• 한국안광학회지
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• 제12권1호
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• pp.69-74
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• 2007

펄스형 방전플라스마장치에서 축방향 플라스마 curren sheath의 속력을 측정하였고, snowplow 모델과 비교하였다. Current sheath의 속력은 $10^6cm/s$로 측정되었다. 측정된 속력 중에서 가벼운 기체인 수소와 헬륨은 모델의 이론과 비슷한 결과가 나왔으나 무거운 기체인 아르곤은 이론과 조금 벗어났다. 그 이유는 current sheath의 불안정성 때문으로 추정된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1014-1019
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• 2005

In this paper, a neural network technique for automatic steering control of a four wheel drive autonomous highway snowplow vehicle is presented. Controllers are designed by the LQR method based on the vehicle model. Then, neural network is used as an auxiliary controller to minimize lateral tracking error under the presence of load. Simulation studies of LQR control and neural network control are conducted for the vehicle model under a virtual snowplowing situation. Tracking performances are also compared for two and four wheeled steering vehicles.

• 대한임베디드공학회논문지
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• 제6권3호
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• pp.132-138
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• 2011

This paper presents an intelligent control approach for lateral position control of an autonomous four wheel steered snowplowing robotic vehicle. The vehicle is built for removing snow on the highway. Dynamics of the vehicle is derived and linearized for LQR control. Lateral position is controlled by the LQR method first, then the neural network control technique is introduced to improve tracking performances under the presence of load. The feasibility of using four wheel steering control is investigated by simulation studies of lateral position tracking of the Ford F-250 truck model. Performances of a LQR control method and a neural network control method under virtual snowplowing situation are compared.

• 천문학회지
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• 제48권2호
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• pp.139-154
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• 2015

We carry out three-dimensional hydrodynamic simulations of the supernova remnants (SNRs) produced inside molecular clouds (MCs) near their surface using the HLL code (Harten et al. 1983). We explore the dynamical evolution and the X-ray morphology of SNRs after breaking through the MC surface for ranges of the explosion depths below the surface and the density ratios of the clouds to the intercloud media (ICM). We find that if an SNR breaks out through an MC surface in its Sedov stage, the outermost dense shell of the remnant is divided into several layers. The divided layers are subject to the Rayleigh-Taylor instability and fragmented. On the other hand, if an SNR breaks through an MC after the remnant enters the snowplow phase, the radiative shell is not divided to layers. We also compare the predictions of previous analytic solutions for the expansion of SNRs in stratified media with our onedimensional simulations. Moreover, we produce synthetic X-ray surface brightness in order to research the center-bright X-ray morphology shown in thermal composite SNRs. In the late stages, a breakout SNR shows the center-bright X-ray morphology inside an MC in our results. We apply our model to the observational results of the X-ray morphology of the thermal composite SNR 3C 391.

• Nuclear Engineering and Technology
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• 제12권3호
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• pp.163-170
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• 1980

4KJ의 에너지 뱅크(16.5KV, 35nH)를 사용하여 Mather형의 플라즈마총을 1 torr이하의 낮은 기체압력에서 동작시키면서 플라즈마의 효율적인 집속조건을 구하였다. 중수소기체의 충전압력이 0.18torr, 저장에너지가 3.8KJ일때 방전전류의 최고치는 180KA이었고 플라즈마의 축방향 평균속도는 약 $7cm/\mu\textrm{s}$이었다. 이것은 snowplow모델에 의해 계산된 속도보다 작은 값인데 이는 절연재 표면을 통한 전류의 손실에 기인하는 것으로 생각된다. H. Bruzzone의 플라즈마 집속장치(1KJ, 16KV, $4.2\mu\textrm{s}$)에 비해 본 실험에서는 기체압력이 낮은 역역에서 플라즈마 접속이 일어났다. 이는 이 실험에서 사용한 플라즈마총의 크기가 저장에너지에 비해 크고 또 잔여기체의 함량이 비교적 높기 때문이다. 집속된 플라즈마로 부터 방출되는 중성자는 Long counter를 사용해서 계측했다.