In_xGa_1-xN/GaN 다중양자우물 구조의 광학적 성질 연구

김기홍,김인수,박헌보,배인호,유재인,장윤석,Kim, Ki-Hong,Kim, In-Su,Park, Hun-Bo,Bae, In-Ho,Yu, jae-In,Jang, Yoon-Seok 한국진공학회 2009 Applied Science and Convergence Technology Vol.18 No.1

$In_xGa_{1-x}N$/GaN 다중양자우물 구조의 EL 특성을 온도와 주입전류 변화에 따른 특성을 조사하였다 저전류와 고전류 주입시 EL 효율의 온도 의존 변화는 매우 다르게 나타나는데, 이러한 온도와 전류의 변화에 의한 독특한 EL 효율의 변화는 내부전기장의 존재 하에 순방향 바이어스에 기인한 외부전기장의 영향인 것으로 볼 수 있다. 그리고 $In_xGa_{1-x}N$/GaN 다중양자우물 구조에서 In 성비의 증가는 발광파장위치의 적색이동을 보였다. 15K에서 주입 전류의 증가에 따라 녹색 양자우물 구조는 80 meV와 청색 양자우물 구조는 22 meV의 청색 편이를 하였다. 이는 전류의 증가에 의해 단위 시간당 생성되는 캐리어 수가증가하게 되고 그에 따라 subband가 급격히 채워지는 band filling 현상이 일어나게 되어 짧은 파장에서 재결합이 증가하기 때문이다. 그리고 청색과 녹색 다중 양자우물구조의 짧은 파장 쪽으로의 편이 차이는 In 농도에 기인한 것으로 In 농도가 높으면 양자우물 깊이가 증가되어 더 강한 양자속박효과가 작용하여 캐리어 구속력이 증가하기 때문 것으로 볼 수 있다. Temperature and injection current dependence of electroluminescence(EL) spectral intensity of the $In_xGa_{1-x}N$/GaN multi-quantum wells(MQW) have been studied over a wide temperature range and as a function of injection current level. It is found that a temperature-dependent variation pattern of the EL efficiency under very low and high injection currents shows a drastic difference. This unique EL efficiency variation pattern with temperature and current can be explained field effects due to the driving forward bias in presence of internal(piezo and spontaneous polarization) fields. Increase of the indium content in $In_xGa_{1-x}N$/GaN multiple quantum wells gives rise to a redshift of 80 meV and 22 meV for green and blue MQW, respectively. It can be explained by carrier localization by potential fluctuation of multiple quantum well and MQW structures also shows a keen difference owing to the different indium content in InGaN/GaN MQW.

Brake-By-Wire system을 위한 Electro-Mechanical Brake 설계

김인수(In Su Kim),김만호(Man Ho Kim),이석(Suk Lee),이경창(Kyung Chang Lee) 한국자동차공학회 2006 한국자동차공학회 Symposium Vol.- No.-

In order to implement various intelligent functions and to reduce weight and required space, automobile industry now apply by-wire teehnology to many critical subsystems of a car. One of These attempts is brake-by-wire system where the traditional hydraulic mechanism is replaced by electro-mechanical brake(EMB) and in-vehicle network. Especially in case of brake-by-wire system, simplicity is important factor. This paper presents an EMB design for low-speed electric vehicle such as golf cart and comparing two electro-mechanical brake(EMB) using lead screw and ball serew.

Electro-Mechanical Brake의 제동 압력 제어

김인수(In Su Kim),김만호(Man Ho Kim),이석(Suk Lee),이경창(Kyung Chang Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

In order to implement various intelligent functions and to reduce weight and required space, automobile industry now apply by-wire technology to many critical subsystems of a car. One of these attempts is brake-by-wire system where the traditional hydraulic mechanism is replaced by electro-mechanical brake(EMB) and in-vehicle network. Especially in case of brake-by-wire system, simplicity and efficiency are important factor. This paper presents an comparison between lead screw and ball screw and error squared PI controller.

