• Journal of the Korean Ceramic Society
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• v.41 no.6
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• pp.476-480
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• 2004

AZO (Al-doped ZnO) thin films were deposited on glass by pulsed magnetron sputtering method, and their structural, electrical and optical properties were investigated. XRD patterns showed that a highly c-axis preferred AZO film was grown in perpendicular to the substrate when pulse frequency of 30 ㎑ was applied to the target. Microstructure of thin films showed that the fibrous grain of tight dome shape was grown. The deposition rate decreased linearly with increase of pulse frequency, and the lowest resistivity was 8.67${\times}$10$\^$-4/ $\Omega$-cm for the film prepared at pulse frequency of 30 ㎑. The optical transmittance spectra of the films showed a very high transmittance of 85∼90%, within visible wavelength region and exhibited the absorption edge of about 350 nm. The characteristics of the low electrical resistivity and high optical transmittance of AXO films suggested a possibility for the application to transparent conducting oxides.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.3
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• pp.3-10
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• 1993

As a method to measure the absorbing characteristics of microwave absorber, various microwave measuring method can be used fundamentally. There is, however, a big problem in measuring errors, since the wavelength of microwave such as used for radar is very short. Therefor, this research aimed to design and fabricate a converting adaptor of 20mm .PHI. coaxial tube from a type-N connector to coaxial tube and to use it for evaluating absorption characteristics of microwave absorbor. Furthemore, the measurements of absorbing characteristics and material constants have been perfomed and reviewed, which were carried out by using the coaxial and by using rectangular waveguide, respectively. As a result, the validity of the proposed measuring method has been conformed. In this paper, a preliminary evalua- tion on the characteristics of the electromagnetic wave absorbor for X-band radar designed and fabricated for a laboratory use is performed by reflected power method near to a pratical use. Then for field test by using X-band radar is carried out with real target of $1.2m\times1.2m$ in size. As the result of the above, the usefullness of the designed and fabricated electromagnetic wave absorber in paint type for X-band radar has been confirmed.

• Textile Coloration and Finishing
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• v.21 no.3
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• pp.10-18
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• 2009

Dyeing process of the natural indigo powder onto ramie and silk fabrics was investigated by using glucose and calcium hydroxide as a reducing system. Effect of reduction and dyeing conditions such as temperature and time of reduction/dyeing, and concentrations of glucose and calcium hydroxide on the dyeing process were explored. Indigo powder was obtained by drying the conventional niram paste in an oven at $50^{\circ}C$. Color strength of the dyed fabrics was evaluated by K/S value measured at the wavelength of maximum absorption(${\lamda}$max). Munsell color coordinates(H V/C) were used to compare fabric colors of ramie and silk. Ramie fabric showed purple-blue color for all the temperature and time. On the contrary, silk fabric showed wide range of color including brown, brown-green, green at the different temperature. With the increase of K/S value, the coordinate of value(lightness) decreased for both of ramie and silk fabrics. The coordinate of hue(shade) changed drastically with the increase of K/S value for silk fabric, compared with that of ramie fabric which showed nearly constant value at the whole range of K/S value. Optimum concentrations of calcium hydroxide were for 6 g/L for ramie and 4 g/L for silk at $60^{\circ}C$ and 50 min. K/S value increased with the indigo concentration. Maximum K/S value was shown at $10{\sim}12$ g/L of glucose concentration. For both of ramie and silk fabrics, the colorfastness of washing and light was lower than that of rubbing. All the colorfastness values were improved with the increase of color strength.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.101-109
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• 2010

