• 제목/요약/키워드: NMR measurements

검색결과 157건 처리시간 0.033초

리튬고분자 전지의 정극활물질에 관한 전기적 특성 (The Electrical Properties of Cathode Active Materials in Li Polymer Battery System)

  • 나재진;박수길;임기조;이홍기;이주성
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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    • pp.273-276
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    • 1996
  • Polyphenylenediamine(PPD) film was prepared with dimethylsulfoxide after the synthesis of PPD by chemical polymerization. The molecular structure of conductive polymer synthesized were discussed by using SEM, FT-IR, NMR. The electrical conductivity measurements were carried out at room temperature. The electrical conductivity which was obtained from electrical instrument was 1.98${\times}$10$\^$-2/ S/cm at ambient temperature.

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Nuclear Magnetic Relaxation in Flurinated $YBa_2Cu_3O_{7-x}$

  • Lee, Cheol-Eui;White, D.;Davies, P.K.;Moon, B.M.;Sung, M.Y.;Park, J.H.;Kim, B.H.
    • Journal of Magnetics
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    • 제1권1호
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    • pp.1-3
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    • 1996
  • The $YBa_2Cu_3O_{7-x}$ structure has been fluorinated by a gas phase exchange technique. The ${^19}F$NMR (nuclear magnetic resonance) spin-lattice relaxation rate (1/T1) measurements on a fluorinated sample gave superconducting energy gap of $2\Delta=4.6kT_c$.

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12-Hydroxyamoorastatone, a New Limonoid from Melia azedarach var. Japonica

  • Jong-Woong Ahn;Geon-Seek Yoo;Zaesung No;Seung-Ho Lee
    • Bulletin of the Korean Chemical Society
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    • 제14권5호
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    • pp.554-556
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    • 1993
  • A chemical investigation of the stem bark of Melia azedarach var. Japonica (Meliaceae) has led to a new limonoid, 12-hydroxyamoorastatone (1), whose structure has been elucidated by spectroscopic measurements including 2D-NMR. The 2D-NOESY experiment on its di-p-bromobenzoate derivative (1a) has established the relative configuration of 1.

혼성복합재료의 계면 특성 분석 (Characterization of Interface in Hybrid Composites)

  • 하창식;안기열;조원재
    • 접착 및 계면
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    • 제1권1호
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    • pp.47-55
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    • 2000
  • In this article, the characterization of the interface of hybrid composites was discussed. Interfacial interaction in organic/inorganic hybrid composites, especially silica-containing hybrids can be characterized by fluorescence spectroscopy, small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and $^{29}Si$ NMR spectroscopy measurements.

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Preparation of polymeric nanoparticles from hydrophobically modified pullulan for hydrophobic drug carrier

  • Kim, In-Sook;Kim, Sung-Ho
    • 대한약학회:학술대회논문집
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    • 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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    • pp.409.1-409.1
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    • 2002
  • For the development of a biocompatible nano-scale drug carrier. hydrophilic polysaccharide pullulan was hydrophobized by the conjugation with fatty acid. The synthesized polymers were characterized by the measurements of fourier transform infrared (FT -IR) spectroscopy and 1H -nuclear magnetic resonance (NMR) spectroscopy. In aqueous solution. hydrophobically modified puliulan was self-assembled and structured into the core-shell type nanoparticles. (omitted)

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Comparison of Spectral Data of Metabolites Collected from Bruker and Varian 600 MHz Spectrometers

  • Kang, Woo-Young;Chae, Young-Kee
    • 한국자기공명학회논문지
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    • 제13권1호
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    • pp.7-14
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    • 2009
  • The spectral data were collected from the two 600 MHz spectrometers from the two major manufacturers, Broker and Varian. The samples were prepared to create standard curves for quantitative measurements of metabolite concentrations. Instead of employing one-dimensional $^1H$ experiments, the two-dimensional $^1H-^{13}C$ HSQC experiments were performed for better separation of resonances. For some resonances, the high salt condition hindered the linear correlation between the intensity and actual metabolite concentration. Excluding overlapped ones, most resonances showed good linearity. Although the Varian spectrometer showed better linearity, both spectrometers were able to generate acceptable standard curves. From this data, we could identify resonances that could be used to better quantify the concentrations of the particular metabolites. With these standard curves, the quantitative measurements of the metabolites from the real samples will be facilitated.

