• Analytical Science and Technology
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• v.24 no.4
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• pp.256-265
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• 2011

Ambers have been used as a gemstone and a religious object since the ancient times and found in several archaeological sites in Korea. To prepare an enhanced conservation measures, we surveyed the chemical and spectroscopic properties of the ambers according to the provenance. Total 14 amber samples were collected from 6 different provenances including Baltic, Chiapas, Colombian, Dominican, Fushun and Madagascar amber. Infrared (IR) spectroscopic analysis was conducted for the non-destructive examination of the amber samples. They were also analyzed with pyrolysis/GC/MS (py/GC/MS) at the pyrolysis temperature of $300^{\circ}C$ with the on-line derivatization to trimethylsilyl ester. Baltic shoulder corresponding to the absorption at $1250cm^{-1}{\sim}1150cm^{-1}$ appeared in the IR spectrum of Baltic amber. IR spectra of the other ambers also showed somewhat distinctive characteristic peaks. In py/GC/MS analysis peaks assignable to succinic acid, dehydroabietic acid and pimaric acid were detected, which are known to be the components of the amber. In the meanwhile, the presence of compounds appearing in certain amber will be applied to differentiate the provenances of amber relics if their fragments are available for the analysis. These results are expected to help the confirmation of archaeological amber relics and archaeometric interpretation of provenances and manufacturing techniques.

• Journal of Conservation Science
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• v.30 no.4
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• pp.427-438
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• 2014

To measure the depth and extension on the surface cracks of the stone monument, ultrasonic pulse velocity targeted at the Mulgyeseowon Stele in Changnyeong was used in this research. Additionally, to establish a long-term countermeasure of management and conservation for this stele, we have investigated the material properties and damage on it and have conducted a precise diagnosis by a variety of non-destructive techniques. Our research has revealed that stones of the stele are composed mainly of three rock types according to the parts of it, alkali-feldspar granite, gabbro and diorite. The result of the deterioration evaluation has occurred that cracks, which are observed from every direction in the body of the stele, are the significant factors to reduce structural stability. The ultrasonic velocity for an evaluation on the properties of the stele has revealed that the speed was high in the order of body, pedestal and crown. Furthermore, to understand the present condition and occurrences of the cracks which have measured in many different forms on the stele quantitatively, we have estimated from 0.6 to 24.1cm deep of the cracks by To-Tc method using ultrasonic velocity.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.389-395
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• 2006

For the assessment of exsiting concrete structures, it is important to get the real strength of concrete. The load test or core test has many problems due to cost time, easiness, structural damage, and reliability and so on. Thus, various non-destructive test and statistical analysis techniques for strength assessment have been developed. As a result the real strength of concrete can be obtained by both direct and indirect test. In this study, a series of experimental tests of core strength and Schmidt hammer tests on 3, 7, 14, 28, 90, 180, 365, and 730 days' were done for predicting the compressive strength of high strength concrete with 65.0MPa of 28-days' strength. Each experimental results was analyzed by simple regression analysis. Then, reliability level and error rate between the proposed equations and the existing ones was examined. However, the application of the exsisting equations was inadequate to high strength concrete, because they were conducted under normal strength concrete. Therefore, the following compressive strength equations were proposed for predicting the compressive strength of high strength concrete by Schmidt hammer test. The proposed equations by Schmidt hammer test are as follows.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.496-502
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• 2017

The purpose of this study is to investigate the applicability of surface-wave techniques for the evaluation of the crack-repairing performance of an epoxy injection method in concrete. In this study, box-shaped concrete specimens with four different crack depths were made with identical mix proportions. The specimens with different crack depths were completely repaired using the same epoxy injection method. The spectral energy transmission ratio of surface waves is used as an index to differentiate the effects of crack depth and crack-repairing performance. The decrease of spectral energy transmission ratio in accordance with the increase of crack depth was identified before repairing. Furthermore, the spectral energy transmission ratio increased after the crack-repairing process in all specimens. The spectral energy transmission ratio is considered as a great indicator for estimating the crack-repairing performance of the epoxy injection method; the ratio was recovered up to almost 95% of the uncracked condition.

