• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.335-336
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• 2003

The synthesis of poly(trimethylene terephthalate) (PTT), whose application is being expanded very rapidly to new apparel and carpet materials, was investigated by melt condensation polymerization using 1,3-propanediol (PDO) and terephthalic acid (TPA). No catalyst was used in the 1st step reaction (esterification), but tetrabutyl titanate(TBT) was used as a polyesterification catalyst ranging from 25 to 75 ppm based on the weight of TPA used in the 2nd step reaction (polyesterification). The molar ratio of PDO to TPA was set as 2.2:1. The effect of reaction conditions on the color and intrinsic viscosity of the final product was investigated. (omitted)

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1009-1011
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• 2004

In the present work a very simple, sensitive and selective spectrophotometric method for the determination of nitrite in micellar media is described. The method is based on the color reaction of nitrite with p-nitroaniline in the presence of diphenylamine in acid media. In order to remove the extraction step, Triton X-100, a non-ionic surfactant was used as micellar media. The optimum reaction conditions such as acid concentration, reagents concentration and effect of time have been studied and the analytical characteristics of the method such as limit of detection, linear range and molar absorptivity have been obtained. The interference of some anions and cations was also tested. The method was applied to the determination of nitrite in real samples.

• YAKHAK HOEJI
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• v.3 no.1
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• pp.48-50
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• 1957

The micro-assay methods of vanillin have been shown quite few, though several methods have been introduced for determination. A new sensitive micro-determination of vanillin, applying the yellow color reaction of vanillin and anillin, is shown in this paper. The absorption maximum of the yellow coloring matter, 4-Oxy-3-methoxy-henzal aniline, was 435 mu. The one dimensional ascending paper chromatographic method is applyed for isolation of vanillin from the mixed sample. The microdetection of vanillin is studied only in this paper. Vanillin was detected by the yellow spot on paper trip by the coloring reagent of aniline after several hours paper strip chromatographic at the following condition; paper strip ................ 2.5 X 35cm Whatman Filter Paper No.2 developing Solvent ......... petroleum-benzene-methanol n-butanol-water coloring agent ............. aniline. The Rf-value on petroleum benzene and methanol was 0.63 and that on n-butanol and water was 0.90. The minimum detectable amount of vanillin by this method was 10 micrograms. It is recommendable, if interference substances as aromatic aldehydes present, that the application of this aniline reaction and Foline Denis reaction on the same paper chromatogram is appreciable.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.241-248
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• 2008

The purpose of the research is to investigate of diesel spray combustion for simultaneously reduction way of NOx and PM. The diesel injection were done into intermediates that are generated by very lean DME HCCI combustion using a RCM. The concentration of intermediate could not be directly measured, so we estimated it by CHEMKIN calculation. Two dimensional spontaneous luminescence images which are created by chemical species reaction at low temperature reaction (LTR) and high temperature reaction (HTR) are captured by using a framing streak camera. Also, combustion events were observed by high-speed direct photography. The ignition and combustion events were analyzed by pressure profiles and the KL values and flame temperatures were analyzed by the two-color method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.117-118
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• 2011

The acid stained agents are able to make remarkably thin colored layers on concrete surfaces and have simple processes for applying them comparably. This study has examined properties of the reaction to acid stained agent and cement hydrate. We've observed that the C-S-W autoclave cured specimens contain less Calcium Hydroxide than the others and create tobermorite of C-S-H system crystalline and concluded that the reactions of acid stained agent become slowdown under C-S-W and cause light colors of specimens.

• Journal of the Korean Ceramic Society
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• v.54 no.3
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• pp.217-221
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• 2017

Improvement studies of existing phosphors are needed for use in light emitting diodes (LEDs). Among the phosphors discovered recently, the SLA ($SrLiAl_3N_4:Eu^{2+}$) is a phosphor that has a narrow width. It is now known as a good red phosphor that meets the industry's needs for warm white (color temperature ranging from 2700 to 4000 K) and high CRI (> 80). However, SLA phosphors are obtained from difficult synthetic methods. All commercially available phosphors should be derived from the general solid state synthesis method. The phosphors produced by difficult synthetic methods will inevitably fall out of price competitiveness and will be scrapped. This study succeeded in synthesizing SLA ($SrLiAl_3N_4:Eu^{2+}$) phosphors by using a general solid phase synthesis method based on the reaction energy obtained from DFT calculations. As a result, we found an optimal solid state synthesis method for SLA phosphors.

