• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.191-197
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• 2014

Purpose : This study presents the usefulness assessment of metal artifact reduction for orthopedic implants(O-MAR) to decrease metal artifacts from materials with high density when acquired CT images. Materials and Methods : By CT simulator, original CT images were acquired from Gammex and Rando phantom and those phantoms inserted with high density materials were scanned for other CT images with metal artifacts and then O-MAR was applied to those images, respectively. To evaluate CT images using Gammex phantom, 5 regions of interest(ROIs) were placed at 5 organs and 3 ROIs were set up at points affected by artifacts. The averages of standard deviation(SD) and CT numbers were compared with a plan using original image. For assessment of variations in dose of tissue around materials with high density, the volume of a cylindrical shape was designed at 3 places in images acquired from Rando phantom by Eclipse. With 6 MV, 7-fields, $15{\time}15cm2$ and 100 cGy per fraction, treatment planning was created and the mean dose were compared with a plan using original image. Results : In the test with the Gammex phantom, CT numbers had a few difference at established points and especially 3 points affected by artifacts had most of the same figures. In the case of O-MAR image, the more reduction in SD appeared at all of 8 points than non O-MAR image. In the test using the Rando Phantom, the variations in dose of tissue around high density materials had a few difference between original CT image and CT image with O-MAR. Conclusion : The CT images using O-MAR were acquired clearly at the boundary of tissue around high density materials and applying O-MAR was useful for correcting CT numbers.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.2
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• pp.9-17
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• 2017

Purpose: The tissue description and electron density indicated by the Computed Tomography(CT) number (also known as Hounsfield Unit) in radiotherapy are important in ensuring the accuracy of CT-based computerized radiotherapy planning. The internal metal implants, however, not only reduce the accuracy of CT number but also introduce uncertainty into tissue description, leading to development of many clinical algorithms for reducing metal artifacts. The purpose of this study was, therefore, to investigate the accuracy and the clinical applicability by analyzing date from SMART MAR (GE) used in our institution. Methode: and material: For assessment of images, the original images were obtained after forming ROIs with identical volumes by using CIRS ED phantom and inserting rods of six tissues and then non-SMART MAR and SMART MAR images were obtained and compared in terms of CT number and SD value. For determination of the difference in dose by the changes in CT number due to metal artifacts, the original images were obtained by forming PTV at two sites of CIRS ED phantom CT images with Computerized Treatment Planning (CTP system), the identical treatment plans were established for non-SMART MAR and SMART MAR images by obtaining unilateral and bilateral titanium insertion images, and mean doses, Homogeneity Index(HI), and Conformity Index(CI) for both PTVs were compared. The absorbed doses at both sites were measured by calculating the dose conversion constant (cCy/nC) from ylinder acrylic phantom, 0.125cc ionchamber, and electrometer and obtaining non-SMART MAR and SMART MAR images from images resulting from insertions of unilateral and bilateral titanium rods, and compared with point doses from CTP. Result: The results of image assessment showed that the CT number of SMART MAR images compared to those of non-SMART MAR images were more close to those of original images, and the SD decreased more in SMART compared to non-SMART ones. The results of dose determinations showed that the mean doses, HI and CI of non-SMART MAR images compared to those of SMART MAR images were more close to those of original images, however the differences did not reach statistical significance. The results of absorbed dose measurement showed that the difference between actual absorbed dose and point dose on CTP in absorbed dose were 2.69 and 3.63 % in non-SMRT MAR images, however decreased to 0.56 and 0.68 %, respectively in SMART MAR images. Conclusion: The application of SMART MAR in CT images from patients with metal implants improved quality of images, being demonstrated by improvement in accuracy of CT number and decrease in SD, therefore it is considered that this method is useful in dose calculation and forming contour between tumor and normal tissues.

