BaF₂ 침전 및 불화물 용융염 전해 제련을 통한 폐 산세액 내 지르코늄 회수

한슬기,이영준,최정훈,이종현,Han, Seul Ki,Nersisyan, Hayk H.,Lee, Young Jun,Choi, Jeong Hun,Lee, Jong Hyeon 한국재료학회 2016 한국재료학회지 Vol.26 No.12

Zirconium(Zr) nuclear fuel cladding tubes are made using a three-time pilgering and annealing process. In order to remove the oxidized layer and impurities on the surface of the tube, a pickling process is required. Zr is dissolved in HF and $HNO_3$ mixed acid during the process and pickling waste acid, including dissolved Zr, is totally discarded after being neutralized. In this study, the waste acid was recycled by adding $BaF_2$, which reacted with the Zr ion involved in the waste acid; $Ba_2ZrF_8$ was subsequently precipitated due to its low solubility in water. It is very difficult to extract zirconium from the as-recovered $Ba_2ZrF_8$ because its melting temperature is $1031^{\circ}C$. Hence, we tried to recover Zr using an electrowinning process with a low temperature molten salt compound that was fabricated by adding $ZrF_4$ to $Ba_2ZrF_8$ to decrease the melting point. Change of the Zr redox potential was observed using cyclic voltammetry; the voltage change of the cell was observed by polarization and chronopotentiometry. The structure of the electrodeposited Zr was analyzed and the electrodeposition characteristics were also evaluated.

선형 홀센서의 기하학적 배치를 고려한 모터회전 주파수 추정기법

한슬기(Seul Ki Han),나원상(Won-Sang Ra),박진배(Jin Bae Park),윤태성(Tae Sung Yoon) 대한전기학회 2009 정보 및 제어 심포지엄 논문집 Vol.2009 No.10

In this paper, motor speed estimation using two linear hall sensors is considered. From the hall sensor outputs, a linear uncertain measurement equation including the stochastic parametric uncertainties in the measurement matrix is derived. So, motor speed estimation using two linear hall sensors becomes a conventional NCRKF(Non-Conservative Robust Kalman Filter) problem [1]. However, NCRKF makes a degradation of estimation performance if the statistical information on the stochastic parametric uncertainties is incorrect. To solve this problem, a motor speed estimation method based on CRKF(Constrained Robust Kalman Filter) is proposed in this study. Simulation results showed that the proposed motor speed estimation method based on CRKF can provide a reliable performance even under the statistical information on the parametric uncertainties in the measurement matrix being incorrect.

차량 충돌 방지 시스템을 위한 선형 순환 표적 추정기 설계

한슬기(Seul-Ki Han),나원상(Won-Sang Ra),황익호(Ick-Ho Whang),박진배(Jin-Bae Park) 대한전기학회 2011 대한전기학회 학술대회 논문집 Vol.2011 No.7

도로운송부문용 에너지 공급 시스템 설계 및 경제성평가

한슬기 ( Seul Ki Han ),김지용 ( Ji Yong Kim ) 한국화학공학회 2015 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.53 No.2

본 연구에서는 다양한 도로운송부문용 에너지 공급 시스템을 구축하고 각 시나리오의 최적 비용을 비교분석하였다.에너지 공급 시스템의 구성요소로써 기존의 정유공정, 부생수소 시스템, 신재생 에너지 자원 기반의 전력 생산공정,전력운송을 위한 전력망을 설정하였으며, 내연기관자동차, 전기자동차, 연료전지자동차 등 세 가지의 도로운송부문용 자동차를 포함하였다. 이러한 구성요소를 포함한 다양한 에너지 공급 시스템 시나리오를 기반으로 최적 생애주기비용을 규명할 수 있는 에너지 시스템 평가모델을 개발하였다. 본 연구에서 개발한 최적화 모델을 제주도 지역에 적용함으로써 모델의 성능을 검증하였고 또한 제주도 지역의 에너지 시스템 구축에 관한 다양한 시나리오의 경제성을 분석하였다. 제주도 도로운송부문용 에너지 공급 시스템의 생애주기비용 분석 결과, 전력망을 이용하여 전기를 공급하는 전기자동차 시나리오가 상대적으로 가장 높은 경제성을 보였으며, 신재생 에너지 자원을 이용하여 수소를 공급하는 연료전지자동차 시나리오가 가장 낮은 경제성을 보였다. 또한 연료비용, 차량비용, 인프라비용, 유지비용 등주요 비용 관련 변수들에 관한 민감도분석을 수행함으로써 생애주기비용의 변화에 주요한 구성요소들을 규명하였다. This study aims to design energy supply systems from various energy sources for transportation sectors and comparatively analyze the life cycle cost of different scenario-based systems. For components of the proposed energy supply system, we consider a typical oil refinery, byproduct hydrogen system, renewable energy source (RES)-based electric generation system and existing electricity grid. We also include three types of vehicles in transportation sector such as internal combustion engine vehicle (ICEV), electric vehicle (EV), fuel cell vehicle (FCV). We then develop various energy supply scenarios which consist of such components and evaluate the economic performance of different systems from the viewpoint of life cycle cost. Finally we illustrate the applicability of the proposed framework by conducting the design problem of energy supply systems of Jeju, Korea. As the results of life cycle cost analysis, EV fueled by electricity from grid is the most economically feasible. In addition, we identify key parameters to contribute the total life cycle cost such as fuel cost, vehicle cost, infra cost and maintenance cost using sensitivity analysis.