과산화수소를 이용한 현장원위치 화학적 산화법과 공기분사법(Air-sparging)을 연계한 디젤 오염 토양/지하수 동시 정화 실내 실험 연구

김남호,김인수,최애정,이민희,Kim, Nam-Ho,Kim, In-Su,Choi, Ae-Jung,Lee, Min-Hee 한국지하수토양환경학회 2006 지하수토양환경 Vol.11 No.6

현장비원위치(Ex-situ) 공법 적용이 불가능한 부지에서, 디젤로 오염된 오염 토양과 지하수를 동시에 복원하기 위하여 과산화수소를 이용한 현장원위치 화학적 산화법(chemical oxidation)과 공기분사법(air-sparging)을 연계한 복합 복원 공정의 정화 효율 규명을 위한 실내 실험을 실시하였다. TPH 농도가 2,401 mg/kg(A 토양)과 9,551 mg/kg(B 토양)인 두 종류의 현장 오염 토양을 대상으로 과산화수소용액을 이용한 화학적 산화법의 디젤 제거 효율 규명을 위한 배치(회분식) 실험 결과, 과산화수소 50% 용액에 의해 토양 초기 TPH 농도의 18%와 15%까지 감소하였다. 과산화수소 용액 20%를 이용한 칼럼 세정 실험 결과, 세정에 의해서 A 토양과 B 토양의 경우 각각 초기 TPH 양의 78%와 72%가 제거되었다. 칼럼 실험에서 과산화수소의 산화반응에 의해 완전 분해되어 무기가스상(주로 $CO_2$과 $H_2O$)으로 제거된 양까지 고려한다면, 과산화수소용액이 오염 토양과 접촉하면서 충분한 산화과정을 거쳐 대부분의 유류가 토양으로부터 제거되었음을 알 수 있었다. 공기분사법을 이용한 디젤 오염 지하수 정화 실험의 경우, TPH 농도가 820 mg/L인 고농도의 인공 지하수 경우에도 공기분사 72시간 이내에 폐수배출허용기준인 5 mg/L 보다 낮아져, 디젤 제거 효율이 매우 높은 것으로 나타났다. 다만, 오염 토양 내 다량의 디젤 자유상이 존재하는 경우 토양으로부터 지하수로의 지속적인 자유상 디젤의 질량 이동에 의하여, 공기분사법의 지하수 정화 효율은 매우 낮았다. 마지막으로, 과산화수소를 이용한 현장원위치 화학적 산화법과 공기분사법을 연계한 복합 공정의 디젤 정화 효율을 규명하는 박스 실험을 실시하였다. 토양 내 자유상 디젤을 먼저 제거하기 위해 과산화수소 용액을 이용한 토양세정법을 실시한 후, 토양 내 TPH가 제거 되는 정도에 따라 후차적으로 공기분사법을 적용함으로써 토양 및 지하수로부터 디젤을 효과적으로 제거할 수 있었다. 20% 과산화수소 용액의 23 L 세정과 2,160 L의 공기분사에 의해 토양의 TPH 농도는 9,551 mg/kg에서 390 mg/kg으로 낮아졌으며, 오염 지하수의 TPH 농도도 5 mg/L 이하로 낮출 수 있었다. 본 실험들에서 얻어진 결과를 바탕으로 실제 현장에서 대단위 공정을 운영하는데 필요한 복원 공정의 최적 조건들을 도출해 낼 수 있으리라 판단되며, 유류로 오염된 토양 뿐 아니라 오염 지하수까지 동시에 정화할 수 있는 복합 공정 개발을 위한 중요한 기술 자료로 이용될 수 있을 것으로 판단된다. Laboratory scale experiments were performed to investigate the removal efficiency of the in-situ chemical oxidation method and the air-sparging method for diesel contaminated soil and groundwater. Two kinds of diesel contaminated soils (TPH concentration : 2,401 mg/kg and 9,551 mg/kg) and groundwater sampled at Busan railroad station were used for the experiments. For batch experiments of chemical oxidation by using 50% hydrogen peroxide solution, TPH concentration of soil decreased to 18% and 15% of initial TPH concentration. For continuous column experiments, more than 70% of initial TPH in soil was removed by using soil flushing with 20% hydrogen peroxide solution, suggesting that most of diesel in soil reacted with hydrogen peroxide and degraded into $CO_2$ or $H_2O$ gases. Batch experiment for the air-sparging method with artificially contaminated groundwater (TPH concentration : 810 mg/L) was performed to evaluate the removal efficiency of the air-sparging method and TPH concentration of groundwater decreased to lower than 5 mg/L (waste water discharge tolerance limit) within 72 hours of air-sparging. For box experiment with diesel contaminated real soil and groundwater, the removal efficiency of air-sparging was very low because of the residual diesel phase existed in soil medium, suggesting that the air-sparging method should be applied to remediate groundwater after the free phase of diesel in soil medium was removed. For the last time, the in-situ box experiment for a unit process mixed the chemical oxidation process with the air-sparging process was performed to remove diesel from soil and groundwater at a time. Soil flushing with 20% hydrogen peroxide solution was applied to diesel contaminated soils in box, and subsequently contaminated groundwater was purified by the air-sparging method. With 23 L of 20% hydrogen peroxide solution and 2,160 L of air-sparging, TPH concentration of soil decreased from 9,551 mg/kg to 390 mg/kg and TPH concentration of groundwater reduced to lower than 5 mg/L. Results suggested that the combination process of the in-situ hydrogen peroxide flushing and the air-sparging has a great possibility to simultaneously remediate fuel contaminated soil and groundwater.

