• Journal of IKEEE
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• v.17 no.4
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• pp.531-536
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• 2013

The impact of UV irradiation process on the AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistor was investigated. Due to the high intensity UV irradiation before the gate dielectric deposition, the conductivity of AlGaN/GaN structure and the drain saturation current of the transistor increased by about 10 %. However, the pinch off characteristics of transistor was severely deformed by the process. By comparing the electrical characteristics of the transistors, it was proposed that the high intensity UV irradiation formed a sub-channel under the two dimensional electron gas of AlGaN/GaN structure even without additional impurity injection.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.93-100
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• 1991

For determination the optimum manufacturing condition Fe4N powder for magnetic recording media, we have studied the following important conditions : the effect of particle size of metal powder on the nitridation, the condition of nitridation on the formation and magnetic properties of Fe4N, and stability of Fe4N powder against temperature and change on standing. The results can be summarized as : 1) Single phase Fe4N is formed at 50v/o of ammonia concentration during the nitridation reaction, 2) Single phase Fe4N is formed above 40$0^{\circ}C$, 15min regardless of the metal powder sizes, 3) Coercivity and saturation magnetization of Fe4N powder almost constant value until 20 day-passing from preparation date.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.741-753
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• 2008

This paper explores the throughput performance of CSMA/CA-based DCF protocol over both ideal channels and fading channels with payload size at the MAC layer in the 802.11a wireless LAN. In the ideal channel, there are no errors and at the transmission cycle there is one and only one active station which always has a packet to send and other stations can only accept packets and provide acknowledgements. In the fading channel, bit errors appear in the channel randomly and the number of stations is assumed to be fixed. And each station always has packets for transmission. In other words, we operate in saturation conditions. Up to now conventional research work about DCF throughput analysis of IEEE 802.11 a wireless LAN has been done over the ideal channel, but this paper is done over the Rayleigh/Ricean fading channel. So, the ratio of received average energy per bit-to-noise power spectral density $E_b/N_o$ is set to 25 dB and the ratio of direct-to-diffuse signal power in each sub-channel $\xi$ is set to 6 for combined Rayleigh/Ricean fading channel. In conclusion, it is shown that the saturation throughput is always less than the maximum throughput at all the payload size and the higher the transmission rate be, the higher the decreasing rate of saturation throughput compared to the maximum throughput be.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.229-234
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• 1999

We analyzed the reliability characteristics in platinum schottky diodes with variations of n-type silicon substrates concentrations and temperature variations of measurements. The parameters of reliability measurement analysis are saturation current. turn-on voltage and ideality factor in the forward bias, the breakdown voltage in the reverse bias with device shapes. The shape of devices are square type and long rectangular type for edge effect. As a result, we analyzed that the forward turn-on voltage, barrier height, dynamic resistance and reverse breakdown voltage were decreased but ideality factor and saturation current were increased by increased concentration in platinum and n-silicon junction parts. In measurement temperature(RT, $50^{\circ}C$, $75^{\circ}C$), the extracted electrical parameter values of reliability characteristics were increased at the higher temperature under the forward and reverse bias. The long rectangular type devices were more decreased than the square type in reverse breakdown voltage by tunneling effects of edge part.

• 전기의세계
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• v.19 no.4
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• pp.12-17
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• 1970

BaO.nFe$_{2}$O$_{3}$ Powder ferrite magnet was made by sintering process. The purity of the powder were 99.6% far BaO. 99.5% for Fe$_{2}$O$_{3}$, and the grain size 1-3 micron. The Optimum mixing ratio n=4.4 the optimum density 4.8gr/cm$^{3}$ and the optimum second sintering temperature 1260.deg. C was found. The theoretical bloch wall, dimension of domain and energy per unit volume of BaFe$_{12}$O$_{19}$ were compared with pure Fe. Also, the saturation magnetization and maximum energy product were computed.d.d.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.457-460
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• 1998

단 채널 MOSFET 소자의 드레인 전압-드레인 전류 특성을 예측하기 위해서 caughey-thomas 이동도 모델을 수치적으로 구현하는 방법을 제안한다. 구현된 caughey-thomas 모델의 정확한 특성을 검증하기 위해서 0.5[.mu.m]의 설계규칙을 가즌 ASIC용 공정으로 n-MOSFET과 p-MOSFET을 제작하였다. 전자 및 정공의 포화속도 값이 각각 6.2*10/sup 6/[cm/sec] 과 1.034*10/sup 7/[cm/sec]인 경우에 채널길이가 0.5[.mu.m] 이상인 n-MOSFET과 p-MOSFET의 드레인 전압-드레인 전류특성의 모의실험 결과는 측정값에 비하여 10% 이내의 상대오차를 보였다.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.14-15
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• 2002

Iron nitride alloy films prepared in the form of laminated ${(Fe_{97}Al_3)}_{85}N_{15}/Al_2O_3$ multilayers (Ml's) due to excellent soft magnetic properties and high saturation magnetization [1, 2] are very promising materials for poles and shields in ultra high density thin film heads. The present work concerns the ferromagnetic (FM) coupling effect as a function of the thickness of $Al_2O_3$ spacers by analysis of the magnetic domain structure.

• Journal of the Korean Magnetics Society
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• v.13 no.1
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• pp.6-14
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• 2003

The purpose of this study is to investigate the effect of chemical reaction with a bonding glass on physical and magnetic properties of Fe-Hf-N/SiO$_2$ and Fe-Hf-N/Cr/SiO$_2$ thin films. When the Fe-Hf-N/SiO$_2$ films were reacted with the bonding glass, the soft magnetic properties of them were extremely degraded. At $600^{\circ}C$, the saturation magnetization of the reacted film decreased to 1 kG, and its coercivity increased to 27 Oe, and its effective permeability decreased to 70. It was found that the degradation of soft magnetic properties of the Fe-Hf-N/SiO$_2$ films reacted with the bonding glass were attributed to the oxidation of the Fe-Hf-N layers to HfO$_2$ and Fe$_3$O$_4$. The soft magnetic properties of the Fe-Hf-N/Cr/SiO$_2$ films reacted with the bonding glass were degraded less than those of Fe-Hf-N/SiO$_2$ films. At $600^{\circ}C$, the saturation magnetization of the reacted film decreased to 13.5 kG, and its coercivity increased to 4 Oe, and its effective permeability decreased to 700. It was found that the Cr layer suppressed the oxidation of the Fe-Hf-N layers during the chemical reaction between the Fe-Hf-N layer and bonding glass.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.93-94
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• 2007

• Journal of the Korean Magnetic Resonance Society
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• v.6 no.2
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• pp.94-102
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• 2002

An interesting recent application of intermolecular NOE experiment is the saturation transfer difference NMR(STD-NMR) method that is useful in screening compound libraries to identify bio-active ligands. This technique also identifies the group epitopes of the bound ligand in a reversibly forming protein-ligand complex. We present here a complete relaxation and conformational exchange matrix (CORCEMA) theory (Moseley et al., J. Magn. Reson. B, 108, 243-261 (1995)) applicable for the STD-NMR experiment. Using some ideal model systems we have analyzed the factors that influence the STD intensity changes in the ligand proton NMR spectrum when the resonances from some protons on the receptor protein are saturated. These factors will be discussed and some examples of its application in some model systems will be presented. This CORCEMA theory for STD-NMR and the associated algorithm are useful in a quantitative interpretation of the STD-NMR effects, and are likely to be useful in structure-based drug design efforts. They are also useful in a quantitative characterization of protein-protein (or protein-nucleic acid) contact surfaces from an intermolecular cross-saturation NMR experiment.