두 개의 이중 모드 공진기를 이용한 소형 이중 대역 통과 필터

김경근(Kyoungkeun Kim),이자현(Jahyeon Lee),임영석(Yeongseog Lim) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.12

본 논문에서는 두 개의 이중 모드 공진기를 이용하여 이중 대역 통과 필터를 구현하였다. 단락 스터브를 이용한 이중 모드 공진기는 inter-digital 커패시터와 계단형 임피던스를 이용하여 소형화 되었다. 두 개의 이중 모드 공진기는 각 통과 대역의 중심 주파수에서 동작하도록 설계되었다. 전송 영점이 통과 대역의 상측이나 하측에 위치하여 차단 특성을 향상시킬 수 있다. 이중 대역 동작을 위해 이중 급전 구조를 이용하였다. 제안된 구조는 WLAN 대역인 2.45/5.25 ㎓에서 동작하도록 설계?제작되었다. 제안된 이중 대역 통과 필터의 크기는 10.83 ㎜×5.3 ㎜이다. In this paper, the design and the fabrication of dual-band bandpass filter using two dual-mode resonators is presented. Dual-mode resonator using a short stub is miniaturized by inter-digital capacitor and stepped impedance. Two dual mode resonators are designed to have different resonant frequencies, one for the lower passband and the other for the upper passband. Transmission zero is positioned at low or high rejection bands with a sharp skirt characteristic. Dual-band operation can be achieved using dual feeding structure. For WLAN, the proposed filter at 2.45/5.25 ㎓ is designed and fabricated. The size of the filter is as compact as 10.83 ㎜×5.3 ㎜.

유방 보존술 후 내유림프절을 포함하는 방사선치료 기법에 관한 연구

정경근(Kyoungkeun Jeong),심수정(Su Jung Shim),유세환(Sei Hwan You),김용배(Yong Bae Kim),금기창(Ki Chang Keum),김종대(Jong Dae Kim),서창옥(Chang Ok Suh) 대한방사선종양학회 2009 Radiation Oncology Journal Vol.27 No.1

목 적: 유방암 환자에서 부분적 유방절제술 후 내유림프절(internal mammary lymph node: IMN)을 포함하여 방사선 치료하기 위한 최적의 치료 방법을 찾고자 하였다. 대상 및 방법: 초기 유방암으로 부분적 유방절제수술을 받고 방사선치료를 받은 10명의 환자들의 CT simulation 데이터를 얻어서 각 환자들에서 4가지 치료방법을 계획하고 평가하였다. 5명은 오른쪽 유방을, 나머지 5명은 왼쪽 유방을 치료 받았다. 각 환자에서 유방, 쇄골 상부 림프절(supraclavicular lymph node: SCL), IMN (위쪽 3개의 늑골사이에 있는 림프절만 포함)을 조사하는 치료계획을 하였다. IMN을 조사하는 방법으로 4가지 방식, 즉 표준적인 접선방향 치료(Standard Tangential Field: STF), 확장접선치료 방법(Wide Tangential Field, WTF), 부분 확장접선치료방법(Partially Wide Tangential Field: PWT), 광자와 전자를 혼합한 방법(Photon-Electron Mixed 5 Field: PEM)을 사용하였다. SCL field는 3 cm에, 유방조직은 중심점에 50.4 Gy를 28회에 나누어 치료하도록 처방하였다. 결 과: 각각의 치료 기법은 환자마다 차이는 있었으나 뚜렷한 특징을 보였다. 유방조직의 선량은 각 치료 기법마다큰 차이가 없었다. IMN는 치료 기법마다 차이가 있으나 STF를 제외한 세 가지 방법은 대체로 IMN을 잘 감싸고 있었다. 왼쪽 유방을 치료하는 경우 심장이 받는 선량은 고선량 영역에서는 WTF, PWT, PEM, STF의 순으로 많은 체적에 선량을 받았으며 낮은 선량 영역에서는 PEM, WTF, PWT, STF의 순이었다. 동측 폐의 선량 역시 마찬가지의 순서를 보였다. Lyman-Kutcher-Burman model에 의한 방사선 폐렴에 대한 NTCP는 개인별 편차가 컸다. 대체로STF가 가장 작고 PWT가 다음이었으나 PEM와 WTF의 경우는 환자마다 큰 차이를 보였다. 결 론: 환자들의 다양한 체형에도 불구하고 IMN를 포함하여 치료하는 경우 PWT가 폐와 심장의 조사선량을 줄이고 IMN에 표적선량을 전달하는데 적합한 것으로 생각된다. Purpose: This study was designed to determine the optimum radiotherapy technique for internal mammary node (IMN) irradiation after breast-conserving surgery. Materials and Methods: We selected ten cases of early stage partial mastectomy for plan comparison. Five of the patients were treated to the right-side breast and the rest of the patients were treated to the left-side breast. For each case, four different treatment plans were made to irradiate the entire breast, IMNs and supraclavicular lymph nodes (SCLs). The four planning techniques include a standard tangential field (STF), wide tangential field (WTF), partially wide tangential field (PWT) and a photon-electron mixed field (PEM). We prescribed a dose of 50.4 Gy to the SCL field at a 3 cm depth and isocenter of the breast field. Results: The dose distribution showed clear characteristics depending on the technique used. All of the techniques covered the breast tissue well. IMN coverage was also good, except for the STF, which was not intended to cover IMNs. For the cases of the left-side breasts, the volume of the heart that received more than 30 Gy was larger (in order) for the WTF, PWT, PEM and STF. For radiation pneumonitis normal tissue complication probability (NTCP), the PWT showed the best results followed by the STF. Conclusion: Despite the variety of patient body shapes, the PWT technique showed the best results for coverage of IMNs and for reducing the lung and heart dose.

