• 전기학회논문지
• /
• 제59권9호
• /
• pp.1611-1614
• /
• 2010

The explosion of a nuclear weapon radiates a gamma-ray in the form of a transient pulse. If the gamma-ray introduces to semiconductor devices, much Electron-Hole Pairs(EHPs) are generated in depletion region of the devices[7]. as a consequence of that, high photocurrent is created and causes upset, latchup and burnout of semiconductor devices[8]. This phenomenon is known for Transient Radiation Effects on Electronics(TREE), also called dose-rate effects. In this paper 3D structure of inverter and NAND gate device was designed and transient pulse gamma-ray was modeled. So simulation for transient radiation effect on inverter and NAND gate was accomplished and mechanism for upset and latchup was analyzed.

• 전기학회논문지
• /
• 제61권3호
• /
• pp.422-426
• /
• 2012

Transient radiation is emitted during a nuclear explosion. Transient radiation causes a fatal error in the CMOS circuit as a Upset and Latch-up. In this paper, transient radiation NMOS, PMOS, INVERTER SPICE model was proposed on the basisi of transient radiation effects analysis using TCAD(Technology Computer Aided Design). Photocurrent generated from the MOSFET internal PN junction was expressed to the current source and Latch-up phenomenon in the INVERTER was expressed to parasitic thyristor for the transient radiation SPICE model. For example, the proposed transient radiation SPICE model was applied to CMOS NAND circuit. SPICE simulated characteristics were similar to the TCAD simulation results. Simulation time was reduced to 120 times compared to TCAD simulation.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제14권5호
• /
• pp.609-614
• /
• 2014

The fringe field effects on the transient characteristics of nano-electromechanical (NEM) memory cells have been discussed by using an analytical model. The influence of fringe field becomes stronger as the size of a cell decreases. By using the proposed model, the dependency of NEM memory transient characteristics on cell parameters has been evaluated.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제1권1호
• /
• pp.13-19
• /
• 2009

The primary objective of this paper is to investigate the dynamic stability and survivability of a four-column classic TLP (tension-leg platform) under less-than-extreme storm conditions where one or more tendons have been lost due to damage or disconnect. The transient responses of the platform and tendon tensions at the moment of disconnection are particularly underscored. The numerical simulation is based on the BE-FE hybrid hull-tendon-riser coupled dynamic analysis in time domain. Compared to the common industry practice of checking the system without a failed tendon in the beginning, the maximum tension on the neighboring tendon can be significantly increased at the moment of disconnection due to the snap-like transient effects, which can lead to unexpected failure of the total system. It is also found that the transient effects can be reduced with the presence of TTRs (top-tensioned risers) with pneumatic tensioners. It is also seen that the TLP cannot survive in the 100-yr hurricane condition after losing one tendon.

• 한국초전도ㆍ저온공학회논문지
• /
• 제4권2호
• /
• pp.68-72
• /
• 2002

This work investigates the transient cooling characteristics of an Infrared (IR) detector cryochamber, which has a critical effect on the cooling load. The current thermal modeling considers the conduction heat transfer through a cold well. the gaseous conduction due to outgassing. and the radiation heat transfer. The transient cooling Performance. i.e. the penetration depth and cooling load, is determined using a finite difference method. It is found that the penetration depth increases as the bore conductivity increases. Gaseous conduction and radiation hardly affect the penetration depth. The transient cooling load increases as the bore conductivity increases. The effects of gaseous conduction and radiation on transient heat transfer are weak at initial stages of cooling. However, their effects become significant as the cooling Process Proceeds.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.1185-1186
• /
• 2008

A nuclear explosion emits a transient radiation pulse like gamma rays. Gamma rays have a high energy and cause unexpected effects in semiconductor devices. These effects are mainly referred to dose-rate latcup and dose-rate upset. By transient radiation pulse in CMOS devices, dose-rate latchup is simulated in this paper.

