• Proceedings of the IEEK Conference
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
• /
• pp.189-192
• /
• 2001

We have studied fabrication processes that form asymmetric $\Gamma$-gate with a 0.1${\mu}{\textrm}{m}$ gate length in MMIC's(Monolithic Microwave Integrated Circuits). Asymmetric $\Gamma$-gate was fabricated using mixture of PMMA and MCB. Thus pseudomorphic high electron mobility transistor (PHEMT's) with 0.1${\mu}{\textrm}{m}$ gate length was fabricated via several steps such as mesa isolation, metalization, recess, passivation. PHEMT's has the -1.75 V of pinch-off voltage (Vp), 63 mA of drain saturation current(Idss and 363.6 mS/mm of maximum transconductance (Gm) in DC characteristics and current gain cut-off frequency of 106 GHz and maximum frequency of oscillation of 160 GHz in RF characteristics.

• Journal of the Chungcheong Mathematical Society
• /
• 제20권3호
• /
• pp.333-342
• /
• 2007

Suppose that ${\mu}$ is a finite positive Borel measure on the unit ball $B{\subset}C^n$. The boundary of B is the unit sphere $S=\{z:{\mid}z{\mid}=1\}$. Let ${\sigma}$ be the rotation-invariant measure on S such that ${\sigma}(S)=1$. In this paper, we will show that if $sup_{{\zeta}{\in}S}\;{\int}_{B}\;P(z,{\zeta})d{\mu}(z)$<${\infty}$ where $P(z,{\zeta})$ is the Poission-Szeg$\ddot{o}$ kernel for B, then ${\mu}$ is a Carleson measure. We will also show that if $sup_{{\zeta}{\in}S}\;{\int}_{B}\;P(z,{\zeta})d{\mu}(z)$<${\infty}$, then the operator T such that T(f) = P[f] is compact as a mapping from $L^p(\sigma)$ into $L^p(B,d{\mu})$.

• Journal of Bio-Environment Control
• /
• 제13권1호
• /
• pp.44-50
• /
• 2004

This experiment was conducted to investigate the effects of different levels of light intensity (100, 200, 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, and natural light) on the growth and the fruit quality of cucumber(Cucumis sativus cv. Hyakunari-3). The results of this experiment indicated that plant height and length of lateral shoots were decreased under low light condition, but it was not significantly different among treatments. Leaf area and root weight were lowest under low light intensity(100 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$), but no significant differences were noted between 200 and 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$. Photosynthesis rate was decreased with reduced light intensity and total chlorophyll contents, root activity and xylem sap were also decreased under low light intensity, but there was no significant difference between 200 and 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$. From the SEM observation the erosion of the guard cells and closed stomata in low light treatment were shown and the size of stoma were small also the stomatal aperture were decreased with reducing the light intensity. Chlorosis in leaves and aborted-liked fruits were appeared under low light condition and Ca and Mg uptake in leaves were decreased by shading in proportion to the decrease of light intensity. Fruit yields were decreased by 65% under 400 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, and by 80${\sim}$90% under 200 and 100 ${\mu}mol\;{\codt}\;m^{-2}\;{\cdot}\;s^{-1}$, compared to those under the natural light. This low intensity of light caused the sharp decrease in the early harvested yields within two weeks and the fruit yields of lateral shoots were greatly decreased.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• 제44권8호
• /
• pp.22-29
• /
• 2007

A 2.5Gb/s 2:1 multiplexer(MUX) IC using $0.18{\mu}m$ CMOS was designed and fabricated. Inductive peaking technology was used to improve the performance. On-chip micro spiral inductor was designed to maximize the inductive peaking effect without increasing the chip area much. The designed 4.7 nH micro-spiral inductor was $20\times20{\mu}m2$ in size. 2:1 MUX with and without micro spiral inductors were compared. The rise and fall time was improved more than 23% and 3% respectively using the micro spiral inductors for 1.25Gb/s signal. For 2.5 Gb/s signal, fall and rise time was improved 5.3% and 3.5% respectively. It consumed 61mW and voltage output swing was 1$180mV_{p-p}$ at 2.5Gb/s.