분자선 에피탁시법으로 성장된 Al0.25Ga0.75As / In0.15Ga0.85As / GaAs 슈우도형 고 전자 이동도 트랜지스터 구조의 광학적 특성

이동율(Dong-Yul Lee),이철욱(Chul-Wook Lee),김기홍(Ki-Hong Kim),김종수(Jong-Su Kim),김동렬(Dong-Lyeul Kim),배인호(In-Ho Bae),전헌무(Hunmoo Jeon),김인수(In-Soo Kim) 한국진공학회(ASCT) 2000 Applied Science and Convergence Technology Vol.9 No.2

Photoluminescence(PL)와 photoreflectance(PR}를 이용하여 Al_(0.25)Ga_(0.75)As/In_(0.15)Ga_(0.85)As/GaAs 슈우도형 고 전자 이동도 트랜지스터 구조에 대한 특성을 조사 하였다. 온도 10 K의 PL 측정에서 InGaAs 양자우물에 의한 e2-h1 및 e2-h1 전이 피크가 각각 1.322 및 1.397 eV에서 관측되었다. 온도 의존성으로부터 첫번째 가전자 띠와 두번째 가전자 띠의 에너지 차이는 약 23 meV로 나타났다. 또한 300 K에서의 PR 측정으로 e2-h2 및 e2-h1 전이에 의한 피크를 관측하였고, 두번째 전도 띠의 에너지 준위에 의한 피크가 띠 채움으로 인해 첫번째 전도 띠의 에너지 준위에 의한 피크보다 상대적으로 우세하였다. 반면에 PL 측정에서는 전자 가리개 효과 때문에 첫번째 전도 띠에 의한 피크가 우세하였다. We have analyzed characteristics for the structure of Al_(0.25)Ga_(0.75)As / In_(0.15)Ga_(0.85)As/GaAs pseudo-morphic high electron mobility transistor (PHEMT) by photoluminescence (PL) and photoreflectance (PR) measurements. By the PL measurement at 10 K, we observed e1-h1 transition peak at 1.322 eV and e2-h1 transition peak at 1.397 eV in the InGaAs quantum well. We calculated value of 23 meV, the difference between the first energy level and the second energy level of a valence band by dependence of temperatures. Also, (e2-h2) transition signal was observed at 300 K by PR measurement. From the PR measurement, we recognized that the transition was dominated the second energy level of conduction band than the first energy level of conduction band due to band filling. The other hand, PL signal of the first energy level of conduction band was dominated because of the electron screening effect.

IN738LC 합금의 열간 노출 및 재생 열처리에 따른 미세조직과 응력 파단 특성의 변화

최백규,주동원,김인수,장중철,조창용,Choe, Baek-Gyu,Ju, Dong-Won,Kim, In-Su,Jang, Jung-Cheol,Jo, Chang-Yong 한국재료학회 2001 한국재료학회지 Vol.11 No.11

Effects of thermal exposure and rejuvenation treatment on the microstructural evolution and the stress-rupture properties of IN738LC have been investigated. The role of precipitates on the stress-rupture properties has been analyzed through microstructural observations. Thermal exposure at $982^{\circ}C$ for 1000 hours gave rise to precipitation of $\sigma$ phase and coarsening of r'. The microstructural degradation with thermal exposure at $982^{\circ}C$ deteriorated stress rupture properties of the alloy. All the existing phases except MC carbides have completely dissolved into the matrix with homogenization treatment at $1200^{\circ}C$ for 2 hours. Microstructure and stress-rupture properties of the thermal exposed specimens have been successfully rejuvenated by the proposed treatment.