• Journal of Korean Traditional Oncology
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• v.16 no.1
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• pp.41-53
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• 2011

Background and Objectives: Iodine is an essential constituent of the thyroid hormones associated with the growth and development of humans and animals as an inorganic nutrition. This element may be accumulated in human blood, tissues and body through the intake of foodstuffs, a beverage, a nutritional supplement and a medicine, among others. The aim of the research is to find out a better medicinal stuff for the thyroid cancer patient who required a low level of iodine diet. Methods: Neutron activation analysis (NAA) used for the iodine analysis is one of nuclear analytical techniques using radiation and radioisotopes and very useful as sensitive analytical technique for performing both qualitative and quantitative multi-elemental non-destructive analysis of major, minor and trace components in variety of environmental and biological materials. In this study, iodine contents in ten kinds of oriental herb medicinal products, which is frequently used to cancer patients are determined by using instrumental neutron activation analysis (INAA) at the HANARO research reactor. The samples prescribed are manufactured as powdered form for taking medicine easily. The analytical quality control is performed to assure an uncertainty of the measurement and to compensate the measured data using a biological certified reference material, NIST SRM 1572, Citrus Leaves. The measured value is $1.89{\pm}0.35mg/kg$, and the relative error is 2.88%, and relative standard deviation is 19 % due to high counting error by small counts of gamma ray spectrum. The standard deviations for other elements such as Cl, K, Mn and Na were in the range of 2 to 8%. Result: The level of iodine contents of Biki-huan, Chungryong-huan and Chungcho-huan, samples detected is less than 6 mg/kg except Hangam Plus sample (more than 210 mg/kg) and six samples were not detected. Iodine in the samples of Shoxiho-tang, Shopunghualhyl-tang, Shocungryong-tang, Banhasaxim-tang, Insampaedox-san and Myunyuk Plus were not measured, but possible level of content can be estimated from the detection limits. In addition, the concentrations of some major elements like Cl, K, Mn, Na, in the samples were determined with the detection limits. Conclusions: Most of samples showed low iodine contents of less than 6 mg/kg but it turned out that most of testing samples can be used to classify the level of iodine diet samples considering the recommended low level of iodine diet 50 ${\mu}g$/day, and a better medicinal stuff for the thyroid cancer patient can be found.

• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.25-48
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• 2004

Structures show the phehomena of deformation and lowering of function with time-lapse by artificial environments and changes of geotechnical conditions or accumulation of initial deformation elements. This study aims the structural assessment of cultural property, Chum-Sung-Dae, located in Kyeongju city, Korea. It was built about 1,300 years ago, and has undergone deformation and ground-subsidence with time-lapse. Non-destructive evaluation techniques were applied to the Chum-Sung-Dae, to protect it from survey Because of this reason, 3D precise laser scanning surveying system was applied to measure the exact size of Chum-Sung-Dae, displacement and declining angles. Geophysical exploration also was applied to study the subsurface distribution of geotechnical parameters or physical properties. Natural frequencies were measured from real and model of Chum-Sung-Dae to study the dynamic characteristics of vibration and/or earthquake load and stiffness of structures.

• Archives of Plastic Surgery
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• v.35 no.4
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• pp.385-392
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• 2008

Purpose: The most effective methods of harvesting, preparing, and injecting autologous fat grafts have been inconsistent and conflicting. With its limitation as resorption in fat grafting, handling various techniques affect adipocyte survival, and is crucial to optimizing its long-term survival. To improve graft survival, re-implantation of cryopreserved adipocytes was developed. In addition, adipocytes do not induce immune rejection in response to non-self lymphocytes in a mixed lymphocyte reaction. The purpose of this study is to analyze the changes in cryopreserved adipocytes so as to determine the most efficient long-term storage period, and to analyze the changes in cryopreserved allografted adipocytes so as to determine the efficacy of cryopreserved adipocytes allografting. Methods: Fat tissues were harvested from the inguinal and retroperitoneal fat pad of mice. After the centrifugation of the harvested fat tissues, they were disintegrated with collagenase. The adipocytes were obtained by centrifugation of the disintegrated fat tissues. The adipocytes were treated as follows: (1) They were examined for weight and then frozen at $-20^{\circ}C$(n=25). For four months, each five frozen samples were taken and examined for weight and histologic changes in the 1st week, the 1st month, the 2nd month, the 3rd month, and the 4th month, respectively. (2) The adipocytes were immediately frozen at $-20^{\circ}C$(n=125). For four months, five frozen samples were taken, and allografted in the same time period as above. Finally, for four months, five cryopreserved allografted adipocytes were taken and examined for histologic changes in the same time period as above. Results: (1) Significant weight changes and histologic findings with inflammatory and destructive changes were observed in the cryopreserved adipocytes in three months. (2) Significant fat necrotic changes in the histologic changes with Hematoxylin and eosin stain were observed in the cryopreserved allografted adipocytes since the first week, independent of the freezing period. Conclusion: The study results show that the adipocytes that were cryopreserved for more than three months underwent obvious weight reductions and necrotic changes, and the adipocytes that were allografted without freezing were viable for four months, but the cryopreserved allografted adipocytes had obvious necrotic changes since the first week regardless of the freezing period.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.4-17
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• 2011