Spontaneous Copolymerization of 1,3-Dehydroadamantanes

  • Ishizone, Takashi;Matsuoka, Shin-ichi;Uehara, Yousuke;Ogiwara, Naoto
    • 한국고분자학회:학술대회논문집
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    • 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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    • pp.328-328
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    • 2006
  • On mixing of 1,3-dehydroadamantane, 1, with electron-deficient vinyl monomers such as acrylonitrile and methyl acrylate in THF at r.t. in the absence of any initiator, the copolymerization spontaneously proceeded to give alternating copolymers in 28-88 % yield. By contrast, no reaction of 1 occurred, when isobutyl vinyl ether or styrene was mixed under the similar conditions. These contrastive results indicate the high electron density of a central s-bond in a strained [3.3.1]propellane derivative, 1. Alternating sequences of the resulting copolymers were characterized by NMR and MALDI-TOF-MS measurements. DSC and TGA measurements revealed the high thermal stability of the alternating copolymers containing bulky and stiff adamantane skeletons.

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Synthesis and Physicochemical Properties of Schiff Base Macrocyclic Ligands and Their Transition Metal Chelates

  • Rafat, Fouzia;Siddiqi, K.S.
    • 대한화학회지
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    • 제55권6호
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    • pp.912-918
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    • 2011
  • Tetraaza Schiff base macrocyclic ligands, $L^1$,$L^2$ and their transition metal chelates have been synthesized and characterized by elemental analyses, IR, electronic, EPR and $^1H$ NMR spectra, TGA and magnetic measurements. The molar conductance of one milli-molar solution of the complexes measured in DMF indicates that the divalent metal complexes are nonelectrolyte while those of trivalent metal ion, are 1:1 electrolytic in the same solvent. The reduction of Racah parameter from the free ion value confirms the presence of considerable covalence of metal ligand sigma bond in the Co(II) and Mn(II) complexes. The EPR spectra of Cu(II) complexes at room temperature shows axial symmetry indicating a $d_x{^2}_{-y}{^2}$ ground state with significant covalent character. The thermal analysis suggests that the complexes do not contain water molecules because only the metal is left as residue.

$^{13}C$ NMR Studies of Metabolic Pathways Regulated by HSP104 in Saccharomyces cerevisiae

  • 이경희;강수임;Susan Lindquist
    • Bulletin of the Korean Chemical Society
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    • 제19권3호
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    • pp.295-299
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    • 1998
  • HSP104 protein in Saccharomyces cerevisiae is known to provide thermotolerance when induced by various kinds of stresses, such as a mild heat shock, ethanol, and hypoxia. It helps cells survive at an otherwise lethal temperature. Mechanisms by which HSP104 protein works are yet to be elucidated. In order to understand a molecular basis of thermotolerance due to HSP104 protein induced by a mild heat shock, studies on respiratory pathways were carried out in the wild type as well as in the hsp104 deleted mutant. Especially the degree of 13C-acetate incorporation into glutamate-C4 was examined for both strains using 13C-13C homonuclear spin coupling measurements, since glutamate is in a rapid equilibrium with α-ketoglutarate in the TCA cycle. In addition, the temperature effects on the rate of 13C incorporation are compared with or without HSP104 protein expressed. Finally, the inhibitory effect of HSP104 on the respiration pathway was confirmed by the measurements of oxygen consumption rates for both strains.

Micelle Studies of Dodecyltrimethylammonium Bromide in Water as Probed by Benzene: Effect on Shapes and Sizes of Micelles

  • Yoon Seob Lee;Kyu Whan Woo
    • Bulletin of the Korean Chemical Society
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    • 제14권5호
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    • pp.599-602
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    • 1993
  • Micellization process of dodecyltrimethylammonium bromide (DTAB) was studied by using the aromatic probe (benzene) which dissolved in aqueous DTAB solutions. Proton NMR chemical shift measurements of DTAB and DTAB-benzene system showed that benzene molecules solubilized near the micelle-water interface and that the solubilization sites within the micelles are different as the DTAB concentration is passing through 32.0 mM (hereafter we refer this concentration as the second CMC). The change of solubilization sites is also confirmed by abrupt changes of the chemical shifts and relaxation rates of benzene protons in DATB-benzene system at this concentration. It was revealed from the electrical conductivity and viscosity measurements that the solubilization of benzene caused the DTAB micelles to swell out and that the micelles prepared after the second CMC had a greater swelling effect than those prepared before the second CMC. The transition point which reflects the saturation of benzene molecules on the solubilization sites of micelles was observed at one benzene/micellized DTAB mole ratio from the electrical conductivity measurements. Along the different concentration of DTAB solution, this transition point is appeared clearly after the second CMC. From these results it is suggested that the shapes and/or sizes of DTAB micelles of the spherical micelle region prepared after the second CMC are different from those prepared before the second CMC.