• 제목/요약/키워드: Air Mass(AM)

검색결과 18건 처리시간 0.025초

가속기 질량 분광분석법을 이용한 대기 환경 연구 (Accelerator Mass Spectrometry in Atmospheric Environment)

  • 문창범;채수조;정준오;정진도
    • 한국대기환경학회:학술대회논문집
    • /
    • 한국대기환경학회 1999년도 추계학술대회 논문집
    • /
    • pp.103-107
    • /
    • 1999
  • 가속기 질량분광분석법(Accelerator Mass Spectrometry; AMS)은 동위원소 분석에 있어 초정밀 질량 분석 기술에 속한다. 시료(Samples)의 원자를 이온화 시켜 가속시키고, 에너지, 운동량 그리고 전하 상태를 분석하여 최종 얻고자 하는 원자핵의 동위원소, 예를 들어 탄소-14$^{14)C$),의 수를 정확하게 측정하는 분광분석 기술이다. 본 논문을 통하여 AMS를 소개하고 대기 환경 연구에 AMS가 어떻게 응용될 수 있는지 살펴 보기로 한다.(중략)

  • PDF

A Study on the Effects of System Pressure on Heat and Mass Transfer Rates of an Air Cooler

  • Jung, Hyung-Ho
    • Journal of Mechanical Science and Technology
    • /
    • 제16권5호
    • /
    • pp.696-702
    • /
    • 2002
  • In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychrometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements.

Highly efficient, long living white PIN-OLEDs for AM displays

  • Murano, Sven;Vehse, Martin;He, Gufeng;Birnstock, Jan;Hofmann, Michael
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
    • /
    • pp.239-244
    • /
    • 2007
  • Highly efficient and stable white PIN OLED structures have been developed with a focus on possible AM display applications. Due to the use of the novel air-stable Novaled n-dopant material NDN26, the mass production compatibility of the PIN approach is improved. With both a conventional n-dopant, NDN1, and a novel air-stable n-dopant, NDN26, similar performance in efficiency and lifetime are reached. Based on highly a stable red fluorescent emitter system, the Novaled PIN approach allows for reaching ultra-long lifetimes of 1,000,000 hours at a brightness of $1,000\;cd/m^2$, both for top and for bottom emission layouts. Furthermore, inverted PIN structures for a possible use in a-Si backplane applications for AM displays are shown. With a phosphorescent green emitter system it could be demonstrated that for bottom and inverted as well as non-inverted top emission, a brightness of $1,000\;cd/m^2$ can be reached at below 3 V. In addition to low operating voltages and long lifetimes, PIN OLEDs also enable for device structures with extremely low operating voltage drifts, a feature of increasing importance for future AM display developments.

  • PDF

Spray pyrolysis 방법에 의한 넓은 면적의 $Cu_2$S/CdS 태양전지의 제작 (Fabrication of large scale $Cu_2$S/CdS solar cells prepared by spray pyrolysis)

  • 차덕준;고정곤;정상조;남승재;김광윤;전용기
    • 한국진공학회지
    • /
    • 제5권4호
    • /
    • pp.341-347
    • /
    • 1996
  • Spray pyrolysis 방법으로 넓은 면적의 $Cu_2S$/CdS 태양전지를 제작하였다. 제작과정에서 전극형성, CdS spray 온도조건, $Cu_2S$층의 접합 조건등 태양전지의 효율에 영향을 주는 요인을 조사하였다. CdS 박막의 조건은 주사 전자현미경, X-선 회절기, 온도변화에 따른 광흡수 및 관전도 특성등을 통해 결정하였다. 1$\textrm{cm}^2$의 면적의 전지에 air mass 2(AM2)인 75mW/$\textrm{cm}^2$로 빛을 조사했을 때 3.15%의 효율을 얻었다.

