RFCVD 장치를 이용하여 성장한 실리콘 나노와이어의 특성

김재훈,이형주,신석승,김기영,고춘수,김현숙,황용규,이충훈,Kim, Jae-Hoon,Lee, Hyung-Joo,Shin, Seok-Seung,Kim, Ki-Young,Go, Chun-Soo,Kim, Hyun-Suk,Hwang, Yong-Gyoo,Lee, Choong-Hun 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.2

We have synthesized silicon nanowires by using RFCVD(Radio Frequency Chemical Vapor Deposition) system on Au deposited p-type Si(100) wafers, and investigated their physical and electrical properties. The silicon nanowires had been grown in the atmospheres of $H_{2},\;N_{2}\;and\;SiH_{4}$ at 10 Torr at the substrate temperatures of $700{\pm}5^{\circ}C\;and\;810{\pm}5^{\circ}C$ respectively. FE-SEM analysis revealed that diameters of the silicon nanowires are $50{\sim}60nm$ with the length of several ${\mu}m$. XRD analysis showed that the growth direction of the nanowires is Si[111]. Field emission characteristics showed that the turn-of voltages at the current of $0.01\;mA/cm^{2}$ are $10\;V/{\mu}m\;and\;8.5\;V/{\mu}m$ for the wires grown at $700{\pm}5^{\circ}C\;and\;810{\pm}5^{\circ}C$, respectively.

건성안에서의 항산화 및 염증 억제 기능성 복합식품의 효과

김재훈,김호영,류양환,전연숙,유인천,윤경철,김재찬,Jae Hoon Kim,Ho Young Kim,Yang Hwan Ryu,Yeoun Sook Chun,In Cheon You,Kyoung Chul Yoon,Jae Chan Kim 대한안과학회 2008 대한안과학회지 Vol.49 No.9

Purpose: To evaluate the effect of Optibiol®, which is composed of multiple anti-oxidative and anti-inflammatory dietary elements, on the symptoms, clinical manifestations, and expression of various inflammatory cytokines in dry eye patients. Methods: Patients suffering from dry eye were given Optibiol® for 3 months. They completed questionnaires regarding dry eye symptom and underwent slit lamp biomicroscopic examinations, tear film breakup times, Shirmer tests, and conjunctival fluorescein staining examinations on a monthly basis during the intake of Optibiol®. Sampling of serum and tears was conducted at baseline and 3 months after taking Optibiol®, and various inflammatory cytokines in the serum and tears were measured with multiplex bead immunoassay. Result: Sixty-three patients were included in this study. After taking Optibiol®, the dry eye symptoms, Schirmer scores, tear film breakup times, and conjunctival staining scores (Oxford scale) showed significant improvement, and the expression of most inflammatory cytokines had decreased: in particular, IL-1β and MIP-1β in serum, and IL-17 and MIP-1β in tears were significantly lower. Conclusions: Optibiol®, an anti-oxidative and anti-inflammatory functional dietary supplement, is an effective dietary supplement in patients with dry eye syndrome. We posit that the decreased expression of inflammatory cytokines is an important mechanism in this effect. J Korean Ophthalmol Soc 2008;49(9):1397-1405

플라즈마 조사에 의한 전기분무합성 SiO₂ 코팅층의 물접촉각 변화

김재훈,이준성,김지영,김상섭,Kim, Jae-Hun,Lee, Junseong,Kim, Ji Yeong,Kim, Sang Sub 한국재료학회 2014 한국재료학회지 Vol.24 No.11

Hydrophilic $SiO_2$ layers were obtained by the atmospheric-pressure plasma treatment. Superhydrophobic $SiO_2$ layers were first deposited by the electrospray deposition method. The electrospunable solution that was prepared based on the solgel method was sprayed on Si (100) substrates. The surface of the electrosprayed $SiO_2$ layers consisted of the agglomeration of nano-sized grains, which led to a very high roughness and revealed a very high contact angle to water droplets over $162^{\circ}$. After having been exposed to the atmospheric $Ar/O_2$ plasma, the observed superhydrophobicity of the $SiO_2$ layers were greatly changed: a dramatic variation of the water contact angle from $162^{\circ}$ to $3^{\circ}$, namely realization of superhydrophillicity. Interestingly, the surface microstructure was almost preserved. According to the XPS analysis, it is more likely that thanks to the plasma exposure, the surface of $SiO_2$ layers will be cleaned in terms of organic species that are hydrophobic-inducing, consequently leading to the hydrophilic nature observed for the plasma-exposed $SiO_2$ layers.

