Theoretical and Numerical Study of Cylindrical-vector-mode Radiation Characteristics in Periodic Metallic Annular Slits and Their Applications

Hyuntai Kim,Yoonchan Jeong 한국광학회 2018 Current Optics and Photonics Vol.2 No.5

We investigate the radiation characteristics of radially polarized light and azimuthally polarized light through plasmonic subwavelength-scale annular slit (PSAS) structures, by means of both theoretical and numerical methods. Effective-medium theory was utilized to analyze the characteristics of PSAS structures, and the corresponding results showed that PSAS structures can function as a metallic medium for azimuthally polarized light, or as a low-loss dielectric medium for radially polarized light. Numerical calculations based on the finite-element method were also performed, to verify the theoretical analyses. It turned out that the numerical results supported the theoretical results. Moreover, we exploited the PSAS structures in novel nanophotonic elements with dual functionalities that could selectively focus or pass/block incident light, depending on its polarization state. For example, if PSAS structures were implemented in the dielectric region of a metallic Fresnel zone plate, the modified zone plate could function as a blocking element to azimuthally polarized light, yet as a focusing element to radially polarized light. On the contrary, if PSAS structures were implemented in the metallic region of a metallic Fresnel zone plate (i.e. the inverted form of the former), it could function as a focusing element to azimuthally polarized light, yet as a simple transparent element to radially polarized light.

Single Magnetic Bead Detection in a Microfluidic Chip Using Planar Hall Effect Sensor

Hyuntai Kim,Venu Reddy,Kun Woo Kim,Ilgyo Jeong,Xing Hao Hu,CheolGi Kim 한국자기학회 2014 Journal of Magnetics Vol.19 No.1

In this study, we fabricate an integrated microfluidic chip with a planar Hall effect (PHE) sensor for single magnetic bead detection. The PHE sensor was constructed with a junction size of 10 μm × 10 μm using a trilayer structure of Ta(3 nm)/NiFe(10 nm)/Cu(1.2 nm)/IrMn(10 nm)/Ta(3 nm). The sensitivity of the PHE sensor was 19.86 μV/Oe. A diameter of 8.18 μm magnetic beads was used, of which the saturation magnetization was ~2.1 emu/g. The magnetic susceptibility χ of these magnetic beads was calculated to be~0.14. The diluted magnetic beads solution was introduced to the microfluidic channel attributing a single bead flow and simultaneously the PHE sensor voltage was measured to be 0.35 μV. The integrated microchip was able to detect a magnetic moment of 1.98 × 10<SUP>?10</SUP> emu.

Theoretical study on the generation of a low-noise plasmonic hotspot by means of a trench-assisted circular nano-slit.

Kim, Hyuntai,Lee, Seung-Yeol,Koo, Sukmo,Kim, Jinseob,Park, Kyoungyoon,Lee, Dongyeul,Vazquez-Zuniga, Luis Alonso,Park, Namkyoo,Lee, Byoungho,Jeong, Yoonchan Optical Society of America 2014 Optics express Vol.22 No.22

<P>We propose a novel trench-assisted circular metal nano-slit (CMNS) structure implementable on a fiber platform for the generation of a low-noise cylindrical surface plasmon (CSP) hotspot. We design trench structures based on a multi-pole cancellation method in order that a converging surface plasmon signal is well separated from co-propagating non-confined diffracted light (NCDL) at the hotspot location. In fact, the secondary radiation by the quasi-pole oscillation at the edge of the trench cancels the primary NCDL, thereby enhancing the signal-to-noise ratio (SNR) of the CSP hotspot. In particular, we investigate two types of trench structures: a rectangular-trench (RT) structure and an asymmetric-parabolic-trench (APT) structure, which are considered for the sake of the simplicity of fabrication and of the maximal enhancement of the SNR, respectively. In comparison with a conventional CMNS having no trenches, we highlight that the mean SNR of the CSP hotspot is enhanced by 6.97 and 11.89 dB in case of the optimized RT and APT CMNSs, respectively. The proposed schemes are expected to be useful for increasing the SNR of plasmonic devices that are interfered by NCDL, such as various types of nano-slits for generating high-resolution plasmonic signals, for example.</P>

古典醫書에 나타난 導引氣功 方法에 대한 硏究

김현태(Hyuntai Kim),한창현(Changhyun Han),이상남(Sangnam Lee),박지하(Jiha Park) 한국한의학연구원 2009 한국한의학연구원논문집 Vol.15 No.2

