• Nuclear Engineering and Technology
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• 제42권3호
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• pp.271-278
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• 2010

While the deterministic lattice physics/depletion codes use leakage-corrected critical spectrum (although approximate due to the B1 buckling search employed), Monte Carlo depletion codes currently in use do not have such a feature in spite of their heterogeneity and continuous-energy modeling capability. This paper describes an approach to Monte Carlo depletion with leakage-corrected critical spectrum derived from first principles. This is based on the concept of albedo eigenvalue treated as weight of the reflected neutron in Monte Carlo simulation.

• 생태와환경
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• 제45권1호
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• pp.34-41
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• 2012

The variation of dissolved oxygen (DO) was monitored with high frequency by an automatic data-logging sensor in a eutrophic urban stream (the Anyang Stream) located in a metropolitan area of Seoul, South Korea. In general, DO showed the diel variation of increase in daytime and decrease at night, implying that primary production is a major mechanism of oxygen supply in this ecosystem. The fluctuation of oxygen was determined by rainfall. DO depletion was most obvious after a rainfall resulting in an anoxic condition for a day, which is thought to be caused by scouring of periphyton and organic ooze at the stream bottom. Seasonally DO was higher in winter and frequently depleted in warm seasons. DO depletion was often at a dangerous level for fish survival. Fish survey showed that little fish was living at the study site and oxygen depletion may be the major stress factor for aquatic animals. From the results it can be suggested that a high frequency monitoring of oxygen should be established for the proper assessment of aquatic habitats and better management strategy.

• 한국물환경학회지
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• 제37권1호
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• pp.1-9
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• 2021

The depletion of dissolved oxygen (DO) in urban streams has a profound effect on the aquatic ecosystem; however, the change in DO by resuspension of sediments and the cause have not been sufficiently investigated. In this study, the physicochemical properties (particle size, and the content of organic and heavy metals) of the sediments of an urban stream (Anyang Stream) and the characteristics of water quality changes (DO, dissolved organic carbon (DOC), dissolved nitrogen (DN), sediment oxygen demand (SOD), and adenosine triphosphate (ATP)) by sediment resuspension were investigated. The sediment content of fine particles (< 0.2 mm) increased from 36.7% to 52.7% from the upstream to the downstream, and the contents of heavy metals and organic matter of the sediment were also higher towards the downstream. The depletion of DO by resuspension was observed in the sediment at the downstream sites (P8, P9), where the fine particle content was high, and biological SOD (BSOD) was more than 88% compared to the total SOD. The increase in BSOD coincided with the increase in ATP. It was also confirmed that the depletion of DO could increase the amount of heavy metals (such as Fe, Mn, and Pb) released from the sediment. Based on the above results, it can be concluded that resuspension of sediments induces rapid water quality changes and may cause accidents, such as fish mortality, during rainfall, and such a water quality effect can be more pronounced in sediments with a high content of fine particles and organic matter and high biological activity.

• Transactions on Electrical and Electronic Materials
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• 제14권4호
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• pp.177-181
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• 2013

In this paper, silicon solar cells are analyzed regarding power conversion efficiency by changed capacitance in the depletion region. For the capacitance control in the depletion region of silicon solar cell was applied for 10, 20, 40, 80, 160 and 320 Hz frequency band character and alternating current(AC) voltage with square wave of 0.2~1.4 V. Academically, symmetry formation of positive and negative change of the p-n junction is similar to the physical effect of capacitance. According to the experiment result, because input of square wave with alternating current(AC) voltage could be observed to changed capacitance effect by indirectly method through non-linear power conversion (Voltage-Current) output. In addition, when input alternating current(AC) voltage in the silicon solar cell, changed capacitance of depletion region with the forward bias condition and reverse bias condition gave a direct effect to the charge mobility.

