원형도파관과 구형도파관간의 T-접합 분기회로 해석

문성익,김윤영,허광삼,양두영 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.1

In this paper, the T-junction branch network of the orthomode transducer is analyzed. The T-junction branch network consists of the cylindrical comnion waveguide and the rectangular sub-waveguide. Using the vector potential of each region. the hybrid mode is considered Based on the derived electromagnetic components. scattering parameters of the T-junction branch network are calculated. The cylindrical waveguide size and the rectangular waveguide size are WR62 and WC55. In order to analyze the discontinuity of the T-junction branch network. high order mode of the branch region is considered the 15th. From the results. the transmission coefficient. S_(31) and S_(21) show -3dB. the reflection coefficient. S_(11) and S_(33) are -10dB. -8dB in the range of 13.3GHz-16GHz.

제1형 당뇨병 환자에서 췌도세포 동종이식의 반복시행

양태영,정인경,서인아,오은영,조건영,오승훈,김성주,정재훈,민용기,이명식,이문규,김광원,도영수,주성욱 대한당뇨병학회 2002 Diabetes and Metabolism Journal Vol.24 No.4

연구배경:췌도세포 이식은 시술이 간편하고 안전하기 때문에 반복이식이 가능하여 그 동안 여러 센터에서 반복이식의 성공을 보고한 바 있다. 국내에서도 본 병원을 비롯하여 몇몇 센터에서 췌도세포 이식이 활발히 시도되고 있으나 사람에서의 동종이식 및 동종 이식의 반복시행은 보고된 바 없는 실정이다. 저자 등은 국내 최초로 췌도세포 동종이식을 시행하여, 혈청 C­펩타이드가 증가하고 인슐린 요구량이 감소하였으며, 혈당농도와 당화혈색소의 안정을 보였다. 그러나 이식 70일 후 다시 인슐린 요구량이 증가하고 C­펩타이드가 감소하여 췌도세포 이식을 다시 시행한 바 있다. 2차 이식 후 70여일이 지난 현재 다시 혈청 C­펩타이드가 증가하고, 인슐린 요구량이 더 감소되어 췌도세포 이식에서 반복 시행의 유용성을 보고하는 바이다. 방법:환자는 32세 남자로 17년전 당뇨병 진단 후 인슐린 치료 중이었으며, 3년전 부터는 만성신부전증으로 혈액툭석을 하고있었다. 1999년 12월 25일 신장이식을 하였고 3일 후 췌도이식을 하였으며, 두번째 이식은 70일 후 시행하였다. 췌도분리는 변형된 Recordi방법과 비연속성 자당 농도차(discontinuous density gradient)를 이용하였으며 분리한 췌도는 배양 후 환자의 신장기능이 정상화되고 미생물학 검사에서 음성을 확인한 후 경피경간으로 간문맥을 접근하여 16G 폴리 에틸렌 카테터를 이용하여 간실질에 이식하였다. 결과:1차 췌도이식시 순수분리전 췌도수는 210,000개, 순수분리후 획득한 췌도수는 90,000개, 순도 95%, 세포양 1.0mL 이었고, 2차 췌도이식시 순수분리전 췌도수는 420,000개, 순수분리후 획득한 췌도수는 370,000개, 순도 95%, 세포양 1.5mL 이었다. 1,2차 모두 간문맥을 통해 약 20분에 걸쳐 간실질에 주입하였다. 췌도이식전 인슐린요구량은 75∼75U/일, HbA1e 8∼10%, C­펩타이드 0.6ng/mL 였으며, 1차 췌도이식수 7일째 인슐린 요구량은 40U/일, C­펩타이드 1.5ng/mL, FPS 109mg/mL 였고, 40일 추적관찰 후 인슐린 요구량이 36U/일, C­펩타이드 1.8ng/mL, HbA1e 6.5∼7.0%로 안정되었다. 그러나 이식 50일째부터 인슐린 요구량이 50∼56U/일, C­펩타이드 0.6ng/mL, FPS 130∼200mg/dL로 혈당 조절이 불안정하여 다시 췌도이식을 시행하였다. 2차 이식후 50일이 경과한 현재, 인슐린 요구량은 26U/일, C­펩타이드 1.8ng/mL, FPS 90∼120mg/dL로 다시 안정되었다. 결론:췌도이식은 반복이식이 가능하며, 본 환자의 경우 인슐린요구량 감소, 혈당의 안정화 및 C­펩타이드가 상승하여 이식한 췌도의 기능을 확인할 수 있었고, 향후 스테로이드 등 면역억제가 유지 용량으로 감량되면 인슐린 요구량은 더 감소될 것으로 기대된다. Over the past 20 years, significant advances have been made in human islet transplantation. However, cases of prolonged insulin independence after islet allotransplantation have rarely been reported and over time, a slight, gradual decrease in insulin secretion appears to occur, as suggested by the lower C-peptide. Although preliminary clinical success achieved over the past few years has been considerably higher with whole pancreatic transplant than with isolated islet grafts, both approaches remain experimental. Islet grafts might gain, over time, increasing credibility and might eventually provide an easier alternative in terms of grafting procedures and patient management, as compared with the more "traumatizing" whole-pancreas transplantation. Also, using islet, re-transplantation is possible. But it is not known whether re-transplantation of islet could be suitable for those patients who lost grafted islet function. The aim of the present study was to investigate the benefits of re-transplantation of islet in previously simultaneous islets-kidney transplant (SIK) patient who have lost graft function. Methods : The recipient was a 32 year old male. First islet transplantation was underwent at December 25, 1999. However, the grafted islets lost function after 70 days. So we performed re-transplantation of islets. The isolation of islet was conducted sterilely on a laminarflow hood and isolated by a modified Recordimethod. The islet was injected slowly into the liver via a cannular placed in the potalvein for 20 minutes. Results : Transplanted islets were 90,000 IEq at first islet transplantation, 370,000 IEq at second islet transplantation. The insulin requirement was reduced from 75-85 to 35-40 U/day, the basal C-peptide level was 1.5 ng/mL at 7 days posttransplant Unfortunately, the grafted islets lost function after 70 days. After second transplantation, the insulin requirement was reduced to 26 U/day. Conclusions : Despite the continuous need for exogenous insulin therapy, islet transplantation can prevent wide glucose fluctuations, thus resulting in normalization of glycemic control and improvement in HbAlc, and also, show that islets can be successfully and safely re-transplanted intraportally in patients who have lost previously grafted islet function (J Kor Diabetes Asso 457~466, 2000).

