• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1285-1285
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• 2001

For NIR measurements of papers normally diffuse reflectance accessories are used which can provide a large sampling area. The in-line process control FT-NIR spectrometer MATRIX-E enables the contactless measurement of paper samples of low silicone coat weights on label-stocks in a paper converting factory. For this study concentrations of silicone between 0 and 2 g/$m^2$ on various paper substrates were included in a quantitative method. The aim was to achieve an absolute value for the deviation from the target value of 1 g/$m^2$ during continuous movement of the paper with velocities around 400 numinute. Influences from the uncoated paper type due to supplier, color, opacity, area densities, pre-coating as well as different compounds of the agent silicone were investigated and it was found that all these papers can be represented in one PLS-model. Especially the fact that silicone as an element is present in clay coated papers is of no consequence to the measurements with MATRIX-E. Moreover during in-line installations the variation of the moisture contents in the moving paper due to variable machine velocities as well as the reflecting material of the cylinder have to be considered. It is shown that the result of the in-line calibration has the same prediction ability compared to lab scale results(Root Mean Square Error of Cross-Validation RMSECV = 0.034 g/$m^2$).

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1193-1193
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• 2001

For NIR measurements of papers normally diffuse reflectance accessories are used which can provide a large sampling area. The in-line process control FT-NIR spectrometer MATRIX-E enables the contactless measurement of paper samples of low silicone coat weights on label-stocks in a paper converting factory. For this study concentrations of silicone between 0 and 2 g/㎡ on various paper substrates were included in a quantitative method. The aim was to achieve an absolute value for the deviation from the target value of 1 g/㎡ during continuous movement of the paper with velocities around 400 m/minute. Influences from the uncoated paper type due to supplier, color, opacity, area densities, pre-coating as well as different compounds of the agent silicone were investigated and it was found that all these papers can be represented in one PLS-model. Especially the fact that silicone as an element is present in clay coated papers is of no consequence to the measurements with MATRIX-E. Moreover during in-line installations the variation of the moisture contents in the moving paper due to variable machine velocities as well as the reflecting material of the cylinder have to be considered. It is shown that the result of the in-line calibration has the same prediction ability compared to lab scale results (Root Mean Square Error of Cross-Validation RMSECV = 0.034 g/㎡).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.63-69
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• 2004

It is of great interest to enhance mixing performance in a microchannel in which the flow is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved in this laminar flow regime. In this regard, we present a new chaotic passive micromixer, named Barrier Embedded Micromixer (BEM), of which the mixing mechanism is based on chaotic flows. In BEM, chaotic flow is induced by periodic perturbation of the velocity field due to periodically inserted barriers along the channel wall while a helical type of flow is obtained by slanted grooves on the bottom surface of the channel in the pressure driven flow. To experimentally compare the mixing performance, a T-microchannel and a microchannel with only slanted grooves were also fabricated. All microchannels were made of PDMS (Polydimethylsiloxane) from SU-8 masters that were fabricated by conventional photolithography. Mixing performance was experimentally characterized with respect to an average mixing intensity by means of color change of phenolphthalein as pH indicator. It was found that mixing efficiency decreases as Re increases for all three micromixers. Experimental results obviously indicate that BEM has better mixing performance than the other two. Chaotic mixing mechanism, suggested in this study, can be easily applied to integrated microfluidic systems , such as Micro-Total-Analysis-System, Lab-on-a-chip and so on.

• Journal of Conservation Science
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• v.17 s.17
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• pp.65-72
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• 2005

To preserve straw sandals excavated at Goongnamji site, this study examined the weight change rate by applying the methods of Primal MC-76 and vacuum freeze-drying used mostly as a earth-layer hardening material among PEG and acrylic resin, which are applied widely for preservation of waterlogged archaeological wood, as a means to preserve plant-based cultural properties along with the examination of the subject material. An experiment was also performed on moisture absorption after treatment. The materials of sandals were identified as Typha spp. The weight change experiment revealed that the vacuum freeze-drying after being treated with PEG 2-Step showed the most stabilized changes in weight, while it offered the smallest change in color as well.

• Journal of the Korean Applied Science and Technology
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• v.2 no.1
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• pp.19-23
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• 1985

In order to know the quality changes of the fat and oil foods packed in plastics film by the sunlight, we examined the sunlight transmitting rate by the kind of films and measured the acid value and peroxide value according to it. The results obtained were as follows : 1. The sunlight transmitting rate of various films was explained especial permeability under the wavelength of less than 300nm, but it marked a regular form under that of more than 30nm. 2. The vacuum evaporation film with aluminum on the polyester shuts off most of the sunlight, therefore, it has the best effect that keeps the fats and oils off rancidity. 3. The sunlight transmitting rate of the white color printing film drops about 80% as compared with not printing. 4. The preventive power against the rancidity of fats and oils is PET/Al, PET, PE, nylon and OPP film in that order. The changes of peroxide value and acid value were approximately the same as that of the sunlight transmitting rate.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.669-675
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• 2009

A study has been made on the preparation of liquid resin of non-solvent and non-discoloration type for replacement of the soft PVC at room temperature. A new synthetic process was developed by structure-control design of polyurethane synthesis using pre-polymer and polyols as curing agent. The optimum recipe was made according to macro-glycols, molecular weight and reaction conditions, and the final products indicated that the mechanical properties such as tensile strength, tear strength and flexibility was very excellent than PVC products. Also, viscosity, hardness and color operations of the final products can be controlled by this system. And yellowing property by UV and NOx gas was improved from the various additive experiment.

