• Title/Summary/Keyword: internal resistance

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Performance Evaluation of Fire Resistance of High Strength Concrete by Incorporation of Combined Fiber (복합섬유 혼입에 따른 고강도콘크리트의 내화 성능 평가)

  • Shin, Jae-Kyung;Park, Jong-Ho;Jeong, Yong;Moon, Hyung-Jae;Kim, Jeong-Jin;Park, Soon-Jeon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.423-424
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    • 2010
  • This study purpose is to develop the high fireproof concrete which applied method of combined fiber mixed with polymer powder and organic fiber which can satisfy flowability and the fire resistance properties for construction of the super tall building. According to the results, in case of polymix it is effective to the reduction of internal temperature rise and spalling resistance so it as fire resistance that is similar to existing fiber cocktail.

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Characteristic of HVOF AISI316-WC Coating Layer on Stainless Steel Separator for PEMFC (고분자 전해질 연료전지용 스테인리스강 분리판의 HVOF AISI316-WC 코팅층 특성)

  • Nam, Dae-Geun;Kang, Nam-Hyun;Park, Yeong-Do;Kim, Young-Seok
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.1-5
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    • 2008
  • Stainless steels have been widely considered as metallic separators, due to their passive surface film, which is good for corrosion resistance. However, the high resistivity of the passive film increases interfacial contact resistance between the separators and electrodes. Stainless steels thermal spray coated with a mixture of tungsten carbide and stainless steel powders showed that the coated layer safely combined with the matrix but they suffered many internal defects including voids and cracks. Many cracks were formed in the coated layer and the interface of the matrix and the coated layer during the rolling process. The coated and rolled stainless steels showed lower interfacial contact resistance and corrosion resistance than bare stainless steel because of low resistivity of tungsten carbide and numerous defects, which caused crevice corrosion, in the coated layer.

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Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

  • Jin, Chung Keun;Lim, Sung Hyung
    • Corrosion Science and Technology
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    • v.14 no.5
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    • pp.207-212
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    • 2015
  • The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

The Impact of Organokines on Insulin Resistance, Inflammation, and Atherosclerosis

  • Choi, Kyung Mook
    • Endocrinology and Metabolism
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    • v.31 no.1
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    • pp.1-6
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    • 2016
  • Immoderate energy intake, a sedentary lifestyle, and aging have contributed to the increased prevalence of obesity, sarcopenia, metabolic syndrome, type 2 diabetes, and cardiovascular disease. There is an urgent need for the development of novel pharmacological interventions that can target excessive fat accumulation and decreased muscle mass and/or strength. Adipokines, bioactive molecules derived from adipose tissue, are involved in the regulation of appetite and satiety, inflammation, energy expenditure, insulin resistance and secretion, glucose and lipid metabolism, and atherosclerosis. Recently, there is emerging evidence that skeletal muscle and the liver also function as endocrine organs that secrete myokines and hepatokines, respectively. Novel discoveries and research into these organokines (adipokines, myokines, and hepatokines) may lead to the development of promising biomarkers and therapeutics for cardiometabolic disease. In this review, I summarize recent data on these organokines and focus on the role of adipokines, myokines, and hepatokines in the regulation of insulin resistance, inflammation, and atherosclerosis.

Characterizations of Cr-P-PTFE composite coatings electroplated from trivalent chromium-based bath

  • Park, Jong-Kyu;Byoun, Young-Min;Seo, Sun-Kyo;Park, Su-Young;Choi, Sun-Woo
    • Journal of Ceramic Processing Research
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    • v.19 no.6
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    • pp.455-460
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    • 2018
  • Chromium plating is a common surface treatment technique extensively applied in industry due its excellent properties which include substantial hardness, abrasion resistance, corrosion resistance, surface color, and luster. In this study, the effect of PTFE on corrosion behavior of Cr-P plating, low carbon steel substrates are electroplated in Cr(III) baths without and with PTFE. Trivalent chromium carbon plating was electroplated from trivalent chromium sulfate-based baths with different PTFE dispersion contents. The study focused on the microstructure, PTFE content, roughness, and corrosion resistance of the Cr-P-PTFE composite plating. Scanning electron microscopy and atomic force microscopy images showed a smoother plating and a decrease in the surface roughness of the electrodeposited. The results demonstrate that PTFE eliminates the cracks within plating by reducing internal stress. Therefore, the corrosion resistance of Cr-P-PTFE composite platings were better than that of Cr-P alloy platings.

Effect of Isothermal annealing on the Corrosion Resistance of an Amorphous Alloy (비정질 합금의 부식저항성에 미치는 열처리의 영향)

  • Shin, Sang-Soo;Lee, Chang-Myeon;Yang, Jae-Woong;Lee, Jae-Chul
    • Korean Journal of Metals and Materials
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    • v.46 no.2
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    • pp.53-57
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    • 2008
  • This study examined the role of excess free volume on the corrosion resistance of an amorphous alloy. Corrosion behaviors were monitored on the amorphous alloys, of which amount of free volume was controlled via the isothermal annealing below the glass transition temperature, using immersion tests and potentiodynamic polarization tests in HCl aqueous solutions. It was found that the corrosion resistance of the amorphous alloy is improved by reducing the amount of excess free volume. The possible reason explaining the experimental result was discussed from the viewpoint of the internal energy associated with the annihilation of excess free volume.

A Study on Polarization of MCFC (MCFC의 분극특성에 관한 연구)

  • Eom, S.W.;Kim, G.Y.;Yun, M.S.
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.1242-1244
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    • 1993
  • As increasing of internal resistance value at MCFC electrode, out voltage of battery is decreased currently. We measured overpotential and IR drop which consist of resistance factors in MCFC electrode, and calculated out voltage from open circuit voltage.

