• 제목/요약/키워드: scale down

검색결과 840건 처리시간 0.032초

PIV를 이용한 실차 내부 환기유동의 정량적 속도장 측정 (PIV Measurements of Ventilation Flow inside a Passenger Compartment)

  • 이진평;이상준
    • 한국가시화정보학회지
    • /
    • 제9권3호
    • /
    • pp.24-29
    • /
    • 2011
  • The improvement of climatic comfort is crucial not only for passenger comfort but also for driving safety. Therefore, a better understanding on the flow characteristics of ventilation flow inside the passenger compartment is essential. Most of the previous studies investigated the ventilation flow using Computational Fluid Dynamics (CFD) calculations or scale-down water-model experiments. In this study, the ventilation flow inside the passenger compartment of a real commercial automobile was investigated using a Particle Image Velocimetry (PIV) velocity field measurement technique. Under real operating conditions, the velocity fields were measured at several vertical planes for several ventilation modes. The experimental data obtained from this study can be used to understand the detailed flow characteristics in the passenger compartment of a real car and to validate numerical predictions.

50m급 무인비행선 시험비행 안전성 요구사항에 관한 연구 (A study on Requirements of the Test Flight Safety for a 350m Unmanned Airship)

  • 정봉구;신대원
    • 한국항공운항학회지
    • /
    • 제12권2호
    • /
    • pp.1-15
    • /
    • 2004
  • In this study, we analyze technical requirements for a 50m unmanned airship order to assure safety in the test flight operation. The 50m class unmanned airship developed by Airship Group in Korea Aerospace Research Institute(KARI). The 50m class unmanned airship was developed as a scale-down model of 200m class stratosphere unmanned airship. This study reviews specifications and characteristics of 50m class unmanned airship and develops Airworthiness Requirements on the basis of current effective Aviation Act, Airworthiness standards, and relevant international documents. The developed requirements can be applied to the safety assessment of the 200m class stratosphere unmanned airship.

  • PDF

어패류의 비브리오패혈증 균 오염과 그 대책 (Contamination of Shellfish with Vibrio vulnificus the Present Situation and Countermeasures)

  • 김영만
    • 한국식품위생안전성학회지
    • /
    • 제8권2호
    • /
    • pp.13-21
    • /
    • 1993
  • Vibrio septicemia,, resulting in high mortality, has been caused by Vibrio vulnificus. Ingestion of marine products or contact with sea water contaminated with Vibrio vulnificus can cause septicemia. Vibrio vulnificus has been detected world wide and west sea area of Korea, Kum river estuary in particular, showed high detection rate. Higher detection rate of Vibrio vulnificus were reported in the bottom deposit with low depth of water, low salinity, and high COD. Man with the liver disease can easily come down with Vibrio septicemia and the main source is the sliced raw fish dish. The preventive measure for this disease is to wash raw fish material thoroughly with tap water and handle in sanitary conditions. Washing with sea water is strictly prohibited . It may be necessary to forbid the small-scale businessmen from selling the sliced ray fish dish in the vicinity of seashore. Man with the liver disease of diabetes should not swim or consume the raw fish dish in the contaminated area during summer.

  • PDF

극초단 레이저를 이용한 PCL 및 PET 가공에 대한 연구 (A Study of PCL and PET ablation by ultrashort laser)

  • 최해운;신현명
    • 한국레이저가공학회지
    • /
    • 제11권4호
    • /
    • pp.1-6
    • /
    • 2008
  • This paper describes microscale laser structuring of electrospun(ES) PCL and PET nanofiber meshes. Electrospinning produces non-woven meshes of synthetic or natural materials fibers with diameters ranging from micron down to the nanometer scales that are advantageous for the supporting the growth of the small scale structures. Ultrashort laser found to be effective on the fabrication of engineeredtissue scaffold with minimum heat affect and ultra precision ablation patterns. The affect of energy range for ablation quality was analyzed and ablation characteristics of PCL and PET were compared.

  • PDF

등가산화막두께 스케일링을 위한 다성분 산화막에 관한 연구 (Equivalent Oxide Thickness Scaling for Multi-Component Dielectric Thin Film)

  • 안지훈
    • 한국표면공학회:학술대회논문집
    • /
    • 한국표면공학회 2015년도 추계학술대회 논문집
    • /
    • pp.155-155
    • /
    • 2015
  • 메모리 반도체의 지속적인 scale down을 위해서는 고유전 산화막을 이용한 등가산화막두께(EOT) 스케일링이 이뤄져야 한다. 특히, DRAM의 커패시터의 경우, EOT scaling을 위한 신 물질 및 공정개발이 지연되면서 전극과 유전체 사이의 계면특성 개선, 또는 기존에 사용하던 물질을 지속적으로 사용할 수 있는 방안에 대한 필요성이 대두되고 있다. 본 발표에서는 DRAM 커패시터 소재 개발이 겪고 있는 어려움에 대해 소개하고 기존에 반도체 라인에서 사용하고 있는 물질들을 조합한 다성분계 산화막을 이용하여 EOT 0.5 nm를 구현하기 위한 연구 결과에 대해 보고한다. 또한 앞으로 지속적인 커패시터 유전체 개발을 위해 관심을 갖고 수행해야 하는 연구에 대해 함께 다룬다.