  • PDF

결정질과 비정질 PV모듈의 자연광 스펙트럼에 따른 Isc의 변화 (Transition of Isc according to Natural Solar Spectrum on c-Si and a-Si PV Module)

  • 공지현;지양근;강기환;유권종;안형근;한득영
    • 한국태양에너지학회:학술대회논문집
    • /
    • 한국태양에너지학회 2009년도 추계학술발표대회 논문집
    • /
    • pp.86-91
    • /
    • 2009
  • In this paper, we analyze the Transition of Isc by natural solar spectrum of c-Si and a-Si PV module. Commonly, performance of photovoltaic (PV) module is estimated under the standard test condition (STC). That is, solar irradiance $1kW/m^2$, solar spectrum distribution: AM1 5G, module temperature $25^{\circ}C$ This means it rarely meets actual outdoor conditions. The solar spectrum always changes. So it is rare to fit the standard solar spectrum AM1 5G defined in ASTM G173-03 or IEC 60904-3. Thus spectral response of PV module is different depending on the material. so we estimated the variation of Isc at every minutes by comparing c-Si PV module with a-si PV module for outdoor conditions.

  • PDF

Novel Organic Electron Injectors for the Enhancement of Lifetime, Efficiency and Reduction in Operating Voltage in OLEDs

  • Kathirgamanathan, Poopathy;Arkley, Vincent;Surendrakumar, S.;Paramaswara, G.;Ganeshamurugan, S.;Antipan-Lara, J.;Ravichandran, S.;Kumaraverl, M.;Chan, Y.F.
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
    • /
    • pp.1206-1209
    • /
    • 2007
  • Both PM-OLEDs and AM-OLEDs are now in production. However, manufacturers are still concerned about life-time, voltage drift, operating voltage and efficiency in order to develop larger displays. Most material suppliers seem to be focussing on emitters and the benefits of introducing suitable charge transporters have been largely unexplored. OLED-T has developed a novel organic electron injector (Trade Name: EI-101) which evaporates at a very low temperature of $300^{\circ}C$ as opposed to the conventional LiF which requires $580^{\circ}C$. EI-101 has been found to increase the lifetime by up to 12%, reduce the voltage drift by up to 61% and increase the efficiency by up to 15%. The material can be handled in air and in situ Q-mass spectroscopy on extended thermal evaporation has confirmed its high stability for use in mass production.

  • PDF

Properties of Indoor Particles Collected in Japanese Homes

  • Ma, Chang-Jin;Kang, Gong-Unn;Kang, Chang-Hee
    • Asian Journal of Atmospheric Environment
    • /
    • 제9권1호
    • /
    • pp.31-38
    • /
    • 2015
  • Due to the heightened ambient $PM_{2.5}$ levels, the whole citizen of Japan, especially dwellers in Fukuoka Prefecture, start to make attention to the particulate matter (PM) of indoor environments. This study was aimed to thoroughly estimate the characteristics of indoor PM collected in five Japanese homes located in Fukuoka Prefecture. Simultaneous indoor measurements of PM were intensively made at five homes using filter-pack samplers, particle counters, and $PM_{2.5}$ monitors for a day in springtime, 2012. Major ionic and carbonaceous components were also analyzed. The time series fluctuation of PM number concentration was gradually decreased by 6 AM and then it was rapidly increased by 8 AM in all indoor sites. The maximum level of $PM_{2.5}$ was measured at the morning time (8 AM-9 AM) when the resident's behavior was fast and strenuous. The Indoor/Out-door (I/O) ratio for the giant PM larger than $5.0{\mu}m$ was 1.16. It was possible to identify PM types and estimate the resident's behavior through the comparison the theoretically calculated and the measured retention times for several types of PM in an indoor site. The theoretically reconstructed mass concentration of $PM_{2.0-0.3}$ suggested that the portion of $PM_{2.5}$ in indoor was quietly occupied by $PM_{0.3}$ or the PM inherently originated from indoor environment.

