• Title/Summary/Keyword: $CO_2$ Stripping

Search Result 88, Processing Time 0.022 seconds

A case study of extraplanar molecular gas in a Virgo spiral using the ALMA

  • Lee, Bumhyun;Chung, Aeree
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.41 no.2
    • /
    • pp.61.3-62
    • /
    • 2016
  • NGC 4522 is a spiral galaxy located in the Virgo cluster which appears to be undergoing active ram pressure stripping due to the intracluster medium (ICM). What makes this galaxy special is the extraplanar CO gas, some of which coincides with the extraplanar $H{\alpha}$ patches. As one of the few cases where the interstellar molecular gas is thought to have been pushed out from the stellar disk by the ICM, this galaxy provides an opportunity to study the impact of ICM pressure on the dense/star forming gas and its fate in the extraplanar space after stripping. In order to probe detailed molecular gas properties inside and outside the stellar disk and the associated star formation activities, we have observed NGC 4522 in 12CO (1-0) and 13CO (1-0) using the ALMA. We have targeted two regions, one around the center of the galaxy and one centered on the peak of the extraplanar CO, detecting both lines in both regions. Particularly, this is the first case where 13CO gas has been detected outside the stellar disk in a galaxy undergoing ram pressure stripping. In this work, we present preliminary results from the ALMA observations and discuss the evolution of molecular gas properties and star formation activities inside and outside the stellar disk.

  • PDF

Removal of Post Etch/Ash Residue on an Aluminum Patterned Wafer Using Supercritical CO2 Mixtures with Co-solvents and Surfactants: the Removal of Post Etch/Ash Residue on an Aluminum Patterned Wafer

  • You, Seong-sik
    • Journal of the Semiconductor & Display Technology
    • /
    • v.16 no.2
    • /
    • pp.55-60
    • /
    • 2017
  • The supercritical $CO_2$ (sc-$CO_2$) mixture and the sc-$CO_2$-based Photoresist(PR) stripping(SCPS) process were applied to the removal of the post etch/ash PR residue on aluminum patterned wafers and the results were observed by scanning of electron microscope(SEM). In the case of MDII wafers, the carbonized PR was able to be effectively removed without pre-stripping by oxygen plasma ashing by using sc-$CO_2$ mixture containing the optimum formulated additives at the proper pressure and temperature, and the same result was also able to be obtained in the case of HDII wafer. It was found that the efficiency of SCPS of ion implanted wafer improved as the temperature of SCPS was high, so a very large amount of MEA in the sc-$CO_2$ mixture could be reduced if the temperature could be increased at condition that a process permits, and the ion implanted photoresist(IIP) on the wafer was able to be removed completely without pre-treatment of plasma ashing by using the only 1 step SCPS process. By using SCPS process, PR polymers formed on sidewalls of metal conductive layers such as aluminum films, titanium and titanium nitride films by dry etching and ashing processes were removed effectively with the minimization of the corrosion of the metal conductive layers.

  • PDF

Efficient Stripping of High-dose Ion-implanted Photoresist in Supercritical Carbon Dioxide (초임계 이산화탄소를 이용한 고농도이온주입 포토레지스트의 효율적인 제거)

  • Kim, Do-Hoon;Lim, Eu-Sang;Lim, Kwon-Taek
    • Clean Technology
    • /
    • v.17 no.4
    • /
    • pp.300-305
    • /
    • 2011
  • A mixture of supercritical carbon dioxide and a co-solvent was employed to strip a high-dose ion-implanted photoresist (HDIPR) from the surface of semiconductor wafers. The stripping efficiency was highly improved by the physical force generated from a ultrasonication tip inside the reactor. In addition, helium gas was injected in the reactor as a barrier gas before the introduction of pure supercritical $CO_2$ ($scCO_2$), which reduced the rinsing time significantly. The effect of co-solvents on the stripping efficiency was investigated. The wafer surfaces were analyzed by scanning electron microscopy and by an energy dispersive X-ray spectrometer.

Deep Impact: Molecular Gas Properties under Strong Ram Pressure Probed by High-Resolution Radio Interferometric Observations

  • Lee, Bumhyun;Chun, Aeree
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.44 no.2
    • /
    • pp.39.3-39.3
    • /
    • 2019
  • Ram pressure stripping due to the intracluster medium (ICM) is an important environmental process, which causes star formation quenching by effectively removing cold interstellar gas from galaxies in dense environments. The evidence of diffuse atomic gas stripping has been reported in several HI imaging studies. However, it is still under debate whether molecular gas (i.e., a more direct ingredient for star formation) can be also affected and/or stripped by ram pressure. The goal of this thesis is to understand the impact of ram pressure on the molecular gas content of cluster galaxies and hence star formation activity. To achieve this, we conducted a series of detailed studies on the molecular gas properties of three Virgo spiral galaxies with clear signs of active HI gas stripping (NGC 4330, NGC 4402, and NGC 4522) based on high-resolution CO data obtained from the Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). As a result, we find the evidence that the molecular gas disk also gets affected by ram pressure in similar ways as HI even well inside of the stellar disk. In addition, we detected extraplanar 13CO clumps in one of the sample, which is the first case ever reported in ram pressure stripped galaxies. By analyzing multi-wavelength data (e.g., Hα, UV, HI, and CO), we discuss detailed processes of how ram pressure affects star formation activities and hence evolution of cluster galaxies. We also discuss the origin of extraplanar 13CO, and how ram pressure can potentially contribute to the chemical evolution of the ICM.

