• Title/Summary/Keyword: temperature cycles

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The Deformation of Knitted Cotton Fabrics with/without Spandex During Laundering (스판덱스 혼합 면 편성물과 면 편성물의 세탁에 따른 변형 비교)

  • Chung, Haewon;Kim, Ku-Ja;Kim, Mikyung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.2 s.150
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    • pp.296-305
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    • 2006
  • This study evaluate the effect of laundering on the deformation of knitted spandex/cotton fabrics compared with that of knitted cotton fabrics. Commercial knitted spandex/cotton and knitted cotton fabrics for T-shits were laundered in a drum-type washing machine and dried in a tumble dryer. Wale spirality, shrinkage, elastic recovery and surface contour of knitted fabrics were investigated under different laundering conditions: washing temperature, presoaking time and washing cycles. Knitted spandex/cotton fabrics had a lower angle of spirality than knitted cotton fabrics. After the first washing cycle, the angles of spirality of all the fabrics had decreased greatly. Knitted cotton fabric of low density deformed more than that of higher density. Knitted spandex/cotton. fabric of low density shrank less, because of the greater extension given during heat-set. Permanent elongation length at the 80$\%$ extension was longer than at the 50$\%$ extension, and the knitted spandex/cotton fabric which was expanded greatly during heat-set had a lower elastic recovery rate. The surface appearance of the knitted spandex/cotton fabrics was worsl~ than that of the knitted cotton fabrics before laundering and after repeated laundering, because of the much protruded cotton fibers from the yarns.

A Study on Change of Texture During Thermal Cycling in Cu-Zn-AI Shape Memory Alloy (Cu-Zn-AI 형상기억 합금의 열사이클에 따른 집합조직의 변화에 관한 연구)

  • Hong, D.W.;Park, Y.K.
    • Journal of the Korean Society for Heat Treatment
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    • v.5 no.3
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    • pp.179-185
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    • 1992
  • The shape memory effect results from the martensite transfomation of each individual grain. Thus it is necessary to study the texture and its variation. In this study the change of texture during thermal cycling and it's effect on shape memory ability are investigated. The major component of the rolling texture in the parent phase is identified (001) [110], and minor components are (112) [110], (111) [112], {hkl}<100> fiber texture is developed at $45^{\circ}$ from rolling direction. In the case of martensite phase, it is estimated that the major component is (011) [100] and the minor components are (105) [501], (010) [101] and (100) [001]. According to thermal cycling. severity of texture, especially (001) [110] component in parent phase and (011) [100] component in martensite phase are increased. The shape memory ability is increased with increase of thermal cycles and also increased as the direction of specimen approach to $45^{\circ}$ from rolling direction. After first thermal cycling the temperature of transformation can be define clearly and Ms and As are raised by thermal cycling.

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Pink Root of Onion Caused by Pyrenochaeta terrestris (syn. Phoma terrestris)

  • Kim, Yong-Ki;Lee, Sang-Bum;Shim, Hong-Sik;Lee, Chan-Jung;Kim, Hee-Dae
    • The Plant Pathology Journal
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    • v.19 no.4
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    • pp.195-199
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    • 2003
  • Pink root of onion occurred in the fields of the Onion Experimental Station and in the main onion cultivation area in Korea in 1998 and 1999, respectively. The casual fungus of pink root was isolated only from apricot agar. Formation of pycnidia and pycnidiospores of the fungus was highest in alternating cycles of 12 hours near ultraviolet light and 12 hours in dark condition. Its morphological characteristics and pigment formation on water agar were identical with that of Pyrenochaeta terrestris. The optimum temperature for the growth of the fungus and disease development was $25-28^{\circ}C$. When onion seeds were inoculated with the spore suspension, incubated in test-tube and sown in potted soil, disease symptoms developed in onion roots 7 and 30 days after inoculation.