기밀성능 예측모델 보정에 따른 탑상형 공동주택의 수직 압력분포 예측결과 개선에 관한 연구

한슬기(Han Seul-Ki),이은지(Lee Eun-Ji),조수영(Jo Su-Young),정재원(Jeong Jae-Weon) 한국건축친환경설비학회 2014 한국건축친환경설비학회 논문집 Vol.8 No.5

The objective of this research is to verify the tuning process which is predict a pressure distribution in tower-type apartment building by simulation. It is evaluated that how accurate each model’s results compared with measurement of indoor pressure. Study in advance, the tuning process of building simulation is designed to predict air-tightness and the tuning precess show that it has validity. Therefore, whether the tuning process is valid or not is evaluated to predict stack effect in high-rise building. As a preliminary step, a high-rise building was selected and the pressure of elevator zone and stair hall was measurement on every floor to confirm the accuracy of simulation results. Also, the air leakage of building element was measured to enter into the model to tune. At first, the data of intial model is not adjusted. At next step, the model is tuned by replacing initial data obtained literature with experimental date. With each step of the tuning process, the simulation results are verified. The results show that the indoor pressure on each floor in simulation is similar to that of actual test.

김발형 초음파 이동음원 추적센서 개발을 위한 의사최적 도래각 추정기법

한슬기(Seul-Ki Han),이혜경(Hye-Kyung Lee),나원상(Won-Sang Ra),박진배(Jin Bae Park),임재일(Jae-II Lim) 대한전기학회 2012 전기학회논문지 Vol.61 No.2

In this paper, a practical quasi-optimal DOA(direction of arrival) estimator is proposed in order to develop a one-axis gimbaled ultrasonic source tracker for mobile robot applications. With help of the gimbal structure, the ultrasonic moving source tracking problem can be simply reduced to the DOA estimation. The DOA estimation is known as one of the representative long-pending nonlinear filtering problems, but the conventional nonlinear filters might be restrictive in many actual situations because it cannot guarantee the reliable performance due to the use of nonlinear signal model. This motivates us to reformulate the DOA estimation problem in the linear robust state estimation setting. Based on the assumption that the received ultrasonic signals are noisy sinusoids satisfying linear prediction property, a linear uncertain measurement model is newly derived. To avoid the DOA estimation performance degradation caused by the stochastic parameter uncertainty contained in the linear measurement model, the recently developed NCRKF (non-conservative robust Kalman filter) scheme [1] is utilized. The proposed linear DOA estimator provides excellent DOA estimation performance and it is suitable for real-time implementation for its linear recursive filter structure. The effectiveness of the suggested DOA estimation scheme is demonstrated through simulations and experiments.

대탄도탄 FMCW 탐색기를 위한 탄두부 추적 필터 설계

한슬기(Seul-Ki Han),나원상(Won-Sang Ra),박진배(Jin-Bae Park),홍영곤(Young-Gon Hong),박성호(Sung-Ho Park),선웅(Woong Sun) 대한전기학회 2012 전기학회논문지 Vol.61 No.5

In this paper, a practical warhead tracking filter is proposed for developing a FMCW (Frequency Modulation Continuous Wave) seeker with anti-ballistic missile capability. For reliable warhead tracking, the measurement originated from the warhead section of a ballistic target should be separated from other measurements. Futhermore, since the FMCW seeker is based on triangular frequency modulation, the multiple measurements obtained in different chirp periods should be properly associated. As a systematic way to solve the problem, the measurement pairing problem under cluttered environment is reformulated as a data association filtering problem and the PDA (Probabilistic Data Association) scheme is applied. The proposed warhead tracking filter provides better warhead tracking performance compared to the conventional range tracking algorithm and nearest neighbor warhead tracking filter. The effectiveness and reliability of the proposed method are verified using the FMCW seeker simulator.

