CONTROL OF NUMBER OF COMPANIES

홍승환 한국보험학회 1964 保險學會誌 Vol.1 No.-

Effects of Initiator type on LDPE/EVA Radical polymerization in Tubular reactor

홍승환,최연범,이구형,최창현 한국고분자학회 2011 한국고분자학회 학술대회 연구논문 초록집 Vol.2011 No.2

부위마취 하에 대량 수혈이 필요한 고관절 수술을 받는 노인 환자에서 Dexmedetomidine의 진정 효과

홍승환,김건희,길호영,김미름 대한노인병학회 2012 Annals of geriatric medicine and research Vol.16 No.1

A revision total hip arthroplasty (THA) that anticipated massive bleeding and the need for blood transfusion was scheduled. The patient was a 73-year-old man who had well controlled hypertension. A combined spinal and epidural anesthesia was performed. Dexmedetomidine was administered from the beginning of the arterial and central line catheterization, until the end of the operation. During the 10 hours and 30 minutes surgery, the estimated blood loss was about 7,000 mL, with a total infused red blood cell amount of 14 units, total fresh frozen plasma of 6 units, a total crystalloid of 6,850 mL and of colloid 1,500 mL. The Ramsay sedation score was maintained within 3 and the hemodynamic condition was stable. We found that dexmedetomidine can be safely used for sedation, even during an operation requiring massive transfusions and a prolonged operation time.

고해상도 SAR 영상의 기하 위치정확도 관련 중요변수 분석

홍승환,손홍규,김상필,장효선 한국측량학회 2013 한국측량학회지 Vol.31 No.6

The geolocation accuracy of SAR satellite imagery is affected by orbit and sensor information and externalvariables such as DEM accuracy and atmospheric delay. To predict geolocation accuracy of KOMPSAT-5 andKOMPSAT-6, this paper uses TerraSAR-X imagery which has similar spec. Simulation data for sensitivityanalysis are generated using range equation and doppler equation with several key error sources. As a result ofsimulation analysis, the effect of sensor information error is larger than orbit information error. Especially, onboardelectronic delay needs to be monitored periodically because this error affects geolocation accuracy of slantrange direction by 30m. Additionally, DEM accuracy causes geolocation error by 20~30m in mountainous areaand atmospheric delay can occur by 5m in response to atmospheric condition and incidence angle. SAR 위성 영상의 기하 위치정확도는 크게 시스템 내적 변수인 위성 궤도 및 센서 정보와 시스템 외적 변수인DEM 오차, 대기 지연 등에 영향을 받는다. 이러한 변수들이 현재 운용 중인 다목적실용위성 5호와 개발 중인 다목적실용위성 6호의 영상 내 기하 위치정확도에 미치는 영향을 분석하기 위하여 유사한 제원을 지닌 TerraSAR-X 영상을 이용하여 연구를 수행하였다. 오차 분석을 위해 경사거리 방정식과 도플러 방정식을 이용하여 시뮬레이션 데이터를 생성하였으며, 위성 궤도 변수, 센서 변수, 시스템 외적 변수에 대한 오차를 지상 좌표와 영상 좌표 간 관계식에 반영하여 해당 변수들에 대한 민감도 분석을 수행하였다. 오차 분석을 통해 저궤도 위성의 위치 및 속도 정보로 인한 영상 내 오차는 이중주파수 GPS 데이터 이용에 따라 20cm 내외로 크지 않음이 확인되었다. 따라서 센서관련 변수들이 위치정확도에 영향을 줄 수 있으며, 특히 센서 내 전자적 시간 지연은 경사거리 방향의 정확도에 영향을 크게 미쳐 지속적인 모니터링이 필요할 것으로 판단되었다. 시스템 변수 외에도 DEM 정확도에 의한 오차로인해 산지지역에서 영상 Geocoding 시 오차가 20~30m까지 크게 발생하고, 대기 지연 현상에 의해 오차는 입사각에 따라 5m까지 발생할 수 있어 영상 활용 시 이에 대한 고려가 필요함이 확인되었다.