Preparation of Nano-Sized Tin Oxide Powder from Waste Pb-Free Solder by Direct Nitric Acid Leaching

Yoo, Kyoungkeun,Lee, Kwangseok,Jha, Manis Kumar,Lee, Jae-Chun,Cho, Kuk American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.11

<P>Nano-sized tin oxide particles were prepared by nitric acid (HNO3) leaching of Pb-free solder containing tin (Sn), silver (Ag), and copper (Cu) as main components. During the nitric acid leaching, Ag and Cu were dissolved whereas Sn was not detected in the leach solution and the leaching efficiencies of Ag and Cu increased with increasing temperature and HNO3 concentration. The precipitates were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). The tin precipitate was determined to be tin oxide by XRD and nano-sized particles were observed in the SEM and TEM images. The larger particle size was observed in the leaching condition of slow leaching rate. The purity and particle size of tin precipitate, obtained from the leaching test performed in the 2 mol/L HNO3 solution at 90 degrees C and 400 rpm, were 99.986% and 6.03 nm, respectively.</P>

이종 공진기를 이용한 이중 대역 통과 필터

김경근(Kyoungkeun Kim),임영석(Yeongseog Lim) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.3

본 논문에서는 서로 다른 공진점을 갖는 공진기들을 이용하여 이중 대역 통과 필터를 구현하였다. 서로 다른 공진점을 갖는 λg/2 공진기들을 이용하여 각 공진기들의 동작 주파수가 서로의 동작 주파수에 영향을 미치지 않는 것을 이용하여 이중 대역 통과 필터를 설계하였다. 하측 통과 대역은 λg/2 공진기와 λg/4 공진기를 이용하였고, 상측 통과 대역은 이중 모드 공진기를 이용하여 설계하였으며, 하측 통과 대역의 공진기는 상측 통과 대역의 급전부로 동작한다. 제안된 구조는 WLAN 대역인 2.45/5.2 ㎓와 2.45/5.8 ㎓에서 동작하도록 설계 제작되었다. In this paper, the design and the fabrication of dual bandpass filter using heterogeneous resonators is presented. Each resonator would not have an effect on each resonant frequency. Two types of resonators are designed to have different fundamental resonant frequencies, one for the lower passband and the other for the upper passband. In the lower band, half and quarter wavelength resonators were used. In the upper band, a dual-mode resonator was used for adjusting bandwidth. In the upper pass band frequency, resonators of lower passband acts as the input and output. For WLAN, Proposed filters with different second passband frequencies at 2.45/5.2 ㎓ and 2.45/5.8 ㎓ are designed and fabricated.

