• ETRI Journal
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• v.37 no.1
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• pp.97-106
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• 2015

In this paper, MOS-triggered silicon-controlled rectifier (SCR)-based electrostatic discharge (ESD) protection circuits for mobile application in 3.3 V I/O and SCR-based ESD protection circuits with floating N+/P+ diffusion regions for inverter and light-emitting diode driver applications in 20 V power clamps were designed. The breakdown voltage is induced by a grounded-gate NMOS (ggNMOS) in the MOS-triggered SCR-based ESD protection circuit for 3.3 V I/O. This lowers the breakdown voltage of the SCR by providing a trigger current to the P-well of the SCR. However, the operation resistance is increased compared to SCR, because additional diffusion regions increase the overall resistance of the protection circuit. To overcome this problem, the number of ggNMOS fingers was increased. The ESD protection circuit for the power clamp application at 20 V had a breakdown voltage of 23 V; the product of a high holding voltage by the N+/P+ floating diffusion region. The trigger voltage was improved by the partial insertion of a P-body to narrow the gap between the trigger and holding voltages. The ESD protection circuits for low- and high-voltage applications were designed using $0.18{\mu}m$ Bipolar-CMOS-DMOS technology, with $100{\mu}m$ width. Electrical characteristics and robustness are analyzed by a transmission line pulse measurement and an ESD pulse generator (ESS-6008).

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.168-171
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• 1988

The p-n homo junction diode of the III-V ternary alloy semiconductor $In_{1-x}Ga_xP$ : S grown by the temperature gradient solution (TGS) was fabricated by Zn-diffusion, and it's characteristics was investigated. The carrier concentration of $In_{1-x}Ga_xP$ doped with sulfur, 0.5 mol %, was $1{\times}10^{17}cm^{-3}$ and the mobility was varied with the composition. In the case that the diffusion time was constant as 30 minutes. The temperature dependence of diffusion coefficient was decreased from D= $4.2{\times}10^{-5}$ exp (-1.74/$k_{B}T$) to D= $2.5{\times}10^{-5}$ exp (-3.272/$k_{B}T$) with increasing of composition $\times$ from 0.43 to 0.98. The major peak of E.L spectrum was due to D-A pair recombination and the peak intensity was increased with the increasing of input current. And the E.L intensity was decreased with the increasing temperature, and shift to the long wavelength. The luminescence efficiencies measured at $5^{\circ}C$, atmosphere temperature, was decreased from $2.6{\times}10^{-4}$% to $9.49{\times}10^{-6}$ % with increasing of composition it from 0.39, direct transition region, to 0.98, indirect transition region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1101-1109
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• 2004

Experimental measurements of flame structure and soot characteristics were performed fur ethene inverse diffusion flames (IDF). IDF has been considered as the excellent flow field to study the incipient soot because soot particle do not experience the oxidation process. In this study, LIF image clarified the reaction zone of IDF with OH signal and PAH distribution. laser light scattering technique also identified the being of soot particle. To address the degree of soot maturing, C/H ratio and morphology of soot sample were investigated. From these measurements, the effect of flow residence time and temperature on soot inception could be suggested, and more details on soot characteristic in the IDF was determined according to fuel dilution and flame condition. The fuel dilution results in a decrease of temperature and enhancement of residence time, but the critical dilution mole fraction is existed for temperature not to effect on soot growth. Also, the soot inception evolved on the specific temperature and its morphology are independent of the fuel dilution ratio of fuel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.4
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• pp.504-511
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• 2000

PIV(Particle Image Velocimetry) is a recently developed technique for visualizing the fluid velocity fields. Because it has several advantages over the LDV(Laser Doppler Velocimetry), it became one of the most popular diagnostic tools in spite of its short history. However, its application to combustion is restricted by some problems such as flame illumination, scattered light refraction, particle density variation due to heat release, the combined effect of abrupt change in particle density and fluid velocity on flame contour, and thermophoresis which is particle lagging due to temperature gradient. These problems are expected to be originated from the non-continuous characteristics of flames and the limitations of particle dynamics. In the present study, these problems were considered for the visualization of the instantaneous coaxial hydrogen diffusion flame. And the instantaneous flame contour was detected using particle density difference. The visualized diffusion flame velocity field shows its turbulent and meandering nature. It was also observed that the flame is located inside the outer shear layer and flame geometry is largely influenced by the vorticity.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.123-128
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• 2002

