• Title/Summary/Keyword: Mixed sensitivity

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Fabrication and Characterization of Porous Non-Woven Carbon Based Highly Sensitive Gas Sensors Derived by Magnesium Oxide

  • Kim, Yesol;Cho, Seho;Lee, Sungho;Lee, Young-Seak
    • Carbon letters
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    • v.13 no.4
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    • pp.254-259
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    • 2012
  • Nanoporous non-woven carbon fibers for a gas sensor were prepared from a pitch/polyacrylonitrile (PAN) mixed solution through an electrospinning process and their gas-sensing properties were investigated. In order to create nanoscale pores, magnesium oxide (MgO) powders were added as a pore-forming agent during the mixing of these carbon precursors. The prepared nanoporous carbon fibers derived from the MgO pore-forming agent were characterized by scanning electron microscopy (SEM), $N_2$-adsorption isotherms, and a gas-sensing analysis. The SEM images showed that the MgO powders affected the viscosity of the pitch/PAN solution, which led to the production of beaded fibers. The specific surface area of carbon fibers increased from 2.0 to $763.2m^2/g$ when using this method. The template method therefore improved the porous structure, which allows for more efficient gas adsorption. The sensing ability and the response time for the NO gas adsorption were improved by the increased surface area and micropore fraction. In conclusion, the carbon fibers with high micropore fractions created through the use of MgO as a pore-forming agent exhibited improved NO gas sensitivity.

A study on the formation of Youth's Fashion based on Street Fashion (스트리트 패션을 근원으로 한 영 패션의 형성에 대한 연구)

  • 신혜영
    • Journal of the Korean Society of Costume
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    • v.27
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    • pp.5-16
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    • 1996
  • In today's fashion Street is a birthplace of new generation fashion and Street Fashion have frequently influenced on high fashion. From this view point this study is a meaningful approach to forecast future fashion trend by examining the street style of youth who are regarded as Street Fashion leaders. The purpose of this study is to examine the Youth Fashion style in early 1990s and to pro-vide a reference to fashion designer and mer-chandiser in trend forecasting and product plan-ning. This study is focused on 1990s Youth Fashion style through the historical Street Fashion : 1950s Teddy boys & Mods 1960s Hippies & Skinhead and 1970s Punk. There were mainly two popular Street Fashion phenomena in early 1990s. There were mainly two popular Street Fashion phenomena in early 1990s. One is grunge fashion created by new gener-ation in opposition to existing generation society and impacting on hish fashion leaders. The other is Remix style that is mixed : sub culture fashion originated by young group in 1950-1970s with 1990s sensitivity. Both fashion styles origionated and led by youth of street have influenced on famous high fashion designeres as well as the general public. Street Fashion will continue to play an import-ant role in future fashion and more study and interest on Street Fashion should be taken by fashion forecaster and related.

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SME Profitability of Trade Credit during and after a Financial Crisis: Evidence from Korea

  • KWON, Ohsung;HAN, Seung Hun;LEE, Duk Hee
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.7
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    • pp.35-47
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    • 2020
  • An economic downturn can occurred through unexpected events in various fields, such as the subprime mortgage crisis and the outbreak of Coronavirus Disease-2019 (COVID-19). Trade credit is important for small- and medium-sized enterprises (SMEs), especially during a monetary contraction, as it is the last option for firms that lack bank credit. This study aims to determine whether trade credit is profitable for the buyer and supplier firms during and after a financial crisis. We use panel data consisting of all trade credit transactions and financial statements of 5,751 Korean firms during the period 2008-2012. It shows that trade credit is more profitable for both buyers and suppliers in the post-crisis period than during the crisis. Moreover, trade payable is more effective for unconstrained buyers than for constrained buyers. Finally, a mixed strategy is superior to an aggressive or passive strategy of SMEs. The results suggest less profitability of trade credit during a period of contraction and greater sensitivity of the buyer SMEs, emphasizing the idiosyncratic liquidity strategy of each firm. This study can be helpful to develop a strategy of profitable trade credit for SMEs and to establish a policy of managing liquidity for the authority.

