• 제목/요약/키워드: Atmospheric physics

검색결과 276건 처리시간 0.028초

Interaction among the East Asian Summer and Winter Monsoons, the Tropical Western Pacific and ENSO Cycle

  • Huang, Rong-Hui;Lu, Ri-Yu;Chen, Wen;Chen, Ji-Rong
    • 대기
    • /
    • 제13권2호
    • /
    • pp.47-68
    • /
    • 2003
  • Recent advances in the studies on the interaction between Asian monsoon and ENSO cycle are reviewed in this paper. Through the recent studies, the East Asian summer monsoon circulation system and the East Asian climate system have proposed. Moreover, different responses of the (winter and summer) monsoon circulation and summer rainfall anomalies in East Asia to ENSO cycle during its different stages have been understood further. Recently, the studies on the dynamical effect of East Asian monsoon on the thermal variability of the tropical western Pacific and ENSO cycle have been greatly advanced. These studies demonstrated further that ENSO cycle originates from the tropical western Pacific, and pointed out that the dynamical effect of East Asian winter and summer monsoons on ENSO cycle may be through the atmospheric circulation and zonal wind anomalies over the tropical western Pacific, which can excite the oceanic Kelvin wave and Rossby waves in the equatorial Pacific. Besides, the scientific problems in the interaction between Asian monsoon and ENSO cycle, which should be studied further in the near future, are also pointed out in this paper.

전구 모델의 물리과정에 따른 태풍 모의 민감도 (Sensitivity of Typhoon Simulation to Physics Parameterizations in the Global Model)

  • 김기병;이은희;설경희
    • 대기
    • /
    • 제27권1호
    • /
    • pp.17-28
    • /
    • 2017
  • The sensitivity of the typhoon track and intensity simulation to physics schemes of the global model are examined for the typhoon Bolaven and Tembin cases by using the Global/Regional Integrated Model System-Global Model Program (GRIMs-GMP) with the physics package version 2.0 of the Korea Institute of Atmospheric Prediction Systems. Microphysics, Cloudiness, and Planetary boundary Layer (PBL) parameterizations are changed and the impact of each scheme change to typhoon simulation is compared with the control simulation and observation. It is found that change of microphysics scheme from WRF Single-Moment 5-class (WSM5) to 1-class (WSM1) affects to the typhoon simulation significantly, showing the intensified typhoon activity and increased precipitation amount, while the effect of the prognostic cloudiness and PBL enhanced mixing scheme is not noticeable. It appears that WSM1 simulates relatively unstable and drier atmospheric structure than WSM5, which is induced by the latent heat change and the associated radiative effect due to not considering ice cloud. And WSM1 results the enhanced typhoon intensity and heavy rainfall simulation. It suggests that the microphysics is important to improve the capability for typhoon simulation of a global model and to increase the predictability of medium range forecast.

Understanding of Non-Thermal Atmospheric Pressure Plasma Characteristics Produced in Parallel Plate Type Geometry

  • Choe, Wonho;Moon, Se Youn;Kim, Dan Bee;Jung, Heesoo;Rhee, Jun Kyu;Gweon, Bomi
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
    • /
    • pp.144-144
    • /
    • 2013
  • Non-thermal atmospheric pressure plasmas have recently garnered much attention due to their unique physical and chemical properties that are sometimes significantly different from those of low pressure plasmas. It can offer many possible application areas including nano and bio/medical areas. Many different types of plasma sources have been developed for specific needs, which can be one of the important merits of the atmospheric pressure plasmas since characteristics of the produced plasma depend significantly on operating parameters such as driving frequency, supply gas type, driving voltage waveform, gas flow rate, gas composition, geometrical factor etc. Among many source configurations, parallel plate type geometry is one of the simplest configurations so that it can offer many insights for understanding basic underlying physics. Traditionally, the parallel plate type set up has been studied actively for understanding low pressure plasma physics along with extensive employment in industries for the same reason. By considering that understanding basic physics, in conjunction with plasma-surface interactions especially for nano & bio materials, should be pursued in parallel with applications, we investigated atmospheric pressure discharge characteristics in a parallel plate type capacitive discharge source with two parallel copper electrodes of 60 mm in diameter and several millimeters in gap distance. In this presentation, some plasma characteristics by varying many operating variables such as inter-electrode distance, gas pressure, gas composition, driving frequency etc will be discussed. The results may be utilized for plasma control for widening application flexibility.

  • PDF

p-n 접합 형성을 위한 반도체 실리콘 웨이퍼 대기압 플라즈마 붕소 확산 가능성 연구 (Study of Boron Doping Feasibility with Atmospheric Pressure Plasma for p-n Junction Formation on Silicon Wafer for Semiconductor)

  • 김우재;이환희;권희태;신기원;양창실;권기청
    • 반도체디스플레이기술학회지
    • /
    • 제16권4호
    • /
    • pp.20-24
    • /
    • 2017
  • Currently, techniques mainly used in semiconductor impurity diffusion processes include furnace thermal diffusion, ion implantation, and vacuum plasma doping. However, there is a disadvantage that the process equipment and the unit cost are expensive. In this study, boron diffusion process using relatively inexpensive atmospheric plasma was conducted to solve this problem. With controlling parameters of Boron diffusion process, the doping characteristics were analyzed by using secondary ion mass spectrometry. As a result, the influence of each variable in the doping process was analyzed and the feasibility of atmospheric plasma doping was confirmed.