경련만으로 발현된 중대뇌동맥 분지부의 미파열성 거대 동맥류 - 증례보고 -

김재훈,이형중,김광명,김재민,김영수,고용,오성훈,오석전,Kim, Jae Hoon,Yi, Hyeong Joong,Kim, Kwang Myung,Kim, Jae Min,Kim, Young Soo,Ko, Yong,Oh, Seong Hoon,Oh, Suck Jun 대한신경외과학회 2001 Journal of Korean neurosurgical society Vol.30 No.5

Intracranial giant aneurysms have been known to cause clinical signs and symptoms, either by rupture, compression of surrounding structures, repeated minor leakage, or cerebral ischemia due to thromboembolism. A giant aneurysm which manifests only a seizure disorder comprises relatively few contributions. The authors present a case of a giant, unruptured aneurysm solely presenting with generalized tonic-clonic type seizure in a 43-year-old man. Brain computed tomogram(CT) and 3-D CT angiogram demonstrated a huge calcified aneurysm at the bifurcation of right middle cerebral artery. Complete neck clipping and aneurysmectomy followed by uneventful neurologic recovery.

내경-후교통 동맥류 수술시 전 상상돌기 절제 유무에 대한 술전 혈관조영술의 의의

김재훈,김재민,이형중,백광흠,김충현,오석전,Kim, Jae Hoon,Kim, Jae Min,Yi, Hyeong Joong,Bak, Koang Hum,Kim, Choong Hyun,Oh, Suck Jun 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.9

Objective : Internal carotid-posterior communicating artery(IC-PC) aneurysms can be clipped easily without any special preparations. Occasionally, however, it is difficult to clip the low-lying IC-PC aneurysms without some kinds of additional procedures. Clinical Material and Methods : We experienced four cases of low-lying IC-PC aneurysms, which the intradural anterior clinoidectomy and/or anterior petroclinoid fold(APF) resection was essential to expose the proximal side of the aneurysmal neck and/or proximal control. One patient harbored two low-lying IC-PC aneurysms bilaterally. The patients were divided into two groups according to the necessity of anterior clinoidectomy : Group I(n=4) that needed an intradural clinoidectomy and/or APF resection and Group II(n=29) that had IC-PC aneurysms, easily clipped without any special preparation. Also, various radiometric parameters were measured through the preoperative angiograms. Results : The incidence of such aneurysms was 12% among a total of thirty-three surgically treated IC-PC aneurysms during lasr 3 years. Among four cases, three cases presented with subarachnoid hemorrhage and all aneurysmal sac projected to postero-inferior direction. In our study, We initially considered the necessity of intraoperative anterior clinoid process(ACP) removal and/or resection of APF in cases of shorter distance less than 5.6mm between the proximal aneurysmal sac and tip of the ACP(p<0.001), and the proximal portion of aneurysmal neck has located below the interclinoid line(p=0.001). Conclusion : Through a careful preoperative evaluation, some radiometric parameters can be used to determine whether the ACP should be removed in clipping of the low-lying IC-PC aneurysms. Unlike to total removal of the ACP, the intradural partial anterior clinolidectomy and/or APF resection, which are more familiar to surgeons, reduce the risks of the premature rupture, operative time, and also contribute a more precise clip placement with proximal control than the extradural clinoidectomy.

가단성 태스크들의 마감시간 스케줄링의 자원추가 분석

김재훈,Kim, Jae-Hoon 한국정보통신학회 2012 한국정보통신학회논문지 Vol.16 No.10

본 논문은 마감시간을 가지는 병렬 태스크들을 스케줄하는 문제를 다룬다. 특히, 가단성 태스크, 다시 말해서, 수행시간이 수행 머신들의 개수의 함수로 주어지는 태스크를 다룬다. 스케줄링 알고리즘의 목표는 마감시간 안에 수행을 끝마친 태스크들의 작업량의 합을 최대화하는 것이다. 이 문제는 NP-hard 문제로 알려져 있다. 따라서, 근사 알고리즘을 찾으려하고, 알고리즘의 성능은 최적 알고리즘 성능과의 비, 다시 말해서, 근사비를 구해서 분석한다. 특히, 본 논문에서는 알고리즘이 최적 알고리즘보다 많은 자원, 즉, 보다 많은 머신들을 가지는 경우에 근사비를 구할 것이다. 이것은 자원추가분석이라고 불린다. 본 논문은 최적 알고리즘보다 1.5배의 머신들을 사용해서 3.67의 근사비를 보장하는 스케줄링 알고리즘을 제안한다. In this paper, we deal with the problem of scheduling parallel tasks with deadlines. Parallel tasks can be simultaneously executed on various machines and specially, we consider the malleable tasks, that is, the tasks whose execution time is given by a function of the number of machines on which they are executed. The goal of the problem is to maximize the throughput of tasks completed within their deadlines. This problem is well-known as NP-hard problem. Thus we will find an approximation algorithm, and its performance is compared with that of the optimal algorithm and analyzed by finding the approximation ratio. In particular, the algorithm has more resources, that is, more machines, than the optimal algorithm. This is called the resource augmentation analysis. We propose an algorithm to guarantee the approximation ratio of 3.67 using 1.5 times machines.