• Nuclear Engineering and Technology
• /
• 제53권1호
• /
• pp.322-336
• /
• 2021

This paper presents a numerical prediction of the transient hydraulic loads acting on the tubes and external supports of a pressurized water reactor (PWR) steam generator (SG) during blowdown following a sudden feedwater line break (FWLB). A simplified SG model was used to easily demonstrate the prediction. The blowdown discharge flow was treated as a flashing flow to realistically simulate the transient flow fields inside the SG and the connected broken feedwater pipe. The effects of the SG initial pressure or the broken feedwater pipe length on the intensities or magnitudes of transient hydraulic loads were investigated. Then predictions of the decompression pressure wave-induced impulsive pressure differential loads on SG tubes and the transient blowdown loads on SG external supports were demonstrated and the general aspects of transient responses of such transient hydraulic loads to the FWLB were discussed.

• Korean Journal of Acupuncture
• /
• 제19권1호
• /
• pp.35-45
• /
• 2002

Acupuncture and herbal medicine have been used to prevent and treat the cerebrovascular accident, such as a stroke, and many studies of acupuncture and moxibustion concerning to the stroke have been undertaken in the human and various animals. However, it was not published the protective effect of the electroacupuncture (EA) of Huan-do (GB30) on the transient forebrain ischemia injury. The neuroprotective effects of EA (2 ms, 10 Hz, and 1 - 2 mA) of GB30 on the transient forebrain ischemia injury was investigated by western blot of nNOS and hematoxylin and eosin stain in Sprague-Dawley rats. The transient forebrain ischemia injury resulted in increased expression of nNOS in the brain for 6 hrs after ischemia, and EA decreased significantly expression of nNOS protein in brain increased by transient forebrain ischemia injury. The survived neuronal cell stained with hematoxylin and eosin (H&E) decreased in the hippocampus by the 7 days after ischemia comparing with the normal. Comparing with the normal, the survived neurons seriously decreased cell in the hippocampus after the injury. However, the proportion of survived neurons was increased in EA treatment. These results suggest that EA of GB30 have neuroprotective effects on transient forebrain ischemia injury.

• 대한토목학회논문집
• /
• 제26권6B호
• /
• pp.623-631
• /
• 2006

본 연구에서는 하상변화가 존재하는 자연하천에서의 물질거동을 해석하기 위한 주기적저장대모형을 개발하였다. 저장대 구조에 따른 저장효과를 살펴보기 위하여 자연하천의 특성을 고려한 4개의 주기적 여울-소 구조를 갖는 와 흐름에서 소금물과 염료를 이용하여 실험한 모형실험결과를 이용하였다. 염료실험 결과, 물질이동 및 혼합거동은 하상 및 하안의 구조에 영향을 받는 것으로 나타났다. 기존의 저장대분산모형이 주기적으로 변화하는 저장대 구조에 의한 이동 및 질량교환 효과를 정확히 재현하지 못하는 것에 비해서 경계변화에 따른 질량교환 효과를 보다 효과적으로 재현할 수 있는 주기적저장대모형은 모형 실험 결과를 잘 재현하는 것으로 나타났다. 새로운 저장대모형을 미국 텍사스주의 Sabin River에 적용하였으며, 그 결과는 실험을 통해서 수집된 농도분포를 잘 재현하는 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2004년도 ICCAS
• /
• pp.736-740
• /
• 2004

In order to overcome the problems of simulation methods, the power system transient stability assessment method using critical fault clearing time functions has been developed. Using the above method, this paper has developed the new method which can assess accurately and efficiently the effects of control and protection systems on transient stability which is the most important characteristic to assess in power systems. At first, critical fault clearing time functions CCT(W:load) are defined by taking notice of the fact that transient stability is mainly controlled by fault clearing time and load. Next, the method to be enable to assess accurately and efficiently the effects of control and protection systems on transient stability has been newly developed by using the above functions. Finally, it has been applied to the effect assessment in the occurrence of a three-phase fault in a model power system. Results of application have been clarified its effectiveness.