국내외 공조기를 이용한 대형건물의 외피 기밀성능 측정 방법 및 조사

한슬기(Han Seul-Ki),조홍재(Cho Hong-Jae),박준영(Park Joon-Young),김민휘(Kim Min-Hwi),정재원(Jeong Jae-Weon) 한국건축친환경설비학회 2012 한국건축친환경설비학회 학술발표대회 논문집 Vol.2012 No.3

Over the last decades, many large scale or high-rise buildings have been constructed. In these buildings, air tightness is critical issue for raising the space cooling and heating load and occurring the stack effects. Therefore, it is important to measure the airtightness and air leakage rates in components of building to save energy. However, conventional bloor door test could not be suitable to measure the air tightness in large scale buildings. In this paper, air leakage test method using building air-handler unit is introduced. And it could be also provided that the practical way to estimate envelop leakage in large scale or high-rise building where a blower door test is not using. CGSB 149.15 was well known fan pressurization and de-pressurization test standard using air-handler fan. Based on CGSB 149.15, this paper provides information about the procedure of the air-handler fan pressurization test method.

스마트폰을 이용한 동적균형능력 측정의 타당도 연구

한슬기 ( Seul Ki Han ),이상용 ( Sang Yong Lee ),이대희 ( Dae Hee Lee ),박정서 ( Jung Seo Park ) 대한물리의학회 2016 대한물리의학회지 Vol.11 No.2

PURPOSE: The purpose of this study was to investigate the validity of dynamic balance measurements using a smartphone. METHODS: Thirty subjects were selected out of Y-university students without fractures, operation history, and inflammatory arthritis who had not started regular exercise during the past three months. Their dynamic balance ability was measured by the Biodex Balance System (Biodex Medical Systems, Inc., USA) using smartphones. The smartphone utilized in this study was the Galaxy Note4 LTE (SM-N910K, Samsung, Korea), and the application was the Sensor Kinetics pro (Ver.2.1.2, INNOVENTIONS Inc, US). The dynamic balance ability was measured in triplicate. RESULTS: With eyes closed, a low level of correlation (r>0.30, p<0.05) and low reliability (ICC>0.60) were determined between the roll value of the smartphone gyroscope versus the medial/lateral score of the Biodex Balance System. With eyes closed, a low level of correlation (r>0.30, p<0.05) and low reliability (ICC>0.60) were determined between the total value of the smartphone gyroscope versus the total score of the Biodex Balance System. CONCLUSION: This study indicated that using a smartphone can generate highly limited data regarding balance ability. They are unlikely to replace the existing more expensive devices entirely. However, smartphones may be highly useful in environments in which an expensive device is not available or when dynamic balance ability should be measured immediately or within a few hours.

인지로봇 청각시스템을 위한 의사최적 이동음원 도래각 추적 필터

한슬기(Seul-Ki Han),나원상(Won-Sang Ra),황익호(Ick-Ho Whang),박진배(Jin Bae Park) 제어로봇시스템학회 2011 제어·로봇·시스템학회 논문지 Vol.17 No.3

This paper proposes a quasi-optimal linear DOA (Direction-of-Arrival) estimator which is necessary for the development of a real-time robot auditory system tracking moving acoustic source. It is well known that the use of conventional nonlinear filtering schemes may result in the severe performance degradation of DOA estimation and not be preferable for real-time implementation. These are mainly due to the inherent nonlinearity of the acoustic signal model used for DOA estimation. This motivates us to consider a new uncertain linear acoustic signal model based on the linear prediction relation of a noisy sinysoid. Using the suggested measurement model, it is shown that the resultant DOA estimation problem is cast into the NCRKF (Non-Conservative Robust Kalman filtering) problem [12]. NCRKF-based DOA estimator provides reliable DOA estimates of a fast moving acoustic source in spite of using the noise-corrupted measurement matrix in the filter recursion and, as well, it is suitable for real-time implementation because of its linear recursive filter structure. The computational efficiency and DOA estimation performance of the proposed method are evaluated through the computer simulations.