http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
DPF 위치에 따른 엔진과 터보차저 성능 변화에 관한 영향의 수치 해석적 연구
김강욱(Kangwook Kim),송주헌(Juhun Song) 한국자동차공학회 2013 한국자동차공학회 지부 학술대회 논문집 Vol.2013 No.4
The objective of the study was to analyze the impact of DPF(Diesel Particulate Filter) place on the engine and turbocharger performance with GT-Power. The location of the after-treatment system within the exhaust system of a turbocharged diesel engine can have significant impact on the turbocharger and engine performance. The study is conducted in DPF of after-treatment system upstream of the turbocharger as opposed to the more conventional downstream location. This study has shown that turbocharger efficiency and BMEP(Brake Mean Effective Pressure) advantage exist for a pre-turbine configured DPF as compared to the post-turbine counterpart. Under the post-turbine configuration, When the speed of engine is low-speed, the performance is more efficient than the pre-turbine configuration. As the speed of engine increases, the results indicate that a pre-turbo configuration is more desirable than a post-turbine configuration in terms of BSFC(Brake Specific Fuel Consumption).
안테나 수치 해석 모델을 이용한 저항성 V 다이폴의 효율 분석
김강욱(Kangwook Kim),전종훈(Jonghoon Chun) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.2
저항성 V 다이폴을 수치적으로 해석하기 위하여 모멘트 방법(method of moments)에 기반을 둔 수치 해석 모델을 개발하였다. 수치 해석 모델의 성능을 입증하기 위하여 실험 모델을 만든 후 안테나에서 급전선으로 돌아오는 반사 계수를 측정하였다. 측정된 데이터와 수치 해석 모델에서 계산된 데이터는 매우 잘 일치하였고, 이로써 수치 해석 모델의 정확성을 입증하였다. 수치 해석 모델을 이용하여 안테나의 효율과 저항에서 소모되는 전력을 분석하였다. 분석 결과는 안테나가 부하 저항 때문에 낮은 복사 효율을 가진다는 것을 보였다. 또한, 안테나의 급전점과 가까운 곳에 위치한 저항이 급전점에서 먼 곳에 위치한 저항보다 많은 전력을 소모한다는 것을 보였다. 이 결과들은 저항성 V 다이폴이 받아들일 수 있는 최대 전력을 계산하거나 특정 응용을 위한 저항의 전력 등급을 결정하는데, 그리고 안테나의 작동 거리를 예상하는데 사용될 수 있을 것으로 보인다. A method of moments model for the resistive vee dipole has been established. In order to validate the numerical model, an experimental model is built and reflections from the antenna in the feed line are measured. The measured data and the numerical data agree closely validating the numerical model. Based on the numerical model, efficiency of the antenna and the power dissipated in the resistors are analyzed. The results show that the antenna has low radiation efficiency because of the loading resistors and that the resistors near the drive point of the antenna dissipate more power than do the resistors far from the drive point. The results can be used to determine the amount of power that can be accepted by the resistive vee dipole, to determine the power rating of the loading resistors for a desired application, or to estimate the operation range of the antenna.
1차원 합성 개구면을 가진 초광대역 레이더의 시영역 기반 영상화 기법 비교
김대만(Daeman Kim),홍진영(Jin-Young Hong),김강욱(Kangwook Kim) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.10
본 논문에서는 Delay-Sum Back Projection(DSBP) 기법과 finite-difference time-domain 방법으로 구현된 time reversal(FDTD-TR) 기법을 실험 데이터에 적용하고, 그 결과를 비교한다. 두 기법은 모두 시영역에 기반을 둔 기법으로서 초광대역 레이더 신호를 처리하여 표적의 실제 위치와 모양에 가까운 영상을 생성할 수 있다. 실험을 위한 초광대역 레이더는 네트워크 분석기, 저항성 V 다이폴 안테나, 스캐너, 제어 컴퓨터로 구성되며, 레이더 개구면은 안테나를 1차원 스캔하여 합성된다. 실험 데이터는 신호 왜곡과 클러터를 포함하는데, 이를 제거하는 보정 절차가 수행된다. 두 기법은 동일한 플랫폼에서 동일한 데이터에 적용되며, DSBP 기법은 FDTD-TR 기법에 비해 더 나은 영상을 생성하지만 더 많은 시간이 걸린다는 것을 보인다. Delay-sum back projection(DSBP) algorithm and the time reversal algorithm based on the finite-difference timedomain method are compared. The two algorithms, which operate in the time domain, can process the ultra-wideband (UWB) radar data to generate images that are close to the original location and shape of the target. For the experiment, the UWB radar consists of a network analyzer, a resistive V dipole antenna, a scanner, and a control computer. The radar aperture is synthesized by linearly scanning the antenna. A calibration procedure is applied to the measured data to remove signal distortion and clutter. The two algorithms are applied to the same data on the same platform. It is shown that the DSBP algorithm produces better images but takes longer time to produce the images than the FDTD-TR algorithm.
Pulsed UV를 이용한 CSOs 소독시 반사체에 따른 처리효율 연구
한종훈,허지용,김강욱,이준영,박원석,이종열,허남국,Han, Jonghun,Hur, Jiyong,Kim, Kangwook,Lee, Junyoung,Park, Wonseok,Lee, Jongyeol,Her, Namguk 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.1
This study examined the disinfection in combined sewer overflows (CSOs) by pulsed ultraviolet (PUV). The reflectors (stainless steel. mirror, aluminium foil, aluminium (1050), aluminium (6061), aluminium (5052), and aluminium mirror) of PUV irradiation was performed in a 90 L stainless reactor at a constant temperature of $20^{\circ}C$ and an applied power of 4000 W. The reflection efficiency of reflectors were showed 1.00 (aluminium mirror) ~ 1.48 (aluminium foil) does. The case of a rough surface analysis using SEM showed high reflectance, was the case of a smooth surface and a low reflectivity. Pseudo first-order rate constant calculated results, has a higher reflectivity values were more than twice as high compared to the low reflectivity. Affected Total coliforms disinfection time, depending on the type of reflector is considered.