A Quick Novel Method to Detect the Adulteration of Cow Milk in Goat Milk

  • Lee, Chi-Chei;Chang, His-Shan;Sheen, Hua-Shan
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.3
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    • pp.420-422
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    • 2004
  • This study was to demonstrate a rapid novel method for detection of adulterated cow milk in goat milk using modified staining protocol after native polyacrylamide gel electrophoresis (PAGE). Samples of cow milk and goat milk containing 0, 0.5, 1.0 and 2.0% (v/v) of cow milk were analyzed. Low levels of cow milk mixed in goat milk were identified by the presence of higher mobility of $\beta$-lactoglobulin A ($\beta$-Lg A) in cow milk. By mini-gel electrophoresis, a distinguishable protein profile was visualized in 25 min using the modified Coomassie blue staining solution, in which methanol (50%) was replaced with ethanol (20%) and the concentrations of Coomassie blue and acetic acid were reduced from 2 to 0.13% and 10 to 5%, respectively. To visualize the milk proteins, gels in the staining solution were water-bathed in boiling water for 5 min and then cooled down immediately for 3-5 min. The sensitivity of this method is relatively high, allowing examination of 1% cow milk in goat milk. The procedure presented here is also very cost-effective due to less reagents needed. This simplified method would be useful and applicable to dairy industry for routine examination of goat milk.

Species-Specific Duplex PCR for Detecting the Important Fish Pathogens Vibrio anguillarum and Edwardsiella tarda

  • Jo, Geon-A;Kwon, Sae-Bom;Kim, Na-Kyeong;Hossain, Muhammad Tofazzal;Kim, Yu-Ri;Kim, Eun-Young;Kong, In-Soo
    • Fisheries and Aquatic Sciences
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    • v.16 no.4
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    • pp.273-277
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    • 2013
  • Vibriosis caused by Vibrio anguillarum and edwardsiellosis caused by Edwardsiella tarda are septicemic diseases of many commercially important freshwater and marine fishes, and threaten the aquaculture industry in Korea. Early diagnosis and accurate identification of these two bacterial species could help to prevent these diseases and minimize the damage to cultured marine species. This study designed a duplex polymerase chain reaction (PCR) method for the simultaneous detection of two major fish pathogens: V. anguillarum and E. tarda. Each pair of oligonucleotide primers exclusively amplified the target groEL gene of the specific microorganism. Twenty-two Vibrio and ten non-Vibrio enteric species were used to check the specificity of the primers, which were found to be highly specific for the target species, even among closely related species. The detection limit was 400 pg for V. anguillarum and 4 ng for E. tarda when mixed purified DNA was used as the template. This assay showed high specificity and sensitivity in the simultaneous detection of V. anguillarum and E. tarda from artificially inoculated seawater and fish.

Effect of Lactic Acid Bacteria on the Growth of Yeast from Mul-kimchi (젖산균이 물김치에서 분리한 효모의 생육에 미치는 영향)

  • 송현주;박연희
    • Microbiology and Biotechnology Letters
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    • v.20 no.2
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    • pp.219-224
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    • 1992
  • The changes of yeast population were investigated in Mul-kimchi containing 3% salt, fermented at $15^{\circ}C$. The total viable count increased to the maximum at the optimum ripening period and then decreased rapidly. Among twenty-nine strains isolated at the optimum ripening period, the yeasts of genus Saccharomyces were predominant. The growth of five strains, Saccharomyces saitoanus Y17, Saccharomyces capensis Y29, Saccharomyces chevalieri Y13, Kluyveromyces fragilis Y2, Torulopsis candida Y9, was measured in mixed culture with each selected lactic strains, hctobaczllus plantarum Lp2, Pedzococcus pentosaceus PI, Leuconostoc mesenteroides Lu5. The results indicated that all the yeasts tested were inhibited significantly by lactic strains, however the sensitivity of yeast strains varied greatly.

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A Study on the Fabric Trend and Characteristics of 1990's Women's wear (1990년대(年代) 국내(國內) 여성복(女性服) 소재경향(素材傾向)과 특성(特性)에 대(對)한 연구(硏究))

  • Ha, Jung-Won;Cho, Kyu-Hwa
    • Journal of Fashion Business
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    • v.3 no.3
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    • pp.69-78
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    • 1999
  • The purpose of this thesis is to investigate of fabric characteristics in women's wear as reviewing the fabric trends in 1990's domestic fashion. As a method to accomplish this research, I have examined the articles related to fashion fabric and fashion trend magerzines. This study considered women's wear relatively used diverse fabrics, there was not previous study regarding the fabrics used in domestic, since the 1990's. The social fators for the 1990's fashion were the influence of the informed, the increased concern for the ecological environment, the sattlement of young popular culture, the increase of resonable consume and social anxiety. To understand the fashion trends of the 1990's women's wear, it is divided three periods. The traditional period is from 1991 to 1993, the mixed period of the naturalism and the technology is from 1994 to 1995, the retro period is from 1996 to 1999. The charateristics of the fabrics used in 1990's women's wear were the appearance of various functional fabrics, the development of new synthetic fabric with high sensitivity, the popularization of circular knit, the fabrics with a retro mood toward traditional feminine mood and the blending of fabrics. The fashion of 1990 have had the characteristics of various utilization of the materials on the base of reasonable and practical trends than the changes of design and detail.

