시퀀셜 로테이션 분배기 구조를 이용한 X-band 마이크로스트립 4×4 광대역 원형 편파 배열 안테나

김정한,김중관,김용진,이홍민,Kim, Jung-Han,Kim, Joong-Kwan,Kim, Yong-Jin,Lee, Hong-Min 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.2

In this paper, the circularly polarized $4{\times}4$ array antenna is proposed for the X-band. A single antenna consists of square patch and unequal cross-aperture coupled feeding. The RHCP(Right Handed Circularly Polarization) is generated by unequal cross-aperture coupled feeding. By reducing space among elements of way antenna from 0.8 ${\lambda}_0$ to 0.45 ${\lambda}_0$, the mounting area of array antenna is miniaturized. The $2{\times}2$ array antenna is designed using sequential rotation feeding network. The good level of gain, axial ratio, and impedance bandwidth are achieved. The $4{\times}4$ array antenna is extended by ${\lambda}/4$ transformer and T-junction power divider. The simulated maximum radiation gain is 15.09 dBi at 10 GHz. The simulated 3 dB Axial Ratio bandwidth is from 9.05 to 10.4 GHz(13.5%). Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $4{\times}4$ array antenna is from 8.45 to 11.84 GHz(33.9%). The measured maximum radiation gain is 11.10 dBi at 10 GHz. The measured 3 dB Axial Ratio bandwidth is from 9.42 to 10.47 GHz(10.5%).

족근골 유합의 발생 빈도: 단일 기관 자기공명영상 분석

김정한,곽희철,이창락,김영준,김전교,이선주,이정한,박준호,Kim, Jung-Han,Gwak, Heui-Chul,Lee, Chang-Rak,Kim, Young-Jun,Kim, Jeon-Gyo,Lee, Sun-Joo,Lee, Jeong-Han,Park, Jun-Ho 대한족부족관절학회 2016 대한족부족관절학회지 Vol.20 No.3

Purpose: Tarsal coalition results from defects during the developmental stage and produes ankle pain and limitations in the range of motions. Its incidence has been reported to be 1%, but there has not been any reports with respect to Koreans. Therefore, we evaluated the prevalence of tarsal coalition in Koreans. Materials and Methods: Between 2005 and 2014, we analyzed a total of 733 cases of foot and ankle magnetic resonance imaging (MRI) in our hospital. There were 391 men and 342 women. All MRI readings were read by a radiologist in our hospital. We classified the coalitions in accordance with the histological and anatomical characteristics, and calculated the prevalence in each group. Moreover, we tried to determine the prevalence of tarsal coalitions in accordance with sex, age, and proportion of the symptomatic tarsal coalitions. Results: There were a total of 11 MRIs of tarsal coalition - 9 talocalcaneal coalitions, 1 calcaneocuboidal coalition, and 1 calcaneonavicular coalition. Nine tarsal coalitions were observed in men and 2 in women. Conclusion: Through this study, we found that the prevalence of tarsal coalition, including the asymptomatic patients, is similar to the previously known prevalence (1%). By getting more MRIs of the foot and ankle, we could better represent the prevalence of tarsal coalitions in Koreans.

농약의 물리화학적 특성 연구 (II) Flupyrazofos의 수용성, 가수분해, 증기압, 옥탄올/물 분배계수

김정한,김용화,김균,Kim, Jeong-Han,Kim, Yong-Hwa,Kim, Kyun 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.43 No.1

국내에서 최초로 합성, 개발된 유기인계 살충제인 flupyrazofos(KH-502)의 물리화학적 특성으로 수용성, 가수분해, 증기압, 분배계수를 EPA와 OECD 방법에 준하여 측정하였다. 수용성은 $25^{\circ}C$에서 0.80 ppm으로 낮았고 가수분해 반감기는 $25^{\circ}C$에서 266.5시간(pH 4.0), 180.0시간(pH 7.0), 120.9시간(pH 9.0)으로 알칼리 조건에서 불안정하였으며 $40^{\circ}C$에서는 $25^{\circ}C$보다 $2{\sim}4$배 정도 가수분해가 빠르게 진행되었다. 상은($25^{\circ}C$)에서의 증기압은 $2.81{\times}10^{-5}$ torr로 측정되었고, 다른 두 온도(35, $45^{\circ}C$)에서 증기압을 측정하여 log P=0.673-(1565.4/T)라는 관계식을 구하였다. Flupyrazofos의 상온($25^{\circ}C$)에서의 증기압은 diazinon과 유사한 수준이었고, DDVP보다는 약 1,000배 정도 낮은 수치로 휘발에 의하여 환경에 영향을 미칠 가능성은 낮을 것으로 판단되었다. Flupyrazofos의 옥탄올/물 분배계수치를 보면(log Kow=5.24) 먹이연쇄를 통한 생물농축이 예상되나 비교적 가수분해가 빠르기 때문에 비록 수계에 노출된다고 하여도 그 가능성은 매우 낮을 것으로 사료된다. Several physicochemical properties such as water solubility, vapor pressure, hydrolysis and octanol/water partition coefficient(Kow) of flupyrazofos, the first organophosphorus insecticide developed in Korea, were measured based on EPA and OECD methods. Water solubility was low showing 0.80 ppm at $25^{\circ}C$ and in hydrolysis study, half-life at $25^{\circ}C$ was 266.5 hr(pH 4.0), 180.0 hr(pH 7.0) and 120.9 hr(pH 9.0) demonstrating instability in alkaline solution. At $40^{\circ}C$ hydrolysis rate was $2{\sim}4$ times higher than that at $25^{\circ}C$. The equation log P=0.673-(1565.4/T) was obtained from vapor pressure experiments at three different temperatures (25, 35, $45^{\circ}C$) and $2.81{\times}10^{-5}$ torr was obtained at $25^{\circ}C$. This value is similar to that of diazinon and 1,000 times lower than that of DDVP suggesting it would not give environmental contamination by volatilization. High log Kow(5.24) was observed and this might result in bioconcentration through food chain. However, its possibility is not likely to be high due to its relatively rapid hydrolysis.