한국어 기준명사 추출 및 그 응용

김재훈,Kim, Jae-Hoon 한국정보처리학회 2008 정보처리학회논문지B Vol.15 No.6

정보검색, 문서요약 등의 분야에서 명사추출은 매우 중요하다. 본 논문은 대량의 문서로부터 기준명사를 효과적으로 추출하기 위한 한국어 기준명사 추출 시스템을 제안하고 이를 문서요약 시스템에 적용한다. 기준명사는 명사들 중에서 기본이 되는 명사이며 복합명사는 포함되지 않는다. 본 논문에서는 두 가지 기술 즉 여과기법과 분리기법을 사용한다. 먼저 여과기법을 이용해서 명사를 포함하지 않은 어절을 미리 제거하고, 그리고 분리기법을 이용해서 명사가 포함된 어절에서 명사와 조사를 분리하고, 복합명사에 해당할 경우에는 각 명사를 분리하여 기준명사를 추출한다. ETRI 말뭉치를 대상으로 실험한 결과, 재현율과 정확률 모두 약 89% 정도의 성능을 보였으며, 제안된 시스템을 한국어 문서요약 시스템에 적용해 보았을 때, 좋은 결과를 얻을 수 있었다. Noun extraction plays an important part in the fields of information retrieval, text summarization, and so on. In this paper, we present a Korean base-noun extraction system and apply it to text summarization to deal with a huge amount of text effectively. The base-noun is an atomic noun but not a compound noun and we use tow techniques, filtering and segmenting. The filtering technique is used for removing non-nominal words from text before extracting base-nouns and the segmenting technique is employed for separating a particle from a nominal and for dividing a compound noun into base-nouns. We have shown that both of the recall and the precision of the proposed system are about 89% on the average under experimental conditions of ETRI corpus. The proposed system has applied to Korean text summarization system and is shown satisfactory results.

LNG 저장탱크용 9% Ni강 용접부의 저온피로균열진전 특성

김재훈,심규택,김영균,안병욱,Kim, Jae-Hoon,Shim, Kyue-Taek,Kim, Young-Kyun,Ahn, Byoung-Wook 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.5

The fatigue crack growth characteristics of base metal and weld joint of 9% Ni steel for LNG storage tank was carried out using CT specimen at room temperature and $-162^{\circ}C$. Fatigue crack growth rate of base and weld metals at RT and $-162^{\circ}C$ was coincided with a single line independent of the change of stress ratio and temperature. In the region of lower stress intensity factor range, fatigue crack growth rate at $-162^{\circ}C$ was slower than that at RT, and the slop of fatigue crack growth rate at $-162^{\circ}C$ increased sharply with propagating of fatigue crack, fatigue crack growth rate at RT and $-162^{\circ}C$ was intersected near the region of $2{\times}10-4\;mm$/cycle, and after the intersection region, fatigue crack growth rate at $-162^{\circ}C$ was faster than that at RT. The micro-fracture mechanism using SEM shows the ductile striation in the stable crack growth region. Also the defects of weld specimen after fatigue testing were detected using the A scan of ultrasonic apparatus.

