• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 추계학술대회 논문집
• /
• pp.139-141
• /
• 2007

Compression tests were carried out to investigate morphologies of compressed specimen, deformation microstructure and stress-strain relation in high-nitrogen austenite stainless steel. Tests were performed under a wide range of temperature and, with true strain rates up to $\dot{\varepsilon}$ =0.05, 0.1, 0.5 and $1.0s^{-1}$. The activation energy of loading force was equal to plastic deformation energy within the temperature range of $900^{\circ}C$ to $1250^{\circ}C$. Dynamically recrystallized grain size decreased with an increasing strain rate and temperature. Flow stresses and deformation microstructures, were used to quantify the critical strain rate and recrystallized grain size. The grain size versus strain rate-temperature map obtained in the study was in good agreement with the deformation microstructures of compressed specimens.

• Journal of applied mathematics & informatics
• /
• 제23권1_2호
• /
• pp.353-359
• /
• 2007

A necessary and sufficient condition for Demyanov difference and Minkowski difference of compact convex subsets in $R^2$ being equal is given in this paper. Several examples are computed by Matlab to test our result. The necessary and sufficient condition makes us to compute Clarke subdifferential by quasidifferential for a special of Lipschitz functions.

• 대한전자공학회논문지
• /
• 제15권5호
• /
• pp.34-38
• /
• 1978

rate equation을 사용하여 DH Laser Diode에서 나타나는 전기적 포화현상이 이론적으로 설명되었다. Carrier density는 threshold 이후에 서서히 ns에 접근해가며 이론적으로 계산된 곡선과 예측된 ΔVj는 전에 보고된 실험결과를 정확히 설명한 수 있음이 입증되었다. carrier saturation factor kβ를 제안하였으며 kβ는 L.D의 이상성을 결정하는 중요한 factor 임이 설명되었다. kβ와 β와의 관계를 통해 β가 작으면 작을수록 diode의 특성은 이상적 diode에 가까와짐이 밟혀졌다.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 1995년도 추계학술대회 학술발표 논문집
• /
• pp.40-44
• /
• 1995

In this paper, we propose a retrieval system using knowledges of database expressed linguistically, where the relation between data are constructed by FCM. Several algorithms have been proposed to solve the major problem in the conventional retrieval system that the system doesn't reply in case of no data equal to user's query, and to express knowledge of database linguistically. This paper proposes the improved method of adding new cluster and the method of retrieving database from user's query. The validity of this retrieval system is shown by applying its algorithm to an example : the mail order service in post office.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2009년도 춘계학술대회 논문집
• /
• pp.67-71
• /
• 2009

본 논문에서는 우리나라에서 동일한 환경에 설치되어 있는 247.5kW bulk형 모듈과 a-Si형 모듈의 6월 발전량을 조사 분석하여 기상조건(일조량, 평균기온, 강수량, 운량, 풍속 등)과의 관계를 분석하고 최근 지구온난화 등으로 인한 기후변화에 따라 보다 고효율적인 모듈 산정방안을 제시하였다.

• 조명전기설비학회논문지
• /
• 제23권12호
• /
• pp.75-82
• /
• 2009

본 논문에서는 우리나라에서 동일한 환경에 설치되어 있는 247.5[kW] bulk형 모듈과 a-Si형 모듈의 6월 발전량을 조사 분석하여 기상조건(일조량, 평균기온, 강수량, 운량, 풍속 등)과의 관계를 분석하고 최근 지구온난화 등으로 인한 기후변화에 따라 보다 고효율적인 모듈 산정방안을 제시하였다.

• 설비공학논문집
• /
• 제11권5호
• /
• pp.642-646
• /
• 1999

Factors governing the rate of heat exchange comprise the air temperature, the speed of air movement, relative humidity, and relation indoors. Recently, there are many researches on the transient analysis of indoor environmental factors such as the dry bulb temperature, relative humidity and air velocity in miniature models. The purpose of this study is to measure the environmental factors and to analyze and evaluate the characteristics of indoor environment with the different envelope structures using a granite dome model. According to the variation of humidity, the state of interior relative humidity for clay model has an equal tendency, although a little range of variation is shown in comparison to the cement model.

• 대한수학회지
• /
• 제56권3호
• /
• pp.723-738
• /
• 2019

A property of reduced rings is proved in relation with centers, and our argument in this article is spread out based on this. It is also proved that the Wedderburn radical coincides with the set of all nilpotents in symmetric-over-center rings, implying that the Jacobson radical, all nilradicals, and the set of all nilpotents are equal in polynomial rings over symmetric-over-center rings. It is shown that reduced rings are reversible-over-center, and that given reversible-over-center rings, various sorts of reversible-over-center rings can be constructed. The structure of radicals in reversible-over-center and symmetric-over-center rings is also investigated.

• 대한수학회논문집
• /
• 제36권1호
• /
• pp.27-39
• /
• 2021

We discuss the condition that every nonzero right annihilator of an element contains a nonzero ideal, as a generalization of the insertion-of-factors-property. A ring with such condition is called right AP. We prove that a ring R is right AP if and only if Dn(R) is right AP for every n ≥ 2, where Dn(R) is the ring of n by n upper triangular matrices over R whose diagonals are equal. Properties of right AP rings are investigated in relation to nilradicals, prime factor rings and minimal order.

• 대한수학회지
• /
• 제59권1호
• /
• pp.105-127
• /
• 2022

It is known that the maximal invariant set of a continuous iterative dynamical system in a compact Hausdorff space is equal to the intersection of its forward image sets, which we will call the first minimal image set. In this article, we investigate the corresponding relation for a class of discontinuous self maps that are on the verge of continuity, or topologically almost continuous endomorphisms. We prove that the iterative dynamics of a topologically almost continuous endomorphisms yields a chain of minimal image sets that attains a unique transfinite length, which we call the maximal invariance order, as it stabilizes itself at the maximal invariant set. We prove the converse, too. Given ordinal number ξ, there exists a topologically almost continuous endomorphism f on a compact Hausdorff space X with the maximal invariance order ξ. We also discuss some further results regarding the maximal invariance order as more layers of topological restrictions are added.