X-ray Irradiation Induced Reversible Resistance Change in Pt/TiO₂/Pt Cells

Chang, Seo Hyoung,Kim, Jungho,Phatak, Charudatta,D’Aquila, Kenneth,Kim, Seong Keun,Kim, Jiyoon,Song, Seul Ji,Hwang, Cheol Seong,Eastman, Jeffrey A.,Freeland, John W.,Hong, Seungbum American Chemical Society 2014 ACS NANO Vol.8 No.2

<P>The interaction between X-rays and matter is an intriguing topic for both fundamental science and possible applications. In particular, synchrotron-based brilliant X-ray beams have been used as a powerful diagnostic tool to unveil nanoscale phenomena in functional materials. However, it has not been widely investigated how functional materials respond to the brilliant X-rays. Here, we report the X-ray-induced reversible resistance change in 40-nm-thick TiO<SUB>2</SUB> films sandwiched by Pt top and bottom electrodes, and propose the physical mechanism behind the emergent phenomenon. Our findings indicate that there exists a photovoltaic-like effect, which modulates the resistance reversibly by a few orders of magnitude, depending on the intensity of impinging X-rays. We found that this effect, combined with the X-ray irradiation induced phase transition confirmed by transmission electron microscopy, triggers a nonvolatile reversible resistance change. Understanding X-ray-controlled reversible resistance changes can provide possibilities to control initial resistance states of functional materials, which could be useful for future information and energy storage devices.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2014/ancac3.2014.8.issue-2/nn405867p/production/images/medium/nn-2013-05867p_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn405867p'>ACS Electronic Supporting Info</A></P>

콤바인 HST 전자제어시스템 개발

서신원(Sin-Won Seo),허윤근(Yun-Kun Huh),이제용(Je-Yong Lee),이창규(Chang-Kyu Lee),배근수(Keun-Soo Bae) 충남대학교 농업과학연구소 2011 농업과학연구 Vol.38 No.1

I/An electro-hydraulic transmission having advantages of convenience, safety, simple linking and high power, and an electronic control system were designed and fabricated. In this study, characteristics of the control system were investigated through outdoor tests for evaluation of installation of the system on a combine. Major findings were as followings. 1. Experiment for performance evaluation of the control system was conducted on concrete road. With steering lever in neutral position, driving HST swash plate and left/right wheel speed increased in proportion to driving lever angle. In case of steering control, steering swash plate angle changed in proportion to steering lever angle. This should cause increase in outer wheel speed, but it was observed that HST swash plate was controlled toward neutral to maintain the speed before steering. As a result, speed before steering was maintained despite the change in outer wheel speed by steering HST swash plate angle change. 2. It was observed that the HST system enabled steering with outer wheel maintained at constant speeds while inner wheel speed decreased, which was more stable than conventional mechanical links. In addition, for the selected 5 criteria, experiment showed satisfactory results and it was judged that installation on real vehicle would be feasible. 3. The control system showed response property of appropriate forward/reverse movement and lift/right steering, without causing any problems during experiment on concrete. Result of response property experiment on field operation also showed appropriate control over forward/reverse movement and left/right steering

Finding key vulnerable areas by a climate change vulnerability assessment

Kim, Ho Gul,Lee, Dong Kun,Jung, Huicheul,Kil, Sung-Ho,Park, Jin Han,Park, Chan,Tanaka, Riwako,Seo, Changwan,Kim, Ho,Kong, Wooseok,Oh, Kyusik,Choi, Jinyong,Oh, Young-Ju,Hwang, Gangseok,Song, Chang-Keun Springer Netherlands 2016 Natural hazards Vol.81 No.3

<P>Extreme climate events such as typhoons, heat waves, and floods have increased in frequency with climate change. Many municipalities within the Republic of Korea (ROK) have experienced damage from these events, necessitating countermeasures. Vulnerability assessment has been suggested in the implementation of a national plan for reducing damage resulting from climate change. Thus, in this study, we assess the vulnerability of the ROK and identify key vulnerable municipalities in support of the national adaptation plan. We create a framework for assessing the vulnerability of all 232 municipalities of the ROK with respect to 32 items in 7 fields. The framework regards decision makers' comprehension and availability of data as important factors. We assess the vulnerability index of each municipality by using variables of climate exposure, sensitivity, and adaptation capacity. The weights of variables are determined by the Delphi method. We used the representative concentration pathways 8.5 climate scenario to reflect future climate exposure for the vulnerability assessment. From the analysis, vulnerability maps are prepared for the 32 items of 7 fields, and key vulnerable municipalities are identified by aggregating the maps. The distribution of vulnerable municipalities changes with the future climate conditions. These maps provide a scientific and objective basis for the ROK government to establish adaptation plans and allocate resources. The ROK government can utilize the results to identify the characteristics of highly vulnerable areas, and municipalities can use the results as a basis for requesting support from the national government.</P>

