• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.3
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• pp.46-52
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• 2002

To produce the raw material used for printing and writing paper or high quality tissue, MOWs that were consisted of white ledger, colored ledger and old newspaper were bleached with EoP and EoPY(FAS) method, the EoP bleaching process gave the improvement in brightness and a high color removal efficiency. Especially, MOW B(initial brightness: 59.1％ ISO) that contained much old newspaper showed the higher bleaching efficiency than those of MOW A(initial brightness: 68.3%). After EoPY(FAS) bleaching, MOW's brightness was increased from 68.3% ISO to 84.3∼84.0% ISO, and from 59.1% ISO to 78.7∼79.2% ISO, respectively. Also the tensile and burst index of bleached pulps decreased by 10∼30%. The tear index slightly decreased or halted at the same range as unbleached pulps.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.1-8
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• 2012

This study was carried out to explore optimum use of the products generated from the National Forest Management Operation (NFMO) as raw materials for kraft pulp. First of all, different wood species from NFMO were randomly mixed, and then they were used to make kraft pulp under the specified condition. All kraft pulps made from the mixed species displayed equal physical properties to those from foreign wood chips used in Moorim P&P Co. Ltd. For optical properties, most of the unbleached pulps had high brightness but the pulp made from wood species containing chestnut tree showed the lowest brightness due to its high kappa number. Finally, the products from NFMO had little negative effects on the properties of kraft pulps. This means that they could be used as complementary raw materials for kraft pulps with foreign wood chips.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.361-364
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• 2006

Generally, aging of paper is evaluated by folding endurance and degree of yellowing. It was known as that lignin, hemicellulose and metallic ion affect yellowing of mechanical or chemical pulps. Among these elements, especially, the study of hemicellulose that affect at yellowing of pulp is insufficient. In this study, we examined into the influence that glucuronoxylan or glucomannan and metallic ion($Cu^{2+},\;Fe^{2+},\;Fe^{3+},Mn^{2+}$) residued in pulp get each or when mixed at yellowing. Filter paper was treated with each metallic ion, glucuronoxylan and the mixture of glucuronoxylan and metal ions, and brightness and CIE $L^*a^*b^*$ was measured after accelerated aging. As the results of measurements, the filter paper processed by 10% glucuronoxylan was dropped 2-3% on the brightness after accelerated aging for 24 hours. Also, the filter paper treated with glucuronoxylan and $Fe^{2+}$ was dropped 7% on the brightness.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.15-20
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• 2022

Colours are primarily composed of three properties - hue, brightness, and saturation, However, each property of colour is not independently visually recognised. Previous studies on saturation and brightness found that brightness was sensed differently depending on the degree of purity of the saturation; however, most of the psychophysical experiments used subtractive mixing. Therefore, fundamental research on colour perception based on display is needed. In this study, we conducted a psychophysical experiment and to investigate the visual characteristics of saturation and brightness based on a display with a self-luminous system. After selecting a certain brightness in the additive-mixed display, the experiment was conducted by adjusting the saturation of the main colours. Thus, by analysing the experimental results, we determined whether the results were the same as ones from subtractive mixing and whether the data are meaningful for the characteristics of colour perception. We also suggested future research directions.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.2
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• pp.8-16
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• 2001

To manufacture toilet tissue with ONP (old newspaper), the effect of fractionation fiber (R150, R100, R70 mesh) and bleaching(P, PY), blending (70/30) with MOW(mixed office wastepaper) or WL(white ledger) and the addition of softener on the optical and mechanical properties were studied. Considering the pulp yield, brightness and strengths, fibers of R100 mesh fraction were proper to be produced to toilet paper from ONP. This pulp showed the pulp yield of 76.8%, brightness of 50.2% ISO and tensile index of 21.1 Nm/g. By the bleach with P and PY stages, the brightness of the pulps increased up to 60.3% ISO and 61.8% ISO, respectively. When blended with MOW (57.3% ISO) or WL (76.2% ISO), the brightness of the former increased up to 58.5% ISO, the latter up to 63.6% ISO. The strengths of pulp blended with WL were higher than those of fractionated pulp from 100% ONP, however there was no difference in strengths between fractionated pulp and blended pulp wth MOW. While the addition of softener improved the softness of paper, but it decreased strengths of pulp and extended dispersing time in water.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.2
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• pp.58-67
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• 2001

