• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.570-575
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• 2006

In this paper, we have investigated thermal properties by changing the content of carbon nanotube, which is component part of semiconductive shield in underground power transmission cable. Heat capacity (${\Delta}H$), glass transition temperature (Tg) and melting temperature (Tm) were measured with the samples of eight, through DSC (Differential Scanning Calorimetry), and the measurement ranges of temperature selected from $-100[^{\circ}C]\;to\;100[^{\circ}C]$ with heating temperature selected per $4[^{\circ}C/min]$ Also, high temperature, heat degradation initiation temperature, and heat weight loss were measured by TGA (Thermogravimetric Analysis) in the temperature from $0[^{\circ}C]\;to\;700[^{\circ}C]$ with rising temperature of $10[^{\circ}C/min]$. As a result, the Glass transition temperatures of the sample were showed near $-20[^{\circ}C]{\sim}25[^{\circ}C]$, and the heat capacity and melting temperature from the DSC was increased according to increasing the content of carbon nanotube, while, thermal diffusivity was increased according to increasing the content of carbon nanotube. Also, heat degradation initiation temperature from the TGA results was increasing according to increasing the content of carbon nanotube with CNT/EEA. Therefore, heat stabilities of EVA, which contained the we VA (vinyl acetate), showed the lowest.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.421-424
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• 2011

Thermal Analyses are conducted to measure various factors of a liquid fuel required for numerical analysis. Thermal Analyses are divided into two different methods of TGA (Thermo Gravimetric Analysis) and DSC (Differential Scanning Calorimetry). Non-isothermal experimental results are analyzed using by TGA. The results are filtered by a Freeman Carroll method. At the same time, chemical parameters of unknown liquid fuel, activation temperature and reaction order are measured to 6128.2 K and 1.4, respectively. Furthermore, the parameters can be obtained by various mathematical methods. It is found that tha parameters depend on the processing method.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.180-189
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• 2017

Pharmaceutical co-crystals primarily to improve the solubility as well as stability of insoluble drug are to be investigated more intensively for IMDs as US FDA has reclassified co-crystal as a special case of solvates in August this year. In this study, we proposed a mechanism of indomethacin-saccharin co-crystal formation and the creation of transient indomethacin meta-stable form using in-line monitoring tools with the addition rate of anti-solvent as a critical process parameter. Among various instruments, we combined PVM (particle vision measurement) and FBRM (focused beam reflectance measurement) for the in-line monitoring of anti-solvent co-crystallization process. The off-line characterization of resulting powders was carried out employing the PXRD (powder x-ray diffraction) and DSC (differential scanning calorimeter). It was observed that the pathway to the final IMC-SAC co-crystal was significantly dependent upon the anti-solvent addition rate. The process conditions to obtain high quality co-crystal powder effectively were established. Consequently, we concluded that in-line monitoring combing the PVM and FBRM should be useful for the in-line monitoring of pharmaceutical co-crystallization processes.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.633-640
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• 2010

This study was performed to get basic information about properties of high blaine cement for shotcrete use. Particle size distribution, setting time and compressive strength test, analysis like as SEM, DSC thermal analysis, XRD was carried out to investigate principle properties of high blaine cement. Setting time of high blaine cement was shorter and compressive strength was higher than those of ordinary portland cement (OPC). Results of analysis showed early hydration products of high blaine cement is smaller and spread widely due to increased specific surface. From the SEM observation and analysis of DSC and XRD results, it was seen that the aluminates accelerators promoted calcium aluminium hydrates while the alkali free accelerators increased ettringite and monosulfates formation. Strength and setting time measurement of cement paste with aluminate accelerator is more effective than the alkali free accelerator in reducing the setting time and increasing early strength while alkali free accelerator is more effective in increasing the strength after 7 days.

• Polymer(Korea)
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• v.24 no.3
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• pp.314-325
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• 2000

Thermal degradation of thermoplasitc polyurethane modified polycarbonate has been investigated by means of DSC, GPC and FT-IR techniques. The polyurethanes used in this study are TPU-35 and TPU-53 containing 35.5 and 53.4 wt% of hard segments, respectively. The more content of hard segment, the higher the glass transition temperature (T$_{g}$) of TPU was observed. On the other hand, the T$_{g}$ of the TPU modified PC decreased with the content of TPU and the annealing temperature regardless of the hard segment contents. The latter behavior nay arise from the thermal degradation of TPU upon annealing process: the observed thermal degradation temperatures were at 240 and 25$0^{\circ}C$ for the PC/TPU-35 and PC/TPU-53, respectively. The molecular weight, molecular weight distribution and viscosity agree well with the DSC measurement, which implicates a thermal degradation of TPU. In addition, thermal stability of the TPU modified PC linearly decreased with an incorporation of TPU. Transesterification or any interaction was not observed using FT-IR: the evidence was no frequency shift or any variance betwere the carbonyl stretching and NH group. For the specimens prepared below the degradation temperature, the enhancement of the thickness dependent impact strength of the PC/TPU blend was observed, and the morphology of the two blends was compared.d.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1719-1721
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• 1996

This paper describes the thermally stimulated current(TSC) of PAAS spin coated film and the electrical properties of pre TSC measurement and after TSC test specimens. The TSC measurement were performed from room temperature to about $280^{\circ}C$ and the temperature was increased by $5^{\circ}C/min$ automatically. It shows that two peaks of TSC are observed at about $50^{\circ}C$ and about $160^{\circ}C$. Result of this measurement indicate that one peak; $50^{\circ}C$ is from alkyl group; other peak at $160^{\circ}C$ is due to alkyl and C-O group of PAAS. Addition to larger peak at about $160^{\circ}C$ is due to dipolemoment of PAAS film. This result is proved by DSC measurement of PAAS film. The electrical properties of pre and after TSC were measured by currant-voltage(l-V) characteristics. The current-voltage characteristics after TSC specimens are increased the conductivity. The electrical properties of pre-after TSC measurement specimen is in the middle of imidization of PAAS. Because of this result a thermal imidization was performed at $300^{\circ}C$ for 1 hour.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.1
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• pp.6-10
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• 2006

