• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.1-6
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• 1998

The dielectric effects of plastic packages on GaAs($\varepsilon$$_{r}$=13) MMIC microstrip characteristics are analyzed using the spectral domain method (SDM). As being packaged by typical FR-4 composites ($\varepsilon$$_{r}$=14.2) for PCB substrates and plastic packages, the characteristic impedance is reduced by about 6 %, but the effective dielectric constant is increased by 13 % from those of bare microstrip, respectively. The parasitic effects of the packaging materials can greatly degrade the performance of the packaged MMIC. We also calculated the optimum microstrip width, which maintains the 50 $\Omega$ matching condition after plastic packaging. These calculated results can be used to optimize the plastic packages, and extend the application ranges for low cost MMIC production.n.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.12
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• pp.2205-2209
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• 2007

In this paper, a voltage controlled oscillator(VCO) of core components for wireless subscriber network is designed. The type of oscillator is colpits method and the oscillator device uses a LC resonator. The product is made on FR-4 substrate with dielectric constant of 4.6. The designed VCO is operated at 3.2V, 10mA and has output value of 0.67dB. The VCO's phase noise property is -102DBc/Hz at offset frequence of 100kHz. The fabricated VCO is the same as target value and can be used for wireless subscriber network.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1609_1610
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• 2009

LED는 광학특성을 유지하기 위해서 최적의 방열설계가 요구된다. 이 논문에서는 입력FR-4의 Top Layer의 면적을 506.25[$mm^2$]이상으로 확대함으로써, 인가 전력 0.5W 조건하에서 FR-4 PCB로 MCPCB와 유사한 방열 특성을 발휘할 수 있음을 열화상카메라를 통한 측정 및 전산모사를 이용하여 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.2064-2070
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• 1995

Characteristics of thermal flow stratification were studied experimentally by using the small scale pressurizer-surge line model. Thermal flow stratifications in the horizontal section of surge line were analyzed by the relation between the maximum temperature difference at any cross section in surge line and the Froude number representing the boundary conditions, i.e., in/out surge flow velocity and temperature difference of system. Thermal flow stratifications in outsurge flow decreased inversely proportional to the Froude number and did not exist for Fr>1. In insurge flow thermal flow stratifications disappeared near Fr=1.5, but resulted in the higher temperature difference than the case of outsurge flow.

• Water for future
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• v.20 no.3
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• pp.247-252
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• 1987

The negative buoyant flow into and through a regulating pond is analysed by numerical scheme. The controlling parameter of density current in the pond is found to be the inflow densimetric Froude number, $Fr_e$. Two vortices are formed and notable at the right corner and above the sunken flow in th pond. For given inflow characteristics, the required outflow temperature, the combination of dimensions of the pond and the residence time of the inflow in the pond are determined.

• The Korean Journal of Mycology
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• v.7 no.2
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• pp.87-90
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• 1979

Attempts were made to investigate sterol components of Schizophyllum commune Fr. which is one of medicinal fungi and grows wildly in Korea. Its carpophores were collected in Mountain Gwanak and extracted with chloroform and methanol. A sterol was isolated and identified as ergosterol by TLC, GLC and chemical tests.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1275-1279
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• 2012

In this paper, we design of dual-band microstrip antenna for wireless communication. We used IEEE 802.11a and Hyper LAN (5.725~5.825 GHz). The proposed antenna substrate is FR-4, size is $22mm{\times}23mm$, thickness is 1.6mm and used to CST Microwave Studio 2010 program. As a result the simulation has good result and good return loss below -10 dB at 5 GHz and 5.8 bandwidth.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5827-5831
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• 2011

In this paper, 5Ghz microstrip patch antenna for wireless LAN is designed, fabricated, and measured. To obtain wide bandwidth and high gain, antenna parameters such as patch size(W, L), the length of the slot(C), and the slot width(D) are simulated by HFSS(High Frequency Structure Simulator). From these parameters optimized, the microstrip patch antenna is fabricated using FR-4 substrate. The measured results of the antenna are as follows: The center frequency of 5.2 GHz, insertion loss of -41.17dB, bandwidth of 258MHz, and VWSR of 1.1.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10a
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• pp.301-304
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• 2006

디바이스 드라이버는 커널 고장을 유발하는 가장 큰 원인이며, 커널 영역에서 동작하므로 커널에 큰 영향을 미칠 수 있다. 본 논문은 운영체제의 신뢰성을 향상시키기 위하여, 디바이스 드라이버 실패가 발생했을 때, 고장난 드라이버와 이 드라이버를 사용하는 응용 프로그램을 복구하는 방법을 제시한다. 우리는 논문에서 제시한 복구 시스템을 FRS (Failure Recovery Subsystem) 이라고 부르겠다. 디바이스 드라이버가 고장 났을 때, FRS는 디바이스 드라이버의 실행 환경을 다양하게 변경하고 드라이버를 재실행함으로써 같은 고장이 반복되지 않도록 한다. FRS은 고장을 복구하고 디바이스 드라이버를 정상적으로 실행함으로써 전체 시스템의 안정성을 향상시킨다.

• Childhood Kidney Diseases
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• v.3 no.1
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• pp.48-56
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• 1999

Purpose : This multicenter collaboratory study was conducted to see the therapeutic efficacy and side effect of cyclosporine A (Cipol-$N^{(R)}$, Chong Kun Dang) on children with idiopathic nephrotic syndrome who experienced frequently relapsing (FR), steroid dependent (SD), or steroid resistant (SR) pattern. Patients and methods : Thirty-nine children with SD/FR NS and 3 children with SR NS were enrolled in the study. After induction of remission (SD/FR NS) with steroid or after 4 weeks of steroid therapy (SR NS), cyclosporine A was started in a dose of 4-5 mg/Kg/day in two divided dose and steroid (prednisolone or equivalent dose of deflazacort) was tapered slowly. During 16 weeks of study period, monthly check up of physical examination and various laboratory tests including BUN, creatinine, Ccr and cyclosporine blood level were done. Results : Out of 39 children with SD/FR NS, 35($89.7\%$) maintained sustained remission and at 4 weeks after therapy, values of serum protein, albumin, cholesterol, and 24 hours urinary protein excretion showed normal values. Two out of 3 children with SR NS showed and sustained remission with cyclosporine A therapy. Side reaction to cyclosporine A therapy showed hypertrichosis in 8 cases and hyperuricemia in 5 cases. However, other laboratory tests including CBC, liver profile, BUN, creatinine and GFR (creatinine clearance utilizing 24 hour urine) did not show any abnormalities during the 16 weeks of study period. Conclusion : Cyclosporine A (Cipoi-$N^{(R)}$ Chong Kun Dang) can be utilized quite effectively on children with SD/FR or SR NS and further trial of cyclosporine A on long-term basis (1-2 year period) is needed to determine it's efficacy and side effect (especially nephrotoxicity) of long-term administration of cyclosporine A.