교수설계요소로서 환상(Fantasy)의 구성요소와 구현원리에 대한 연구

김인수 ( In Su Kim ) 한국교육정보미디어학회 2009 교육정보미디어연구 Vol.15 No.4

환상은 인간의 의식을 그 물리적 존재에 한정하지 않고 현실세계를 초월한 곳으로 확대시켜 주는 특성을 가지며 이러한 특성 때문에 고대로부터 현대에 이르기까지 인간의 문화적 생활과 불가분의 관계를 가져왔다. 특히 현대에 와서는 공학적 발달을 배경으로 문학이나 영상 등 환상적 요소를 담은 문화상품들이 전 세계적으로 성공을 거두고 있고 또 그 잠재가능성이 특정 분야에 한정되지 않는 것으로 인식됨에 따라 다양한 분야에서 환상에 대한 관심이 그 어느 때 보다 고조되고 있다. 이러한 추세는 교육 분야도 예외가 아니다. 환상적 요소는 교육에 흥미와 역동성을 제공함으로써 학습효과를 증진시키는 것으로 평가되어 교육환경의 구성, 학습교재의 제작 등 교육실천의 분야에서 환상과 환상성을 활용한 구체적 사례들을 생성해 내고 있고 또 큰 성공을 거두는 경우도 빈발하고 있다. 그러나 교육의 실천적 영역에서 활발히 사용되고 있음에도 불구하고 환상에 대한 연구는 상대적으로 활발하지 않으며, 특히 교육적 상황에서 활용하고자 할 때 적용할 수 있는 처방적 원리는 찾아보기 어렵다. 본 연구의 목적은 지식과 환상을 결합시켜 교육 콘텐츠를 설계하고자 할 때 활용할 수 있는 환상의 구성요소와 구현의 원리를 탐구하는 것이다. 본 연구는 연구목적을 달성하기 위해 여러 분야에서 제시하는 환상에 대한 논의를 고찰하고 환상적 요소를 위주로 교육 콘텐츠를 설계하는 전문가 7인을 대상으로 심층면담을 실시하였다. 본 연구의 결과는 다음과 같다. 첫째, 환상의 구성요소는 시각적 요소, 통찰적 요소, 심리적 요소로 범주화되었다. 이 세 가지 범주는 환상적 시공간, 환상적 존재, 발생적 통찰, 가치적 통찰, 새로움, 친근감의 여섯 가지 하위 요소를 포함한다. 둘째, 환상의 구현원리는 왜곡적 재현, 구체적 재현, 실제적 재현, 조합적 재현의 넷으로 범주화하여 제시되었다. 이는 존재의 왜곡, 시공간의 왜곡, 소재의 왜곡, 추상적 개념의 공간화, 추상적 개념의 존재화, 체험적 실제, 묘사적 실제, 은닉성, 이야기성, 정합성 등 열 가지 구현원리를 그 내용으로 한다. The purpose of this study is to explorer what factors and principles that fantasy applies to the educational context. For this purpose, in-depth interview was conducted. In conclusion, firstly, this study identified six factors(fantastic space/time, fantastic being, insight into origin, insight into value, novelty, affinity) with three categories. Secondly, this study explored ten principles (distortion of being, distortion of time and space, distortion of material, embodiment of an abstract idea to fantastic space, embodiment of an abstract idea to fantastic being, physical experience of fantastic events, descriptive experience of fantastic events, concealment of learning purposes, storytelling, harmony with learning material and fantasy setting) with four categories. Based on the above, the study suggest three considerations for applying these principles to the educational content design. Specifically this study is likely to contribute by adding practical knowledge of educational factors that fantasy offers, and the way to represent them into educational application such as designing and developing educational contents.

부분공간법을 이용한 연속 냉간압연기의 상태공간모델 규명

김인수,황이철,이만형,Kim, In-Su,Hwang, Lee-Cheol,Lee, Man-Hyeong 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.2

In this paper, we study on the identification of discrete-time state-space model for robust control of tandem cold mill, using a MOESP(MIMO output-error state-space model identification) algorithm based on subspace method. It is shown that the identified model is well adapted to input-output data sets, which are obtained from nonlinear mathematical equations of tandem cold mill. Furthermore, deterministic H$\infty$ norm bounds on uncertainties including modeling errors and disturbances are quantitatively identified in the frequency domain. Finally, the results give a basic idea to determine weighting functions included in formulating some robust control problems of tandem cold mill.

