SUS 304鋼의 크리이프溫度領域에 관한 時間依存型 및 싸이클依存型 疲勞크랙 傳播

周原植 동아대학교 공과대학 부설 한국자원개발연구소 1984 硏究報告 Vol.8 No.1

The low-cycle fatigue creak growth behavior of SUS 304 Stainless steel was investigated at 650℃ by the nonlinear fracture mechanics. Crack Propagation can be separated into cycle-dependent and time-dependent, the former is correlated with △J_(f), J-intergral range and the latter is correlated with J', modified J integral. Transition from cycle-dependent to time-dependent crack growth was successfully predicted using the β hypothesis, which was proposed by the authors on the basis of an analysis on the interaction of elastic and creep strain. To investigate the reliability of β-hypothesis, experimenting by the change of stress-level, stress rate and frequency, following conclusions were obtained. 1) High temperature fatigue crack propagation was separated into cycle-dependent and time-dependent. 2) Transition of crack propagation was predicted by △J_(c)/△J_(f) or β. 3) Lower limit in cycle-dependent crack propagation was obtained.

조류생산잠재력에 의한 진양호의 생물학적 수질평가

주현수,김진,박종천,정원석,이원교,이우범 國立 麗水大學校 環境問題硏究所 2000 環境硏究論文集 Vol.3 No.-

On filtrated and autoclaved water samples from Lake Jinyang, algal growth potential(AGP) test using Selenastrum capricornutum Printz were performed from February, 1999 to October, 1999 in order to assess fertility potential of the lake and to identify possible limiting nutrients. Algal growth potentials of the filtrated and filtrated after autoclaved samples were 0.018 ㎎/ℓ ~9.965 ㎎/ℓ and 0.018 ㎎/ℓ ~28.788㎎/ℓ respectively during surveyed period. AGP of the filtrated after autoclaved were higher than those of the filtrated only except some specific stations. The points of maximum growth were measured after addition of N, P and unenriched samples (control). The limiting factor was nitrogen only at site 5 in spring and phosphate appeared to be the major limiting nutrients in spike test throughout the year, especially during spring and autumn. Accoding to trophic level by Sudo(1980), the water quality of lake Jinyang were estimated mesotrophic at site 2, 4, 5, 6 in spring, at site 3, 6 in summer and at site 6 in autumn but all other sites were oligotrophic. But it is suggested that if we have not manigement of lake Jinyang, the water quality is possible to convert eutrophic.

SA 508c-3강의 고온에서 J-R 및 Tmat의 평가

주원식,임만배 東亞大學校 1998 東亞論叢 Vol.35 No.-

In this study, the J-Resistance Curve and material tearing modulus of SA508-C3 steel, which is one of the used nuclear pressure vessel steel, were measured at room temperature, 200℃ and 300℃ according to load ratio analysis and ASTM E813. ASTM E1152, respectively. It was observed that J-R curve and Tmat value decreased as the temperature level invreased. Applicability of Tj proposed by Paris et al as an instability paramter for ductile material is investigated. The results are the Tj parameter may be used as a crack instability parameter.

SUS 304강의 크리이프 온도역에 있어서 피로균열성장거동에 관한 연구

주원식,조석수 동아대학교 공과대학 부설 한국자원개발연구소 1993 硏究報告 Vol.17 No.2

The high temperature fatigue crack growth behavior of Type SUS 304 stainless steel at 550℃ and 650℃ was investigated under various kinds of stress ratios and frequencies in sinusoidal waveform. The result arranging crack growth rate by modified J-integral J' showed influence of stress ratio and frequency. All the data obtained under the test at 550℃ were plotted within data band of da/dN-△J_(f) relationship. Both the time and the cycle dependent crack growth behavior were observed under loading conditions at 650℃, but the cycle dependent crack growth behavior predominantly appeared and the time dependent crack growth behavior was little observed under loading conditions at 550℃. Fractographic examinations for fracture surface indicated that the fracture mode was generally transgranular. The J'_(an) had a validity in case of 650℃, but had scarcely it in case of 550℃

섬진강 식물플랑크톤 군집의 계절변화

주현수,김진,이원교,이우범 國立 麗水大學校 환경문제硏究所 2001 環境硏究論文集 Vol.4 No.-

A survey of phytoplankton community was carried out seasonally from January to September, 2000 at Seomjin river, Jeollanamdo, Korea. The author have examined 158 taxa of the phytoplankton from researched area. These were composed of 6 classes, 14 orders, 33 families, 75 genera, 145 species, and 13 varieties. The composition of occurrence species were as follows: green algae are 42.4%, diatoms are 39.2%, blue green algae are 12.0% and etx(6.4%). Dominant species were Scenedesmus dimorphus, Melosira varians, M,granulata, Fragilaria constuns, Asterionella grasillima, Synedra ulna, Synedra acus, Cymbella affinis, Nitzschia sigma, N.seriata, frustual. The standing crops varied from 2.304 cell/ℓ to 13.056 cells/ℓ in winter and spring, and appeared from 234 cells/ℓ to 6784cell/ℓ in summer and autumn. It was different than general dimictic lake in temperate zone has seasonal change of standing crop. Phytoplankton density of Seomjin river were lower about ten times to a five thousand tines than those of other lakes and river in Korea. So, to preserve the water quality in Seonjin river we have to manage continuously on the nitrogen and phosphorus.

