• 제목/요약/키워드: Roll Stress

검색결과 149건 처리시간 0.03초

Tri-Gate MOSFET에 SPACER가 단채널 및 열화특성에 미치는 영향 (The impact of Spacer on Short Channel Effect and device degradation in Tri-Gate MOSFET)

  • 백근우;정성인;김기연;이재훈;박종태
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2014년도 추계학술대회
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    • pp.749-752
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    • 2014
  • Spacer 유무와 핀 폭, 채널길이에 따른 n채널 MuGFET의 단채널 및 열화 특성을 비교 분석 하였다. 사용된 소자는 핀 수가 10인 Tri-Gate이며 Spacer 유무에 따른 핀 폭이 55nm, 70nm인 4종류이다. 측정한 소자 특성은 DIBL, subthreshold swing, 문턱전압 변화 (이하 단채널 현상)과 소자열화이다. 측정 결과, 단채널 현상은 spacer가 있는 것이 감소하였고, hot carrier degradation은 spacer가 있고 핀 폭이 작은 것이 소자열화가 적었다. 따라서, spacer가 있는 LDD(Lightly Doped Drain) 구조이며 핀 폭이 작은 설계방식이 단채널 현상 및 열화특성에 더욱 바람직하다.

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복합조직강의 고속인장 결과를 이용한 컴퓨터 전산모사와 실제 충돌시험 결과와의 비교 연구 (A Comparative Study of Computer Simulation using High-Speed Tensile Test Results with Actual Crash Test Results of DP Steels)

  • 방형진;최일동;강성규;문만빈
    • 대한금속재료학회지
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    • 제50권12호
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    • pp.873-882
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    • 2012
  • Dual Phase (DP) steel which has a soft ferrite phase and a hard martensite phase reveals both high strength and high ductility and has received increased attention for use in automotive applications. To conduct structural analysis to verify vehicle safety, highly credible experimental results are required. In this study, tensile tests were performed in a strain rate range from $10^{-4}/s$ to 300/s for Sink Roll-Less (SRL) hot-dip metal coated sheets. Collision properties were estimated through simulation by LS-DYNA using the stress-strain curve obtained from the tensile test. The simulation results were compared with the actual crash test results to confirm the credibility of the simulation. In addition, a tensile test and a crash test with 2% prestrain and a baking (PB) specimen were evaluated identically because automotive steel is used after forming and painting. The mechanical behaviors were improved with an increasing strain rate regardless of the PB treatment. Thus, plastic deformation with an appropriate strain rate is expected to result in better formability and crash characteristics than plastic deformation with a static strain rate. The ultimate tensile strength (UTS) and absorbed energy up to 10% strain were improved even though the total elongation decreased after PB treatment, The results of the experimental crash test and computer simulation were slightly different but generally, a similar propensity was seen.

신생아집중간호단위 환경과 저체중출생아의 반응에 대한 연구 (A Study on the Environment for Lowbirth Weight Infants in Neonatal Intensive Care Unit in the United States)