• Textile Coloration and Finishing
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• v.19 no.5
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• pp.37-40
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• 2007

The electrostatic layer-by-layer technique provides a convenient way to control the construction of ultrathin films at nano-scale ranges and can be easily obtained. It can be also applicable to fiber substrate with dye compounds. We have fabricated multilayer dye films using diazonium resin and three couplers, which are prepared by self-assembly approach. This method is based on layer-by-layer deposition using electrostatic attraction between oppositely charged ions. Beside, the diazo coupling reaction proceeded to form azo dye layer on the PET fibers the same time. The corresponding results of the multilayer films have been discussed on the level of color strength (K/S).

• Korean Journal of Food Science and Technology
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• v.21 no.4
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• pp.480-485
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• 1989

Changes of color intensity and components during browning reaction of water extracts from white tail ginseng were investigated. Temperature dependence was described by the Arrhenius relationship with an activation energy of 16kcal/mole. Temperature sensitivities$(Q_{10}\;value)$ for water extracts of ginseng was 1.90 between $70^{\circ}C\;and\;80^{\circ}C$, 1.57 between $80^{\circ}C\;and\;90^{\circ}C$ and 1.46 between $90^{\circ}C\;and\;100^{\circ}C$. pH value of the solution treated at $90^{\circ}C\;and\;100^{\circ}C$ slightly increased with an increase in reaction time. Among ginseng saponins ginsenoside-Re was most unstable against heat-treatment, white diol group saponins were more stable against heat-treatment. Hydrogen donating activity (reducing activity for ${\alpha},\;{\alpha}'-diphenyl-{\beta}-picrylhydrazyl$) and 3,5-dinitrosalicylic acid(DNS) positive substances of browning reaction products increased in proportion to the length of browning reaction time and temperature, whereas folin positive substances decreased by heat-denaturation of ginseng protein at initial reaction time and then increased thereafter.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.01a
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• pp.277-279
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• 2013

본 논문에서는 광학적 방법을 이용하여 정색반응을 정량적으로 측정할 수 있는 방법을 제시한다. 정색반응은 발색, 변색의 현상을 일으키는 화학 변화로 시료 용액에 시약을 더하여 특수한 빛을 나타내게 하여, 물질을 정성적으로 검출하는데 이용된다. 하지만 정색반응 결과로 나타난 색상은 사람마다 색구별이 다르므로 정확한 양을 알 수는 없다. 본 연구에서는 시료의 양에 따라 색상 변화의 미세한 차이를 PICkit Serial Analyzer를 사용하여 색상을 수치화하여 시료의 양에 따른 색의 변화를 정량적으로 측정하였다.

• International Journal of Concrete Structures and Materials
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• v.18 no.2E
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• pp.125-132
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• 2006

Waste glass has been increasingly used in industrial applications. One shortcoming in the utilization of waste glass for concrete production is that it can cause the concrete to be weakened and cracked due to its expansion by alkali-silica reaction(ASR). This study analyzed the ASR expansion and strength properties of concrete in terms of waste glass color(amber and emerald-green), and industrial by-products(ground granulated blast-furnace slag, fly ash). Specifically, the role of industrial by-products content in reducing the ASR expansion caused by waste glass was analyzed in detail. In addition, the feasibility of using ground glass for its pozzolanic property was also analyzed. The research result revealed that the pessimum size for waste glass was $2.5{\sim}1.2mm$ regardless of the color of waste glass. Moreover, it was found that the smaller the waste glass is than the size of $2.5{\sim}1.2mm$, the less expansion of ASR was. Additionally, the use of waste glass in combination with industrial by-products had an effect of reducing the expansion and strength loss caused by ASR between the alkali in the cement paste and the silica in the waste glass. Finally, ground glass less than 0.075 mm was deemed to be applicable as a pozzolanic material.