The objective of this study is to investigate the characteristics of natural indigo dyeing of cotton fabric. Reduction and dyeing were carried out by one-step process using an infrared dyeing machine at the liquor ratio of 1:100, and subsequently oxidation and washing in water were followed. Dye uptake was increased with the increase of indigo concentration. Over the full range of dyeing tests, the dyeing condition was optimized to $40^{\circ}C$ for 40min. For most of dye concentrations, the cotton fabrics showed mainly PB color. Maximum K/S value was shown at 4g/L of sodium hydrosulfite concentration and the color strength increased with the increase of dye concentration. Value(lightness) decreased with the increase of dye uptake irrespective of mercerization or reduction method, while the mercerized cotton showed two times higher dye uptake than the untreated cotton. Whereas hue of the untreated cotton showed large decrease of P character(5.6~3.5 PB) with the increase of dye uptake, that of the mercerized cotton increased P character(4.7~5.5 PB). Irrespective of mercerization, value and chroma decreased with the increased of dye uptake. In addition, the untreated showed lower chroma than the mercerized cotton. In the case of traditional reduction, hue of the untreated cotton was changed very little with the increase of dye uptake. For hydrosulfite reduction, P character decreased with the increase of dye uptake. The difference of hue value was small with the change of reduction method(hydrosulfite reduction or traditional fermentation). Color character was not influenced by the changed maximum absorption wavelength. Washing fastness showed 4~4/5 shade change rating without any staining. And dry rubbing fastness was good at low color strength. The bacterial reduction ratios of dyed cotton fabric were also increased.

• Applied Chemistry for Engineering
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• v.2 no.1
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• pp.70-76
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• 1991

Water soluble poly(sulfonated styrene-co-acrylic acid) was polymerized with sulfonated styrene and acrylic acid in the presence of silver sulfate at $99^{\circ}C$ for 4 hrs. The complex formation of poly(sulfonated styrene-co-acrylic acid) with Cu(II) was carried out. The maximum absorption wavelength of the poly(sulfonated styrene-co-acrylic)-Cu(II) system at different pH values was observed at 274 nm and 295 nm. The reduced viscosity of the poly(sulfonated styrene-co-acrylic acid)-Cu(II) complex were measured in the various pH ranges. The formation constants and stability constants of poly(sulfonated styrene-co-acrylic acid)-Cu(II) complex were calculated from Bjerrum method. The changes of enthalpy, free energy and entropy in the above reaction were determined by Ringbom method.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1511-1511
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• 2001

Energy content, expressed as calories per gram, is an important part of the evaluation and marketing of foods in developed countries. Currently accepted methods of measurement of energy by U.S. food labeling legislation include measurement of gross calories by bomb calorimetry with an adjustment for undigested protein and by calculation using specific factors for the energy values of protein, carbohydrate less the amount of insoluble dietary fiber, and total fat. The ability of NIRS to predict the energy value of diverse, processed and unprocessed cereal food products was investigated. NIR spectra of cereal products were obtained with an NIR Systems monochromator and the wavelength range used for analysis was 1104-2494 nm. Gross energy of the foods was measured by oxygen bomb calorimetry (Parr Manual No. 120) and expressed as calories per gram (CPGI, range 4.05-5.49 cal/g). Energy value was adjusted for undigested protein (CPG2, range 3.99-5.38 cal/g) and undigested protein and insoluble dietary fiber (CPG3, range 2.42-5.35 cal/g). Using a multivariate analysis software package (ISI International, Inc.) partial least squares models were developed for the prediction of energy content. The standard error of cross validation and multiple coefficient of determination for CPGI using modified partial least squares regression (n=127) was 0.060 cal/g and 0.95, respectively, and the standard error of performance, coefficient of determination, bias and slope using an independent validation set (n=59) were 0.057 cal/g, 0.98, -0.027 cal/g and 1.05 respectively. The PLS loading for factor 1 (Pearson correlation coefficient 0.92) had significant absorption peaks correlated to C-H stretch groups in lipid at 1722/1764 nm and 2304/2346 nm and O-H groups in carbohydrate at 1434 and 2076 nm. Thus the model appeared to be predominantly influenced by lipid and carbohydrate. Models for CPG2 and CPG3 showed similar trends with standard errors of performance, using the independent validation set, of 0.058 and 0.088 cal/g, respectively, and coefficients of determination of 0.96. Thus NIRS provides a rapid and efficient method of predicting energy content of diverse cereal foods.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1254-1254
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• 2001

