• 제목/요약/키워드: Cold resistance

검색결과 520건 처리시간 0.028초

Heat Shock Proteins: A Review of the Molecular Chaperones for Plant Immunity

  • Park, Chang-Jin;Seo, Young-Su
    • The Plant Pathology Journal
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    • 제31권4호
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    • pp.323-333
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    • 2015
  • As sessile organisms, plants are exposed to persistently changing stresses and have to be able to interpret and respond to them. The stresses, drought, salinity, chemicals, cold and hot temperatures, and various pathogen attacks have interconnected effects on plants, resulting in the disruption of protein homeostasis. Maintenance of proteins in their functional native conformations and preventing aggregation of non-native proteins are important for cell survival under stress. Heat shock proteins (HSPs) functioning as molecular chaperones are the key components responsible for protein folding, assembly, translocation, and degradation under stress conditions and in many normal cellular processes. Plants respond to pathogen invasion using two different innate immune responses mediated by pattern recognition receptors (PRRs) or resistance (R) proteins. HSPs play an indispensable role as molecular chaperones in the quality control of plasma membrane-resident PRRs and intracellular R proteins against potential invaders. Here, we specifically discuss the functional involvement of cytosolic and endoplasmic reticulum (ER) HSPs/chaperones in plant immunity to obtain an integrated understanding of the immune responses in plant cells.

알루미늄 압출공정변수에 따른 재결정층 두께 변화 (The Thickness of Recrystallization Layer during Aluminum Extrusion Process)

  • 오개희;민유식;박상우;장계원
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 춘계학술대회 논문집
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    • pp.266-269
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    • 2005
  • The effect of exit temperature on the thickness of recrystallization layer during Al extrusion process was investigated. The recrystallization layer of an extruded Al alloy is an important feature of the product in a wide range of applications, particularly those within the automotive industry. The thicker recrystallized layer in the Al alloys can give rise to a number of problems including reduced fatigue resistance and orange peel during cold forming. But the interaction of extrusion process variables with the thickness of recrystallization layer is poorly understood, and there is limited information available regarding the role of the main hot extrusion variables. Using the 3650 US ton extrusion press, this paper describes the effect of the main process variables such as billet temperature, ram speed, and exit temperature on the thickness of recrystallization layer for the A6XXX Al alloy.

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Direct strength method for high strength steel welded section columns

  • Choi, Jong Yoon;Kwon, Young Bong
    • Steel and Composite Structures
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    • 제29권4호
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    • pp.509-526
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    • 2018
  • The direct strength method adopted by the AISI Standard and AS/NZS 4600 is an advanced design method meant to substitute the effective width method for the design of cold-formed steel structural members accounting for local instability of thin plate elements. It was proven that the design strength formula for the direct strength method could predict the ultimate strength of medium strength steel welded section compressive and flexural members with local buckling reasonably. This paper focuses on the modification of the direct strength formula for the application to high strength and high performance steel welded section columns which have the nominal yield stress higher than 460 MPa and undergo local buckling, overall buckling or their interaction. The resistance of high strength steel welded H and Box section columns calculated by the proposed direct strength formulae were validated by comparison with various compression test results, FE results, and predictions by existing specifications.

An oil-tolerant and salt-resistant aqueous foam system for heavy oil transportation

  • Sun, Jie;Jing, Jiaqiang;Brauner, Neima;Han, Li;Ullmann, Amos
    • Journal of Industrial and Engineering Chemistry
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    • 제68권
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    • pp.99-108
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    • 2018
  • An oil-tolerant and salt-resistant aqueous foam system was screened out as a possible lubricant to enable cold heavy oil transportation. The microstructures and viscoelasticity and effects of heavy oil, salt and temperature on the foam stability were investigated and new rheological and drainage models were established. The results indicate the foam with multilayered shells belongs to a special microcellular foam. The viscoelasticity could be neglected due to its low relaxation time. The drainage process can be divided into three stages. The foam with quality of 67.9% maintains great stability at high oil and salt concentrations and appropriate elevated temperature.

