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

본 논문은 X-band에서 동작하는 마이크로스트립 원형 편파 $4{\times}4$ 배열 안테나의 설계와 제작에 대해 다룬다. 단일 안테나는 정사각형 패치를 사용하고 비대칭 십자 개구 결합 급전 구조를 사용하여 RHCP(Right Handed Crcularly Polarization)로 동작하도록 하였다. 기존의 배열 안테나의 소자간의 간격을 0.8 ${\lambda}_0$에서 0.45 ${\lambda}_0$로 간격을 줄여 실장 면적을 감소시켰다. 급전 선로는 시퀀셜 로테이션 분배기로 $2{\times}2$ 배열 안테나를 설계하여 양호한 이득과 축비 대역폭을 나타내었다 ${\lambda}/4$ Transformer와 T-junction 전력 분배기로 $4{\times}4$ 배열 안테나로 확장하였다. 시뮬레이션으로 확인한 결과 최대 방사 이득은 15.09 dBi로 나타났으며, 축비 대역폭은 3 dB 기준 $9.05{\sim}10.4$ GHz(13.5%)의 양호한 특성을 보였다. 제작된 $4{\times}4$배열 안테나는 10 GHz에서 측정 결과 임피던스 대역폭($VSWR{\leq}2$)은 $8.45{\sim}11.84$ GHz(33.9%)로 나타났으며, 최대방사 이득은 11.10 dBi를 얻었다. 또한 측정된 축비 대역폭은 $9.42{\sim}10.47$ GHz(10.5%)를 얻었다. 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.

Isoguanosine과 Berberine 1 : 1 혼합물의 항암효과

김정한,이상준,한영복,문정조,김종배,Kim, Jung-Han,Lee, Sang-Jun,Han, Young-Bok,Moon, Jung-Jo,Kim, Jong-Bae 대한약학회 1994 약학회지 Vol.38 No.2

Isoguanosine and berberine 1:1 mixture[l:[1(mole:mole)] has been prepared and evaluated by measuring antitumor effects against various tumor cell lines in culture and in mice. We reported that the synergistic effect of isoguanosine and berberine mixture has been revealed compared with each of isoguanosine and berberine increased by $3{\sim}8$ times than that of each components in various tumor cell lines in vitro. The most effective dose of isoguanosine and berberine mixture was 60 mg/kg/day in mice bearing S-180 solid tumor, the %(1-T/C) values were 70%. Against the P-388 leukemia, isoguanosine-berberine mixture was the most effective at the dose of 60 mg/kg/day, the %T/C values were 163%.

한국인 사체에서의 정상 종골의 실측: 예비보고

김정한,곽희철,김전교,정양환,Kim, Jung-Han,Gwak, Heui-Chul,Kim, Jeon-Gyo,Jung, Yang Hwan 대한족부족관절학회 2014 대한족부족관절학회지 Vol.18 No.1

Purpose: The purpose of this report is to evaluate the measured values of normal Korean calcaneus by conduct of a cadaveric study. Materials and Methods: A total of 42 calcanei were obtained from Korean cadavers. A digital goniometer was used for measurement of B$\ddot{o}$hler's angle, Gissane angle, posterior facet articular inclination angle, and Fowler-Philip angle of calcaneus. A vernier caliper was used for measurement of the maximal antero-posterior length, maximal transverse width, and maximal height of calcaneus. Results: The average B$\ddot{o}$hler's angle, Gissane angle, posterior facet articular inclination angle, and Fowler-Philip angle was $32.3^{\circ}{\pm}5.0^{\circ}$, $114.4^{\circ}{\pm}8.2^{\circ}$, $61.2^{\circ}{\pm}4.4^{\circ}$, and $60.3^{\circ}{\pm}7.6^{\circ}$. The average maximal antero-posterior length, maximal transverse width, and maximal height of calcaneus was $74.2{\pm}3.0mm$, $43.0{\pm}4.0mm$, and $42.5{\pm}3.0mm$. Conclusion: The measured values of normal Korean calcaneus were lower than the values reported in the international literature. Therefore, development of appropriate instruments reflecting the anatomical characteristics of Koreans will be needed.

두 개의 기생 패치를 갖는 고 이득.광대역 SAP 안테나

김정한,김용진,이홍민,Kim, Jung-Han,Kim, Yong-Jin,Lee, Hong-Min 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.8