전치왜곡방식을 이용한 선형 전력증폭기 설계

허광삼,문성익,양두영 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.2

This paper deals with designing the linear power amplifier using MESFET and Schottky diode. The power amplifier is designed to be ensure 3-W linear output using MESFET, and made up of 3-stage class-AB amplifiers in cascade. By choosing the final stage as the balanced structure, the output linearity is enhanced. The balanced structure of amplifier is composed of the Wilkinson power divider and combiner. In the designed 3-stage amplifier, when the input power is lower than -5dBm, power gain is 38dB. And it rapidly decreases as the input power increases larger than -5dBm. Therefore, to compensate for decreasing the gain, pre-distorter circuit is inserted in front of 3-stage amplifier. The pre-distorter is implemented using parallel Schottky diode. The optimized linear power amplifier is composed of these pre-distorter and 3-stage power amplifier. As a result, when the maximum input power is 9dBm, the 1-dB gain compression point of linear power amplifier, P1dB, is 37.61dBm

MUSIC 알고리즘을 이용한 적응 빔 성형에 관한 연구

문성익,이광식,양두영 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.1

In order to estimate DOA(Direction Of Arrival) of signal, the adaptive beam forming algorithm based on MUSIC(Multiple Signal Classification) is studied and analyzed. The eigenvalues for the signal component and the noise component are obtained from correlation matrix of the received signal by array antenna. The eigenvalues classified the signal components into the noise components decide the power spectrum of the received signal. From the results, DOA is estimated by the signal and noise spatial vector, and the steering beam pattern is found by weight vectors calculated from the spatial vector, effectively.

원형도파관과 구형도파관간의 T-접합 분기회로 해석

문성익,허광삼,김윤영,양두영 제주대학교 산업기술연구소 2000 尖端技術硏究所論文集 Vol.11 No.1

In this paper, the T-junction branch network of the orthomode transducer is analyzed. The T-junction blanch network consists of the cylindrical common waveguide and the rectangular sub-waveguide. Using the vector potential of each region, the hybrid mode is considered. Based on the derived electromagnetic components, scattering parameters of the T-junction branch network are calculated. The cylindrical waveguide size and the rectangular waveguide size are WR62 and WC55. In order to analyze the discontinuity of the T-junction branch network, high order mode of the branch region is considered the 15th. From the results, the transmission coefficient. S31 and S21 show -3dB, the reflection coefficient, S11 and S33 are -10dB, -8dB in the range of 13.3GMz∼16GHz.

가상상점 활용의 영향 요인에 관한 연구

양광민,문병관 中央大學校 經營硏究所 1999 經營學論集 Vol.25 No.2

IMT-2000 중계기용 전력증폭기 설계

허광삼,문성익,김흥수,양두영 濟州大學校 産業技術硏究所 2001 산업기술연구소논문집 Vol.12 No.1

This paper deals with designing the mobile station power amplifier of IMT-2000 using analog predistortion method. The power amplifier made up of 3-stage class-AB amplifiers in cascade. By choosing the final stage as the balanced structure. the output linearity is enhanced. The balanced structure of amplifier is composed of the Wilkinson power divider and combiner. Therefore. to compensate for the linearity of the power amplifier. pre-distorter circuit is inserted in front of 3-stage amplifier. The pre-distorter is implemented using parallel Schotty diode. The optimized linear power amplifier is cornposed of these pre-distorter and 3-stage power amplifier.

