• Title/Summary/Keyword: Critical materials

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A Study on the Design Concept of Critical Regionalism through the Contemporary Architecture (현대 건축을 통해서 본 비판적 지역주의의 개념적 표현)

  • Chung Hyo-Kyung
    • Korean Institute of Interior Design Journal
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    • v.13 no.6
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    • pp.20-28
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    • 2004
  • The purpose of this research is to understand and explore the view of the current architectural and interior design approach through Critical Regionalism created as one of the movements opposed to Contemporary. Critical Regionalism as a critical view about the contemporary architecture is based on integrated critical thinking toward a built environment surrounded by regional facts such as natural environment, materials, light, weather, unique culture where exist the specific places. The architectural themes of Critical Regionalism based on Kenneth Frampton's view and interpretation about contemporary architecture can be understood as follows; the concept of the place, tectonics, expression by abstraction and phenomenologlcal interpretation. Critical Regionalism has two distinctive features, which are the connection to the Contemporary and critical aspects to develop processes of an architectural design.

Synthesis of Epoxidized Soybean Oil (ESO) and its Blends with Tetrafunctional Epoxy Resins (Epoxidized soybean oil(ESO)의 합성 및 4 관능성 에폭시 수지/ESO 블렌드 시스템의 물성)

  • Lee, Jae-Rock;Jin, Fan-Long;Park, Soo-Jin
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.180-183
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    • 2003
  • In this work. a potential inexpensive epoxy resin. epoxidized soybean oil (ESO) was synthesized and applied as a toughening agent for 4.4'-tetradiglycidyl diaminodiphenyl methane (TGDDM). The chemical structure of ESO was characterized by FT-IR, $^1H NMR, and ^{13}C NMR$ spectroscopy. The curing behaviors. thermal stabilities. fracture toughness. and flexural strength of TGDDM/ESO blend systems were investigated by using the dynamic DSC. thermogravimetric analysis (TGA). and flexural tests. The thermal stabilities of TGDDM/ESO blend systems were decreased with increasing ESO contents. whereas the critical stress intensity factor ($K_{IC}$) and flexural strength ($\sigma_f$) were increased with ESO contents up to 10 wt% ESO.

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HACCP in Changran Jeotgal

  • Park Mi-Yeon;Choi Seung-Tae;Chang Dong-Suck
    • Fisheries and Aquatic Sciences
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    • v.5 no.1
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    • pp.48-53
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    • 2002
  • The HACCP (hazard analysis critical control point) concept becomes an important aspect of Good Manufacturing Practices (GMP) in safe food production. The HACCP plan was developed with food safety objective. The authors already carried out hazards analysis on Changran Jeotgal manufacturing process in a previous report. In this study we developed a HACCP plan on the manufacturing process of Changran Jeotgal. We could decide two CCPs those were salt concentration and eliminations of foreign materials before packaging. Foreign materials should be certainly checked out with laser detector just before packaging. Salt should be maintained more than $8\%$ to inhibit pathogenic bacteria in end product. On the Jeotgal process free water is removed after salting and Jeotgal is seasoned with several subsidiary materials such as com syrup. In result end products have $8\%$ salt with water activity 0.82. Most bacteria are inhibited but some can live in this condition. Materials on the working may be contaminate by pathogens, chemicals or physical hazards. It will be decreased by SSOP (standard sanitary operating program). The SSOP needed in Jeotgal plants is nearly same as other general food manufacturing plants but essential to fulfill HACCP program.

Built-in protection circuit module by using VO2 temperature sensors (VO2 온도센서를 이용한 전원차단 PCM 구성)

  • Song, K.H.;Choi, J.B.;Son, M.W.;Yoo, K.S.
    • Journal of Sensor Science and Technology
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    • v.18 no.1
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    • pp.28-32
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    • 2009
  • Most portable mobile devices employ rechargeable lithium-ion batteries. This lithium-ion battery usually suffers from the possibility of explosion due to heat generation from surrounding atmosphere or internal deficiency during charging or at overuse. To solve these problems, most rechargeable batteries have a built-in protection circuit module (PCM). The resistance of a properly processed $VO_2$ critical temperature sensor (CTS) is changed dramatically at a critical temperature of around $68^{\circ}C$, which can replace some bi-metal, NTC, or PTC sensors embedded in PCM. Such $VO_2$ CTS consumes a very small current at the level of natural discharge. Experimental results showed that this CTS could be applied to a PCM as the PCM could protect the battery while keeping its power consumption at minimum.