Dissolution of Magnesium from Serpentine Mineral in Sulfuric Acid Solution

Yoo, Kyoungkeun,Kim, Byung-Su,Kim, Min-Seuk,Lee, Jae-chun,Jeong, Jinki The Japan Institute of Metals 2009 MATERIALS TRANSACTIONS Vol.50 No.5

<P>As the volume of CO<SUB>2</SUB>, one of greenhouse gases linked to global warming, in the atmosphere increases, there has been an increasing interest in CO<SUB>2</SUB> sequestration. Aqueous carbonation, which involves the extraction of Mg from serpentine minerals and the subsequent carbonation reaction with CO<SUB>2</SUB> to form the geologically stable mineral MgCO<SUB>3</SUB>, has been proposed as a promising CO<SUB>2</SUB> sequestration technology. This study investigates the dissolution of Mg from serpentine mineral in H<SUB>2</SUB>SO<SUB>4</SUB> solution. The study is part of a major research project aimed at developing an effective CO<SUB>2</SUB> sequestration technology using the serpentine mineral which is readily available in Korea. Complete dissolution of Mg from natural serpentine was achieved in 30 min at a temperature of 90°C under 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB>. The rate of dissolution of Mg was independent of the agitation speed at speeds above 300 rpm. The fraction of Mg dissolved from milled serpentine was found to be a little higher than that from natural serpentine up to 70°C in 0.5 M H<SUB>2</SUB>SO<SUB>4</SUB>. The Jander equation was used to explain the dissolution rate data. The rate of Mg dissolution seemed to be limited by diffusion through the thin channels formed between the silica layers in the serpentine particles.</P>

A Comparative Planning Study of Step-and-shoot IMRT versus Helical Tomotherapy in a Model Patient

김용남,김수곤,Kyoungkeun Jeong,이창걸,금기창,이익재,조재호 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7

In order to assess the potential benefit of being able to use non-coplanar beams in a step-andshootintensity-modulated radiotherapy (ssIMRT) differently from helical tomotherapy (HT), weperformed a comparative planning evaluation in a model patient whose clinical target volumesenclosed critical normal tissue lying in the same plane. A patient with extensively relapsed malignantlymphoma in the circumferential chest wall was selected for comparison. Multiple, separated grosstumors were delineated, and the clinical target volume included the circumferential chest wallcontaining gross tumor volumes so that the critical organ, the right lung was fully enclosed. Threetypes of plans were analyzed; the first one was ssIMRT using only coplanar beams, the second wasssIMRT using non-coplanar beams, and the third was HT. The obtained results showed that dosehomogeneity inside the gross tumor volume was better in the case of HT than noncoplanar ssIMRTand coplanar ssIMRT. However, the volume fraction of the right lung receiving a high dose wasmuch smaller in the noncoplanar ssIMRT. As far as the dose to the clinical target volume (CTV)fully enclosing the right lung is concerned, not only the dose coverage of the CTV but also the dosehomogeneity and conformity in the noncoplanar ssIMRT was better than in both of HT and thecoplanar ssIMRT. We can conclude that appropriate isodose coverage for a complex target, whichfully encloses a critical organ lying in the same plane, can be achieved by using a non-coplanarbeam arrangement with no enforced penalty of higher dose to a critical organ.

Hydrochloric acid leaching behavior of metals from non-magnetic fraction of Pb dross

Sanghyeon Choi,Kyoungkeun Yoo,Richard Diaz Alorro 한국자원공학회 2019 Geosystem engineering Vol.22 No.6

The leaching behaviors of tin (Sn), antimony (Sb), iron (Fe), and lead (Pb) from non-magnetic fraction of Pb dross, which was obtained from magnetic separation process to remove As components, were investigated using HCl solution. The leaching efficiencies of Sn, Fe, and Pb increased with increasing agitation speed, temperature, and HCl concentration and with decreasing pulp density, but Sb was dissolved only in the 3 and 5 M HCl solutions. The leaching efficiencies of metals increased to 100% in the 5 M HCl solution at 400 rpm and 70°C with 1% pulp density within 120 min. In the case of leaching test with 1 M HCl, Sb components could be recovered as leach residue. After leaching test, Pb could be recovered as PbCl2 from the solution by lowering temperature. Tin ions were extracted selectively by solvent extraction with tri-butyl phosphate, remaining Fe and Pb ions in the solution. The process consisting of HCl leaching, precipitation, and solvent extraction recovers successfully Sb, Pb, and Sn from non-magnetic fraction of Pb dross.