Surimi Quality from Mechanically Deboned Chicken Meat as Affected by Washing Cycle, Salt Concentration, Heating Temperature and Rate

  • Min, Byung-Jin;Lee, Sung-Ki
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.1
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    • pp.131-136
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    • 2004
  • The effects of salt concentration and heating conditions on the thermal gelation properties of surimi produced from mechanically deboned chicken meat (MDCM) were investigated. Chicken surimi was manufactured by washing (MDCM: 0.5% NaCl=1:4), standing, straining and centrifuging. The fat, water-soluble protein and heme pigment in the MDCM were removed by increasing washing cycles. The compressive force of the chicken surimi increased as the concentration of salt was increased from 0% to 5%. Total gel strength of the surimi measured by texture profile analysis showed a maximum in the range 3-5% NaCl. Microstructural analysis showed that the unfolding network structure of the surimi gel began to appear at NaCl concentrations>2%. The optimum heating condition for gelation was $90^{\circ}C$ for 40 min as this resulted in maximum values for measures of gel strength including compressive force, hardness, fracturability, adhesiveness, springiness, gumminess, chewiness and resilience. Chicken surimi gel formed by cooking at a heating rate of $1^{\circ}C/min$ to $90^{\circ}C$ showed better a texture than gels produced at $1.85^{\circ}C/min$. Our result show that a lower rate of heating improves chicken surimi gelation.

Change in Microstructure and Mechanical Properties of Deoxidized Low-Phosphorous Copper Processed by Accumulative Roll-Bonding with Annealing (ARB가공된 인탈산동의 어닐링에 따른 미세조직 및 기계적 특성 변화)

  • Lee, Seong-Hee;Kim, Chun-Su;Kim, Sang-Shik;Han, Seung-Zeon;Lim, Cha-Yong
    • Korean Journal of Materials Research
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    • v.17 no.7
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    • pp.361-365
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    • 2007
  • A deoxidized low-phosphorous copper processed by eight cycles of accumulative roll-bonding (ARB) was annealed at various temperatures ranging from 100 to $400^{\circ}C$. The annealed copper was characterized by transmission electron microscopy (TEM) and tensile & hardness test. TEM observation revealed that the ultrafine grains developed by the ARB still remained up to $350^{\circ}C$, however above $400^{\circ}C$ they were replaced by equiaxed and coarse grains due to an occurrence of the static recrystallization. The hardness of the copper decreased slightly with the annealing temperature up to $350^{\circ}C$, however they dropped largely above $400^{\circ}C$. Annealing characteristics of the copper were compared with those of an oxygen free copper processed by ARB and subsequently annealed.

Deposition of Functional Organic and Inorganic Layer on the Cathode for the Improved Electrochemical Performance of Li-S Battery

  • Sohn, Hiesang
    • Korean Chemical Engineering Research
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    • v.55 no.4
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    • pp.483-489
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    • 2017
  • The loss of the sulfur cathode material through dissolution of the polysulfide into electrolyte causes a significant capacity reduction of the lithium-sulfur cell during the charge-discharge reaction, thereby debilitating the electrochemical performance of the cell. We addressed this problem by using a chemical and physical approach called reduction of polysulfide dissolution through direct coating functional inorganic (graphene oxide) or organic layer (polyethylene oxide) on electrode, since the deposition of external functional layer can chemically interact with polysulfide and physically prevent the leakage of lithium polysulfide out of the electrode. Through this approach, we obtained a composite electrode for a lithium-sulfur battery (sulfur: 60%) coated with uniform and thin external functional layers where the thin external layer was coated on the electrode by solution coating and drying by a subsequent heat treatment at low temperature (${\sim}80^{\circ}C$). The external functional layer, such as inorganic or organic layer, not only alleviates the dissolution of the polysulfide electrolyte during the charging/discharging through physical layer formation, but also makes a chemical interaction between the polysulfide and the functional layer. As-formed lithium-sulfur battery exhibits stable cycling electrochemical performance during charging and discharging at a reversible capacity of 700~1187 mAh/g at 0.1 C (1 C = 1675 mA/g) for 30 cycles or more.

