• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.86-92
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• 2004

This research was carried out to examine the ethylene gas adsorption and preservation life of white charcoal boards for packaging. Two types of white charcoal board were made of #40-60 charcoal particles and mixed charcoal particles with PVA and MDI resin by wet process. For not only beauty effect but also avoiding stain from touching, white charcoal boards were overlaid with two kinds of overlay material, thin printed paper and non woven fabric. A charcoal board adsorbed ethylene gas much more than the paper and even white charcoal itself. There was no difference between two board types, between overlay treatments, and between overlay materials. Gray mold growth of strawberry arised after 2 days in a paper box and after 4 days in a white charcoal board. Preservation life of white charcoal board box was approximately twice more than that. of a paper box. There was no difference in the ability of keeping freshness between two board types, between overlay treatments, and between overlay materials.

• Journal of the Korean Society of Clothing and Textiles
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• v.39 no.1
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• pp.121-132
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• 2015

All aspects of clothing, including color, are a visible form of expression that carries invisible value. The purpose of this work is to study the expression of resistance in the white Hanbok in modern culture, specifically after the 1980s. Koreans have traditionally revered white color and enjoyed wearing white clothes. In Korea, white represents simplicity, asceticism, sadness, resistance against corruption, and the pursuit of innocence. This paper looks at: (i) the universal and traditional values of the color white, (ii) the significance of traditional white Korean clothing, (iii) the resistance characteristics of white in traditional Korean clothes, and (iv) the aesthetic values of white Hanbok. The white Hanbok often connotes resistance when it is worn in modern Korea. It is worn in folk plays, worn by shamans as a shamanist costume, worn by protestors for anti-establishment movements, and worn by social activists or progressive politicians. The fact that the white Hanbok has lost its position as an everyday dress in South Korea (instead symbolizing resistance when it is worn) is an unusual phenomenon. It shows that the white Hanbok, as a type of costume, is being used as a strong means of expression, following a change in the value of traditional costumes as it take on an expressive function.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.2
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• pp.115-123
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• 2019

White-box cryptography is an implementation technique in order to protect secret keys of cryptographic algorithms in the white-box attack model, which is the setting that an adversary has full access to the implementation of the cryptographic algorithm and full control over their execution. This concept was introduced in 2002 by Chow et al., and since then, there have been many proposals for secure implementations. While there have been many approaches to construct a secure white-box implementation for the ciphers with SPN structures, there was no notable result about the white-box implementation for the block ciphers with Feistel structure after white-box DES implementation was broken. In this paper, we propose a secure white-box implementation for a block cipher SEED with Feistel structure, which can prevent the previous known attacks for white-box implementations. Our proposal is simple and practical: it is performed by only 3,376 table lookups during each execution and the total size of tables is 762.5 KB.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.1-8
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• 2006

In this study a process simulation method was used to analyze the accumulation phenomena of anionic starch in the process white water as the closure level of a fine paper making process is increased. A pilot paper machine was used as a model process. Dynamic simulations of the influence of white water usage ratio and uncoated broke addition ratio on the variation of process variable was monitored as a function of time. Results from the dynamic simulations showed that the volume of reservoirs affected the dynamic behavior of the process. The dynamic behavior of flow rate and dissolved starch concentration in process units were different from each other. The speed of the change of dissolved starch concentration in process units was depend on the starting point of the change of dissolved starch concentration, the length of circulation loop, and the volume of reservoirs.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.1
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• pp.52-58
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• 2015

White ledger usually includes white office paper, computer paper, and copy machine paper. Because these grades need high optical properties, fluorescent whitening agents (FWAs) are widely used in the papermaking process. FWAs are the most powerful and effective chemical used to obtain high CIE whiteness and ISO brightness in papers. The rising demand for white or ultra-white papers has increased the use of FWAs. However, FWAs used in white ledger can restrict its use, even though white ledger is widely used as a raw material in paperboard mills. Therefore, it is necessary to develop methods to control FWAs from white ledger to increase its use in paperboard mills. In this study, the behaviors of disulpho fluorescent whitening agent (D-FWA), tetrasulpo fluorescent whitening agent (T-FWA), and hexasulpho fluorescent whitening agent (H-FWA) during the recycling process were identified as a first step to remove FWAs from white ledger. We prepared four types of papers (dyed with D-FWA, T-FWA, and H-FWA), disintegrated these papers, and made handsheets. This recycling process was carried out three times in a laboratory. After each round of recycling, the hand-sheets' CIE whiteness and fluorescence index were measured, and the distribution of FWAs in the Z-direction was observed using CLSM images. FWA reductions in the model papers were calculated using fluorescence indices as a function of the number of recycling. FWAs in handsheets containing T-FWA and H-FWA decreased linearly as a function of the number of recycling, but D-FWA did not show a significant reduction in the fluorescence index after recycling. T-FWA and H-FWA showed similar distributions of D-FWA after recycling. Therefore, as much T-FWA and H-FWA as possible must be detached in the early processes of papermaking at paperboard mills.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.16-22
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• 2008

