함정추적레이다용 Ku 대역의 고출력증폭기 제작

손형길(Hyung Kil Sohn),이춘성(Chunsung Lee),이건준(Kun-Joon Lee),정한경(Han Kyung Jung) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6

In this paper, a solid-state power amplifier (SSPA) was developed for ku-band tracking radar. The SSPA consists of a driving amplifier, a power divider, 16 unit power amplifiers, and a spatial power combiner. First, the main power amplifiers of 80W as components of the SSPA are designed and developed using GaN HEMT devices. Then, the output of a single SSPA is obtained by combining 16 main power amplifiers using a 16-way spatial power combiner. The developed SSPA shows an output of 60dBm in the Ku-band. This kind of SSPA can be applied to high-power applications of tracking radars, marine radar and multi-function radar, etc.

함정추적레이다용 Ku-대역 저손실 전력분배기 설계에 관한 연구

손형길(Hyung Kil Sohn),이춘성(Chunsung Lee),이건준(Kun-Joon Lee),정한경(Han Kyung Jung) 대한전자공학회 2023 대한전자공학회 학술대회 Vol.2023 No.6

YAZ를 이용한 Z39.50 서버의 설계 및 구현

손충범,송석일,최길성,조기형,유재수 충북대학교 컴퓨터 정보통신 연구소 1998 컴퓨터정보통신연구 Vol.6 No.1

전자도서관을 개발하는데 있어서 많은 핵심 기술들 중 하나가 바로 정보검색 프로토콜인 Z39.50이다. Z39.50 프로토콜은 시스템마다 다른 환경의 차이에서 생긴 정보검색상의 불편함을 해소하기 위해 제시되었다. 본 논문에서는 서로 다른 H/W 플랫폼 상에서 응용들간의 상호 운용성을 효과적으로 지원하기 위한 Z39.50 주요 서비스들의 인터페이스를 설계하고 구한다. 또한 사용 검색엔진인 Verity와 연동하여 하나의 완전한 정보검색 시스템을 구축한다. Information retrieval protocol Z39.50 is one of the most important technologies for digital libraries. Z39.50 protocol was presented in order to solve information retrieval protocol in the heterogeneous systems. In this paper we design and implement interfaces of Z39.50 main services that support effectively interoperability among applications on the heterogeneous H/W platform. Also we construct a complete information retrieval system by integrating the Z39.50 server and Verity search engine.

약물 중독 시 위 세척에 의한 산 - 염기 평형 및 전해질의 변화

윤형란(Hyung Ran Yun),손동현(Dong Hyun Sohn),이창범(Chang Bum Lee),이재웅(Jae Woong Lee),양석철(Suck Chul Yang),한동수(Dong Soo Han),손주현(Ju Hyun Sohn),김순길(Soon Kil Kim),김호중(Ho Jung Kim) 대한내과학회 1998 대한내과학회지 Vol.54 No.4

N/A Objectives: There is little information on the imbalance of electrolyte and acid-base metabolism associated with gastric lavage in acute drug intoxication patients. This study was aimed to analyze the acid-base and electrolyte abnormalities associated with gastric lavage in acute drug intoxication patients. Methods: We studied 24 acute drug intoxication patients who had performed gastric lavage with 10 liters of 0.9% NaC1. Electrolyte parameters and arterial blood gas analysis were carried out before and after gastric lavage. Results: After gastric lavage, acidosis was reduced in general. But there was no significant change in pH (7.34±0.02 vs. 7.38±0.15, p=NS). In acid-base balance, the mixed form of metabolic acidosis and respiratory acidosis was reduced from 7 to 2 cases, and the simple form of respiratory acidosis was reduced from 3 to 1 case. In contrast, normal form was increased from 5 to 7 cases and the simple form of metabolic acidosis was increased from 2 to 6 cases. In electrolyte parameters, serum sodium was reduced significantly (145±1.0 mEq/L vs. 141±0.8 mEq/L, p<0.01), but there was no case of significant hyponatremia (<135mEq/L). Bicarbonate level (20±1.1 mEq/L vs. 22±0.9 mEq/L, p< 0.05) and anion gap (19±1.6 mB vs. 13±1.3 mEq/L, p< 0.01) showed significant change. But, blood levels of potassium (3.6±0.1 mEq/L vs. 3.8±0.1 mEq/L, p=NS), chloride (106±0.6 mEq/L vs. 106±0.6 mEq/L, p=NS) and F'aCO2 (36±1.mmHg vs. 37±1.5 mmHg, p=NS) were no significant change before and after gastric lavage. Conclusions: Gastric lavage with 10 liters of 0.9% NaC1 in acute drug intoxication patients did not show clinically significant changes in electrolytes and acid-base balance.

