• Title/Summary/Keyword: Molecular ionization

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Characteristics of Low-power Microwave Induced Plasma Emission Spectrum and Detection of $CO_2$ (저출력 마이크로파 유도 플라스마 방출스펙트럼의 특성과 $CO_2$ 분석)

  • Noh, Seung Man;Park, Chang Joon;Kim, Young Sang
    • Journal of the Korean Chemical Society
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    • v.40 no.4
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    • pp.235-242
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    • 1996
  • A surfatron-type microwave induced plasma (MIP) cavity has been constructed, which can be easily interfaced with a gas chromatograph. Various plasma gases such as He, Ar and N2 were used to generate the MIP and small amounts of CO2 gases were injected through the MIP to obtain characteristic spectrum of each plasma gas and to study feasibility of the MIP as a soft ionization source. Since He and Ar plasmas have high metastable state energy, it was not possible to detect sample gas in molecular state. With N2 plasma, however, a strong emission of molecular ions could be detected owing to its low metastable state energy.

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Protein Patterns on a Corpus Luteum during Pregnancy in Korean Native Cows

  • Chung, Hak-Jae;You, Dong-Min;Kim, Hyo-Ju;Choi, Hye-Young;Lee, Myeong-Suk;Kim, Jin-Bum;Lee, Suck-Dong;Park, Jung-Yong;Lee, Myeung-Sik
    • Reproductive and Developmental Biology
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    • v.34 no.3
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    • pp.263-270
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    • 2010
  • Luteal cells produce progesterone that supports pregnancy. Steroidogenesis requires coordination of the anabolic and catabolic pathways of lipid metabolism. In the present study, the corpus luteum (CL) in early pregnancy established from luteal phase and pregnant phase was analyzed. The first study determined progesterone changes in the bovine CL at day 19 (early maternal recognition period) and day 90 in mid-pregnancy and compared them to the CL from day 12 of the estrous cycle. CL alternation was tested using two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF). Comparing CL from luteal phase to those from pregnant phase counterparts, significant changes in expression level were found in 23 proteins. Of these proteins 17 were not expressed in pregnant phase CL but expressed in luteal phase counterpart, whereas, the expression of the other 6 proteins was limited only in pregnant phase CL. Among these proteins, vimentin is considered to be involved in regulation of post-implantation development. In particular, vimentin may be used as marker for CL development during pregnancy because the expression level changed considerably in pregnant phase CL tissue compared with its luteal phase counterpart. Data from 2-DE suggest that protein expression was disorientated in mid pregnancy from luteal phase, but these changes was regulated with progression of pregnancy. These findings demonstrate CL development during mid-pregnancy from luteal phase and suggest that alternations of specific CL protein expression may be involved in maintenance of pregnancy.

Identification of Antimutagenic Compound from Kale by High Performance liquid Chromatography and Mass Spectrometry

  • Lee, Seon-Mi;Rhee, Sook -Hee;Yoo, Jong-Shin;Park, Kun-Young
    • Preventive Nutrition and Food Science
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    • v.3 no.4
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    • pp.334-338
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    • 1998
  • Kale(Brassica oleracea var. acephala) is one of Cruciferous vegetables that is closely related to the wild ancestral form of cabbabe. The ethanol extract of kale which contains the active compoundsss under Salmonella assay system was fractionated with chloroform to collect the nonpolar solvent soluble compounds, and then further fractionation was carried out by silica gel column chromatography. Among kale extracts separated by silical gel column chromatography, the fractions of 4, 5 and 6 exhibited strong antimutagenic activities. The major active compounds from the fraction were identified as chlorophyll derivatives by the analysis with HPLC-fritp-MS. The molecular weights of each chlorophyll derivatives in the sample were acquired from the peaks of positive ion atomosphere pressure chemical ionization (APCI) mas spectrometry.

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Study of the Resonance Structures of the Preionizing Spectrum of Molecular Hydrogen by Phase-Shifted Multichannel Quantum Defect Theory II

  • Lee, Chun-Woo
    • Bulletin of the Korean Chemical Society
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    • v.33 no.8
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    • pp.2657-2668
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    • 2012
  • We obtain the general formulation which can handle the rotational preionization spectrum of $H_2$ in the region above its ${H_2}^+$ ionization threshold, ($^2{\sum}_g^+$, ${\nu}^+=0$, $N^+=0$) converging toward its rotationally excited (${\nu}^+=0$, $N^+=2$) limit and perturbed by the vibrationally excited levels $7p{\pi}$ ${\nu}=1$ and $5p{\pi}$ ${\nu}^=2$. The formulation is based on phase-shifted multichannel quantum-defect theory. With this formulation, resonance structures are analyzed in detail.

Hydrogen Generation by Electrical Discharge across Water-Vapor Interface (물-수증기 계면을 통한 전기방전에 의한 수소 제조)

  • Kang, Gou-Jin;Lee, Soo-Chang;Choi, Yong-Man;Lee, Woong-Moo
    • Journal of Hydrogen and New Energy
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    • v.8 no.4
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    • pp.155-160
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    • 1997
  • Generation of hydrogen and oxygen gas from water is mostly accomplished by electrolysis. In this report, a scheme is presented regarding the gas generation based on plasmolysis. Unlike electrolysis water dissociation by electrical discharge (plasmolysis) requires a high voltage to cause either electron emission or electron capture, and subsequent ionization of involved molecular species. When electrical discharge is initiated between electrodes separated by water-vapor interface, a very large electric field(~100kV/cm) is developed at the tip of the electrode placed in the vapor phase. It is found that the efficiency of plasmolysis depends on the polarity of the electrode placed in the vapor phase. Also presented is the scheme of hydrogen and oxygen generation by such electrical discharge.

