• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.3
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• pp.59-68
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• 2013

The cotton contains various impurities such as protein, wax, pectins, coloring matter, even though cotton has been a major source of pure cellulose. The purification processes have been commonly applied to obtain the pure cellulose. However the excessive purification treatments could lead to the damage in the cellulose structure which could result in the degradation of cellulose and the limited application of cotton cellulose. In this study, the changes in cellulose structural properties such as crystallinity and DP(degree of polymerization) by the various conditions of the purification processes were investigated. The less toxic agents such as hydrogen peroxide and sodium silicate were applied for the purification treatment in this study. The increase in the process times, the temperature and the applied amount of chemical agents resulted in the more purified cellulose. The DP of cotton cellulose was increased at the first weak conditions by the reduction of small molecules such as pectin, wax, and so on. Especially the 2 % addition amount of $H_2O_2$ with $Na_2SiO_3$ resulted in the higher value in the DP and the brightness compared to the 1.5 % addition amount of $H_2O_2$. However, the 4 % addition amount of $H_2O_2$ with $Na_2SiO_3$ showed the decreased value because of excessive treatment. In case of the changes in the crystallinity (Gjk), the highest value of the crystallinity was obtained by the 2% addition amount of $H_2O_2$ on the cotton cellulose, which showed similar with the change in the DP.

• Journal of the Korea Society of Computer and Information
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• v.28 no.5
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• pp.49-56
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• 2023

Currently, e-commerce is changing from a digital twin to a metaverse world. The metaverse world is an intermediate form between virtual and real worlds and is operated as a coin-based meta-commerce. In this meta-commerce world, blockchain-based NFT coins are used when trading items (contents). In this study, we studied how to issue a large number of NFT coins (certification) rather than issuing a single type of NFT. The research method was designed to produce content layer-based and automatically create the desired quantity using a mass NFT index and automatic generation method. In this study, a layer overlap method (background, body, etc.) was used with a Phyton-based program for mass minting. As a result, it can be used as a blockchain-based certificate that can prove a group of many people. In addition, the content created with the NFT index was registered on the NFT sales site to confirm its utilization and value.

• Journal of Conservation Science
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• v.16 s.16
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• pp.15-20
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• 2004

Two pieces of choson-Tongue(朝鮮通寶) minted at 1423 A.D. were analyzed by atomic absorption spectroscopy and neutron activation analysis. The measurement of lead isotope ratios was also carried out in order to predict the provenance of raw materials used for minting. The Chosen-Tongue was minted as bronze having the chemical compositions of $Cu\;90\%,\;Pb\;3\~4\%,\;Sn\;2\~3\%$, which were different from the typical composition of Chinese and Japanese coins. The results of lead isotope ratios showed that the provenance of raw materials used for minting had a possibility to be originated from South China. And application of statistical linear discriminant analysis (SLDA) to the provenance of lead used for minting of Chosen-Tongue was confirmed.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.04a
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• pp.199-200
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• 2007

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.652-657
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• 2013

In this study, we developed a counting method for non-contact ID cards using an optical fiber displacement sensor instead of the traditionally used friction counting method. The proposed method has the advantage of high speed and automated measurement. For counting non-contact ID cards, an H-type optical fiber sensor, jig part, and counting program are developed separately to build the system and adjust it. Through the experimental test results, it was confirmed that counting is possible with one type of international ID card and one type of financial security card based on ISO7810. Furthermore, by applying the proposed method to 100 ID cards 100 times repeatedly, it was confirmed that it has high accuracy and an error ratio of 0%. We experimentally demonstrated that the proposed counting method for non-contact ID cards using an optical fiber displacement sensor can perform measurements with high accuracy and high speed.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.67-73
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• 1993

This study was attempted to develop the Special Sheet Former for Hanji (Korean Traditional Paper), which could be easily used anyone who has no any special skill, and to evaluate its sheet forming characteristics. The sheet former for Hanji was designed, manufactured and tested its sheet forming features. This former was resulted in superior even basis weights and good formation of sheets without any special technological experiences, but poor consolidation according to the difficulty of web pressing during dewatering process. Sulfomethylated pulping resulted in the superior pulp with high yield and better quality compared to those of alkali and alkali-peroxide pulps. Since the pulp was so bright, there was almost no need additional bleaching.