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The Relationship between MDR1 Polymorphisms and the Response to Etoposide/Cisplatin Combination Chemotherapy in Small Cell Lung Cancer (소세포폐암에서 Multidrug Resistance-1 유전자의 다형성과 Etoposide-cisplatin 항암화학요법 반응의 관계)

  • Sohn, Ji Woong;Lee, Shin Yup;Lee, Su Jung;Jeon, Hyo-Sung;Lee, Jae Hee;Park, Jae Hyung;Kim, Eun Jin;Kang, Young Mo;Lee, Jae-Tae;Cha, Seung Ick;Kim, Chang Ho;Jung, Tae Hoon;Park, Jae Yong
    • Tuberculosis and Respiratory Diseases
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    • v.58 no.2
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    • pp.135-141
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    • 2005
  • 배경 및 목적 : Multidrug Resistance-1 (MDR1) 유전자는 다약제내성에 관여하는 P-glycoprotein을 암호화한다. MDR1 유전자의 다형성은 P-glycoprotein의 발현과 기능의 차이를 일으켜 항암화학요법 반응에 영향을 미칠 수 있을 것이다. 저자들은 소세포폐암 환자에서 MDR1 유전자의 다형성과 일배체형에 따른 항암화학요법에 대한 반응을 조사하였다. 대상 및 방법 : 경북대학병원에서 병리적으로 소세포폐암으로 진단받고 etoposide-cisplatin 항암화학요법을 받은 54명을 대상으로 하였다. 전혈 5cc에서 DNA를 추출하고 PCR-RFLP법을 통해 MDR1 유전자 엑손 21의 2677G>T 다형성과, 엑손 26의 3435C>T 다형성을 조사하고 다형성과 일배체형에 따른 항암화학요법의 반응을 조사하였다. 결 과 : 2677G>T 유전자형에 따른 항암화학요법의 반응은 유의한 차이가 없었다. 3435 CC 유전자형은 3435 CT+TT 형에 비해 치료 반응율이 유의하게 높았다 (P = 0.025). 유전자형 분석 결과와 일치되게 2677G/3435C 일배체형은 다른 일배체형에 비해 치료반응을 보이는 경우가 유의하게 많았다 (P = 0.015). 결 론 : 소세포폐암에서 MDR1 유전자의 2677G>T와 3435C>T 다형성 및 이들 다형성의 일배체형은 etoposide-cisplatin 항암화학요법의 반응을 예측할 수 있는 지표로 사용될 수 있을 것으로 생각된다.

Development of Real-time Monitoring Device ($\textrm{JELLI}^{TM}$ chip) for Phase Inversion of Emulsions Under Shear Flow (전단응력 하에서 에멀젼 상 변이의 실시간 측정을 위한 전기 유변학적 연구)

  • 백승재;이영진;남윤정;김진한;김한곤;강학희
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.1
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    • pp.59-62
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    • 2004
  • To know what happens to the internal structure of emulsions under high shear flow is very important for cosmetic product development because it is highly relevant to the physical degradation of emulsions during the application upon the skin. Here, in order to investigate the response of emulsions against the external shear forces, we designed a new device, .JELLI$^{TM}$ (Joint Electro-rheometer for Liquid-Liquid Inversion) chip, for the measurement of electrical and rheological properties of emulsions under shear flow. By using this device, we examined the real-time changes in conductivities of oil-in-water (O/W) and water-in-oil (W/O) emulsions on the artificial skin during large deformation under shear flow. In this study, O/W and W/O emulsions having various volumes were prepared. After emulsions were homogeneously applied on the artificial skin, the electrical resistance and viscosity changes were monitored under steady shear flow. In case of O/W emulsions, the resistance increased as a function of time. The resistance showed more dramatic increase as the increase of the internal oil phase. It was also found that the viscosity change was proportional to the resistance variation. This phenomenon might be caused by decreased resisting forces against the shear flow because of the breakdown of the internal phase.the internal phase.

Drug Resistance of Mycobacterium Tuberculosis in Korea (한국인 결핵환자로 부터 톨리된 인형결핵균의 약제내성)

  • Kim, Sang-Jae;Hong, Young-Pyo;Han, Yong-Chul;Kim, Sung-Jin
    • Tuberculosis and Respiratory Diseases
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    • v.38 no.2
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    • pp.99-107
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    • 1991
  • Drug resistance of M. tuberculosis has been investigated with isolates from patients screened out of the sample population of the nationwide tuberculosis prevalence surveys or from the routine cultures. The results showed a close inverse relationship between prevalence of drug resistance and efficiency of the past or current treatment regimens of NTP. Individual drug resistance also showed a close relationship with the extent of use of the relevant drugs. Drug resistance was found in 38.0% of M. tuberculosis isolates from patients found in 1965 survey and remained unchanged until it increased upto 48.0% in 1980 survey. The resistance prevalence, however, dropped to 30.8% in 1985 and further to 25.3% in 1990 survey. Such decrease was fairly well coincided with a continuous increase of the treatment efficiency (from 60% in 1984 to 77% in 1989) in 1980s. Initial drug resistance also showed a similar trend, namely 26.2% in 1965, 23.9% in 1970, 20.1% in 1975, 30.6% in 1980, 17.4% in 1985, and 15.0% in 1990. The similar figures were observed in M. tuberculosis isolates from patients diagnosed in the routine services. Higher prevalence of initial drug resistance was observed among urban patients than rural patients and among young patients than old patients. These findings signify that a continuous survey on drug resistance permits to monitor efficiency of treatment programme of the country.

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