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An Antimicrobial Activity of a Peptidic Molecule from the Centipede, Scolopendra subspinipes mutilans L. Koch

  • Eun Jae Soon;Leem Jae-Yoon
    • Biomolecules & Therapeutics
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    • v.13 no.4
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    • pp.240-245
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    • 2005
  • An antimicrobial molecule was purified from centipede, Scolopendra subspinipes mutilans L. Koch, by reverse phase-HPLC. Its molecular weight was determined to be 1208.5493 by using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Total amino acid composition analysis revealed that it consists of E, G, P, V, L, F, and W. It exhibited a broad antimicrobial spectrum against not only Gram-negative, but also Gram-positive bacteria. Furthermore, it was found to have an antimicrobial activity against vancomycin resistant enterococci (VRE). It may be a useful molecule for a new antibiotic development, especially against drug-resistant bacteria. We suggest that it may playa role in the defense system of this animal. This is the first report of a peptidic antimicrobial substance from centipede.

Identification of Proteins in Human Follicular Fluid by Proteomic Profiling

  • Sim, Young-Jin;Lee, Mi-Young
    • Molecular & Cellular Toxicology
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    • v.4 no.3
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    • pp.253-259
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    • 2008
  • Human follicular fluid (HFF) is the in vivo microenvironment for oocyte maturation and includes a variety of proteins that could be involved in oocyte development and fertilization. We therefore used a proteomic approach to identify new HFF proteins. HFF from mature human follicles was obtained from five women following oocyte collection for in vitro fertilization (IVF). Ethanol-precipitated HFF run on two-dimensional gel electrophoresis (2DE) produced approximately 250 Coomassie brilliant blue-stained spots, 64 of which were identified using matrix-assisted laser desorption/ionization-mass spectrometry (MALDIMS). In this study, several proteins including complement factor H, inter-${\alpha}$ (globulin) inhibitor H4, inter-${\alpha}$-trypsin inhibitor heavy chain H4 precursor, human zinc-${\alpha}$-2-glycoprotein chain B, PRO2619, PRO02044, and complex-forming glycoprotein HC were new proteins that have not been previously reported in HFF using proteomic methods. Additionally, we identified alloalbumin venezia for the first time from trichloroacetic acid (TCA)-precipitated HFF. These HFF proteins could serve as new biomarkers for important human reproductive processes.

Electrical Breakdown In flames

  • Uhm, Han S.
    • Journal of Korean Vacuum Science & Technology
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    • v.4 no.1
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    • pp.33-37
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    • 2000
  • Properties of electrical discharge in flames and influence of plasma electrons on gas neutrals are investigated by making use of the ionization cross section of air. Frames have three distinctive features. They are hot, emit light and are weakly ionized. We investigate influence of these three characteristics of flames on the electrical breakdown. It is found that the breakdown electric field in flames is inversely proportional to the flame temperature T$\_$g/, thereby easily generating plasmas in flames. A swarm of low-energy electrons in flames would allow a significant population of electronically excited states of flame molecules to be formed. Therefore, the analysis shows that the electronic excitation of flame molecules may also considerably reduce the breakdown field. Plasma electrons generate atomic oxygen by the electron attachment of oxygen molecules in high-pressure flames. These oxygen atoms are the most reactive radicals in flames for material oxidation.

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Determination of the initial cross-sections for the $C_4F_6$ molecule from the electron drift velocity ($C_4F_6$-Ar혼합기체에서의 Plasma Discharge Simulation을 위한 $C_4F_6$ 초기단면적 결정)

  • Lee, Kyung-Yeob;Jeon, Byung-Hoon
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1544-1545
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    • 2011
  • For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. Processing plasma etching of semiconductor, and research are being used in the etching source $C_4F_6$ gas may be used by itself and mixed with other gases are also used. However, the molecular gas $C_4F_6$ study on the characteristics of the electron transport and the cross-sectional area of the decision is still lacking. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients. And to understand and interpret physical properties of the ionization coefficient ${\alpha}$/N, and the attachment coefficient ${\eta}$/N in $C_4F_6$ gas.

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Improvement of Luminance Properties of Blue OLEO using $SnDP(HPB)_2$ (Sn-complexes를 이용한 OLED의 발광 특성 향상에 관한 연구)

  • Kim, Dong-Eun;Choi, Gyu-Chae;Kwon, Young-Soo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04c
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    • pp.121-122
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    • 2008
  • Blue emitting materials have been explored by various researchers. However, blue-emitting materials with high luminous efficiency, good color purity, and thermal stability are still much desired. In this study, we synthesized a new blue luminescent material, $SnDP(HPB)_2$ which is low molecular compound and thermal stability. The PL spectrum of $SnDP(HPB)_2$ was observed blue at the wavelength of 447nm. The ionization potential(IP) and the electron affinity(EA) of $SnDP(HPB)_2$ was measured to be 6.7 eV and 3.0 eV, respectively. The fundamental structure of the OLED was ITO/NPB/$SnDP(HPB)_2/Alq_3$/LiF/Al. As a Result, we obtained to enhance the performance of blue OLED.

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