효율적인 2-Methylisoborneol, Geosmin의 제거를 위한 Pulsed UV 공정과 Ultrasound 공정의 비교 연구
한종훈,허지용,김강욱,이준영,박원석,이종열,허남국,Han, Jonghun,Hur, Jiyong,Kim, Kangwook,Lee, Junyoung,Park, Wonseok,Lee, Jongyeol,Her, Namguk 한국지하수토양환경학회 2015 지하수토양환경 Vol.20 No.4
The degradation of off-flavors which is 2-Methylisoborneol (2-MIB) and geosmin by means of ultrasound (US) and pulsed ultraviolet (PUV) irradiation and its combination with catalyst (wire mesh, wire mesh coated TiO<sub>2</sub>, and TiO<sub>2</sub>) and additive (H<sub>2</sub>O<sub>2</sub>) were investigated via water system. A combination treatment of TiO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> heterogeneity with US (24 kHz) and PUV (6000 W) has shown improved results in destroying 2-MIB and geosmin, which may be attributed to chain reactions by the enhanced formation of hydroxyl radicals (·OH) through H<sub>2</sub>O<sub>2</sub> dissociation and reactive oxide ions of TiO<sub>2</sub> addition. Rapid degradation of off-flavors occurred within 2 min under PUV process with H<sub>2</sub>O<sub>2</sub> 100 mg/L (81.5% for 2- MIB; 79.3% for geosmin) and TiO<sub>2</sub> 100 mg/L (83.7% for 2-MIB; 79.8% for geosmin), while compared with H2O2 100 mg/L (58.4% for 2-MIB; 58.0% for geosmin) and TiO<sub>2</sub> 100 mg/L (59.2% for 2-MIB; 38.5% for geosmin) within 5 min under US process. Surprisingly, the emphasis was given on the comparison with the same injected energies between PUV and US on degradation efficiency. Based on the injected energy comparison, the US provided better degradation performance under equal input power of 200 kJ with H<sub>2</sub>O<sub>2</sub> 100 mg/L, while compared with H<sub>2</sub>O<sub>2</sub> 100 mg/L under PUV process. Our findings suggest that US can be more effective compared to PUV for the degradation of off-flavors in aspect of energy consumptions.
시영역 유한차분법을 이용한 초광대역 레이더의 영상화 기법 연구
김대만(Daeman Kim),김강욱(Kangwook Kim) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7
본 논문에서는 시영역 유한차분법(finitr-difference time domain, FDTD)방법으로 구현된 time reversal 기법을 적용하여 실험 데이터에 적용하였다. FDTD time reversal 기법은 시영역에 기반을 둔 기법으로서 초광대역 레이더 신호를 처리하여 표적의 실제 위치와 모양에 가까운 영상을 생성할 수 있다. 실험을 위한 초광대역 레이더는 네트워크 분석기, 저항성 V 다이폴 안테나, 스캐너, 제어 컴퓨터로 구성되며, 레이더 개구면은 안테나를 1차원 스캔하여 합성된다. 실험 데이터는 신호 왜곡과 클러터를 포함하는데, 이를 제거하는 보정 절차가 수행된다.
방사 패턴의 재구성이 가능한 루프-마이크로스트립 패치 결합형 안테나
김용진(Yongjin Kim),강웅(Woong Kang),김강욱(Kangwook Kim) 한국정보기술학회 2012 한국정보기술학회논문지 Vol.10 No.10
In this paper, we propose a beam pattern reconfigurable loop-microstrip patch combined antenna. The proposed antenna is consist of simple microstrip patch antenna, loop structure which is connected with patch, and switch elements. By controlling the state of switches, the proposed antenna works as a single patch antenna or a patch-loop combined antenna. Depending on the single patch mode or patch-loop combined mode, the antenna radiation pattern can be changed. The proposed antenna is designed to operate at 1.4 GHz band. The sizes of the rectangular patch and the ground plane are 46mm x 42mm and 98mm x 92mm, respectively. The simulated and measured results show that the antenna operates at approximately same frequency range, whereas it is observed the antenna radiation pattern can be changed with maximum gain of the proposed antenna is 4.42dBi.
무인 경계용 레이더 센서를 위한 2×2 패치 배열 안테나
임태빈(Taebin Im),김강욱(Kangwook Kim),조정삼(Jungsam Cho),강태인(Taein Kang),이노복(Nobok Lee) 한국정보기술학회 2010 한국정보기술학회논문지 Vol.8 No.11
2×2 path array antenna for surveillance sensor has been designed and fabricated. The radar senor needs an antenna whose bandwidth and gain are 7.2-8.2㎓ and 10dBi, respectively. To satisfy the bandwidth of the antenna, height of the dielectric substrate are increased by piling 4 sheets of dielectric substrate with pre-preg. To achieve a 10㏈i gain, 4 rectangular patch elements are placed in a 2×2 structure on the piled dielectric substrate. To reduce the loss and size of the feed network, hybrid feed network of a probe and microstrip transmission lines is used. The comparison of the simulated and measured performances of the antenna is in good agreement.