'82學年度 新入生實態調査 結果分析

張忠根,片瑞英,尹禮鉉 충남대학교 1982 學生生活硏究 Vol.10 No.1

전신성 홍반성 루푸스에서 F-18 FDG PET상 기저핵 포도당대사 증가 소견을 보이는 무도병 1예 : Evidence for Bilateral Putaminal Hypermetabolism on F-18 FDG PET

서욱장,정선미,고수진,이창근,김재승,임주혁,유빈,문희범 대한핵의학회 2003 핵의학 분자영상 Vol.37 No.5

Purpose: We describe a 54-year-old woman with systemic lupus erythematosus (SLE) who suddenly presented with chorea and had positive antiphospholipid antibodies. F-18 FDG PET showed abnormally increased glucose metabolism in bilateral putamen and primary motor cotex. Tc-99m ECD SPECt also showed abnormally increased regional cerebral blood flow in bilateral putamen. She was treated with corticosteroid and aspirin after which the symptoms improved. Four months later, follow up F-18 FDG PET showed improvement with resolution of hypermetabolism in bilateral putamen. This case suggests that striatal hypermetabolism is associated with chorea in SLE.

전경대원에서 발생한 결핵의 임상 양상

문창기,박상준,조민구,김영중,김소연,김윤권,정준오,안석진,김은실,서승오,김지훈,최원제,이윤영,박형기,최규영,김현근 대한감염학회 2006 감염과 화학요법 Vol.38 No.6

Background: The purpose of this study was to document the incidence and clinical characteristics of patients with tuberculosis (TB) in combat and auxiliary police, living in a group, in Korea where the incidence rate of active TB in a general population is higher than in Western countries. Materials and Methods:We retrospectively reviewed the medical records of all tuberculosis patients diagnosed at National Police Hospital from January 2002 through December 2004. Results:In 2002-2004, a total of 156 cases of tuberculosis were identified with the mean (Standard deviation) age of 20.6 (±1.0) years. Of these, 134 (85.9%) patients were registered as new cases, 11 (7.1%) as relapse, 2 (1.3%) as failure, 5 (3.1%) as treatment-after-default cases whereas 4 (2.6 %) patients were not included in any categories. Average annual new TB rate and smear-positive TB rate were 86.5/10^(5) and 17.4/10^(5) person-years, respectively. In 12 of 31 smear-positive cases, time from onset of symptoms to diagnosis was more than 30 days. Two multidrug-resistance TB cases were identified and two suspected outbreak episodes of TB had occurred during 3 years. Conclusion:There was no statistically significant difference in the incidence rate of new cases of TB between the general population aged 20 to 29 years and combat and auxiliary police in Korea. 배경 : 국내 결핵의 발생은 감소 추세에 있으나 여전히 후진국형 발생양상을 보이고 있다. 특히 집단생활을 하는 젊은이들에서 발생하는 결핵의 유행이 간헐적으로 알려지고 있어 우려를 낳고 있다. 이에 저자들은 최근 전경대원의 결핵 발병 양상에 대해 알아보고자 본 연구를 시행하였다. 재료 및 방법 : 2002년 1월부터 2004년 12월까지 3년간 경찰병원에서 결핵 진료를 받은 전경대원의 의무기록을 후향적으로 분석하여 연도별 결핵 신환발생률, 도말양성결핵 신환율, 진단 지연, 집단발병, 다제내성결핵을 조사하였다. 결과 : 연도별 결핵 신환자 수(10만명당 발생추정치)는 2002년 50명(83.6명), 2003년 42명(83.7명), 2004년 42명(93.5명)이었고 도말양성 폐결핵 신환자 수는 2002년 10명(16.7명), 2003년 11명(21.9명), 2004년 6명(13.4명)이었다. 3년간 도말양성 폐결핵 환자는 31명이 있었고 그 중 12명은 호흡기 증상 발생 30일이 지나서 진단을 받았다. 다제내성 결핵은 2명이 있었으며 결핵의 집단발병이 의심되는 사례는 2차례 있었다. 결론 : 전경대원과 20-29세 연령군 일반인의 결핵 신환발생률, 도말양성 폐결핵 발생률의 통계적으로 유의한 차이는 없었다.