본 논문에서는 SDMB(Satellite Digital Multimedia Broadcasting) 시스템에서 동작하는 고 이득 광대역 안테나를 구현하였다. 제안된 안테나는 표면파를 억제하기 위한 SAP(Shorted Annular Patch) 구조와 이득, 대역폭 그리고 지향성을 개선시키기 위하여 $0.25 {\lambda}_0$ 간격을 갖는 3차원 배열의 기생 SAP로 구성되었다. 원형 패치상의 서로 반대 방향으로 농인 두 개의 슬릿을 이용하여 RHCP(Right Hand Circular Polarization)로 동작하도록 하였다. 모의 실험 결과, 제안된 안테나의 최대 방사 이득은 기존의 마이크로스트립 패치 안테나에 비해서 5.22 dBi 개선된 12.6 dBi로 나타났다. 제작된 안테나는 동작 주파수 2.63 GHz에서 최대 방사 이득이 10.5 dBi로 나타났다. 측정된 임피던스 대역폭$(VSWR{\leq}2)$은 기존의 마이크로스트림 패치 안테나에 비해서 300 MHZ 개선된 $360 MHz(2.488{\sim}2.848 GHz)$이며, HPBW(Half Power Beam Width)는 $45.8^{\circ}$, FBR(Front Back Ratio)은 15.49dBi로 나타났다. 3dB 축비 대역폭은 220 MHz$(2.54{\sim}2.76 GHz)$를 얻었다. In this paper, the high gain and broadband antenna operating for SDMB(Satellite Digital Multimedia Broadcasting) system is realized, The proposed antenna consists of the SAP(Shorted Annular Patch) structure, which inhibits surface-wave and the parasitic SAP element with spacing of $0.25 {\lambda}_0$ in order to improve gain, bandwidth and directivity. The RHCP(Right Hand Circular Polarization) is generated by two slits, which are made along the periphery of the circular patch at the diametrically opposite points, The simulated maximum gain of the proposed antenna is 12.6 dBi, which is better 5.22 dBi than maximum gain of the conventional microstrip patch antenna. The measured maximum gain is 10.5dBi at operating frequency 2.63GHz. Also, the measured impedance bandwidth$(VSWR{\leq}2)$ of the proposed antenna is $360MHz(2.488{\sim}2.848 GHz)$, which is better 300 MHz than the bandwidth of the conventional microstrip patch antenna. The measured HPBW(Half Power Beam Width) of the proposed antenna is $45.8^{\circ}$, and the measured FBR(Front to Back Ratio) is 15.49 dBi, The 3dB axial ratio bandwidth is 220 MHz$(2.54{\sim}2.76 GHz)$.

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.

소독제가 개인용 트레이와 실리콘 인상재의 접착력에 미치는 영향에 대한 연구

김정한,정창모,전영찬,황의성,Kim, Jung-Han,Jeong, Chang-Mo,Jeon, Young-Chan,Hwang, Hic-Seong 대한치과보철학회 1996 대한치과보철학회지 Vol.34 No.2

The effects of impression tray disinfection procedures on the bond strength of impression-material adhesive to two of types resin trays were evaluated with a tensile test. Autopolyme-rizing acrylic resin was formed into 1x1x1 cm cubes. A hook was attached to each cube with autopolymerizing acrylic resin. Perforated trays were fabricated with stops to maintain an even 3 cm of impression material over the resin block. Hook on the opposite side of the perforated tray permitted attachment of the metal plate to a mechanical testing machine. Before adhesive was applied, one third of the resin specimens were immersed in a 5% sodium hypochlorite solution : one third in a 2% glutaradehyde solution, and one third were kept in the "as fabricated" condition. Three products(Perfect ups, Exafine, and Exp-ress) of polyvynil siloxane impression material-adhesive system were evaluated. The resin-impression material-metal plate couples were attached to a mechanical testing machine and tensile forces were applied at a separation rate of 10 centimeters per second. The results were as follows; 1. Both disinfectant and adhesive had effects on bond strength values, but adhesive had more effect than disinfectant(p<0.01). However, there was no interaction between dinin-fectant and adhesive(p>0.01). 2. Mean bond strength values for the Perfect materials were about 85% less than that of the Exafine or the Express materials. However, there was no stastically significant difference between the mean bond strength values of the Exafine materials and the Express materials(p>0.05). 3. The use of disinfectants produced significant reduction in bond strength values(p<0.05). But there was no stastically significant difference between the mean bond strength values of the groups treated with disinfectants(p>0.05).

종골의 사체 실측 결과와 방사선학적 측정 결과의 비교

김정한,곽희철,이창락,정동우,노상명,Kim, Jung-Han,Gwak, Heui-Chul,Lee, Chang-Rack,Jeong, Dong-Woo,Roh, Sang-Myung 대한족부족관절학회 2015 대한족부족관절학회지 Vol.1 No.2