지상레이저스캐닝 기반 3차원 실내 모델링

홍승환,조형식,김남훈,손홍규,Hong, Seung Hwan,Cho, Hyoung Sig,Kim, Nam Hoon,Sohn, Hong Gyoo 대한토목학회 2015 대한토목학회논문집 Vol.35 No.2

3차원 실내공간정보에 구축 시 경제성, 효율성 및 정확도 향상을 위한 지상레이저스캐너의 활용이 주목을 받고 있다. 그러나 실내공간정보 구축에 있어 지상레이저스캐너 관측방식과 기존 측량방식 방식에 대한 비교 연구는 미비한 실정이다. 본 연구에서는 설계도면 갱신 및 3차원 실내 모델링에 AMCW 방식 및 direct TOF 방식의 지상레이저스캐너와 토탈스테이션의 작업시간 및 위치정확도를 비교하여 지상레이저스캐너의 효율성과 경제성을 제시하였다. 비교결과, AMCW 방식은 direct TOF 방식에 비해 시간효율성이 뛰어났으며 두 관측값 사이의 RMSE는 ${\pm}1mm$ 수준으로 나타났다. 또한 지상레이저스캐닝 방식은 토탈스테이션 관측방식에 비해 2배 이상의 시간효율성을 보였으며 두 관측값 사이의 RMSE는 ${\pm}3.4cm$로 나타났다. 제시된 지상레이저스캐너를 이용한 3차원 실내모델링의 경제성과 효율성을 바탕으로 향후 3차원 실내공간 정보 구축에 지상레이저스캐닝 방식이 효과적으로 활용될 수 있을 것으로 기대된다. According to the increasing demand for 3D indoor spatial information, the utilization of a terrestrial laser scanner comes to the fore. However, the research for the comparison between a terrestrial laser scanning method and a traditional surveying method is insufficient. The paper evaluated the time-efficiency and the locational accuracy of an AMCW type and a direct TOF type of terrestrial laser scanning methods in comparison with the observation using a total station. As a result, an AMCW type showed higher time-efficiency than a direct TOF type and the RMSE between the two types of data was ${\pm}1mm$. Moreover, the terrestrial laser scanning method showed twice higher time-efficiency than the observation using a total station and the RMSE between the two data was ${\pm}3.4cm$. The results indicate that the terrestrial laser scanning method has better profitability and performance for 3D indoor modeling than the traditional survey using a total station. In the future, a terrestrial laser scanner can be efficiently utilized in the construction of 3D indoor spatial information.

Gold Nanoparticle and Polymerase Chain Reaction (PCR)-Based Colorimetric Assay for the Identification of Campylobacter spp. in Chicken Carcass

홍승환,서건호,윤성호,김수기,천정환 한국축산식품학회 2023 한국축산식품학회지 Vol.43 No.1

Campylobacteriosis is a common cause of gastrointestinal disease. In this study, we suggest a general strategy of applying gold nanoparticles (AuNPs) in colorimetric biosensors to detect Campylobacter in chicken carcass. Polymerase chain reaction (PCR) was utilized for the amplification of the target genes, and the thiolated PCR products were collected. Following the blending of colloid AuNPs with PCR products, the thiol bound to the surface of AuNPs, forming AuNP-PCR products. The PCR products had a sufficient negative charge, which enabled AuNPs to maintain a dispersed formation under electrostatic repulsion. This platform presented a color change as AuNPs aggregate. It did not need additional time and optimization of pH for PCR amplicons to adhere to the AuNPs. The specificity of AuNPs of modified primer pairs for mapA from Campylobacter jejuni and ceuE from Campylobacter coli was activated perfectly (C. jejuni, p-value: 0.0085; C. coli, p-value: 0.0239) when compared to Salmonella Enteritidis and Escherichia coli as non-Campylobacter species. Likewise, C. jejuni was successfully detected from artificially contaminated chicken carcass samples. According to the sensitivity test, at least 15 ng/μL of Campylobacter PCR products or 1×103 CFU/mL of cells in the broth was needed for the detection using the optical method.