Objectives : Because of emphasizing a side of preventive medicine in the oriental medicine, an interest in Doinqigong (導引氣功: Physical and breathing exercise) has been elated recently. But, it has a limited sphere of application in the present south korea. Therefore we would like to bring out its sphere of application and detailed method in the oriental medicine classics. Method : We have researched theories and methods of Doinqigong in the Junghwaeujeon(中華醫典: Oriental medicine classic collections) DB according to below the procedure. (1) Making a related words list: We have used existing study of Doinqigong to make a list. It has been connected with Doinqigong. It includes not only technical terms, but also general terms. (2) Searching sentences: We have searched sentence that contain terms related with Doinqigong in the Junghwaeujeon DB. (3) Analysis of related sentences: We have searched and classified sentence by theory and method. Result : Results & Conclusion : (1) The total number of oriental medicine classics connected with Doinqigong is twelve. (2) The methods of Doinqigong have classified into three large groups: They are the Doinqigong for preservationing of good health, the Doinqigong for curing disease and the Doinqigong for internal organs and channels. (3) The number of Doinqigong for preservationing of good health in the seven oriental medicine classics is about ten. For example, the Okeumhi(五禽戱: Five animal's dance), the Paldangeum(八段錦: Eight motions of qigong) and so on. The number of oriental medicine classics connected with Doinqigong for curing disease is seven. They contain internal diseases, surgical diseases, diseases of five sensory organs and various diseases in the order of their frequency. The Doinqigong for internal organs and channels is only the Yookjageul(六字訣: Six sound's treatment).

The Changing Roles of Ownership in the Economic Growth in China

Lee, Hyuntai Korea Consensus Institute(KCI) 2020 Analyses & alternatives Vol.4 No.2

This paper examines the changing roles of ownership in the economic growth by using a panel data set of 30 provinces in China for the period (1999-2010). With the use of absolute and relative presence variables, this study shows that private enterprises have emerged as the engine of economic growth in China in the later period (2005-2010). The growing size and number of private enterprises are positively linked to growth. However, though foreign-invested enterprises have been acclaimed as the main contributors to economic growth in China, they have minimal effect on the economic growth in the later period. State-owned enterprises have a significant and negative effect on the economic growth in the later period. The results can be interpreted that the engine of growth in China has been changed over time from other ownerships to private ownership. Private companies have developed a lot in every respect and started to lead the economy for long-run growth. China initiated its economic growth by adopting foreign capital and it is still the top destination for foreign direct investment among developing countries. However, to sustain the growth over a long period, private sector should be of great importance and perform a key role in the view of catch-up economics.

관배수 겸용암거의 관배수특성과 소요통수능분석

김현태 ( Hyuntai Kim ),정기열 ( Kiyuol Jung ),박영준 ( Youngjun Park ),유전용 ( Jeonyong Ryu ) 한국농공학회 2021 한국농공학회 학술대회초록집 Vol.2021 No.-

PVC 주름유공관 암거의 통수능 분석 및 시험시공사례

김현태 ( Hyuntai Kim ),정기열 ( Kiyuol Jung ),이상훈 ( Sanghun Lee ),유전용 ( Jeonyong Ryu ) 한국농공학회 2018 한국농공학회 학술대회초록집 Vol.2018 No.-

In order to confirm the field applicability of the PVC corrugated drain pipe used in the non-excavated subsurface drainage system, theoretical analysis on the subsurface discharge capacity of corrugated drain pipe by spacing was conducted and the adaptability was verified through test construction in the field. 1) According to the drainage design criteria, subsurface drainage capacity is required over 30mm/day to cultivate highland crops in the lowland field, and selection of spacing and diameter of drain pipe to drain the required subsurface discharge should be considered. 2) Hydraulic conductivity with k=1*10-⁵cm/s of soil above subsurface drain pipe in low and wet paddy fields can be improved through subsoil fracture. Improved hydraulic conductivity with k=8*10-⁵cm/s and 3*10-⁴cm/s of the soil make installation of the culvert spacing S=5m and 10m possible, respectively, to sufficiently drain the designed subsurface drainage discharge. 3) On the condition of pipe spacing 5m, pipe length 100m and hydraulic head 20cm, it was analyzed that the required diameter of the drain pipe satisfying the subsurface drainage design capacity of 30mm/day (considering safety factor 2) was sufficient. 4) As a result of test construction for non-excavated corrugated subsurface drain pipe with diameter of 50mm, length of 100m, and hydraulic head of 20cm in the field, it was confirmed that installation spacing with 5m of the drain pipe sufficiently fulfilled subsurface drainage capacity of 30mm/day. This paper was made by the support of Rural Development Administration (Research Project No. PJ01281503).

