• Transactions of the Korean hydrogen and new energy society
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• v.12 no.2
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• pp.147-155
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• 2001

To measure of thermal loading in the combustion chamber of hydrogen engine with dual injection, instantaneous wall-surface temperature and unsteady heat flux of the cylinder head are measured and analyzed. The maximum wall surface temperature is shown in direct injection region which has large heat supplied. Partial and spatial temperatures have slight deviation in transient region of injection, though injection method change suddenly. All of thermal characteristics such as instantaneous temperature, temperature swing and heat flux of hydrogen engine with dual injection are remarkably higher than those of gasoline engine. It means necessity of additional countermeasure of thermal loading.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.148-148
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• 2010

Measuring the a-IGZO TFTs with various temperatures was found to induce a threshold voltage shift and a change of the subthreshold gate voltage swing. Characteristic change is dependant on a material of the substrate at the temperature from $20^{\circ}C$ to $100^{\circ}C$. The threshold voltage was shifted to the left from -2.7V to -61V on SiO2/galss. But, as the temperature increases form $20^{\circ}C$ to $100^{\circ}C$. the threshold voltage was shifted to the right from 0.85V to 2.45V.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3106-3116
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• 2022

The present work presents analysis results of the core design optimizations for an annular, prismatic High Temperature Gas-cooled Reactor (HTGR) with passive decay-heat removal features. Its thermal power is 100 MW_t and the operating temperature is 850 ℃ (1123 K). The neutronic calculations are done for the core with heterogeneous distribution of fuel and burnable poison particles (BPPs) to flatten the reactivity swing and power peaking factor (PPF) during the reactor operation as well as for control rod (CR) insertion into the core to restrain a small excess reactivity less than 1$. The next step of the study is done for evaluation of core reactivity coefficient of temperature.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.1
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• pp.49-55
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• 2008

The feasibility of ionic liquid as a novel absorbent of $SO_2$ for the separation of $SO_2$ from $SO_2/O_2$ mixture in the thermochemical IS(Iodine-Sulfur) cycle was investigated. 1,3-dimethylimidazolium methylsulfate ([DMIm]$MeSO_4$) had shown twenty five times higher solubility of $SO_2$ than that of $O_2$. The dependence of $SO_2$ solubility by [DMIm]$MeSO_4$ on temperature and $SO_2$ partial pressure was examined, which confirmed the possibility of temperature and pressure swing for the separation process. Through cyclic absorption and desorption with temperature swing the stability of [DMIm]$MeSO_4$ in the separation process was also demonstrated. As a result of the experiments carried out, $SO_2$ separation from $SO_2/O_2$ mixture with ionic liquid([DMIm]$MeSO_4$) can be applied to the thermochemical IS cycle.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.375-378
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• 2013

A reference voltage generator which is insensitive to PVT (process-voltage-temperature) variation necessary for NVM memory IPs such as EEPROM and MTP memories is designed in this paper. The designed BGR (bandgap reference voltage) circuit based on MagnaChip's $0.18{\mu}m$ EEPROM process uses a low-voltage bandgap reference voltage generator of cascode current-mirror type with a wide swing and shows a reference voltage characteristic insensitive to PVT variation. The minimum operating voltage is 1.43V and the VREF sensitivity against VDD variation is 0.064mV/V. Also, the VREF sensitivity against temperature variation is $20.5ppm/^{\circ}C$. The VREF voltage has a mean of 1.181V and its three sigma ($3{\sigma}$) value is 71.7mV.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.196-204
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• 1998

For the experimental measurement of instantaneous surface temperature of the piston of the DI mono cylinder diesel engine, the instantaneous temperature proves, data acquisition system, and grass-hopper type linkage system were developed. The instantaneous temperatures on the piston bowl, crown, lands and skirt were measured and analyzed, and the following conclusions were derived ; (i) The crank angle for the maximum instantaneous temperature during one cycle varies and moves back and forth by the measuring positions and engine speeds. (ii) The engine speeds, the positions of the measuring points and the cooling water temperature had an effect on the instantaneous temperature amplitude. (iii) The instantaneous temperature suing phenomena appeared on the temperature profiles of the piston crown, top and second land of ring, but on the temperature profiles of the parts of the third land of the fing and skirt, they didn't appear, (iv) The isothermal lines in the piston were acquired through the operation of the finite elements method using the measured temperatures as the boundary conditions.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.246-253
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• 2000

The optimal equations to predict the soil tempratures of twelve cities in the region of the southern part of the Korea such as Changhung, Cheju, Chinju, Kwangju, Masan, Miryang, Mokpo, Muan, Pusan, Sogwipo, Ulsan, Yoosu, were suggested as function of time and soil depth and the time dependent variation and soil depth dependent distribution of temperature were analyzed for the back data of the geothermal energy utilization system design and agricultural usages. The equation form is $T(x,\;t)\;=\;T_{m}\;-\;T_{so}{\cdot}Exp(-\xi){\cdot}cos{\omega}(t\;-\;t_{o}\;-\;x\;/\sqrt{2{\alpha}{\omega}}$) and it can predict the soil temperatures well with the correlation factor of 0.98 or upwards for most data. The range of mean soil temperature was $14.99~18.53^{\circ}C$ and soil surface temperature swing, 11.65~14.54 days, soil thermal diffusivity, $0.025~0.069\;m^2/day$ except Mokpo of $0.100\;m^2/day$, and phase shift, 19.66~27.81 days. During about thirty years from 1960s to 1990s, the mean soil temperature was increased by $0.04~1.25^{\circ}C$. The temperature difference depending on soil depth was not significant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.62-62
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• 2009

Electrical properties of SGS-TFT with 5/5 ${\mu}m$ channel width and length which gate insulator is made of 20nm $SiO_2$ and 80nm $SiN_x$ was fabricated and measured at various temperatures. The field-effect mobility was decreased from 86.25 to 80.42 $cm^2/Vs$ and threshold voltage also decreased from -1.5792 to -1.0492 V, when temperature is increased from room temperature to $100^{\circ}C$. Subthreshold swing, also, increased from 0.3212 to 0.4818 V/dec and $I_{on/off}$ ratio decreased from $5.05{\times}10^7$ to $6.93{\times}10^5$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.2935-2944
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• 2000

Gas tungsten arc(GTA) welding is used to rrpiar the seat ring in swing type check valve in power plant because of its high weld quality. In order to automate the welding process, it is needed to analyze the process of inside pipe girth welding. In this study, the shapes of weld bead on pipe inside and outside were predicted and its validity was investigated. On the assumption that the welding arc had a bivariate gaussian distribution, analytical solution was derived to predict the temperature distribution in pipe weld using mapping under consideration of physical relationships. The size of weld bean could be predicted from this equation and its accuracy was verified by experiments.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.96-103
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• 2005

One of the major problems limiting the accuracy of piezoelectric transducers fur cylinder pressure measurements in an internal combustion (IC) engine is the thermal shock. Thermal shock is generated from the temperature variation during the cycle. This temperature variation results in contraction and expansion of the diaphragm and consequently changes the force acting on the quartz in the pressure transducer An empirical equation for compensation of the thermal shock error was derived from consideration of the diaphragm thermal deformation and actual pressure data. The result indicate that the thermal shock equation provides reliable correction based on known surface temperature swing.