Purpose: We wanted to compare the results between cadaveric and radiological measurements of calcaneus. Materials and Methods: Sixty three calcaneus of 33 cadavers donated between December 2012 and December 2014 were actually measured. Computed tomography (CT) images of 244 calcaneus in 122 patients of the same age group with cadavers were radiologically measured. Maximum length, maximum width, maximum height, $B{\ddot{o}}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were measured. Results: In cadaveric measurement, the mean maximal height, length, and width were $41.8{\pm}3.3mm$, $73.3{\pm}3.4mm$, and $40.7{\pm}2.2mm$, respectively. In radiological measurement, the mean maximal height, length, and width were $38.5{\pm}4.3mm$, $74.0{\pm}5.7mm$, and $44.7{\pm}1.4mm$, respectively. In cadaveric measurement, the mean $B\ddot{o}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were $32.1^{\circ}{\pm}6.2^{\circ}$, $110.8^{\circ}{\pm}8.1^{\circ}$, $55.8^{\circ}{\pm}6.8^{\circ}$, and $59.7^{\circ}{\pm}4.6^{\circ}$, respectively. In radiological measurement the mean $B{\ddot{o}}hler$ angle, Gissane angle, Fowler-Phillip angle, and tala-articular angle were $32.6^{\circ}{\pm}3.8^{\circ}$, $113.7^{\circ}{\pm}5.7^{\circ}$, $62.2^{\circ}{\pm}3.9^{\circ}$, and $61.6^{\circ}{\pm}6.3^{\circ}$, respectively. The mean maximal height was significantly higher in the cadaveric measurement group (p<0.001) and the mean maximal length and width were significantly higher in the radiologic measurement group (p<0.001, p<0.001). The mean Gissane angle, Fowler-Philip angle, and $B{\ddot{o}}hler$ angle were significantly higher in the CT group (p=0.001, p<0.001, p=0.016, respectively). There was no significant difference in the mean tala-articular angle (p=0.352). Conclusion: Significant differences in length parameters were observed between the cadaveric measurement group and the radiologic measurement group. However, no significant differences in angular measurements were observed between the two groups. The authors carefully conclude that radiological measurement values may be different from actual values in the calcaneus.

추계학적 그린함수법으로 합성된 지반운동에 대한 단층 파라미터의 영향

김정한,서정문,최인길,Kim, Jung-Han,Seo, Jeong-Moon,Choi, In-Kil 한국지진공학회 2012 한국지진공학회논문집 Vol.16 No.1

이 연구에서는 추계학적 그린함수법에 의한 단층 모델을 이용하여 지진파를 합성하고 단층 파라미터의 변화에 의한 지반 운동의 차이를 평가하였다. 모멘트 규모 6.5의 단층을 예제로 선정하였고 아스페리티 면적의 통계값을 이용하여 슬립의 분포를 모델링하였다. 평가를 위해 고려된 단층 파라미터들은 진원의 위치, 전단파 속도 대비 파열 전파속도 비, 상승시간, 절점주파수 그리고 고주파감쇠 필터 등 이었다. 요소지진원에 적용된 파라미터들은 구조권역별 특성이 다른 지역의 값을 사용하였고 다른 파라미터들은 발생 가능한 임의의 값을 사용하였다. 생성된 지반운동 시간이력으로부터 응답스펙트럼을 작성하였으며, 파라미터의 값을 달리하여 비교하였다. 이로부터 각각의 단층파라미터에 의해 영향을 받는 주파수 구간 및 스펙트럼 가속도의 차이를 평가하였다. In this study, the ground motion was synthesized using the finite fault model by the stochastic green function method, and the difference in the ground motions was evaluated by using various values of the source parameters. An earthquake with a moment magnitude of 6.5 was assumed for the example fault model. The distribution of the slip in the fault plane was calculated using the statistical data of the asperity area. The source parameters considered in this study were the location of the hypocenter in the fault plane and the ratio of the rupture to the shear wave velocity, the rise time, the corner frequency of the source spectrum, and a high frequency filter. The values of the parameters related to the stochastic element source model were adjusted for different tectonic regions, and the others were selected for several possible cases. The response spectra were constructed from the synthesized ground motion time history and compared with the different parameter values. The frequency range affected by each parameter and the differences of the spectral accelerations were evaluated.

Mg-11Li-3Zn-1Sn-0.4Mn 마그네슘 합금의 Ca 첨가에 따른 미세조직 및 기계적 특성평가

김정한,김용호,유효상,손현택,이성희,Kim, Jung-Han,Kim, Yong-Ho,Yoo, Hyo-Sang,Son, Hyeon-Taek,Lee, Seong-Hee 한국재료학회 2015 한국재료학회지 Vol.25 No.6

The effect of adding Ca on the microstructural and mechanical properties of as-cast Mg-11Li-3Zn-1Sn(wt%) alloys were investigated. Mg-11Li-3Zn-1Sn-0.4Mn with different Ca additions (0.4, 0.8, 1.2 wt%) were cast under an $SF_6$ and $Co_2$ atmosphere at $720^{\circ}C$. The cast billets were homogenized at $400^{\circ}C$ for 12h and extruded at $200^{\circ}C$. The microstructural and mechanical properties were analyzed by OM, XRD, SEM, and tensile tests. The addition of Ca to the Mg-11Li-3Zn-1Sn-0.4Mn alloy resulted in the formation of $Ca_2Mg_6Zn_3$, MgSnCa intermetallic compound. By increasing Ca addition, the volume fraction and size of $Ca_2Mg_6Zn_3$ with needle shape were increased. This $Ca_2Mg_6Zn_3$ intermetallic compound was elongated to the extrusion direction and refined to fine particles due to severe deformation during hot extrusion. The elongation of the 0.8 wt% Ca containing alloy improved remarkably without reduction strength due to the formation of fine grain and $Ca_2Mg_6Zn_3$ intermetallic compounds by Ca addition. It is probable that fine and homogeneous $Ca_2Mg_6Zn_3$ intermetallic compounds played a significant role in the increase of mechanical properties.