• 제목/요약/키워드: Center Prior

검색결과 1,358건 처리시간 0.029초

Improvement of Switching Speed of a 600-V Nonpunch-Through Insulated Gate Bipolar Transistor Using Fast Neutron Irradiation

  • Baek, Ha Ni;Sun, Gwang Min;Kim, Ji suck;Hoang, Sy Minh Tuan;Jin, Mi Eun;Ahn, Sung Ho
    • Nuclear Engineering and Technology
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    • 제49권1호
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    • pp.209-215
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    • 2017
  • Fast neutron irradiation was used to improve the switching speed of a 600-V nonpunch-through insulated gate bipolar transistor. Fast neutron irradiation was carried out at 30-MeV energy in doses of $1{\times}10^8n/cm^2$, $1{\times}10^9n/cm^2$, $1{\times}10^{10}n/cm^2$, and $1{\times}10^{11}n/cm^2$. Electrical characteristics such as current-voltage, forward on-state voltage drop, and switching speed of the device were analyzed and compared with those prior to irradiation. The on-state voltage drop of the initial devices prior to irradiation was 2.08 V, which increased to 2.10 V, 2.20 V, 2.3 V, and 2.4 V, respectively, depending on the irradiation dose. This effect arises because of the lattice defects generated by the fast neutrons. In particular, the turnoff delay time was reduced to 92 nanoseconds, 45% of that prior to irradiation, which means there is a substantial improvement in the switching speed of the device.

A Study on the Interaction between Corporate Reputation and Negativity Framing on Consumer Evaluation of Corporate Social Responsibility

  • Lee, Chungyeol;Chang, Dae Ryun;Kim, Nayeon;Lee, Hosun
    • Asia Marketing Journal
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    • 제17권4호
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    • pp.105-123
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    • 2016
  • Do corporate social responsibility (CSR) initiatives lead to positive outcomes for companies? Although it is commonly accepted that CSR is a necessary component of modern marketing communication, the empirical evidence shows that that is not always the case. If CSR is sometimes not conducive to better marketing, it behooves firms to determine the right conditions that foster more effective CSR. It is in that vein that this study aims to add to the growing body of marketing and CSR literature through a series of experiments that examines the dynamics between prior attitude toward the company, the fit between the company and the CSR cause, and consumers' accessible thoughts. This study finds that the prior corporate reputation has an impact on how consumers evaluate the CSR activities of companies. Moreover, we show that the degree of accessible thoughts and their valence can change the moderating effect of the fit between the company and the CSR cause. This is because negative information is perceived as being more diagnostic than positive information in an evaluation situation. We demonstrate that companies that have lower prior public reputations can improve the evaluation of their CSR activities in two major ways: (1) by finding CSR causes that have a lower fit with their business, or (2) by providing information that allow consumers to access more positive thoughts about the CSR activity.

Application of Percentile Rainfall Event for Analysis of Infiltration Facilities used by Prior Consultation for LID (Low Impact Development)

  • Kwon, Kyung-Ho;Song, Hye-Jin
    • KIEAE Journal
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    • 제15권5호
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    • pp.5-12
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    • 2015
  • Purpose: Retention and infiltration of small and frequently-occurring rainfall by LID facilities account for a large proportion of the annual precipitation volume. Based on 4 standard facilities such as Porous Pavement, Infiltration Trench, Cylindrical Infiltration Well, Rectangular Infiltration Well by Seoul Metropolitan Handbook of the Prior Consultation for LID. The total retention volume of each facility was calculated according to the type and size. The Purpose of this study is to find out the quantitative relationship between Percentile Rainfall Event and Design Volume of Infiltration Facilities. Methode: For the estimation of Percentile Rainfall Event, Daily Precipitation of Seoul from 2005 to 2014 was sorted ascending and the distribution of percentile was estimated by PERCENTILE spreadsheet function. The managed Rainfall Depth and Percentile of each facility was calculated at the several sizes. In response to the rainwater charge volume of 5.5mm/hr by the Category "Private large site", the 3 types of facilities were planned for example. The calculated Rainfall Depth and Percentile were 54.4mm and 90% by the use of developed Calculation-Module based on the Spreadsheet program. Result: With this Module the existing Designed Infiltration volume which was introduced from Japan was simply converted to the Percentile-Rainfall-Event used in USA.

B737NG 항공기 이륙 중 미부지면접촉에 관한 연구 (A Study on B737NG Aircraft Tail Strike during Takeoff)

  • 노건수
    • 한국항공운항학회지
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    • 제17권4호
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    • pp.70-75
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    • 2009
  • According to the aviation statistics, tail strike incidents and accidents are cyclic. Although many tail strikes occurred during takeoff, these are less than during landing cases. Many cases are related on human factors. In my opinion it is possible to analyze the causes of takeoff tail strikes to some extent. There are major casual factors of tail strike during takeoff such as; (1) Mis-trimmed horizontal stabilizer (2) premature rotation prior to $V_R$ (3) Excessive pitch up rate during rotation (4) Improper use of the flight director. Among these causes improper use of flight director is excluded in this paper because it is recommended that pilot should use flight director after airborne. So I analyzed the other three causes as following. Firstly, because mis-trimmed stabilizer is related to center of gravity(CG), the relationship between stabilizer and CG is reviewed. Secondly, concerned premature rotation prior to $V_R$ I reviewed the background of rotation speed($V_R$) establishment and analyzed theoretically what speed leads to tail strikes. Thirdly, concerning excessive pitch up rate during rotation I analyzed what excessive pitch up rate can decrease ground clearance while using FDR data.

