• Title/Summary/Keyword: vapor buffering capacity

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Moisture Vapor Management Properties of Fabrics Determining Human Sensorial Comfort in Transient Conditions (동적 상태에서 주관적 착용감에 영향을 미치는 직물의 수증기상태의 수분전달 특성)

  • ;Roger L. Barker
    • Journal of the Korean Society of Clothing and Textiles
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    • v.24 no.7
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    • pp.1073-1080
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    • 2000
  • Moisture transfer property of fabrics has known as one of the most important factors deciding wearer's subjective comfort not only thermally but also of sensorial. As a decisive property of fabric materials in determining human sensorial comfort, moisture vapor management property of heat resistant workwear material was examined in terms of increasing and decreasing rate and maximum value of relative humidity in the microclimate under the sweat pulse situation. An unique moisture regulation index, B$_{d}$, was calculated from the measurements using a novel dynamic sweating hot plate apparatus and was used to assess the buffering capacity of fabrics against a moisture vapor sweat pulse.e.

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Effect of Fiber Content, Yarn Size and Construction of Knit Fabrics on the Buffering Capacity against Water Vapor (편성물의 섬유의 종류, 실의 굵기 및 니트타입에 따른 투습완충능력)

  • Yoo, Hwa-Sook;Hu, Yoon-Sook;Kim, Eun-Ae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.20 no.1
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    • pp.228-238
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    • 1996
  • The purpose of this study was to evaluate the effect of chacteristics of knit fabrics on the microclimate of the skin simulating system. To determine the effect of characteristics of knit fabrics, vapor state of sweat pulse was simulated in the closed system. Different contents of fibers such as cotton, wool and polyester with different yarn size and knit types were chosen for specimens. The changes of humidity and temperature of air layer in the simulated systems were measured. Buffering indices, $K_d$ and $\beta_r$, were determined by considering $\alpha_p, \DeltaP_{max}, t_{max}, and tan\beta$. Physical properties of knit fabrics such as thickness, porosity, air resistance and moisture vapor transport were measured. Results showed that vapor pressure of wool was lower than cotton or polyester This was attributed to the hydrophilicity of wool which absorbed moisture rather quickly and retained in the knit fabric. The time to decrease vapor pressure was faster for polyester than cotton or wool. As a result, $K_d$ was in the order of wool> polye, item> cotton. $\beta_r$ of wool was rower than cotton or polyester due to its lowers porosity and slower desorption rate. For the yarn size, $K_d$ was in the order of 80's> 60's> 30's; thinner and lighter yarn showed better water vapor transport property. For knit type, buffering capacity of single jersey was better than interlock knit fabric. Statistical analysis showed that the air permeability was the most influential factor far the water vapor transport properties.

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The Electrochemical Characteristics of Surface-modified Carbonaceous Materials by tin Oxides and Copper for Lithium Secondary Batteries

  • Lee, Joong-Kee;Ryu, D.H.;Shul, Y.G.;Cho, B.W.;Park, D.
    • Carbon letters
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    • v.1 no.3_4
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    • pp.170-177
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    • 2001
  • Lithium intercalated carbon (LIC) are basically employed as an anode for currently commercialized lithium secondary batteries. However, there are still strong interests in modifying carbon surface of active materials of the anode because the amount of irreversible capacity, charge-discharge capacity and high rate capability are largely determined by the surface conditions of the carbon. In this study, the carbonaceous materials were coated with tin oxide and copper by fluidized-bed chemical vapor deposition (CVD) method and their coating effects on electrochemical characteristics were investigated. The electrode which coated with tin oxides gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. However, the cyclability was improved by coating with copper on the surface of the tin oxides coated carbonaceous materials, which plays an important role as an inactive matrix buffering volume changes. An impedance on passivation film was decreased as tin oxides contents and it resulted in the higher capacity.

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Surface Modification of Synthetic Graphite as an Electrode by Fluidized-bed Chemical Vapor Deposition for Lithium Secondary Batteries (유동상 화힉증착에 의한 리튬이차전지 전극용 탄소재료의 표면개질)

  • Ryu D. H.;Lee Joong Kee;Park D. G.;Yun K. S.;Cho B. W.;Shul Y. G.
    • Journal of the Korean Electrochemical Society
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    • v.3 no.3
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    • pp.173-177
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    • 2000
  • The synthetic carbon was coated with tin oxide and copper by fluidized-bed chemical vapor deposition method. $(CH_3)_4Sn\;and\;Cu(hfac)_{2s}$ were employed as the metallic organic precursor, respectively. The modified synthetic carbons were used for lithium secondary battery anode to investigate their coating effects on electrochemical characteristics as alternative anode materials for lithium secondary batteries. The electrode which prepared by the synthetic carbons(MCMB) coated with tin oxide gave the higher capacity than that of raw material. Their capacity decreased with the progress of cycling possibly due to severe volume changes. But the cyclability was improved by coating with copper on the surface of the tin oxide coated carbon, which plays an important role as an inactive matrix buffering volume changes.