• Title/Summary/Keyword: Heat Accumulation

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Effects of Deformation Conditions on Microstructure Formation Behaviors in High Temperature Plane Strain Compressed AZ91 Magnesium Alloys (고온 평면변형된 AZ91 마그네슘 합금의 미세조직 및 집합조직의 형성거동)

  • Minho Hong;Yebin Ji;Jimin Yun;Kwonhoo Kim
    • Journal of the Korean Society for Heat Treatment
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    • v.37 no.2
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    • pp.66-72
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    • 2024
  • To investigate the effect of deformation condition on microstructure and texture formation behaviors of AZ91 magnesium alloy with three kinds of initial texure during high-temperature deformation, plane strain compression tests were carried out at high-temperature deformation conditions - temperature of 673 K~723 K, strain rate of 5 × 10-3s-1, up to a strain of -1.0. To clarify the texture formation behavior and crystal orientaion distribution, X-ray diffraction and EBSD measurement were conducted on mid-plane section of the specimens after electroltytic polishing. As a result of this study, it is found that the main component and the accumulation of pole density vary depending on initial texture and deformation caondition, and the formation and development basal texture components ({0001} <$10\bar{1}0$>) were observed regardless of the initial texure in all case of specimens.

Bis is Induced by Oxidative Stress via Activation of HSF1

  • Yoo, Hyung Jae;Im, Chang-Nim;Youn, Dong-Ye;Yun, Hye Hyeon;Lee, Jeong-Hwa
    • The Korean Journal of Physiology and Pharmacology
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    • v.18 no.5
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    • pp.403-409
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    • 2014
  • The Bis protein is known to be involved in a variety of cellular processes including apoptosis, migration, autophagy as well as protein quality control. Bis expression is induced in response to a number of types of stress, such as heat shock or a proteasome inhibitor via the activation of heat shock factor (HSF)1. We report herein that Bis expression is increased at the transcriptional level in HK-2 kidney tubular cells and A172 glioma cells by exposure to oxidative stress such as $H_2O_2$ treatment and oxygen-glucose deprivation, respectively. The pretreatment of HK-2 cells with N-acetyl cysteine, suppressed Bis induction. Furthermore, HSF1 silencing attenuated Bis expression that was induced by $H_2O_2$, accompanied by increase in reactive oxygen species (ROS) accumulation. Using a series of deletion constructs of the bis gene promoter, two putative heat shock elements located in the proximal region of the bis gene promoter were found to be essential for the constitutive expression is as well as the inducible expression of Bis. Taken together, our results indicate that oxidative stress induces Bis expression at the transcriptional levels via activation of HSF1, which might confer an expansion of antioxidant capacity against pro-oxidant milieu. However, the possible role of the other cis-element in the induction of Bis remains to be determined.

An Improved Method for Phenology Model Parameterization Using Sequential Optimization (순차적인 최적화 기법에 의한 생물계절모형 모수추정 방식 개선)

  • Yun, Kyungdahm;Kim, Soo-Hyung
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.16 no.4
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    • pp.304-308
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    • 2014
  • Accurate prediction of peak bloom dates (PBD) of flowering cherry trees is critical for organizing local cherry festivals and other associated cultural and economic activities. A two-step phenology model is commonly used for predicting flowering time depending on local temperatures as a result of two consecutive steps followed by chill and heat accumulations. However, an extensive computation requirement for parameter estimation has been a limitation for its practical use. We propose a sequential parameterization method by exploiting previously unused records of development stages. With an extra constraint formed by heat accumulation between two intervening stages, each parameter can then be solved sequentially in much shorter time than the brute-force method. The result was found to be almost identical to the previous solution known for cherry trees (Prunus ${\times}$ yedoensis) in the Tidal Basin, Washington D.C.

