• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.415-418
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• 2007

This paper presents the design and analysis of LNA-Mixer for 2.45GHz RFID reader. The LNA is implemented by PCSNIM method for low power consumption. The Mixer is implemented by using the Gilbert-type configuration, current bleeding technique, and the resonating technique for the tail capacitance. The connection between the two designed circuits is made by active balun. This LNA-Mixer has about 35dB for -40dBm input RF power, LO power is 0dBm and RF frequency is 2.45 GHz and IIP3 is -4dBm. The layout of LNA-Mixer for one-chip design in a $0.18-{\mu}m$ TSMC process has 2.6mm ${\times}$ 1.3mm size.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.213-218
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• 2005

The purpose of this study is the characteristics of an innovative inlet system with shock/boundary layer interactions by using various types of bumps which are substituted for the conventional bleeding system in supersonic inlet. This study performs a comprehensive numerical effort that be directed at better understanding the three-dimensional flowfield includes shock/boundary layer interaction and growth of turbulent boundary layer that occur around a three-dimensional bump in a supersonic inlet. The characteristics of boundary layer seen in the current numerical simulations indicates the potential capability of the three-dimensional bump to control shock/boundary layer interaction in supersonic inlets.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.11
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• pp.1982-1987
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• 2007

This paper presents the design and analysis of LNA-Mixer for 2.45GHz RFID reader. The LNA is implemented by PCSNIM method for low power consumption. The Mixer is implemented by using the Gilbert-type configuration, current bleeding technique and the resonating technique for the tail capacitance. The connection between the two designed circuits is made by active balun. This LNA-Mixer has about 22dB gain and 8.5dB Noise Figure for -50dBm input RF power, LO power is 0dBm, RF frequency is 2.45 GHz and IF frequency is 100kHz. The layout of LNA-Mixer for one-chip design in a 0.18-um TSMC process has $2.5mm{\times}1.0mm$ size.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1508-1509
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• 2007

본 논문에서는 TSMC 0.18um공정을 이용한 무선통신 수신기용 직접변환 방식의 Double Balanced Mixer를 설계 하였다. 제안된 mixer는 current bleeding기법과 내부에 인덕터를 추가하여 기존의 Gilbert Cell구조의 mixer에 비해 변환 이득과 Flicker Noise특성을 향상 시켰다. 모의실험결과 2.45GHz에서 11dB의 변환이득을 나타내었으며 Flicker Noise의 corner frequency는 510kHz이고 이때 잡음특성은 10.8dB이다. 이 회로의 동작전압은 1.8V이며 소모 전력은 8.8mW이다.

• Journal of Chest Surgery
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• v.16 no.3
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• pp.322-330
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• 1983

TAPVC represents 1 to 4% of all congenital cardiac defects. Generally severe and refractory cardiac failure develops in the majority of patients in the early infancy. In a small minority of patient, they are relatively asymptomatic in infancy, but symptoms will develop of necessity In the later life. Our three cases had dyspnea on exertion and cyanosis and had a history of frequent respiratory infections. All 3 cases had the typical showman configuration on roentgenograms of the chest. Current surgical therapy has greatly altered the unfavorable course of these patients after institution of extra-corporeal circulation. We have experienced three cases from June, 1973 to May, 1983, the patients were undergone complete repair with extracorporeal circulation at the Department of Thoracic and Cardiovascular Surgery in the Yonsei University. The ages ranged from 12 years to 14 years, all cases were supracardiac type of TAPVC. Only one case died due to bleeding from anastomosis site between LA and pulmonary venous trunk. In the remaining two patients with complete corrections of TAPVC, there was excellent relief of symptoms such as dyspnea and cyanosis. Their postoperative course have been good during follow-up.

• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.27-34
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• 1999

The goal of oral anticoagulation therapy with warfarin is to maintain INR values within the therapeutic range in order to prevent complications such as bleeding and thrombosis. The purposes of this study were to investigate the current level of anticoagulation control using INR values, to investigate the incidences of thromboembolism and bleeding complications, and to compare the effect of low intensity INR regimen with therapeutic range recommended by ACCP (American College of Chest Physician). Two hundred three patients with mechanical heart valve replacement done at Yonsei University Cardiovascular Center between January 1994 and December 1996 were selected and reviewed retrospectively. The target INR ranges of $2.5\sim3.5$ (ACCP standard) and low intensity INR of $2.0\sim3.5$ were used for evaluation. According to ACCP standard, $51.2\%$ of patients and $31.1\%$ of INR values were within the therapeutic range when average INR and cumulative INR were used, respectively. Applying low intensity INR values of $2.0\sim3.5$, the therapeutic control was achieved in $57.4\%\;and\;90.1\%$, using average INR and total INR, respectively. The incidences of major and minor bleedings were $0.5\%\;and\;26.6\%$, respectively. The incidence of thromboembolism was $0.5\%$. There was no significant difference in terms of complication incidences between INR $2.0\sim2.5\;and\;INR\;2.5\sim3.5$ groups. However, INR values at the time of bleeding were generally high. In conclusion, the evaluation of patients with mechanical heart valve replacement showed low level of therapeutic control with warfarin therapy. This is partially explained by the fact that the physicians at Yonsei University Cardiovascular Center were using lower intensity INR values as a goal than recommended INR. Also, in the near future, systematic anticoagulation service should be implemented at various hospitals in Korea so that patients on anticoagulant therapy can be more closely monitored to be within the recommended INR by ACCP.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.419-426
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• 2010