  • PDF

染色物의 日光에 對한 堅牟性에 關한 硏究 (第2報) 褪色速度 曲線에 對하여 (Studies on the Light Fastness of Dyeings. (II) Fading Rate Curve)

  • 하완식
    • 대한화학회지
    • /
    • 제8권4호
    • /
    • pp.142-146
    • /
    • 1964
  • The author proposed an equation of fading rate, expressed as ${\Delta}E$=${\Delta}E_{1{\infty}}({{1-e^{-k}}_1}^t)+k_2t$, where ${\Delta}E$=fading of dye (colour difference of N.B.S. unit), ${\Delta}E_{1{\infty}}$=extremity value of fading of molecularly dispersed dye, $k_1$, $k_2$=constants, t=exposure (hours). The validity of above equation, which is connected with the state of dye in fibre, was confirmed by experimental in a range of 2-3 colour fading in grey scale value for assessing change in colour visually, except the case of increasing the fading rate with the time resulted from the break-down of dye particles through the heat effect of light; it was also discussed about possiblity of evaluating of fastness to light of dye in early stage.

  • PDF

고효율 냉동 컨테이너의 냉각 및 제상 실험 (Experimental Study of a High Efficiency Transport Refrigeration Container under Cooling and Defrosting Conditions)

  • 문제철;;최광일;오종택
    • 대한설비공학회:학술대회논문집
    • /
    • 대한설비공학회 2008년도 하계학술발표대회 논문집
    • /
    • pp.277-281
    • /
    • 2008
  • This paper presents the development of a high efficiency transport refrigeration system for sliced-raw fish transportation. The refrigeration system is equipped with heat storage for reverse cycle-hot gas defrost (the stored heat is used during defrost cycle of the system). System performance and container operating conditions are analyzed during experimental investigation on a $3,225{\times}1,740{\times}1,640\;mm$ full-scale refrigerated container under cooling and defrosting conditions. The prototype system indicates better performance in terms of shorter cooling-down time, shorter defrost time and smaller fluctuations of refrigerated container's temperature.

  • PDF

약국실무실습에 대한 약학대학 재학생 인식 (The Perception of Pharmacy Students on the Educational Clerkship in Community Pharmacies: An Exploratory Study for the New Pharmacy Curriculum)

  • 김성은;조은;정규혁
    • 약학회지
    • /
    • 제55권3호
    • /
    • pp.219-226
    • /
    • 2011
  • This study aimed to understand the perception of pharmacy students (n=92) toward educational clerkship in community pharmaciese. The survey results showed that students perceived the need for clinical pharmacy practice-focused education. Students had a strict criterion for the eligibility of preceptors and a strong preference toward a large scale of hospital-nearby pharmacies for a practice site. Students with a previous training experience tended to hold negative opinions on the necessity of practice guidelines. To settle down community pharmacy practice system, students' needs and expectations should be considered.

U-중차량 무인과적 단속시스템 구현을 위한 WIM Sensor 산정에 관한 연구 (A Study on Determination of WIM Sensor for Implementation of U-Overloaded Vehicle Regulation System)

  • 최해윤;장정희;조병완;윤석민;오영국;이규완
    • 한국전산구조공학회:학술대회논문집
    • /
    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
    • /
    • pp.825-830
    • /
    • 2007
  • For the design and maintenance of highways and road structures, the statistical data are needed for the vehicle, especially heavy truck crossing. So far, static weighing has been used but it needs fixed station, crews, and it takes a lot of time. Also truck mix and headway distances cannot be obtained. Weigh-In-Motion system uses the sensor as a weighing scale and collects the axle weights, axle distances, vehicle types and etc. without stopping or slowing down the vehicle. Objectives of the study is make a determination of WIM Sensor for Implementation of U-Overloaded Vehicle Regulation System.

  • PDF

MC-DCT영역에서의 효율적인 비디오 축소 방법 (An Efficient Video Scale-Down Method on MC-DCT Domain)

  • 이승철;이화순;낭종호
    • 한국정보과학회:학술대회논문집
    • /
    • 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
    • /
    • pp.445-447
    • /
    • 2004
  • 본 논문에서는 H.263과 같은 MC-DCT방법을 사용하는 코덱에서 IDCT와 MC(Motion Compensation, 움직임보상)방법을 부분적으로 수정하여 제한된 비율의 축소영상을 디코딩 과정에서 직접 얻을 수 있는 방법을 제안한다. 제안한 방법에서는 8$\times$8 DCT 블록에 대하여 약간의 연산을 가하여 k$\times$k IDCT를 수행하고, 시간적 중복성을 제거하는 과정에서 근사적 움직임벡터를 이용한 2k$\times$2k MC 를 수행하였다. 기존의 코덱을 사용하고 후처리로 축소를 하는 경우와 비교하였을 때에 추가적인 오버헤드가 매우 경미하고 디코딩 과정이 많이 축소되어 계산효율에 있어서 대략 32%의 개선된 실험결과를 얻었고, 화질저하 현상이 개선됨을 실험적으로 보였다.

  • PDF