제초제는 잡초를 어떻게 죽이나? 1

김정한,Kim, Jeong-Han 한국작물보호협회 2006 자연과 농업 Vol.27 No.10

농약! 어디서 왔다가 어디로 가나?

김정한,Kim, Jeong-Han 한국작물보호협회 2006 자연과 농업 Vol.27 No.3

원위 경골 골절에서 금속정 및 금속판 고정술의 결과 비교

김정한,곽희철,이창락,정양환,Kim, Jung-Han,Gwak, Heui-Chul,Lee, Chang-Rack,Jung, Yang-Hwan 대한족부족관절학회 2015 대한족부족관절학회지 Vol.1 No.2

Purpose: We analyzed and compared the clinical and radiologic results between minimally invasive plate osteosynthesis and internal fixation using intramedullary (IM) nail in the treatment of distal tibia fractures. Materials and Methods: From March 2005 to June 2013, 65 cases of distal tibia fractures treated with either plate fixation or IM nail fixation were analyzed retrospectively by clinical and radiologic evaluations. The clinical results were compared using the American Orthopaedic Foot and Ankle Society (AOFAS) score, Olerud-Molander ankle score (OMAS), and visual analogue scale (VAS) score at the last follow-up. The radiologic results were compared by time to bone union, complications such as nonunion, delayed union, and malunion. Results: The clinical results (according to OMAS, AOFAS score, and VAS score) were 77.47, 84.76, and 1.75, respectively, in the plating group, and 90.21, 91.00, and 1.25, respectively, in the nailing group, and there was no statistically significant difference. Plating group showed earlier union than the nailing group and the nailing group showed higher frequency of non-union and delayed union than plating group. Conclusion: In treatment of distal tibia fractures, two methods showed appropriate results. Therefore, thorough investigation of the types of fracture, state of soft tissues, and advantages and disadvantages of the two methods should be conducted in the treatment of distal tibia fractures.

완관절의 초음파 소견 및 이용

김정한,김주용,권용욱,Kim, Jung-Han,Kim, Joo-Yong,Kwon, Yong-Uk 대한정형외과초음파학회 2014 대한정형외과 초음파학회지 Vol.7 No.2

We can test for small structures located at the surface layer as high resolution ultrasonic techniques and small probes were developed. Accordingly ultrasound became a useful tool in the diagnosis and treatment of wrist diseases. It is important to understand the anatomical structures and apply clinical features as well as these technical aspects when using ultrasound. The purpose of this article is to evaluate the usefulness and approach of ultrasound about typical diseases according to the area of the wrist pain.

Delta Ferrite Investigation on AISI 304 Stainless Steel Fabricated Continuous Casting (초)

김정한,( Seul Cham Kim ),( Do Hyun Kim ),( Tae Hong Ahn ),( Heung Nam Han ),( Kyu Hwan Oh ) 대한금속재료학회 2009 대한금속재료학회 학술대회 개요집 Vol.2009 No.-

일반화 공간변조를 위한 저복잡도 강인 최대 우도 신호 검파

김정한,윤태선,오세훈,이경천,Kim, Jeong-Han,Yoon, Tae-Seon,Oh, Se-Hoon,Lee, Kyungchun 한국정보통신학회 2017 한국정보통신학회논문지 Vol.21 No.3

In this paper, we propose a maximum likelihood signal detection scheme for a generalized spatial modulation system that activates only a subset of transmit antennas among multiple antennas and transmits information through the indexes of active antennas as well as through the transmit symbols. The proposed maximum likelihood receiver extracts a set of candidate solutions based on their a posteriori probabilities to lower the computational load of the robust receiver under channel information errors. Then, the chosen candidate solutions are exploited to estimate the covariance matrix of effective noise. Simulation results show that the proposed maximum likelihood detection scheme achieves better error performance than a receiver that does not take into account the channel information errors. It is also seen that it reduces the computational complexity with the same bit error rate performance as the conventional robust maximum likelihood receiver.

수업의 질 향상을 위한 과제

김정한,Kim, Jeong-Han 한국대학교육협의회 1992 大學敎育 Vol.59 No.-