This paper discusses a series of experiments including material improvement in order to ensure quality of grouting for the post-tensioned structure. In presstressed concrete, grouting refers to the construction procedure of filling empty space of duct enclosing the prestress tendons using cementitious material, To date, adequate quality control of the grouting has not been established in Korea because the relationship between the grouting and durability of post-tensioned structure is not well-recognized. The Korean standard does not consider the important material characteristic, wick effect, which is caused by tendons in the ducts, and furthermore current standard testing method does not quantify reasonable material segregation. As a result, the grout material, which satisfies the current material standards, may well exhibit excessive bleeding of water or shrinkage during construction. In this study, international codes and standards related to grouting were surveyed. The mix proportions of the constituents and novel admixtures were suggested to meet equivalently with these standards. Performance of this enhanced grout was compared with common domestic grouts using the international standard testing method. A series of mock-up specimens considering geometry of PC beam was constructed and grout flow pattern was observed as the grout was injected. It was observed that the grouting performance was highly influenced by material properties and filling characteristic can be varied depending on geometry of ducts.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.443-451
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• 2010

This paper describes a fully integrated CMOS low-IF mobile-TV RF tuner for Band-III T-DMB/DAB applications. All functional blocks such as low noise amplifier, mixers, variable gain amplifiers, channel filter, phase locked loop, voltage controlled oscillator and PLL loop filter are integrated. The gain of LNA can be controlled from -10 dB to +15 dB with 4-step resolutions. This provides a high signal-to-noise ratio and high linearity performance at a certain power level of RF input because LNA has a small gain variance. For further improving the linearity and noise performance we have proposed the RF VGA exploiting Schmoock's technique and the mixer with current bleeding, which injects directly the charges to the transconductance stage. The chip is fabricated in a 0.18 um mixed signal CMOS process. The measured gain range of the receiver is -25~+88 dB, the overall noise figure(NF) is 4.02~5.13 dB over the whole T-DMB band of 174~240 MHz, and the measured IIP3 is +2.3 dBm at low gain mode. The tuner rejects the image signal over maximum 63.4 dB. The power consumption is 54 mW at 1.8 V supply voltage. The chip area is $3.0{\times}2.5mm^2$.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.271-275
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• 1976

Truncus arteriosus is a rare and highly lethal cardiac anomaly characterized by a single arterial trunk emerging from the heart and supplying the coronary, systemic, and pulmonary circulations, The first successful correction of truncus arteriosus was reported by McGoon et al. in 1968 and was based on experimental work reported by Rastelli et al. in 1967 in which a conduit consisting of a homograft of the ascending aorta and aortic valve was used to establish continuity between the right ventricle and the pulmonary arteries, Modification of this procedure using a Dacron tube valved with porcine xenograft instead of a homograft have resulted in the current definite treatment for truncus arteriosus. This report describes an 3 years and 4 months old boy with heart failure from type I truncus arteriosus who was diagnosed as the V. S. D. with pulmonary hypertension preoperatively and underwent corrective surgery employing the Rastelli procedure using a Dacron conduit valved with canine xenograft, but died due to massive bleeding from the anastomosis sites in operating room.

• Journal of Chest Surgery
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• v.24 no.2
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• pp.143-152
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• 1991

From 1983, until June, 1990, 10 patients with various type of truncus arteriosus underwent total surgical correction including Rastelli procedure at Seoul National University Hospital. The age at operation ranged from 1 month to 9 years [mean 2.1 years]. Six patients had truncus type I, 3 patients had truncus type II, and one patients had truncus type IIIc. Right ventricular pulmonary artery continuity was established with a porcine valved conduit in 6 patients, mechanical valved conduit in 1 patient, and bovine pericardial conduit in 3 patients. The postoperative right ventricular /left ventricular pressure ratio ranged from 0.4 to 0.71 [mean 0.51${\pm}$0.14]. The lung histology revealed grade II pulmonary obstructive disease even at 4 month of age. Five patients were dead in hospital [50%], and they were less than 2 year of age. One patient, who had severs congestive heart failure preoperatively, died of low output syndrome and the other died of low output syndrome with postoperative bleeding. There were three death, because of a pulmonary hypertensive crisis that might have been prevented. Two of the five survivors had conduit failure over a mean follow up of 42 months [range 1 to 78 months]. Obstructed conduit was removed and a new conduit constructed using the conduit bed as the posterior wall and the patch of bovine pericardium and Dacron as patch the roof of the conduit. One patient died of acute cardiac failure during the operation. Although results in infants less than 2 years old have not been good, current improvement of intra-and postoperative care suggested that prompt repair is indicated for infants with truncus arteriosus.