  • PDF

Effects of Gas Recycle on Plant Cell Growth and Secondary Metabolites Production in Airlift Fermentor (Airlift 배양기에서 Gas Recycle이 식물세포 성장 및 이차대사산물 생성에 미치는 영향)

  • 유병삼;변상요
    • KSBB Journal
    • /
    • v.9 no.2
    • /
    • pp.180-185
    • /
    • 1994
  • The productivity of alkaloid in the airlift fermentor operation was less than that of suspension coltures of Eschscholtzia californica cells in the shake flask. To overcome the productivity reduction, a gas recycle airlift fermentor was developed because the gas-stripping in normal airlift fermentor was believed to play a significant role for productivity reduction. The alkaloid content in the gas recycle system with Eschscholtzia californica suspension cells was 2.7 times higher than that of normal airlift fermentor. The productivity of alkaloids and $CO_2$ concentration were affected by the volume of gas reservoir in the gas recycle airlift fermentor.

  • PDF

Estimation of Ammonia Stripping Condition for Adequate Aerobic Liquid-Composting of Swine Manure (돈분뇨의 적합한 호기성 액비화를 위한 암모니아 탈기조건 설정)

  • Son, Bo-Kyoon;Gang, Seong-Gu;Jo, Eun-Ju;Kim, Shin-Do;Lee, Chang-Ju;Kim, Jeong-Ho
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.39 no.2
    • /
    • pp.73-79
    • /
    • 2006
  • Aeration is the most important and indispensable operation unit for the treatment of swine manure using aerobic liquid-composting process. The composting of swine manure depends on biological treatment process, but the highly concentrated ammonia nitrogen is required a pretreatment to expect the appropriate efficiency of the biological treatment process. In this study, pilot experiments have been carried out to estimate of the fit condition about ammonia stripping process as a pretreatment to aerobic liquid- composting. pH adjustment with $Ca(OH)_2$ was economically superior to use of NaOH and optimum pH of ammonia stripping was 12.3, ammonia nitorgen was rapidly removed as pH were increased at $$35^{\circ}C$$. When air stripping is performed before aerobic liquid-stripping, a high initial pH is required for complete ammonia removal and is additional effects such as organic substances, phosphorus, turbidity, and color removal. Stripping process was very efficient in the pretreatment of highly concentrated ammonia nitrogen for composting of swine manure. Emission rate of gaseous ammonia was $0.5355mole\;s^{-1}$ at initial time and $0.0253mole\;s^{-1}$ at finitial time. The fit condition of ammonia stripping in this study were at the temperature of $$35^{\circ}C$$, and the pH of 12.3 during 48 hours.

The ISM properties under ICM pressure in the cluster environment : NGC4330, NGC4402, NGC4522, NGC4569

  • Lee, Bumhyun;Chung, Aeree
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.37 no.2
    • /
    • pp.85.2-85.2
    • /
    • 2012
  • The interstellar medium (ISM) of galaxies in the galaxy cluster can well be affected by the intracluster medium (ICM). Among many suggested environmental processes, ram pressure stripping can effectively remove gas through the interaction with the ICM. In fact, Cluster galaxies are lower in HI gas mass compared to their field counterparts, and in recent high resolution HI imaging studies, many galaxies in dense environments have been found to be ram pressure stripped in HI. However, it is still under debate whether the ICM pressure can also remove dense molecular gas from the galactic disk, which plays more important role in star formation and hence galaxy evolution. To answer this question, we have obtained high resolution 12/13 CO (2-1) data from the Sub Millimeter Array (SMA) of four galaxies at various HI stripping stages to study how the molecular gas properties change as the galaxy experiences the ICM pressure. We investigate the physical properties of molecular gas with 12/13 CO images. By comparing with other wavelength data, i.e. data(optical, HI, $H{\alpha}$, etc), we discuss how and in which timescale galaxies can migrate from the blue cloud to the red sequence due to ram pressure stripping.

  • PDF

Li-free Thin-Film Batteries with Structural Configuration of Pt/LiCoO2/LiPON/Cu and Pt/LiCoO2/LiPON/LiCoO2/Cu (Pt/LiCoO2/LiPON/Cu와 Pt/LiCoO2/LiPON/LiCoO2/Cu 구조를 갖는 Li-free 박막전지)

  • Shin, Min-Seon;Kim, Tae-Yeon;Lee, Sung-Man
    • Journal of the Korean institute of surface engineering
    • /
    • v.51 no.4
    • /
    • pp.243-248
    • /
    • 2018
  • All solid state thin film batteries with two types of cell structure, Pt / $LiCoO_2$ / LiPON / Cu and Pt / $LiCoO_2$ / LiPON / $LiCoO_2$ / Cu, are prepared and their electrochemical performances are investigated to evaluate the effect of $LiCoO_2$ interlayer at the interface of LiPON / Cu. The crystallinity of the deposited $LiCoO_2$ thin films is confirmed by XRD and Raman analysis. The crystalline $LiCoO_2$ cathode thin film is obtained and $LiCoO_2$ as the interlayer appears to be amorphous. The surface morphology of Cu current collector after cycling of the batteries is observed by AFM. The presence of a 10 nm-thick layer of $LiCoO_2$ at the interface of LiPON / Cu enhances the interfacial adhesion and reduces the interfacial resistance. As a result, Li plating / stripping at the interface of LiPON / Cu during charge/discharge reaction takes place more uniformly on Cu current collector, while without the interlayer of $LiCoO_2$ at the interface of LiPON / Cu, the Li plating / stripping is localized on current collector. The thin film batteries with the interlayer of $LiCoO_2$ at the interface of LiPON / Cu exhibits enhanced initial coulombic efficiency, reversible capacity and cycling stability. The thickness of the anode current collector Cu also appears to be crucial for electrochemical performances of all solid state thin film batteries.