• Journal of Mechanical Science and Technology
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• 제16권9호
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• pp.1033-1039
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• 2002

Partial penetration welding joint refers to the groove weld that applies to the one side welding which does not use steel backing and to both side welding without back gouging, that is, the partial penetration welding joint leaves an unwelded portion at the root of the welding area. In this study, we analyzed the residual stress and fracture on the thick metal plates that introduced the partial penetration welding method. According to the above-mentioned welding method, we could draw a conclusion that longitudinal stress and traverse stress occurred around the welding area are so minimal and do not affect any influence. We also performed the fracture behavior evaluation on the partial penetration multi pass welding with 25.4 mm thick plate by using the J-integral, which finally led us the conclusion that the partial penetration multi-pass welding method is more applicable and effective in handling the root face with less than 6.35 mm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.501-502
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• 2016

매칭 회로는 유도성전력을 소나시스템에 공급함으로써 에너지 손실과 소나시스템의 크기를 줄일 수 있다. 이 논문에서는 적응 정합회로라고 불리는 가변인덕터로 구성된 기본적인 매칭회로의 토폴로지를 제시하였다. 전력회로는 소나시스템에서 사용되는 범위의 주파수와 전력에 기반하여 설계되었다. 또한 제시된 정합회로의 특성을 시뮬레이션을 통해 증명하였다.

• The Plant Pathology Journal
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• 제36권4호
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• pp.335-345
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• 2020

Tomato grey mould has been one of the destructive fungal diseases during tomato production. Ten mM of menadione sodium bisulfite (MSB) was applied to tomato plants for eco-friendly control of the grey mould. MSB-reduced tomato grey mould in the 3rd true leaves was prolonged at least 7 days prior to the fungal inoculation of two inoculum densities (2 × 10⁴ and 2 × 10⁵ conidia/ml) of Botrytis cinerea. Protection efficacy was significantly higher in the leaves inoculated with the lower disease pressure of conidial suspension compared to the higher one. MSB-pretreatment was not effective to arrest oxalic acid-triggered necrosis on tomato leaves. Plant cell death and hydrogen peroxide accumulation were restricted in necrotic lesions of the B. cinereainoculated leaves by the MSB-pretreatment. Decreased conidia number and germ-tube elongation of B. cinerea were found at 10 h, and mycelial growth was also impeded at 24 h on the MSB-pretreated leaves. MSB-mediated disease suppressions were found in cotyledons and different positions (1st to 5th) of true leaves inoculated with the lower conidial suspension, but only 1st to 3rd true leaves showed decreases in lesion sizes by the higher inoculum density. Increasing MSB-pretreatment times more efficiently decreased the lesion size by the higher disease pressure. MSB led to inducible expressions of defence-related genes SlPR1a, SlPR1b, SlPIN2, SlACO1, SlChi3, and SlChi9 in tomato leaves prior to B. cinerea infection. These results suggest that MSB pretreatment can be a promising alternative to chemical fungicides for environment-friendly management of tomato grey mould.

• Applied Microscopy
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• 제24권4호
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• pp.115-122
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• 1994

A computer program has been developed to analyze easily the Kikuchi pattern which is useful in obtaining the crystallographic data of materials. This program can simulate the Kikuchi patterns for 14 Bravais lattice by using the matrix algebra. Convenient menu system was also added to enhance the applications of the program. That is, by varying the tilting angle, camera length (RADIUS) and $S_{max}$ in the menu, various Kikuchi patterns can be obtained. The simulated patterns, then, can be compared with the experimentally-obtained Kikuchi pattern to examine validity of simulation.

• 대한원격탐사학회지
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• 제38권3호
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• pp.299-309
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• 2022

최근 한반도 주역 해역의 수온이 꾸준히 증가하고 있다. 수온변화는 어업생태계에 영향을 미칠 뿐만 아니라 해양에서의 군사작전과도 밀접히 연관되어 있다. 본 연구는 딥러닝 기술을 기반으로 하는 다양한 예측모델을 통해 단기간 수온예측을 시도함으로써 어떠한 모델이 수온예측분야에 더욱 적합한지를 제시하는 것에 목적을 두었다. 예측을 위해 사용한 데이터는 국립수산과학원에서 해양 관측부이를 통해 관측한 2016년부터 2020년까지 동해 지역(고성, 양양, 강릉, 영덕)의 수온 데이터이다. 또한 예측을 위한 모델로는 시계열 데이터 예측에 우수한 성능을 보이는 Long Short-Term Memory (LSTM), Bidirectional LSTM 그리고 Gated Recurrent Unit (GRU) 기법을 사용하였다. 기존 연구가 LSTM만을 활용하였던데 반해 이번 연구에서는 LSTM 외에 다양한 기법을 적용함으로써 각 기법의 예측 정확도와 수행시간을 비교하였다. 연구결과, 1시간 예측을 기준으로 모든 관측지점에서 Bidirectional LSTM과 GRU 기법이 실제값과 예측값의 오차가 가장 적은 것으로 확인되었으며, 학습시간에 있어서는 GRU가 가장 빠른 것으로 확인되었다. 이를 통해, 예측 오차를 줄이면서 정확도를 향상하기 위한 수온예측에는 Bidirectional LSTM을 활용하고 대잠작전처럼 정확도 외에 실시간 예측이 필요한 분야에 있어서는 GRU 기법을 활용하는 방안이 더욱 적절할 것으로 판단된다.