Si 태양전지에서 SiO2 광반사 방지막의 처리 효과 (Effect of SiO2 Antireflection Coating on the Si Solar Cell)

  • 장지근;임용규;황용운;조재욱
    • 한국재료학회지
    • /
    • 제14권2호
    • /
    • pp.152-156
    • /
    • 2004
  • We have studied the effective optical absorption power of Si solar cell with $SiO_2$-antireflection layer based on a mathematical modelling of AM(air mass)1 spectrum and Si refractive index in the wavelength range(0.4 $\mu\textrm{m}\leq$λ$\leq$$0.97\mu\textrm{m}$). The effective optical absorption power obtained from the theoretical calculation was 450 and 520 W/$\m^2$ for the Si solar cells with $SiO_2$-antireflection layer of 500$\AA$ and 1000$\AA$, respectively. The optimum thickness of $SiO_2$-antireflection layer showing the minimum reflection loss was about 1000$\AA$ in the computer simulation. Two kinds of Si solar cells named EBS(500$\AA$) and EBS(l000$\AA$) were fabricated to evaluate the effect of $SiO_2$-antireflection layer thickness on the optical absorption. The epitaxial base Si cell with $SiO_2$-antireflection layer of 1000$\AA$ [EBS(l000$\AA$)] showed the output power improvement of about 15% upon the EBS(500$\AA$) cell due to larger absorption of effective optical power under illumination of AM1, 1 sun.

Computations of Compressible Two-phase Flow using Accurate and Efficient Numerical Schemes

  • Kim, Chong-Am
    • 한국전산유체공학회:학술대회논문집
    • /
    • 한국전산유체공학회 2006년도 추계 학술대회논문집
    • /
    • pp.13-17
    • /
    • 2006
  • RoeM and AUSMPW+ schemes are two of the most accurate and efficient schemes which are recently developed for the analysis of single phase gas dynamics. In this paper, we developed two-phase versions of these schemes for the analysis of gas-liquid large density ratio two-phase flow. We adopt homogeneous equilibrium model (HEM) using mass fraction to describe different two phases. In the Eulerian-Eulerian framework, HEM assumes dynamic and thermal equilibrium of the two phases in the same computational mesh. From the mixture equation of state (EOS), we derived new shock-discontinuity sensing term (SDST), which is commonly used in RoeM and AUSMPW+ for the stable numerical flux calculation. The proposed two-phase versions of RoeM and AUSMPW+ schemes are applied on several air-water two-phase test problems. In spite of the large discrepancy of material properties such as density, enthalpy, and speed of sound, the numerical results show that both schemes provide very satisfactory solutions.

  • PDF

PERL (passivated emitter and rear locally-diffused cell) 방식을 이용한 고효율 Si 태양전지의 제작 및 특성 (Fabrication and Characteristics of High Efficiency Silicon PERL (passivated emitter and rear locally-diffused cell) Solar Cells)

  • 권오준;정훈;남기홍;김영우;배승춘;박성근;권성렬;김우현;김기완
    • 센서학회지
    • /
    • 제8권3호
    • /
    • pp.283-290
    • /
    • 1999
  • 본 연구에서는 고효율 단결정 실리콘 태양전지의 제작방법인 PERL방식을 사용하여 비저항이 $0.1{\sim}2{\Omega}{\cdot}cm$을 갖는 (100)면의 p형실리콘 기판으로 $n^+/p/p^+$ 접합의 태양전지를 제작하였다. 이를 위해 웨이퍼의 절단, KOH을 사용한 역피라미드 모양으로의 에칭, 인과붕소의 도핑, 반사방지막과 전극의 증착 및 열처리 등의 공정을 행하였다. 이때 소자표면의 광학적인 특성과 도핑농도가 저항값에 미치는 영향을 조사하고, Silvaco로 $n^+$도핑에 대한 확산 깊이와 도핑농도를 시뮬레이션하여 측정치와 비교하였다. AM(air mass) 1.5 조건하에서 입사되는 빛의 세기가 $100\;mW/cm^2$인 경우의 단락전류는 43 mA, 개방전압은 0.6 V, 그리고 충실도는 0.62였다. 이때 제작된 태양전지의 광전변환효율은 16%였다.

  • PDF