  • 한경자
    • Child Health Nursing Research
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    • 제4권2호
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    • pp.159-176
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    • 1998
  • In effort to conduct comparative study on the caregiving environment of Neonatal Intensive Care Unit(NICU) in both U. S and Korea, this study was been conducted first in the U.S. Purpose : The purpose of this study is to identify the physical environment and direct caregiving practices to lowbirth weight infants in NICU in the US. It also aims to examine the NICU outcome status and behavioral reponses of lowbirth weight infants. Methods : A study design using descriptive and inferential statistics was been conducted through an observational, field method. A sample of 15 preform infants admitted to NICU were recruited for the study. The subjects were those with birth weight between 1,000 gm to 1,500 gm, born at the gestation period of 27 to 33 weeks, and without any chromosomal or other genetic anomalies, major congenital infections, or maternal illness. Thirty minutes observation(three times of ten minutes of continuous observation)of the infant's behavior and physiological status, and an four-hour observation of the physical environment and direct care giving procedures were been conducted on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. The data to be collected were in four areas : the demograghic characteristics of the infants, the physical environment and care giving procedures, the frequency of the infant's designated behavior and physiological response, and NICU outcome variables. A descriptive analysis and Kruskal-Wallis, Pearson r were been applied according to variable characteristics. Results : 1. Mother's mean age was 29.47. The sample consisted of 6 males and 9 females. Mean gestational ages were 29.17 weeks. Mean birth weight was 1236.33g. Mean Apgar scores at one minute were 6.6, and 7.8 at five minutes. 2. The location for the incubator was in the distance from the light, X-ray screens and nursing station, in proximity to side-lamp, telephone and faucet on the third day after birth. The location for the incubator was in the distance from the light and radio on the tenth day and in proximity to nursing station on the day of dischage from the NICU or at 34weeks postconception. 3. Nesting was the most applying aids to the infants. And foot roll, shielding and plastic frame were frequently using by nurses for facilitating well modulated restful posture. 4. There were statistically significant changes in the patterns of physical environment included locating the infant's incubator and bedding, specific aids to self regulation on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. 5. Statistically significant changes were not appeared in the patterns of direct caregiving procedure to the infants included stress inducing or reducing manipulations on the 3rd and 10th day after birth, and on the day of discharge from the NICU or at 34weeks postconception. 6. The stress response of the infants in NICU were significantly reduced as the infants grow older. 7. There were not statistically significant correlation between the physical envronment and the stress responses of the infants in NICU. 8. There were statistically significant correlation between the direct caregiving procedure to the infants and the stress response of the infants in NICU in the second and third observation on the day three. 9. Average weight gain per day from birth to discharge was 38.73g, number of days in the hospital was 42.60, number of days before bottle feeding was 3.6. Postconception age starting bottle feed ing was 31/sup +5/ weeks. Number of days on mechanical ventilator was average 7.64, 11.42 was an average number of days of oxygen need. Conclusion : It, thus, appears that to minimize the sensorymotor stimulation for the low birthweight preterm infant in NICU, manipulation of care giving practices to the babies whatever the stress inducing or reducing procedures, have to be limited in the immediate early stage after birth. And it needed to be reexamine to identify the appropriate and specific physical environment and the patterns of direct caregiving to the low birthweight preform infant as the infants grow older in NICU.

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IPA를 활용한 웰빙 퓨전 메뉴의 중요도-성취도 연구 (A Study on Importance-Performance of Wellbeing Fusion Menu using IPA)

  • 강혜정;이연정
    • 한국조리학회지
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    • 제16권2호
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    • pp.77-95
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    • 2010
  • 본 연구는 퓨전 레스토랑 이용 고객의 웰빙 퓨전 메뉴에 대한 중요도, 성취도(만족도) 품질 속성을 분석하여 세분화된 마케팅 방향을 설정하는데 유용한 정보를 제공하며, 향후 퓨전 레스토랑의 메뉴 개선 방안 모색과 동시에 효과적인 발전 방안을 제시하고자 한다. 퓨전 레스토랑의 웰빙 퓨전 메뉴 속성별 중요도, 성취도(만족도) 평가에 있어서 중요도가 성취도(만족도)보다 높은 것으로 나타났다. 고객은 음식의 맛, 식재료의 청결성, 기물의 청결성, 메뉴의 질, 음식의 신선도 등은 높게 평가한 것으로 나타났다. 퓨전 레스토랑에서 다소 많이 판매되는 웰빙 퓨전 메뉴에 대한 조사 대상자들의 섭취 경험을 조사한 결과, 가장 많은 섭취 경험을 가지고 있는 웰빙 퓨전 메뉴는 자장면(푸른면)으로 나타났고, 그다음은 단 호박 샐러드, 연어 샐러드, 새우 야채 그라탕 등으로 나타났다. 반면에 오븐 들깨 그라탕, 석류 드레싱 두부, 찹쌀가루 베이컨 롤, 석류 드레이싱 베이컨 등에 대해서 상대적으로 낮은 섭취 경험을 가지고 있는 것으로 나타났다. 퓨전 레스토랑의 웰빙퓨전 메뉴 속성별 IPA 분석 결과, 기존의 좋은 품질을 계속 유지하는 것이 바람직한 종요도와 성취도(만족도) 모두 높은 1사분면에는 음식의 맛, 식재료의 청결성, 기물의 청결성, 음식의 신선도, 메뉴의 질, 다이어트 메뉴(저지방, 저칼로리), 채식 메뉴, 음식의 영양, 메뉴의 다양성 등이 포함되었고, 중요도는 높은 반면에 이 평가 속성에 대한 성취도(만족도)는 낮게 평가되어 여기에 집중하여 우선적으로 시급히 개선해야 할 2사분면에는 가격, 기존 음식과의 차별성, 친환경 유기농 식재료로 나타났다.

