• 한국가스학회지
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• 제2권4호
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• pp.42-46
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• 1998

소형 시험편 기술은 최소량의 재료를 사용하여 그 재료의 물리적인 거동을 특성화할 수 있기 때문에 산업설비로부터 많은 재료를 수집할 수 없는 경우에 유용한 방법이다. 본 연구에서 사용한 재료는 화력발전소 터빈로터 소재로 많이 사용되고 있는 1Cr-1Mo-0.25V강이었으며, $^630{\circ}C$에서 등온열화처리하여 5종류의 가속 열화 모사재를 만들었다. 충격시험에는 표준 시험편과 소형 시험편이 사용되었으며, 일부 소형 시험편에 소성 구속을 증가시키기 위해 측면흠을 만들어 넣었다. 표준 시험편과 소형 시험편의 충격특성을 비교하였으며 크기효과를 고찰하였고, 소형 시험편의 연성취성천이온도와 표준 시험편의 연성취성천이온도와의 상관관계를 만들었다. 따라서 소형 시험편의 충격시험결과로부터 표준 시험편의 충격특성을 추정하는 것이 가능하게 되었다.

• Journal of Genetic Medicine
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• 제6권1호
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• pp.91-94
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• 2009

저자들은 출생당시 특이소견 없었고, 유전질환의 가족력이 없는 20세 남자 환자에서 우측하지에 골전이가 동반된 횡문근 육종을 발견하고, 저신장, 탈모, 백내장, 치열이상, 골다공증, 갑상선기능저하증, 작은 손과 발, 사지는 가늘고 체간이 두터우며, 신체에 비해 큰 머리등 특이한 외모를 가진 워너증후군으로 진단한 1례를 경험하였기에 문헌 고찰과 함께 보고하고자 한다.

• 한국기록관리학회지
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• 제1권1호
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• pp.177-200
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• 2001

종이의 열화 원인은 종이의 구조, 제조공정의 내적인 요인과 온도, 습도, 빛 미생물 등에 의한 환경적 용인으로 종이는 열화를 받게 된다. 식물체를 주성분으로 제조된 종이는 제조공정에 도입된 산성 물질에 의해 쉽게 가수분해 되어 셀룰로오스를 저분자량으로 변화 시킴으로 강도 저하, 황변화를 인해 내구성이 약해져 훼손되므로 자료의 가치를 상실하게 된다. 본 연구는 도서의 산성화를 예방하고 보존수명을 연장하기 위한 탈산 처리제, 탈산 처리 장비의 국내개발을 통하여 그동안 산성화 된 도서의 훼손을 근본적으로 해결 가능하게 되었다. 본 장비의 약품의 특성은 현재 시급한 보존처리 대상물의 기록물의 주기적인 탈산처리를 실시하므로 산성화 예방 및 열화된 도서의 보존이 가능하다. 실험 결과 1회 탈산처리시 pH4.5(산성)에서 pH8.5(약알카리성)로 중화되므로 보존수명이 2-3배 연장 가능하였고 외국산 장비의 국산화로 처리 비용을 크게 줄일 수 있다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.181-181
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• 2017

Global warming and climate change have been one of the most important problems last 2 decades. Global warming is known to cause abnormal climate and influence ecology, food production and human health. According to climate change model global warming is causing expansion of drought and increase of evaporation. Therefore, securing water in agriculture has been an important issue for crop cultivation. As potato is susceptible to drought, water shortage generally results in decrease of yield and decrease of biomass. In this research, we investigated characteristics of inorganic nutrient absorption and growth of plants grown under drought condition. Plants were sampled in sites of Cheong-ju and Gangneung, where the severity of drought stress were different. During the growth period in Gangneung, total rainfall in 2016 decreased by 50% compared with those in last 5 years average. Especially, there was almost no rain in tuber enlargement period (from mid-May to mid-June). On the other hand, the total rainfall in of Cheong-ju was is similar to those in last 5 years average. Inorganic components including K, Ca and Mg and plant growth factors such as plant length, stem length, leaf area index and plant biomass were investigated. Tuber yields in both areas were investigated at harvest. Growth period of plants was is longer in Cheong-ju than that in Gangneung. Contents of all inorganic components were higher in plants grown in Cheong-ju than in Gangneung. The results were attributed to higher production of plant biomass in Cheong-ju. Considering the results, severe drought stress conditions in Gangneung accelerated plant aging and resulted in low plant growth. Although total yield was greatly reduced under drought stress the rate of commercial yield was is not significantly different with non-drought conditions.

• 한국전기전자재료학회논문지
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• 제29권10호
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• pp.635-640
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• 2016

This paper dealt with the deterioration characteristics and an on-line diagnosis equipment for SPDs (surge protective devices). An accelerated aging test was carried out using a $8/20{\mu}s$ standard lightning impulse current to analyze the changes of electrical characteristics and to propose the diagnostic parameters and the criterion for deterioration of ZnO varistor which is the core component of SPDs. Based on the experimental results, an on-line diagnosis equipment for SPD was fabricated, which can measure the total leakage current, reference and clamping voltage. The leakage current measurement circuit was designed using a low-noise amplifier and a clamp type ZCT. A linear controller, the leakage current measurement part and a HVDC were used in the measurement of reference voltage. The measurement circuit of clamping voltage consisted of a surge generator and a coupling circuit. In a calibration process, measurement error of the prototype equipment was less than 3%.