Nondestructive Evaluation for Mechanical Degradation of Ultrasuper-Critical Heat-Resistance Steel by Reversible Permeability (가역투자율를 이용한 초초임계압 내열강의 기계적 열화에 관한 비파괴평가)

  • Ahn, SeongBin;Kim, JaeJin;Seo, DongMin;Kim, ChungSeok
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.6
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    • pp.46-52
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    • 2018
  • Nondestructive evaluation for mechanical degradation of ultrasuper-critical (USC) heat-resistance steel, which is attractive to the next generation of power plants is studied by magnetic reversible permeability. The interrelationship between reversible permeability and high-temperature mechanical degradation has been investigated by precise measurement of permeability nondestructively. Also, the effects of microstructural variation on reversible permeability are discussed. Isothermal aging was observed to coarsen the tempered carbides ($Cr_{23}C_6$), generated the intermetallic phases ($Fe_2W$), and grow rapidly during aging. The dislocation density also decreases steeply within lath interior. The peak to peak interval (PPI) of reversible permeability profile decreased drastically during the initial 500 h aging period, and was thereafter observed to decrease only slightly. The variation in PPI is closely related to the decrease in the number of pinning sites and the degradation in tensile strength.

Evaluation on Resistance to Pitting Corrosion of Fe-Cr Alloys via Measurement of the Critical Pitting Temperature (CPT) and Potentiodynamic Polarization According to KS D 0238 (wet, dry), ASTM G 61 and ISO 17475 Standards (Fe-Cr합금의 공식저항성 평가를 위하여 다양한 규격(KS D 0238, ASTM G 61, ISO 17475)에 따라 실시한 동전위 분극 시험과 임계공식온도 측정시험)

  • Kang, Su-Yeon;Lee, Jae-Bong;Kim, Yeong-Ho
    • Korean Journal of Metals and Materials
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    • v.47 no.10
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    • pp.635-643
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    • 2009
  • The resistance to pitting corrosion of Fe-Cr alloys was evaluated by performing potentiodynamic polarization and critical pitting temperature (CPT) tests. For the potentiodynamic polarization tests, various standards were applied, i.e., KS D 0238 (wet, dry), ASTM G 61, and ISO 17475, showing different potentiodynamic polarization results including pitting potentials. ASTM G 61 and ISO 17475 standards presented relatively higher pitting potential while KS D 0238 (dry) indicated lower values than the others. Effects of surface roughness, scan rates, and exposure time to air before tests were also investigated. CPT tests were performed under two different applied potentials, 300 m$V_{SCE}$ and 200 m$V_{SCE}$ in deaerated 1 M NaCl aqueous solution. CPT values and the polarization test results showed a linear relationship.

Drug Release Behavior of Poly($\varepsilon$-caprolactone )-b-Poly( acrylic acid) Shell Crosslinked Micelles below the Critical Micelle Concentration

  • Hong Sung Woo;Kim Keon Hyeong;Huh June;Ahn Cheol-Hee;Jo Won Ho
    • Macromolecular Research
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    • v.13 no.5
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    • pp.397-402
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    • 2005
  • To explore the potential of shell crosslinked micelle (SCM) as a drug carrier, the drug release behavior of poly($\varepsilon$-caprolactone)-b-poly(acrylic acid) (PCL-b-PAA) SCMs was investigated. PCL-b-PAA was synthesized by ring opening polymerization of $\varepsilon$-caprolactone and atom transfer radical polymerization of tert-butyl acrylate, followed by selective hydrolysis of tert-butyl ester groups to acrylic acid groups. The resulting amphiphilic polymer was used to prepare SCMs by crosslinking of PAA corona via amidation chemistry. The drug release behavior of the SCMs was studied, using pyrene as a model drug, and was compared with that of non-crosslinked micelles, especially below the critical micelle concentration (CMC). When the shell layers were crosslinked, the drug release behavior of the SCMs was successfully modulated at a controlled rate compared with that of the non-crosslinked micelles, which showed a burst release of drug within a short time.