Purification of the Coolant for Hot Roller by Superconducting Magnetic Separation

Tae-Hyung Kim,Dong-Woo Ha,Jun-Mo Kwon,Myung-Hwan Sohn,Seung-Kyu Baik,Sang-Soo Oh,Rock-Kil Ko,Ho-Sup Kim,Young-Hun Kim,Seong-Kuk Park IEEE 2010 IEEE transactions on applied superconductivity Vol.20 No.3

<P>It is important to recycle industrial wastewater in the aspect of energy saving and minimizing the environment damage. Steel manufacture factories make an effort to purify and recycle wastewater from the manufacturing processes. A steel manufactory in Korea, POSCO (POhang iron and Steel COmpany) has also concerned about the treatment of wastewater for long time. The coolant of hot roller at steel making factory includes suspended solid (SS) like steel fines, iron oxide and emulsified oil. A laboratory-scale conduction cooled high temperature superconducting (HTS) magnet was used for high gradient magnetic separation (HGMS) systems. It consists of eight double-pancake sub-coils, two HTS current leads, a GM cryo-cooler and a cryostat without a radiation shield vessel. Sub coils were wound with 1 G HTS tapes of Sumitomo Electric Industries by wet-winding method. A Cryo-cooled high temperature superconducting magnet system with 70 mm room temperature bore and 250 mm of height was prepared. This magnet was used for batch type HGMS system. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Various magnetic seeding reactions were investigated to increase the reactivity of coagulation.</P>

The treatment of coolant wastewater of rolling plate process by High Gradient Magnetic Separation

Tae-Hyung Kim,Dong-woo Ha,Kim-Mo Kwon,Myung-Hwan Sohn,Seimg-Kyu Baik,Sang-Soo Oh,Rock-Kil Ko,Ho-Sup Kim,Young-Hun Kim,Seong-Kuk Park 한국초전도저온학회 (구 한국초전도저온공학회) 2009 한국초전도저온공학회논문지 Vol.11 No.4

우분뇨와 왕겨 혼합물의 정치식과 통기퇴적식 퇴비화 과정에서 CO2 및 NH3 가스 발생과 토마토 생육

홍지형,임요섭,양원모,김길용,손보균,박금주 한국환경농학회 1997 한국환경농학회지 Vol.16 No.2

비닐온실내의 간헐 통기방식의 우분뇨 퇴비화에서 발효열에 의한 근권토양의 지온변화와 CO₂ 및 부숙최기의 NH 가스발생양상을 조사하고 토마토 재배를 통하여 그 혜택을 구명하고자 수행하였다. 퇴비화시설 온실 30㎝깊이의 지중온도 변화는 퇴비재료의 부숙온도 상승에 따라 지중온도 증가를 보여 부숙개시후 1주일에 최고 32℃까지 상승하여 대조구에 비해 18℃의 차이를 보였고, 부숙개시 20일 후부터는 주발효의 종료와 함께 점차 온도감소를 나타냈으며 35일 이후는 23℃수준을 일정하게 유지하는 반면에 대조구인 관행온실의 지중온도는 70일동안 14∼15℃범위를 벗어나지 않아 퇴비발효열에 의한 토마토 근권토양의 가온효과가 확인되었다. 전 조사기간에 퇴비화 온실에서 발생되는 CO₂ 평균값은 782∼1154ppm으로 관행온실(대조구) 440∼462ppm수준에 비해서 1.7∼2.6배의 차이를 보였다. 간헐통기 퇴비화에서 발생하는 NH₃ 가스는 부숙개시 후 3∼10일내에 다량 방출되었으며, 5일째 조사시 최고치인 134ppm을 보인 후 감소하여 17일부터는 3∼4ppm수준을 나타냈다. 비닐하우스내 밀폐 강제통기 퇴비화방식은 퇴비재료가 부숙되는 동안 방출되는 CO₂와 발효열에 의한 광합성 증대와 작물근권 온도를 높여 주는 효과로 인해 토마토의 생육, 수량 및 당도의 증가를 보였으며 총과중의 경우 60%의 증수를 나타냈다. This study was performed to evaluate the influence of composting process with an intermittent aeration on the variation of rhizosphere soil temperature, CO₂ and NH₃ release, and the growth reponse of tomato plantlet in traditional and composting greenhouse. As the temperature of composting materials increased, rhizosphere soil temperature in 30㎝ depth rose up to 32℃ at one week after introduction. This was 18℃ higher than that of traditional greenhouse. After 20 days of active composting, temperature of rhizosphere soil started to decrease and remained constant at 23℃ after 35 days. For the traditional greenhouse, the averaged temperature ranged at 14∼15℃. This results showed that composting greenhouse had the greater effect on increasing the underground temperature. Average value of evoluted CO₂ from the composting greenhouse for 70 days was 782∼1154ppm. This was 1.7∼2.6 times higher than that of the traditional greenhouse with an average of 440∼462 ppm. NH₃ release was highest during 2∼10 days in intermittent aerated composting and reached to 134 ppm maximum on the 5th day, then decreased rapidly, and maintained at 3∼4 ppm after 17 days. Increased photosynthesis due to the CO₂ gas and a favorable rhizosphere environment due to the increased underground temperature resulted in improved growth, yield, and Brix degree of tomato fruit.