HyungSang Medical Approach to Detoxification (동의보감(東醫寶鑑) 해독 처방에 대한 형상의학적 고찰)

  • Kim, Jong-Won;Jeon, Soo-Hyung;Jung, Heung-Sik;Kang, Kyung-Hwa;Lee, In-Sun;Lee, Sang-Hoon;Kim, Kyu-Kon;Lee, Yong-Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.23 no.2
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    • pp.278-287
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    • 2009
  • Ji-San, the founder of HyungSang medicine, emphasized food intake and detoxification by stating, "Korean medicine begins with detoxification." Toxin accumulates in one's body unless the internal and external conditions stay in their harmony. The accumulation of toxin is also caused by western medication or one-sided diet, and detoxification should be considered in those cases. HwangRyunHaeDok-Tang reduces fire and heat, and the lesion is likely to locate in the upper body. BangPoongTongSung-San can be used for systemic disease. IkWoon-San also reduces fire and heat but mainly focuses on promoting urination. InSamPaeDok-San has an effect of curing the external symptoms of SangHan(傷寒), in addition to detoxification. SeoGakJiHwang-Tang, SoDok-Eum, and SeoGakSoDok-Eum can resolve the heat-toxin when it is located on the surface. SibJeonDaeBo-Tang enhances the detoxifying function of human body. GhamDu-Tang and JaGeum-Jung have a general effect on detoxification.

Assay of Heat Stable Enterotoxin Producing E. coli (내열성장독소 생산 대장균의 판정)

  • Chang, Woo-Hyun;Kim, Moon-Gyo;Choi, Myung-Sik;Yang, Nam-Ung;Ko, Kwang-Wook;Seo, Jung-Ki
    • The Journal of the Korean Society for Microbiology
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    • v.18 no.1
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    • pp.53-58
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    • 1983
  • Enterotoxigenic E. coli is one of causative agents of the infantile diarrhea and traveler's diarrhea. A modified infant mouse assay(IMA) was developed for the detection of heat stable enterotoxin (ST) of E. coli isolated from diarrheal and control infants and assay system was established with using enterotoxin producing reference strains. The supernatant of the 24 hour-shaking culture of E. coli in Casamino Acid Yeast Extract Salt Broth(CYES-2) was ingested orally into the 2-4 day old ICR mice. After the mice were kept at $25^{\circ}C$ for 4 hours, they were sacrificed and the gut weight body weight ratio(GW/BW) was taken as the index of fluid accumulation induced by heat stable enterotoxin of E. coli. The results obtained were as follows; 1. The GW/BW responses of IMA tested with enterotoxin reference strains of E. coli(E. coli O148H28:$ST^+LT^+$, E. coli $O78H^-:ST^+LT^+$, E. coli O15H11:$ST^-LT^+$, E. coli O1H7:$ST^-LT^-$) appeared ta be ST dose-dependent, and not LT-dependent. From the dose-response curve, $25{\mu}l$ of culture supernatant was determined as test amount of the IMA. 2. Frequency distribution of IMA result from 643 strain of E. coli showed normal distribution at low GW/BW ratio and dispersed pattern at high GW/BW ratio. The GW/BW ratios of $0.056{\pm}0.004(mean{\pm}SD)$ of normal distribution which distributed from 0.044 to 0.068(P<0.01) was considered as ST negative. Thus the GW/BW ratio above 0.069 could be regarded as ST positive.

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Literatural study on the cause of the Infantile Vomiting (소아구토(小兒嘔吐)의 병인병리(病因病理)에 관한 동서의학적(東西醫學的) 문헌적(文獻的) 고찰(考察))

  • Han, Jae Kyung;Yoo, Dong Yeol
    • Journal of Haehwa Medicine
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    • v.9 no.1
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    • pp.337-352
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    • 2000
  • According to the literatual study on the Infantile Vomiting since the publication of ${\ll}Hwangjenaekung{\gg}$, the results were as follows. 1. The causes of vomiting are classified into the following kind: external cause are the cold and heat, not external and internal are disorder of food and mood, internal are the dysfuntion of spleen, stomach, liver, kidney. 2. The Oriental Medical cause of Infantile Vomiting is disorder of food, intusion of outside evil, heat accumulation in the stomach, deficiency of stomach liquid, reverse flowing of Qi resulted from fear and being frightened. There are so many causes of Infantile Vomiting, but they are all related to the stomach. 3. The Western Medical cause of Infantile Vomiting are classified with the situation of stimulation, age, accompanied symptom. The main cause related with the age is inhalation of amniotic fluid, maternal blood, infectious disease, wrong lactation method, functional and organic abnormality. 4. The Infantile Vomiting is similar with the adults, but the spleen and stomach of infants is so feeble that the vomiting happens very easily. The reverse flowing of Qi resulted from fear and being frightened and disorder of food are the main cause in infants. 5. The cause of Infantile Vomiting between Oriental Medicine and Western's is so similar and both emphasized the function of spleen and stomach. But the comment on the external cause(cold, heat) and not internal & external cause(mood disorder) is a creative view of Oriental Medicine.