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Matrix Modification for Graphite Furnace Atomic Absorption Spectrophotometric Determination of Volatile Elements(III) Trace Bismuth

  • Kim, Young-Sang;Choi, Jong-Moon;Kim, Young-Man
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.435-442
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    • 1995
  • A matrix modification was studied for the determination of trace bismuth in water samples by graphite furnace atomic absorption spectrophotometry. The type and quantity of modifiers as well as the use of auxiliary modifiers were investigated to realize the efficient modification. Palladium was chosen as a single modifier. By the addition of palladium($5{\mu}g/mL$) to 100 ng/mL bismuth solution, the temperatures could be raised from $500^{\circ}C$ to $1,300^{\circ}C$ for the charring and from $2,000^{\circ}C$ to $2,200^{\circ}C$ for the atomization as well as the sensitivity and reproducibility were improved. The absorbance of bismuth was maximum and not changed in the range of Pd $3-25{\mu}g/mL$. And several materials were examined as an auxiliary modifier. The mixed solution of $1{\mu}g/mL$ palladium and $200{\mu}g/mL$ nickel have raised the temperatures as with $5{\mu}g/mL$ palladium only. The maximum absorbance of bismuth was shown in the nickel concentration range of $100-300{\mu}g/mL$ in $1{\mu}g/mL$ palladium modified system. With such optimum conditions, the trace amount of bismuth in several water samples could be determined by a calibration curve method, and good recoveries were also obtained.

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Analysis of the Dye Absorption Behavior in Accordance with the Dye Structure in the Cold Pad Batch Dyeing of Cotton Knit (면니트의 CPB 염색에서 염료 구조에 따른 흡진 거동 분석)

  • Hong, Seok Il;Nam, Chang Woo;Lee, Woosung
    • Textile Coloration and Finishing
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    • v.28 no.3
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    • pp.175-182
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    • 2016
  • To investigate dyeing behaviors in accordance with dye structure in cold pad batch dyeing of cotton knit, monochlorotriazine-vinylsulfone bifunctional dyes and monofluorotriazine-vinylsulfone bifunctional dyes were prepared. The spectral property and solubility of the dyes were tested and compared with the imported dyes. In addition, exhaustion behaviors of individual and mixed dye solutions were measured to examine the influence of dye structure on dyeing behavior in cold pad batch dyeing. The substantivity, fixation, migration index and half dyeing time were also calculated for further analysis of dyeing behavior of the prepared dyes. As a result, both dyes exhibited the superior solubilities and satisfactory light absorption properties. Also, monofluorotriazine-vinylsulfone bifunctional dyes showed moderate sensitivity to alkalinity and proper kinetic index values compared with the monochlorotriazine-vinylsulfone bifunctional dyes and the imported dyes. The results indicated monofluorotriazine-vinylsulfone bifunctional structure of the dye is suitable for cold pad batch dyeing.

Fault Detection and Diagnosis Simulation for CAV AHU System (정풍량 공조시스템의 고장검출 및 진단 시뮬레이션)

  • Han, Dong-Won;Chang, Young-Soo;Kim, Seo-Young;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.10
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    • pp.687-696
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    • 2010
  • In this study, FDD algorithm was developed using the normalized distance method and general pattern classifier method that can be applied to constant air volume air handling unit(CAV AHU) system. The simulation model using TRNSYS and EES was developed in order to obtain characteristic data of CAV AHU system under the normal and the faulty operation. Sensitivity analysis of fault detection was carried out with respect to fault progress. When differential pressure of mixed air filter increased by more than about 105 pascal, FDD algorithm was able to detect the fault. The return air temperature is very important measurement parameter controlling cooling capacity. Therefore, it is important to detect measurement error of the return air temperature. Measurement error of the return air temperature sensor can be detected at below $1.2^{\circ}C$ by FDD algorithm. FDD algorithm developed in this study was found to indicate each failure modes accurately.