• Journal of Advanced Marine Engineering and Technology
• /
• 제21권4호
• /
• pp.387-392
• /
• 1997

This paper describes a combination surge generator for carrying out performance tests on the surge protection circuits of shipboard electrical systems. Pspice simulations were performed to decide the values of the parts required and to analyze the characteristics of the generator circuitry. The surge generator fabricated can produce four of the most common surge test waveforms : the O.5i/S/100kHz Ringwave, the 1.2/50$\mu$S voltage, the 8/20$\mu$S current, and the lO/lOOOi/S voltage wave¬forms specified in ANSI Std. C62. Source impedances of the surge generator are 12$\Omega$ in the O.5$\mu$S/100kHz mode, O.5$\Omega$ in the 1.2/50$\mu$S and 8/20$\mu$S mode, and 40$\Omega$in the l0/1000$\mu$S mode, and are determined by the ratio of the maxi¬mum open - circuit voltage to the maximum short - circuit current. Experimental results show that the surge generator provides most of the outputs required for the testing of the surge protection circuits on shipboard electrical systems.

• Journal of IKEEE
• /
• 제17권1호
• /
• pp.71-76
• /
• 2013

AlGaN/GaN HEMTs (High electron mobility transistors) with narrow channel were fabricated and the effect of channel scaling on the device were investigated. The devices were fabricated using e-beam lithography to have same channel length of $1{\mu}m$ and various channel width from 0.5 to $9{\mu}m$. The sheet resistance of the channel was increased corresponding to the decrease of channel width and the increase was larger at the width of sub-${\mu}m$. The threshold voltage of the HEMT with $1.6{\mu}m$ and $9{\mu}m$ channel width was -2.85 V. The transistor showed a variation of 50 mV at the width of $0.9{\mu}m$ and the variation 350 mV at $0.5{\mu}m$. The transconductance of 250 mS/mm was decreased to 150 mS/mm corresponding to the decrease of channel width. Also, the gate leakage current of the HEMT decreased with channel width. But the degree of was reduced at the width of sub-${\mu}m$. It was thought that the variation of the electrical characteristics of the HEMT corresponding to the channel width came from the reduced Piezoelectric field of the AlGaN/GaN structure by the strain relief.

• Journal of Pharmacopuncture
• /
• 제10권2호통권23호
• /
• pp.19-23
• /
• 2007

Objectives : This experimental study was performed to investigate the continuous anti-bacterial potency of Sean-tang on cultivation of Staphylococcus species(S. aureus, S. epidermidis) that induce eye disease. Methods : Minimal inhibitory concentration(MIC) was measured by dropping to 50${\mu}$l diluted Sean-tang(100%, 10%,1%, 0.1%) on S. aureus, S. epidermidis that were cultivated from 2 to 6 days. 1. Anti-bacterial potency was measured by the size of inhibition zone with change of volume(20${\mu}$l, 30${\mu}$l, 40${\mu}$l, 50${\mu}$l). Results : 1. Anti-bacterial potency of Sean-tang on S. aureus was appeared in 100% and increased on 6 days. Anti-bacterial potency with change of volume was increased in propotion to increase volume. Anti-bacterial potency of Sean-tang on S. aureus was appeared continuous. 2. Anti-bacterial potency of S. epidermidis was appeared in 100%, 10%, 1% on 2 days and in100%, 10% on 6 days. In 100% Sean-tang, Anti-bacterial potency of 6 days was increased, in 10%, 1%, Anti-bacterial potency of 2 days was increased. Anti-bacterial potency with change of volume was increased inpropotion to increase volume and increased on 6 days, but bacteria was increased. Anti-bacterial potency Sean-tang on S. epidermidis wasn't appeared continuous. Conclusions : Anti-bacterial potency of Sean-tang on cultivation of S. aureus was showed continuous, but on cultivation of S. epidermidis was not showed continuous.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• 제37권12호
• /
• pp.1-9
• /
• 2000

A new method, the external resistance method (ERM method), is proposed for accurate extraction of the gate bias-dependent effective channel carrier mobility (${\mu}_{eff}$) and separated parasitic source/drain resistances ($R_S$ and $R_D$) of n-channel MOSFET's. The proposed ERM method is applied to n-channel LDD MOSFETs with two different gate lengths ($W_m/L_m=30{\mu}m/0.6{\mu}m,\;30{\mu}m/1{\mu}m$) in the linear mode of current-voltage characteristics ($I_D-V_{GS},\;V_{DS}$). We also considered gate voltage dependence of separated $R_2$ and $R_D$ in the accurate modeling and extraction of effective channel carrier mobility. Good agreement of experimental data is observed in submicron n-channel LDD MOSFETs. Combining with capacitance-voltage characteristics, the ERM method is expected to be very useful for accurate and efficient extraction of ${\mu}_{eff},\;R_D,\;R_S$, and other characteristic parameters in both symmetric and asymmetric structure MOSFET's in which parasitic resistances are critical to the improvement of high speed performance and reliability.

