• 펄프종이기술
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• 제47권4호
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• pp.127-135
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• 2015

Artists have been used animal glues for a long time as binding and sizing materials of paintings in many countries including Korea. Since animal glues as a binding material lose their own adhesive strength by aging, pigment particles or pigment layers are easily detached from painting surface. Restaurators prefer to use animal glues for consolidation of pigment particles or pigment layers because artists use animal glues as a binder for their painting works. It is widely known that animal glues have different characteristics such as viscosity, stability on water etc. But there are still a few requirements to consider their stabilities for the restoration of paintings. Therefore, this study was aimed to evaluate of stability and efficiency of animal glue applications. The efficiency of animal glue application was decreased with increasing the concentration of animal glue solution. This result means the simple tendency, but does not representative data for other animal glues made from same raw materials. In most cases, the surface and mechanical characteristics of animal glues are dependent on some factors, like viscosity and concentration of animal glue solution.

• 펄프종이기술
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• 제48권3호
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• pp.80-90
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• 2016

The purpose of this study was to investigate the functional properties of natural dyed Hanji for cultural properties conservation and storage. To estimate functional properties of Hanji, antimicrobial, insect repellent test, and Oddy test were executed. Hanji dyed with 10% Golden thread (Coptis chinensis), a natural dye and silver nitrate mordanting showed the most excellent antifungal activities against A. niger, P. chrysogenum, and Trichoderma sp. before and after aging. The insects repellent test followed didn't indicate significant effects on treated Hanji against Lasioderma serricorne, Sitophilus zeamais, and Tribolium castaneum. According to Oddy test result, Hanji dyed with Golden thread and silver nitrate caused no significant corrosions on copper, silver, and lead after aging 28 days.

• 펄프종이기술
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• 제38권4호
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• pp.1-9
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• 2006

Increasing the filler content of sheet provides an opportunity for saving production cost through fiber replacement with relatively low-priced filler. But increasing the filler content tends to decrease the strength of paper and filler retention. To overcome these problems, preflocculation technology of fillers has been suggested. To evaluate the effect cationic polymers on the size and size distribution of preflocculated GCC and their shear stability, cationic PAM and cationic starch were used. Results showed that cationic PAM formed large prefloc at low dosage. It was required to add 15 times as high as cationic starch to cationic PAM to obtain the same size prefloc. But preflocs formed with cationic starch was superior in shear stability to those formed with cationic PAM. With the increase of shear rate the size of preflocs decreased. Greater amount of small preflocs or un-flocculated fillers was observed when the dosage of polymers was low and this ended up low ash retention in handsheets.

• 펄프종이기술
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• 제37권4호통권112호
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• pp.1-7
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• 2005

This study was carried out to investigate the characteristics of extracellular cellulase and xylanase from Fusarium pallidoroseum and Aspergillus niger, such as enzyme activity and stability by various pH, temperature and metal ions, for application into enzymatic deinking system. The optimal temperature and pH for enzyme activity and stability of Fusarium pallidoroseum and Aspergillus niger were $50^{\circ}C$, pH 5.0 and $60^{\circ}C$, pH 9.0, respectively. Certain metal ions, calcium and cobalt, brought to elevate cellulase and xylanase activity from F. pallidoroseum and A. niger. With these results we suggest that enzymatic deinking system should be proceed at $50\~60^{\circ}C$ under their optimal pH condition.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 추계학술발표논문집
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• pp.93-102
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• 2007

Biocomposite was organized with biodegradable polymer and natural fiber that has potential to be used as replacement for glass fiber reinforced polymer composite with the benefits of low cost, low density, acceptable specific strength, biodegradability, etc. Until now, non-wood fibers have been used as reinforcements of biocomposite which are all plant-based fibers. The present study focused on investigating the fabrication and characterization of biocomposite reinforced with red algae fiber. The bleached red algae fiber(BRAF) showed very similar crystallinity to the cellulose. It has high stability against thermal degradation (maximum thermal decomposition temperature of 359.3$^{\circ}C$) and thermal expansion. Biocomposites reinforced with BRAF have been fabricated by a compression molding method and their mechanical and thermal properties have been studied. The storage modulus and the thermomechanical stability of PBS matrix are markedly improved with reinforcing the BRAF. These results support that the red algae fiber can be used as an excellent reinforcement of biocomposites as "green-composite" or "eco-composite".