  • PDF

Room-Temperature Luminescence from Ion Beam or Atmospheric Pressure Plasma-Treated SrTiO3

  • Song, J.H.;Choi, J.M.;Cho, M.H.;Choi, E.J.;Kim, J.;Song, J.H.
    • Applied Science and Convergence Technology
    • /
    • 제23권5호
    • /
    • pp.261-264
    • /
    • 2014
  • $SrTiO_3$ (STO) single crystal irradiated with a 3-MeV proton beam exhibits blue and green mixed luminescence. However, the same proton beam when used to irradiate STO with a very thin layer of deposited Pt does not show any luminescence. This Pt layer prevents any damage which may otherwise be caused by arcing, which stems from the accumulated surface voltage of tens of kV due to the charge induced by secondary electrons on the surface of the insulator during the ion beam irradiation process. Hence, the luminescence of ion-irradiated STO originates from the modification of the STO surface layer caused by arcing rather than from any direct ion beam irradiation effect. STO treated with atmospheric-pressure plasma, a simple and cost-effective method, also exhibits the same type of blue and green mixed luminescence as STO treated with an ion beam, as the plasma also creates a layer of surface damage due to arcing.

Effects of OH Radical Density from Atmospheric Plasma to Induce Cell Death in Lung Cancer and Normal Cells

  • 박대훈;김용희;심건보;백구연;엄환섭;최은하
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
    • /
    • pp.254.1-254.1
    • /
    • 2014
  • Atmospheric plasma's electron temperature is less than thermal plasma, so it is useful at bio experiment. We have investigated the optical emission spectroscopy (OES) lines by spectrometer during Atmospheric plasma bombardment onto the PBS surface by using an Ar gas flow. Also we have measured the OH radical density inside the solution induced by the Atmospheric plasma bombardment. OH radical species are appeared at 308 nm and 309 nm. Densities of OH radical species has been found to be significantly decreased versus depth of the solution from 2 mm to 6 mm. OH radical density inside the PBS is measured to be about $1.87{\times}1016cm-3$ downstream at 2 mm from the surface under optimized Ar gas flow of 200 sccm in Atmospheric plasma. Also we have investigated cell viability of lung cancer and normal cell after Atmospheric plasma treatment for fixed exposure time in 60 seconds, but different depths. We used SEM, we observed change of cell morphorogy, did experiment about FDA & PI Staining method. It is found that there is selectivity between the lung cancer and lung normal cell, in which cancer cell definitely has higher cell death ratio more than normal cell. We have investigated change of bond structure in FT-IR spectroscopy, the following peaks were observed: and intense O-H peak at 3422 cm-1 and at 2925 cm-1 corresponds to C-H stretch vibrations of methylene group.

  • PDF

Nudging of Vertical Profiles of Meteorological Parameters in One-Dimensional Atmospheric Model: A Step Towards Improvements in Numerical Simulations

  • Subrahamanyam, D. Bala;Rani, S. Indira;Ramachandran, Radhika;Kunhikrishnan, P. K.
    • Ocean Science Journal
    • /
    • 제43권4호
    • /
    • pp.165-173
    • /
    • 2008
  • In this article, we describe a simple yet effective method for insertion of observational datasets in a mesoscale atmospheric model used in one-dimensional configuration through Nudging. To demonstrate the effectiveness of this technique, vertical profiles of meteorological parameters obtained from GLASS Sonde launches from a tiny island of Kaashidhoo in the Republic of Maldives are injected in a mesoscale atmospheric model - Advanced Regional Prediction System (ARPS), and model simulated parameters are compared with the available observational datasets. Analysis of one-time nudging in the model simulations over Kaashidhoo show that incorporation of this technique reasonably improves the model simulations within a time domain of +6 to +12 Hrs, while its impact on +18 Hrs simulations and beyond becomes literally null.

ELECTRON TEMPERATURE ESTIMATION OF NON-THERMAL ATMOSPHERIC-PRESSURE NEON AND OXYGEN ADMIXTURE PLASMA JET BY CONVECTIVE WAVE PACKET MODEL

  • SORNSAKDANUPHAP, Jirapong;SUANPOOT, Pradoong;Hong, Young June;Ghimire, Bhagirath;CHO, Guangsup;CHOI, EunHa
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
    • /
    • pp.207-207
    • /
    • 2016
  • plasma group velocities of neon with oxygen admixture (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities outside interelectrode region are in the order of 104 m/s.The plasma ambipolar diffusion velocities are calculated to be in the order of 102 m/s. Plasma jet is generated by all fixed sinusoidal power supply, total gas flow and repetition frequency at 3 kV, 800 sccm and 40 kHz, respectively. The amount of oxygen admixture is varied from 0 to 2.75 %. By employing one dimensional convective wave packet model, the electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be in a range from 1.65 to 1.95 eV.

  • PDF

ELECTRON TEMPERATURE ESTIMATION OF NON-THERMAL ATMOSPHERIC-PRESSURE NEON AND ARGON PLASMA JET BY CONVECTIVE WAVE PACKET MODEL

  • SORNSAKDANUPHAP, Jirapong;SUANPOOT, Pradoong;Hong, Young June;Ghimire, Bhagirath;CHO, Guangsup;CHOI, Eun Ha
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
    • /
    • pp.156.1-156.1
    • /
    • 2015
  • Neon and argon plasma group velocities (ug) are obtained by intensified charge coupled device (ICCD) camera images at fixed gate width time of 5 ns. The propagation velocities in upstream and downstream region are in the order of 104-105 m/s. The plasma ambipolar diffusion velocities are calculated to be in the order of 101-102 m/s. Plasma jet is generated by sinusoidal power supply in varying voltages from 1 to 4 kV at repetition frequency of 40 kHz. By employing one dimensional convective wave packet model, the neon and argon electron temperatures in non-thermal atmospheric-pressure plasma jet are estimated to be 1.95 and 1.18 eV, respectively.

  • PDF