The treatment of coolant wastewater of rolling plate process by High Gradient Magnetic Separation

Kim, Tae-Hyung,Ha, Dong-Woo,Kwon, Jun-Mo,Sohn, Myung-Hwan,Baik, Seung-Kyu,Oh, Sang-Soo,Ko, Rock-Kil,Kim, Ho-Sup,Kim, Young-Hun,Park, Seong-Kuk The Korean Society of Superconductivity and Cryoge 2009 한국초전도저온공학회논문지 Vol.11 No.4

This study introduced wastewater treatment method by High Gradient Magnetic Separation (HGMS). HGMS treatment was high efficient method for various industrial wastewaters. The system is currently research state, but we have surveyed commercialize the technology for industry. In rolling plate process, coolant wastewater was recycled by sedimentation and sand filter system. It needs several large reservoirs and long time to remove suspended solid (SS) like metal fines and iron oxide in hot rolling plate making process. If removing rate of suspended solid in rolling coolant wastewater is improved by using HGMS system, the productivity of working process can be increased and the area of reservoir can be reduced. We manufactured high temperature superconducting HGMS system that had a purpose to treatment of coolant wastewater in rolling plate process. We fabricated the prototypes of magnetic matrix filter consisting of stainless steel 430 mesh, which is a core component in the magnetic separation system, In our basic preliminary experiment using HGMS system, it has been clear that the fine paramagnetic particles in the coolant wastewater obtained from rolling plate process of POSCO can be separated with high efficiency.

Installation and Power Grid Demonstration of a 22.9 kV, 50 MVA, High Temperature Superconducting Cable for KEPCO

Song-Ho Sohn,Hyung-Suk Yang,Ji-Hyun Lim,Seung-Ryle Oh,Seong-Woo Yim,Su-Kil Lee,Hyun-Man Jang,Si-Dole Hwang IEEE 2012 IEEE transactions on applied superconductivity Vol.22 No.3

<P>Korea Electric Power Corporation (KEPCO) has a great interest on the application of HTS cable to its network to relieve power congestion and enhance the reliability of the power system. Down through the years from 2005 to 2010, the 22.9 kV, 50 MVA HTS cable has been demonstrated by field test, showing affirmative results. With the financial support of Ministry of Knowledge and Economy (MKE), the new project to install and operate the HTS cable in electrical network of Korea was launched in 2008. An HTS cable with the 22.9 kV, 50 MVA, and 410 m length was installed in the KECPO grid in the end of 2010. After the integration of the HTS cable system, the commissioning items of the DC withstand voltage test, DC critical current test, and heat loss measurements were conducted in accordance with the Korean industrial standard, and self-defined specifications. The HTS cable was energized on the 154 kV Icheon substation of KEPCO on August 19th, 2011. The details of the project description, onsite installation, and commissioning tests are presented in this paper.</P>

Compact Microstrip Resonant Cell을 ol용한 전력증폭기의 선형화 개선에 관한 연구

손형길,양승인,Sohn Hyung-Kil,Yang Seung-In 한국전자파학회 2005 한국전자파학회논문지 Vol.16 No.2

본 논문에서는 Compact Microstrip Resonant Cell을 이용하여 새로운 방법으로 선형성을 개선시킨 전력증폭기를 설계하였다. 전력증폭기의 입력단에 CMRC를 적용하였고, 입력단과 출력단에 각각 Tuning Line을 달아서 조정을 한 결과 기존의 전력증폭기보다 현저한 선형성을 보였다. 그 결과 CMRC를 적용한 전력증폭기는 기존의 전력증폭기보다 3차 IMD가 14.77 dB 만큼 개선되었다. CMRC의 크기는 $17.1\times5.22mm$이다. A new method of power amplifier's linearity improvement using a Compact Microstrip Resonant Cell(CMRC) is proposed. It is found out that a CMRC at the input side gives better performance than that at the output. Tuning lines are used in the input and the output matching network to get the optimum performance. As a result, the 14.77 dB improvement fur the third-order IMD is obtained. And the size of the CMRC is only $17.1\times5.22mm$.