임신마우스에서 수용성카이토산에 의한 태아의 방사성스트론튬 오염 억제

채기문,최근희,양광희,범희승,김지열,김광윤 대한방사선 방어학회 1994 방사선방어학회지 Vol.19 No.3

핵분열생성물중의 하나인 방사성스트론튬은 임신한 쥐에서 태반을 빠르게 통과하여 태아를 오염시킨다. 독성이 적은 천연착화제로서 마우스체내의 방사성스트론튬(Sr-85)의 제거에 효과적인 것으로 알려진 카이토산을 이용하여 Sr-85의 태반오염억제에 관한 연구를 하였다. 실험군은 일반식이를 공급한 대조군과 임신 17일째에 수용성카이토산을 피하(1% 카이토산), 구강(10% 카이토산), 복강(0.3% 카이토산)으로 주사한 카이토산군으로 분류하였다. 피하주사군은 Sr-85 오염후 카이토산을 주사한 군이며 복강과 구강주사군은 Sr-85 오염젼 15일간 카이토산을 공급한 군이었다. 출산과 동시에 어린마우스의 전신을 측정한 겨러과 출생후 7일째에 대조군이 2.8 ±0.3%의 전신축적율을 나타낸 반면 피하, 구강, 복강, 주사군은 각각 1.2 ±0.1%, 1.4 ±0.1%, 1.6 ±0.2%로 나타났다. 결과적으로 임신한 마우스에서 수용성카이토산은 방사성스트론튬의 태반오염을 유의하게 억제하는 것으로 사료된다. Radiostrontium passes the placental barrier in pregnant rodents very well. Chitosan, a natural nontoxic chelator, was reported to reduce whole body retention of radiostrontium in mice. The aim of the present study was to evaluate water soluble chitosan as a blocking agent of transplacental transfer of radiostrontium in pregnant mice. Twenty pregnant mice wre divided into four groups : control and three groups of chitosan treatment(groups 1 to 3). Sr-85(15KBq in 0.2ml saline) was subcutaneously injected into pregnant mice at the 17th day of pregnancy. In control mice, 0.2ml saline was given 5 hours after the injection of Sr-85. In group 1.1% water soluble chitosan was given subcutanously for two days, twice daily after the injection of Sr-85. In group 2, 10% water soluble chitosan was given orally for 15 days before conception. In group 3, 0.3% water soluble chitosan was injected intravenously for 15 days, once daily before conception. Gamma counting of newborns were done at days 0, 2 and 7 after their births. Whole body retention of Sr-85 in newborns of control mice at days 0, 2, 7 were 3.1 ±0.3%, 2.9 ±0.3%, 2.8 ±0.3% respectively. In experimental groups, whole body retention of Sr-85 was significantly lower thanthat of control(p<0.01) and no statistical difference was noted between them. In group 1, the values were 2.1 ±0.3%, 1.4 ±0.1%, 1.4 ±0.1%, respectively. In group 3, they were 2.1 ± 0.2%, 1.7 ± 0.2%, 1.6 ± 0.2%, respectively. In conclusion, the water soluble chitosan reduced transplacental contamination of radiostrontium in pregnant mice.

전치왜곡방식을 이용한 선형 전력증폭기 설계

허광삼,문성익,양두영 濟州大學校 産業技術硏究所 2000 산업기술연구소논문집 Vol.11 No.2

This paper deals with designing the linear power amplifier using MESFET and Schottky diode. The power amplifier is designed to be ensure 3-W linear output using MESFET. and made up of 3stage class-AB amplifiers in cascade. By choosing the final stage as the balanced structure. the output linearity is enhanced. The balanced structure of amplifier is composed of the Wilkinson power divider and combiner. In the designed 3-stage amplifier. when the input power is lower than -5dBm. power gain is 38dB. And it rapidly decreases as the input power increases larger than -5dBm. Therefore. to compensate for decreasing the gain. pre-distorter circuit is inserted in front of 3stage amplifier. The pre-distorter is implemented using parallel Schottky diode. The optimized linear power amplifier is composed of these pre-distorter and 3-stage power amplifier. As a result. when the maximum input power is 9dBm. the 1-dB gain compression point of linear power amplifier. P_(ldB). is 37.61dBm

IMT-2000 중계기용 전력증폭기 설계

허광삼,문성익,김홍수,양두영 제주대학교 산업기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.1

This paper deals with designing the mobile station power amplifier of IMT-2000 using analog predistortion method. The power amplifler made up of 3-stage class-AB amplifiers in cascade. By choosing the final stage as the balanced structure, the output linearity is enhanced. The balanced structure of amplifier is composed of the Wilkinson power divider and combiner. Therefore, to compensate for the linearity of the power amplifier, pre-distorter circuit is inserted in front of 3-stage amplifier. The pre-distorter is implemented using parallel Schotty diode. The optimized linear power amplifier is composed of these pre-distorter and 3-stage power amplifier.