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Fe-X%Mn-5Cr-5Co-4Si 합금 리본의 변태특성 및 형상기억능에 미치는 열처리 영향 (Influence of Heat Treatment on Transformation Characteristics and Shape Recovery in Fe-X%/Mn-5Cr-5Co-4Si Alloy Ribbons)

  • 강후원;지광구;장우양;강조원
    • 열처리공학회지
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    • 제14권3호
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    • pp.160-166
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    • 2001
  • The change of ribbon geometry, microstructure and shape recovery with Mn contents, wheel speed and various annealing temperature have been studied in Fe-X%Mn-5Cr-5Co-4Si (X%=15, 20, 24) shape memory alloy (SMA) ribbons rapidly solidfied by single roll chill-block melt-spinning process. The thickness and width of melt-spun ribbons are reduced, results in refining and uniformalizing grains with increasing wheel speed. In the ribbons melt-spun at a wheel speed of 15m/sec, both ${\varepsilon}$ and ${\alpha}^{\prime}$martensites are formed in ribbon 1 (15.5wt%Mn), while only ${\varepsilon}$ martensite is revealed in ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn). The volume fraction of ${\varepsilon}$ martensite is decreased with increasing Mn contents, and those of ${\varepsilon}$ as well ${\alpha}^{\prime}$martensites are increased due to thermal stress relief and grain growth with increasing annealing temperature. Ms temperatures of the ribbons 1, 2 and 3 are fallen with increasing Mn contents. $M_s$ temperatures of the ribbons 1, 2 and 3 annealed at $300^{\circ}C$ for 3 min are risen abruptly, but are nearly constant even at higher annealing temperature, i.e., 400, 500 and $600^{\circ}C$ for 3 min. Shape recovery of the ribbons 1, 2 and 3 increased 30%, 52% and 69% with Mn contents, respectively. Shape recovery of ribbon 1 (15.5wt%Mn) formed ${\varepsilon}$ and ${\alpha}^{\prime}$martensites decreased because of the presence of ${\alpha}^{\prime}$martensite but those of ribbon 2 (20.2wt%Mn) and ribbon 3 (23.5wt%Mn) formed ${\varepsilon}$ martensite increased with increasing annealing temperature.

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국내·외 GM식물의 개발 및 산업화 현황 (Current status on the development and commercialization of GM plants)