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Korean red ginseng prevents ethanol-induced hepatotoxicity in isolated perfused rat liver

  • Park, Hye-Min;Kim, Shang-Jin;Go, Hyeon-Kyu;Kim, Gi-Beum;Kim, Sung-Zoo;Kim, Jin-Shang;Kang, Hyung-Sub
    • 대한수의학회지
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    • 제51권2호
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    • pp.159-164
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    • 2011
  • Alcohol abuse and its medical and social consequences are a major health problem in many areas of the world. Korean red ginseng (KRG) has been traditionally used for the treatment of liver disease. This study was conducted to evaluate the hepatoprotective effects of KRG against hepatotoxicity in Sprague- Dawley rats treated with ethanol (EtOH). Administration of EtOH for 20 days induced significant changes in serum biochemical parameters (aspartate aminotransferase, alanine transaminase, and glucose) accompanied by histological changes in the liver tissue. Treatment with KRG prior to administration of EtOH inhibited the EtOH-induced biochemical and histological changes of the liver. In perfused rat livers, administration of EtOH caused an increase in lactate dehydrogenase (LDH) release into the perfusate and activated the pro-apoptotic Bax protein but inhibited the anti-apoptotic Bcl-2 protein. Pretreatment with KRG prior to administration of EtOH decreased the EtOH-induced LDH release and inhibition of Bcl-2 protein. These results suggest that KRG exerts anti-apoptotic effects and alleviated EtOH-induced liver injury in rats.

A long-term tunnel settlement prediction model based on BO-GPBE with SHM data

  • Yang Ding;Yu-Jun Wei;Pei-Sen Xi;Peng-Peng Ang;Zhen Han
    • Smart Structures and Systems
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    • 제33권1호
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    • pp.17-26
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    • 2024
  • The new metro crossing the existing metro will cause the settlement or floating of the existing structures, which will have safety problems for the operation of the existing metro and the construction of the new metro. Therefore, it is necessary to monitor and predict the settlement of the existing metro caused by the construction of the new metro in real time. Considering the complexity and uncertainty of metro settlement, a Gaussian Prior Bayesian Emulator (GPBE) probability prediction model based on Bayesian optimization (BO) is proposed, that is, BO-GPBE. Firstly, the settlement monitoring data are analyzed to get the influence of the new metro on the settlement of the existing metro. Then, five different acquisition functions, that is, expected improvement (EI), expected improvement per second (EIPS), expected improvement per second plus (EIPSP), lower confidence bound (LCB), probability of improvement (PI) are selected to construct BO model, and then BO-GPBE model is established. Finally, three years settlement monitoring data were collected by structural health monitoring (SHM) system installed on Nanjing Metro Line 10 are employed to demonstrate the effectiveness of BO-GPBE for forecasting the settlement.

Thirty-Three Years Old Modified Senning Operation

  • Michalis, Alkiviadis;Kanakis, Meletios A.;Thanopoulos, Vassilios;Laskari, Cleo;Mitropoulos, Fotios A.
    • Journal of Chest Surgery
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    • 제47권4호
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    • pp.394-397
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    • 2014
  • Numerous technical modifications and various complications of the Senning procedure have been described in the literature. We describe the excellent clinical status and anatomic result of a 33-year-old patient who underwent a modified Senning operation using the left atrial appendage for reconstruction more than 30 years prior to presentation.

대장암에서 장세척물의 세포학적 소견 (Cytologic Findings of Colon Lavage Fluid in Colon Cancer)

  • 이혜경;주명진;이광민;정동규;최용우
    • 대한세포병리학회지
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    • 제7권1호
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    • pp.103-106
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    • 1996
  • Although exfoliative colonic cytology for the diagnosis of colorectal cancer has been largely abandoned due to the widespread use of colonoscopy, some authors still insiston the usefulness of colon lavage fluid. We tried evaluating the diagnostic feasibility of colon lavage fluid cytology using an orally administered balanced electrolyte solution. We collected colon lavage fluids in 106 patients prior to colonoscopy and reviewed the slides. Cytologic examination revealed neoplastic cells in 7 of 16(44%) cases of endoscopically proven adenocarcinoma patients. Therefore, we thin cytologic study of colon lavage fluid may be considered as one of the noninvasive diagnostic tools in colorectal cancer.

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Amorphous Silicon Gate Driver with High Stability

  • Koo, Ja-Hun;Choi, Jae-Won;Kim, Young-Seoung;Kang, Moon-Hyo;Jang, Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1271-1274
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    • 2006
  • Integrated a-Si:H gate driver with high reliability has been designed and simulated. The proposed a-S:H gate driver has only one reset transistor under AC driving for P and output node. These reset transistors show much less degradation than those under DC driving. The simulation results show that the lifetime and response time are improved significantly compared with those of the prior circuit.

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1kW급 가정용 연료전지 시스템 실증 연구 (Development of 1kW Class PEFC System for Residential Applications)

  • 최동민;신범수;박연구;함미숙;심재휘
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.174-176
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    • 2008
  • HYOSUNG manufactured and tested 1kw class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed Power conditioning system that performs about 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sureces by testing the characteristics of systems and performances of main component.

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