The pilot scale ultrasonic deinking was carried out in order to confirm the commercialization possibility of ultrasonic deinking. White ledger was used as a raw material and the results were compared to the results obtained from the conventional deinking. The fraction of smaller ink particle was increased and the improved ink removal efficiency was also obtained by the ultrasonic treatment. The brightness and breaking length of ultrasonic deinked pulp were superior to those of the conventional deinked pulp. Most interesting findings in this study were that the significant improvement in effluent quality and the reduction of chemicals and energy cost were obtained by the ultrasonic deinking.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.24-28
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• 2001

The utilization of wastepaper as a papermaking raw material is everlastingly required for the environmental protection of earth. However the recycling of wastepaper for this purpose cause another problem such as the increasing of the load of wastewater treatment, lower strength properties of paper, and poor printability, etc. The interest in the development of the environmentally friendly deinking technology is increased continuously. Thus, our research team have tried to apply the ozone to the deinking of white ledger and ONP, and obtained the positive results which can be considered as an alternative method for the conventional deinking method. The purpose of this study is to investigate the mechanism of ozone deinking. Styrene acrylate and polystyrene were treated with ozone and measured the change of molecular weight with the GPC. The molecular weight distribution obtained with GPC showed only slight increase by the ozone treatment, and gel formation by the polymerization was observed. Therefore the removal of ink particles with ozone treatment seems to be facilitated by the increase of the brittleness and decrease of adhesive property.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.5-12
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• 2016

White waste papers are very important resources in the paper industry, but their use is limited because of the residual of fluorescent whitening agent (FWA). So the removal of FWAs from waste paper is an important task in the recycling process to improve the use of recycled resources. In this study, we focused on the FWAs used for surface treatments and carried out physical and chemical treatments to remove them from white waste papers. The white waste papers were disintegrated with a surfactant in different pH and temperature conditions, and then handsheets were made for the measurement of the fluorescence index, which is proportional to the amount of FWAs on papers. The effect of the flotation process on the removal of FWAs after disintegration was also investigated. The fluorescence index decreased as the disintegration time increased, but over a relatively long time, the fluorescence index increased again, which indicated the readsorption of the FWAs detached from the cellulosic fibers of the white waste papers. The lowest fluorescence index was shown when the waste papers were disintegrated with a 0.3% surfactant addition at pH 10 and at $45^{\circ}C$. However, the flotation treatment was not effective, because the flotation induced contact between the detached FWAs and the cellulosic fibers, and re-adsorption occurred.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.3
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• pp.15-34
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• 2004

Diverse benefits such as reduction of fresh water consumption and effluent discharge, efficient use of raw materials and energy savings can be obtained by papermaking system closure. Closure of papermaking processes, however, causes many problems including reduction of the efficiency of additives, decrease of retention and dewatering, felt plugging, poor Paper quality, generation of slime and odor, poor vacuum efficiency, etc, and it has been recognized that accumulation of Inorganic and organic substances in the process white water is the prime cause of these problems. Therefore, technological developments for preventing accumulation of these detrimental substances are urgently required for Implementing papermaking system closure. Understanding of the accumulation phenomena of the inorganic and organic substances in the papermaking process white water is prerequisite for papermaking system closure. In this study a process simulation method was used to analyze the accumulation phenomena of anionic starch In the process white water as the closure level of a fine paper making process is increased. A pilot paper machine was used as a model process. Starch adsorption and desorption models were developed based on the concept of starch adsorption ratio, which was not considered in previous studies. Steady state simulation studies were carried out based on this model using a commercial simulator. In steady state simulation, the variation of dissolved starch concentration in each process unit was monitored as a function of white water usage for wire shower. The result of the steady state simulation showed that dissolved starch concentration and its increase ratio in Process units increased as white water usage ratio for wire shower increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.9-15
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• 2004

Micro inorganic solids and dissolved materials contained in the white water of linerboard process was obtained by centrifugation, and their characteristics were analyzed along with their effects on the mechanical properties of linerboard. Micro inorganic materials had little influence on tensile index and ZDT of UKP sheets. They showed rather a positive effect on mechanical properties of KOCC sheets due to adsorbed polymer. Mechanical properties of KOCC sheets decreased remarkably when the concentration of dissolved materials increased especially above 4000 ppm.