Cure Cycle for Thick Glass/Polyester Composites (두꺼운 유리섬유/폴리에스터 복합재료를 위한 경화 사이클)

  • 김형근;오제훈;이대길
    • Composites Research
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    • v.14 no.2
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    • pp.33-42
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    • 2001
  • The cure kinetic equation fur 52-glass/polyester prepreg composites was established through DSC (differential scanning calorimetry). Using the established kinetic equation, the temperature distribution of the thick composite was calculated considering the change of heat transfer resistance due to resin impregnation of bleeder plies used. In order to reduce the overheat during cure of thick glass fiber composites, the cure cycle was modified by introducing the cooling and reheating steps. Then the thick glass composites were cured both by the conventional cycle without any cooling or reheating step and the modified cure cycle. The mechanical properties of the thick composites cured by the both cycles were tested by the short beam shear test and the Barcol hardness test, and then their results were compared.

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End Use Tactile Property of the Split-type Nylon/PET Microfiber Fabrics (마찰과 세탁에 의한 극세섬유 직물의 표면과 촉감변화에 관한 연구)

  • 오경화;윤재희
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.3_4
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    • pp.539-545
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    • 2004
  • In this study, the effect of washing, bleaching, and abrasion on tactile and the water absorption properties of the split-type Nylon/Polyester (N/P) microfiber pile-knit was investigated under various enduse conditions. We examined the water absorption and surface properties of PET microfiber which will be very useful in the future. We also studied the variations of their performance during usage caused by friction and repeated washing, regard to all kinds of physical, chemical changes which will appear while using those textiles. Progress in further splitting of PET microfiber fabric is observed with increases in the number of washing and bleaching cycles, and treatment temperature. Initial water absorption (%) was increased with progress in splitting, which provided efficient capillary channel. Surface properties were varied with additional splitting by washing and abrasion. Formation of pilling and splitting by abrasion increase surface roughness, diminishing tactile property, and reduced water absorption property. The current results from this study is expected to provide the appropriate washing management guide to consumers, and to inform end-use performance of product to a producer for improving product quality.

A Characteristic Study of Low Cycle Fatigue for Rolled STS 304 Steel (STS 304 압연강의 저주기 피로특성에 관한 연구)

  • Kim, C.H.;Park, Y.M.;Bae, M.K.;Kim, H.S.;Kim, T.G.
    • Journal of the Korean Society for Heat Treatment
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    • v.31 no.1
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    • pp.18-23
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    • 2018
  • In this study, low cyclic fatigue test was carried out at room temperature condition for rolled STS304 steel. The results of this study show that rolled STS304 steel has excellent static tensile strength and fatigue characteristics. The relationship between plastic strain range and fatigue life was examined using the triangular wave in order to predict the low cycle fatigue life of rolled STS304 steel by Coffin-Manson equation. Cyclic behavior of rolled STS304 steel was characterized by cyclic hardening with increasing number of cycle through the Hysteresis loop analysis and cyclic response of maximum stress versus number of cycles. It is found that the plastic deformation energy consumed per cycle is reduced by calculating the area of the hysteresis loop.

Sub-class Clustering of Land Cover over Asia considering 9-year NDVI and Climate Data

  • Lee, Ga-Lam;Han, Kyung-Soo;Kim, Do-Yong
    • Korean Journal of Remote Sensing
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    • v.27 no.3
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    • pp.289-301
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    • 2011
  • In this paper an attempt has been made to classify Asia land cover considering climatic and vegetative characteristics. The sub-class clustering based on the 13 MODIS land cover classes (except water) over Asia was performed with the climate map and the NOVI derived from SPOT 5 VGT D10 data. The unsupervised classification for the sub-class clustering was performed in each land cover class, and total 74 clusters were determined over the study area. Via these clusters, the annual variations (from 1999 to 2007) of precipitation rate and temperature were analyzed as an example by a simple linear regression model. The various annual variations (negative or positive pattern) were represented for each cluster because of the various climate zones and NOVI annual cycles. Therefore, the detailed land cover map as the classification result by the sub-class clustering in this study can be useful information in modelling works for requiring the detailed climatic and vegetative information as a boundary condition.