• Journal of Chest Surgery
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• v.16 no.4
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• pp.452-457
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• 1983

Transposition of great arteries is relatively common cyanotic heart disease excluding TOF and is divided to two groups: complete TGA and congenitally corrected TGA. We experienced operations in 3 cases of TGA, the 1st case was 12 year-old male: TGA[SDD] + VSD+PS and treated with Rastelli`s operation, but expired due to low cardiac output syndrome postoperatively. The 2nd case,13 year-old male was also TGA[SDD]+VSD+PS and treated with Rastelli`s operation with good operative result. The 3rd case was 18-year old male: congenitally corrected TGA[SLL]+VSD+ PA+ASD and operation was done according to the met. hod reported by Danielson et al in 1980. Post-operative AV block led to implantation of permanent epicardial pacemaker with good result.

• Journal of Oriental Neuropsychiatry
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• v.19 no.3
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• pp.265-276
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• 2008

Transient global amnesia(TGA) is a clinical syndrome characterized by sudden, temporary dysfunction of anterograde and recent retrograde memory without other neurologic deficits. Different hypotheses have been considered for its etiology, but it still remains obscure. Recently the diffusion-weighted magnetic resonance imaging(DWI), has been considered as the sensitive tool to detect small punctate hyperintense lesions in the hippocampus in transient global amnesia(TGA). We report two TGA cases, all of them answers to TGA clinical criteria, and one of them showed two dot like high signal intense foci in Rt. hippocampus on DWI.

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.1
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• pp.45-53
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• 2002

Objectives: This study investigated alterations in regional cerebral blood flow (rCBF) in patients with transient global amnesia (TGA) using statistical parametric mapping 99 (SPM99). Methods: Noninvasive rCBF measurements using 99mTc-ethyl cysteinate dimer (ECD) SPECT were performed on 8 patients with TGA who have ongoing symptoms and 17 age matched controls. The relative rCBF maps in patients with TGA and controls were compared. Results: In patients with TGA, significant decreased rCBF was found along the L superior temporal extending to L parietal region of the brain and L thalamus. There were areas of increased rCBF in the R temporal, R frontal region and R thalamus. Conclusion: We could demonstrate decreased perfusion in left cerebral hemisphere and increased perfusion in right cerebral hemisphere in patients with TGA using SPM99. The imbalanced change of rCBF between bilateral cerebral hemisphere in patients with TGA might suggest that imbalanced neuronal activity between the bilateral hemispheres may have strong relationship to the pathogenesis of the TGA. For quantitative SPECT analysis in TGA patients, we recommend SPM99 rather than the ROI method because of its definitive advantages.

• Elastomers and Composites
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• v.44 no.3
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• pp.269-273
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• 2009

A study on the life-time expectation of a CR-modified NR rubber composite through the change of thermal degradation characteristics was performed using both isothermal thermogravimetric analysis (TGA) and thermomechanical analysis (TMA). Master curves at reference temperature of $90^{\circ}C$ could be obtained with shift factor $a_T$, which was determined empirically using Time-Temperature Superposition Principle (TTSP). Activation energies could be calculated from the slope of Arrhenius plot of shift factor and showed similar values of $E_{a,TGA}$= 41.2 and $E_{a,TMA}$= 54.5 kJ/mol, respectively. It was considered from the results that chemical degradation resulting weight loss of the sample might be closely related to a physical degradation such as the dimensional change of the sample.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.360-367
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• 2005

PMMA has been used extensively worldwide as industrial and construction materials due to its excellent material properties. When PMMA is subject to thermal degradation, unit of monomers are detached from polymer chain and this phenomena is called unzip reaction. Therefore, PMMA thermally degrades into its monomer. Characteristics of thermal degradation of PMMA has been investigated using TGA in this research as a basic study for recovery of MMA.