  • 이신우
    • Journal of Plant Biotechnology
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    • 제37권3호
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    • pp.305-312
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    • 2010
  • 지난 십년까지 상업화가 승인된 GM작물들의 특성을 보면 첫 단계에는 제초제저항성, 해충저항성, 바이러스 저항성 유전자가 도입된 작물 등으로 농업적 생산성을 증가시키기 위한 단일유전자가 도입된 것들이었으나 최근 들어 지방산 조성을 변경하거나, 특정 필수아미노산의 함량을 증가시키거나, 또는 화색을 변경 시킨 제 2세대 GM식물들의 승인건수가 점차 증가하는 추세에 있다. 뿐만 아니라, 현재 국가별로 심사 중에 있거나 환경위해성 평가용 자료를 생산하기 위하여 제한된 구역에서 포장시험을 수행하고 있는 것으로 알려진 GM 작물들을 보면 가뭄, 냉해 등에 내성이 강한 무생물적 스트레스 내성 작물, 녹색 성장의 주역이 될 biomass 증가, 또는 바이오디젤연료 생산 작물, 그리고 각종 의료용 및 산용 특수물질을 생산하는 분자농업용 작물 등이 주를 이루고 있는 것으로 조사되었다. 또한 아직은 실험실 또는 연구실 수준에서 성공하여 전문 학술지 또는 다양한 언론매체를 통하여 보도된 자료들을 분석한 결과에서도 이러한 차세대 GM 작물들의 개발건수가 현저하게 증가하고 있다. 특히 분자농업용 GM작물의 개발 건수가 가장 많은 것으로 조사되었다. 국내의 경우에도 비슷한 추세로 다양한 연구과제가 진행 중에 있는 것으로 조사되었으며. 국내에서 개발되어 최초로 환경위해성 평가를 신청한 GM 작물은 제초제 저항성잔디로서 현재까지 심사가 진행 중에 있으며, 이외에도 향후 신청을 위하여 포장시험이 진행 중에 있는 GM 작물들이 벼, 고추, 배추 등 약 10여종으로 이들 중 벼에 관한 건수가 가장 많았으며 그 중에서도 흑명나방 저항성 벼가 가장 많은 연구가 진행되어 곧 환경 위해성 평가를 신청할 것으로 조사되었다.

저층수 배사관 내 유입된 사석 배출능력에 대한 연구 (A Experimental Study on Exclusion Ability of Riprap into Bypass Pipe)

  • 정석일;이승오
    • 대한토목학회논문집
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    • 제37권1호
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    • pp.239-246
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    • 2017
  • 국내 중소하천의 횡단구조물인 보 또는 낙차공은 대부분 고정식 콘크리트 구조물이며, 저층수의 배제가 쉽지 않다. 횡단구조물로 인해 유사가 퇴적되며, 유사에 흡착한 오염물들이 그대로 하천의 바닥을 오염시키고 있다. 이에 저층수 및 퇴적유사에 대한 관심이 증가하고 있는 실정이며, 이러한 대안의 하나로 횡단구조물 상류와 하류를 하상 아래로 연결시키는 구조물로써, 보 상류 저층의 물 및 유사 배제를 목적으로 저층수배출관을 설치하는 방안이 있다. 그러나 사석이 유입되고, 배제 되지 않을 경우 효율성이 크게 저하될 가능성이 있다. 이에 본 연구에서는 저층수 배출관 내 사석을 배제할 수 있는 능력에 대한 연구를 수행하였다. 사석과 거동이 유사한 유사(sediment)의 한계조건(critical condition) 중 한계전단력(critical shear stress) 유도과정과 달랑베르의 원리(d'Alembert principle)를 응용하여 이동 중인 사석이 배제될 수 있는 조건(${\tau}_c{^*}$)을 유도하였다. 그러나 저층수 배출관 내 유입된 사석은 정지상태가 아닌 이동 중이므로, Lagrangian 기법을 활용하여 수리실험에서 도출된 유속으로 상대속도(relative velocity)를 제시하였다. 수리실험은 축척효과(scale effect)를 최소화하기 위해 폭이 5.0 m이고, 높이가 1.0 m인 광폭 개수로를 제작하였으며, 사용된 사석은 가공된 완전 구형을 사용하였다. 실험 결과 유속과 구형 입자 속도와의 비가 0.5~0.7 사이로 나타났으며, 이러한 결과를 유도된 식에 적용하여, 최종적으로 사석이 배제되는 조건을 도출하게 되었다. 구간은 입자레이놀즈수($Re_p$)와 무차원 한계 전단력(${\tau}_c{^*}$)에 따라 크게 3가지로 구분되었다. 배제 구간(exclusion section), 확률적 배제 구간(probabilistic exclusion section), 비배제 구간(no exclusion section)이다. 본 연구결과는 횡단구조물의 저층수 배출관 설계시 유용한 기초 정보를 제공할 수 있을 것이다.