강인제어기가 장착된 2축 서보메커니즘의 최적튜닝

홍승환,정성종 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

An optimal tuning method of the cross-coupled controller linked with feed forward controllers and disturbance observers is proposed to reduce the contouring and tracking errors in this paper. To derive an accurate dynamic model of a mechanical subsystem for the optimal tuning, system identification procedure has been conducted through the sine sweep method. To apply the integrated tuning method to the optimal tuning problem, a nonlinear constrained optimization problem including relevant controller parameters of the servomechanism has been formulated. Optimal gains have been obtained through the SQP method. Experimental results show that both tracking and contouring errors are significantly reduced by applying the proposed robust controller and the integrated tuning method.

족저 근막염의 초음파 영상학적 형태

홍승환,주인탁,정현우,Hong, Seung-Hwan,Chu, In-Tak,Chung, Hyun-Woo 대한족부족관절학회 2007 대한족부족관절학회지 Vol.11 No.2

Purpose: This retrospective study was designed to evaluate the appearances of plantar fasciitis by ultrasonography. Materials and Methods: 48 cases of unilateral plantar fasciitis were enrolled in this study. Plain radiograph and realtime sonography of both feet were perfomred and the results were compared between the affected feet and controlateral symptomless feet. Calcaneal spur were observed on plain radiograph and thickness of plantar fascia, hypoechogenecity, blurring of border of plantar fascia, perifascial effusion, wavy plantar fascia were observed on sonography. Results: Women (35 cases) and left feet (30 cases) were more frequent than men and right feet. Thickness of plantar fascia in affected site was thicker than normal site (p<0.01). Hypoechogenecity was observed only in 39 cases (81%) affected site, blurring of border of plantar fascia in affected site was 30 cases (62%) and 7 cases (15%) in normal site, perifascial effusion was observed only in 38 cases (79%) affected site, wavy plantar fascia in affected site was 43 cases (90%) and 2 cases (4%) in normal site. Calcaneal spur in affected site was 36 cases (75%) and 33 cases (69%) in normal site. Conclusion: Sonography is a useful diagnostic procedure for the plantar fasciitis especially in the unilateral plantar fasciitis.

구리 산화물 계열 초전도체에서의 스핀 요동에 의한 자체 에너지의 엘리아시버그 계산

홍승환,최한용,Hong, Seung-Hwan,Choi, Han-Yong 한국초전도학회 2012 Progress in superconductivity Vol.13 No.3

We solve the momentum resolved d-wave Eliashberg equation employing the magnetic excitation spectrum from the inelastic neutron scattering on the LSCO superconductors reported by Vignolle et al. The magnetic excitation spectrum exhibits 2 peaks: a sharp incommensurate peak at 18 meV at momentum (${\pi}$, ${\pi}{\pm}{\delta}$) and (${\pi}{\pm}{\delta}$, ${\pi}$) and another broad peak near 40~70 meV at momentum (${\pi}$, ${\pi}$). Above 70 meV, the magnetic excitation spectrum has a long tail that is shaped into a circle centered at (${\pi}$, ${\pi}$) with ${\delta}$. The sign of the real part of the self-energy is determined by the momentum position of the peaks of the magnetic excitation spectrum and bare dispersion. We will discuss the effects of the each component of the magnetic excitation spectrum on the self-energy, the pairing self-energy.

Electrical Properties of Thin Film Transistors with Zinc Tin Oxide Channel Layer

홍승환,오규진,김은규 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.8

We have investigated thin film transistors (TFTs) with zinc tin oxide (ZTO) channel layer fabricated by using an ultra-high vacuum radio frequency sputter. ZTO thin films were grown at room temperature by co-sputtering of ZnO and SnO2, which applied power for SnO2 target was varied from 15 W to 90 W under a fixed sputtering power of 70 W for ZnO target. A post-annealing treatment to improve the film quality was done at temperature ranges from 300 to 600 C by using the electrical furnace. The ZTO thin films showed good electrical and optical properties such as Hall mobility of more than 9 cm2/V·s, specific resistivity of about 2 × 102 ·cm, and optical transmittance of 85% in visible light region by optical bandgap of 3.3 eV. The ZTO-TFT with an excellent performance of channel mobility of 19.1 cm2/V·s and on-off ratio (Ion/Ioff ) of 104 was obtained from the films grown with SnO2 target power of 25 W and post-annealed at 450 C. This result showed that ZTO film is promising on application to a high performance transparent TFTs.