The synergistic effect of ethylene/propane and ethylene/methane mixtures on soot formation is studied experimentally with a concentric co-flow burner. The integrated soot volume fractions, laser light scattering signal and PAH concentrations are measured for different fuel supply configurations. The synergistic effect in ethylene/propane diffusion flames is found to be affected not only by the composition of mixture but also by the way of mixing. Comparing to the homogeneously mixed ethylene/propane case, the increase of soot formation is observed when propane is supplied through the inner nozzle, while the decrease is observed when propane is supplied through the outer nozzle. However, the measured PAH concentration distributions are inconsistent with the current view of the synergistic effect of ethylene./propane mixture on soot formation. Virtually no synergistic effect is observed in ethylene-methane flames regardless of the fuel supply configuration, which suggests the important role of $C_3$ species produced during the propane pyrolysis process for the synergistic effect.

• Polymer(Korea)
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• v.30 no.5
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• pp.422-425
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• 2006

Due to their periodic helical structure, cholesteric liquid crystals (CLC) have a unique ability to selectively reflect visible light. CLC films reflecting a broad wavelength band were prepared by inducing a pitch gradient in CLC layers through a diffusion of small molecules and through a thermal mixing of cyclic siloxane CLC molecules with different pitch lengths. Various pitch gradients in the CLC cell were observed using UV/Vis spectrometer and SEM technique.

• Journal of Power Electronics
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• v.16 no.1
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• pp.238-248
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• 2016

The state-of-charge (SOC) and state-of-health (SOH) estimation of batteries play important roles in managing batteries for automotive applications. However, an accurate state estimation of a battery is difficult to achieve because of certain factors, such as measurement noise, highly nonlinear characteristics, strong hysteresis phenomenon, and diffusion effect of batteries. In certain vehicular applications, such as idle stop-start systems (ISSs), significant errors in SOC/SOH estimation may lead to a failure in restarting a combustion engine after the shut-off period of the engine when the vehicle is at rest, such as at a traffic light. In this paper, a dual extended Kalman filter algorithm with a dynamic equivalent circuit model of a lead-acid battery is proposed to deal with this problem. The proposed algorithm adopts a battery model by taking into account the hysteresis phenomenon, diffusion effect, and parameter variations for accurate state estimations of the battery. The validity of the proposed algorithm is verified through experiments by using an absorbed glass mat valve-regulated lead-acid battery and a battery sensor cable for commercial ISS vehicles.

• Journal of the Korean Society of Food Culture
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• v.34 no.4
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• pp.411-423
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• 2019

This study conducted qualitative research through in-depth interviews on the diffusion process of Korean food in accordance with the length of residence of Chinese students in Korea. As the analysis method, the qualitative analysis method such as NVivo12.0 was used, and the analysis was performed through word frequency, word cloud, and coding matrix. The images of taste of Korean food were revealed as 'Spicy', 'Sweet', and 'Light taste' by both short-term Chinese residents and long-term Chinese residents. The long-term Chinese residents showed their dissatisfaction with the institutional food, and they also pointed out the importance of the matter of cooking for quick adaptation to life in Korea. The long-term Chinese residents also thought of Korean food as 'High-fiber food', and this was influenced by the 'Less-oil' cooking method of Korean food, which is different from the cooking method of Chinese food. The length of residence was used as a main variable of this study, and it was one of the factors having positive effects on the diffusion of Korean food and acculturation. It would be difficult to generalize the results because this study used the convenience sampling method and snowball sampling.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.53-59
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• 2006

This study is measurement of radicals in gas & light oil diffusion flame focused on burner exit. The goal of this study is to analyse the relationship between flame chemiluminescence($OH^{\ast}$, $CH^{\ast}$, $C_2^{\ast}$) intensities and flame conditions. The investigation performed turbulent diffusion flame of commercial burner in varying the excess air ratio from 1.0 to 1.8. The optical emissions were measured by photomultiplier(PMT) using optical band pass filter and spectrometer system. The effects of excess air ratio and NOx emission characteristics on the radical emission intensities were investigated experimentally.

• Journal of the Korean Society of Combustion
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• v.8 no.4
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• pp.1-8
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• 2003

In this study, the quantification of soot particles in laminar diffusion flame with LII/LIS methods was performed. In these quantification, soot diameter, number density and volume fraction are included. For the quatification of soot particles, calibration tests are needed and the development of algorithm has to be performed. So, in this study, extinction and scattering test at co-flow burner were performed to acquire calibration data. And algorithm for LII/LIS simultaneous measurement for the quantification of soot were developed. The algorithm, which was the quantification of simultaneous photographing using one ICCD camera, to measure LII/LIS signal simultaneously, the best fitted light intensity and acquisition time was needed.