• 펄프종이기술
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• 제40권2호
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• pp.43-56
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• 2008

The purpose of the experiment was to evaluate the material stability of the paper of the annals of Joseon Dynasty for the conservation purpose and the categories were as listed below : 1. Procuring traditional Hanji and semi-Hanji from different regional hanji paper mill. 2. Artificial accelerated aging treatment to examination its stability (UV irradiation, dry heat) 3. Analysis of optical, physical characteristic. The suitable Hanji for categories would be used as a reconstruction material for the waxel paper in the papers of the annals of Joseon Dynasty.

• 펄프종이기술
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• 제44권1호
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• pp.1-9
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• 2012

In this study, 5 solvent soluble polymers were treated on Hanji. Mechanical properties, morphology and oxidation index with thermal aging were measured on the aged Hanji, dewaxed Hanji and polymer treated Hanji. Synthetic polymers(such as polylactic acid, polybutylene succinate, polystyrene) treated Hanji had higher strength and thermal stability than cellulose derivatives(such as cellulose nitrate and cellulose acetate) treated Hanji. Polymer treated Hanji showed a little bit of color change. The oxidation index of PS treated Hanji did not increase with thermal aging because it did not have a carboxyl group in chemical structure. Finally, polystyrene was found to be the most efficient method for strengthening the dewaxed Hanji. The best aging safety and thermal stability were obtained at the polystyrene 3% solution.

• Ocean Systems Engineering
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• 제2권3호
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• pp.229-238
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• 2012

We discuss the bi - stability that is possibly exhibited by a liquid free surface in a parametrically - driven two-dimensional (2D) rectangular tank with finite liquid depth. Following the method of adaptive mode ordering, assuming two dominant modes and retaining polynomial nonlinearities up to third-order, a nonlinear finite-dimensional nonlinear modal system approximation is obtained. A "continuation method" of nonlinear dynamics is then used in order to elicit efficiently the instability boundary in parameters' space and to predict how steady surface elevation changes as the frequency and/or the amplitude of excitation are varied. Results are compared against those of the linear version of the system (that is a Mathieu-type model) and furthermore, against an intermediate model also derived with formal mode ordering, that is based on a second - order ordinary differential equation having nonlinearities due to products of elevation with elevation velocity or acceleration. The investigation verifies that, in parameters space, there must be a region, inside the quiescent region, where liquid surface instability is exhibited. There, behaviour depends on initial conditions and a wave form would be realised only if the free surface was substantially disturbed initially.

• 한국정밀공학회지
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• 제31권3호
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• pp.189-197
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• 2014

Diffractive optical elements (DOEs) - in general a complex pattern of micro- and nano-scale structures - can modulate and transform light in a predetermined way. Their importance is being increased nowadays because they can be designed to handle a number of simultaneous tasks. In view point of machining DOEs, it is a big challenge to fabricate micro- and nano-scale structures on a free-form surfaces. In this paper, the state-of-the-art of the ultra-precision machine tools is reviewed. Also some technical issues which determine the machine tool accuracy are discussed.

• 펄프종이기술
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• 제40권1호
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• pp.62-67
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• 2008

Biocomposite was fabricated with biodegradable polymer and natural fiber that has potential to be used as replacement for glass fiber reinforced polymer composite with the benefits of low cost, low density, acceptable specific strength, biodegradability, etc. Until now, mostly natural cellulosic fibers on land have been used as reinforcement for biocomposite. The present study focused on investigating the fabrication and the characterization of biocomposite reinforced with red algae fibers from the sea. The bleached red algae fiber (BRAF) showed very similar crystallinity to the wood cellulose. It has high stability against thermal degradation (maximum thermal decomposition temperature of 359.3$^{\circ}C$) and thermal expansion. Biocomposites reinforced with BRAF have been fabricated by a compression molding method and their mechanical and thermal properties have been studied. The storage modulus and the thermomechanical stability of PBS (polybuthylenesuccinate) matrix are markedly improved by reinforcing with the BRAF. These results indicate that red algae fiber can be used as an excellent reinforcement of biocomposites, which are sometimes called as "green-composites" or "eco-composites".