MOW (Mixed Office Waste) mainly consisted of photocopied paper is being recycled to produce tissue or fine paper products. Toner particles that are fused and set on paper surface in photocopying process turns into large and plate-shaped particles after repulping which prevents them to be removed effectively in flotation deinking. The immediate purpose of this study is to find the effective deinking technology that increases the recycling potential of photocopied papers for manufacturing tissue and fine paper products. In this study the effects of pulping temperature and the type of hydrophobic groups of nonionic surfactants on the deinking efficiency of photocopied paper has been investigated. Particle size distribution of the toner particles after pulping and flotation, brightness, yield and ash removal were investigated. The size of toner particles after pulping increased as the pulping temperature was increased. When pulping at the low temperature finer toner particles were generated, however, greater amount of toner particles was found to attach to the fiber. When the pulping temperature was greater than Tg of the toner, the amount of coarse hairy particles increased. When nonionic surfactants with a double bond in hydrophobic groups were used, toner removal efficiency, brightness and ash removal were increased. As the addition level of surfactant was increased, yield decreased rather sharply without improving brightness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.23-29
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• 2016

Effects of cationic polyvinylamine (PVAm) dry strength agent on effectiveness of optical brightening agent (OBA) during fine papermaking and the mechanism for brightness reduction of paper by PVAm was investigated by UV/Vis spectroscopy and turbidity measurement of OBA solution with PVAm. It was shown that PVAm reduced brightness of paper while opacity was not varied and tensile strength of paper was increased. Tetra-type OBA solution showed the peaks around the wavelength of 280 nm and 330 nm and the increase in the OBA concentration increased the UV absorbance in all wavelength. Addition of PVAm into the OBA solution decreased the UV absorbance at 280 nm. Turbidities of OBA and PVAm solutions were close to zero, respectively, while the turbidity value increased for the mixed solution of OBA and PVAm in various mixing ratios and the highest value was obtained when the mixing ratio of PVAm and OBA was 5:5, meaning that cationic PVAm formed complex with anionic OBA. In conclusion, cationic PVAm could form a complex with anionic OBA and that reduced UV absorbance, resulting in the reduced brightness of paper.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.55-63
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• 2013

Purpose: The present study aimed at image processing methods for automatic cell pattern recognition and morphological analysis for tissue engineering applications. The primary aim was to ascertain the novel algorithm of adaptive brightness correction from microscopic images for use as a potential image analysis. Methods: General microscopic image of cells has a minor problem which the central area is brighter than edge-area because of the light source. This may affect serious problems to threshold process for cell-number counting or cell pattern recognition. In order to compensate the problem, we processed to find the central point of brightness and give less weight-value as the distance to centroid. Results: The results presented that microscopic images through the brightness correction were performed clearer than those without brightness compensation. And the classification of mixed cells was performed as well, which is expected to be completed with pattern recognition later. Beside each detection ratio of hBMSCs and HeLa cells was 95% and 92%, respectively. Conclusions: Using this novel algorithm of adaptive brightness correction could control the easier approach to cell pattern recognition and counting cell numbers.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.4
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• pp.320-326
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• 2014

In this paper, the new smart dimming algorithm which is mixed with PWM and PAM control method is proposed for reducing the power consumption of LED TV Backlight. The proposed technique is using the curve characteristics of LED forward voltage and current which is proportionally changing LED forward voltage as changing LED forward current. Therefore, each PWM and PAM control method has different LED forward voltage and current in the same brightness condition. The PWM control method adjusts the brightness of LED TV Backlight by only varying the duty ratio of PWM and constantly sustaining the amplitude of LED forward current and voltage. So, the level of LED forward current and voltage in the PWM control method is relatively high and constant regardless of duty ratio of PWM. On the other hand, the PAM control method adjusts the brightness of LED TV Backlight by directly varying the level of LED forward current. So, the level of LED forward current and voltage in the PAM control method is lowered according to the brightness level. For the above-mentioned reason, the PAM control method has the advantage of reducing the total power consumption of LED TV Backlight at the brightness condition of below 100%, compared with PWM control method. By implementing this characteristic to LED driver circuit with control algorithm in MCU, the power consumption of LED TV Backlight can expect to be reduced. The effectiveness of the proposed method, new smart dimming algorithm, CPWAM(=Conditional Pulse Width Amplitude Modulation), has been verified by experimental results.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.1-6
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• 2010

Paper industry in Korea produces 14 million tons of paper and 1.3 million tons of sludge per year. Most of them has been treated by incineration, landfilling or ocean dumping. The sludge recycling to minimize the impact on the environment, so its importance is highlighted. In this study, in order to develop a new way of recycling the sludge, it was calcined and the recycled ash was tried to use as papermaking filler. Concerning the yield of calcium carbonate and the brightness and the rheology of the recycled calcination sludge, the optimum calcination conditions were found to be $600^{\circ}C$ and 12 hours. The sludge ash itself was not suitable for papermaking due to its color and low brightness. Thus the ash from the sludge was first mixed with a commercial filler and then utilized for papermaking. The effect of the increased hardness after high temperature treatment on wire abrasion was confirmed.