• Asian-Australasian Journal of Animal Sciences
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• 제25권8호
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• pp.1197-1204
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• 2012

The objective of this study was to investigate the effect of rapid chilling (RC) on beef quality and the degradation of cytoskeletal proteins. Twenty Chinese Yellow crossbred bulls were selected and randomly divided into two groups. RC and conventional chilling (CC) were applied to left and right sides of the carcasses respectively after slaughtering. To determine whether electrical stimulation (ES) treatment can alleviate the potential hazard of RC on meat quality, ES was applied to one group. The effects of RC and ES were determined by meat color, shear force and cytoskeletal protein degradation postmortem (PM). The results showed that RC decreased beef tenderness at 1 d and 3 d postmortem, but had no detrimental effect on meat color. Western blotting showed that RC decreased the degradation rate of desmin and troponin-T, but the effects weakened gradually as postmortem aging extended. Degradation rates of both desmin and troponin-T were accelerated by ES. The combination of RC and ES could improve beef color, accelerate degradation rate of cytoskeletal protein and improve beef tenderness.

• 대한기계학회논문집A
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• 제34권9호
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• pp.1293-1298
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• 2010

본 연구에서는 인공감육엘보에 대해 내압 및 굽힘의 복합하중을 작용시킨 실 배관 실증실험으로부터 생성한 회전각 대비 모멘트 곡선으로부터 감육결함 엘보에서 소성변형이 시작되는 1 배탄성구배법에 기초한 OES 탄성하중과 2 배탄성구배법에 기초한 TES 소성하중의 거동 및 상관관계를 살펴보았다. ASME 에서도 제시하고 있는 TES 소성하중은 균열손상에 따른 배관계통 구조 건전성 상실을 배제하면서도 지속사용을 허용할 수 있는 대체 관리 기준으로서 적합한 것으로 판단된다.

• 펄프종이기술
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• 제45권4호
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• pp.52-64
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• 2013

This study was carried out to investigate the characteristics of starch paste which was used for the conservation of paper properties. Three kinds of commercial corn starch and five kinds of fermented wheat starch were examined on the contents of amylose and amylopectin, shapes of particles, and viscosity and pH of paste. And adhesive strength on the drying, accelerated aging, and wetting treatments were measured. The contents of amylopectin of oxidized corn starch were higher those of cationic corn starch, unmodified corn starch, and fermented wheat flour. In case of fermented wheat flour, increasing of a fermentation period was resulted in increasing of amylopectin contents. The particle shapes of commercial corn starch showed with a uniform polygon, but fermented wheat flour showed with a mixture of small and large oval types. The viscosity of oxidized corn starch were very lower those of cationic corn starch and unmodified corn starch. And increasing of a fermentation period of wheat flour was resulted in increasing of viscosity. The pH of commercial corn starch were 3.6-7.5 and fermented wheat flour were 3.6-5.2. Through the examination on the nature and adhesive strength of starch paste, the oxidized corn starch 60 cps which is the name of products and wheat flour which had fermented for 5 years were considered that most suitable for conservation of paper properties.

• Applied Microscopy
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• 제43권4호
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• pp.164-172
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• 2013

In this work, microstructural and hardness evolution of the X20 steel upon short-term creep test ($550^{\circ}C$ to $650^{\circ}C$, $180^{\circ}C$ to 60 MPa) was studied by using scanning electron microscope, electron backscattered diffraction, and transmission electron microscope, microhardness tester. After creep rupture, gauge and grip part of the specimens were microstructurally analyzed. Creep at the $650^{\circ}C$/60 MPa resulted in a rupture at 1,460 hours with growth of lath width from 1.31 to $2.87{\mu}m$ and a grain growth with a more equiaxed feature. There is a close relationship between Microhardness and lath width. The formation and coarsening of Laves phase, which was observed up to $600^{\circ}C$ of creep temperature, was accelerated by the applied stress. Slight coarsening of the $M_{23}C_6$ was observed in the $550^{\circ}C$ and $600^{\circ}C$ crept or aged specimens. The coarsening of $M_{23}C_6$ depended on the temperature, where specimens crept at $650^{\circ}C$ showed higher growth rate. The microstructural evolution of X20 after short-term creep test was extensively discussed in relation to the long-term creep/aging test reported in literatures.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권8호
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• pp.348-353
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• 2003

This paper was the research of high voltage suspension insulator (400 [kN]) including pottery stone, feldspar, clay and alumina of 17 [wt%]. The slurry was fabricated after ball milling mixed raw materials. Green compacts were made by the extrusion of jiggering method and were sintered at 1300[$^{\circ}C$] for 50 [min.] in the tunnel kiln. The sintered density was reached to 97% of theoretical density, and the bending strength was 1658 [k $g_{f}$/$\textrm{cm}^2$] and hardness and fracture toughness which was measured by ICL( indentation crack length ) method were 1658 (kgf/$\textrm{cm}^2$) and 27.5 [Gpa], respectively. In measurement of tana and insulation break voltage of 400 (kN) porcelain, tan$\delta$ took some numerical value between 17${\times}$10$_{-3}$ and 61${\times}$10$_{-3}$ and insulation break voltage value was 19.9$\pm$1.4 [㎸/mm]. The test was performed to research whether the shape of pin affect a overvoltage break load or not As a consequence, when a pin was designed a pin diameter 51 [mm] with the bottom form of two-step constructed with straight in the suspension insulator, Insulator showed overvoltage break load 52 [ton] of the highest value and reflected a fine characteristic in aged deterioration test which is one of the accelerated aging test. Also it could be confirmed a fine characteristic through performing the test that electrical property of insulator was established correctly in accordance with IEC 60383-1 standards.s.