• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.582-585
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• 2015

In the aging society, TKRA is steadily increased because of joint diseases. Artificial joint used in TKRA generates metal artifacts in the MRI. Metal artifact may affect diagnosis. In study, We are going to minimize the effect of metal artifact to improve the value of diagnosis by changing the sequence and the type of artificial joint(Co-Cr, Ni-Ti). 1.5T AVANTO, plastic containers and each of the artificial joint (Normal, Co-Cr, NiTi) were used. After the artificial joints fixed in a paper cup was inserted in a plastic container of cylindrical, Signal intensity was measured. To obtain strong and uniform signal intensity, the plastic container was filled with water. We changed Sequences(T1 TSE, T2 TSE, PD TSE) and obtained an Axial image. After excepting the maximum and minimum values, We calculated the average of SNR, CNR and PSNR. Consequently, The SNR, CNR value of PD TSE are measured higher than these of T1 TSE, T2 TSE and The PSNR of Co-Cr is higher than this of Ni-Ti. The SNR of Co-Cr is similar to the SNR of normal comparing this of Ni-Ti. As a result, Using sequence of PD Tse and Co-Cr alloy is considered to be useful.

• Journal of Conservation Science
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• v.34 no.5
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• pp.379-385
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• 2018

This study examined the condition of degraded plastic artifacts and conducted materials assessments for conservation treatment. The properties and bond characteristics of five types of adhesives(EVA, PVAc, Cyanoacrylate) were evaluated to select the adhesive most suitable for conservation treatment. The degradation of plastic artifacts caused cracks, peelings, and surface warping. According to the FT-IR analysis, the synthetic resin used in the artifact was estimated to EVA type. The properties of the adhesives were evaluated through acidity, and hardness measurements. The results showed that acidity varies with the type of adhesive, and that the hardness of PVAc was higher than those of EVA. On comparing the bond characteristics of the samples after artificial degradation, it was found that PVAc and Cyanoacrylate increased the chromaticity and hardness of the samples, while EVA was the most stable with relatively little change. Thus, EVA was confirmed to be the most suitable materials for conservation treatment of degraded plastic artifacts. In this study, as the experiment of treatment materials based on actual artifact, it is expected that it could be used a basis research for conservation treatment of plastic artifacts.

• Analytical Science and Technology
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• v.27 no.2
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• pp.100-107
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• 2014

Plastic has been widely used in modern artworks' materials due to its merits of process ability and mass production. In the country, value of plastic artifact is increasing but the field of plastic study is limited to industrial purpose. In this study, Identification methods of plastic were performed by SPME-GC/MS and pyrolysis-GC/MS using trace of samples. As a result of identification using SPME-GC/MS, aromatic compounds were identified from polyvinyl chloride. And alkane compounds were identified from polyethylene, and polypropylene. Aromatic compounds were identified from polystyrene, and diethylene glycol appeared in polyurethane based on polyester was identified from polyurethane. As a result of identification using pyrolysis- GC/MS, aliphatic alkenes compounds and phthalate(DEHP) were identified from polyvinyl chloride. Aliphatic alkenes compounds and phthalate(DIBP) were detected from polyethylene. 1-hexene, etc., were detected from polypropylene, aromatic compounds were identified from polystyrene, and methylene diphenyl diisocyanate which is polyurethane basic material was confirmed from polyurethane. This study suggested that non-destructive SPME and pyrolysis-GC/MS are useful to identify compounds particularly polystyrene and polyurethane. These two analytical methods were expected to be applied for identification of unidentified plastic artworks before conservation treatment.

• Journal of Conservation Science
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• v.29 no.2
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• pp.127-138
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• 2013

Plastic, widely used as a material for contemporary art, get damaged as directly exposed to temperature, humidity, ultra violet, etc. And it is very quickly damaged in early time, once damaged, it can't recover into original state. But like this characteristics, there is a few advanced research in Korea. So this study deal with a rising value of plastic artifacts in other country, United Kingdom and France, current conservation state, identification and cleaning method. Also 5 types of cleaners(distilled water, ethanol, acetone, eraser) and adhesives(cyanoacrylate, epoxy, acrylic, chloroprene rubber) were evaluated by produced plastics(PVC, PE, PP, PS, PU). As a result of experiment, ethanol and acetone that were previous evaluated in other research performed in other country are the best cleaner. Result of degradation after adhesive, cyanoacrylate and epoxy resin showed better performance and stability. As a basic research, this study is expected that can be used in future researches.

• Structural Engineering and Mechanics
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• v.75 no.3
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• pp.369-376
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• 2020

The life of conventional steel plastic injection molds is long but manufacturing cost and time are prohibitive for using these molds for producing prototypes of products in limited numbers. Commonly used 3D printers and rapid prototyping methods are capable of directly converting the digital models of three-dimensional solid objects into solid physical parts. Depending on the 3D printer, the final product can be made from different material, such as polymer or metal. Rapid prototyping of parts with the polymeric material is typically cheaper, faster and convenient. However, the life of a polymer mold can be less than a hundred parts. Failure of a polymeric mold during the injection molding process can result in serious safety issues considering very large forces and temperatures are involved. In this study, the feasibility of the inspection of 3D printed molds with the surface response to excitation (SuRE) method was investigated. The SuRE method was originally developed for structural health monitoring and load monitoring in thin-walled plate-like structures. In this study, first, the SuRE method was used to evaluate if the variation of the strain could be monitored when loads were applied to the center of the 3D printed molds. After the successful results were obtained, the SuRE method was used to monitor the artifact (artificial damage) created at the 3D printed mold. The results showed that the SuRE method is a cost effective and robust approach for monitoring the condition of the 3D printed molds.