• Journal of Technologic Dentistry
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• v.29 no.1
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• pp.35-48
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• 2007

The purpose of this study was to evaluate shade selection using conventional visual assessment in vivo natural teeth and porcelain-fused-to-metal (PFM) crown. Maxillary central incisors, lateral incisors and canines of one hundred twenty four college women were used as vivo natural teeth. Fifty one PFM crown for maxillary central incisor fabricated by dental laboratory were used as experimental materials. Using Vitapan Classical Shade Guides, shade selection of natural teeth was measured by each college woman and shade selection of PFM crown was measured by three ceramists with more than ten years career. Both natural teeth and PFM crown shade selection were measured through Shade Eye-Ex. From the shade selection comparing, following results were obtained. The results were as follows: 1. The shade matching identification of natural teeth between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 27.4% in maxillary central incisor, 13.7% in lateral incisor and 18.5% in canine. 2. Among the shade selection of PFM crown by three ceramists, the shade evaluation of three ceramists were same only in ten cases. In twenty case, those of two ceramists were same. 3. The shade matching identification of PFM crown between the shade selection using Vitapan Classical Shade Guides and the shade selection using Shade Eye-Ex was 38.6% in average. These results suggest that the shade selection using conventional visual assessment should be dealt with care in clinic and need a credible method for shade matching color.

• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.121-128
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• 2020

Purpose: This study aimed to investigate the effects of the sintering conditions of zirconia core on the adaptability. Methods: Ten specimens of each of commercial brand of zirconia(Razor 1100, U&C international, Seoul, Korea) were made and sintered under three different conditions. Specimens were divided into three subgroup(n=10) and sintered with various total time(1hr, 3hr, 9hr) at the maximum temperature(1500℃). The digitized data was superimposed with 3D inspection software to quantitatively obtain the adaptation of a zirconia core, and visual differences were confirmed with a color map. The root mean square(RMS) values of group were statistically analyzed with one-way ANOVA(α=0.05). Results: The overall adaptation of the zirconia cores were as follows; ss-1hr: 36.18±5.2㎛, ss-3hr: 39.55±3.9㎛, cs-9hr: 46.62±4.3㎛. They were statistically significant differences between groups for adaptation(p<0.05). Conclusion: Based on the results of this study, it could be considered that sintering condition of 1500℃ and 1~3 hour is recommended for the better marginal and internal fit. Speed sintering can be widely utilized to fabricate zirconia prothesis as the properties of those almost are to dentistry uses.

• Fashion & Textile Research Journal
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• v.8 no.5
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• pp.562-570
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• 2006

Knit industry requires versatile knit designers who have to control whole process such as material select, color, type of machine, technique, structure and shape. In other words, knit designers urgently need to interplay between technology and design aesthetics. It becomes essential to learn and master basic principles of knitting in order to design and develop effectively for innovative knitwear design. The main purpose of this study is to show fresh methodology through examining the various applications of 'Stitch transfer knitting structure' used in women's knitwear design development. Stitch transfer knitting structure is one of the most popular techniques among various basic knitting methods. Eight knitwears were designed and produced with various types of formative applications which differ from existent stitch transfer knitwears of flat and simple style in the market. These are produced by computer knitting machine 'Shima Seiki 122S' and programmed by 'Knit CAD' software. Among various basic stitch transfer pattern, 'Leaf' pattern is selected as a most effective example for this study. This fabric applied to collar, sleeves, body pattern and accessories as formative decoration. It is expected that this study of methodology helps to get open mind and to indicate possibility to develop and show creative and innovative knitwear and knitted textile design.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.302-307
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• 2010

This study aims to synthesize emerald-green malayaite pigments using $CaCO_3$, $SiO_2$, $SnO_2$ and $V_2O_5$. For this purpose, the optimum composition is $CaV_{0.25}Sn_{0.687}SiO_5$ and heating condition is at $1250^{\circ}C$ for 6 h of soaking time. The samples were characterized by X-ray diffraction (XRD), the Fourier Transform Infrared Spectrometers(FT-IR), the Raman Spectrometer, Scanning Electron Microscope(SEM) and the UV/Vis spectroscopy. The substituted V ion for Sn was observed to be quadrivalence. The analytical results of the synthesized pigment showed the tetragonal crystal, a typical form of Malayaite, and the particle size to be approximately $5{\sim}10\;{\mu}m$. The color in lime glaze added 12 wt% pigment was emerald green, and CIE Lab parameters are $L^*=67.73$, $a^*=-12.39$ and $b^*=9.28$.