자율주행차 제어권전환 평가 시나리오 구성을 위한 국내 고속도로 실사고 영상분석 연구(1)

박요한(Yohan Park),조경근(Kyoungkeun Cho),인용현(Yonghyun In) 대한인간공학회 2017 대한인간공학회 학술대회논문집 Vol.2017 No.11

제어 가능한 전송 영점을 갖는 CRLH 전송 선로

이자현(Jahyeon Lee),김경근(Kyoungkeun Kim),임영석(Yeongseog Lim) 한국전자파학회 2010 한국전자파학회논문지 Vol.21 No.6

본 논문에서는 제어 가능한 전송 영점을 갖는 새로운 Composite Right/Left Handed(CRLH) 전송 선로가 제안 되었다. 제안된 CRLH 전송 선로의 단위 셀은 MIM 형태의 커패시터와 마이크로스트립 스터브 인덕터와 co-planar waveguide(CPW) 인덕터로 구성되어 있다. 또한 제안된 전송 선로는 각각의 단위 셀의 MIM 커패시터와 마이크로스트립 스터브 인덕터에서 발생하는 전자기 결합 성분에 의해 차단 대역에 두 개의 전송 영점이 발생한다. 제안된 전송 영점을 갖는 CRLH 전송 선로의 응용으로 UWB 시스템을 위한 광대역 통과 필터를 설계 및 제작하였다. 측정 결과, 통과 대역의 하측과 상측에 전송 영점이 발생하는 것을 확인하였으며, 대역 통과 필터의 급전 구조를 제외한 크기는 8 ㎜×8 ㎜으로 λg/4 이하의 전기적 크기를 갖는다. In this paper, a novel CRLH-TL unit cell with controllable transmission zeros was proposed. Proposed composite right/left handed transmission line(CRLH-TL) unit cell is implemented in the form of the metal-insulator-metal(MIM) capacitors, the microstrip stub inductors, and the co-planar waveguide(CPW) inductor. And this proposed CRLH-TL generates two transmission zeros in lower/upper passband by the effort of electromagnetic couplings between each MIM capacitors and microstrip stub inductors. Using this proposed CRLH-TL, broad bandpass filter for UWB system was designed and fabricated. The measured results reveal that the two transmission zeros are observed in lower/upper passband and the overall size of the filter, excluding the feed line is about 8 ㎜×8 ㎜, less then λg/4 on electric size.

암모니아 침출공정(浸出工程) 기술개발(技術開發) 동향(動向)

유경근,김현중,Yoo, Kyoungkeun,Kim, Hyunjung 한국자원리싸이클링학회 2012 資源 리싸이클링 Vol.21 No.5

암모니아 습식제련공정은 철과 칼슘의 용해를 억제하며 구리 등의 금속을 선택적으로 침출이 가능한 장점이 있어 구리, 금, 니켈 및 코발트 등의 금속을 선택적으로 침출하기 위한 연구가 수행되어왔다. 이 글에서는 모터스크랩과 폐인쇄회로기판으로부터 구리의 선택적 침출, 티오황산염 사용 등 시안의 대체 및 저감을 위한 금의 암모니아침출, 산화니켈광 및 망간단괴처리공정 중간산물로부터 니켈과 코발트를 회수하기 위한 암모니아침출 기술개발동향을 정리하고 국내 연구개발방향을 제시하고자 하였다. Selective leaching processes for copper, gold, nickel, and cobalt have been investigated because there is an advantage of ammoniacal hydrometallurgy that metal such as copper could be selectively extracted restricting the dissolution of iron or calcium. In the present article, the studies for selective ammoniacal leaching of copper from motor scraps and waste printed circuit boards (PCBs), for ammoniacal leaching of gold to decrease the amount of cyanide used or to substitute cyanide by thiosulfate, and for ammoniacal leaching to recover nickel and cobalt from nickel oxide ore and intermidiate obtained from manganese nodule treatment process were summarized and further studies were proposed for domestic technology development for ammoniacal hydrometallurgy processes.