• Journal of Conservation Science
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• v.35 no.2
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• pp.159-168
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• 2019

Plasticizers, which are added to plastics, can cause exudation, which means that the plasticizer comes out from surface of the plastics. This causes the surface of plastic artworks to become sticky, and this allows dust and pollutants to become attached to the surface. Therefore, in this study, the degradation characteristics and chemical cleaning methods of each type of plasticizer are evaluated using PVC specimens. To evaluate the degradation characteristics and chemical cleaning methods, microscopic observation, chromaticity and weight measurement, and FT-IR spectroscopy were performed. The results showed that PVCs containing different plasticizers have different degradation patterns. Especially, the PVC containing TOTM showed discoloration and exudation. In the evaluation of the chemical cleaning methods, ethyl alcohol and KOH solution showed good effects, but their stability was not good. Surfactant was found to have a good cleaning effect and stability as a cleaner for exudated plasticizers.

• Journal of Conservation Science
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• v.30 no.3
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• pp.263-275
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• 2014

It's shown how to proceed the study on Manufacturing techniques & Conservation to the Iron Pot from Cheonmachong Ancient Tomb(the 155th Tomb in Hwangnam-dong). In order to investigate manufacturing techniques of the Iron Pot, some parts of the relic were gathered. After mounting, polishing and etching on the relic, analyzing the metal microstructure was conducted. Also it's conducted a SEM-EDS analysis on the nonmetallic inclusion. White iron structure was observed in the metallurgical structure inspection, SEM-EDS analysis. It seems to be dried slowly at room temperature after casting, doesn't look as particular heat treatment to improve brittleness. It is estimated that it's as the handle seam side were verified about 3cm inch wide, 1.5 thick in center of body, so 2 separate half-completed products was cast with width-type mould. The manufacturing techniques Using white cast iron structure, width-type mould are observable to the Iron Pot excavated from Sikrichong Ancient Tomb & Hwangnamdaechong grand Ancient Tomb around those were constructed the same time. It's able to recognize that it's almost identical manufacturing techniques at that time. Conservation is generically following those are survey of pretreatment, foreign material removal, stabilization, restoration and color matching in the order. cleaning & drying were added to the process as occasion demands. The strengthening treatment were difficult with artifact's volume, low concentration Paraloid NAD-10 solution was spread two or three times with a brush, surface hardening also came up with 15wt% Paraloid NAD-10 solution after the conservation was complete. There were connection & restoration for the restoration to the damage after modeling forms that it's similar to damaged parts by using the Fiber Reinforced Plastic resins(POLYCOAT FH-245, mold laminated type). Throughout this research, capitalizing on accumulations of measurements about the production technique of Iron Pot in the time of the fifth and 6th centuries is no less important than the Iron artifact's conservation for a better study in the future.

• The Korean Journal of Physiology
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• v.5 no.1
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• pp.59-69
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• 1971

Studies were undertaken on the changes in the renal blood flow by relating them with the alterations in the amplitudes in the rheogram of rabbits. The changing pattern of the electrical conductivity was recorded by means of the needle electrodes inserted into the kidney and the surrounding aluminium foil which was grounded. The Impedance Rheograph manufactured by the Narco Company was used. The small artifact which persisted after ligation of the renal vessels was subtracted from the value obtained in each pulsatile wave in the rheogram. The animals were nembutalized intravenously, 30 mg/kg. A plastic canule was inserted into the carotid artery and the arterial blood pressure was monitored continuously with the pressure transducer connected to the physiograph. Stepwise bleedings were performed on the animal. The first bleeding was between 13 to 18 ml in the amount, and it was folowed by consecutive hemorrhages, 5 or 10 ml each time. The total amount of bleeding was summed as much as 1.5-2% of the body weight. Two minutes fter each bleeding th arterial blood pressure, ECG and the rheogram were taken. That was the necessary time to obtain the stabilized picture of each parameter. After closing the bleeding process, the shed blood was retransfused into the animal and the response in the renal blood flow was observed as well as the arterial blood pressure. Particularly the presence or absence of the autoregulatory mechanism in the situation of the hemorrhage was also studied. The results obtained were as follows: 1. In 7 cases out of 22, that was about one third of the total number of experiments, the autoregulatory mechanism of the renal blood flow persisted even in acute hemorrhage, and the decreases in the renal blood flow were less than 10% of the control values even when the arterial blood pressure dropped to 66-87% of the original value obtained before the bleeding. 2. Because of the stepwise bleeding the exact blood pressure at which the renal blood flow reduced as much as one third of the control value could not be obtained. However, the results revealed that the approximate pressure, expressed as percentage of the control value, was 50-60% in 3 cases, 61-70% in 4 cases and 71-80% in 8 cases. In one case the decrease in the renal blood flow exceeded one third of the control value before the pressure dropped to 80% of the control. 3. In 19 cases the decreases in the renal blood flow exceeded one half of the control values by hemorrhage. Then the arterial blood pressure revealed less than 40% of the control value in 6-cases. In 2 cases the pressure was 51-60% of the control pressure. In 5 cases the range of bleed pressure was 61-70%, and in e remaining 6 cases the pressure ranged from 71 to 80% of e control value. 4. Out of 15 cases of retransfusion after definite decreases in the renal blood flow loller·ing the hemorrhage, 9 cases restored their renal blood flow. On the contrary 6 cases showed low values even when the shed blood was retransfused. 5. Theories concerning the mechanism of the autoregulation of the renal blood flow were reviewed for the purpose of explanation of the results obtained. However, there are much to be done before greater satisfaction