• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.2
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• pp.85-90
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• 2003

In this work $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}$ : $Co^{2+}$ single crystals were grown by the chemical transport reaction method and the structure of $Cd_{4}GeSe_{6}$ and $Cd_{4}GeSe_{6}$ : $Co^{2+}$ single crystals were monoclinic structure. The temperature dependence of optical energy 9ap was fitted well to Varshni equation. Also, the entropy, enthalpy and heat capacity were deduced from the temperature dependence of optical energy gap.

• Publications of The Korean Astronomical Society
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• v.15 no.spc2
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• pp.27-35
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• 2000

The investigation of the space environment requires the use of experimental and theoretical tools and resources in order to perform the research task. Understanding of these research tools is imperative for proper interpretation of the results. In this paper, we discuss on research tools that are widely used in the field of aeronomy; Fabry-Perot interferometer and Michelson interferometer. These instruments have been used extensively as passive optical devices, spectrally monitoring the natural atmospheric emissions (airglow). This function has made both instruments valuable tools in upper atmospheric studies since they provide the ability to determine the dynamic and thermodynamic properties of the upper atmosphere by monitoring naturally-occuring emission.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.429-436
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• 1991

Silicon carbide has been grown by a chemical vapor deposition (CVD) technique using CH3SiCl3 and H2 gaseous mixture onto a graphite substrate. Based on the thermodynamic equilibrium studies and the suggestion that the deposition rate of SiC is controlled by surface reaction theoretical kinetic equation for CVD of silicon carbide has been proposed. The proposed theoretical kinetic equation for CVD of silicon carbide agreed well with the experimental results for the variation of the deposition rate as a function of the partial pressure of reactant gases. The Vikers microhardness of the SiC layer was about 3000∼3400 kg/$\textrm{mm}^2$ at room temperature.

• Journal of the Korean Society for Heat Treatment
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• v.9 no.4
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• pp.243-251
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• 1996

Dilatometric experiment and thermodynamic calculation have been performed to determine $M_s$, $A_s$ and driving forces for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation of Fe-Mn alloys. The transformation temperatures($M_s$, $A_s$, $T_o) were decreased with increasing manganese content and were newly formulated as a function of manganese content. Driving force for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation was increased from -75J/mole to -105J/mole with increasing manganese content from 15wt.% to 25wt.%. Transformation temperature hysteresis($A_s-M_s$) was also increased from 50K to 80K with increasing mangenese content from 15wt.% to 25wt.%. The small driving force(-75J/mole~-105J/mole) and small ${\Delta}T$(50K~80K) for ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation indicated that Fe-Mn alloys behave like thermoelastic martensitic alloys : We would like to call them semi-thermoelastic martensitic alloys.

• Bulletin of the Korean Chemical Society
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• v.28 no.7
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• pp.1183-1186
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• 2007

A shake-flask method was used to determine the n-octanol/water partition coefficients of sulfamethazine, sulfadimethoxine, sulfamethoxydiazine, sulfamonomethoxine, sulfamethoxazole, sulfaquinoxaline and sulfachloropyrazine from (298.15 to 333.15) K. The results showed that the n-octanol/water partition coefficient of each sulfonamide decreased with the increase of temperature. Based on the fluid phase equilibrium theory, the thermodynamic relationship of n-octanol/water partition coefficient depending on the temperature is proposed, and the changes of enthalpy, entropy, and the Gibbs free energy function for sulfonamides partitioning in n-octanol/ water are determined, respectively. Sulfonamides molecules partitioning in n-octanol/water is mainly an enthalpy driving process, during which the order degrees of system increased. The temperature effect coefficient of n-octanol/water partition coefficient is discussed. The results show that its magnitude is the same as that of values in the literature.

• Journal of Hydrogen and New Energy
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• v.29 no.2
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• pp.163-169
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• 2018

The present article discusses about the measurement techniques of acoustic impedance that becomes one of the important acoustic characteristics of various boundaries found inside of propulsion systems. Acoustic characteristics including acoustic impedance and reflection coefficient can be often assessed and estimated by use of the two-microphone method. Theoretical expressions of acoustic impedance and reflection coefficient measured in an impedance tube are presented for both cases with mean flow and without flow, and the practical application of the method through calibration is also provided. The acoustic impedance and the reflection coefficient are related with axial locations of microphones, thermodynamic characteristics of gas inside, and the transfer function between the pressure wave measurements at multiple locations.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.135-141
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• 1972

In the past years, a number of theories have been published to elucidate the structure of liquid water. common to most of these theories is that water mainly consist of several different kinds of clusters and also hydrogen bonds in water may be bent to some degree. Recentrly, in a series of paper, Jhon and Eyring successfully explained thermodynamic, dielectric, surface and transport properites of water, assuming that it contains small domains of about 46 molecules. According to the theory, the cluster size does not change with temperature, but the cluster concentration changes. In this paper, the potential function for the hydrogen bond, the dispersion energy and dipole-dipole interaction terms. The calculated results show that the domain of nearly 46 molecules is energetically most probable, and its size is independent of temperature. And also, we evaluated the effect of angel variation of the bent hydrogen bond. In addition, the relaxation energy different for ice and water is also explained by this method.

• Progress in Superconductivity and Cryogenics
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• v.6 no.2
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• pp.35-39
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• 2004

The split-type free displacer Stirling refrigerators have been widely used for the cooling of infrared sensors and HTS filters. The thermodynamic and electric performance of the Stirling refrigerator is depending on the design and operating parameters. In the Stirling refrigerator with a free displacer, the refrigeration power is a function of the pressure wave in the expansion space, dynamics of a displacer, driving frequency, and etc.. In this study, the analysis of the small Stirling refrigerator was performed to investigate the effects of design parameters on the cooling capacity. The results show the effects of charging pressure, driving frequency, cold end temperature, natural frequency of a displacer and volume of expansion space on the performance of the Stirling refrigerator.

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.143-148
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• 2015

In some pathogenic bacteria, there are RNA thermometers, which regulate the production of virulence associated factors or heat shock proteins depending on temperature changes. Like a riboswitches, RNA thermometers are located in the 5'-untranslated region and involved translational gene regulatory mechanism. RNA thermometers block the ribosome-binding site and start codon area under the $37^{\circ}C$ within their secondary structure. After bacterial infection, increased the temperature in the host causes conformations changes of RNA, and the ribosome-binding site is exposed for translational initiation. Because structural differences between open and closed forms of RNA thermometers are mainly mediated by base pairing changes, NMR spectroscopy is a very useful method to study these thermodynamically changing RNA structure. In this review, we briefly provide a fundamental function of RNA thermometers, and also suggest a proper NMR experiments for studying RNA thermometers.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.82-84
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• 2006

최근의 생물학적인 연구에 DNA microarray가 널리 쓰이고 있기 때문에, 이러한 DNA microarray를 구성하는데 필요한 probe design 작업의 중요성이 점차 커져가고 있다. 이 논문에서는 probe design 문제를 thermodynamic fitness function이 2개인 multi-objective optimization 작업으로 변환한 뒤, ${\epsilon}$-multiobjective evolutionary algorithm을 이용하여 probe set을 찾는다. 또한, probe 탐색공간의 크기를 줄이기 위하여 각 DNA sequence의 primer 영역을 찾는 작업을 진행하며, 사용자가 직접 프로그램을 테스트할 수 있는 웹사이트를 제공한다. 실험 대상으로는 mycoides를 선택하였으며, 이 논문에서 제안된 방법을 사용하여 성공적으로 probe set을 발견할 수 있었다.