• Korean Journal of Food Science and Technology
• /
• 제41권6호
• /
• pp.694-699
• /
• 2009

The antimutagenic activities of ethanol extracts of Korean and American propolis were tested using Salmonella Typhimurium TA98 with two indirect mutagens of 3-amino-1,4-dimethyl-5H-pyrido [4,3-b]indole (Trp-P-1) and 2-aminoanthracene (2-AA) with S9 mix. Additionally, their antimicrobial activities against acne-related pathogenic strains of Propionibacterium acnes, Staphylococcus Epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using both paper disk method and agar dilution method. Ethanol extracts of Korean and American propolis showed strong inhibitory effects, in a dose dependant manner, against the mutagenicities induced by Trp-P-1 and 2-AA. The antimutagenic effect of ethanol extracts of Korean propolis showed significantly higher protective activity than that of American propolis against the Trp-P-1 induced mutagenicity of S. Typhimurium TA98 at the lower concentration ($1-10\;{\mu}g$), but significantly lower protective activity at the higher concentration ($50-200\;{\mu}g$). The antimutagenic effect of ethanol extract of Korean propolis showed significantly higher protective activity than that of American propolis against the 2-AA induced mutagenicity at the concentration of $1\;{\mu}g$, but significantly lower protective activity than that of the American at the higher concentration ($50-200\;{\mu}g$). Both extracts showed strong antimicrobial activities against all the acne-related pathogens tested, with minimal inhibitory concentration (MIC) values in the range $1,500-5,000\;{\mu}g/mL$.

• Proceedings of the KSAR Conference
• /
• 한국동물번식학회 2001년도 춘계학술발표대회
• /
• pp.67-67
• /
• 2001

전기자극은 핵이식 시 수핵난자와 공여핵의 융합을 위해 보편적으로 사용되는 방법이다(Robl, 1999). 그러나 부적절한 전기자극은 수핵난자 세포질에 해를 입히고, 이후의 배발달에 좋지 않은 영향을 준다. 본 실험은 체세포 핵이식을 \circled1 1.9㎸/cm, 20$\mu\textrm{s}$ 2회, \circled22.0㎸/cm, 20$\mu\textrm{s}$ 2회, \circled32.2㎸/cm, 10$\mu\textrm{s}$ 2회, 및 \circled41.9㎸/cm, 30$\mu\textrm{s}$ 2회의 전기자극으로 융합을 실시하여 각 자극 별 융합율과 난자의 lysis율을 비교하고, 배양 후 배반포 발생율을 조사하였다. 공여핵은 칡소의 귀 세포를 10% FBS가 첨가된 DMEM에서 39$^{\circ}C$, 5%$CO_2$의 incubator에서 배양하여 monolayer confluent형성 후 0.5% FBS가 첨가된 DMEM에서 3-4일간 배양 후 trypsin처리하여 제핵된 체외성숙 난자에 핵이식하였다. \circled1,\circled2,\circled3,\circled4의 핵이식 조건을 이용하여 공여핵의 체세포와 수핵란 세포질간의 융합을 유도한 결과, 융합율은 각각 50.7%, 48.1%, 65.5%, 및 33.3%였으며, 수핵난자의 세포질 lysis율은 39.%1, 41.7%, 22.6%,및 52.7%으로 \circled32.2㎸/cm, 10$\mu\textrm{s}$ 2회의 조건에서 융합율이 유의적으로 높았고, 수핵난자의 세포질 lysis율에 있어서도 다른 군에 비하여 낮았다 각각의 핵이식 조건별로 융합한 후 난할율 및 배반포 발생율은 각각 65.7%, 73.5%, 77.2%, 및 53.3%과 47.8%, 52.0%, 49.7%, 및 21.8%로 나타나 난할율 및 배반포 발생율에 있어서 융합조건에 따라 큰 차이는 없었으나 1.9㎸/cm, 30$\mu\textrm{s}$ 2회의 조건이 다른 조건들에 비하여 유의적으로 낮았다. 따라서, 체세포와 수핵란 세포질간의 융합율과 배반포 발생에 미치는 영향은 전압보다는 시간에 더 크게 받음을 알 수 있었으며, 이와 같은 결과에서 융합시 시간을 오래 주는 것보다 전압을 높이는 것이 수핵난자의 세포질에 상해를 줄이고 이후 배반포 발생에 유리할 것으로 사료되었다.