system is composed of three cryostats with superconducting modules, cryocoolers, liquid nitrogen circulation pumps, a subcooler and a pressure builder. The basic cooling concept is to circulate liquid nitrogen between three SFCL cryostats and the cryocooler, while maintaining the operating pressure. The design criterion for the cooling system is based on the operation results of the cooling system for a 154 kV/2 kA single-phase hybrid SFCL. The specifications of system components including the piping system are determined according to the design criterion.

• Nuclear Engineering and Technology
• /
• 제17권1호
• /
• pp.16-24
• /
• 1985

풀형 고속증식로에서의 과도 현상을 모사할 수 있는 전산 모델이 개발되었다. 이 전산 모델 SIM-FARP는 어떠한 펌프로의 전원 상실사고나 완전한 강제냉각 상실사고, 그리고 자연순환 과정 등을 모사할 수 있는 Fast Running Computer Code이다. 이에 따라 8개의 지배방정식이 유도되었으며, 이8개의 미분 방정식을 풀기 위해 Runge-Kutta의 수치해석방법이 사용되었다. 개발된 전산 프로그램은 두 가지 예제에 적용되었는데 이는 Super-Phenix-I에서의 펌프에의 전원상실사고 및 원자로가 정지되지 않는 상태에서의 외부전원 상실사고이다.

• Nuclear Engineering and Technology
• /
• 제19권2호
• /
• pp.77-84
• /
• 1987

격납용기 구분방 내에서 정화한 열전달 상관식을 얻기 위해 HDR 실험 자료들을 통계적 인 방법으로 분석하였다. 세가지의 blowdown 시험, 즉 V.42, V.43 and V.44를 통해 얻어진 열전달 자료들이 상관식을 유도하는데 사용되었다. 이미 Uchida에 의해 제안되었던 air-to-steam 질량비는 이 실험에서도 역시 가장 중요한 인자로 입증되었다. 이 연구에서는 Uchida의 열전달 상관식으로 만족되지 않은 실험자료들을, 격납용기 대기와 벽 표면의 온도차의 함수로, 또 대기 압력의 함수로 표시하여 수정하려고 시도하였다. 이 종속성외에도 대기의 난류도와 시간에 따른 인자가 고려되어야 한다. 그러나 HDR 계획에서는 흐름속도의 측정 자료가 부정확하기 때문에 정량적인 관계식의 유도는 힘들다. 다만 열전달 계수와 온도 차이의 관계가 밀접하다는 사실을 밝혔으며 특히 강제순환 조건에서 더욱 이 관계는 명백해짐을 볼 수 있다.

• Nuclear Engineering and Technology
• /
• 제51권1호
• /
• pp.116-124
• /
• 2019

$M^2LFR-1000$ is a medium-power modular lead-cooled fast reactor, developed by University of Science and Technology of China (USTC), aiming at achieving a reactor design fulfilling the Gen IV nuclear system requirements and meanwhile emphasizing the optimum safety and economics. In order to evaluate the safety performance of $M^2LFR-1000$ reactor core, three typical transients are selected from initiating events, which are unprotected transient overpower (UTOP), unprotected loss of offsite power (ULOHS+ULOF) and increase of feedwater flowrate with primary pumps trip (IFW+PLOF). These three transients presented and discussed in this paper are performed with the code Analysis of THermal-hydraulics of LEaks and Transients (ATHLET), which is developed by Gesellschaft $f{\ddot{u}}r$ Anlagen-und Reaktorsicherheit gGmbH (GRS). The results indicate that the $M^2LFR$ is safe enough under these three transients due to the good inherent safety features of the reactor, without human intervention, the reactor will reach a new steady state under UTOP condition.