• The Journal of the Petrological Society of Korea
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• v.12 no.4
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• pp.196-206
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• 2003

The geochemical and mineralogical investigation on the rocks and repair material comprising of the Sungryemun (The 1st National Treasure) has been made. Rock of the Sungryemun is highly weathered coarse-grained calc-alkali granite. The rock consists mainly of quartz, perthite, plagioclase and biotite with small amounts of orthoclase, muscovite, chlorite and sericite, which are major weathering products from perthite. For obtaining informations about degree of weathering, mineral composition of the original rock calculated by CIPW norm and weathered rock composition determined by XRD quantitative analysis were plotted on a ternary diagram of quartz-potash feldspar-plagioclase. Original rock compositions are plotted on the central granite area. whereas weathered ones are plotted on the granite area close to quartz. The result means that quartz is more abundant in weathered rock, due to selective chemical weathering of potash feldspar and plagioclase over quartz. On the whole, surface of the rocks were black-coated, exfoliated and highly fractured due to the physical and chemical weathering and heavy load has made the cracks in the lower parts of the stone construction. Also, cement and nails, which was used as repair material, during the repair work in the early 1960's, has accelerated the weathering process. Furthermore, weathered conditions of repair materials are very severe. Therefore, it is very urgent to establish of the conservation plan for the Sungryemun.

• Journal of the Korean Institute of Gas
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• v.22 no.1
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• pp.64-77
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• 2018

This paper presents the prediction of the original gas in place(OGIP) by using the material balance method and decline curve analysis method with production history and pressure transient test data for four coalbed methane wells in the Horseshoe Canyon field. In this study, the conventional gas equation and the Jensen and Smith(J&S) equation were used to material balance analysis, and the Arps' empirical correlation and Khaled method were applied to decline curve analysis. From the results, the OGIP estimated from the conventional gas and the J&S method was small in difference as under 12%. Also, in case of decline curve analysis, it was found that the Khaled method has appropriated to calculate the OGIP, because the OGIP was estimated as unlimited value by the Arps' equation from the decline exponent of 1 - 3.5. The OGIP difference between conventional gas method and Khaled method was calculated as 8.67% ~ 31.04%, and those between J&S method and Khaled method was 13.67% ~ 26.49%.

• Korean Journal of Heritage: History & Science
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• v.48 no.2
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• pp.48-63
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• 2015

This study began with the purpose of awakening an interest in Korean Nu-jung and seeking application plan based on Nu-jung of Aneuisamdong. Also it intends to suggest activation plan of Nu-jung while using the culture of taste for the arts and classical scholar of ancestors with the physical place named Nu-jung as the medium. As concrete ways to activate Nu-jung, we suggested plans which use the game of go(Baduk), main material of the culture of taste for the arts and classical scholar, and increase availability by planning a program adding picturesqueness of Nu-jung. By bringing the material named the game of go(Baduk) to the place named Nu-jung, we suggested the plan capable of experiencing the culture of taste for the arts and classical scholar and also expecting local promotion and economical effect. And the plan is to design and conduct night program, 1 night 2 days program, tailored program, and so on by combining the material of the culture of taste for the arts and classical scholar with the medium named 'Dal(the moon)' in the static place named Nu-jung. The plans above are applicable to most of Nu-jung scattered all over the country, which means that we have a lot of Nu-jung in Korea and, at the same time, we have abundant contents to be used as cultural properties. Now it's important how to develop and use these contents through the connection with various academic fields in terms of managing cultural properties. By understanding the value of the original form of culture while emerging from simply using cultural properties, we can use cultural properties in a higher level. For this, preserving cultural properties should be supported by continuous interdisciplinary study.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.127-133
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• 2012

This paper is an experimental study on the freezing protection valve used for solar water heating, air-conditioning systems, and plumbing systems. When the phase change occurs from liquid to solid, most of the substances except water volumetrically shrink. And referred to as PCM(Phase Change Material) a substance with such properties, the phase change temperature varies depending on the material. To prevent the freezing of the plumbing system, such as air-conditioning system in the winter season, we developed a several types of freezing protection valve using PCM whose freezing temperature are $2-4^{\circ}C$. The working principle of the freezing protection valve is that the fluid inside the pipe is released to prevent the system-collapse when fluid temperature reaches the freezing temperature of the PCM. And then the valve is closed and returned to the original position automatically when the temperature of the operating fluid rises. In this paper, the operating temperatures, discharge flow rate and the response characteristics of the valve during the operation are tested and investigated. From the results of this research the freezing protection valves employing PCM are expected to be commercialized in the near future.

