• Laser Solutions
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• v.3 no.1
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• pp.2-11
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• 2000

Laser cleaning has begun to attract a considerable amount of interest recently as a new cleaning technique among scientists and engineers. The unique characteristics of laser cleaning are currently finding successful applications in industry, in medicine as well as in the world of art conservation. This paper takes an overview of the laser cleaning technique itself including basic principles and characteristics, and provides an account of current trends especially with regard to practical applications. Experience with its successful applications in various fields shows that laser cleaning may be about to emerge as a real alternative to conventional cleaning methods.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.86-87
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• 2003

Unstructured grid system is suitable for flows of complex geometries. For problems with moving boundary walls, the grid system must be changed and deformed with time if we use a body fitted grid system. In this paper, a new moving-grid finite-volume method on unstructured grid system is proposed and developed for unsteady compressible flows with shock waves. To assure geometric conservation laws on moving grid system, a control volume on the space-time unified domain is adopted for estimating numerical flux. The method is described and applied for two-dimensional flows.

• Journal of Conservation Science
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• v.34 no.6
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• pp.517-524
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• 2018

This study using a method different from those employed previously, the anatomical characteristics of paper-mulberry wood were confirmed by observing three different sections. In addition, the factors affecting the pulp and papermaking processes were analyzed in terms of morphological properties such as the fiber length and width, lumen width, and chemical composition of the paper-mulberry bast fiber. The anatomical characteristics of the paper-mulberry wood were a ring porous or semi-ring porous structure with the vessels showing solitary pore and radial array. The medullary ray of the tangential section showed 1-3 rows and common helical thickening. Consequently, the paper-mulberry wood has the same anatomical characteristics throughout. The morphological characteristics of the paper-mulberry bast fiber are a fiber length of 6.58 to 9.01 mm, fiber width of 15.85 to $27.80{\mu}m$, lumen width of 4.50 to $12.54{\mu}m$. The D sample of Gangwon was the most suitable for the pulp and papermaking processes, in terms of its derived morphological ratios. Comparing the chemical compositions, the C sample of Gyeongsang had a high holocellulose content (90%). Thus, the findings herein will aid in determining the quality of Korean paper post production.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.785-808
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• 2016

The objective of this study was to investigate the effect of the short-term weathering on the flame retardant performance of wood coated with Dancheong. Flame retardants were applied on the Dancheong coated Korean red pine. Flame retardants applied panels were layed at the two conditions of outdoor exposure and artificial aging to assess the reliability of artificial aging. Flame retardants used were commercial products developed for historical wooden buildings. Scanning electron micrographs revealed the forming of carbonized membrane by melting of flame retardant on wood surface. These carbonized membranes may help delay the further combustion of wood. Flame retardant performance was assessed by measuring heat release rate (HRR) and total heat release (THR) by cone calorimetry. There was no difference in flame retardant performance between before and after 6-month outdoor exposure tests. And also no difference in flame retardant performance between before and after 2-week artificial aging which corresponds to 6-month outdoor exposure. Both tests showed the similar results of combustion characteristics.

• Journal of Conservation Science
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• v.26 no.1
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• pp.61-67
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• 2010

After selecting five types of adhesive epoxy resin for metallic cultural assets such as $Araldite^{(R)}$ rapid type, $Devcon^{(R)}$, $Araldite^{(R)}$ SV427+HV427, $CDK^{(R)}$520, $Araldite^{(R)}$ AW106+HV953 which had already been studied, this paper approached more closely the problem of yellowing and the signal of aging with time passing by connecting the problems with the safety of metallic cultural assets. The change of physical properties according to the change of state of epoxy adhesives was investigated through the change of flexural strength and the change of surface hardness by artificially providing the possible environmental change factors such as ultra-violet ray, and acid base, and how the epoxy chemically changes in its ingredients by the environment was analyzed through FT-IR. As a result of the experiment, for the most part of adhesives brought about the physical change of flexural strength, the change of surface hardness, and the chemical change of chemical ingredients as the product of alcohol, which were respectively different according to the time of ultraviolet irradiation, and acid base change. Under most of the conditions, SV427+HV427 and $CDK^{(R)}$520 were fairly stabilized under each condition of weatherability, but it seems that they should be refrained from being applied in case that the area to restore is thin and wide because the degree of flexural strength of themselves is low. Also, it is found that the preservation environment is very important not only for artifacts but also for the preservation of resins sused for preservation treatment.

• Journal of Conservation Science
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• v.26 no.1
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• pp.25-32
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• 2010

The yellowing is always occurred phenomena in epoxy restoration material of antic-ceramics. For re-restoration of remains with epoxy restoration material, the epoxy elimination step is the first one in all course of restoration In this paper, the chemically elimination treatments methods of epoxy in various antic-ceramics were discussed. We fabricated the epoxy elimination material for antic-ceramics restoration which were made up Dichloromethane and Dichlormethane based Dimethylformamide solution. Dichloromethane and Dichloromethane + Dimethylformamide mixture were applied to epoxy in various antic-ceramic sample. Particularly, Dichloromethane + Dimethylformamide solution had the best result in variation of color change, gloss, vending strength, weight, exfoliation time test after deposition in this solution. Dichloromrthane had the volume increase characteristics for epoxy material and Dimethylformamide had the mollification ones. So, Dichloromathane increased exfoliation in approximal surface of the epoxy material and antic ceramic, and Dimethylformamide decreased the surface hardness of epoxy. In this result, epoxy material even inside of ceramic that have very weak inside bonding is adaptable and stable eliminated. And in order to show the perfect elimination of this material, we successfully dissolve the epoxy restoration material in one antic pottery that is in one university museum's possession using this mixture. So, there is guarantee in the eternity and stabilization of restoration for antic-ceramics.