The Baekje's cotton fabrics were excavated from 'Neungsan-ri temple site in Buyeo' (September 1999-April 2000) and stored at Buyeo National Museum after conservation treatment. In this study, it carred out non-destructive, chemical and morphological analysis for fiber identification, also considered on influx, features and difference between the 'Baek-cheop-po(Three kingdom period's cotton fiber)' and 'Mok-myeon(imported by Munikjeom, late Korea dynasty)'. As a result, the fiber proved cellulose fiber through analytical researches like color reaction, FT-IR(chemical analysis). It was also confirmed lumens, typical dimensional structure(morphological analysis) as an features of cotton fiber. The fiber was the first evidence in ancient Korea's cotton. But it can not prove that whether weaving were made in Baekje's area. However there were documentation that people in Beakje make cloth to silk fabric from 'Mahan period'. We can suppose that they have had an old weaving techniques. This study has a great historical, academic values as the only evidence for the hypothesis of a weaving technique of the Baekje's cotton. Through comparison to each region's ancient cottons, we can investigate the species of Baekje's cotton and ancient Korea cotton's influx.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.737-746
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• 2008

Recently, NDTs (Non-Destructive Techniques) using electromagnetic(EM) properties are applied to the performance evaluation for RC (Reinforced Concrete) structures. Since nonmetallic materials which are cement-based system have their unique dielectric constant and conductivity, they can be characterized and changed with different mixture conditions like W/C (water to cement) ratios and unit cement weight. In a room condition, cement mortar is generally dry so that porosity plays a major role in EM properties, which is determined at early-aged stage and also be affected by curing condition. In this paper, EM properties (dielectric constant and conductivity) in cement mortar specimens with 4 different W/C ratios are measured in the wide region of 0.2 GHz~20 GHz. Each specimen has different submerged curing period from 0 to 28 days and then EM measurement is performed after 4 weeks. Furthermore, porosity at the age of 28 days is measured through MIP (Mercury Intrusion Porosimeter) and saturation is also measured through amount of water loss in room condition. In order to evaluate the porosity from the initial curing stage, numerical analysis based on the modeling for the behavior in early-aged concrete is performed and the calculated results of porosity and measured EM properties are analyzed. For the convenient comparison with influencing parameters like W/C ratios and curing period, EM properties from 5 GHz to 15 GHz are averaged as one value. For 4 weeks, the averaged dielectric constant and conductivity in cement mortar are linearly decrease with higher W/C ratios and they increase in proportion to the square root of curing period regardless of W/C ratios.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.287-293
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• 2010

Purpose: This study evaluated the effect of polishing techniques on surface roughness of polymethyl methacrylate (PMMA), as well as the influence of light-cured surface glaze and subsequent brushing on surface roughness. Materials and methods: A total of 60 PMMA specimens ($10{\times}10{\times}5\;mm$) were made and then divided into 6 groups of 10 each according to the polymerization methods (under pressure or atmosphere) and the surface polishing methods (mechanical or chemical polishing) including 2 control groups. The mechanical polishing was performed with the carbide denture bur, rubber points and then pumice and lathe wheel. The chemical polishing was performed by applying a light-cured surface glaze ($Plaquit^{(R)}$; Dreve-Dentamid GmbH). Accura $2000^{(R)}$, a non-contact, non-destructive, optical 3-dimensional surface analysis system, was used to measure the surface roughness (Ra) and 3-dimensional images were acquired. The surface roughness was again measured after ultrasonic tooth brushing in order to evaluate the influence of brushing on the surface roughness. The statistical analysis was performed with Mann-Whitney test and t-test using a 95% level of confidence. Results: The chemically polished group showed a statistically lower mean surface roughness in comparison to the mechanically polished group (P = .0045) and the specimens polymerized under the atmospheric pressure presented a more significant difference (P = .0138). After brushing, all of the groups, except the mechanically polished group, presented rougher surfaces and showed no statistically significant differences between groups. Conclusion: Although the surface roughness increased after brushing, the chemical polishing technique presented an improved surface condition in comparison to the mechanical polishing technique.