수학영재의 특성에 관한 사례연구 (A Case Study on Characteristics of the Mathematics Gifted Children)

  • 김민정;류성림
    • 한국수학교육학회지시리즈C:초등수학교육
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    • 제10권1호
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    • pp.41-56
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    • 2007
  • 본 연구는 수학 영재에게서 나타나는 특성을 알아보기 위한 목적으로 초등학교 6학년에 재학 중이며 영재교육원에 다니고 있는 2명의 수학 영재를 약 4개월에 걸쳐 관찰 및 면접한 결과를 분석한 사례연구이다. 본 연구에서는 수학 영재의 특성을 입학하기 전, 일반 수업 시간, 방과 후로 나누어 그들이 보여준 주된 특성을 기술하고 있다. 본 논문을 통해 수학 영재가 그들의 자질을 잘 발휘하도록 하기 위해서 영재교육원, 일반 학급, 가정에서 어떻게 지도해야 할지에 대한 시사점을 주게 된다.

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농촌 농특산품 전시판매시설 디자인 소비자 의식 분석 및 디자인 개발 - 농촌관광마을을 중심으로 - (An Analysis on Consumers' Awareness of a Rural Specialties Exhibition Shop and the Design Development : Focusing on Rural Tourism Village)

  • 진혜련;서지예;조록환
    • 농촌계획
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    • 제20권4호
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    • pp.253-262
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    • 2014
  • This, an association research for design-improvement and model-development of exhibition shops at rural tourism communities, is to secure objective data by analyzing customers' awareness-tendency of and demand for agricultural-specialty exhibition shops. Survey-questions for finding out consumers' awareness-tendency and demand were determined through brainstorming of a professional council, 30 rural communities of which visit-rate by consumers is considerably high were selected for the recruit of 200 consumers. For investigation and analysis, survey and in-depth interview were carried out at the scene with the application of frequency analysis and summarization of their opinions, which revealed that they have a strong will to visit the rural tourism communities for the purchase of agricultural specialties along with the experience of learning-program and on-the-scene direct dealing and that their viewpoint on the direct dealing at the scene was very positive. Also it was confirmed hat their satisfaction with the purchase of agricultural specialties by on-the-scene direct dealing, their pleasure at the purchase, their satisfaction with services and their intention for re-purchase of them were very high while their satisfaction with the exhibition shops was very low. With on-the-scene survey, the consumers' opinions could be listened to in depth. Almost all of them said their satisfaction with the trip to those rural tourism communities was considerably high since they could go to those communities themselves to relieve the stress from their modern life, to experience healing and to see the goods on the scene. Their satisfaction also was attributed to the fact that they have enough trust in purchase along with feeling the warm-heartedness of rural residents. As to their awareness of exhibition shops, they showed a positive response to the on-the-scene direct dealing at rural communities while they, thinking that the space in those exhibition shops was not sufficiently wide, demanded for more systematic counters in more accessible and affordable exhibition shops so that they might be more satisfied with the exhibition shops. Their demand for the necessity of exhibition shops selling agricultural specialties was found to be over 80%, which indicates that the necessity is very high. As to the suitability of function, they have the opinion that the business at those shops had better be focused on sales since they have the understanding of information when they take a trip to the rural communities, while there was another opinion: since agricultural products are seasonal items they should be exhibited and sold at the same time. More than 90% of the respondents had a positive viewpoint on direct dealing of agricultural specialties on the scene, which showed that their response to it was very high. They preferred the permanent shops equipped with roll-around table-booths. In addition, it was revealed that they want systematic exhibition shops in rural communities because they frequent those communities for on-the-scene direct purchase. The preferred type and opinion resulting from estimation of consumers' demands have been reflected for development of practical designs. The structure of variable principles has been designed so that the types of display-case and table-booth might be created. The result of this study is a positive data as a design model which can be utilized at rural communities and will be commercialized for the verification of its validity.