• Journal of Conservation Science
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• v.30 no.2
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• pp.123-136
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• 2014

Considering that decision in conservation treatment for damaged objects should consider not only various options of methodology of intervention but also possible consequences of different types of intervention, it is a difficult task to decide and propose clear and safest solution of preserving an object. In addition, it should be constantly challenged by conservators even if it is proved technique or methodology in a past treatment. Therefore, there is no absolute solution which can be applied to all practice but each decision can be different case by case. It is not possible to estimate the way how the present condition of material and environmental aspects would affect to the condition of an object in future. However if conservators keep trying to set out various ways of analysing pro and against effect of past treatments, it would be able to provide useful logics of proving efficiency and appropriateness of a certain treatment. Understanding that the advantage of laser technique is to adopt a way of cleaning an object without making a direct contact, which is different from other techniques, this paper aims at securing stability of laser techniques, although it remains a limitation in the compatibility to all other materials. This study has examined reacting process on the painted pigments against laser beam by using CLSM in order for it to display both the problems from such reacting process and the efficiency of it as a cleaning methodology. It has intended to estimate the result of laser techniques and propose the range of applicability.

• Conservation Science in Museum
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• v.8
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• pp.13-24
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• 2007

The Department of Fine Art requested the conservation science team to examine the technique of painting with gold powder on the gold painted porcelains, which were made in Korea and China, among the items possessed by National Museum of Korea in order to publish it in the research paper collection of the Exchange Exhibition of Korea and China Porcelains. Among the items possessed by National Museum of Korea, such items were included as, an item of Koryo inlaid celadon (No. Gaesung 106), called the celadon with inlaid work (Korean name: Cheongjasanggam suhawonmun geumchaepyunho), which was decorated in the layer of glaze using gold power, an items of tea cup called "Temmku da wan" (No. Bongwan 10011), which was manufactured in the time of Song dynasty of Chinese history, an items of gold cup called "Siyuchohwamun hwageumwan" (No. Bongwan 2027), and an items of a porcelain called "Siyuwan" (No. Duksoo 3322). As the result of the examination, the stabilizing method of baking the decorated porcelains is similar, after they are painted with the pigment mixed with fine gold powder and the glaze solvent, but the treatment method of the colors is a little different among them. In other words, there is a big difference between them, for example, in the case of Koryo celadon, because the gold coloring was painted carefully one by one on the splendid decorations of inlaid works, while in the case of Chinese porcelains, butterflies or arabesque designs are decorated on the layer of the glaze in the porcelains of no decoration, using the stencil skill. According to the result of this examination, the part of the porcelain, whose layer of gold color was peeled off, could be restored, and as the result of the restoration, it was confirmed how beautiful and splendid the gold porcelain had been at the time of being manufactured.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.86-95
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• 2018

The objective of this study was to describe the development and testing of an initial ecological health assessment model, based on the index of biological integrity (IBI) using fish assemblages, before establishing the final and currently used model for ecological health assessment, conservation and management of freshwater fish in Korea. The initial fish IBI model was developed during 2004~2006 and included 10 metrics, and in 2007 the final IBI 8-metric model was established for application to streams and rivers in four major Korean watersheds. In this paper, we describe how we developed fish sampling methods, determined metric attributes and categorized tolerance guilds and trophic guilds during the development of the multi-metric model. Two of the initial metrics were removed and the initial evaluation categories were reduced from six to four (excellent, good, fair, poor) before establishing the final national fish model. In the development phase, IBI values were compared with chemical parameters (BOD and COD as indicators of organic matter pollution) and physical habitat parameters to identify differences in IBI model values between chemical and physical habitat conditions. These processes undertaken during the development of the IBI model may be helpful in understanding the modifications made and contribute to creating efficient conservation and management strategies for stream environments to be used by limnologists and fish ecologists as well as stream/watershed managers.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.645-654
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• 2015

This paper attempts to quantitatively assess the conservation value of Ellobium chinense (EC), which belongs to the endangered marine species designated by Ministry of Oceans and Fisheries. To this end, we apply the contingent valuation (CV) method, an economic technique of valuing a non-market goods such as EC. A national survey of randomly selected 1,000 households was administered in order to derive the public's willingness to pay (WTP) for conserving EC. One-and-one-half-bound model was adopted to elicit the WTP responses and a spike model was employed to deal with the zero WTP responses. The results show that the conservation value of EC is estimated to be 2,346 won per household per year that is statistically significant at the 1% level. Expanding the value to the national population gives us an annual value of 43.8 billion won. We can judge that the Korean people are willing to pay a significant amount to conserve EC.