• Elastomers and Composites
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• v.50 no.1
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• pp.18-23
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• 2015

Vinyl acetate (VA) contents of poly(ethylene-co-vinyl acetate) (EVA) analyzed by infrared spectroscopy (IR), nuclear magnetic spectroscopy (NMR), and thermogravimetric analysis (TGA) were compared. Four grade EVAs supplied by Aldrich Co. and four grade EVAs manufactured by DuPont Co. were used. For IR analysis, VA contents were determined using calibration curve (absorbance ratio of $1739cm^{-1}/2922cm^{-1}$ or $609cm^{-1}/1464cm^{-1}$) of reference EVAs. Correlation coefficients of the calibration curves were not sufficiently high ($r^2{\leq}0.96$). For NMR analysis, VA contents were determined using peaks of $CH_3$, $CH_2$, and CH. VA contents determined by NMR analysis were less than those marked by suppliers more than 10%. For TGA, VA contents were determined using weight loss through deacetylation. VA contents determined by TGA were slightly different with those marked by suppliers. Difference in the VA contents determined by different analytical methods was discussed, and difference in the analytical results according to the EVA suppliers was also examined.

• Elastomers and Composites
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• v.56 no.1
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• pp.1-5
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• 2021

Tire and road wear particles (TRWPs) were collected from road dust and thermogravimetric analysis (TGA) was performed to measure the content of tire wear particles (TWPs) in the TRWPs. The TGA thermograms of TRWPs showed two weight loss steps associated with polymer decomposition including weight loss after 480℃ which may be due to road wear particles. Different samples gave different TGA thermograms because the types and contents of the road wear particles attached to the TWPs should be different from each other, and each TWP might have different composition. The TGA results of the model asphalt pavement wear particles, with (volatile organics + polymers + carbon black) : ash = 33.5 : 66.5, was applied to the TRWP results, and the TWP contents of TRWPs were found to be 50-65%. The zinc oxide content in the rubber compound was negligible.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.352-357
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• 2012

Techniques of thermal analyses such as DSC and TGA have been used in the study of activation energy (Ea) and frequency factor (A) depending on the particle size of RDX and HMX. Activation energy and frequency factor were calculated by Kissinger's method and Vyazovkin's method. As the particle size of RDX increased, TGA showed activation energy increased, but DSC didn't show. However, In case of HMX, as the particle size increased, both of DSC and TGA showed increase in activation energy. Moreover, Vyazovkin's method can obtain activation energy and mechanism according to decomposition of RDX and HMX.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.50-55
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• 2003

Radiation degradation of crosslinked polyethylene(XLPE) was investigated using thermogravimetric analysis(TGA), The results of TGA were compared with FT-IR, melting temperature, oxidation induction time, and elongation at break on the XLPE exposed by $\gamma$-ray. 5% decomposition temperature of $\gamma$-ray irradiated XLPE showed similar tendencies with the case of elongation at break. Both properties agreed below 1000 KGy, however, did not show any remarkable characteristics above 1000 kGy, these properties can be useful to evaluate the radiation degradation of XLPE for only low irradiated region. Above 1000 kGy, the thermal decomposition activation energy showed decreased, on the contrary, increasing below 1000 kGy. Compared with FT-IR spectrum of irradiated XLPE, it was confirmed that the oxidation reaction was still occurring below 1000 kGy. Radiation degradation of XLPE was dependent upon the irradiation doses, TGA can be a useful tool to evaluate the degradation.

• Analytical Science and Technology
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• v.24 no.3
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• pp.168-172
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• 2011

The iron frame of building could be collapsed or bent at $500^{\circ}C$. Therefore the fire-resistant paint should be applied for safety. This study performed the comparative analysis to show the characteristics of fireresistant paint. And then 12 products of fire resistant paint and 6 products of paints were used as samples. And the samples were analyzed by TGA (Thermogravimetric Analyzer) as analyzer for measuring the variation of weight on temper of weight by heating. When TGA analyzer could measure the variatiature, and FT-IR was measured for analyze gas components on variation on of weight by heating on 12 products of fire resistance, the samples showed to decrease 40% of weight to $800^{\circ}C$, and because paints had 50% to 40% of loss weight, it showed to be equal with loss weight of fire resistance paint on high temperature or was lower loss weight than it of fire resistance paints. However number 6 sample of fire resistance paints could show to decrease 20% of total weight on $800^{\circ}C$. And then in the case of FT-IR, fire resistance paints could show to have the high intensity of $CO_2$ spectrum as complete combustion. However paints could show to have the lower intensity of $CO_2$ spectrum, have the higher intensity of water spectrum. Therefore the TGA graph of result could be much different until $250^{\circ}C$. When it was burned, FT-IR spectrum could show to confirm the characteristics of fire resistance paints, and the characteristic could be confirmed on inorganic paint of fire resistance by weight loss of TGA.