• 전자공학회논문지A
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• 제32A권2호
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• pp.89-95
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• 1995

The structure of boron ion-implanted pn junctio in the vacancy-doped p-type HgCdTe was investigated with the differential Hall measurement. The as-implanted junction showed the electron concentration as high as 1${\times}10^{18}/cm^{3}$ and the junction depth of 0.6.mu.m. When the HgCdTe junction was heated in oven, the electron concentration near the junction decreased and the junction depth increased as the annealing temperature and time increased. The junction structure after the thermal annealing was n$^{+}$/n$^{-}$/p. For the 200.deg. C 20min annealed sample, the electron mobility was 10$^{4}cm^{2}/V{\cdot}$s near the surface(n$^{+}$), and was larger thatn 10$^{5}cm^{2}/V{\cdot}$s near the junction(n$^{+}$). The junction formation mechanism is conjectured as follows. When HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms HgCdTe is ion-implanted, the ion energy generates crystal defecis and displaced Hg atoms near the surface. The displaced Hg vacancies diffuse in easily by the thernal treatment and a fill the Hg vacancies in the p-HgCdTe substrate. With the Hg vacancies filled completely, the GfCdTe substrate becomes n-type because of the residual n-type impurity which was added during the wafer growing. Therefore, the n$^{+}$/n$^{-}$/p regions are formed by crystal defects, residual impurities, and Hg vacancies, respectively.

• Corrosion Science and Technology
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• 제15권4호
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• pp.159-165
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• 2016

An attempt has been made to understand the influence of retrogression and re-aging (RRA) on the exfoliation corrosion behaviour of AA 7085 alloy in comparison with the peak aged condition (PA). Immersion tests using ASTM G34 and studies involving electrochemical impedance spectroscopy showed that the RRA treated alloy provided higher resistance to exfoliation corrosion than the PA treated alloy. The improved resistance was attributed to the enhanced Cu content and the discontinuous nature of the grain boundary precipitate, which was revealed through transmission electron microscopy.

• 한국군사과학기술학회지
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• 제11권2호
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• pp.16-22
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• 2008

So far, Korean command post vehicles(CPs) have used voice-only radio communication among the mechanized troop units such MBTs and IFVs, etc. But digital data communication technology should be introduced to improve mission success capabilities and accommodate integrated combat capabilities through increasing SA(situation Awareness), or spatiotemporal synchronization of military operation in battle field environment. Therefore, conventional CPs, which have been operated without digital network, urgently needs to mount a battle management system which furnish with tactical information network, considering that korean new MBTs or new IFVs will be fielded soon. This study suggests some performance enhancement method which might be applicable to CPs which have a role of connecting Battalion unit to Brigade C4I system.

• 한국군사과학기술학회지
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• 제17권4호
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• pp.471-478
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• 2014

Navy forces of ROK asked for more than 90% operational availability in the requirement document of combat ship. This study proposes the evaluation methodology of operational availability with the evaluation process, calculation formula, analysis of operational test data. As the case study, the developed methodology is proved to apply for 00 batch-I naval ship using the data to be acquired during the operational test period. The operational availability by test data was 90.03%, and it was satisfied with objective value 90%. The paper will contribute not only to establish the evaluation methodology of operational availability for combat ship but also other general weapon system.

• Journal of the Korean Data and Information Science Society
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• 제23권5호
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• pp.961-970
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• 2012

국방연구개발에 참여하는 업체 중에 특정기술을 일정기간에 개발할 수 있는 역량을 구비한 업체를 선정하기 위해서는 사업목적에 적합한 평가지표를 개발하는 것이 매우 중요하다. 본 연구는 선행연구와 국방 연구개발의 특성, 현재 사용하고 있는 항목을 종합하여 새로운 지표를 개발하고 전문가 인터뷰를 통해 객관화 하였다. 선정항목의 타당성 검증과 계층구조 모형설계를 위해 주축요인분석을 실시하였으며 27개 변수 중 타당성이 없는 10개를 제외하고 17개 변수를 최종 선정하였다. 17개 변수는 계층분석법 (analytic hierarchy process)을 통해 평가지표 항목의 가중치를 부여하였으며, 상위계층에서는 업체능력이 개발계획보다 중요하게 나타났고, 하위계층에서는 고객과의 의사소통 및 협력방안과 현 사업 유사기술 특허 및 논문의 우수성, 소요기술 확보현황 등이 높은 순위로 나타났다. 반면 기술유출 방지대책, 협력업체 전문성 및 관리의 적절성, 소프트웨어 개발방안 등은 낮은 순위로 나타났다.