환경정책, 재분배정책, 경제성장에 관한 정치경제학적 분석

김재훈,KIM, Jaehoon 한국개발연구원 2011 韓國 開發 硏究 Vol.33 No.2

본 논문은 경제적 불평등이 정치적 의사결정과정을 통하여 환경정책과 재분배 정책에 어떻게 영향을 미치는지를 분석하고 있다. 정치과정을 배제한 경제적 균형에서는 환경정책(배출세)의 도입이 미도입시와 비교하여 경제성장률의 상승을 가져올 수 있지만 그 효과에 불확실성이 존재함을 보이고 있다. 이와 달리 정치경제적 균형에서는 경제적 불평등도의 변화에 따라 환경정책과 재분배정책의 선택이 달라지는 것을 보이고, 그러한 정책 선택이 경제성장에 미치는 영향을 분석하고 있다. 보다 구체적으로 경제적 불평등도가 일정 수준으로 개선되어야 환경정책이 도입되고, 환경정책의 도입은 보다 강화된 재분배정책의 요구로 이어져 단기적으로 경제성장에 부정적인 영향을 줄 수 있음을 보이고 있다. 본 논문에서는 이러한 정치경제적 분석을 기초로 정책적 함의를 논의하고 있다. We analyse an overlapping generation model in which economic agents, especially their income distribution, influence environmental policy and redistributive policy through political decision making process. In an economic equilibrium which doesn't consider political process, the introduction of environmental policy is shown to increase economic growth rate. In contrast to an economic equilibrium, environmental policy can be adopted when economic inequality reduces to a certain threshold in a political economic equilibrium. The adoption of environmental policy, on the other hand, incurs the demand of strengthened redistributive policy, which in turn decreases economic growth in a short run. We discuss broad policy implications based on our political economic analyses.

지방분권제도에 대한 정치경제학적 분석: 재정자치 및 국회의원경선제도

김재훈,Kim, Jaehoon 한국개발연구원 2009 韓國 開發 硏究 Vol.31 No.1

본 연구는 지방교부세제도에서는 어떤 자치단체장이라도 지방교부금의 상한까지 사용하려 하고 재원이 다른 용도로 사용될 가능성이 상대적으로 높다는 측면에서 지방세를 통한 지방재원 조달의 경우보다 비효율적이라는 것을 이론적으로 보이고 있다. 특히, 지방교부세제도의 경우에는 지방정부의 재정한계를 감소시키더라도 이러한 재정낭비의 가능성은 감소하지 않는다는 문제가 있다. 보다 효율적인 지방자치를 위해서는 국세의 지방세로의 전환을 통하여 지방재원이 지역주민으로부터 나오는 지방세를 강화할 필요성이 있다. 더 나아가 현행 지방교부세제도와 지방세 및 국세 체계를 개편하여 지방에서 사용하는 재원은 기본적으로 지방이 부담한다는 원칙을 확립할 필요성이 있다. 다시 말하면, 자치단체의 권한과 책무를 엄격하게 규정하고 그에 대응하는 재정권한 또한 부여되었을 때에만 재정의 낭비적 요소를 막을 수 있을 것이다. 이와 함께 상향식 공천제도인 경선제도를 통하여 지역정치인으로서 능력이 검증된 인물들이 중앙정치로 나아갈 수 있는 경로를 열어주고, 이를 통하여 현직 지역구의원과의 경쟁을 통하여 현직 지역구의원들의 지역발전을 위한 더 많은 노력을 유도할 수 있다는 점에서 중앙정치의 발전뿐만 아니라 지역발전에 보다 효율적인 제도라는 것을 보이고 있다. 다른 한편, 이러한 경선제도는 중앙정치로의 유인제공을 통하여 지방정치인의 지대추구행위를 감소시키는 효과도 있다. 더욱이 경선제도는 중앙정치에 참여하고자 하는 많은 능력 있는 인물들을 지방정치로 유도함으로써 지방발전을 도모할 수 있는 부수적인 효과도 얻을 수 있다. 이러한 중앙정치와 지방정치의 선순환적인 구조를 통하여 중앙정치와 지방분권 및 지역발전을 도모할 수 있다는 측면에서 경선제도의 도입이 긴요하다고 판단된다. This paper studies the logic of fiscal constraints and fiscal autonomy in a political agency model with both moral hazard and adverse selection. The electoral process not only disciplines incumbents who may act against the public interest but also opts in politicians who are most likely to act along voters' interests. We characterize perfect Bayesian equilibria under shared tax system and fiscal autonomy with fiscal constraints for local public good provision. It is shown that the local voters' expected welfare under fiscal autonomy is higher than under shared tax system if the same fiscal constraints are applied. In order to examine the effects of party's candidate selection processes on the behavior of local politician and national politician, we extend the model to an environment where local politician can compete for the candidacy of national assembly with incumbent national politician. If local politician wins majority of votes against incumbent national politician, then he can move on to serve as a national politician. Otherwise, his political career will end as a local politician. It is the gist of this primary system portrayed by this setup that local politician and national politician compete to garner more votes. Therefore, primary system as a candidate selection mechanism enhances local residents' welfare compared to top-down candidate selection processes.