• Journal of Periodontal and Implant Science
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• v.41 no.2
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• pp.98-104
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• 2011

Purpose: The aim of this study was to evaluate 3.5 years-cumulative survival rate of implants placed on augmentedsinus using Osteon, a bone graft material, and to assess the height of the grafted material through radiographic evaluation. Methods: Twenty patients were treated with maxillary sinus augmentation and 45 implant fixtures were installed simultaneously or after 6 months healing period. The height of the augmented sinus and the loss of marginal bone were measured by panoramic and intraoral radiographs immediately after augmentation and up to 42 months (mean, 19.4 months) subsequently. Changes in the height of the sinus graft material were calculated radiographically. Results: The cumulative survival rate was 95.56% in all 45 implants. Additionall, normal healing process without any complication was observed in all patients. The original sinus height was mean 4.3 mm and the augmented sinus height was mean 13.4 mm after the surgery. The mean marginal bone loss till 42 months was $0.52{\pm}0.56\;mm$. The reduced height of Osteon was $0.83{\pm}0.38\;mm$ and it did not show significant correlation with the follow up periods (P=0.102). There were no statistically significant differences in reduced height of Osteon according to the simultaneous/delayed implantation (P=0.299) and particle size of Osteon (P=0.644). Conclusions: It can be suggested that Osteon may have predictable result when it was used as a grafting material for sinus floor augmentation.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.165-173
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• 2020

ABS and PLA are applied for restoring missing part of damaged ceramics, but are not similar to the material of ceramics, so this study conducted a research on the properties and applicability of ceramic resin. This study conducted actual restoration of ABS and ceramic resin as well as cast restoration method with experiment of properties. Results show that manufacturing of restored part showed higher precision than existing materials, which enables printing of tiny shapes showing excellent surface texture and gloss than L30 and ABS resin. As a result of measuring properties, the material showed excellent durability than existing materials with no contraction and deformation and compressive strength, but value of specific gravity and hardness can lower processability after manufacturing. Long-term monitoring, evaluation of reliability of ceramic resin applied in this study, additional researches on the restorability of the original shape when printing too thin or long restored part are needed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5545-5550
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• 2014

Background: Human biological materials from cancer patients are linked directly with public health issues in medical science research as foundational resources so securing "human biological material" is truly important in bio-industry. However, because South Korea's national R and D project lacks a proper managing system for establishing a national standard for the outputs of certain processes, high-value added human biological material produced by the national R and D project could be lost or neglected. As a result, it is necessary to develop a managing process, which can be started by establishing operating guidelines to handle the output of human biological materials. Materials and Methods: The current law and regulations related to submitting research outcome resources was reviewed, and the process of data 'acquisition' and data 'distribution' from the point of view of big data and health 2.0 was examined in order to arrive at a method for switching paradigms to better utilize human biological materials. Results: For the deposit of biological research resources, the original process was modified and a standard process with relative forms was developed. With deposit forms, research information, researchers, and deposit type are submitted. The checklist's 26 items are provided for publishing. This is a checklist of items that should be addressed in deposit reports. Lastly, XML-based deposit procedure forms were designed and developed to collect data in a structured form, to help researchers distribute their data in an electronic way. Conclusions: Through guidelines included with the plan for profit sharing between depositor and user it is possible to manage the material effectively and safely, so high-quality human biological material can be supplied and utilized by researchers from universities, industry and institutes. Furthermore, this will improve national competitiveness by leading to development in the national bio-science industry.

• Journal of the Korean Society for Library and Information Science
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• v.25
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• pp.265-294
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• 1993

At the present. one of the very important functions of the information center or library is to provide information service on time and to the right person. But it is impossible if the shape of the material is not complete. So it is important to keep the material of information complete. This study is on deacidification of paper materials for enhancing useful life of information. This study can be summerized as follews; The material needs deacidification is all of machine-made paper except neutral paper, and hand made paper which are below pH 6.5. The best way for the deacidification for the small amount of materals is to use aqueous deacidifiers such as Calcium Carbonate, Magnesuim Carbonate and Borax. For mass deacidification process, Methoxy Magnesuim Methyle Carbonate and Magnesuim Oxide, called