투습성에 따른 단열재의 단열성능평가 및 고찰 (The estimation on the insulation performance of thermal insulation materials according to water vapor permeance)

  • 김석현;박종일;이민우;홍진관
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2006년도 하계학술발표대회 논문집
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    • pp.1012-1018
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    • 2006
  • In this study, the insulation performance of thermal insulation materials such as glass wool, polyetylene and flexible lastomeric foam according to water vapor permeance was estimated by using experimental correlation equation. The results showed the conductivity increment of flexible lastomeric foam which has very low-permeability (${\le}0.15[ng/{\cdot}s{\cdot}Pa]\;or\;{\mu}{\ge}1,000$) is about 50% lower than that of glass wool with the lapse of ten years. The conclusion is that moisture inevitably accumulated in permeable Insulations reduces insulation performance and also accelerates surface condensation in the case of cold water system.

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고내열 페라이트계 스테인레스 주강의 고온인장특성 평가 (High Temperature Tensile Properties of Heat-resistant Cast Ferritic Stainless Steels)

  • 정현경;이동근
    • 열처리공학회지
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    • 제34권1호
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    • pp.10-16
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    • 2021
  • Exhaust manifold is a very important component that is directly connected to air environment pollution and that requires strict mechanical properties such as high temperature fatigue and oxidation. Among stainless steels, the ferritic stainless steel with body-centered cubic structure shows excellent resistance of stress-corrosion cracking, ferromagnetic at room temperature, very excellent cold workability and may not be enhanced by heat treatment. The microstructural characteristics of four cast ferritic stainless steels which are high heat-resistant materials, were analyzed. By comparing and evaluating the mechanical properties at room temperature and high temperature in a range of 400℃~800℃, a database was established to control and predict the required properties and the mechanical properties of the final product. The precipitates of cast ferritic stainless steels were analyzed and the high-temperature deformation characteristics were evaluated by comparative analysis of hardness and tensile characteristics of four steels at room temperature and from 400℃ to 800℃.

18세기 『산림경제(山林經濟)』에 나타난 고전 농법의 재해석 (Contemporary Interpretation of Traditional Farming Practices Described in 18C Literature 'Sallimgyeongje (山林經濟)')

  • 탁우현;조수미
    • 농촌지도와개발
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    • 제31권2호
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    • pp.67-83
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    • 2024
  • This study aims to explore a biological interpretation of farming practices mentioned in 'Sallimgyeongje(山林經濟)', an agricultural literature published in late 18C, in order to substantiate its scientific practicality and suggest the sustainable direction of modern agriculture. First, the research revealed that weeds and pests were effectively controlled by interspecies interactions such as allelopathy, mutualism, and interplanting. Second, qualified seeds were selected without dependence on chemical treatments by using specific gravity and cold water immersion. Third, the literature proposed plowing methods based on the properties of the soil, which implicated an establishment of healthy landscape mosaic by imitating the succession and introducing the moderate disturbance. Fourth, the genotypes of 37 native rice varieties were speculated based on six phenotype standards, and some of them are expected to have high nutritional value and abiotic stress resistance.

ELECTROTHERMAL PROPERTIES AND RF TRANSMITTANCE OF SPRAY-COATED CNT THIN FILM FOR RADOME DE-ICING APPLICATION

  • JUN HYUK JUNG;JIWON HONG;YOUNGRYEUL KIM;SEOK-MIN YONG;JINWOO PARK;SEUNG JUN LEE
    • Archives of Metallurgy and Materials
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    • 제65권3호
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    • pp.1011-1014
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    • 2020
  • Ice formed on radome surfaces causes communication disruption due to radio-frequency interference (RFI), which reveals the importance of de-icing systems for radomes. As a radome de-icing application, in this work, carbon nanotube (CNT) thin films were fabricated using a spray-coating method, and influence of process parameters on RF transmittance and electrothermal properties was investigated. With the increase of spraying time, sheet resistance of the fabricated film decreases, which results in a decrease of the RF transmittance and improvement of the heating performance. Also, the de-icing capability of the fabricated CNT film was evaluated at -20℃, and efficient removal of ice under cold conditions was demonstrated.