To improve mean-life and reliability of power cable, we have investigated specific heat (Cp) and thermal conductivity of XLPE insulator and semiconducting materials in 154(kV) underground power transmission cable. Specimens were respectively made of sheet form with EVA, EEA and EBA added $30[wt\%],$ carbon black, and the other was made of sheet form by cutting XLPE insulator in 154(kV) power cable. Specific heat (Cp) and thermal conductivity were measured by DSC (Differential Scanning Calorimetry) and Nano Flash Diffusivity. Specific-heat measurement temperature ranges of XLPE insulator were from $20[^{\circ}C]\;to\;90[^{\circ}C],$ and the heating rate was $1[^{\circ}C/mon].$ And the measurement temperatures of thermal conductivity were $25[^{\circ}C],\;55[^{\circ}C]\;and\;90[^{\circ}C].$ In case of semiconducting materials, the measurement temperature ranges of specific heat were from $20[^{\circ}C]\;to\;60[^{\circ}C],$ and the heating rate was $1[^{\circ}C/mon].$ And the measurement temperatures of thermal conductivity were $25[^{\circ}C],\;55[^{\circ}C].$ In addition we measured matrix of semiconducting materials to show formation and growth of carbon black in base resins through the SEM. From these experimental results, both specific heat and thermal conductivity were increased by heating rate because volume of materials was expanded according to rise in temperature.

• Journal of Sericultural and Entomological Science
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• v.34 no.2
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• pp.41-51
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• 1992

In this thesis, both soap and enzymatic degumming method were adopted and the optimum degumming conditions were obtained. Difference between the two degumming methods in silk fiber state was investigated and analyzed on the basis of the results of physical testings, polarizing microscopy, scanning electron microscopy, viscosity measurement, (${\alpha}$＋$\varepsilon$) amino group contents measurement, birefringence measurement, amino acid analysis, thermal analysis, infrared spectroscopy and x-ray diffraction analysis. The results obtained were summarized as follows; Physical test results of the degummed silk fiber showed that the tenacity and the elongation of enzymatic degummed silk fiber were lower than those of soap degummed fiber. But SEM observation and amino acid analysis showed almost the same tendency in the two degumming methods. The viscosity of enzymatic degummed silk fiber was lower than that of soap degummed fiber, but (${\alpha}$＋$\varepsilon$) amino group contents was higher in the enzymatic degummed fiber. It can be suggested that the enzymatic degummed silk fibroin was more degraded than the soap degummed fibroin. The birefringence, endothermic temperature of DSC spectrum, IR crystallinity and X-ray lateral order factor of enzymatic degummed silk fiber were higher than those of soap degummed fiber. It seems that the enzymatic degummed silk fiber has the higher crystallinity than that of soap degummed one according to the above results. However, it can be inferred that these differences between soap and enzymatic degummed fiber would be lessened if pretreatment and aftertreatment were included in the enzymatic degumming process.

• Environmental Engineering Research
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• v.11 no.5
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• pp.257-265
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• 2006

The purpose of research is to mix the fly ash from municipal solid waste incinerator in the recycled Polypropylene and to recycle. The specimen was produced by mixing 20 wt.% of MSWI fly ash at maximum in the recycled Polypropylene and the particle size analyzer, DSC, TGA, SEM and UTM instruments were used to analyze the physical chemical properties of the specimen. As a result of measurement, the average particle size of MSWI fly ash was $18.08\;{\mu}m$. In TGA analysis, the temperature of specimen S-5 at 50% of weight decrease was risen by $7^{\circ}C$ higher than specimen S-1. In UTM measurement, specimen S-2 showed the maximum strength for tensile strength and specimen S-3 showed the maximum strength for flexural strength. But, impact strength was decreased according to the increasing proportion of MSWI fly ash. In conclusion, when the proper amount of MSWI fly ash was added to the recycled Polypropylene, thermal endurance, tensile strength and flexural strength could be increased, but impact strength was decreased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.8
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• pp.749-754
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• 2008

A large number of studies on the various characteristics of epoxy-layered silicate nanocomposites, such as electric and mechanical, morphology have been conducted and contributed to improve their characteristics. However, studies on the effects of its thermal conductivities in the thermal properties are not enough, even though there are some excellent evaluations for its insulation performances. Thermal properties will cause thermal degradation and significantly affect the reliability of these epoxy-layered silicate nanocomposites. In the results of the analysis of epoxy-layered silicate nanocomposites $T_g$ for various types of organoclays (10A, 15A, 20A, 30B, and 93A), it showed an excellent thermal property of 10A. Also, it represented low values in storage modulus and mechanical Tan (Delta) at a high temperature section 140$^{\circ}C$ and excellent thermal properties due to its movement to the high temperature section in the case of the property of 10A in the measurement of DMA elastics and mechanical losses. In the results of the measurement of thermal conductivities, power ultrasonic applications represented a significant increase in thermal conductivities in the case of the applications of power ultrasonic and planetary centrifugal mixers. Based on these results, it is necessary to perform related studies because it can be applied as useful materials for future power facilities applications in mold and impregnate insulation.