오원천의 식물플랑크톤 군집에 대한 연구

주현수,김진,박종천,정원석,송현철,이용탁,이우범 國立麗水大學校 環境問題硏究所 2004 環境硏究論文集 Vol.6 No.-

We carried out a study on phytoplankton community at Owon stream, Jeollabukdo, Korea. The author have examined 83 taxa of the phytoplankton from researched area. These were composed of 5 classes, 11 orders, 21 families, 44 genera, 79 species, and 9 varieties. The composition of occurrence species were as follows: green algae are 48.2%, diatoms are 33.7%, blue green algae are 10.8% and etc(7.3%). Dominant species were Chlamydomonas angulosa, Pandorina morum, Coelastrum microporum, Scenedesmus quadricauda, Staurastrum gracile, Melosira varians, Me. italica, Synedra ulna, Sy. acus, Cocconeis placentula, and Cymbella tumida. The standing crops varied from 1,650cells/ℓ to 47,000cells/ℓ. Phytoplankton density of Owon stream were lower about 8.6 times to a 1,531 times than those of other lakes and rivers in Korea. So, to preserve the water quality in Owon stream we have to manage continuously on the nitrogen and phosphorus.

증후성 단독 중뇌동맥협착의 예후

이수주,이광호,정진상,조수진,이원용,이한보 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

154Gd의 감마-감마 각 상관관계 측정

朱寬植,鄭元謨 明知大學校 自然科學硏究所 1984 자연과학논문집 Vol.2 No.-

?Gd의 몇몇 감마전이에 대한 혼합비 δ를 구하기 위하여 감마-감마 각 상관관계 실험을 하였다. 두개의 Single Channel Analyzer 와 세개의 Counter, 그리고 하나의 Univeral Coincidence 를 사용한 동시회로가 본 실험에 사용되었다. 각 상관계수 Akk를 구하기 위하여, 각도 90?, 120?, 150?180?에서 동시계열(1596-123 keV, 1274-123keV,1005-123keV,873-123keV,248-123keV,723-873keV)을 조사하였다. δ(1596)=-0.091?, δ(1274)=-0.0009? δ(1005)= 6.3?, δ(873) =-5.9?, δ(248)= 0.295?를 구하였다. Gama-gamma angular correlation measurements were perormed to determine the mixing ratio δof some γ-transistions in ?Gd. The coincidence circuit with two single channel analyzer, three counters and a universal coincidence were used to this experiment. To get the angular correlation coefficient Akk, the angular correlation function W(Θ) was fitted to the coincidence sequences at the angular positions Θ=90?, 120?150?and 180?. Results for themixing ratios are: δ(1596)=-0.091+0.049-0.052, δ(1274)=-0.009+0.016-0.034, δ(1005)=6.3+4.5-1.8, δ(873)=-5.9+2.5-1.8, δ(248)=0.295+0.070-1.134

高溫低싸이클 疲勞크랙전파에 미치는 過度的 크리이프變形擧動의 影響

周原植,韓根祚 동아대학교 공과대학 부설 한국자원개발연구소 1985 硏究報告 Vol.9 No.1

Considering the elastic strain and the creep strain at high temperature low cycle fatigue, together, we could find that the experimental modified J integral, J'ex is larger than the theoretical value, J'a. To investigate which effects this enlargement have on the crack propagation in the creep-fatigue interaction range, the high temperature low cycle fatigue crack experiment was accomplished using CN specimens. The results are as follows. 1. The enlargement of J'ex is not considerable at R=0 but at R=-1 it is considerable. 2. J'ex with low stress holding time is 2-10 times larger than the one without holding time. 3. In case of no holding time, the enlargement of J'ex has effects on the crack crack propagation rate at R=-1, but at R=0 a certain factor having no effects was found out.

현훈 환자 Neuron Specific Enolase의 임상적 의의

김원주,김선곤,유철형,김원찬,김용덕,최영철,이명식 대한신경과학회 1998 대한신경과학회지 Vol.16 No.4