黃連解毒湯, 黃連, 黃芩, 黃柏, 梔子의 Salmonella Typhimurium에 대한 항균효과

김인수,이영수,Kim, In-soo,Lee, Young-su 대한한방내과학회 2015 大韓韓方內科學會誌 Vol.36 No.2

Objectives: This experiment investigated the antimicrobial activity of Hwangryunheadok-tang and extracts of Scutellariae radix , Phellodendri cortex , Coptis rhizome , and Gardenia jasminoides against Salmonella typhimurium . Methods: After spreading S. typhimurium on a bacterial culture medium plate, antimicrobial activity was tested by dripping diluted Hwangryunheadok-tang or extracts of Scutellariae radix , Phellodendri cortex , Coptis rhizome , or Gardenia jasminoides (80 μl, diluted 100, 50, 10, and 1%) onto the plate, followed by culture for 16 to 72 hours. The minimal inhibitory concentration (MIC) was tested by dripping the minimum dilution that showed antimicrobial activity (80, 60, 40, and 20 μl) and measuring the density. The antimicrobial activity of Hwangryunheadok-tang and four extracts showed continuous antibacterial activity against S. typhimurium throughout the experiment. Result: 1. S. typhimurium . (Standard Microorganism, ATCC) 1) The Hwangryunheadok-tang and extracts of Scutellariae radix , Phellodendri cortex , and Coptis rhizome showed antibacterial activity in the undiluted solutions and in 50% dilutions. Gardenia jasminoides extract showed potency only in the undiluted solution. The antimicrobial potency of the undiluted solution was increased when the volume of inoculation was increased, but no difference was noted when the culture time was extended. All the extracts showed antimicrobial potency against S. typhimurium . 2. S. typhimurium isolated from diarrhea patients 1) When compared to the standard microorganism experiment on S. typhimurium , the MICs of the five extracts were increased. However, whereas the antimicrobial potency of doxycycline was lost entirely against bacteria isolated from patients with diarrhea, the antimicrobial potency of all the extracts was diminished but did not disappear. 2) The antimicrobial activity of Hwangryunheadok-tang and four extracts was continuous even when the culture time was extended to 16, 24, and 72 hours. Conclusions: The Hwangryunheadok-tang and four kinds of extracts have antimicrobial activity against S. typhimurium . Comparison of a standard microorganism with S. typhimurium isolated from diarrhea patients showed that the antimicrobial activity of all the extracts was better than that of antibiotics. Further studies should focus on the value and benefits of Hwangryunheadok-tang , and the four kinds of extracts as clinical treatments.

황련해독탕(黃連解毒湯), 황련(黃連), 황금(黃芩), 황백(黃柏), 치자(梔子)의 Staphylococcus aureus에 대한 항균효과

김인수,오현승,신민구,이영수,Kim, In-Soo,Oh, Hyun-Seung,Shin, Min-Koo,Lee, Young-Su 대한한방내과학회 2014 大韓韓方內科學會誌 Vol.35 No.4

Objectives: This experiment was done for investigating antimicrobial activity of Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, Gardenia Jasminoides extract against Staphylococcus aureus. Methods: After administering S. aureus on a bacterial culture media plate, antimicrobial activity was tested by dripping $80{\mu}l$ diluted Hwangryunheadok-tang and Scutellariae Radix extract, Phellodendri Cortex extract, Coptis Rhizoma extract, and Gardenia Jasminoides extract (100%, 50%, 10%, 1%) on plates that were cultivated for a span of time from 16 to 72 hours. Also, minimal inhibitory concentration (MIC) was tested by dripping the minimum dilution density solution that has antimicrobial activity between $80{\mu}l$ and $20{\mu}l$ ($80{\mu}l$, $60{\mu}l$, $40{\mu}l$, $20{\mu}l$) in measure of density. Antimicrobial activity of Hwangryunheadok-tang and four kinds of extracts against S. aureus was continually displayed. Results: 1. S. aureus (Standard Microorganism, ATCC) (1) Antimicrobial activity was displayed for Hwangryunheadok-tang, Scutellariae Radix extract, and Phellodendri Cortex extract respectively in the undiluted solution and 50% of diluted magnification. Gardenia Jasminoides extract showed its activity only in the undiluted solution; Coptis Rhizoma extract showed its activity down to 10% of diluted magnification. The antimicrobial activity of the undiluted solution was increased when the volume of inoculation increased. But, there was no difference when time was extended for cultivation. (2) MIC of Hwangryunheadok-tang, Scutellariae Radix extract was 50%, $20{\mu}l$. Coptis Rhizoma extract was 10%, $20{\mu}l$, Phellodendri Cortex extract was 50%, $80{\mu}l$ and Gardenia Jasminoides extract was 100%, $60{\mu}l$. 2. S. aureus isolated from diarrheal patients (1) When compared to standard microorganism, MIC has decreased. As a result, their antimicrobial activity has increased. (2) Antimicrobial activity of Hwangryunheadok-tang and four extracts was continually shown in extending of the time, 16, 24 and 72 hours. Conclusions: The author comes to the conclusion that Hwangryunheadok-tang, and four kinds of extracts have antimicrobial activity against S. aureus. Especially, when comparing standard microorganisms with S. aureus isolated from diarrheal patients, some cases showed that antimicrobial activity of all the extracts were better than antibiotics. Thus, if a further study is performed, the use of Hwangryunheadok-tang, and four kinds of extracts will be valuable and beneficial in clinical treatments.