• Title/Summary/Keyword: Accelerated Aging

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Transition Temperature Evaluation of 1Cr-1Mo-0.25V Steel Using Miniaturized Charpy Impact Specimen (소형 샤르피 충격시험편을 이용한 1Cr-1Mo-0.25V강의 천이온도 평가)

  • Nahm Seung Hoon;Kim Si Cheon;Lee Hae Moo
    • Journal of the Korean Institute of Gas
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    • v.2 no.4
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    • pp.42-46
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    • 1998
  • Miniaturized specimen technology Permits mechanical behavior to be determined using a minimum volume of material. The technology is useful in case of not collecting a large amount of materials from industrial equipments. Five kinds of accelerated degradation materials were prepared by isothermal aging heat treatment at $630^{\circ}C$. Three kinds of specimens were prepared for impact testing. In order to increase plastic constraint of subsize specimen, side-groove was introduced. Results between subsize and full size impact testing were compared. Size effects correlations were developed for the impact properties of turbine rotor material. These correlations successfully predict the ductile brittle transition temperature (DBTT) of full size Charpy impact specimens based on subsize specimen data.

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A case of Werner Syndrome Complicated by Bone Metastasis of Rhabdomyosarcoma (횡문근육종의 골전이가 동반된 워너증후군 1례)

  • Song, Joon-Hwan;Sun, Dong-Shin;Kim, Ho;Lee, Yoon-Hee;Hong, Yong-Hee;Lee, Dong-Hwan
    • Journal of Genetic Medicine
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    • v.6 no.1
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    • pp.91-94
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    • 2009
  • Werner syndrome (WRN), or adult progeria, is a very rare, autosomal recessive disorder characterized by the appearance of accelerated aging, including cataracts, gray hair, skin atrophy, and atherosclerosis. This syndrome is caused by mutations in the WRN gene and had a high risk of a spectrum of rare neoplasms including: i) non-epithelial malignant or pre-malignant tumors/conditions, osteosarcomas and soft tissue sarcomas, malignant melanomas, myeloid leukemia and myelodysplastic syndrome; ii) an epithelial neoplasm, thyroid carcinoma, and iii) meningiomas. Recently, authors experienced a case of Werner syndrome complicated by bone metastasis of rhabdomyosarcoma in a 20-year old Korean man. The patient revealed a painful mass on his right knee and progeroid features, short stature, scalp alopecia, abnormal dentition, craniofacial disproportion, hypothyroidsm, cataracts and osteoporosis. The onset of symptoms of Werner syndrome generally precedes any later symptoms of associated conditions, such as malignant tumor. Therefore, early recognition of Werner syndrome is important to assist identification of malignant tumors at an early stage in this patient group.

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A Presevatived Study On Accelerated Aging Of The System Of Mass-Deacidification In Domestic (인공열화에 의한 국산 대량탈산시스템의 보존성 연구)

  • Shin, Jong-Soon
    • Journal of Korean Society of Archives and Records Management
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    • v.1 no.1
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    • pp.177-200
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    • 2001
  • The causes which affects the deterioation of paper arc paper structure, papermaking process, temperature and rative humidity, light and biological agents. Paper made from cllulose fibers by the wood and the nonwood, This paper structure is further hydrolyzed by acidic additive such as the sizing agents during the manufacturing process. These additives leave residual acids in the paper, which break the cellulose clown to simper molecules. The results is weak paper and bas caused most of the damage to book. This study was carried out to investigate the presevation and the deacidification for the permanenece by the book. The deacidification and the chemical agents aims to nutralized the aicd in paper and add alkaline to it as a buffer to withstand future acid attacks. By applying the system to the acid paper with a pH of 4.5 neutralized a pH of 8.5. The expected of alkaline reserved paper extend about 2times and 3times than acidic paper.

Characteristics of inorganic nutrient absorption of potato (Solanum tuberosum L.) plants grown under drought condition

  • Bak, Gyeryeong;Lee, Gyejun;Kim, Taeyoung;Lee, Yonggyu;Kim, Juil;Ji, Samnyeo
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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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.

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Deterioration Characteristics and an On-Line Diagnostic Equipment for Surge Protective Devices (서지 보호기의 열화 특성과 온라인 진단장치)

  • Park, Kyoung-Soo;Wang, Guoming;Hwang, Seong-Cheol;Kim, Sun-Jae;Kil, Gyung-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.10
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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%.

Effect of Rapid Chilling on Beef Quality and Cytoskeletal Protein Degradation in M. longissimus of Chinese Yellow Crossbred Bulls

  • Mao, Yanwei;Zhang, Yimin;Liang, Rongrong;Ren, Lulu;Zhu, He;Li, Ke;Zhu, Lixian;Luo, Xin
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.8
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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.

Behavior of Elastic and Plastic Limit Loads of Thinned Elbows Observed During Real-Scale Failure Test Under Combined Load (감육엘보 실증실험에서의 탄성 및 소성 한계하중 거동 고찰)

  • Lee, Sung-Ho;Lee, Jeong-Keun;Park, Chi-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.9
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    • pp.1293-1298
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    • 2010
  • In most power plants, wall thinning in carbon-steel pipes due to flow-accelerated corrosion is one of the major aging phenomena, and it reduces the load-carrying capacity of the piping system. Various types of wall-thinning defects were manufactured in real-scale elbows, and monotonic in-plane bending tests were performed under internal pressure to evaluate the failure behavior of the elbows. In this paper, the behavior of elastic and plastic limit leads of locally thinned elbows in a real-scale failure test is presented. The loads determined on the basis of TES (twice elastic slope) were considered to be the limit loads of locally thinned elbows so that the integrity of the thinned elbows could be maintained, even when a small amount of plastic deformation might have occurred.

Characteristics of Starch Paste for Conservation of Paper Properties (Part 1) - The Nature and Adhesive Strength of Starch Paste - (지류 문화재 보존처리용 전분계 풀의 특성 (제1보) - 전분의 종류에 따른 접착 특성 -)

  • Yang, Eun-Jung;Cho, Kyoung-Sil;Choi, Tae-Ho
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.45 no.4
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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.

Microstructural Evolution of X20CrMoV12.1 Steel upon Short-term Creep Rupture Test

  • Hino, Mariko;He, Yinsheng;Li, Kejian;Chang, Jungchel;Shin, Keesam
    • Applied Microscopy
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    • v.43 no.4
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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.

Development of Extra High Voltage(400kN) Porcelain Insulator for Transmission Lines (765 kV용 400 kN 현수애자 개발)

  • 최인혁;최장현;이동일;최연규
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.8
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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.