• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.73-83
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• 2002

Gloss is very important optical property influencing the perceived quality of the paper surface as well as the surface after printing. Although the average gloss level of paper products or printed images is important to meet end use specifications, the occurrence of gloss mottle, or non-uniformity of gloss, is often of greater concern for meeting quality requirements, especially for the high gloss paper. Gloss variation originates from the irregularities of paper surface, especially surface roughness of paper. Roughness of paper can be divided into micro-roughness (under $1\mu m$ scale in variation) and macro-roughness (over $1\mu m$ scale in variation) depending on the scale of the irregularities. A clearer understanding of the gloss variation of paper can be achieved by separating the contributions of these two scales of roughness, and characterizing them independently. In order to do this, a novel gloss measuring method was introduced. This can detect local gloss with very high resolution. The effect of macro-roughness on gloss variation, which was identified by the measurable surface topography, was separated from the total gloss variation by using this method. The effect of micro-roughness was then estimated indirectly. The local gloss variations of various paper samples were then evaluated to demonstrate the utility of this approach.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.47-53
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• 2006

To meet the ever increasing quality demand of coated papers and duplex boards, the local gloss variation and print unevenness must be avoid. To do this, surface roughening phenomenon which affects local gloss and print unevenness was investigated. In this study, the effect of roughness and densification of sheet obtained at various calendering conditions on surface roughening was examined. To evaluate the calendering effect properly we introduced a new value of roughening index by moisture for evaluation of surface roughening. Caliper and roughness of sheet decreased with increasing of calendering temperature and pressure, and the remarkable reduction of those properties occurred at the temperature around Tg. Roughening index increased when the amount of water increased and calendaring temperature and pressure increased. And as the sheet became denser by calendering, the roughening index increased to some extent. But roughening index by moisture is the lowest for sheet precalendered at higher temperature condition. When the surface of calendered sheet is rougher, there is more roughening of surface. The severe condition of calendering made the roughening index by moisture small.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2005.11a
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• pp.45-53
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• 2005

A novel method for evaluating the anisotropy of the deterministic features in a stochastic 2D data is introduced. The ability of the wavelet transform for the identification of the abrupt discontinuities could be used to characterize the boundary of the deterministic area in a 2D stochastic data, such as flocs in paper structure. The one-dimensional wavelet transform with a small-scale range in MD and CD could quantify the amount of the edge in both directions, depending on the intensity of each floc. The flocs that are aligned in the MD direction result in a higher value of local wavelet energy in the CD direction. Therefore, the ratio of the total wavelet energy in CD and MD directions can be used as a new anisotropy index. This index is a measure of the floc-orientation and can provide an excellent tool to obtain the orientation distribution and the major oriented angle of flocs. Various simulated images and real stochastic data such as local gloss variation of printed image and formation image, have been tested and the results show this analysis method is very reliable to measure the anisotropy of the deterministic features.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.305-308
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• 2013

This study was conducted to describe the external morphology of Platypus-koryoensis Murayama in immature stage, to determine each instar based on larvae head-capsule, and to measure individual and local variations in the number of mycangia of adult. Egg of P. koryoensis, had oval shape and lengths of the major and minor axis were $0.67{\pm}0.051$ mm and $0.41{\pm}0.053$ mm, respectively. Body colour of $5^{th}$ instar was gloss white with well-developed mandible. Larvae of P. koryoensis grew up to $5^{th}$ instar and each instar was clearly classified by head capsule width. Head capsule width for $1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, and $5^{th}$ instar larvae were $0.35{\pm}0.004$ mm, $0.45{\pm}0.010$ mm, $0.67{\pm}0.039$ mm, $0.94{\pm}0.069$ mm and, $1.12{\pm}0.007$ mm, respectively. The colour of pupa was pale yellow and its length was $4.64{\pm}0.044$ mm. The number of mycangia per female had individual variations from 5 to 12 and 83% of the adults had from 6 to 8 mycangia. There was no significant difference in number of mycangia collected from between Namyangju region and Honchen region.