Near infrared spectroscopy (NIRS) was applied to determination of the lipid content of compost during compost fermentation of tofu(soybean-curd) refuse. The reflected rays in the wavelength range between 800 and 2500 nm were measured at 2 nm intervals. The absorption of lipid observed at 4 wavelengths, 1208, 1712, 2312 and 2352 nm on the second derivative spectra. To formulate a calibration equation, a multiple linear regression analysis was carried out between the near-infrared spectral data and on the lipid content in the calibration sample set (sample number, n=60) obtained using a Soxhlet extraction method. The calibration equation for prediction of lipid, the value of the multiple correlation coefficient (R) was 0.975 when using the wavelengths of 1208 and 1712nm. To validate the calibration equation obtained, the lipid content in the validation sample set (n=35) not used for formulating the calibration equation were calculated using the calibration equations, and compared with the values obtained using the Soxhlet extraction method. Good agreement were observed between the results of the Soxhlet extraction method and those values of the NIRS method. The simple correlation coefficient (r) and standard error of prediction (SEP) were 0.964 and 0.815 %, respectively. Then, the NIRS method was applied to a compost fermentation in which the time course the lipid content were measured and good results were obtained. The study indicates that NIRS is a useful method for process management of the compost fermentation of tofu refuse.

• Fashion & Textile Research Journal
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• v.11 no.6
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• pp.953-960
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• 2009

The natural dyeing of fabrics with myrobalan extract was investigated. After dyeing of silk, cotton and rayon with myrobalan extract, the dyeability of myrobalan extract was evaluated with the conditions of concentration, temperature, time, repeat-numbers, pH, mordants variables, the changes of dyeability and surface colors by methods of mordanting and color fastness. The wavelength of maximum absorption of the colored solution from myrobalan extract appeared at 272 nm. Therefore, the substance of myrobalan extract was verified as tannin dyes. The optimum dyeing of fabrics was carried out at 30%(o.w.f) dye concentration. Silk fabrics dyed with myrobalan extract showed the highest K/S value at the temperature of $80^{\circ}C$ when it was dyed for seventy minutes, while cotton and rayon fabrics showed the highest K/S value at the temperature of $90^{\circ}C$ when they were dyed for seventy minutes and thirty minutes, respectively. Dyeing operation was carried out in acidic dyebath of pH 3. The K/S value of silk fabric was higher in pre-mordant stage than in post-mordant, while the K/S values of cotton and rayon fabrics were higher in post-mordant stage. The surface colors of dyed fabrics were different according to used mordants: Al and Cu mordanted fabrics were dyed in yellowish colors, while Fe mordanted fabric was dyed in khaki-black color. Light-fastness of the color fastness was improved in Fe-mordant. Washing-fastness was relatively good, and dry cleaning-fastness of dyed fabrics was excellent.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.338-343
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• 2003

The characteristics of the pigments extracted from grains of the colored barley varieties Ab2231, Mozzimugi, Lion, and Hogye 4 were studied. Extraction of the pigments from powder (80 mesh) of the barley grains was most efficient in 80% ethanol containing 1.0% HCI for 1 hr at $60^{\circ}C$. The pigments were also stable in 80% ethanol containing 1.0% HCI. Depending on the absorption spectra, maximal peak wavelength, and the ratio of $A_{440}/A_{max}$, the varieties were separated into two groups, colored naked barley (Ab2231 and Mozzimugi) and colored covered barley (Lion and Hogye 4).

• Journal of Fashion Business
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• v.11 no.1
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• pp.136-148
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• 2007

African marigold is a common plant easily available in many flower beds. It has been reported as a practical and prospective resource of dyes since the dyes can be extracted from their bodies as well as petals. In this research, cotton and ramie fabrics which are made from natural cellulose were dyed using the extract of the African Marigold which is a variety of marigold. Dyeing tests were carried out under different pH of the dye solution and mordants. Dyeability was evaluated by examining and measuring surface color, K/S value, and the changes in the maximum absorption wavelength. The probability of improving dyeability was investigated by pre-mordanting with pre-treated chitosan. For the dyeing with marigold extract, the color tone did not differ by pre-mordanting and non-mordanting. Reaction with post-mordanting was excellent, which was colored in various yellow series. The best dyeability was achieved in dye solution of pH 6.5-7.0 which is not conditioned. The largest K/S value and color difference were obtained in tin mordanting. The dye uptake was greatly increased in chitosan pre-treated mordanting compared with the post-mordanting without chitosan pre-treatment. Due to its high heat resistance, African Marigold extract is easy for dye extraction and dyeing, and its dyeability is excellent for natural cellulose fibers. Also, colorfastness was proved to be practically usable.