• 한국콘텐츠학회논문지
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• 제16권10호
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• pp.467-476
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• 2016

정보통신기술의 발달을 기반으로 창업을 하는 영세 업체와 가택 근무 환경(Small Office Home Office: SOHO)이 늘고 있다. SOHO는 대부분 인터넷을 통해 업무를 처리하고 Wi-Fi의 이용이 일반화되어 있다. 무선통신환경은 쉽게 서비스거부(Denial of Service: DoS) 공격으로 통신에 장애가 생겨 업무환경 및 고객서비스에 영향을 받을 수 있다. 이를 방어하기 위한 방안으로 무선침입탐지시스템(Wireless Intrusion Detection System: WIDS)이 있다. 그러나 시중 WIDS는 구축비용이 비싸며, 관리 부담이 높아 자본력과 인력이 낮은 SOHO환경에서 사용하기에 어려움이 따른다. 본 논문에서는 관리운영의 부담을 줄이고 간단히 공격 위협을 인식할 수 있는 SOHO 환경을 위한 Smart WIDS를 제안하고 구현하였다. Raspberry Pi2를 Smart WIDS의 연산장치로 사용하고, 안드로이드 스마트폰을 Smart WIDS의 연계 공격감지 알림 인터페이스로 제공한다. Smart WIDS는 IEEE 802.11 기반의 Masquerading DoS 와 Resource Depletion DoS을 감지하여, WI-FI의 Pre-shared Key(PSK) 획득과 중간자 공격 시도나 서비스 제공을 방해하는 공격을 감지할 수 있다. 또 안드로이드 스마트폰은 해당 WI-FI의 감지된 공격을 관리자에게 알리며, 관리의 편의성을 제공한다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2018년도 정기학술대회 발표논문집
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• pp.235-235
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• 2018

• The Korean Journal of Ecology
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• 제18권2호
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• pp.243-253
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• 1995

Seral changes in environmental factors and recovery of soil fertility during abandoned field succession after shifting cultivation were investigated in eastern Kangwon-Do, Korea. Relative light intensity of herb and shrub layer decreased gradually until 50 years and increased slightly thereafter. Amount of litter and nutrients derived from it were depicted as a parabola form showing the gradual increment during the first 50 years and slight decrease thereafter. Organic matter, pH value, total-N and Mg of soil were plotted as an early depletion-mid pinnacle form showing the extrems depletion during the first 10 years, abrupt increase in about 20 or 50 years and gradual decrease thereafter. Ca, Al, Mn and Na of soil were depicted as a pinnacle form showing the peak in about 20 or 50 years. Thickness and field capacity of soil increased gradually, but K and total-P did not show any tendency as succession proceeded. The soil fertility, overall capacity of soil nutrients and water for plant growth, was plotted as the early depletion-mid pinnacle form.

• 한국세라믹학회지
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• 제45권5호
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• pp.280-284
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• 2008

In order to investigate residence time effect on the growth of ZrC film, the ZrC films grew with various system total pressure (P) and total flow rate (Q) by low pressure chemical vapor deposition because residence time is function of system total pressure and total flow rate. Thermodynamic calculations predict that the decomposition of source gases ($ZrCl_4$ and $CH_4$) would be low as increasing the residence time. Thermodynamic calculations results were proved by investigating deposition rate with various residence time. Deposition rate decreased with residence time of source gas increased. Besides, depletion effect accelerated diminution of deposition rate at high residence time. On the other hands, the deposition rated was increased as decreasing the residence time because fast moving of intermediate gas species decrease the depletion effect. The crystal structure was not changed with residence time. However, the largest size of faceted grain showed up to specific residence time and the size of grain was decreased whether residence time increase or not.

• Corrosion Science and Technology
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• 제17권4호
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• pp.183-192
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• 2018

스테인리스강은 오스테니틱 스테인리스강, 페리틱 스테인리스강과 마르텐시틱 스테인리스강으로 대별할 수 있으며, 이 고도의 안전성이 요구되는 산업계에서 스테인리스강의 입계부식, 응력부식균열과 핏팅과 같은 국부적 부식이 발생하면 대형사고로 귀결될 수 있다. 스테인리스강의 입계부식 기구와 대책 그리고 입계부식측정 방법에 대한 기술 소개를 하여 산업현장에서 흔히 접하는 스테인리스강 예민화에 대한 길잡이가 되도록 하고, 이 분야를 전문적으로 연구하려는 연구자에게 예민화 전반을 이해하는데 활용되도록 하였다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.70-75
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• 1997

A CASMO/ORIGEN coupling utility program was developed to predict the composition of all the fission products in spent PWR fuels. The coupling program reads the CASMO output file, modifies the ORIGEN cross section library and reconstructs the ORIGEN input file at each depletion step. In ORIGEN, the burnup equation is solved for actinides and fission products based on the fission reaction rates and depletion flux of CASMO. A sample calculation has been performed using a 14$\times$14 PWR fuel assembly and the results are given in this paper.