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Effect of Laser Processing Patterns on the Bonding Interface Quality during Laser Sintering of Magnesium Alloys with Zirconia (마그네슘 합금 표면의 지르코니아 분말 레이저 소결과정에서 조사 패턴이 접합 계면 품질에 미치는 영향)

  • Yoon, Sangwoo;Kim, Joohan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.2
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    • pp.51-57
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    • 2021
  • The quality of the ceramic sintered coating on a metal surface through laser surface treatment is affected by the laser irradiation pattern. Depending on the laser irradiation pattern, the amount of residual stress and heat applied or accumulated on the surface increases or decreases, affecting the thickness attained in the ceramic sintering area. When the heat energy accumulated in the sintering area is high, the ceramic and the metal alloy melt and sufficiently mix to form a homogeneous and thick bonding interface. In this study, the thermal energy accumulation in the region sintered with zirconia was controlled using four types of laser processing patterns. The thickness of the diffusion region is analyzed by laser-induced breakdown spectroscopy of Mg-ZrO2 generated by laser sintering zirconia powder on the magnesium alloy surface. On the basis of the analysis of the Mg and Zr present in the sintered region through LIBS, the effect of the irradiation pattern on the sintering quality is confirmed by comparing and analyzing the heat and mass transfer tendency of the diffusion layer and the degree of diffusion according to the irradiation pattern. The derived diffusion coefficients differed by up to 9.8 times for each laser scanning pattern.

Regulation of amyloid precursor protein processing by its KFERQ motif

  • Park, Ji-Seon;Kim, Dong-Hou;Yoon, Seung-Yong
    • BMB Reports
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    • v.49 no.6
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    • pp.337-343
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    • 2016
  • Understanding of trafficking, processing, and degradation mechanisms of amyloid precursor protein (APP) is important because APP can be processed to produce β-amyloid (Aβ), a key pathogenic molecule in Alzheimer's disease (AD). Here, we found that APP contains KFERQ motif at its C-terminus, a consensus sequence for chaperone-mediated autophagy (CMA) or microautophagy which are another types of autophagy for degradation of pathogenic molecules in neurodegenerative diseases. Deletion of KFERQ in APP increased C-terminal fragments (CTFs) and secreted N-terminal fragments of APP and kept it away from lysosomes. KFERQ deletion did not abolish the interaction of APP or its cleaved products with heat shock cognate protein 70 (Hsc70), a protein necessary for CMA or microautophagy. These findings suggest that KFERQ motif is important for normal processing and degradation of APP to preclude the accumulation of APP-CTFs although it may not be important for CMA or microautophagy.

Development of Motorcycle Brake Design Aided Program for Thermal Analysis (모터사이클 브레이크의 열변형 해석을 위한 지원 프로그램의 개발)

  • 박시형;강석현;이성수
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.1
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    • pp.101-110
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    • 2003
  • Motorcycle industry, for its competitive position, depends on part design technology. This part design has a bulky amount of data and asks the accumulation of advanced technical skill and experience, and fragmentary technical application is not enough to get to the kernel of a problem. Therefore, the improvement of proper productivity - the starting point of engineering design - and useful Design Methodology for products manufacturing are needed. Thus this paper is aimed to create a program that outputs dynamic characteristics of a vehicle when the data from fully understanding on motorcycle's brake system and induced formula for brake design are inputted. This paper is intended to show a creative design method by the thermal analysis data through FEM study and using shape design parameters derived from our programs.

Interfacial phenomena of XLPE/EPDM laminates (XLPE/EPDM laminates의 계면현상)

  • 남진호;서광석;김지환;고광철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.211-214
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    • 1998
  • DC breakdown characteristics and formation of space charge at the interfaces of crosslinked polyethylene (XLPE) /ethylene propylene diene terpolymer (EPDM) laminates were studied. Effects of silicone grease and some chemicals such as crosslinking coagent on the interfacial charge were also studied. Interfacial charge develops at the interface of XLPE/EPDM laminates, which changes depending on heat treatment conditions and types of chemicals coated at the interface. Some chemicals such as maleic anhydride reduce the accumulation of interfacial charge in the XLPE/EPDM laminates. Breakdown strength of EPDM/XLPE laminate through the interface was highest when silicone oil was pasted in the interfaces. Interfacial breakdown strength decreased with the increase of MAH content.

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