패킷 손실 환경에서 무기준법을 이용한 H.264/AVC 비디오의 객관적 영상품질 평가지표

김현태(Hyuntai Kim),김요한(Yohan Kim),윤지선(Jisun Yoon),신지태(Jitae Shin) 한국정보과학회 2011 정보과학회논문지 : 정보통신 Vol.38 No.3

보다 나은 영상서비스를 위해 부호화된 영상의 수신시 품질을 평가하는 방법이 중요한 요소중에 하나이다. 본 연구는 객관적 영상 품질 평가방법 중에서 실시간 화질 평가에 적합한 무기준법으로 복잡도가 적으면서도 정확도가 높으며 주관적 화질을 반영하는 H.264/AVC 영상에 적용한 무기준법 화질평가를 제안한다. 제안하는 무기준법 화질평가 방법은 양자화 파라미터와 움직임 벡터 정보, 패킷 손실의 위치, 손실의 패턴, GOP 크기를 이용하여 부호화 과정의 화질열화와 전송과정에서의 패킷 손실에 따른 화질 열화를 고려하여 측정하였으며 사람의 인지적인 품질을 반영하기 위한 주관적 화질평가(DMOS)와의 상관관계를 사용하여 기존방법과 비교하여 성능을 검증하였다. Objective video-quality assessment method is one of essential components to indicate better user-quality. This work proposes a video-quality metric with no-reference method for encoded H.264/AVC that offers less complexity and higher accuracy and that is well-matched with subjective video quality. The proposed quality metric uses the bitstream information such as quantization parameters, motion vectors, locations and patterns of packet loss, and the Group of Picture (GOP) size. The proposed one includes two parts: the encoding distortion and the transmission distortion. The encoding distortion is from lossy encoding and the transmission distortion from the error propagation properties with packet loss. The performance of the proposed metric outperforms the existing schemes in terms of the correlation with subjective Differential Mean-Opinion-Score (DMOS) which reflects the human perception quality.

밭작물 논 재배 확대를 위한 무굴착 암거배수 기술 개발

김현태 ( Hyuntai Kim ),정기열 ( Kiyuol Jung ),이상훈 ( Sanghun Lee ),유전용 ( Jeonyong Ryu ) 한국농공학회 2017 한국농공학회 학술대회초록집 Vol.2017 No.-

농업환경변화를 보면 농가소득이 벼보다 밭작물이 높기 때문에 기존 논에서 밭 작물재배를 원하는 농가가 많다. 하지만 저습답은 지하수위와 함수비가 높아 작물이 습해를 입기 때문에 밭작물재배에 어려움이 많다. 저습답에서 밭작물재배를 위하여, 지하암거와 심토파쇄 등의 보조공법이 적용되고 있으나, 기존 공법은 공사비가 높고, 지하배수효과가 낮은 문제가 있어, 저습답 농지범용화를 위하여 저비용 고효율 지하암거공법의 개발·도입이 필요하다. 본 연구에서 무굴착으로 시공이 가능한 암거모양별 지하배수성능을 분석하고, 공사비를 비교하여, 저비용 고효율 무굴착 지하암거공법을 제안하고, 저습답에 시험시공을 통하여 다음과 같은 결론을 얻었다. ① 무굴착시공이 가능한 ⓐ 유공관암거, ⓑ 유공관+수평필터매트(폭50cm) 암거는 단위m당 배수량은 기존 ⓒ 유공관+자갈소수재(30^*40cm)암거의 ⓐ 54%, ⓑ 92%로 적으나, m당공사비가 1/3로 기존암거를 10m간격으로 설치하는 것보다 ⓑ 유공관+수평매트암거를 5m간격으로 설치하면 공사비는 70%이나, 배수효과는 175%로 저비용 고효율 지하암거공법으로 평가·제안되었다. ② 이 결과를 바탕으로 미사질양토 저습답에 지하암거 시험시공결과, ⓒ 기존공법(7m간격)보다 ⓑ 무굴착 유공관+수평필터매트 암거(3, 5m간격)가 공사비도 적으면서, 지하수위 상승이 훨씬 적고, 하강도 훨씬 빠른 결과를 보이고 있다. ③ 토양함수비도 ⓒ 기존공법(7m간격)보다 ⓑ 무굴착 암거(3, 5m간격)가 함수비 상승도 적으면서 빠르게 작물생육의 최적함수비 상태로 되는, 훨씬 좋은 결과를 보였다. ④ 콩 시험재배결과 무암거 경구보다 기존 암거공법과 무굴착 암거설치경구가 작황이 훨씬 좋은 것으로 볼 때, 공사비가 저렴한 ⓑ 무굴착암거공법이 저습답 농지범용화에 적용이 가능한 저비용 고효율 공법으로 확인되었다. ⑤ 그리고 100^*100m의 대구획의 저습답은 규모화와 범용화 영농의 큰 장점을 가지고 있으나, 경사가 거의 없는 평지로 집중강우 시 포장 내 지표배수가 잘되지 않아, 이를 해결하기 위한 연구도 함께 필요하다는 결론을 얻었다.

AIIB Development: Forecast and Implications

LEE Hyuntai,KIM Junyoung 대외경제정책연구원 2016 World Economy Brief Vol.2016 No.01