• Journal of Conservation Science
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• v.17 s.17
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• pp.33-38
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• 2005

One piece of Haedong-Tongue(해동통보) minted at 1,102 A.D. was excavated from No.20 wooden coffin, Sinbong-dong, Cheongju. It was analyzed by micro-XRF and ICP and determined the concentrations of ten elements such as Cu, Pb, Sn, Zn, Fe, Mn, Sb, Co, As, Ag and Ni. The measurement of lead isotope ratios was also carried out in order to predict the provenance of raw materials used for minting of Haedong-Tongbo. It was found that Haedong-Tongbo was minted with three compositions of $Cu\;75.5\%,\;Pb\;13.3\%\;and\;Sn\;6.0\%$, which were different from the typical composition of Chosen-Tongbo and Sangpyung-Tongbo used in Chosen dynasty. Lead isotope ratios of Haedong-Tongbo showed that the provenance of lead used for minting of it suggested the possibility to be originated from Southern part of Korea.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.11a
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• pp.83-83
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• 2000

Alkylketene dimer was known as a cellulose reactive or alkaline size because it does not require to fix to the fiber as do the traditional rosin sizes. A proposed sizing mechanism of AKD was the formation of P -ketoester bond between AKD and cellulose which provides the permanent attachment and the orientation of the hydrophobic alkylchains outward. However, some questions about the reaction had arisen and thus, the sizing mechanism of AKD has been a subject of controversy for several decades. The major concern of the controversy is that AKD is really reactive with cellulose or not in the papermaking conditions. In this study, reaction between AKD and pulp fiber was investigated, in order to find out whether AKD forms P-ketoester with pulp fiber during aging under no catalyzed neutral condition with obvious spectroscopic evidence. In addition, effect of aging treatment on the sizing development was studied. It has been disclosed that, in absence of water, AKD reacted with cellulose to form P -ketoester linkage under no catalyzed neutral condition, while, in presence of water, most of AKD was hydrolyzed to a dialkyl ketone or P -ketoacid. In addition, during the aging treatment of AKD-sized paper, its typical IR spectra bands gradually were reduced, completely disappeared after 6hr aging, and formed new absorption bands at 1707cm-' and shoulder peak at 1700cm-' which refer to the typical dialkylketone absorption bands. Therefore, the formation of P -ketoester between AKD and pulp fiber is impossible in the practical papermaking process. It could be suggested that the sizing development of AKD-sized paper is obtained by next two mechanism: 1) formation of a thin-layer of AKD on the fiber surface through melting and spreading of AKD emulsion particles by heat and 2) the hydrolysis of AKD to dialkyl ketone which has higher melting point, during drying and storage of AKD sized papers.

• 보존과학연구
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• s.10
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• pp.1-40
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• 1989

Between 1976 and 1984 approximately 26.7 tons of Chinese coins were recovered from a shipwreck which was found at the seabed of the Shin an area in the south-western coast of the Korean peninsula. Elements, Cu, Pb, Sn, Fe, Sb, As, Zn, Ag, Ni, Co and Mn, of 54 pieces of the coins were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy(ICP-AIS). The result shows that Ch, Pb, and Sn were found to be major elements roughly the coins with the ratio of 7 : 2 : 1, respectively. Trace elements were classified into 3 levels according to the avarage concentration : Fe,As and Sb(0.1-0.5%), Ag, Mi, Co and Zn(100-1000ppm) and Mn(10ppm). Some systematic tendencies are observed in the composition change with a function of their minting ages .The Wuzhu coins(오수전) from the Eastern Han dynasty(A.D.25-219 )are much more abundant in Cu than the coins of Tang dynasty(A.D.618-907) and later periods. Major element compositions of the Kai -tong Vuan-Bao(개통원보) coins from the Tang dynasty, were remarkably variable. In general, however, the Tang dynasty coins were much more abundant in Cu than the Song dynasty(A.S.S60-1279) coins. The amount of major elements Cu and Sn decreases while that of Pb in creasesby passage of age from the Bei Song dynasty(A.D.960-1127) to later Nam Song dynasty (A.D.1127-1279 ). It means that the quality of coins mere degraded. The amounts of trace elemends(Fe, As, Co, Hn) increases with the above age. High amounts of trace elements are supposed to be a reflection of immaturity of minting techniques or use of impurity-rich raw materials. The Jin dynasty(A.D.1125-1234) coins are found to be rich in Sn and thus contain Pb as the third component. It is quite different from the coins of the Song dynasty. The Zhi-dai Tong-Bao(지대통보) coins of the Yuan dynasty from A.0.1310 are much more abundant in Cu and Sn than those of the Nam Song dynasty .

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.2
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• pp.149-156
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• 2011

In the recent years, power analysis attacks were widely investigated, and so various countermeasures have been proposed. In the case of block ciphers, masking methods that blind the intermediate values in the en/decryption computations are well-known among these countermeasures. But the cost of non-linear part is extremely high in the masking method of block cipher, and so the countermeasure for S-box must be efficiently constructed in the case of AES, ARIA and SEED. Existing countermeasures for S-box use the masked S-box table to require 256 bytes RAM corresponding to one S-box. But, the usage of the these countermeasures is not adequate in the lightweight security devices having the small size of RAM. In this paper, we propose the new countermeasure not using the masked S-box table to make up for this weak point. Also, the new countermeasure reduces time-complexity as well as the usage of RAM because this does not consume the time for generating masked S-box table.