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정희돈 대한기계학회 1994 大韓機械學會誌 Vol.34 No.1
AE는 여러 분야에서 응용되어 보다 가치높은 정보를 얻을 수 있는 기법이다. 금속재료를 위주로 했던 초기에 비해 요즈음은 신소재와 지하에너지의 개발 그리고 산업체에서의 생산성 향상을 위한 적용에까지 그의 응용 범위가 넓어져 가고 있음을 알 수 있다. 또한 AE는 고체 재료의 변형 및 파손에 관한 정보뿐만 아니라, 의료진단 수법으로서의 개발은 물론, 기체 및 액체에서 발생하는 각종 물리적 현상의 이해에도 응용될 수 있는 등, 앞으로도 그의 응용범위는 노력 여 하에 따라 더욱 넓어지고 종래의 평가 방법으로는 기대하기 어려웠던 많은 정보들을 제공하게 될 이다.
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정희돈 한국작물보호협회 1986 자연과 농업 Vol.7 No.6
작물을 시설내에서 재배한다는 것은 재배환경을 외부와 인위적으로 차단한 상태에서 집약관리를 하는 것으로 뜻하지 않은 생리장해가 발생하기 쉽다. 일반적으로 생리장해의 발현증상은 자칫하면 병$\cdot$해충의 증상으로 오인하여 경제적 손실을 입기 쉬운데 겨울철 시설원예에서 발생하기 쉬운 생리장해의 원인과 대책에 대하여 알아본다.
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2.25Cr-1Mo 강의 열화와 기계적 성질변화에 관한 연구
정희돈,Jeong, Hee-Don 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.5
As recieved boiler tuve steel was aged artificially at $650^{\circ}C$ and$690^{\circ}C$ for various time duration to simulate the material deterioration which could be occurred during the operation of fossiol power plants. And the tensile tests, the microhardness tests and the characterization of carbides formed in the aging process were performed to asses the relationship between the mechanical properties and the effect of thermal aging. Furthernore, the amout of Mo-rich carbide were investigated by ondestructive method by noticing the fact that formation of Mo-rich carbide were investigated by ondestructive melthod by noticing the fact that formation of Mo-rich carbides($Mo_6C$) which stabilizes lastly affects the mechanical properties. It was known that the microhardness results of service exposed materials were similar to the ones which are aged at $650^{\circ}C$. The room temperature measurement showed small variation in the yield points and ultimate strength in materials aged at $650^{\circ}C$. Those properties at $540^{\circ}C$ showed the abrupt decrease compared with as received material even if short aging time. And it was found that $650^{\circ}C$ $690^{\circ}C$ aging cause different effects on mechanical properties, although the temperature time parameters(LMP;Larson-Miller parameter) are same. And it was concluded that the aigng at $650^{\circ}C$ is more appropriate to simulate the service exposed condition. Finally, the relationship between high temperature tensile properties and Ip values were established, which offers a potential way of reliability tests onthe power plant components.
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정희돈 대한기계학회 1991 大韓機械學會誌 Vol.31 No.3
발전 설비를 중심으로 고온 부재의 잔존 수명 진단을 위한 경년 열화도의 측정에 관련된 연구 현황에 대해 극히 좁은 범위 안에서 개략적으로 기술했다. 국내의 산업체에서도 현재 이에 관 련된 문제점을 제시하고 있고 앞으로 이러한 문제의 발생은 그 빈도와 규모면에서 증가하게 될 것이다. 이에 대비하여 기존 방법의 기술적 터득과 데이터의 축적 그리고 측정 정도를 향상시 키기 위한 새로운 측정 방법들의 개발이 시급한 실정이다. 정확한 진단과 수명이 예측을 위해선 본 글에서 설명된 각종 측정법들과, 짧은 식견으로 여기에서는 설명되지 못한 금속학적 고찰을 가미한 수많은 측정법들을 종합적으로 행하여야 할 필요가 있다는 것은 말 할 나위도 없다. 또한 실기 사용 부재의 입수, 나름대로의 정보 교환은 연구 초기 단계에서 부딪치는 수많은 문 제점들을 원활하게 해결하기 위해서는 각 전문분야의 학술적 교류와 더불어 산. 학. 연의 공동 연구가 절실하게 요구된다.
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鄭凞敦,尹善柱,金秉烈 영남대학교 자원문제연구소 1991 資源問題硏究 Vol.10 No.-
Leaf growh patterns were compared in the different head shaped chinese cabbages, “Bokdor”(ovata type) and “Cheongsan” (cylindrica type). Many more expanded leaves were observed in "Bokdori" as compared with the "Cheongsan". "Cheongsan" was much higher in head height, but "Bokdori" was bigger in head width. Although no difference was observed in trimmed head weight (except the wrapper leaves) between the varieties, each leaf fresh weight was heavier in "Cheongsan." We also observed the double peaks of maximum growth rate through the growing period. Leaf height, leaf width and midrib were similar growth patterns, however "Cheongsan's" growth rate was more rapid than "Bokdori". Leaf index (leaf length/leaf width was similar through the growing season in "Bokdori" , whereas continuously increased to the 35th leaf in "Cheongsan". "Cheongsan", sylindrica type, was observed very rapid growth rate in early growing period but rapidly decreased in late growing period compared with the "Bokdori" , ovata type.
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鄭凞敦,尹善柱,金秉烈 영남대학교 자원문제연구소 1992 資源問題硏究 Vol.11 No.-
This experiment was conducted to get the basic data for the optimum fruit harvesting time by investigation of the seasonal content changes caused by fruit growth pattern and days after anthesis in summer cucumber cultivars (Cucumis sativus L. cvs. , "Shinhukjiniu" and"Hukkwangjinju"). Fruit growth was rapidly increased as early as 8 days after anthesis for both cultivars. The growth rate in fruit length was gradually decreased to the blossom end than the upper part (peduncle) of the fruit, Chlorophyll content was maximum at 5 days after anthesis in "Shinhukjinju", whereas continuous increased upto 7 days in "Hukkwangjiniu". Fructose and glucose also observed maximum at 6 days after anthesis in "Shinhukjinju", but increased upto 7 days in "Hukkwangjinju". Sucrose have a tendency to decline through the fruit growth. Ascorbic acid content was decreased after anthesis. In weight loss during the storage, continuous decrease was observed in the earlier harvested fruits than the late ones when stored in room temperature, whereas least weight loss rate was observed in harvested fruit at 7 days after anthesis when stored at 6t, In both cultivars, the best fruit quality was obtained when harvested at 7 days after anthesis.
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Maleic Hydrazide 處理時期가 감자 品種別 萌芽抑制 및 貯藏期間中 重量減少에 미치는 영향
鄭凞敦,金貞淑,李昌垠 영남대학교 자원문제연구소 1985 資源問題硏究 Vol.4 No.-
The effectiveness of maleic hydrazide(MH) on sprout inhibition and storage life of potato tubers during storage was examined with three cultivars(cv), Irish Cobbler, Dejima and Shimabara. Solution of 0.2% MH was applied at 7, 14 or 21 days before harvest to the whole plant. The number of potato tubers and tuher weight per plant were not influenced by applic-ation of MH, but Dejima cv. showed decreasing tendency. Sprout growth was hardly seen from MH treated tubers. Weight loss of tubers during storage were markedly reduced by MH treatment regardless of the application time and cvs. In Shimabara cv., the rot percentage was higher in early MH treated tubers than that of the late application or untreated ones.
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