인류학적(人類學的) 분류(分類)에 따른 스트리트 스타일의 발생(發生)과 계보(系譜)에 관한 연구(硏究) (A Study of Origination and Genealogy on Street Style according to Anthropology)

  • 이영재
    • 패션비즈니스
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    • 제11권4호
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    • pp.183-203
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    • 2007
  • This study aims at providing useful fundamental information to re-establish the theories of modern fashion by examining the origination and genealogy of street style. The street styles focusing on caucasoid have a variety of genealogies such as western type, beat, teddy boy, hippie, skinhead, punk, neuron-mantic, indie kid, riot grrrl, grunge and techno cyber punk. In the same period, on the contrary, the streets styles focusing on negroid are zootie, hipster, modernist, rude boy, two-tone, rastafarian, funky, B-boy, fly girl, raggamuffine, bhangra, and acid jazz, which are seen as the culture of the large cities formed along Atlantic Ocean and Caribbean sea like England, America and Jamaica. These have root as the main fashion in western society. Ironically, most of the subculture concentrated on the whites were racists. Because of such a reason, the street styles have been formed as resistance culture that was unable to sympathize with their society and characteristics by distinguishing the whites and the colored people. Zootie or hipster that is one of the street fashion styles was formed in the 1940-50s, while the colored people who lived in the west Indies migrated to England or America. As a minimal modernist style called Ivy look in US, in that time, anti-culture formed by teenagers in whitey, teddy boy and mods fashion can be strictly different from the zootie and hipster. The colored people's street styles of the 1960s developed into aggressive and hard forms from the rude boy and two-tone while their resistance toward the whites was stronger. The rastafarian style researched the peak as the colored people's traditional ethnic characteristics or resistance intention for their freedom in the 1970s. In that time, The colored people's street styles of the 1960s developed into aggressive and hard forms from the rude boy and two-tone while their resistance toward the whites was stronger. The rastafarian style researched the peak as the colored people's traditional ethnic characteristics or resistance intention for their freedom in the 1970s. In that time, the street styles of the whites were mostly the skinhead or hippie. Most of them were racists toward the colored people. The punk type on shown on the whites focused on luxury and exaggerative costume. On the contrary, the funky style of the colored people focused on aggressive nihilism and form. With B-boy, fly girl, reggae, rap music, and break dancing in the 1980s, the subculture gradually told on the high fashion as well as the culture between the whites and the colored people. From such aspects, the colored people tried to maintain their unique traditional characteristics. However, their individual values surged by the coming young generation excluded the colored people's characteristic street styles. Focusing on gender, violence and private success among their major concerns, the raga muffin style that represents multi-races and multi-cultures was formed. The jazz style in the 1990s showed cold post-modernistic eclecticism different from that of the 1940s-50s. Simultaneously, the various classes appeared their street styles by emphasizing on each personality. Now that we are living in multi-cultural society, a human race or nationalism concept is getting obscurer. There is no obvious boundary line in the differences between human race and its fashion.

알루미늄 엣칭부산물을 첨가한 CPE 고무재료의 난연성 및 내열성 연구 (Study on the Flame Retardation and Thermal Resistance for CPE Rubber Material Added Etching By-product of Aluminum)

  • 김경환;이창섭
    • 대한화학회지
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    • 제45권4호
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    • pp.341-350
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    • 2001
  • 자동차 Oil cooler용 호스를 구성하는 클로로폴리에틸렌(CPE) 고무재료의 내열 및 난연성을 향상시키기 위하여 수산화알루미늄을 내열 및 난연제로 제조한 배합고무의 가황틀성, 물리적 성질, 내열성, 난연성을 조사하였으며, 실험결과로부터 고무와 난연제의 최적배합조건을 도출하였다. 고무시편을 제조하는데 사용된 고무재료는 화학적 내식성과 내한성이 우수하면서도 가격이 저렴한 클로로폴리에틸렌 고무를 사용하였으며, 내열 및 난연제로서는 알루미늄 표면 처리과정에서 발생되는 에칭부산물을 분쇄와 정제를 거쳐 가공한 수산화알루미늄을 사용하였고, 분말은 XRD(X-ray diffraction), PSA(Particle Size Analysis), SEM(Scanning Electron Microscopy) 및 ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectroscopy)로 입자의 상, 크기, 분포, 형태 및 성분을 분석한 후 CPE 고무재료와 0∼80 phr범위에서 훈련하였다. CPE배합 고무의 경도, 인장강도, 신장율, 인장응력 및 열적특성을 분석한 결과, 고무재료규격을 초과하지 않는 범위 내에서 최대의 내열 및 난연효과를 주는 수산화알루미늄의 첨가량은 40 phr로 나타났으며, 이 배합비에서 클로로폴리에틸렌의 난연성은 3배 향상되었다.

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