치과용 도재분말의 제조 및 물리적 성질

염근창,고대진,장감용,이서영,김경남 大韓齒科器材學會 1994 대한치과재료학회지 Vol.21 No.1

In this study, the prepared glasses were heat-treated to precipitate the leucite crystal in order to control the thermal expansion coefficient which is an important property of dental porcelain powder. The effect of addition of Li₂O and Na₂O on the amount of the precipitated leucite crystal were also examined. The mixing ratio of the leucite-containing glass must be controlled to match the thermal expansion coefficient of dental porcelain to that of metal. The physical properties of the dental porcelain powder prepared in this study were characterized. The results of this study were obtained as follows : 1. Conditions for the preparation of the maximum amount of leuctie crystal were compostion L-2(2.0 wt% Li₂O added) heat-treated at 950℃. 2. The phase of the precipitated crystals was turned out to be the tetragonal leucite crystal. 3. Maximum relative crystallinity was 64.2% for composition L-2, heat-treated at 950℃. Its linear thermal expansion coefficient was 16.1×10-6/℃ in the range of room temperature to 500℃. 4. The optimum mixing ratio of the leucite-containing glass was 45% in order to match the thermal expansion coefficient of dental porcelain to that of metal. In this case, the thermal expansion coefficient of the prepared dental porcelain was 10.6×10-6/℃ (∼500℃). 5. The physical and chemical properties of the prepared dental porcelain were suitable for the requirements of ISO 6872 and 9693.

多品種에 관한 確率的 原價-操業度-利益 分析에 관한 硏究

李相道,徐洵根,李昌燮 동아대학교 공과대학 부설 한국자원개발연구소 1986 硏究報告 Vol.10 No.2

Previous stochastic cost-volume-profit(CVP) models have assumed that price and costs were known with certainty. Subsequently this assumption was relaxed, and CVP models were extended to incorporate uncertainty in price and costs. This paper expands on prior discussions of the mean, the variamce and the contribution margin per unit of each product. As the result of using Beta distribution to estimate of random variable's variance, it is proved to have generalization than traditional method when the variance has large value.

組立工程의 確率的 라인 균형화에 관한 硏究

李相道,徐洵根,李昌燮 동아대학교 공과대학 부설 한국자원개발연구소 1987 硏究報告 Vol.11 No.2

This paper presents a heuristic procedure for the design of assembly lines with variable task times. An efficient balancing algorithm, which is integrated comprehensively an appropriate remedial action depended on the characteristics of process and product when the cycle time is exceeded, is proposed. And, computer aided solution procedure is programmed for the proposed method including evaluation creteria and biased sampling. An illustration of numerical example and experimentation by microcomputer is conducted.

BIM 도입 후 설계사무소 실무자들의 직무스트레스 분석

서희창,오중근,김재준,Seo, Hee-Chang,Oh, Jung-Keun,Kim, Jea-Jun 한국건설관리학회 2012 한국건설관리학회 논문집 Vol.13 No.4

오늘날의 기업들은 무한 경쟁과 불확실한 경영환경 속에 있으며, 이로 인해 실무자들은 다양한 직무요구들과 스트레스에 노출되어 있다. 특히 설계사무소 직원들은 타 산업현장과 달리 작업에 대한 강도가 커서 육체적으로 힘들고, 타 산업의 주 5일제 근무와 달리 공정이 상호 관련되어 있기 때문에 정기적인 공휴일과 휴가가 보장되기 어렵다. 또한 최근 건설 산업에서는 BIM이 도입되면서 업무환경 및 범위 그리고 역할 등과 같은 개인적 역할뿐만 아니라 조직차원에서의 다양한 변화가 요구되기 때문에 이로 인한 직무스트레스의 범주 및 요인 또한 변하고 있는 상황이다. 이에 본 연구에서는 BIM을 도입 한 이후 설계사무소 실무자들의 직무스트레스 수준 및 유발요인을 확인하여 경력, 직급, 성별, BIM 교육 및 BIM 템플릿 유/무 등과 같은 특성에 따른 직무스트레스를 파악하였다. 이는 추후 활용도가 높을 것으로 예상되는 BIM기반 프로젝트의 주 참여자인 설계사무소의 업무환경을 구축하는데 의의가 있다. Today, companies exist amid unlimited competition and uncertain adminstration environment, so hands-on workers are being exposed to various job requirements and stress due to this. Especially, employees in the design firm are physically difficult because of heavy working intensity unlike other industrial field, and because the process is interrelated unlike working of a five-day workday of the other industry, it is difficult to guarantee periodic holidays and vacation. In addition, recently, while BIM is introduced in the construction industry, various changes in the individual role as well as organizational dimension such as business environment and scope & role, etc. are required, so it is the actual situation that the category and factors of job stress due to this are being also changed. Accordingly, this research has grasped important and weak sectors according to characteristics such as career, position, gender, education and existence/nonexistence of BIM template, etc. by confirming a job stress level and inducing factors of hands-on workers at the design firm. This research has a meaning in constructing a business environment of a design firm that is a main participant of BIM-based projects that are expected to have high utilization in the future.